Cache Iris Shaders (#2206)

Co-authored-by: Ranzu <[email protected]>
Co-authored-by: Alexdoru <[email protected]>
Co-authored-by: Jason Mitchell <[email protected]>

.gitignore

@@ -47,3 +47,4 @@ dist/tracy-natives/
 *.jfr
 
 tracy-client/angelica/
+shaderc_failures/

build.gradle.kts

@@ -178,6 +178,7 @@ val glCoreTest by tasks.registering(Test::class) {
 tasks.test { finalizedBy(glCoreTest) }
 
 apply(from = "gradle/angelica-shadow-common.gradle.kts")
+apply(from = "experimental-surround/surround.root.gradle.kts")
 
 tasks.withType<TaskPublishCurseForge>().configureEach {
     uploadArtifacts.forEach { it.addGameVersion("Client") }

dependencies.gradle.kts

@@ -202,6 +202,7 @@ afterEvaluate {
         testImplementation(libs.junit.platform.launcher)
 
         testImplementation(libs.archunit.junit5)
+        testImplementation(libs.retrofuturabootstrap) { isTransitive = false }
 
         glsmTestFixtures(testFixtures(project(":glsm")) as ModuleDependency) { isTransitive = false }
         testCompileOnly(testFixtures(project(":glsm")))

experimental-surround/ap/build.gradle.kts

@@ -0,0 +1,58 @@
+plugins {
+    `java-library`
+}
+
+apply(from = rootProject.file("experimental-surround/surround.project.gradle.kts"))
+
+val mixinProviderSpec = rootProject.extra["mixinProviderSpec"] as String
+
+val refmapProbe = sourceSets.create("refmapProbe")
+
+dependencies {
+    compileOnly(mixinProviderSpec)
+    testImplementation(mixinProviderSpec)
+    testImplementation(platform(libs.junit.bom))
+    testImplementation(libs.junit.jupiter)
+    testImplementation(project(":experimental-surround-runtime"))
+    testRuntimeOnly(libs.junit.platform.launcher)
+    "refmapProbeCompileOnly"(mixinProviderSpec)
+    "refmapProbeCompileOnly"(project(":experimental-surround-runtime"))
+    "refmapProbeAnnotationProcessor"(mixinProviderSpec)
+    "refmapProbeAnnotationProcessor"(sourceSets.main.get().output)
+}
+
+val probeRefmaps = layout.buildDirectory.dir("refmap-probe")
+val probeSrg = file("src/refmapProbe/mappings.srg")
+val surroundAp = "com.gtnewhorizons.angelica.experimental.surround.ap.SurroundProcessor"
+val mixinAps = "org.spongepowered.tools.obfuscation.MixinObfuscationProcessorInjection,org.spongepowered.tools.obfuscation.MixinObfuscationProcessorTargets"
+
+fun JavaCompile.probe(name: String, processors: String?) {
+    val refmap = probeRefmaps.map { it.file("refmap-probe/$name.json") }
+    val srg = probeSrg
+    javaCompiler = javaToolchains.compilerFor { languageVersion = JavaLanguageVersion.of(25) }
+    outputs.file(refmap)
+    inputs.file(srg)
+    options.compilerArgumentProviders.add(CommandLineArgumentProvider {
+        listOf("-proc:only", "-AoutRefMapFile=" + refmap.get().asFile.absolutePath,
+            "-AreobfSrgFile=" + srg.absolutePath, "-AdefaultObfuscationEnv=searge") +
+            (if (processors == null) emptyList() else listOf("-processor", processors))
+    })
+}
+
+fun JavaCompile.probeOrdered(name: String, classesDir: String, processors: String) {
+    source = refmapProbe.java
+    classpath = refmapProbe.compileClasspath
+    options.annotationProcessorPath = refmapProbe.annotationProcessorPath
+    destinationDirectory = layout.buildDirectory.dir("classes/$classesDir")
+    probe(name, processors)
+}
+
+tasks.named<JavaCompile>(refmapProbe.compileJavaTaskName) { probe("discovered", null) }
+val probeSurroundFirst by tasks.registering(JavaCompile::class) { probeOrdered("surround-first", "refmapProbeFirst", "$surroundAp,$mixinAps") }
+val probeSurroundLast by tasks.registering(JavaCompile::class) { probeOrdered("surround-last", "refmapProbeLast", "$mixinAps,$surroundAp") }
+
+sourceSets.test { resources.srcDir(files(probeRefmaps).builtBy(refmapProbe.compileJavaTaskName, probeSurroundFirst, probeSurroundLast)) }
+
+tasks.named<Test>("test") {
+    useJUnitPlatform()
+}

experimental-surround/ap/src/main/java/com/gtnewhorizons/angelica/experimental/surround/ap/SurroundProcessor.java

@@ -0,0 +1,77 @@
+package com.gtnewhorizons.angelica.experimental.surround.ap;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.tools.obfuscation.mirror.AnnotationHandle;
+
+import javax.annotation.processing.AbstractProcessor;
+import javax.annotation.processing.ProcessingEnvironment;
+import javax.annotation.processing.RoundEnvironment;
+import javax.annotation.processing.SupportedAnnotationTypes;
+import javax.lang.model.SourceVersion;
+import javax.lang.model.element.AnnotationMirror;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.ExecutableElement;
+import javax.lang.model.element.TypeElement;
+import javax.tools.Diagnostic;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+@SupportedAnnotationTypes("com.gtnewhorizons.angelica.experimental.surround.Surround")
+public class SurroundProcessor extends AbstractProcessor {
+
+    record Registration(TypeElement mixin, ExecutableElement method, AnnotationMirror surround) {
+    }
+
+    private final List<Registration> registrations = new ArrayList<>();
+
+    @Override
+    public SourceVersion getSupportedSourceVersion() {
+        return SourceVersion.latestSupported();
+    }
+
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+        if (roundEnv.processingOver()) {
+            if (!this.registrations.isEmpty()) {
+                register();
+            }
+            return false;
+        }
+        for (TypeElement annotation : annotations) {
+            for (Element annotated : roundEnv.getElementsAnnotatedWith(annotation)) {
+                if (annotated.getEnclosingElement() instanceof TypeElement mixin && AnnotationHandle.of(mixin, Mixin.class).exists()) {
+                    for (AnnotationMirror mirror : annotated.getAnnotationMirrors()) {
+                        if (mirror.getAnnotationType().asElement().equals(annotation)) {
+                            this.registrations.add(new Registration(mixin, (ExecutableElement) annotated, mirror));
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
+    private void register() {
+        final ProcessingEnvironment env = this.processingEnv;
+        try {
+            // pinned by UniMixins 0.3.1; recheck on bump
+            final Class<?> annotatedMixins = Class.forName("org.spongepowered.tools.obfuscation.AnnotatedMixins", false, AnnotationHandle.class.getClassLoader());
+            final Method forEnvironment = annotatedMixins.getDeclaredMethod("getMixinsForEnvironment", ProcessingEnvironment.class);
+            final Method registerInjector = annotatedMixins.getDeclaredMethod("registerInjector", TypeElement.class, ExecutableElement.class, AnnotationHandle.class);
+            final Method writeReferences = annotatedMixins.getDeclaredMethod("writeReferences");
+            forEnvironment.setAccessible(true);
+            registerInjector.setAccessible(true);
+            writeReferences.setAccessible(true);
+            final Object mixins = forEnvironment.invoke(null, env);
+            for (Registration registration : this.registrations) {
+                registerInjector.invoke(mixins, registration.mixin(), registration.method(), AnnotationHandle.of(registration.surround()));
+            }
+            writeReferences.invoke(mixins);
+        } catch (ReflectiveOperationException | LinkageError | RuntimeException e) {
+            env.getMessager().printMessage(Diagnostic.Kind.ERROR, "@Surround: refmap entries were not written: " + e + (e.getCause() == null ? "" : " caused by " + e.getCause()));
+        }
+    }
+}

experimental-surround/ap/src/main/resources/META-INF/services/javax.annotation.processing.Processor

@@ -0,0 +1 @@
+com.gtnewhorizons.angelica.experimental.surround.ap.SurroundProcessor

experimental-surround/ap/src/refmapProbe/java/probe/MixinRefmapTarget.java

@@ -0,0 +1,20 @@
+package probe;
+
+import com.gtnewhorizons.angelica.experimental.surround.Surround;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+
+@Mixin(RefmapTarget.class)
+class MixinRefmapTarget {
+    @Surround(method = "run()V")
+    private void wholeMethod() {}
+
+    @Surround.Finally
+    private void always() {}
+
+    @Surround(method = "run(Ljava/lang/String;)V", id = "call", at = @At(value = "INVOKE", target = "Lprobe/RefmapTarget;helper()V"))
+    private void callForm() {}
+
+    @Surround.Finally("call")
+    private void alwaysCall() {}
+}

experimental-surround/ap/src/refmapProbe/java/probe/RefmapTarget.java

@@ -0,0 +1,7 @@
+package probe;
+
+public class RefmapTarget {
+    void run() {}
+    void run(String s) { helper(); }
+    void helper() {}
+}

experimental-surround/ap/src/refmapProbe/mappings.srg

@@ -0,0 +1,3 @@
+MD: probe/RefmapTarget/run ()V probe/RefmapTarget/func_1_a ()V
+MD: probe/RefmapTarget/run (Ljava/lang/String;)V probe/RefmapTarget/func_2_b (Ljava/lang/String;)V
+MD: probe/RefmapTarget/helper ()V probe/RefmapTarget/func_3_c ()V

experimental-surround/ap/src/test/java/com/gtnewhorizons/angelica/experimental/surround/ap/RefmapRegistrationTest.java

@@ -0,0 +1,37 @@
+package com.gtnewhorizons.angelica.experimental.surround.ap;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class RefmapRegistrationTest {
+
+    private static final Pattern ENTRY = Pattern.compile("\"([^\"]+)\": \"([^\"]+)\"");
+
+    @ParameterizedTest
+    @ValueSource(strings = {"discovered", "surround-first", "surround-last"})
+    void surroundTargetsAreRemappedInTheRefmap(String variant) throws IOException {
+        final Map<String, String> expected = new HashMap<>();
+        expected.put("run()V", "Lprobe/RefmapTarget;func_1_a()V");
+        expected.put("run(Ljava/lang/String;)V", "Lprobe/RefmapTarget;func_2_b(Ljava/lang/String;)V");
+        expected.put("Lprobe/RefmapTarget;helper()V", "Lprobe/RefmapTarget;func_3_c()V");
+        assertEquals(expected, mappings(variant, "probe/MixinRefmapTarget"));
+    }
+
+    private static Map<String, String> mappings(String variant, String mixin) throws IOException {
+        final String json = new String(RefmapRegistrationTest.class.getResourceAsStream("/refmap-probe/" + variant + ".json").readAllBytes(), UTF_8);
+        final int start = json.indexOf('{', json.indexOf("\"" + mixin + "\"", json.indexOf("\"mappings\"")));
+        final Matcher m = ENTRY.matcher(json.substring(start, json.indexOf('}', start)));
+        final Map<String, String> entries = new HashMap<>();
+        while (m.find()) entries.put(m.group(1), m.group(2));
+        return entries;
+    }
+}

experimental-surround/runtime/build.gradle.kts

@@ -0,0 +1,136 @@
+import xyz.wagyourtail.jvmdg.gradle.task.files.DowngradeFiles
+
+plugins {
+    `java-library`
+}
+
+apply(plugin = "xyz.wagyourtail.jvmdowngrader")
+
+apply(from = rootProject.file("experimental-surround/surround.project.gradle.kts"))
+
+// Required by RFG consumers (runClient17 java17Dependencies) to pick a variant.
+val rfgObfAttr = Attribute.of("com.gtnewhorizons.retrofuturagradle.obfuscation", String::class.java)
+val rfgTransformedAttr = Attribute.of("rfgDeobfuscatorTransformed", Boolean::class.javaObjectType)
+
+configurations {
+    listOf("apiElements", "runtimeElements").forEach { name ->
+        named(name) {
+            attributes {
+                attribute(rfgObfAttr, "mcp")
+                attribute(rfgTransformedAttr, true)
+            }
+        }
+    }
+}
+
+val mixinProviderSpec = rootProject.extra["mixinProviderSpec"] as String
+
+dependencies {
+    compileOnly(mixinProviderSpec)
+
+    testImplementation(platform(libs.junit.bom))
+    testImplementation(libs.junit.jupiter)
+    testImplementation(mixinProviderSpec)
+    testImplementation(libs.launchwrapper)
+    testImplementation(libs.commons.io)
+    testImplementation(libs.guava)
+    testImplementation(libs.log4j.core)
+    testRuntimeOnly(libs.junit.platform.launcher)
+    testRuntimeOnly(libs.jvmdowngrader.java.api) { artifact { classifier = "downgraded-8" } }
+}
+
+repositories {
+    maven {
+        name = "WagYourTail"
+        url = uri("https://maven.wagyourtail.xyz/releases")
+        content { includeGroup("xyz.wagyourtail.jvmdowngrader") }
+    }
+}
+
+tasks.withType<DowngradeFiles>().configureEach {
+    downgradeTo.set(JavaVersion.VERSION_1_8)
+    multiReleaseOriginal.set(false)
+    multiReleaseVersions.set(emptySet())
+    logLevel.set("FATAL")
+}
+
+fun SourceSet.registerDowngrade(taskName: String) = tasks.register<DowngradeFiles>(taskName) {
+    inputCollection = output.classesDirs
+    classpath = compileClasspath
+    output.classesDirs.files.forEach { outputs.dir(temporaryDir.resolve(it.name)) }
+    dependsOn(tasks.named(classesTaskName))
+}
+
+val downgradeMainClasses = sourceSets["main"].registerDowngrade("downgradeMainClasses")
+val downgradeTestClasses = sourceSets["test"].registerDowngrade("downgradeTestClasses")
+
+val goldenDir = layout.projectDirectory.dir("src/test/resources/golden").asFile.absolutePath
+
+// Runs on Java 8 against the JVMDowngrader output, the bytecode production ships.
+fun Test.configureSurroundTest(runDirName: String) {
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(8)
+        if (System.getProperty("os.name").lowercase().contains("mac") && System.getProperty("os.arch") == "aarch64") {
+            vendor = JvmVendorSpec.AZUL
+        }
+    }
+    dependsOn(downgradeMainClasses, downgradeTestClasses)
+    val downgradedTest = files(downgradeTestClasses.map { it.outputCollection })
+    testClassesDirs = downgradedTest
+    classpath = downgradedTest
+        .plus(files(downgradeMainClasses.map { it.outputCollection }))
+        .plus(sourceSets["test"].runtimeClasspath.minus(sourceSets["main"].output.classesDirs).minus(sourceSets["test"].output.classesDirs))
+    val dir = layout.buildDirectory.dir(runDirName).get().asFile
+    workingDir = dir
+    systemProperty("surround.golden.dir", goldenDir)
+    systemProperty("mixin.debug.verify", "true")
+    val javac = javaToolchains.compilerFor { languageVersion = JavaLanguageVersion.of(25) }
+    jvmArgumentProviders.add(CommandLineArgumentProvider { listOf("-Dsurround.javac=" + javac.get().executablePath.asFile.absolutePath) })
+    doFirst { dir.mkdirs() }
+}
+
+fun Test.configureUntaggedSurroundTest(runDirName: String, vararg systemProps: Pair<String, String>) {
+    useJUnitPlatform { excludeTags("mixinextras") }
+    for ((key, value) in systemProps) {
+        systemProperty(key, value)
+    }
+    configureSurroundTest(runDirName)
+}
+
+fun Test.configureTaggedSurroundTest(runDirName: String, tag: String, vararg systemProps: Pair<String, String>) {
+    useJUnitPlatform { includeTags(tag) }
+    for ((key, value) in systemProps) {
+        systemProperty(key, value)
+    }
+    configureSurroundTest(runDirName)
+}
+
+tasks.named<Test>("test") {
+    configureUntaggedSurroundTest("test-run")
+}
+
+val mixinExtrasTest by tasks.registering(Test::class) {
+    configureTaggedSurroundTest(
+        "test-run-mixinextras",
+        "mixinextras",
+        "surround.test.mixinextras" to "true"
+    )
+}
+
+val mixinExtrasAdditionsFirstTest by tasks.registering(Test::class) {
+    configureTaggedSurroundTest(
+        "test-run-mixinextras-additions-first",
+        "mixinextras",
+        "surround.test.mixinextras" to "true",
+        "surround.test.additionsFirst" to "true"
+    )
+}
+
+val obfTest by tasks.registering(Test::class) {
+    configureUntaggedSurroundTest("test-run-obf", "surround.test.obf" to "true")
+    filter { excludeTestsMatching("*.RejectionTest") }
+}
+
+tasks.named("check") {
+    dependsOn(mixinExtrasTest, mixinExtrasAdditionsFirstTest, obfTest)
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/CallSiteSpec.java

@@ -0,0 +1,8 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.Exits;
+import org.spongepowered.asm.lib.Type;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.mixin.injection.struct.InjectionNodes.InjectionNode;
+
+record CallSiteSpec(MethodNode target, InjectionNode node, MethodNode entry, String entryDesc, Type[] operands, Type result, Exits exits, String description, int[] entryLocals, int[][] locals) {}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/Surround.java

@@ -0,0 +1,311 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Slice;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Experimental and internal to Angelica; the API may change without notice.
+ * <p>
+ * Surrounds one method call ({@link #at()} set) or a whole method ({@link #at()} empty) with try/catch/finally.
+ * The call form replaces MixinExtras' {@code @WrapOperation} and the whole-method form replaces {@code @WrapMethod},
+ * without their per-call {@code Operation} and {@code Object[]} allocation. Use it when the original runs at most once
+ * with its original arguments.
+ * <p>
+ * A surround can:
+ * <ul>
+ * <li>run code before the original: the entry handler, the annotated method itself;</li>
+ * <li>hand state from that code to everything after it: {@link Carry @Surround.Carry} locals;</li>
+ * <li>read the call's operands, the target's parameters, and locals at the call: operands,
+ * {@link Local @Surround.Local};</li>
+ * <li>skip the original and supply its result instead: {@link Skip @Surround.Skip} + {@link Skipped @Surround.Skipped};</li>
+ * <li>replace the result after a normal completion: {@link Return @Surround.Return};</li>
+ * <li>react to an exception, rethrowing or (calls only) swallowing it and supplying the result:
+ * {@link Catch @Surround.Catch};</li>
+ * <li>run code on every way out: {@link Finally @Surround.Finally}.</li>
+ * </ul>
+ * It cannot call the original twice or with different arguments.
+ *
+ * <h2>Example</h2>
+ * <pre>
+ * &#64;Surround(method = "doRender(Lnet/minecraft/entity/item/EntityItem;DDDFF)V")
+ * private void enter(EntityItem entity, double x, double y, double z, float yaw, float partialTicks) {
+ *     &#64;Surround.Carry int prevItemId = ItemIdManager.getItemId();
+ *     ItemIdManager.setItemId(entity.getEntityItem());
+ * }
+ *
+ * &#64;Surround.Finally
+ * private void restore(&#64;Surround.Carry int prevItemId) {
+ *     ItemIdManager.setItemIdRaw(prevItemId);
+ * }
+ * </pre>
+ *
+ * <h2>Handlers</h2>
+ * The annotated method is the entry handler. Exit handlers are methods in the same mixin whose {@code value} is this
+ * surround's {@link #id()}:
+ * <pre>
+ * &#64;Surround         void enter(operands, &#64;Local params)                         before the original
+ * &#64;Surround.Skipped T    skipped(operands, &#64;Local params, &#64;Carry params)          instead of the original
+ * &#64;Surround.Return  T    ret(T result, operands, &#64;Local params, &#64;Carry params)    after it completes normally
+ * &#64;Surround.Catch   void caught(E error, operands, &#64;Local params, &#64;Carry params)   when it throws E
+ * &#64;Surround.Finally void always(operands, &#64;Local params, &#64;Carry params)         on every way out
+ * </pre>
+ * {@code T} is the return type of the call or method. When it is {@code void}, {@code ret} takes no result and
+ * {@code Skipped} returns {@code void}.
+ * <ul>
+ * <li>The entry handler returns {@code void}. Exit handlers are static exactly when the entry handler is.</li>
+ * <li>Per surround: at most one {@code Skipped}, one {@code Return} and one {@code Finally}, and one {@code Catch} per
+ * exception type. A method has one role.</li>
+ * <li>{@link #id()} is required when the mixin declares more than one {@code @Surround}.</li>
+ * </ul>
+ *
+ * <h2>Parameters</h2>
+ * Declare them in this order, each group optional:
+ * <ol>
+ * <li>Operands, as a leading prefix. For a call: the receiver (unless static), then the arguments. A reference
+ * operand may be declared as a supertype. For a whole method: the target's parameters.</li>
+ * <li>{@link Local @Surround.Local} parameters (call form only). Exit handlers see the value as of entry.</li>
+ * <li>{@link Carry @Surround.Carry} parameters (exit handlers only).</li>
+ * </ol>
+ *
+ * <h2>Carrying state</h2>
+ * Exit handlers see entry-handler locals only through {@link Carry @Surround.Carry}; see there for the rules. Two
+ * carries of one kind are told apart by name:
+ * <pre>
+ * &#64;Surround(method = ..., at = &#64;At(value = "INVOKE", target = ...))
+ * private void enter() {
+ *     &#64;Surround.Carry("depth") int depth = GLStateManager.pushState(StateSet.BLEND);
+ *     &#64;Surround.Carry("prev") int prevProgram = GLStateManager.getActiveProgram();
+ *     &#64;Surround.Carry Class&lt;?&gt; prevRenderable = TesrAttribution.currentRenderable;
+ * }
+ *
+ * &#64;Surround.Finally
+ * private void exit(&#64;Surround.Carry("depth") int depth, &#64;Surround.Carry("prev") int prevProgram,
+ *                   &#64;Surround.Carry Class&lt;?&gt; prevRenderable) { ... }
+ * </pre>
+ *
+ * <h2>Entry-handler body</h2>
+ * <ul>
+ * <li>Every path must fall through to the end: no early {@code return}. Branch with {@code if} instead.</li>
+ * <li>Do not assign its parameters. To change arguments, use {@code @ModifyVariable} or {@code @WrapMethod}.</li>
+ * <li>In the call form it is inlined at every matched call, as are the exit-handler calls. Keep it short: move bulky
+ * logic into a helper and carry the helper's result. Huge targets stop being JIT-compiled past 8000 bytes.</li>
+ * </ul>
+ *
+ * <h2>Skipping</h2>
+ * A {@link Skip @Surround.Skip} local in the entry handler decides whether the original runs; see there for the rules.
+ *
+ * <h2>Order and exceptions</h2>
+ * <ol>
+ * <li>The entry handler. If it throws, nothing else runs.</li>
+ * <li>The original, or {@link Skipped} when skipped.</li>
+ * <li>{@link Return}, only if the original completed normally (not after {@code Skipped}). Its return value replaces
+ * the result.</li>
+ * <li>{@link Finally}, on every way out: normal, after a catch, or rethrowing.</li>
+ * </ol>
+ * {@link Catch} covers step 2, not {@code Return}, and only the most specific matching one runs. It rethrows when
+ * it returns, unless {@link Catch#handle()} is set (call form only): the exception then ends there, and the
+ * handler's return value becomes the call's result.
+ *
+ * <h2>Whole-method form</h2>
+ * <ul>
+ * <li>The original body becomes a private {@code name$surround} method, so stack traces gain that frame.</li>
+ * <li>A {@code synchronized} target holds its lock across the handlers too.</li>
+ * <li>An entry handler that calls the target goes through the surround again.</li>
+ * <li>{@code @Local}, {@link #slice()} and {@code handle} are call-form only.</li>
+ * </ul>
+ *
+ * <h2>With other injectors</h2>
+ * <ul>
+ * <li>A call surround encloses a {@code @Redirect} or {@code @WrapOperation} on the same call. A whole-method surround
+ * encloses every other injection in the method, including call surrounds.</li>
+ * <li>Several surrounds on one call or method nest, lowest priority innermost. An outer skip skips the inner ones
+ * entirely, and {@code Return} replacements chain from inner to outer.</li>
+ * <li>A matched call that another injector removed is skipped with a warning.</li>
+ * </ul>
+ */
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Surround {
+
+    String[] method() default {};
+
+    /**
+     * Calls to surround, as INVOKE-style {@code @At} without shift or by; each match is surrounded separately. Empty
+     * surrounds the whole method.
+     */
+    At[] at() default {};
+
+    /**
+     * As for {@code @Inject}; calls only.
+     */
+    Slice[] slice() default {};
+
+    /**
+     * Names this surround for its exit handlers. Required when the mixin declares more than one {@code @Surround};
+     * unique per mixin.
+     */
+    String id() default "";
+
+    boolean remap() default true;
+
+    /**
+     * As for {@code @Inject}, as are {@link #expect()} and {@link #allow()}; each surrounded call or whole target counts once.
+     */
+    int require() default -1;
+
+    int expect() default 1;
+
+    int allow() default -1;
+
+    /**
+     * Carries a value from the entry handler to the exit handlers.
+     * <p>
+     * Annotate a local in the entry handler, then declare a parameter with the same annotation in any exit handler that
+     * needs the value:
+     * <pre>
+     * &#64;Surround(method = ...)
+     * private void enter() {
+     *     &#64;Surround.Carry int prevItemId = ItemIdManager.getItemId();
+     *     ItemIdManager.setItemId(...);
+     * }
+     *
+     * &#64;Surround.Finally
+     * private void restore(&#64;Surround.Carry int prevItemId) {
+     *     ItemIdManager.setItemIdRaw(prevItemId);
+     * }
+     * </pre>
+     * Declaring the local:
+     * <ul>
+     * <li>Annotate the declaration itself: {@code @Surround.Carry int x = ...}. Not a parameter of the entry handler
+     * (use operands for those), and not part of the type (e.g. an array component).</li>
+     * <li>Declare it at the top level of the entry handler and initialize it there. It must still be in scope and
+     * definitely assigned when the entry handler ends.</li>
+     * </ul>
+     * Receiving it:
+     * <ul>
+     * <li>Carry parameters come last, after operands and {@code @Local} parameters. An exit handler may take any
+     * subset.</li>
+     * <li>Parameters bind to locals by kind: reference, {@code int}-like ({@code boolean}, {@code byte},
+     * {@code char}, {@code short}, {@code int}), {@code long}, {@code float}, {@code double}. If the entry handler
+     * carries two locals of one kind, name every one of that kind with the same {@link #value()} on the local and on
+     * each parameter that reads it: {@code @Surround.Carry("depth") int depth}. Names are unique within a handler.</li>
+     * <li>A reference is cast to the parameter's type on read. Every exit handler must read a given carry as the same
+     * type.</li>
+     * </ul>
+     * Each carry lives in a local slot of the target method, with no allocation, so nested and recursive invocations
+     * keep separate values. The entry handler returns {@code void}; carry its results instead.
+     */
+    @Target({ElementType.TYPE_USE, ElementType.PARAMETER})
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Carry {
+
+        String value() default "";
+    }
+
+    /**
+     * Decides whether the original runs.
+     * <p>
+     * Annotate one {@code boolean} or {@code int}-like local in the entry handler, declared like a {@link Carry}: at
+     * the top level, initialized at its declaration, in scope at the end:
+     * <pre>
+     * &#64;Surround(method = ..., at = &#64;At(value = "INVOKE", target = ...))
+     * private void enter(RenderBlocks renderer, Block block) {
+     *     &#64;Surround.Skip boolean skip = FallingBlockRendering.isActive();
+     * }
+     *
+     * &#64;Surround.Skipped
+     * private boolean replacement(RenderBlocks renderer, Block block) { ... }
+     * </pre>
+     * <ul>
+     * <li>If the local is nonzero when the entry handler ends, the original does not run and {@link Skipped} runs in
+     * its place; {@link Return} does not run after it, {@link Catch} and {@link Finally} still do.</li>
+     * <li>{@link Skipped} is required unless the result is {@code void}, and rejected without a {@code Skip}
+     * local.</li>
+     * <li>At most one per entry handler.</li>
+     * </ul>
+     */
+    @Target(ElementType.TYPE_USE)
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Skip {
+    }
+
+    /**
+     * Supplies the result in place of a skipped original. Required unless that result is {@code void}.
+     */
+    @Target(ElementType.METHOD)
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Skipped {
+
+        /**
+         * The {@link Surround#id()} of the surround this handler belongs to; empty for the default.
+         */
+        String value() default "";
+    }
+
+    /**
+     * Runs after the original completes normally. Takes the result first (none for {@code void}) and returns its
+     * replacement.
+     */
+    @Target(ElementType.METHOD)
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Return {
+
+        /**
+         * The {@link Surround#id()} of the surround this handler belongs to; empty for the default.
+         */
+        String value() default "";
+    }
+
+    /**
+     * Runs when the original or {@link Skipped} throws the first parameter's type, unless a more specific
+     * {@code Catch} matches. Rethrows when it returns.
+     */
+    @Target(ElementType.METHOD)
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Catch {
+
+        /**
+         * The {@link Surround#id()} of the surround this handler belongs to; empty for the default.
+         */
+        String value() default "";
+
+        /**
+         * Call form only: the exception ends here and the returned value becomes the call's result.
+         */
+        boolean handle() default false;
+    }
+
+    /**
+     * Runs on every way out.
+     */
+    @Target(ElementType.METHOD)
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Finally {
+
+        /**
+         * The {@link Surround#id()} of the surround this handler belongs to; empty for the default.
+         */
+        String value() default "";
+    }
+
+    /**
+     * As MixinExtras' {@code @Local}, read at the call; exit handlers see its value at entry. Calls only.
+     */
+    @Target(ElementType.PARAMETER)
+    @Retention(RetentionPolicy.RUNTIME)
+    @interface Local {
+
+        int ordinal() default -1;
+
+        int index() default -1;
+
+        String[] name() default {};
+
+        boolean argsOnly() default false;
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundApplicatorExtension.java

@@ -0,0 +1,120 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.llamalad7.mixinextras.utils.MixinInternals;
+import org.spongepowered.asm.lib.tree.AnnotationNode;
+import org.spongepowered.asm.lib.tree.ClassNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.mixin.MixinEnvironment;
+import org.spongepowered.asm.mixin.transformer.ext.IExtension;
+import org.spongepowered.asm.mixin.transformer.ext.ITargetClassContext;
+import org.spongepowered.asm.util.Annotations;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.WeakHashMap;
+import java.util.regex.Pattern;
+
+final class SurroundApplicatorExtension implements IExtension {
+
+    private static final String MIXINEXTRAS_PACKAGE = "com.llamalad7.mixinextras.";
+    private static final Pattern HANDLER_NAME = Pattern.compile("surround\\$[a-z]{3,}[0-9a-f]{3,}\\$.*");
+
+    private final Map<ITargetClassContext, Pending> pending = new WeakHashMap<>();
+
+    private record Pending(List<CallSiteSpec> calls, List<CallSiteSpec> wholes, Set<String> declarers) {}
+
+    private static final class Holder {
+
+        static final SurroundApplicatorExtension INSTANCE = create();
+
+        private static SurroundApplicatorExtension create() {
+            final SurroundApplicatorExtension extension = new SurroundApplicatorExtension();
+            // MixinExtras 0.5.0 internal (pinned by UniMixins 0.3.1); recheck on bump
+            MixinInternals.registerExtension(extension, false);
+            return extension;
+        }
+    }
+
+    static SurroundApplicatorExtension instance() {
+        return Holder.INSTANCE;
+    }
+
+    void declare(ITargetClassContext context, String mixin) {
+        this.pending(context).declarers.add(mixin);
+    }
+
+    void offer(ITargetClassContext context, CallSiteSpec spec) {
+        final Pending pending = this.pending(context);
+        (spec.node() == null ? pending.wholes : pending.calls).add(spec);
+    }
+
+    private Pending pending(ITargetClassContext context) {
+        return this.pending.computeIfAbsent(context, key -> new Pending(new ArrayList<>(), new ArrayList<>(), new HashSet<>()));
+    }
+
+    @Override
+    public boolean checkActive(MixinEnvironment environment) {
+        return true;
+    }
+
+    @Override
+    public void preApply(ITargetClassContext context) {
+        // MixinExtras 0.5.0 internal (pinned by UniMixins 0.3.1); recheck on bump
+        final List<IExtension> active = MixinInternals.getExtensions().getActiveExtensions();
+        boolean seen = false;
+        for (int i = 0, n = active.size(); i < n; i++) {
+            final IExtension extension = active.get(i);
+            if (extension == this) {
+                seen = true;
+            } else if (seen && extension.getClass().getName().startsWith(MIXINEXTRAS_PACKAGE)) {
+                MixinInternals.unregisterExtension(this);
+                MixinInternals.registerExtension(this, false);
+                return;
+            }
+        }
+    }
+
+    @Override
+    public void postApply(ITargetClassContext context) {
+        final ClassNode targetClass = context.getClassNode();
+        final Pending pending = this.pending.remove(context);
+        checkHandlersRenamed(targetClass, pending == null ? Set.of() : pending.declarers);
+        if (pending == null) {
+            return;
+        }
+        final List<CallSiteSpec> calls = pending.calls;
+        for (int i = 0, n = calls.size(); i < n; i++) {
+            SurroundCallSite.apply(targetClass, calls.get(i));
+        }
+        final List<CallSiteSpec> wholes = pending.wholes;
+        for (int i = 0, n = wholes.size(); i < n; i++) {
+            SurroundCallSite.apply(targetClass, wholes.get(i));
+        }
+    }
+
+    @Override
+    public void export(MixinEnvironment env, String name, boolean force, ClassNode classNode) {
+    }
+
+    static void checkHandlersRenamed(ClassNode classNode, Set<String> declarers) {
+        for (MethodNode method : classNode.methods) {
+            if (method.visibleAnnotations == null) {
+                continue;
+            }
+            for (AnnotationNode annotation : method.visibleAnnotations) {
+                final String desc = annotation.desc;
+                if (SurroundSpec.CATCH.equals(desc) || SurroundSpec.FINALLY.equals(desc) || SurroundSpec.SKIPPED.equals(desc) || SurroundSpec.RETURN.equals(desc)) {
+                    final String mixin = SurroundSpec.mergedBy(method);
+                    if (mixin != null && !declarers.contains(mixin)) {
+                        throw new IllegalStateException("@Surround " + SurroundBinding.exitRef(method) + " " + SurroundInjector.noSurroundForId(Annotations.<String>getValue(annotation, "value", ""), Set.of()));
+                    }
+                } else if (SurroundSpec.SURROUND.equals(desc) && !HANDLER_NAME.matcher(method.name).matches()) {
+                    throw new IllegalStateException(method.name + method.desc + " in " + classNode.name + " (" + SurroundSpec.describeOwner(method) + ") carries @Surround but was never parsed as an injector: the InjectionInfo registry lacked @Surround when mixins were applied to this target; SurroundBootstrap.init() must run before any class a @Surround targets is transformed");
+                }
+            }
+        }
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundBinding.java

@@ -0,0 +1,543 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.spongepowered.asm.lib.Opcodes;
+import org.spongepowered.asm.lib.Type;
+import org.spongepowered.asm.lib.TypePath;
+import org.spongepowered.asm.lib.tree.AbstractInsnNode;
+import org.spongepowered.asm.lib.tree.AnnotationNode;
+import org.spongepowered.asm.lib.tree.FrameNode;
+import org.spongepowered.asm.lib.tree.IincInsnNode;
+import org.spongepowered.asm.lib.tree.LabelNode;
+import org.spongepowered.asm.lib.tree.LocalVariableAnnotationNode;
+import org.spongepowered.asm.lib.tree.LocalVariableNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.lib.tree.VarInsnNode;
+import org.spongepowered.asm.util.Annotations;
+import org.spongepowered.asm.util.Bytecode;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.StringJoiner;
+
+final class SurroundBinding {
+
+    private static final int TOP = -1;
+    private static final String[] SUGARS = {"Local", "Share", "Cancellable"};
+    static final String SUGAR_HINT = ", which a @Surround handler cannot resolve; use @Surround.Carry, or @Surround.Local on a call";
+
+    enum Role {
+        ENTRY(SurroundSpec.SURROUND), CATCH(SurroundSpec.CATCH), FINALLY(SurroundSpec.FINALLY), SKIPPED(SurroundSpec.SKIPPED), RETURN(SurroundSpec.RETURN);
+
+        static final Role[] EXITS = {CATCH, FINALLY, SKIPPED, RETURN};
+
+        final String annotation;
+
+        Role(String annotation) {
+            this.annotation = annotation;
+        }
+    }
+
+    record Load(int slot, Type type) {}
+
+    static final class Handler {
+
+        final MethodNode method;
+        final Role role;
+        final Type[] params;
+        final boolean isStatic;
+        final boolean handles;
+        final int leading;
+        final int localStart;
+        final int carryStart;
+        private final String[] carryIds;
+        int index;
+        Load[] loads;
+
+        Handler(MethodNode method, Role role, int leading) {
+            this.method = method;
+            this.role = role;
+            this.params = Type.getArgumentTypes(method.desc);
+            this.isStatic = Bytecode.isStatic(method);
+            final AnnotationNode caught = role == Role.CATCH ? Annotations.get(method.visibleAnnotations, SurroundSpec.CATCH) : null;
+            this.handles = caught != null && Annotations.<Boolean>getValue(caught, "handle", Boolean.FALSE).booleanValue();
+            this.leading = leading;
+            final int count = this.params.length;
+            int firstLocal = count;
+            int firstCarry = count;
+            int section = 0;
+            String[] ids = null;
+            for (int i = 0; i < count; i++) {
+                final AnnotationNode carry = carry(method, i);
+                final boolean local = local(method, i) != null;
+                if (carry != null && role == Role.ENTRY) {
+                    throw this.reject("has @Surround.Carry on " + paramRef(method, i) + "; only the entry handler's own locals can be carried");
+                }
+                if (local && carry != null) {
+                    throw this.reject(paramRef(method, i) + " cannot be both @Surround.Local and @Surround.Carry");
+                }
+                if ((local || carry != null) && i < leading) {
+                    throw this.reject("cannot mark its " + (role == Role.CATCH ? "caught Throwable" : "result") + " parameter @Surround." + (local ? "Local" : "Carry"));
+                }
+                final int next = carry != null ? 2 : local ? 1 : 0;
+                if (next < section) {
+                    throw this.reject(paramRef(method, i) + " is out of order; declare operands first, then @Surround.Local, then @Surround.Carry parameters");
+                }
+                section = next;
+                if (local && firstLocal == count) {
+                    firstLocal = i;
+                }
+                if (carry != null) {
+                    if (ids == null) {
+                        firstCarry = i;
+                        ids = new String[count - i];
+                    }
+                    ids[i - firstCarry] = Annotations.<String>getValue(carry, "value", "");
+                }
+            }
+            this.localStart = Math.min(firstLocal, firstCarry);
+            this.carryStart = firstCarry;
+            this.carryIds = ids;
+        }
+
+        Type caught() {
+            return this.params[0];
+        }
+
+        String ref() {
+            return this.role == Role.ENTRY ? "entry handler" : exitRef(this.method);
+        }
+
+        SurroundRejection reject(String message) {
+            return new SurroundRejection(this.ref() + " " + message);
+        }
+    }
+
+    static final class Exits {
+
+        final Handler[] handlers;
+        final int catches;
+        final Handler finallyHandler;
+        final Handler skipped;
+        final Handler returnHandler;
+        final boolean handles;
+        final int skipSlot;
+        final Type[] carried;
+        final int argsSize;
+
+        Exits(Handler[] handlers, int skipSlot, Type[] carried) {
+            this.handlers = handlers;
+            int catches = 0;
+            Handler finallyHandler = null;
+            Handler skipped = null;
+            Handler returnHandler = null;
+            boolean handles = false;
+            int argsSize = 0;
+            for (int i = 0; i < handlers.length; i++) {
+                final Handler handler = handlers[i];
+                handler.index = i;
+                handles |= handler.handles;
+                argsSize = Math.max(argsSize, (handler.isStatic ? 0 : 1) + Bytecode.getArgsSize(handler.params));
+                switch (handler.role) {
+                    case CATCH -> catches++;
+                    case FINALLY -> finallyHandler = handler;
+                    case SKIPPED -> skipped = handler;
+                    case RETURN -> returnHandler = handler;
+                }
+            }
+            this.catches = catches;
+            this.finallyHandler = finallyHandler;
+            this.skipped = skipped;
+            this.returnHandler = returnHandler;
+            this.handles = handles;
+            this.skipSlot = skipSlot;
+            this.carried = carried;
+            this.argsSize = argsSize;
+        }
+    }
+
+    private SurroundBinding() {
+    }
+
+    static Type[] bind(MethodNode entry, int[] kinds, Handler[] handlers) {
+        checkNoParameterStores(entry);
+        final List<Carried> carried = carriedLocals(entry, kinds);
+        final Type[] slots = new Type[entry.maxLocals];
+        for (Handler exit : handlers) {
+            final Load[] loads = new Load[exit.params.length - exit.carryStart];
+            for (int i = exit.carryStart; i < exit.params.length; i++) {
+                loads[i - exit.carryStart] = resolve(carried, slots, exit, i);
+            }
+            exit.loads = loads;
+        }
+        return slots;
+    }
+
+    static int skipSlot(MethodNode entry, int[] kinds) {
+        final List<LocalVariableAnnotationNode> annotations = entry.visibleLocalVariableAnnotations;
+        int slot = -1;
+        for (int a = 0, n = annotations == null ? 0 : annotations.size(); a < n; a++) {
+            final LocalVariableAnnotationNode annotation = annotations.get(a);
+            if (!SurroundSpec.SKIP.equals(annotation.desc)) {
+                continue;
+            }
+            if (slot != -1) {
+                throw new SurroundRejection("declares two @Surround.Skip locals; there can only be one");
+            }
+            slot = annotatedSlot(entry, annotation, 0);
+            checkLocalAnnotation(entry, kinds, "@Surround.Skip", annotation, slot, "");
+            if (kinds[slot] != Type.INT) {
+                throw new SurroundRejection("has a @Surround.Skip local that is " + withArticle(kinds[slot]) + "; it must be boolean or int-like");
+            }
+        }
+        return slot;
+    }
+
+    private static AnnotationNode carry(MethodNode method, int index) {
+        final List<AnnotationNode> invisible = parameter(method.invisibleParameterAnnotations, index);
+        for (int i = 0, n = invisible == null ? 0 : invisible.size(); i < n; i++) {
+            final String name = Type.getType(invisible.get(i).desc).getClassName();
+            for (String sugar : SUGARS) {
+                if (name.endsWith("mixinextras.sugar." + sugar)) {
+                    throw new SurroundRejection(paramRef(method, index) + " of '" + method.name + "' is annotated @" + sugar + SUGAR_HINT);
+                }
+            }
+        }
+        return Annotations.get(parameter(method.visibleParameterAnnotations, index), SurroundSpec.CARRY);
+    }
+
+    static AnnotationNode local(MethodNode method, int index) {
+        return Annotations.get(parameter(method.visibleParameterAnnotations, index), SurroundSpec.LOCAL);
+    }
+
+    private static List<AnnotationNode> parameter(List<AnnotationNode>[] table, int index) {
+        return table == null || index >= table.length ? null : table[index];
+    }
+
+    static String paramRef(MethodNode method, int index) {
+        final String name = paramName(method, index);
+        return name == null || name.isEmpty() ? "parameter " + index : "parameter " + index + " ('" + name + "')";
+    }
+
+    static String paramName(MethodNode method, int index) {
+        if (method.localVariables == null) {
+            return null;
+        }
+        final int slot = (Bytecode.isStatic(method) ? 0 : 1) + Bytecode.getArgsSize(Type.getArgumentTypes(method.desc), 0, index);
+        LocalVariableNode earliest = null;
+        int earliestPos = Integer.MAX_VALUE;
+        for (LocalVariableNode local : method.localVariables) {
+            if (local.index != slot) {
+                continue;
+            }
+            final int pos = method.instructions.indexOf(local.start);
+            if (pos < earliestPos) {
+                earliestPos = pos;
+                earliest = local;
+            }
+        }
+        return earliest == null ? null : earliest.name;
+    }
+
+    static AbstractInsnNode soleReturn(MethodNode entry) {
+        AbstractInsnNode sole = null;
+        AbstractInsnNode last = null;
+        int returns = 0;
+        for (AbstractInsnNode insn = entry.instructions.getFirst(); insn != null; insn = insn.getNext()) {
+            if (insn.getOpcode() < 0) {
+                continue;
+            }
+            last = insn;
+            if (insn.getOpcode() == Opcodes.RETURN) {
+                sole = insn;
+                returns++;
+            }
+        }
+        if (returns != 1 || sole != last) {
+            throw new SurroundRejection("must reach its end to hand over to the body; restructure it so every path falls through to its end, with no early return, throw or endless loop");
+        }
+        return sole;
+    }
+
+    private static Load resolve(List<Carried> carried, Type[] slots, Handler exit, int index) {
+        final Type type = exit.params[index];
+        final String id = exit.carryIds[index - exit.carryStart];
+        final int kind = kindOf(type);
+        final boolean named = !id.isEmpty();
+        boolean idDeclared = false;
+        int matches = 0;
+        Carried match = null;
+        for (int i = 0, n = carried.size(); i < n; i++) {
+            final Carried candidate = carried.get(i);
+            if (named && !id.equals(candidate.id())) {
+                continue;
+            }
+            idDeclared = true;
+            if (candidate.kind() == kind) {
+                matches++;
+                match = candidate;
+            }
+        }
+        final String param = paramRef(exit.method, index);
+        if (named && !idDeclared) {
+            throw exit.reject(param + " asks for the carried local '" + id + "', which the entry handler does not declare" + declaredList(carried));
+        }
+        if (matches == 0) {
+            throw exit.reject(param + " is " + type.getClassName() + " (" + withArticle(kind) + "), which matches no carried local of that kind" + declaredList(carried));
+        }
+        if (matches > 1) {
+            throw exit.reject(param + " is " + type.getClassName() + " (" + withArticle(kind) + "), which matches " + matches + " carried locals of that kind; name them with @Surround.Carry(\"...\") on both sides");
+        }
+        final Type existing = slots[match.slot()];
+        if (existing != null && !existing.equals(type)) {
+            throw exit.reject(param + " reads carried local " + match + " as " + type.getClassName() + ", but another exit handler reads it as " + existing.getClassName());
+        }
+        slots[match.slot()] = type;
+        return new Load(match.slot(), type);
+    }
+
+    private static List<Carried> carriedLocals(MethodNode entry, int[] kinds) {
+        final List<Carried> carried = new ArrayList<>();
+        final List<LocalVariableAnnotationNode> annotations = entry.visibleLocalVariableAnnotations;
+        for (int a = 0, n = annotations == null ? 0 : annotations.size(); a < n; a++) {
+            final LocalVariableAnnotationNode annotation = annotations.get(a);
+            if (!SurroundSpec.CARRY.equals(annotation.desc)) {
+                continue;
+            }
+            final int slot = annotatedSlot(entry, annotation, 0);
+            final String id = Annotations.<String>getValue(annotation, "value", "");
+            checkLocalAnnotation(entry, kinds, "@Surround.Carry", annotation, slot, id);
+            if (!id.isEmpty()) {
+                for (int i = 0, count = carried.size(); i < count; i++) {
+                    if (id.equals(carried.get(i).id())) {
+                        throw new SurroundRejection("declares two @Surround.Carry locals named '" + id + "'");
+                    }
+                }
+            }
+            carried.add(new Carried(slot, kinds[slot], id));
+        }
+        return carried;
+    }
+
+    // FML's deobf remapper (ASM LocalVariablesSorter) corrupts annotation indices of long/double locals; the LVT stays right.
+    private static int annotatedSlot(MethodNode entry, LocalVariableAnnotationNode annotation, int range) {
+        final int raw = annotation.index.get(range).intValue();
+        final LabelNode start = annotation.start.get(range);
+        final LabelNode end = annotation.end.get(range);
+        boolean any = false;
+        boolean rawWide = false;
+        boolean rawFound = false;
+        int wide = -1;
+        int wideCount = 0;
+        for (int i = 0, n = entry.localVariables == null ? 0 : entry.localVariables.size(); i < n; i++) {
+            final LocalVariableNode local = entry.localVariables.get(i);
+            if (local.start != start || local.end != end) {
+                continue;
+            }
+            any = true;
+            final boolean isWide = Type.getType(local.desc).getSize() == 2;
+            if (isWide) {
+                wide = local.index;
+                wideCount++;
+            }
+            if (local.index == raw) {
+                rawFound = true;
+                rawWide = isWide;
+            }
+        }
+        final int slot = !any || rawFound && !(rawWide && wideCount > 1) ? raw : wideCount == 1 && !rawFound ? wide : -1;
+        if (slot < 0) {
+            throw new SurroundRejection("has a long or double annotated local that shares its scope with another; initialize it at its declaration");
+        }
+        if (slot >= entry.maxLocals) {
+            throw new SurroundRejection("has an annotated local outside its method's locals (slot " + slot + " of " + entry.maxLocals + "); compile with local variable tables");
+        }
+        return slot;
+    }
+
+    private static void checkLocalAnnotation(MethodNode entry, int[] kinds, String what, LocalVariableAnnotationNode annotation, int slot, String id) {
+        final String local = id.isEmpty() ? "in slot " + slot : "named '" + id + "'";
+        final TypePath path = annotation.typePath;
+        for (int i = 0, length = path == null ? 0 : path.getLength(); i < length; i++) {
+            if (path.getStep(i) != TypePath.ARRAY_ELEMENT) {
+                throw new SurroundRejection("has a " + what + " " + local + " inside the local's type (" + path + "); " + what + " must annotate the local itself, not part of its type");
+            }
+        }
+        for (int i = 1, count = annotation.index.size(); i < count; i++) {
+            if (annotatedSlot(entry, annotation, i) != slot) {
+                throw new SurroundRejection("has a " + what + " local " + local + " recorded in several slots " + annotation.index + "; initialize it at its declaration");
+            }
+        }
+        LabelNode end = annotation.end.get(0);
+        for (int i = 1, n = annotation.end.size(); i < n; i++) {
+            if (entry.instructions.indexOf(annotation.end.get(i)) > entry.instructions.indexOf(end)) {
+                end = annotation.end.get(i);
+            }
+        }
+        for (AbstractInsnNode insn = end.getNext(); insn != null; insn = insn.getNext()) {
+            if (insn.getOpcode() >= 0 && insn.getOpcode() != Opcodes.RETURN) {
+                throw new SurroundRejection("has a " + what + " local " + local + " that goes out of scope before the entry handler ends; declare it in the entry handler's outermost block");
+            }
+        }
+        if (kinds[slot] == TOP) {
+            throw new SurroundRejection("has a " + what + " local " + local + " that is not definitely assigned when the entry handler ends; initialize it at its declaration");
+        }
+    }
+
+    private static void checkNoParameterStores(MethodNode entry) {
+        final int limit = Bytecode.getFirstNonArgLocalIndex(entry);
+        for (AbstractInsnNode insn = entry.instructions.getFirst(); insn != null; insn = insn.getNext()) {
+            final int var;
+            if (insn instanceof VarInsnNode varInsn && storeKind(insn.getOpcode()) != -1) {
+                var = varInsn.var;
+            } else if (insn instanceof IincInsnNode iinc) {
+                var = iinc.var;
+            } else {
+                continue;
+            }
+            if (var < limit) {
+                throw new SurroundRejection("must not assign its parameters; use @ModifyVariable or @WrapMethod to change arguments");
+            }
+        }
+    }
+
+    static int[] kindsAtEnd(MethodNode entry, AbstractInsnNode soleReturn) {
+        final int maxLocals = entry.maxLocals;
+        int[] vars = initialVars(entry);
+        int count = vars.length;
+        int[] state = toSlots(vars, count, maxLocals);
+        for (AbstractInsnNode insn = entry.instructions.getFirst(); insn != soleReturn; insn = insn.getNext()) {
+            if (insn instanceof FrameNode frame) {
+                final int locals = frame.local == null ? 0 : frame.local.size();
+                switch (frame.type) {
+                    case Opcodes.F_NEW, Opcodes.F_FULL, Opcodes.F_APPEND -> {
+                        if (frame.type != Opcodes.F_APPEND) {
+                            count = 0;
+                        }
+                        if (count + locals > vars.length) {
+                            vars = Arrays.copyOf(vars, count + locals);
+                        }
+                        for (int i = 0; i < locals; i++) {
+                            vars[count++] = frameKind(frame.local.get(i));
+                        }
+                    }
+                    case Opcodes.F_CHOP -> count -= locals;
+                    default -> {
+                    }
+                }
+                state = toSlots(vars, count, maxLocals);
+            } else if (insn instanceof VarInsnNode var && storeKind(insn.getOpcode()) != -1) {
+                store(state, var.var, storeKind(insn.getOpcode()));
+            }
+        }
+        return state;
+    }
+
+    private static void store(int[] state, int var, int kind) {
+        if (var > 0 && wide(state[var - 1])) {
+            state[var - 1] = TOP;
+        }
+        state[var] = kind;
+        if (wide(kind) && var + 1 < state.length) {
+            state[var + 1] = TOP;
+        }
+    }
+
+    private static boolean wide(int kind) {
+        return kind == Type.LONG || kind == Type.DOUBLE;
+    }
+
+    private static int[] initialVars(MethodNode entry) {
+        final Type[] args = Type.getArgumentTypes(entry.desc);
+        final int receiver = Bytecode.isStatic(entry) ? 0 : 1;
+        final int[] vars = new int[receiver + args.length];
+        if (receiver != 0) {
+            vars[0] = Type.OBJECT;
+        }
+        for (int i = 0; i < args.length; i++) {
+            vars[receiver + i] = kindOf(args[i]);
+        }
+        return vars;
+    }
+
+    private static int frameKind(Object entry) {
+        if (entry instanceof String || Opcodes.NULL.equals(entry) || Opcodes.UNINITIALIZED_THIS.equals(entry)) {
+            return Type.OBJECT;
+        } else if (Opcodes.INTEGER.equals(entry)) {
+            return Type.INT;
+        } else if (Opcodes.FLOAT.equals(entry)) {
+            return Type.FLOAT;
+        } else if (Opcodes.LONG.equals(entry)) {
+            return Type.LONG;
+        } else if (Opcodes.DOUBLE.equals(entry)) {
+            return Type.DOUBLE;
+        }
+        return TOP;
+    }
+
+    private static int[] toSlots(int[] vars, int count, int maxLocals) {
+        final int[] slots = new int[maxLocals];
+        Arrays.fill(slots, TOP);
+        int slot = 0;
+        for (int i = 0; i < count && slot < maxLocals; i++) {
+            slots[slot] = vars[i];
+            slot += wide(vars[i]) ? 2 : 1;
+        }
+        return slots;
+    }
+
+    private static int storeKind(int opcode) {
+        return switch (opcode) {
+            case Opcodes.ISTORE -> Type.INT;
+            case Opcodes.LSTORE -> Type.LONG;
+            case Opcodes.FSTORE -> Type.FLOAT;
+            case Opcodes.DSTORE -> Type.DOUBLE;
+            case Opcodes.ASTORE -> Type.OBJECT;
+            default -> -1;
+        };
+    }
+
+    static int kindOf(Type type) {
+        return switch (type.getSort()) {
+            case Type.BOOLEAN, Type.CHAR, Type.BYTE, Type.SHORT, Type.INT -> Type.INT;
+            case Type.LONG -> Type.LONG;
+            case Type.FLOAT -> Type.FLOAT;
+            case Type.DOUBLE -> Type.DOUBLE;
+            default -> Type.OBJECT;
+        };
+    }
+
+    private static String kindDescription(int kind) {
+        return switch (kind) {
+            case Type.INT -> "int-like value";
+            case Type.LONG -> "long";
+            case Type.FLOAT -> "float";
+            case Type.DOUBLE -> "double";
+            default -> "reference";
+        };
+    }
+
+    private static String withArticle(int kind) {
+        return (kind == Type.INT ? "an " : "a ") + kindDescription(kind);
+    }
+
+    private static String declaredList(List<Carried> carried) {
+        final StringJoiner all = new StringJoiner(", ", "; the entry handler carries ", "").setEmptyValue("; the entry handler carries nothing");
+        for (Carried local : carried) {
+            all.add(local.toString());
+        }
+        return all.toString();
+    }
+
+    static String exitRef(MethodNode exit) {
+        return "exit handler '" + exit.name + "'";
+    }
+
+    private record Carried(int slot, int kind, String id) {
+
+        @Override
+        public String toString() {
+            return (this.id.isEmpty() ? "an unnamed " + kindDescription(this.kind) : "'" + this.id + "', " + withArticle(this.kind)) + " in slot " + this.slot;
+        }
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundBootstrap.java

@@ -0,0 +1,29 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.spongepowered.asm.launch.GlobalProperties;
+import org.spongepowered.asm.mixin.MixinEnvironment;
+import org.spongepowered.asm.mixin.injection.struct.InjectionInfo;
+import org.spongepowered.asm.mixin.transformer.IMixinTransformer;
+
+public final class SurroundBootstrap {
+
+    private SurroundBootstrap() {
+    }
+
+    private static final class Registration {
+
+        static {
+            InjectionInfo.register(SurroundInjectionInfo.class);
+        }
+
+        static void ensure() {
+        }
+    }
+
+    public static void init() {
+        Registration.ensure();
+        if (GlobalProperties.get(GlobalProperties.Keys.INIT) != null && MixinEnvironment.getDefaultEnvironment().getActiveTransformer() instanceof IMixinTransformer) {
+            SurroundApplicatorExtension.instance();
+        }
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundCallSite.java

@@ -0,0 +1,605 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.Exits;
+import com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.Handler;
+import com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.Load;
+import com.llamalad7.mixinextras.utils.ASMUtils;
+import org.spongepowered.asm.lib.Opcodes;
+import org.spongepowered.asm.lib.Type;
+import org.spongepowered.asm.lib.tree.AbstractInsnNode;
+import org.spongepowered.asm.lib.tree.ClassNode;
+import org.spongepowered.asm.lib.tree.FrameNode;
+import org.spongepowered.asm.lib.tree.IincInsnNode;
+import org.spongepowered.asm.lib.tree.InsnList;
+import org.spongepowered.asm.lib.tree.InsnNode;
+import org.spongepowered.asm.lib.tree.JumpInsnNode;
+import org.spongepowered.asm.lib.tree.LabelNode;
+import org.spongepowered.asm.lib.tree.LocalVariableNode;
+import org.spongepowered.asm.lib.tree.MethodInsnNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.lib.tree.TryCatchBlockNode;
+import org.spongepowered.asm.lib.tree.TypeInsnNode;
+import org.spongepowered.asm.lib.tree.VarInsnNode;
+import org.spongepowered.asm.lib.tree.analysis.Analyzer;
+import org.spongepowered.asm.lib.tree.analysis.AnalyzerException;
+import org.spongepowered.asm.lib.tree.analysis.BasicInterpreter;
+import org.spongepowered.asm.lib.tree.analysis.BasicValue;
+import org.spongepowered.asm.lib.tree.analysis.Frame;
+import org.spongepowered.asm.mixin.injection.struct.InjectionNodes.InjectionNode;
+import org.spongepowered.asm.service.MixinService;
+import org.spongepowered.asm.util.Bytecode;
+import org.spongepowered.asm.util.Bytecode.Visibility;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+final class SurroundCallSite {
+
+    private static final String REGION = "surround:region";
+    private static final Type[] NOTHING = new Type[0];
+
+    record Region(LabelNode start, LabelNode end) {}
+
+    private SurroundCallSite() {
+    }
+
+    static Type[] operands(MethodInsnNode call, String targetClass) {
+        final Type[] args = Type.getArgumentTypes(call.desc);
+        if (call.getOpcode() == Opcodes.INVOKESTATIC) {
+            return args;
+        }
+        final Type[] all = new Type[args.length + 1];
+        all[0] = Type.getObjectType(call.getOpcode() == Opcodes.INVOKESPECIAL ? targetClass : call.owner);
+        System.arraycopy(args, 0, all, 1, args.length);
+        return all;
+    }
+
+    static void apply(ClassNode classNode, CallSiteSpec spec) {
+        final InjectionNode node = spec.node();
+        if (node == null) {
+            final MethodNode target = spec.target();
+            final MethodNode body = relocate(classNode, target);
+            final MethodInsnNode call = (MethodInsnNode) ASMUtils.getInvokeInstruction(classNode, body);
+            target.instructions.add(call);
+            target.instructions.add(new InsnNode(spec.result().getOpcode(Opcodes.IRETURN)));
+            final Type[] args = operands(call, classNode.name);
+            final int[] argSlots = new int[args.length];
+            for (int i = 1; i < args.length; i++) {
+                argSlots[i] = argSlots[i - 1] + args[i - 1].getSize();
+            }
+            emit(classNode, spec, target, call, null, Bytecode.isStatic(target) ? 0 : 1, argSlots);
+            return;
+        }
+        final AbstractInsnNode champion = node.getCurrentTarget();
+        final Region inner = node.<Region>getDecoration(REGION);
+        final MethodNode owner = champion == null ? null : owner(classNode, inner == null ? champion : inner.start());
+        if (owner == null) {
+            MixinService.getService().getLogger("mixin").warn(spec.description() + " skipped: the surrounded call was removed by another injector");
+            return;
+        }
+        if (!spec.entryDesc().equals(spec.entry().desc)) {
+            throw cannotFollow(spec, "the entry handler's descriptor changed from " + spec.entryDesc() + " to " + spec.entry().desc + " after injection", null);
+        }
+        if (!(champion instanceof MethodInsnNode call)) {
+            throw cannotFollow(spec, "the call was replaced by " + Bytecode.describeNode(champion, false) + ", which is not a method call", null);
+        }
+        final int offset = node.isReplaced() && call.getOpcode() != Opcodes.INVOKESTATIC ? 1 : 0;
+        checkOperands(spec, call, operands(call, classNode.name), offset);
+        final Exits exits = spec.exits();
+        final Type result = spec.result();
+        final Type actual = Type.getReturnType(call.desc);
+        if ((exits.handles || exits.skipSlot >= 0 || exits.returnHandler != null) && (actual.getSize() != result.getSize() || actual.getSize() > 0 && SurroundBinding.kindOf(actual) != SurroundBinding.kindOf(result))) {
+            throw cannotFollow(spec, "the call was replaced by " + Bytecode.describeNode(call, false) + ", which returns " + actual.getClassName() + " where the surround supplies or replaces a " + result.getClassName(), null);
+        }
+        emit(classNode, spec, owner, call, inner, offset, null);
+    }
+
+    private static void emit(ClassNode classNode, CallSiteSpec spec, MethodNode owner, MethodInsnNode call, Region inner, int offset, int[] argSlots) {
+        final boolean slots = argSlots != null;
+        final Type[] args = operands(call, classNode.name);
+        final Exits exits = spec.exits();
+        final boolean skips = exits.skipSlot >= 0;
+        final Handler returnHandler = exits.returnHandler;
+        final Type result = spec.result();
+        final Type actual = Type.getReturnType(call.desc);
+
+        final MethodNode entry = spec.entry();
+        final Type[] operands = spec.operands();
+        final int argBase = Bytecode.isStatic(spec.target()) ? 0 : 1;
+        final Type[] entryParams = Type.getArgumentTypes(entry.desc);
+        final int entryOperands = entryParams.length - spec.entryLocals().length;
+        final int firstNonArg = argBase + Bytecode.getArgsSize(entryParams);
+        final MethodNode inlined = inlineable(entry);
+
+        final boolean restoresBelow = exits.handles || !inlined.tryCatchBlocks.isEmpty();
+        final boolean relocated = owner != spec.target();
+        owner.maxLocals = Math.max(Math.max(owner.maxLocals, spec.target().maxLocals), usedLocals(owner));
+        int next = owner.maxLocals;
+        final AbstractInsnNode anchor = inner == null ? call : inner.start();
+        final Frame<BasicValue> frame = !slots && (restoresBelow || relocated && hasLocals(spec)) ? frameAt(owner, anchor, spec) : null;
+        final int shift = relocated ? Bytecode.getFirstNonArgLocalIndex(owner) - Bytecode.getFirstNonArgLocalIndex(spec.target()) : 0;
+
+        final Type[] below = restoresBelow ? below(spec, frame, args.length) : NOTHING;
+        final int spillFrom = slots || restoresBelow || skips ? 0 : offset;
+        final boolean spill = slots || restoresBelow || skips || args.length > offset && (entryOperands > 0 || prefixed(spec));
+        final int[] spillSlots = slots ? argSlots : new int[args.length];
+        if (spill && !slots) {
+            for (int i = spillFrom; i < args.length; i++) {
+                spillSlots[i] = next;
+                next += args[i].getSize();
+            }
+        }
+        final int[] belowSlots = new int[below.length];
+        for (int i = 0; i < below.length; i++) {
+            belowSlots[i] = next;
+            next += below[i].getSize();
+        }
+        final int entryBase = next;
+        final int delta = entryBase - firstNonArg;
+        final int excSlot = entryBase + Math.max(0, inlined.maxLocals - firstNonArg);
+        final int resSlot = excSlot + 1;
+        final boolean storesResult = returnHandler != null && result.getSize() > 0;
+
+        final int[] entryLocals = localSlots(spec, owner, anchor, frame, shift, spec.entryLocals(), entryParams, entryOperands);
+        remapLocals(inlined, argBase, firstNonArg, entryParams, entryOperands, spillSlots, offset, entryLocals, delta);
+        final Handler[] handlers = exits.handlers;
+        final int[][] locals = new int[handlers.length][];
+        for (Handler exit : handlers) {
+            locals[exit.index] = localSlots(spec, owner, anchor, frame, shift, spec.locals()[exit.index], exit.params, exit.localStart);
+        }
+        final Emitter emitter = new Emitter(classNode, exits, operands, Arrays.copyOfRange(spillSlots, offset, offset + operands.length), locals, delta);
+
+        final LabelNode sStart = new LabelNode();
+        final LabelNode tStart = inner == null || skips ? new LabelNode() : inner.start();
+        final LabelNode tEnd = inner == null ? new LabelNode() : inner.end();
+        final LabelNode sEnd = new LabelNode();
+        final LabelNode join = skips ? new LabelNode() : null;
+
+        final InsnList head = new InsnList();
+        head.add(sStart);
+        if (spill && !slots) {
+            for (int i = args.length - 1; i >= spillFrom; i--) {
+                final int j = i - offset;
+                if (j >= 0 && j < operands.length && operands[j].getSort() >= Type.ARRAY && !args[i].equals(operands[j])) {
+                    head.add(new TypeInsnNode(Opcodes.CHECKCAST, operands[j].getInternalName()));
+                }
+                head.add(new VarInsnNode(args[i].getOpcode(Opcodes.ISTORE), spillSlots[i]));
+            }
+            for (int i = below.length - 1; i >= 0; i--) {
+                head.add(new VarInsnNode(below[i].getOpcode(Opcodes.ISTORE), belowSlots[i]));
+            }
+        }
+        head.add(inlined.instructions);
+        if (skips) {
+            final LabelNode callPath = new LabelNode();
+            head.add(new VarInsnNode(Opcodes.ILOAD, exits.skipSlot + delta));
+            head.add(new JumpInsnNode(Opcodes.IFEQ, callPath));
+            head.add(tStart);
+            loadBelow(head, below, belowSlots);
+            emitter.callSkipped(head);
+            head.add(new JumpInsnNode(Opcodes.GOTO, join));
+            head.add(callPath);
+        }
+        if (spill) {
+            loadBelow(head, below, belowSlots);
+            for (int i = spillFrom; i < args.length; i++) {
+                head.add(new VarInsnNode(args[i].getOpcode(Opcodes.ILOAD), spillSlots[i]));
+            }
+        }
+        if (inner == null && !skips) {
+            head.add(tStart);
+        }
+        owner.instructions.insertBefore(anchor, head);
+
+        final InsnList tail = new InsnList();
+        if (inner == null) {
+            tail.add(tEnd);
+        }
+        final LabelNode retStart = returnHandler == null ? null : new LabelNode();
+        final LabelNode retEnd = returnHandler == null ? null : new LabelNode();
+        if (returnHandler != null) {
+            tail.add(retStart);
+            if (result.getSize() > 0) {
+                if (result.getSort() >= Type.ARRAY && !actual.equals(result)) {
+                    tail.add(new TypeInsnNode(Opcodes.CHECKCAST, result.getInternalName()));
+                }
+                tail.add(new VarInsnNode(result.getOpcode(Opcodes.ISTORE), resSlot));
+            }
+            emitter.callReturn(tail, result, resSlot);
+            tail.add(retEnd);
+        }
+        if (skips) {
+            tail.add(join);
+        }
+        emitter.callFinally(tail);
+        tail.add(new JumpInsnNode(Opcodes.GOTO, sEnd));
+        final AbstractInsnNode beforeHandlers = tail.getLast();
+
+        final List<TryCatchBlockNode> blocks = new ArrayList<>(inlined.tryCatchBlocks);
+        emitter.emitHandlers(tail, blocks, tStart, tEnd, retStart, retEnd, excSlot, below, belowSlots, sEnd);
+        final AbstractInsnNode firstHandler = beforeHandlers.getNext();
+        tail.add(sEnd);
+        owner.instructions.insert(inner == null ? call : inner.end(), tail);
+
+        owner.tryCatchBlocks.addAll(insertionIndex(owner, sStart, sEnd), blocks);
+        owner.maxLocals = Math.max(owner.maxLocals, storesResult ? resSlot + result.getSize() : excSlot + 1);
+        owner.maxStack = Math.max(owner.maxStack, spec.target().maxStack) + Math.max(inlined.maxStack, exits.argsSize + 2);
+        if (slots) {
+            final LabelNode end = new LabelNode();
+            owner.instructions.add(end);
+            final List<LocalVariableNode> names = new ArrayList<>();
+            nameParameters(names, classNode, spec, argBase, entryOperands, sStart, end);
+            nameEntryLocals(names, inlined, owner.instructions, exits.carried, firstNonArg, delta, end);
+            if (firstHandler != null) {
+                names.add(new LocalVariableNode("surround$error", SurroundSpec.THROWABLE_DESC, null, (LabelNode) firstHandler, end, excSlot));
+            }
+            if (storesResult) {
+                names.add(new LocalVariableNode("surround$result", result.getDescriptor(), null, retStart, retEnd, resSlot));
+            }
+            owner.localVariables = names;
+        } else {
+            spec.node().decorate(REGION, new Region(sStart, sEnd));
+        }
+    }
+
+    private static void nameParameters(List<LocalVariableNode> names, ClassNode classNode, CallSiteSpec spec, int argBase, int entryOperands, LabelNode start, LabelNode end) {
+        final Type[] params = spec.operands();
+        final MethodNode entry = spec.entry();
+        if (argBase > 0) {
+            names.add(new LocalVariableNode("this", Type.getObjectType(classNode.name).getDescriptor(), null, start, end, 0));
+        }
+        for (int i = 0, slot = argBase; i < params.length; slot += params[i++].getSize()) {
+            final String name = i < entryOperands ? SurroundBinding.paramName(entry, i) : null;
+            names.add(new LocalVariableNode(name != null ? name : "arg" + i, params[i].getDescriptor(), null, start, end, slot));
+        }
+    }
+
+    private static void nameEntryLocals(List<LocalVariableNode> names, MethodNode inlined, InsnList insns, Type[] carried, int firstNonArg, int delta, LabelNode end) {
+        final LocalVariableNode[] furthest = new LocalVariableNode[carried.length];
+        for (LocalVariableNode local : inlined.localVariables) {
+            if (!isCarried(carried, local.index)) {
+                continue;
+            }
+            final LocalVariableNode current = furthest[local.index];
+            if (current == null || insns.indexOf(local.end) > insns.indexOf(current.end)) {
+                furthest[local.index] = local;
+            }
+        }
+        for (LocalVariableNode local : inlined.localVariables) {
+            if (local.index < firstNonArg) {
+                continue;
+            }
+            if (isCarried(carried, local.index) && local == furthest[local.index]) {
+                final Type type = carried[local.index];
+                names.add(new LocalVariableNode(local.name, type.getSort() >= Type.ARRAY ? local.desc : type.getDescriptor(), null, local.start, end, local.index + delta));
+            } else {
+                local.index += delta;
+                names.add(local);
+            }
+        }
+    }
+
+    private static boolean isCarried(Type[] carried, int slot) {
+        return slot < carried.length && carried[slot] != null;
+    }
+
+    private static MethodNode inlineable(MethodNode entry) {
+        final MethodNode copy = new MethodNode(entry.access, entry.name, entry.desc, null, null);
+        entry.accept(copy);
+        for (AbstractInsnNode insn = copy.instructions.getFirst(); insn != null; ) {
+            final AbstractInsnNode next = insn.getNext();
+            if (insn instanceof FrameNode) {
+                copy.instructions.remove(insn);
+            }
+            insn = next;
+        }
+        AbstractInsnNode last = copy.instructions.getLast();
+        while (last.getOpcode() < 0) {
+            last = last.getPrevious();
+        }
+        copy.instructions.remove(last);
+        return copy;
+    }
+
+    private static MethodNode relocate(ClassNode classNode, MethodNode target) {
+        final MethodNode body = new MethodNode(target.access & ~Opcodes.ACC_SYNCHRONIZED, unique(classNode, target.name + "$surround"), target.desc, null, null);
+        Bytecode.setVisibility(body, Visibility.PRIVATE);
+        body.instructions = target.instructions;
+        body.instructions.resetLabels();
+        body.tryCatchBlocks = target.tryCatchBlocks;
+        body.localVariables = target.localVariables;
+        body.visibleLocalVariableAnnotations = target.visibleLocalVariableAnnotations;
+        body.invisibleLocalVariableAnnotations = target.invisibleLocalVariableAnnotations;
+        body.maxStack = target.maxStack;
+        body.maxLocals = target.maxLocals;
+
+        target.instructions = new InsnList();
+        target.tryCatchBlocks = new ArrayList<>();
+        target.visibleLocalVariableAnnotations = null;
+        target.invisibleLocalVariableAnnotations = null;
+        target.maxLocals = target.maxStack = Bytecode.getFirstNonArgLocalIndex(target);
+        classNode.methods.add(body);
+        return body;
+    }
+
+    private static String unique(ClassNode classNode, String base) {
+        String name = base;
+        for (int i = 1; ; name = base + "$" + i++) {
+            final String candidate = name;
+            if (classNode.methods.stream().noneMatch(method -> method.name.equals(candidate))) {
+                return name;
+            }
+        }
+    }
+
+    private static boolean hasLocals(CallSiteSpec spec) {
+        if (spec.entryLocals().length > 0) {
+            return true;
+        }
+        for (int[] locals : spec.locals()) {
+            if (locals.length > 0) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static Frame<BasicValue> frameAt(MethodNode owner, AbstractInsnNode anchor, CallSiteSpec spec) {
+        final int index = owner.instructions.indexOf(anchor);
+        for (owner.maxStack = Math.max(owner.maxStack, spec.target().maxStack) + 16; ; owner.maxStack <<= 1) {
+            try {
+                return new Analyzer<>(new BasicInterpreter()).analyze(owner.name, owner)[index];
+            } catch (AnalyzerException e) {
+                if (!(e.getCause() instanceof IndexOutOfBoundsException) || owner.maxStack > 0xFFFF) {
+                    throw cannotFollow(spec, "cannot analyze " + owner.name + owner.desc, e);
+                }
+            }
+        }
+    }
+
+    private static Type[] below(CallSiteSpec spec, Frame<BasicValue> frame, int args) {
+        final int count = frame == null ? 0 : frame.getStackSize() - args;
+        if (count <= 0) {
+            return NOTHING;
+        }
+        final Type[] below = new Type[count];
+        for (int i = 0; i < count; i++) {
+            final BasicValue value = frame.getStack(i);
+            final Type type = value.getType();
+            if (type == null || type.getSort() == Type.VOID) {
+                throw cannotFollow(spec, "stack value " + i + " below the call is " + value + ", which cannot be restored", null);
+            }
+            below[i] = value.isReference() ? Type.getObjectType(SurroundSpec.OBJECT) : type;
+        }
+        return below;
+    }
+
+    private static int[] localSlots(CallSiteSpec spec, MethodNode owner, AbstractInsnNode anchor, Frame<BasicValue> frame, int shift, int[] resolved, Type[] params, int first) {
+        if (resolved.length == 0 || owner == spec.target()) {
+            return resolved;
+        }
+        final int firstNonArg = Bytecode.getFirstNonArgLocalIndex(spec.target());
+        final int[] slots = new int[resolved.length];
+        for (int i = 0; i < resolved.length; i++) {
+            final int slot = resolved[i] < firstNonArg ? resolved[i] : resolved[i] + shift;
+            checkLocal(spec, owner, anchor, frame, slot, params[first + i], resolved[i]);
+            slots[i] = slot;
+        }
+        return slots;
+    }
+
+    private static void checkLocal(CallSiteSpec spec, MethodNode owner, AbstractInsnNode anchor, Frame<BasicValue> frame, int slot, Type type, int resolved) {
+        String found = null;
+        if (owner.localVariables != null) {
+            final int at = owner.instructions.indexOf(anchor);
+            for (LocalVariableNode local : owner.localVariables) {
+                if (local.index == slot && owner.instructions.indexOf(local.start) <= at && at < owner.instructions.indexOf(local.end) && !type.getDescriptor().equals(local.desc)) {
+                    found = Type.getType(local.desc).getClassName() + " '" + local.name + "'";
+                }
+            }
+        }
+        if (found == null && frame != null) {
+            final BasicValue value = slot < frame.getLocals() ? frame.getLocal(slot) : null;
+            final Type actual = value == null ? null : value.getType();
+            if (actual == null || actual.getSort() == Type.VOID || actual.getSize() != type.getSize() || SurroundBinding.kindOf(actual) != SurroundBinding.kindOf(type)) {
+                found = value == null ? "nothing" : String.valueOf(value);
+            }
+        }
+        if (found != null) {
+            throw cannotFollow(spec, "@Surround.Local " + type.getClassName() + " resolved to local " + resolved + " at injection, but after the body moved to " + owner.name + owner.desc + " local " + slot + " holds " + found, null);
+        }
+    }
+
+    private static MethodNode owner(ClassNode classNode, AbstractInsnNode insn) {
+        AbstractInsnNode first = insn;
+        while (first.getPrevious() != null) {
+            first = first.getPrevious();
+        }
+        final List<MethodNode> methods = classNode.methods;
+        for (int i = 0, n = methods.size(); i < n; i++) {
+            if (methods.get(i).instructions.getFirst() == first) {
+                return methods.get(i);
+            }
+        }
+        return null;
+    }
+
+    private static void checkOperands(CallSiteSpec spec, MethodInsnNode call, Type[] args, int offset) {
+        final Type[] operands = spec.operands();
+        if (args.length - offset < operands.length) {
+            throw cannotFollow(spec, "the call was replaced by " + Bytecode.describeNode(call, false) + ", which takes fewer arguments than the surrounded call", null);
+        }
+        for (int i = 0; i < operands.length; i++) {
+            if (SurroundBinding.kindOf(args[offset + i]) != SurroundBinding.kindOf(operands[i])) {
+                throw cannotFollow(spec, "the call was replaced by " + Bytecode.describeNode(call, false) + ", whose argument " + (offset + i) + " is " + args[offset + i].getClassName() + " where the surrounded call passed " + operands[i].getClassName(), null);
+            }
+        }
+    }
+
+    private static IllegalStateException cannotFollow(CallSiteSpec spec, String detail, Throwable cause) {
+        return new IllegalStateException(spec.description() + " cannot be applied, another transformation left the site in a shape it cannot follow: " + detail, cause);
+    }
+
+    private static boolean prefixed(CallSiteSpec spec) {
+        for (Handler exit : spec.exits().handlers) {
+            if (exit.localStart > exit.leading) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static int usedLocals(MethodNode owner) {
+        int max = Bytecode.getFirstNonArgLocalIndex(owner);
+        for (AbstractInsnNode insn = owner.instructions.getFirst(); insn != null; insn = insn.getNext()) {
+            if (insn instanceof VarInsnNode varInsn) {
+                final int opcode = insn.getOpcode();
+                final boolean wide = opcode == Opcodes.LLOAD || opcode == Opcodes.DLOAD || opcode == Opcodes.LSTORE || opcode == Opcodes.DSTORE;
+                max = Math.max(max, varInsn.var + (wide ? 2 : 1));
+            } else if (insn instanceof IincInsnNode iinc) {
+                max = Math.max(max, iinc.var + 1);
+            }
+        }
+        return max;
+    }
+
+    private static void remapLocals(MethodNode inlined, int argBase, int firstNonArg, Type[] entryParams, int entryOperands, int[] spillSlots, int offset, int[] entryLocals, int delta) {
+        final int[] paramSlots = new int[firstNonArg];
+        for (int i = 0, slot = argBase; i < entryParams.length; i++) {
+            paramSlots[slot] = i < entryOperands ? spillSlots[offset + i] : entryLocals[i - entryOperands];
+            slot += entryParams[i].getSize();
+        }
+        for (AbstractInsnNode insn = inlined.instructions.getFirst(); insn != null; insn = insn.getNext()) {
+            if (insn instanceof VarInsnNode var) {
+                var.var = remap(var.var, argBase, firstNonArg, paramSlots, delta);
+            } else if (insn instanceof IincInsnNode iinc) {
+                iinc.var = remap(iinc.var, argBase, firstNonArg, paramSlots, delta);
+            }
+        }
+    }
+
+    private static int remap(int var, int argBase, int firstNonArg, int[] paramSlots, int delta) {
+        if (var < argBase) {
+            return var;
+        }
+        if (var < firstNonArg) {
+            return paramSlots[var];
+        }
+        return var + delta;
+    }
+
+    private static int insertionIndex(MethodNode owner, LabelNode start, LabelNode end) {
+        final List<TryCatchBlockNode> blocks = owner.tryCatchBlocks;
+        final InsnList insns = owner.instructions;
+        final int from = insns.indexOf(start);
+        final int to = insns.indexOf(end);
+        for (int i = 0, n = blocks.size(); i < n; i++) {
+            final TryCatchBlockNode block = blocks.get(i);
+            final int s = insns.indexOf(block.start);
+            final int e = insns.indexOf(block.end);
+            if (s < to && e > from && (s < from || e > to)) {
+                return i;
+            }
+        }
+        return blocks.size();
+    }
+
+    private static void loadBelow(InsnList insns, Type[] below, int[] belowSlots) {
+        for (int i = 0; i < below.length; i++) {
+            insns.add(new VarInsnNode(below[i].getOpcode(Opcodes.ILOAD), belowSlots[i]));
+        }
+    }
+
+    private record Emitter(ClassNode classNode, Exits exits, Type[] operands, int[] operandSlots, int[][] locals, int delta) {
+
+        private void invoke(InsnList insns, Handler exit, Type leading, int leadingSlot) {
+            final int[] locals = this.locals[exit.index];
+            if (!exit.isStatic) {
+                insns.add(new VarInsnNode(Opcodes.ALOAD, 0));
+            }
+            if (leading != null) {
+                insns.add(new VarInsnNode(leading.getOpcode(Opcodes.ILOAD), leadingSlot));
+            }
+            for (int i = 0, n = exit.localStart - exit.leading; i < n; i++) {
+                insns.add(new VarInsnNode(this.operands[i].getOpcode(Opcodes.ILOAD), this.operandSlots[i]));
+            }
+            for (int i = exit.localStart; i < exit.carryStart; i++) {
+                insns.add(new VarInsnNode(exit.params[i].getOpcode(Opcodes.ILOAD), locals[i - exit.localStart]));
+            }
+            for (Load load : exit.loads) {
+                final Type type = load.type();
+                insns.add(new VarInsnNode(type.getOpcode(Opcodes.ILOAD), load.slot() + this.delta));
+                if (type.getSort() >= Type.ARRAY && !SurroundSpec.OBJECT.equals(type.getInternalName())) {
+                    insns.add(new TypeInsnNode(Opcodes.CHECKCAST, type.getInternalName()));
+                }
+            }
+            // MixinExtras 0.5.0 internal (pinned by UniMixins 0.3.1); recheck on bump
+            insns.add(ASMUtils.getInvokeInstruction(this.classNode, exit.method));
+        }
+
+        void callFinally(InsnList insns) {
+            if (this.exits.finallyHandler != null) {
+                this.invoke(insns, this.exits.finallyHandler, null, 0);
+            }
+        }
+
+        void callSkipped(InsnList insns) {
+            if (this.exits.skipped != null) {
+                this.invoke(insns, this.exits.skipped, null, 0);
+            }
+        }
+
+        void callReturn(InsnList insns, Type result, int resSlot) {
+            this.invoke(insns, this.exits.returnHandler, result.getSize() > 0 ? result : null, resSlot);
+        }
+
+        void emitHandlers(InsnList tail, List<TryCatchBlockNode> blocks, LabelNode start, LabelNode end, LabelNode retStart, LabelNode retEnd, int excSlot, Type[] below, int[] belowSlots, LabelNode handledExit) {
+            final Handler[] handlers = this.exits.handlers;
+            final boolean hasFinally = this.exits.finallyHandler != null;
+            final LabelNode catchAll = hasFinally ? new LabelNode() : null;
+            final List<TryCatchBlockNode> catchAlls = hasFinally ? new ArrayList<>() : null;
+            for (int k = 0; k < this.exits.catches; k++) {
+                final Handler exit = handlers[k];
+                final LabelNode handler = new LabelNode();
+                final LabelNode exitStart = new LabelNode();
+                final LabelNode exitEnd = new LabelNode();
+
+                tail.add(handler);
+                tail.add(new VarInsnNode(Opcodes.ASTORE, excSlot));
+                if (exit.handles) {
+                    loadBelow(tail, below, belowSlots);
+                }
+                tail.add(exitStart);
+                this.invoke(tail, exit, exit.caught(), excSlot);
+                tail.add(exitEnd);
+
+                this.callFinally(tail);
+                if (exit.handles) {
+                    tail.add(new JumpInsnNode(Opcodes.GOTO, handledExit));
+                } else {
+                    tail.add(new VarInsnNode(Opcodes.ALOAD, excSlot));
+                    tail.add(new InsnNode(Opcodes.ATHROW));
+                }
+
+                blocks.add(new TryCatchBlockNode(start, end, handler, exit.caught().getInternalName()));
+                if (hasFinally) {
+                    catchAlls.add(new TryCatchBlockNode(exitStart, exitEnd, catchAll, null));
+                }
+            }
+            if (hasFinally) {
+                tail.add(catchAll);
+                tail.add(new VarInsnNode(Opcodes.ASTORE, excSlot));
+                this.callFinally(tail);
+                tail.add(new VarInsnNode(Opcodes.ALOAD, excSlot));
+                tail.add(new InsnNode(Opcodes.ATHROW));
+
+                if (retStart != null) {
+                    catchAlls.add(new TryCatchBlockNode(retStart, retEnd, catchAll, null));
+                }
+                catchAlls.add(new TryCatchBlockNode(start, end, catchAll, null));
+                blocks.addAll(catchAlls);
+            }
+        }
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundInjectionInfo.java

@@ -0,0 +1,72 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.spongepowered.asm.lib.tree.AnnotationNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.code.Injector;
+import org.spongepowered.asm.mixin.injection.struct.InjectionInfo;
+import org.spongepowered.asm.mixin.injection.throwables.InvalidInjectionException;
+import org.spongepowered.asm.mixin.transformer.MixinTargetContext;
+import org.spongepowered.asm.util.Annotations;
+
+import java.util.List;
+
+@InjectionInfo.AnnotationType(Surround.class)
+@InjectionInfo.HandlerPrefix("surround")
+public final class SurroundInjectionInfo extends InjectionInfo {
+
+    boolean callSite;
+
+    public SurroundInjectionInfo(MixinTargetContext mixin, MethodNode method, AnnotationNode annotation) {
+        super(mixin, method, annotation);
+    }
+
+    @Override
+    protected void readInjectionPoints() {
+        final List<AnnotationNode> ats = Annotations.<AnnotationNode>getValue(this.annotation, this.atKey, false);
+        this.callSite = ats != null && !ats.isEmpty();
+        if (this.callSite) {
+            super.readInjectionPoints();
+            return;
+        }
+        final List<AnnotationNode> slices = Annotations.<AnnotationNode>getValue(this.annotation, "slice", false);
+        if (slices != null && !slices.isEmpty()) {
+            throw this.reject("declares @Surround.slice, which only applies when @Surround.at selects a call");
+        }
+    }
+
+    @Override
+    protected void parseInjectionPoints(List<AnnotationNode> ats) {
+        if (!this.callSite) {
+            this.injectionPoints.add(new SurroundInjectionPoint());
+            return;
+        }
+        for (int i = 0, n = ats.size(); i < n; i++) {
+            final AnnotationNode at = ats.get(i);
+            final String code = Annotations.<String>getValue(at, "value");
+            if (!selectsCall(code)) {
+                throw this.reject("has @At(\"" + code + "\"), which does not select a method call");
+            }
+            if (Annotations.<At.Shift>getValue(at, "shift", At.Shift.class, At.Shift.NONE) != At.Shift.NONE || Annotations.<Integer>getValue(at, "by", Integer.valueOf(0)).intValue() != 0) {
+                throw this.reject("has @At(\"" + code + "\") with a non-default shift or by, which moves the match off the call");
+            }
+        }
+        super.parseInjectionPoints(ats);
+    }
+
+    private static boolean selectsCall(String atCode) {
+        return switch (atCode) {
+            case "HEAD", "RETURN", "TAIL", "CTOR_HEAD", "FIELD", "NEW", "CONSTANT", "JUMP", "INVOKE_ASSIGN", "LOAD", "STORE" -> false;
+            default -> true;
+        };
+    }
+
+    private InvalidInjectionException reject(String message) {
+        return new InvalidInjectionException(this, "@Surround " + this.getMethodName() + " " + message);
+    }
+
+    @Override
+    protected Injector parseInjector(AnnotationNode injectAnnotation) {
+        return new SurroundInjector(this);
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundInjectionPoint.java

@@ -0,0 +1,20 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.spongepowered.asm.lib.tree.AbstractInsnNode;
+import org.spongepowered.asm.lib.tree.InsnList;
+import org.spongepowered.asm.mixin.injection.InjectionPoint;
+
+import java.util.Collection;
+
+final class SurroundInjectionPoint extends InjectionPoint {
+
+    @Override
+    public boolean checkPriority(int targetPriority, int ownerPriority) {
+        return true;
+    }
+
+    @Override
+    public boolean find(String desc, InsnList insns, Collection<AbstractInsnNode> nodes) {
+        return nodes.add(insns.getFirst());
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundInjector.java

@@ -0,0 +1,378 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.Exits;
+import com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.Handler;
+import com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.Role;
+import com.llamalad7.mixinextras.utils.InjectorUtils;
+import org.spongepowered.asm.lib.Opcodes;
+import org.spongepowered.asm.lib.Type;
+import org.spongepowered.asm.lib.tree.AbstractInsnNode;
+import org.spongepowered.asm.lib.tree.AnnotationNode;
+import org.spongepowered.asm.lib.tree.LocalVariableAnnotationNode;
+import org.spongepowered.asm.lib.tree.MethodInsnNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.mixin.injection.InjectionPoint;
+import org.spongepowered.asm.mixin.injection.code.Injector;
+import org.spongepowered.asm.mixin.injection.modify.InvalidImplicitDiscriminatorException;
+import org.spongepowered.asm.mixin.injection.modify.LocalVariableDiscriminator;
+import org.spongepowered.asm.mixin.injection.modify.LocalVariableDiscriminator.Context;
+import org.spongepowered.asm.mixin.injection.struct.InjectionNodes.InjectionNode;
+import org.spongepowered.asm.mixin.injection.struct.Target;
+import org.spongepowered.asm.mixin.injection.throwables.InvalidInjectionException;
+import org.spongepowered.asm.mixin.transformer.ClassInfo;
+import org.spongepowered.asm.mixin.transformer.ClassInfo.Traversal;
+import org.spongepowered.asm.mixin.transformer.MixinTargetContext;
+import org.spongepowered.asm.util.Annotations;
+import org.spongepowered.asm.util.Bytecode;
+import org.spongepowered.asm.util.asm.MethodNodeEx;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Locale;
+import java.util.Set;
+import java.util.StringJoiner;
+
+import static com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.exitRef;
+import static com.gtnewhorizons.angelica.experimental.surround.SurroundBinding.paramRef;
+
+final class SurroundInjector extends Injector {
+
+    private final String id;
+    private final boolean callSite;
+    private final MixinTargetContext mixin;
+    private Handler entry;
+    private Exits exits;
+
+    SurroundInjector(SurroundInjectionInfo info) {
+        super(info, "@Surround");
+        this.id = info.getAnnotation().getValue("id", "");
+        this.callSite = info.callSite;
+        this.mixin = (MixinTargetContext) info.getMixin();
+        SurroundApplicatorExtension.instance().declare(this.mixin.getTarget(), this.mixin.getClassName());
+    }
+
+    @Override
+    protected void inject(Target target, InjectionNode node) {
+        this.checkTargetModifiers(target, true);
+        try {
+            if (this.callSite) {
+                this.surroundCall(target, node);
+            } else {
+                final Type result = Type.getReturnType(target.method.desc);
+                this.prepare(target.arguments, result, target.toString());
+                this.offer(target, null, target.arguments, result, target.toString());
+            }
+        } catch (SurroundRejection e) {
+            throw error(e.getMessage());
+        }
+    }
+
+    private void surroundCall(Target target, InjectionNode node) {
+        final AbstractInsnNode insn = node.getOriginalTarget();
+        if (!(insn instanceof MethodInsnNode call)) {
+            throw error("at must select a method call, not " + Bytecode.describeNode(insn, false) + " in " + target);
+        }
+        final String site = "call " + call.owner + "." + call.name + call.desc + " in " + target;
+        if ("<init>".equals(call.name)) {
+            throw error("at must select a method call, not the constructor " + site);
+        }
+        final Type[] operands = SurroundCallSite.operands(call, this.classNode.name);
+        final Type result = Type.getReturnType(call.desc);
+        this.prepare(operands, result, site);
+        final boolean insideNew = isInsideNew(call);
+        if (insideNew && this.methodNode.tryCatchBlocks != null && !this.methodNode.tryCatchBlocks.isEmpty()) {
+            throw error("must not catch exceptions when it surrounds a call inside a constructor call's arguments (between NEW and <init>); move the try into a method it calls");
+        }
+        if (insideNew && this.exits.handles) {
+            throw error("has a @Surround.Catch" + this.forId() + " that declares handle = true, but the call is inside a constructor call's arguments (between NEW and <init>), where the values below it cannot be restored");
+        }
+        this.offer(target, node, operands, result, site);
+    }
+
+    private void offer(Target target, InjectionNode node, Type[] operands, Type result, String site) {
+        final Handler[] handlers = this.exits.handlers;
+        final int[][] locals = new int[handlers.length][];
+        for (Handler exit : handlers) {
+            locals[exit.index] = this.resolveLocals(target, node, exit);
+        }
+        final int[] entryLocals = this.resolveLocals(target, node, this.entry);
+        this.info.addCallbackInvocation(this.methodNode);
+        final String description = "@Surround " + this.mixin.getClassName() + "::" + this.info.getMethodName() + " surrounding " + site;
+        SurroundApplicatorExtension.instance().offer(this.mixin.getTarget(), new CallSiteSpec(target.method, node, this.methodNode, this.methodNode.desc, operands, result, this.exits, description, entryLocals, locals));
+    }
+
+    private static boolean isInsideNew(MethodInsnNode call) {
+        int constructed = 0;
+        for (AbstractInsnNode insn = call.getPrevious(); insn != null; insn = insn.getPrevious()) {
+            if (insn.getOpcode() == Opcodes.INVOKESPECIAL && "<init>".equals(((MethodInsnNode) insn).name)) {
+                constructed++;
+            } else if (insn.getOpcode() == Opcodes.NEW) {
+                if (constructed == 0) {
+                    return true;
+                }
+                constructed--;
+            }
+        }
+        return false;
+    }
+
+    private int[] resolveLocals(Target target, InjectionNode node, Handler handler) {
+        final int from = handler.localStart;
+        final int[] slots = new int[handler.carryStart - from];
+        for (int i = from; i < handler.carryStart; i++) {
+            final Type type = handler.params[i];
+            final LocalVariableDiscriminator discriminator = LocalVariableDiscriminator.parse(SurroundBinding.local(handler.method, i));
+            // MixinExtras 0.5.0 internal (pinned by UniMixins 0.3.1); recheck on bump
+            final Context context = InjectorUtils.getOrCreateLocalContext(target, node, this.info, type, discriminator.isArgsOnly());
+            String detail;
+            try {
+                slots[i - from] = discriminator.findLocal(context);
+                detail = slots[i - from] < 0 ? "no " + discriminator.toString(context) : null;
+            } catch (InvalidImplicitDiscriminatorException e) {
+                detail = e.getMessage();
+            }
+            if (detail != null) {
+                throw error(handler.ref() + " " + paramRef(handler.method, i) + " is @Surround.Local " + type.getClassName() + ", which matches no single local at the call: " + detail);
+            }
+        }
+        return slots;
+    }
+
+    private void prepare(Type[] expected, Type result, String against) {
+        if (this.exits == null) {
+            this.analyze(result);
+        }
+        this.checkArgPrefix(this.entry, expected, against);
+        for (Handler exit : this.exits.handlers) {
+            if (exit.role == Role.SKIPPED || exit.role == Role.RETURN || exit.handles) {
+                final Type declared = Type.getReturnType(exit.method.desc);
+                if (!declared.equals(result)) {
+                    throw error(exit.ref() + " must return " + result.getClassName() + " to match what it surrounds, not " + declared.getClassName());
+                }
+            }
+            if (exit.role == Role.RETURN && exit.leading == 1 && (exit.params.length == 0 || !exit.params[0].equals(result))) {
+                throw error(exit.ref() + " must declare the " + result.getClassName() + " result as its first parameter");
+            }
+            this.checkArgPrefix(exit, expected, against);
+        }
+        if (this.exits.skipped == null && this.exits.skipSlot >= 0 && result.getSize() > 0) {
+            throw error("can skip a " + result.getClassName() + " result but has no @Surround.Skipped" + this.forId() + " to supply it");
+        }
+    }
+
+    private void analyze(Type result) {
+        if (!this.returnType.equals(Type.VOID_TYPE)) {
+            throw error("must return void; carry state out with @Surround.Carry locals instead");
+        }
+        if (Bytecode.hasFlag(this.methodNode, Opcodes.ACC_ABSTRACT)) {
+            throw error("must not be abstract");
+        }
+        final Handler entry = new Handler(this.methodNode, Role.ENTRY, 0);
+        if (this.hasStrippedSugar()) {
+            throw error("one of its parameters is annotated @Local, @Share or @Cancellable" + SurroundBinding.SUGAR_HINT);
+        }
+        this.checkNoLocal(entry);
+        final AbstractInsnNode soleReturn = SurroundBinding.soleReturn(this.methodNode);
+
+        final Set<String> ids = new LinkedHashSet<>();
+        for (MethodNode method : this.mixin.getMixin().getClassNode(0).methods) {
+            final AnnotationNode surround = Annotations.get(method.visibleAnnotations, SurroundSpec.SURROUND);
+            if (surround == null) {
+                continue;
+            }
+            final String declared = Annotations.<String>getValue(surround, "id", "");
+            if (!ids.add(declared) && declared.equals(this.id)) {
+                throw error("duplicate @Surround " + describeId(this.id) + "; ids must be unique per mixin");
+            }
+        }
+        final List<Handler> handlers = new ArrayList<>();
+        for (MethodNode method : this.mixin.getClassNode().methods) {
+            Role role = null;
+            AnnotationNode annotation = null;
+            for (Role candidate : Role.EXITS) {
+                final AnnotationNode found = Annotations.get(method.visibleAnnotations, candidate.annotation);
+                if (found == null) {
+                    continue;
+                }
+                if (role != null) {
+                    throw error(exitRef(method) + " can be only one of @Surround.Catch, @Surround.Finally, @Surround.Skipped and @Surround.Return");
+                }
+                role = candidate;
+                annotation = found;
+            }
+            if (role == null) {
+                continue;
+            }
+            final String exitId = Annotations.<String>getValue(annotation, "value", "");
+            if (!ids.contains(exitId)) {
+                throw error(exitRef(method) + " " + noSurroundForId(exitId, ids));
+            }
+            if (this.id.equals(exitId)) {
+                handlers.add(this.exitHandler(this.own(method), role, role == Role.CATCH || role == Role.RETURN && result.getSize() > 0 ? 1 : 0));
+            }
+        }
+        handlers.sort(Comparator.comparing(handler -> handler.role));
+        boolean skipped = false;
+        for (int i = 0, n = handlers.size(); i < n; i++) {
+            final Role role = handlers.get(i).role;
+            skipped |= role == Role.SKIPPED;
+            if (i > 0 && role != Role.CATCH && role == handlers.get(i - 1).role) {
+                throw error("declares more than one @Surround." + role.name().charAt(0) + role.name().substring(1).toLowerCase(Locale.ROOT) + this.forId() + "; there can only be one");
+            }
+        }
+        final Handler[] sorted = handlers.toArray(new Handler[0]);
+        this.sortMostSpecificFirst(sorted);
+        final List<LocalVariableAnnotationNode> annotations = this.methodNode.visibleLocalVariableAnnotations;
+        final int[] kinds = annotations == null || annotations.isEmpty() ? null : SurroundBinding.kindsAtEnd(this.methodNode, soleReturn);
+        final int skipSlot = SurroundBinding.skipSlot(this.methodNode, kinds);
+        if (skipped && skipSlot < 0) {
+            throw error("has a @Surround.Skipped" + this.forId() + " but declares no @Surround.Skip local, so nothing is ever skipped");
+        }
+        final Type[] carried = SurroundBinding.bind(this.methodNode, kinds, sorted);
+        this.entry = entry;
+        this.exits = new Exits(sorted, skipSlot, carried);
+    }
+
+    // MixinExtras strips sugar params before parse; the annotation table can then be null.
+    private boolean hasStrippedSugar() {
+        final List<AnnotationNode>[] invisible = this.methodNode.invisibleParameterAnnotations;
+        if (invisible != null) {
+            return invisible.length != this.methodArgs.length;
+        }
+        final ClassInfo mixin = this.mixin.getClassInfo();
+        final String desc = this.methodNode.desc;
+        return mixin.findMethod(MethodNodeEx.getName(this.methodNode), desc, ClassInfo.INCLUDE_ALL) == null && mixin.findMethod(this.methodNode.name, desc, ClassInfo.INCLUDE_ALL) == null;
+    }
+
+    @Override
+    protected void sanityCheck(Target target, List<InjectionPoint> injectionPoints) {
+        super.sanityCheck(target, injectionPoints);
+        if (this.isInterface) {
+            throw error("cannot target an interface method " + target);
+        }
+        if (target.method.name.endsWith("init>")) {
+            throw error("cannot target the initializer " + target);
+        }
+        if (Bytecode.hasFlag(target.method, Opcodes.ACC_ABSTRACT) || Bytecode.hasFlag(target.method, Opcodes.ACC_NATIVE)) {
+            throw error("cannot target the abstract or native method " + target);
+        }
+    }
+
+    private Handler exitHandler(MethodNode method, Role role, int leading) {
+        final Handler exit = new Handler(method, role, leading);
+        if (exit.handles && !this.callSite) {
+            throw error(exit.ref() + " declares handle = true, which only applies when @Surround.at selects a call");
+        }
+        if (Bytecode.hasFlag(method, Opcodes.ACC_ABSTRACT)) {
+            throw error(exit.ref() + " must not be abstract");
+        }
+        if ((role == Role.FINALLY || role == Role.CATCH && !exit.handles) && !Type.getReturnType(method.desc).equals(Type.VOID_TYPE)) {
+            throw error(exit.ref() + " must return void; an exit handler cannot suppress or replace anything");
+        }
+        if (Bytecode.isStatic(method) != this.isStatic) {
+            throw error(exit.ref() + " must be " + (this.isStatic ? "static" : "non-static") + " to match the entry handler" + this.forId());
+        }
+        if (role == Role.CATCH) {
+            if (exit.params.length == 0) {
+                throw error(exit.ref() + " must declare the Throwable it catches as its first parameter");
+            }
+            final Type caught = exit.caught();
+            if (caught.getSort() != Type.OBJECT || !SurroundSpec.THROWABLE.equals(caught.getInternalName()) && !extendsClass(caught, SurroundSpec.THROWABLE)) {
+                throw error(exit.ref() + " " + paramRef(method, 0) + " catches " + caught.getClassName() + ", which is not a java.lang.Throwable subtype");
+            }
+        }
+        this.checkNoLocal(exit);
+        return exit;
+    }
+
+    private void checkNoLocal(Handler handler) {
+        if (!this.callSite && handler.localStart < handler.carryStart) {
+            throw error(handler.ref() + " " + paramRef(handler.method, handler.localStart) + " is @Surround.Local, which only applies when @Surround.at selects a call");
+        }
+    }
+
+    private void checkArgPrefix(Handler handler, Type[] expected, String against) {
+        final Type[] params = handler.params;
+        if (handler.localStart - handler.leading > expected.length) {
+            throw error(handler.ref() + " has more parameters than " + against);
+        }
+        for (int i = handler.leading, arg = 0; i < handler.localStart; i++, arg++) {
+            if (params[i].equals(expected[arg]) || this.callSite && isAssignable(params[i], expected[arg])) {
+                continue;
+            }
+            throw error(handler.ref() + " " + paramRef(handler.method, i) + " is " + params[i].getClassName() + ", which does not match the " + expected[arg].getClassName() + " operand of " + against);
+        }
+    }
+
+    private static boolean isAssignable(Type param, Type operand) {
+        if (param.getSort() != Type.OBJECT || operand.getSort() != Type.OBJECT && operand.getSort() != Type.ARRAY) {
+            return false;
+        }
+        if (SurroundSpec.OBJECT.equals(param.getInternalName())) {
+            return true;
+        }
+        if (operand.getSort() != Type.OBJECT) {
+            return false;
+        }
+        final ClassInfo info = ClassInfo.forName(operand.getInternalName());
+        return info != null && info.findSuperClass(param.getInternalName(), Traversal.ALL, true) != null;
+    }
+
+    private void sortMostSpecificFirst(Handler[] exits) {
+        for (int k = 1; k < exits.length && exits[k].role == Role.CATCH; k++) {
+            final Handler exit = exits[k];
+            final Type caught = exit.caught();
+            int at = k;
+            for (int i = 0; i < k; i++) {
+                final Type other = exits[i].caught();
+                if (caught.equals(other)) {
+                    throw error(exit.ref() + " is a second @Surround.Catch for " + caught.getClassName() + this.forId() + "; each type may be caught once");
+                }
+                if (at == k && extendsClass(caught, other.getInternalName())) {
+                    at = i;
+                }
+            }
+            System.arraycopy(exits, at, exits, at + 1, k - at);
+            exits[at] = exit;
+        }
+    }
+
+    private static boolean extendsClass(Type type, String superName) {
+        final ClassInfo info = ClassInfo.forName(type.getInternalName());
+        return info != null && info.hasSuperClass(superName);
+    }
+
+    private MethodNode own(MethodNode exit) {
+        final MethodNode method = Bytecode.findMethod(this.classNode, exit.name, exit.desc);
+        if (method == null) {
+            throw new IllegalStateException(exit.name + exit.desc + " is missing from " + this.classNode.name);
+        }
+        if (!this.mixin.getClassName().equals(SurroundSpec.mergedBy(method))) {
+            throw error(exitRef(exit) + " collides with " + exit.name + exit.desc + " in " + this.classNode.name + ", which is " + SurroundSpec.describeOwner(method));
+        }
+        return method;
+    }
+
+    private String forId() {
+        return this.id.isEmpty() ? "" : " for id '" + this.id + "'";
+    }
+
+    private static String describeId(String id) {
+        return id.isEmpty() ? "the default id" : "id '" + id + "'";
+    }
+
+    static String noSurroundForId(String id, Collection<String> declared) {
+        final StringJoiner ids = new StringJoiner(", ", "; declared ids are ", "").setEmptyValue("; this mixin has no @Surround at all");
+        for (String other : declared) {
+            ids.add(describeId(other));
+        }
+        return "refers to " + describeId(id) + " but no @Surround in this mixin declares it" + ids;
+    }
+
+    private InvalidInjectionException error(String message) {
+        return new InvalidInjectionException(this.info, "@Surround " + this.info.getMethodName() + " " + message);
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundRejection.java

@@ -0,0 +1,10 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+final class SurroundRejection extends RuntimeException {
+
+    private static final long serialVersionUID = 1L;
+
+    SurroundRejection(String message) {
+        super(message, null, false, false);
+    }
+}

experimental-surround/runtime/src/main/java/com/gtnewhorizons/angelica/experimental/surround/SurroundSpec.java

@@ -0,0 +1,33 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.spongepowered.asm.lib.Type;
+import org.spongepowered.asm.lib.tree.AnnotationNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.mixin.transformer.meta.MixinMerged;
+import org.spongepowered.asm.util.Annotations;
+
+interface SurroundSpec {
+
+    String SURROUND = Type.getDescriptor(Surround.class);
+    String CATCH = Type.getDescriptor(Surround.Catch.class);
+    String FINALLY = Type.getDescriptor(Surround.Finally.class);
+    String CARRY = Type.getDescriptor(Surround.Carry.class);
+    String SKIP = Type.getDescriptor(Surround.Skip.class);
+    String SKIPPED = Type.getDescriptor(Surround.Skipped.class);
+    String RETURN = Type.getDescriptor(Surround.Return.class);
+    String LOCAL = Type.getDescriptor(Surround.Local.class);
+    String MIXIN_MERGED = Type.getDescriptor(MixinMerged.class);
+    String OBJECT = Type.getInternalName(Object.class);
+    String THROWABLE = Type.getInternalName(Throwable.class);
+    String THROWABLE_DESC = Type.getDescriptor(Throwable.class);
+
+    static String mergedBy(MethodNode method) {
+        final AnnotationNode merged = Annotations.get(method.visibleAnnotations, MIXIN_MERGED);
+        return merged == null ? null : Annotations.<String>getValue(merged, "mixin");
+    }
+
+    static String describeOwner(MethodNode method) {
+        final String owner = mergedBy(method);
+        return owner == null ? "not merged from a mixin" : "merged from " + owner;
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/CallSiteTest.java

@@ -0,0 +1,80 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.Entity;
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.ReportedException;
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.spongepowered.asm.lib.tree.AbstractInsnNode;
+import org.spongepowered.asm.lib.tree.MethodInsnNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.lib.tree.TryCatchBlockNode;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.List;
+
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.CALL;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.call;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.method;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.transformedNode;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class CallSiteTest {
+
+    @BeforeEach
+    void resetTrace() {
+        Trace.reset();
+    }
+
+    @Test
+    void aRedirectedCallInsideJavacTryCatchesRethrowsInsideTheEnclosingTry() throws Exception {
+        assertEquals(true, call(CALL, "render", new Entity("pig"), 1.0d, 2.0d, 3.0d, 0.5f, 0.25f, true));
+        final Entity creeper = new Entity("creeper");
+        creeper.explode = true;
+        final InvocationTargetException thrown = assertThrows(InvocationTargetException.class, () -> call(CALL, "render", creeper, 1.0d, 2.0d, 3.0d, 0.5f, 0.25f, false));
+
+        final ReportedException outer = (ReportedException) thrown.getCause();
+        assertEquals("Rendering entity (outer)", outer.getMessage());
+        assertEquals("Rendering entity in world", outer.getCause().getMessage());
+        assertSame(RuntimeException.class, outer.getCause().getCause().getClass());
+        assertEquals("gpu", outer.getCause().getCause().getMessage());
+        Trace.assertEvents("enterDoRender pig 1", "redirect pig", "doRender pig 1.0 0.25", "exitDoRender pig 1", "shadow pig", "boundingBox pig", "enterDoRender creeper 2", "redirect creeper", "doRender creeper 1.0 0.25", "caughtDoRender creeper gpu 2", "exitDoRender creeper 2");
+    }
+
+    @Test
+    void theSurroundedCallMatchesTheGoldens() {
+        MixinTestBootstrap.assertGolden(CALL, "valueSkip", "call-skip");
+        MixinTestBootstrap.assertGolden(CALL, "valueBelow", "call-handle");
+    }
+
+    @Test
+    void nestedSurroundsShareOneCallAndOrderTheirTryRangesInnerFirst() {
+        final MethodNode target = method(transformedNode(CALL), "innerSkipOuterReturn");
+        int calls = 0;
+        for (AbstractInsnNode insn : target.instructions.toArray()) {
+            calls += insn instanceof MethodInsnNode m && m.name.equals("twice") ? 1 : 0;
+        }
+        assertEquals(1, calls);
+        final List<TryCatchBlockNode> blocks = target.tryCatchBlocks;
+        boolean nests = false;
+        for (int i = 0; i < blocks.size(); i++) {
+            for (int j = 0; j < blocks.size(); j++) {
+                final boolean encloses = encloses(target, blocks.get(i), blocks.get(j));
+                nests |= encloses;
+                assertTrue(!encloses || i > j, "block " + i + " encloses block " + j);
+            }
+        }
+        assertTrue(nests, "no try block encloses another");
+    }
+
+    private static boolean encloses(MethodNode target, TryCatchBlockNode outer, TryCatchBlockNode inner) {
+        final int outerStart = target.instructions.indexOf(outer.start);
+        final int outerEnd = target.instructions.indexOf(outer.end);
+        final int innerStart = target.instructions.indexOf(inner.start);
+        final int innerEnd = target.instructions.indexOf(inner.end);
+        return outerStart <= innerStart && innerEnd <= outerEnd && (outerStart < innerStart || innerEnd < outerEnd);
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/CompositionTest.java

@@ -0,0 +1,134 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import com.llamalad7.mixinextras.utils.MixinInternals;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.spongepowered.asm.lib.Opcodes;
+import org.spongepowered.asm.lib.Type;
+import org.spongepowered.asm.lib.tree.ClassNode;
+import org.spongepowered.asm.lib.tree.InsnNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.mixin.transformer.ext.Extensions;
+import org.spongepowered.asm.mixin.transformer.ext.IExtension;
+import org.spongepowered.asm.mixin.transformer.meta.MixinMerged;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Stream;
+
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.WRAP;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.of;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.scenario;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class CompositionTest {
+
+    private static final Set<String> RUN_BEFORE = Set.of("LateInjectionApplicatorExtension", "SugarPostProcessingExtension", "WrapMethodApplicatorExtension");
+    private static final String CHECK_CLASS = "ExtensionCheckClass";
+
+    @BeforeEach
+    void resetTrace() {
+        Trace.reset();
+    }
+
+    private static Object wrap(String name, Object... args) throws Exception {
+        return MixinTestBootstrap.call(WRAP, name, args);
+    }
+
+    static Stream<Arguments> mixinExtras() {
+        return Stream.of(
+            scenario(WRAP, "the surround is outside @WrapMethod", "wrapped", of(3), of(6), "entry 3", "wrap-before 3", "body 3", "wrap-after 6", "finally"),
+            scenario(WRAP, "the entry sees the operand before @WrapOperation shifts it", "originalOperands", of(5), of(210), "enter 5", "wrap 5", "twice 105", "exit 5"));
+    }
+
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("mixinExtras")
+    @Tag("mixinextras")
+    void mixinExtras(String method, String target, Object[] inputs, Object[] outputs, String[] events) throws Exception {
+        MixinTestBootstrap.assertScenario(target, method, inputs, outputs, events);
+    }
+
+    @Test
+    @Tag("mixinextras")
+    void aLocalFollowsTheBodyWhenAShareShiftsItsSlot() throws Exception {
+        assertEquals(10, wrap("shifted", 3));
+        Trace.assertEvents("wrap 3", "enterShifted 4 4 L4", "twice 4", "exitShifted 4 L4");
+        MethodNode body = null;
+        for (MethodNode method : MixinTestBootstrap.transformedNode(WRAP).methods) {
+            body = method.name.startsWith("shifted$") ? method : body;
+        }
+        assertTrue(body != null && body.desc.startsWith("(IL"), "the body did not move and gain the share");
+    }
+
+    @Test
+    @Tag("mixinextras")
+    void ourExtensionRunsAfterMixinExtrasAndBeforeCheckClass() throws Exception {
+        MixinTestBootstrap.transformer();
+        final SurroundApplicatorExtension ours = SurroundApplicatorExtension.instance();
+        MixinTestBootstrap.transform(WRAP);
+        final Extensions extensions = MixinInternals.getExtensions();
+        for (List<IExtension> list : List.of(extensions.getExtensions(), extensions.getActiveExtensions())) {
+            final int at = assertSlot(list, ours);
+            for (String name : RUN_BEFORE) {
+                final int index = names(list).indexOf(name);
+                assertTrue(index >= 0 && index < at, names(list).toString());
+                assertTrue(list.get(index).getClass().getName().startsWith("com.llamalad7.mixinextras."));
+            }
+        }
+        assertCheckClassActiveUnderVerify(extensions);
+    }
+
+    @Test
+    void anUnrenamedSurroundHandlerIsFatal() {
+        final String mixin = "com.example.mixin.MixinLate";
+        final MethodNode method = new MethodNode(Opcodes.ACC_PRIVATE, "surround$enter", "()V", null, null);
+        method.instructions.add(new InsnNode(Opcodes.RETURN));
+        method.visitAnnotation(Type.getDescriptor(Surround.class), true).visitEnd();
+        method.visitAnnotation(Type.getDescriptor(MixinMerged.class), true).visit("mixin", mixin);
+        final ClassNode target = new ClassNode();
+        target.version = Opcodes.V1_8;
+        target.access = Opcodes.ACC_PUBLIC;
+        target.name = "com/example/Target";
+        target.superName = "java/lang/Object";
+        target.methods.add(method);
+
+        final String message = assertThrows(IllegalStateException.class, () -> SurroundApplicatorExtension.checkHandlersRenamed(target, Set.of())).getMessage();
+        assertTrue(message.startsWith("surround$enter()V in com/example/Target (merged from " + mixin + ") carries @Surround but was never parsed as an injector"), message);
+        assertTrue(message.contains("SurroundBootstrap.init() must run before"), message);
+    }
+
+    private static void assertCheckClassActiveUnderVerify(Extensions extensions) {
+        final List<String> active = names(extensions.getActiveExtensions());
+        assertEquals(Boolean.getBoolean("mixin.debug.verify"), active.contains(CHECK_CLASS), active.toString());
+    }
+
+    private static List<String> names(List<IExtension> list) {
+        final List<String> names = new ArrayList<>(list.size());
+        for (IExtension extension : list) {
+            names.add(extension.getClass().getSimpleName());
+        }
+        return names;
+    }
+
+    private static int assertSlot(List<IExtension> list, IExtension ours) {
+        final List<String> names = names(list);
+        assertEquals(list.indexOf(ours), list.lastIndexOf(ours), "registered twice: " + names);
+        final int at = list.indexOf(ours);
+        assertTrue(at >= 0, "missing: " + names);
+        for (String after : names.subList(at + 1, names.size())) {
+            assertFalse(RUN_BEFORE.contains(after), after + " runs after us: " + names);
+        }
+        final int check = names.indexOf(CHECK_CLASS);
+        assertTrue(check < 0 || check > at, CHECK_CLASS + " runs before us: " + names);
+        return at;
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/LocalSortingTransformer.java

@@ -0,0 +1,36 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import makamys.mixingasm.api.MixinSafeTransformer;
+import net.minecraft.launchwrapper.IClassTransformer;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.commons.LocalVariablesSorter;
+
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+@MixinSafeTransformer
+public final class LocalSortingTransformer implements IClassTransformer {
+
+    public static final Set<String> SEEN = ConcurrentHashMap.newKeySet();
+
+    @Override
+    public byte[] transform(String name, String transformedName, byte[] bytes) {
+        SEEN.add(transformedName);
+        if (bytes == null || ((bytes[6] & 0xFF) << 8 | bytes[7] & 0xFF) > Opcodes.V1_8) {
+            return bytes;
+        }
+        final ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS);
+        new ClassReader(bytes).accept(new ClassVisitor(Opcodes.ASM5, writer) {
+            @Override
+            public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
+                return new LocalVariablesSorter(Opcodes.ASM5, access, desc, super.visitMethod(access, name, desc, signature, exceptions)) {
+                };
+            }
+        }, ClassReader.EXPAND_FRAMES);
+        return writer.toByteArray();
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/MixinTestBootstrap.java

@@ -0,0 +1,277 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import com.llamalad7.mixinextras.MixinExtrasBootstrap;
+import net.minecraft.launchwrapper.Launch;
+import net.minecraft.launchwrapper.LaunchClassLoader;
+import org.junit.jupiter.api.Named;
+import org.junit.jupiter.params.provider.Arguments;
+import org.spongepowered.asm.launch.MixinBootstrap;
+import org.spongepowered.asm.lib.ClassReader;
+import org.spongepowered.asm.lib.tree.ClassNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+import org.spongepowered.asm.lib.util.Textifier;
+import org.spongepowered.asm.lib.util.TraceClassVisitor;
+import org.spongepowered.asm.mixin.EnvironmentStateTweaker;
+import org.spongepowered.asm.mixin.MixinEnvironment;
+import org.spongepowered.asm.mixin.Mixins;
+import org.spongepowered.asm.mixin.transformer.IMixinTransformer;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.fail;
+
+public final class MixinTestBootstrap {
+
+    private MixinTestBootstrap() {
+    }
+
+    private static final class Holder {
+
+        static final IMixinTransformer TRANSFORMER = boot();
+    }
+
+    public static IMixinTransformer transformer() {
+        return Holder.TRANSFORMER;
+    }
+
+    private static final Map<String, byte[]> TRANSFORMED = new HashMap<>();
+    private static final Map<String, Class<?>> DEFINED = new HashMap<>();
+
+    public static byte[] transformedBytes(String binaryName) {
+        return TRANSFORMED.computeIfAbsent(binaryName, name -> transformer().transformClassBytes(name, name, read(name)));
+    }
+
+    public static Class<?> transform(String binaryName) {
+        return DEFINED.computeIfAbsent(binaryName, name -> define(name, transformedBytes(name)));
+    }
+
+    public static Object call(String target, String name, Object... args) throws Exception {
+        final Class<?> owner = transform(target);
+        for (Method method : owner.getMethods()) {
+            if (method.getName().equals(name) && method.getParameterCount() == args.length) {
+                final boolean isStatic = Modifier.isStatic(method.getModifiers());
+                return method.invoke(isStatic ? null : owner.getDeclaredConstructor().newInstance(), args);
+            }
+        }
+        throw new AssertionError("no " + name + " in " + target);
+    }
+
+    static final String WHOLE = "com.gtnewhorizons.angelica.experimental.surround.integration.WholeTarget";
+    static final String CALL = "com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget";
+    static final String WRAP = "com.gtnewhorizons.angelica.experimental.surround.integration.WrapTarget";
+
+    static ClassNode transformedNode(String target) {
+        return parse(transformedBytes(target));
+    }
+
+    static ClassNode originalNode(String binaryName) {
+        return parse(read(binaryName));
+    }
+
+    private static ClassNode parse(byte[] bytes) {
+        final ClassNode node = new ClassNode();
+        new ClassReader(bytes).accept(node, 0);
+        return node;
+    }
+
+    static MethodNode method(ClassNode node, String name) {
+        for (MethodNode method : node.methods) {
+            if (method.name.equals(name)) {
+                return method;
+            }
+        }
+        throw new AssertionError("no method " + name + " in " + node.name);
+    }
+
+    static void assertGolden(String target, String method, String golden) {
+        final ClassNode full = transformedNode(target);
+        final ClassNode slim = new ClassNode();
+        slim.visit(full.version, full.access, full.name, null, full.superName, null);
+        slim.methods.add(method(full, method));
+        for (MethodNode candidate : full.methods) {
+            if (candidate.name.startsWith(method + "$surround")) {
+                slim.methods.add(candidate);
+            }
+        }
+        final StringWriter out = new StringWriter();
+        slim.accept(new TraceClassVisitor(null, new Textifier(), new PrintWriter(out)));
+        final String stripped = out.toString().replaceAll("(?m)^ *LINENUMBER \\d+ L\\d+\\r?\\n", "");
+        final String actual = normalize(stripped.replaceAll("\\b([a-z]+)\\$[a-z]{3,}[0-9a-f]{3,}\\$", "$1\\$\\$").replaceAll("\\bmd[0-9a-f]+\\$jvmdowngrader\\$", "md\\$jvmdowngrader\\$"));
+        final Path file = Paths.get(System.getProperty("surround.golden.dir")).resolve(golden + ".asm");
+        try {
+            if (!Files.exists(file)) {
+                Files.write(file, actual.getBytes(StandardCharsets.UTF_8));
+                fail("Created golden " + file + ". Inspect it, then re-run.");
+            }
+            assertEquals(normalize(new String(Files.readAllBytes(file), StandardCharsets.UTF_8)), actual, "output changed; inspect the diff before updating " + file);
+        } catch (IOException e) {
+            throw new AssertionError(e);
+        }
+    }
+
+    private static String normalize(String text) {
+        final StringBuilder result = new StringBuilder();
+        for (String line : text.replace("\r\n", "\n").split("\n", -1)) {
+            result.append(line.replaceAll("\\s+$", "").replaceAll("(\\$jvmdowngrader\\$concat\\$[\\w$]*?\\$\\d+)\\$[0-9a-f]+\\b", "$1")).append('\n');
+        }
+        return result.toString().trim() + "\n";
+    }
+
+    static final Object VOID = null;
+
+    static Arguments scenario(String target, String name, String method, Object[] inputs, Object[] outputs, String... events) {
+        return Arguments.of(Named.of(name, method), target, inputs, outputs, events);
+    }
+
+    static Object[] of(Object... values) {
+        return values;
+    }
+
+    static List<Object> args(Object... values) {
+        return Arrays.asList(values);
+    }
+
+    static void assertScenario(String target, String method, Object[] inputs, Object[] outputs, String[] events) throws Exception {
+        Trace.reset();
+        for (int i = 0; i < inputs.length; i++) {
+            final Object[] args = inputs[i] instanceof List<?> list ? list.toArray() : new Object[]{inputs[i]};
+            if (outputs[i] instanceof Class<?> type && Throwable.class.isAssignableFrom(type)) {
+                final InvocationTargetException thrown = assertThrows(InvocationTargetException.class, () -> call(target, method, args));
+                assertEquals(outputs[i], thrown.getCause().getClass());
+            } else {
+                assertEquals(outputs[i], call(target, method, args));
+            }
+        }
+        Trace.assertEvents(events);
+    }
+
+    private static final boolean MIXINEXTRAS = Boolean.getBoolean("surround.test.mixinextras");
+    private static final boolean ADDITIONS_FIRST = Boolean.getBoolean("surround.test.additionsFirst");
+    private static final boolean OBF = Boolean.getBoolean("surround.test.obf");
+
+    private static IMixinTransformer boot() {
+        Launch.blackboard = new HashMap<>();
+        Launch.classLoader = new LaunchClassLoader(classpath());
+        if (OBF) {
+            Launch.classLoader.addTransformerExclusion(LocalSortingTransformer.class.getName());
+            Launch.classLoader.registerTransformer(LocalSortingTransformer.class.getName());
+            if (Launch.classLoader.getTransformers().stream().noneMatch(t -> t.getClass().getName().equals(LocalSortingTransformer.class.getName()))) {
+                throw new IllegalStateException("LocalSortingTransformer was not registered");
+            }
+        }
+
+        if (!MIXINEXTRAS) {
+            SurroundBootstrap.init();
+        }
+        MixinBootstrap.init();
+        if (MIXINEXTRAS) {
+            if (ADDITIONS_FIRST) {
+                SurroundBootstrap.init();
+            }
+            MixinExtrasBootstrap.init();
+            if (!ADDITIONS_FIRST) {
+                SurroundBootstrap.init();
+            }
+        }
+        Mixins.addConfiguration("mixins.surround.test.json");
+        if (!OBF) {
+            Mixins.addConfiguration(RejectionCases.compileConfig(MIXINEXTRAS));
+        }
+        if (MIXINEXTRAS) {
+            Mixins.addConfiguration("mixins.surround.mixinextras.test.json");
+        }
+
+        final EnvironmentStateTweaker tweaker = new EnvironmentStateTweaker();
+        tweaker.injectIntoClassLoader(Launch.classLoader);
+        tweaker.getLaunchArguments();
+
+        return active();
+    }
+
+    private static IMixinTransformer active() {
+        final Object transformer = MixinEnvironment.getCurrentEnvironment().getActiveTransformer();
+        if (!(transformer instanceof IMixinTransformer mixinTransformer)) {
+            throw new IllegalStateException("no active mixin transformer, got " + transformer);
+        }
+        return mixinTransformer;
+    }
+
+    private static URL[] classpath() {
+        final List<URL> urls = new ArrayList<>();
+        for (String entry : System.getProperty("java.class.path").split(File.pathSeparator)) {
+            try {
+                urls.add(new File(entry).toURI().toURL());
+            } catch (MalformedURLException e) {
+                throw new IllegalStateException(entry, e);
+            }
+        }
+        return urls.toArray(new URL[urls.size()]);
+    }
+
+    static byte[] read(String binaryName) {
+        try {
+            final byte[] bytes = Launch.classLoader.getClassBytes(binaryName);
+            if (bytes == null) {
+                throw new IllegalStateException("missing " + binaryName);
+            }
+            return bytes;
+        } catch (IOException e) {
+            throw new IllegalStateException(binaryName, e);
+        }
+    }
+
+    private static Class<?> define(String name, byte[] bytes) {
+        try {
+            return new DefiningClassLoader(name, bytes).loadClass(name);
+        } catch (ClassNotFoundException e) {
+            throw new AssertionError(e);
+        }
+    }
+
+    private static final class DefiningClassLoader extends ClassLoader {
+
+        private final String name;
+        private final byte[] bytes;
+
+        DefiningClassLoader(String name, byte[] bytes) {
+            super(MixinTestBootstrap.class.getClassLoader());
+            this.name = name;
+            this.bytes = bytes;
+        }
+
+        @Override
+        protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
+            if (!this.name.equals(name)) {
+                return super.loadClass(name, resolve);
+            }
+            Class<?> loaded = findLoadedClass(name);
+            if (loaded == null) {
+                loaded = defineClass(name, this.bytes, 0, this.bytes.length);
+            }
+            if (resolve) {
+                resolveClass(loaded);
+            }
+            return loaded;
+        }
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/RejectionCases.java

@@ -0,0 +1,182 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import net.minecraft.launchwrapper.Launch;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+final class RejectionCases {
+
+    static final String PACKAGE = "rejection";
+    static final String CONFIG = "mixins.surround.rejection.test.json";
+    static final String ABS = "at = @At(value = \"INVOKE\", target = \"Ljava/lang/Math;abs(I)I\")";
+    static final String WHOLE_ENTRY = "@Surround(method = \"run\") private void invalid$enter(int a) {}";
+    static final String FINALLY = " @Surround.Finally private void invalid$always() {}";
+    static final String RUN = cls("public int run(int a) { return Math.abs(a); }");
+    static final String IN_NEW = cls("public int run(int a) { return new StringBuilder(Math.abs(a)).length(); }");
+
+    static final Case[] CASES = {
+        new Case("Initializer", "@Surround invalid$enter cannot target the initializer", RUN, mixin("@Surround(method = \"<init>()V\") private void invalid$enter() {}")),
+        new Case("Staticness", "must be non-static to match the entry handler", RUN, mixin(WHOLE_ENTRY + " @Surround.Finally private static void invalid$always() {}")),
+        new Case("CarriedThrowable", "cannot mark its caught Throwable parameter @Surround.Carry", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) {" + " @Surround.Carry Throwable state = null; }" + " @Surround.Catch private void invalid$caught(@Surround.Carry Throwable e) {}")),
+        new Case("LocalCall", "is @Surround.Local java.lang.String, which matches no single local at the call", RUN, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a, @Surround.Local String s) {}")),
+        new Case("HandleInsideNew", "declares handle = true, but the call is inside a constructor call's arguments", IN_NEW, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a) {}" + " @Surround.Catch(handle = true) private int invalid$caught(Throwable error) { return 0; }")),
+        new Case("SkippedRequired", "can skip a int result but has no @Surround.Skipped", RUN, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a) {" + " @Surround.Skip boolean skip = a > 0; }")),
+        new Case("Shift", "@Surround invalid$enter has @At(\"INVOKE\") with a non-default shift or by, which moves the match off the call", RUN, mixin("@Surround(method = \"run\", at = @At(value = \"INVOKE\", target = \"Ljava/lang/Math;abs(I)I\", shift = At.Shift.AFTER)) private void invalid$enter() {}")),
+        new Case("AbstractTarget", "cannot target the abstract or native method", "public abstract class $T { public abstract int run(int a); }", "@Mixin(value = $T.class, remap = false) public abstract class $M {" + " @Surround(method = \"run\") private void invalid$enter(int a) {} }"),
+        new Case("InitAt", "at must select a method call, not the constructor call java/lang/StringBuilder.<init>()V", cls("public Object run(int a) { return new StringBuilder(); }"), mixin("@Surround(method = \"run\", at = @At(value = \"INVOKE\", target = \"Ljava/lang/StringBuilder;<init>()V\")) private void invalid$enter() {}")),
+        new Case("CatchingEntry", "must not catch exceptions when it surrounds a call inside a constructor call's arguments", IN_NEW, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a) {" + " try { Math.abs(a); } catch (RuntimeException e) { Math.abs(0); } }" + FINALLY)),
+        new Case("TooManyOperands", "entry handler has more parameters than call java/lang/Math.abs(I)I", RUN, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a, int b) {}")),
+        new Case("SkipNotAssigned", "has a @Surround.Skip local in slot 2 that is not definitely assigned", cls("public void run(int a) {}"), mixin("@Surround(method = \"run\") private void invalid$enter(int a) {" + " @Surround.Skip boolean skip; if (a > 0) { skip = true; String.valueOf(a); } }")),
+        new Case("Collision", "exit handler 'surround$exit' collides with surround$exit()V in " + PACKAGE + "/Collision, which is merged from " + PACKAGE + ".mixin.CollisionMixin2", RUN, "@Mixin(value = $T.class, priority = 900, remap = false) public class $M {" + " @Surround(method = \"run\") private void surround$enter(int a) {}" + " @Surround.Finally private void surround$exit() {} }", "@Mixin(value = $T.class, priority = 1100, remap = false) public class $M {" + " private void surround$exit() {} }"),
+        new Case("MultipleRoles", "can be only one of @Surround.Catch, @Surround.Finally, @Surround.Skipped and @Surround.Return", RUN, mixin(WHOLE_ENTRY + " @Surround.Catch @Surround.Finally private void invalid$exit(Throwable e) {}")),
+        new Case("DuplicateId", "duplicate @Surround the default id; ids must be unique per mixin", RUN, mixin(WHOLE_ENTRY + " @Surround(method = \"run\") private void invalid$enter2(int a) {}")),
+        new Case("OrphanExit", "no @Surround in this mixin declares it", RUN, mixin(WHOLE_ENTRY + " @Surround.Finally(\"typo\") private void invalid$always() {}")),
+        new Case("CarryOnEntryParameter", "only the entry handler's own locals can be carried", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(@Surround.Carry int a) {}")),
+        new Case("CarryIdNotDeclared", "asks for the carried local 'frist'", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Carry(\"first\") int first = 1; }" + " @Surround.Finally private void invalid$always(@Surround.Carry(\"frist\") int typo) {}")),
+        new Case("NoCarryOfKind", "matches no carried local of that kind", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Carry int count = 1; }" + " @Surround.Finally private void invalid$always(@Surround.Carry float missing) {}")),
+        new Case("AmbiguousCarry", "matches 2 carried locals of that kind", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Carry int first = 1; @Surround.Carry int second = 2; }" + " @Surround.Finally private void invalid$always(@Surround.Carry int either) {}")),
+        new Case("CarryReadAsDifferentType", "but another exit handler reads it as java.lang.String", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Carry Object value = null; }" + " @Surround.Catch private void invalid$caught(java.io.IOException e, @Surround.Carry String value) {}" + " @Surround.Finally private void invalid$always(@Surround.Carry Integer value) {}")),
+        new Case("AmbiguousWideLocal", "shares its scope with another", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Carry long first; long second; try { first = a; second = a + 1L; } catch (RuntimeException e) { throw e; } }")),
+        new Case("DuplicateCarryId", "declares two @Surround.Carry locals named 'x'", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Carry(\"x\") int first = 1; @Surround.Carry(\"x\") long second = 2L; }")),
+        new Case("CarryInsideType", "@Surround.Carry must annotate the local itself, not part of its type", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { java.util.List<@Surround.Carry String> l = null; }")),
+        new Case("DuplicateSkip", "declares two @Surround.Skip locals", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Skip boolean first = a > 0; @Surround.Skip boolean second = a < 0; }")),
+        new Case("SkipNotIntLike", "it must be boolean or int-like", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { @Surround.Skip long skip = a; }")),
+        new Case("SkippedWithoutSkip", "but declares no @Surround.Skip local, so nothing is ever skipped", RUN, mixin(WHOLE_ENTRY + " @Surround.Skipped private int invalid$skipped(int a) { return 0; }")),
+        new Case("CarryScopedEarly", "goes out of scope before the entry handler ends", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) {" + " { @Surround.Carry int scoped = a; String.valueOf(scoped); } int reused = a + 1; String.valueOf(reused); }" + " @Surround.Finally private void invalid$always(@Surround.Carry int value) {}")),
+        new Case("EarlyReturn", "every path falls through to its end", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) {" + " if (a > 0) { return; } String.valueOf(a); }" + FINALLY)),
+        new Case("PartialAfterInt", "is not definitely assigned when the entry handler ends", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) {" + " { int tmp = a + 5; String.valueOf(tmp); }" + " @Surround.Carry int flag; if (a > 0) { flag = 1; String.valueOf(flag); } }" + " @Surround.Finally private void invalid$always(@Surround.Carry int flag) {}")),
+        new Case("AssignsParameter", "must not assign its parameters", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { a = a + 1; }" + FINALLY)),
+        new Case("LocalOnWholeMethod", "is @Surround.Local, which only applies when @Surround.at selects a call", RUN, mixin(WHOLE_ENTRY + " @Surround.Finally private void invalid$always(@Surround.Local int b) {}")),
+        new Case("IncrementsParameter", "must not assign its parameters", RUN, mixin("@Surround(method = \"run\") private void invalid$enter(int a) { a++; }" + FINALLY)),
+        new Case("NonCallAt", "@Surround invalid$enter has @At(\"HEAD\"), which does not select a method call", RUN, mixin("@Surround(method = \"run\", at = @At(\"HEAD\")) private void invalid$enter() {}")),
+        new Case("CancellableExit", "parameter 0 ('ci') of 'invalid$always' is annotated @Cancellable, which a @Surround handler cannot resolve", RUN, mixin(WHOLE_ENTRY + " @Surround.Finally private void invalid$always(@Cancellable Object ci) {}")),
+        new Case("DuplicateFinally", "declares more than one @Surround.Finally", RUN, mixin(WHOLE_ENTRY + FINALLY + " @Surround.Finally private void invalid$always2() {}")),
+        new Case("ReturnWrongType", "must return java.lang.String to match what it surrounds, not int", cls("public String run(String s) { return s.trim(); }"), mixin("@Surround(method = \"run\", at = @At(value = \"INVOKE\", target = \"Ljava/lang/String;trim()Ljava/lang/String;\")) private void invalid$enter(String s) {}" + " @Surround.Return private int invalid$ret(int result) { return result; }")),
+        new Case("ReturnResultNotFirst", "must declare the int result as its first parameter", RUN, mixin(WHOLE_ENTRY + " @Surround.Return private int invalid$ret(String wrong) { return 0; }")),
+        new Case("ReturnCarriedResult", "cannot mark its result parameter @Surround.Carry", RUN, mixin(WHOLE_ENTRY + " @Surround.Return private int invalid$ret(@Surround.Carry int result) { return result; }")),
+        new Case("NonVoidFinally", "must return void; an exit handler cannot suppress or replace anything", RUN, mixin(WHOLE_ENTRY + " @Surround.Finally private int invalid$always() { return 1; }")),
+        new Case("NonVoidEntry", "must return void; carry state out with @Surround.Carry locals instead", RUN, mixin("@Surround(method = \"run\") private long invalid$enter(int a) { return 0L; }")),
+        new Case("CatchNotThrowable", "parameter 0 ('notAnError') catches java.lang.String, which is not a java.lang.Throwable subtype", RUN, mixin(WHOLE_ENTRY + " @Surround.Catch private void invalid$caught(String notAnError) {}")),
+        new Case("DuplicateCatch", "is a second @Surround.Catch for java.io.IOException", RUN, mixin(WHOLE_ENTRY + " @Surround.Catch private void invalid$first(java.io.IOException e) {} @Surround.Catch private void invalid$second(java.io.IOException e) {}")),
+        new Case("CatchWithoutParameters", "must declare the Throwable it catches as its first parameter", RUN, mixin(WHOLE_ENTRY + " @Surround.Catch private void invalid$caught() {}")),
+        new Case("AbstractEntry", "must not be abstract", RUN, "@Mixin(value = $T.class, remap = false) public abstract class $M { @Surround(method = \"run\") protected abstract void invalid$enter(int a); }"),
+        new Case("AbstractCatch", "must not be abstract", RUN, "@Mixin(value = $T.class, remap = false) public abstract class $M { " + WHOLE_ENTRY + " @Surround.Catch protected abstract void invalid$caught(Throwable t); }"),
+        new Case("MisorderedLocalAfterCarry", "parameter 1 ('y') is out of order; declare operands first, then @Surround.Local, then @Surround.Carry parameters", RUN, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a) {}" + " @Surround.Finally private void invalid$always(@Surround.Carry int x, @Surround.Local int y) {}")),
+        new Case("LocalAndCarry", "parameter 0 ('a') cannot be both @Surround.Local and @Surround.Carry", RUN, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a) {}" + " @Surround.Finally private void invalid$always(@Surround.Local @Surround.Carry int a) {}")),
+        new Case("LocalCaught", "cannot mark its caught Throwable parameter @Surround.Local", RUN, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int a) {}" + " @Surround.Catch private void invalid$caught(@Surround.Local Throwable e) {}")),
+        new Case("HandleWrongReturn", "must return java.lang.String to match what it surrounds, not int", cls("public String run(String s) { return s.trim(); }"), mixin("@Surround(method = \"run\", at = @At(value = \"INVOKE\", target = \"Ljava/lang/String;trim()Ljava/lang/String;\")) private void invalid$enter(String s) {}" + " @Surround.Catch(handle = true) private int invalid$caught(Throwable e, String s) { return 0; }")),
+        new Case("HandleWithoutAt", "declares handle = true, which only applies when @Surround.at selects a call", RUN, mixin(WHOLE_ENTRY + " @Surround.Catch(handle = true) private void invalid$caught(Throwable e) {}")),
+        new Case("SliceWithoutAt", "declares @Surround.slice, which only applies when @Surround.at selects a call", RUN, mixin("@Surround(method = \"run\", slice = @Slice(from = @At(\"HEAD\"))) private void invalid$enter(int a) {}")),
+        new Case("EntryOperandMismatch", "parameter 0 ('notAnInt') is java.lang.String, which does not match the int operand of call java/lang/Math.abs(I)I", RUN, mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(String notAnInt) {}")),
+        new Case("OrphanWithoutSurround", "@Surround exit handler 'invalid$always' refers to the default id but no @Surround in this mixin declares it; this mixin has no @Surround at all", RUN, mixin(WHOLE_ENTRY), mixin("@Surround.Finally private void invalid$always() {}"))
+    };
+
+    static final Case SUGAR = new Case("Sugar", "@Surround invalid$enter one of its parameters is annotated @Local, @Share or @Cancellable, which a @Surround handler cannot resolve", cls("public int run(int a) { int local = a + 1; return Math.abs(local); }"), mixin("@Surround(method = \"run\", " + ABS + ") private void invalid$enter(int local, @Local(ordinal = 0) int a) {}"));
+
+    static final Case REQUIRE_ZERO_MISS = new Case("RequireZeroMiss", "", RUN, mixin("@Surround(method = \"run\", require = 0, at = @At(value = \"INVOKE\", target = \"Ljava/lang/Math;max(II)I\")) private void invalid$enter(int a, int b) {}" + FINALLY));
+
+    static String compileConfig(boolean mixinExtras) {
+        final List<Case> cases = new ArrayList<>();
+        if (mixinExtras) {
+            cases.add(SUGAR);
+        } else {
+            cases.addAll(Arrays.asList(CASES));
+            cases.add(REQUIRE_ZERO_MISS);
+        }
+        final List<Unit> units = new ArrayList<>();
+        final List<String> mixins = new ArrayList<>();
+        for (Case c : cases) {
+            units.add(new Unit(PACKAGE + "." + c.name, "package " + PACKAGE + "; " + c.target.replace("$T", c.name)));
+            for (int i = 0; i < c.mixins.length; i++) {
+                final String name = c.name + "Mixin" + (i + 1);
+                mixins.add('"' + name + '"');
+                units.add(new Unit(PACKAGE + ".mixin." + name, "package " + PACKAGE + ".mixin; import " + PACKAGE + ".*;" + " import com.gtnewhorizons.angelica.experimental.surround.Surround;" + " import com.llamalad7.mixinextras.sugar.Cancellable;" + " import com.llamalad7.mixinextras.sugar.Local;" + " import org.spongepowered.asm.mixin.Mixin;" + " import org.spongepowered.asm.mixin.injection.At;" + " import org.spongepowered.asm.mixin.injection.Slice;" + c.mixins[i].replace("$T", c.name).replace("$M", name)));
+            }
+        }
+        try {
+            final Path dir = Paths.get("rejection-classes").toAbsolutePath();
+            if (Files.exists(dir)) {
+                try (Stream<Path> stale = Files.walk(dir)) {
+                    stale.sorted(Comparator.reverseOrder()).forEach(path -> path.toFile().delete());
+                }
+            }
+            final Path sources = Files.createDirectories(dir.resolve("src"));
+            final List<String> command = new ArrayList<>(Arrays.asList(System.getProperty("surround.javac"), "-classpath", System.getProperty("java.class.path"), "-d", dir.toString(), "-proc:none", "-g", "--release", "8", "-Xlint:-options"));
+            for (Unit unit : units) {
+                final Path file = sources.resolve(unit.className().replace('.', '/') + ".java");
+                Files.createDirectories(file.getParent());
+                Files.write(file, unit.source().getBytes(StandardCharsets.UTF_8));
+                command.add(file.toString());
+            }
+            final Process javac = new ProcessBuilder(command).redirectErrorStream(true).start();
+            final String output = new String(javac.getInputStream().readAllBytes(), StandardCharsets.UTF_8);
+            if (javac.waitFor() != 0) {
+                throw new IllegalStateException(output);
+            }
+            Files.write(dir.resolve(CONFIG), ("{\"required\": true, \"minVersion\": \"0.8\", \"package\": \"" + PACKAGE + ".mixin\"," + " \"compatibilityLevel\": \"JAVA_8\", \"mixins\": " + mixins + "}").getBytes(StandardCharsets.UTF_8));
+            Launch.classLoader.addURL(dir.toUri().toURL());
+        } catch (IOException | InterruptedException e) {
+            throw new IllegalStateException(e);
+        }
+        return CONFIG;
+    }
+
+    private static String cls(String members) {
+        return "public class $T { " + members + " }";
+    }
+
+    private static String mixin(String members) {
+        return "@Mixin(value = $T.class, remap = false) public class $M { " + members + " }";
+    }
+
+    private record Unit(String className, String source) {
+    }
+
+    static final class Case {
+
+        final String name;
+        final String expected;
+        final String target;
+        final String[] mixins;
+
+        Case(String name, String expected, String target, String... mixins) {
+            this.name = name;
+            this.expected = expected;
+            this.target = target;
+            this.mixins = mixins;
+        }
+
+        void assertRejected() {
+            final String messages = causeChain(transformExpectingFailure(PACKAGE + "." + this.name));
+            assertTrue(messages.contains(this.expected), messages);
+        }
+
+        private static Throwable transformExpectingFailure(String binaryName) {
+            try {
+                MixinTestBootstrap.transformer().transformClassBytes(binaryName, binaryName, MixinTestBootstrap.read(binaryName));
+            } catch (Throwable t) {
+                return t;
+            }
+            throw new AssertionError(binaryName + " transformed without the expected failure");
+        }
+
+        private static String causeChain(Throwable thrown) {
+            final StringBuilder all = new StringBuilder();
+            for (Throwable t = thrown; t != null; t = t.getCause()) {
+                all.append(t).append('\n');
+            }
+            return all.toString();
+        }
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/RejectionTest.java

@@ -0,0 +1,36 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.junit.jupiter.api.Named;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.Arrays;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+class RejectionTest {
+
+    static Stream<Named<RejectionCases.Case>> rejections() {
+        return Arrays.stream(RejectionCases.CASES).map(c -> Named.of(c.name, c));
+    }
+
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("rejections")
+    void anInvalidMixinIsRejectedAtLoad(RejectionCases.Case rejection) {
+        rejection.assertRejected();
+    }
+
+    @Test
+    void aRequireZeroCallSurroundThatMatchesNoCallIsNotRejected() {
+        assertDoesNotThrow(() -> MixinTestBootstrap.transform(RejectionCases.PACKAGE + "." + RejectionCases.REQUIRE_ZERO_MISS.name));
+    }
+
+    @Test
+    @Tag("mixinextras")
+    void mixinExtrasSugarOnACallSiteEntryHandlerIsRejected() {
+        RejectionCases.SUGAR.assertRejected();
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/ScenarioTest.java

@@ -0,0 +1,75 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
+
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.CALL;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.VOID;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.WHOLE;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.args;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.of;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.scenario;
+
+class ScenarioTest {
+
+    static Stream<Arguments> scenarios() {
+        return Stream.of(
+            scenario(WHOLE, "a surround encloses the body and every other injector", "compute", of(7), of(14), "enter 7 1", "head 7", "body 7", "tail 14", "exit 1"),
+            scenario(WHOLE, "the narrowest catch handler wins and finally runs when the body throws", "boom", of(args()), of(IllegalStateException.class), "enterBoom 1", "boomHead", "boom", "caught 1 boom", "exitBoom 1"),
+            scenario(WHOLE, "an instance monitor covers the handlers and the body", "lockedInstance", of(7), of(14), "enterInstance true", "body true", "exitInstance true"),
+            scenario(WHOLE, "a unique exit handler renamed on collision still binds", "run", of(args()), of(VOID), "enter", "run", "target exit", "handler exit"),
+            scenario(WHOLE, "a lower priority mixin is the inner surround", "priority", of(5), of(60), "enterHigh", "enterLow", "body 5", "returnLow 5", "exitLow", "returnHigh 6", "exitHigh"),
+            scenario(WHOLE, "static wide arguments", "wideBody", of(args(2.5d, 5L)), of(7.5d), "enter 1", "body", "exit 1"),
+            scenario(WHOLE, "a throwing entry handler skips the body and the exit handler", "throwingEntry", of(5), of(IllegalArgumentException.class), "enterThrows 5"),
+            scenario(WHOLE, "a throwing finally replaces the return value", "throwingFinally", of(args(9, 4)), of(UnsupportedOperationException.class), "enter 1", "gt", "exitThrows 1"),
+            scenario(WHOLE, "pre-existing exception handlers still fire", "caught", of(4, -4), of(4, -1), "enter 1", "inner-finally", "exit 1", "enter 2", "caught neg", "inner-finally", "exit 2"),
+            scenario(WHOLE, "three kinds bind by kind, not position", "carryThree", of(7), of(14), "enter 8 107 L7", "body 7", "exit 8 107 L7"),
+            scenario(WHOLE, "frame naming an unbuilt object", "carryUninitialized", of(5), of(10), "enter pos", "body 5", "exit pos"),
+            scenario(WHOLE, "entry handler's own try-catch", "carryGuarded", of(-3), of(-6), "recovered", "enter -1", "body -3", "exit -1"),
+            scenario(WHOLE, "assigned in both branches at the end", "carrySplitAtEnd", of(-3), of(-6), "body -3", "exit 2"),
+            scenario(WHOLE, "wide carry ahead of an int across a frame", "carryWideBeforeFrame", of(3), of(6), "positive", "body 3", "exit 3 4"),
+            scenario(WHOLE, "array locals", "carryArrays", of(3), of(6), "body 3", "exit n3 3"),
+            scenario(WHOLE, "widths and an uncarried local between carried ones survive the handler frame", "throwWide", of(3), of(IllegalStateException.class), "enter 4 1.5 3 s3", "body 3", "caught 4 1.5 3", "exit 4 1.5 3"),
+            scenario(WHOLE, "a reference carry is cast to each exit handler's type and a throwing catch handler still runs finally", "throwObject", of(3), of(UnsupportedOperationException.class), "enter o3", "body 3", "caught 2 o3", "exit 2 o3"),
+            scenario(WHOLE, "a reused slot carries the local's value", "reused", of(3), of(6), "tmp 8", "enter 10", "body 3", "exit 10"),
+            scenario(CALL, "a static target takes static handlers around a static callee", "staticTarget", of(4), of(8), "enterStaticTarget 4", "twiceStatic 4", "exitStaticTarget 4 8"),
+            scenario(CALL, "an interface callee is typed as the interface or a supertype", "interfaceCall", of(3), of(4), "enterInterface 3 true", "apply 3", "exitInterface true"),
+            scenario(CALL, "a private callee's receiver is the target itself", "privateCall", of(3), of(4), "enterPrivate true 3", "priv 3", "exitPrivate true 3"),
+            scenario(CALL, "every match is surrounded separately", "all", of(2), of(18), "enterAll 2 1", "twice 2", "exitAll 2 1", "enterAll 3 2", "twice 3", "exitAll 3 2", "enterAll 4 3", "twice 4", "exitAll 4 3"),
+            scenario(CALL, "a slice restricts the matches", "sliced", of(2), of(10), "twice 2", "marker", "enterSliced 3", "twice 3", "exitSliced 3"),
+            scenario(CALL, "a throwing entry handler runs no exit handler and skips the call", "throwingEntry", of(args()), of(IllegalArgumentException.class), "enterThrowingEntry 1"),
+            scenario(CALL, "inject before, modify arg and inject after stay outside", "composed", of(5), of(210), "before 5", "modifyArg 5", "enterComposed 105", "twice 105", "exitComposed 105", "after 5"),
+            scenario(WHOLE, "a void target skips without a skipped handler", "skippedVoid", of(-1, 1), of(VOID, VOID), "enterSkippedVoid -1", "exitSkippedVoid", "enterSkippedVoid 1", "skippedVoid 1", "exitSkippedVoid"),
+            scenario(WHOLE, "an entry handler may call the target directly and then skip", "reentrant", of(1), of(24), "enterReentrant 11 false", "reentrant 11", "exitReentrant 11", "enterReentrant 1 true", "exitReentrant 1"),
+            scenario(WHOLE, "return does not run after a skip and a reference skipped value is returned", "skipAndReturn", of("", "a", "x"), of(null, "a!?", IllegalStateException.class), "enterSkipAndReturn ", "skippedSkipAndReturn", "exitSkipAndReturn ", "enterSkipAndReturn a", "skipAndReturn a", "returnSkipAndReturn a!", "exitSkipAndReturn a", "enterSkipAndReturn x", "skipAndReturn x", "returnSkipAndReturn x!", "exitSkipAndReturn x"),
+            scenario(WHOLE, "an entry handler may catch and rethrow around a direct call", "entryCatches", of(3, -1), of(6, IllegalStateException.class), "entryCatches 3", "exitEntryCatches false", "enterEntryCatches 3", "entryCatches 3", "exitEntryCatches true", "entryCatches -1", "exitEntryCatches false", "entryRethrow negative -1"),
+            scenario(CALL, "a local is selected by name between operands and carries", "byName", of(3), of(49), "enterByName 23 1", "twice 13", "exitByName 13 23 1"),
+            scenario(CALL, "wide locals bind", "wideLocals", of(3), of(31L), "enterWideLocals 30 1.5", "wide 30 1.5", "exitWideLocals 1.5 30"),
+            scenario(CALL, "a handling catch replaces the result over the values below", "valueBelow", of(-3, 4), of(67, 84), "enterValueBelow -3 1", "explode -3", "handleValueBelow -3 1", "exitValueBelow -3 1", "enterValueBelow 4 2", "explode 4", "exitValueBelow 4 2"),
+            scenario(CALL, "a skipped handler supplies the value of a skipped call", "valueSkip", of(-3, 3), of(-300, 6), "enterValueSkip -3 1", "skippedValueSkip -3 1", "exitValueSkip 1", "enterValueSkip 3 2", "twice 3", "exitValueSkip 2"),
+            scenario(CALL, "a void return handler observes and does not run after a handled exception", "observed", of(2, -1), of(VOID, VOID), "enterObserved 2", "maybeBoom 2", "observe 2", "exitObserved 2", "enterObserved -1", "maybeBoom -1", "handleObserved -1", "exitObserved -1"),
+            scenario(CALL, "a handled value bypasses the return handler", "returnAndHandle", of(4, -1), of(80, 7), "enterReturnAndHandle 4", "explode 4", "returnReturnAndHandle 8", "exitReturnAndHandle", "enterReturnAndHandle -1", "explode -1", "handleReturnAndHandle", "exitReturnAndHandle"),
+            scenario(CALL, "the skip path is covered by catch and finally but not by return", "skipFinallyCatch", of(2, -3, 0), of(1004, 3, IllegalStateException.class), "enterSfc 2", "explode 2", "returnSfc 4", "exitSfc 2", "enterSfc -3", "skippedSfc -3", "exitSfc -3", "enterSfc 0", "skippedSfc 0", "caughtSfc zero", "exitSfc 0"),
+            scenario(CALL, "an outer skip runs no inner handler and return handlers chain inner to outer", "nestedSkip", of(-2, 2), of(-1, 50), "enterNestedOuter -2", "skippedNestedOuter", "exitNestedOuter -2", "enterNestedOuter 2", "enterNestedInner 2", "twice 2", "returnNestedInner 4", "exitNestedInner 2", "returnNestedOuter 5", "exitNestedOuter 2"),
+            scenario(CALL, "a skip skips the redirect handler inside", "redirectedSkip", of(-1, 3), of(0, 7), "enterRedirectedSkip -1", "exitRedirectedSkip -1", "enterRedirectedSkip 3", "redirectSkip 3", "twice 3", "exitRedirectedSkip 3"),
+            scenario(CALL, "a final skip derived from a carry computed by a unique helper binds", "helperSkip", of(-4, 4), of(-1, 8), "part -4", "enterHelper -1", "skippedHelper", "exitHelper -1", "part 4", "enterHelper 4", "twice 4", "exitHelper 4"),
+            scenario(CALL, "wide operands skip and return with an int skip flag", "wideSkip", of(args(-2L, 3.0d), args(5L, 2.5d)), of(-19L, 108L), "enterWideSkip -2 3.0", "skippedWideSkip -2 1.5", "exitWideSkip -2 3.0", "enterWideSkip 5 2.5", "wide 5 2.5", "returnWideSkip 7 1.25", "exitWideSkip 5 2.5"),
+            scenario(CALL, "an entry-only call surround needs no exit handler even with a skip", "entryOnlySkip", of(1, -1), of(1, -1), "enterOnlySkip 1", "enterOnlySkip -1", "render -1"),
+            scenario(CALL, "an entry-only whole-method surround", "entryOnlyWhole", of(args()), of(VOID), "enterOnlyWhole", "entryOnlyWhole"),
+            scenario(CALL, "a skip restores the values below the call when the entry catches", "skipBelowRestored", of(-2, 3, 200), of(980, 1006, 1400), "enterSkipBelowRestored -2", "skippedSkipBelowRestored -2", "exitSkipBelowRestored -2", "enterSkipBelowRestored 3", "twice 3", "exitSkipBelowRestored 3", "entryCaughtSkipBelowRestored 200", "twice 200", "exitSkipBelowRestored 200"),
+            scenario(CALL, "an inner skip completes normally for an outer return handler", "innerSkipOuterReturn", of(-2, 3), of(-199, 7), "enterOuterReturn -2", "enterInnerSkip -2", "skippedInnerSkip -2", "exitInnerSkip -2", "returnOuterReturn -200", "exitOuterReturn -2", "enterOuterReturn 3", "enterInnerSkip 3", "twice 3", "exitInnerSkip 3", "returnOuterReturn 6", "exitOuterReturn 3"),
+            scenario(CALL, "a call inside a constructor call's arguments can be skipped", "skipInsideNew", of(-2, 3), of(-20, 6), "enterSkipInsideNew -2", "skippedSkipInsideNew -2", "exitSkipInsideNew -2", "enterSkipInsideNew 3", "twice 3", "exitSkipInsideNew 3"),
+            scenario(CALL, "a call surround skips inside a body moved by a whole-method surround", "movedBody", of(-2, 3), of(990, 1008), "enterMovedWhole -2", "enterMovedCall -1 -2", "skippedMovedCall -1 -2", "exitMovedCall -1 -2", "exitMovedWhole -2", "enterMovedWhole 3", "enterMovedCall 4 3", "twice 4", "exitMovedCall 4 3", "exitMovedWhole 3"),
+            scenario(WHOLE, "a branching entry handler around the whole method", "branching", of(-3), of(-6), "enterBranching negative", "body -3", "exitBranching negative")
+        );
+    }
+
+    @ParameterizedTest(name = "{0}")
+    @MethodSource("scenarios")
+    void scenarios(String method, String target, Object[] inputs, Object[] outputs, String[] events) throws Exception {
+        MixinTestBootstrap.assertScenario(target, method, inputs, outputs, events);
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/WholeMethodTest.java

@@ -0,0 +1,99 @@
+package com.gtnewhorizons.angelica.experimental.surround;
+
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import net.minecraft.launchwrapper.Launch;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
+import org.spongepowered.asm.lib.tree.AbstractInsnNode;
+import org.spongepowered.asm.lib.tree.ClassNode;
+import org.spongepowered.asm.lib.tree.LabelNode;
+import org.spongepowered.asm.lib.tree.LineNumberNode;
+import org.spongepowered.asm.lib.tree.LocalVariableNode;
+import org.spongepowered.asm.lib.tree.MethodNode;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.WHOLE;
+import static com.gtnewhorizons.angelica.experimental.surround.MixinTestBootstrap.call;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class WholeMethodTest {
+
+    @BeforeEach
+    void resetTrace() {
+        Trace.reset();
+    }
+
+    @Test
+    void oneEntryHandlerCanSurroundSeveralTargets() throws Exception {
+        call(WHOLE, "alpha");
+        call(WHOLE, "beta");
+        Trace.assertEvents("enterBoth 1", "alpha", "exitBoth 1", "enterBoth 2", "beta", "exitBoth 2");
+    }
+
+    @Test
+    void theWrapperKeepsTheEntryHandlersLinesAndTheBodyKeepsItsOwn() {
+        final ClassNode merged = MixinTestBootstrap.transformedNode(WHOLE);
+        final List<Integer> entryLines = lines(bySuffix(merged, "$surround$enterBranching"));
+        assertFalse(entryLines.isEmpty(), "fixture compiled without line numbers");
+        assertEquals(entryLines, lines(MixinTestBootstrap.method(merged, "branching")));
+        assertEquals(lines(MixinTestBootstrap.method(MixinTestBootstrap.originalNode(WHOLE), "branching")), lines(MixinTestBootstrap.method(merged, "branching$surround")));
+    }
+
+    @Test
+    void aReusedSlotNamesTheCarriedLocal() {
+        final MethodNode wrapper = MixinTestBootstrap.method(MixinTestBootstrap.transformedNode(WHOLE), "reused");
+        LabelNode last = null;
+        for (AbstractInsnNode insn = wrapper.instructions.getLast(); last == null; insn = insn.getPrevious()) {
+            last = insn instanceof LabelNode label ? label : null;
+        }
+        final List<String> toEnd = new ArrayList<>();
+        for (LocalVariableNode local : wrapper.localVariables) {
+            if (local.end == last) {
+                toEnd.add(local.name);
+            }
+        }
+        assertTrue(toEnd.contains("prev") && !toEnd.contains("tmp"), "locals live to the end: " + toEnd);
+    }
+
+    @Test
+    void theWrapperMatchesTheGoldens() {
+        MixinTestBootstrap.assertGolden(WHOLE, "skipAndReturn", "whole-skip-return");
+    }
+
+    @Test
+    @EnabledIfSystemProperty(named = "surround.test.obf", matches = "true")
+    void theLaunchClassLoaderTransformersSeeTheMixinClass() throws Exception {
+        MixinTestBootstrap.transform(WHOLE);
+        final Set<?> seen = (Set<?>) Launch.classLoader.loadClass(LocalSortingTransformer.class.getName()).getField("SEEN").get(null);
+        assertTrue(seen.contains("com.gtnewhorizons.angelica.experimental.surround.integration.mixin.MixinWholeTarget"), seen.toString());
+    }
+
+    private static MethodNode bySuffix(ClassNode node, String suffix) {
+        for (MethodNode method : node.methods) {
+            if (method.name.endsWith(suffix)) {
+                return method;
+            }
+        }
+        final List<String> names = new ArrayList<>();
+        for (MethodNode method : node.methods) {
+            names.add(method.name);
+        }
+        throw new AssertionError("no method ending " + suffix + " in " + names);
+    }
+
+    private static List<Integer> lines(MethodNode method) {
+        final List<Integer> lines = new ArrayList<>();
+        for (AbstractInsnNode insn : method.instructions.toArray()) {
+            if (insn instanceof LineNumberNode ln) {
+                lines.add(ln.line);
+            }
+        }
+        return lines;
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.java

@@ -0,0 +1,230 @@
+package com.gtnewhorizons.angelica.experimental.surround.integration;
+
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.IntUnaryOperator;
+
+public class CallTarget {
+
+    public static final String CALLEE = "Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;";
+    public static final String TWICE = CALLEE + "twice(I)I";
+
+    private final Callee callee = new Callee();
+    private final IntUnaryOperator op = new Callee();
+    private final Render renderer = new Render();
+
+    public static int staticTarget(int a) {
+        return Callee.twiceStatic(a);
+    }
+
+    public int interfaceCall(int a) {
+        return this.op.applyAsInt(a);
+    }
+
+    public int privateCall(int a) {
+        return this.priv(a);
+    }
+
+    private int priv(int a) {
+        Trace.add("priv " + a);
+        return a + 1;
+    }
+
+    public int all(int a) {
+        return this.callee.twice(a) + this.callee.twice(a + 1) + this.callee.twice(a + 2);
+    }
+
+    public int sliced(int a) {
+        final int first = this.callee.twice(a);
+        Callee.marker();
+        return first + this.callee.twice(a + 1);
+    }
+
+    public void throwingEntry() {
+        this.callee.twice(1);
+    }
+
+    public int composed(int a) {
+        return this.callee.twice(a);
+    }
+
+    public boolean render(Entity entity, double x, double y, double z, float yaw, float partial, boolean flag) {
+        Render render = null;
+        try {
+            render = this.renderer;
+            if (render != null && entity != null) {
+                try {
+                    render.doRender(entity, x, y, z, yaw, partial);
+                } catch (Throwable throwable1) {
+                    throw new ReportedException("Rendering entity in world", throwable1);
+                }
+                try {
+                    render.doRenderShadowAndFire(entity, x, y, z, yaw, partial);
+                } catch (Throwable throwable2) {
+                    throw new ReportedException("Post-rendering entity in world", throwable2);
+                }
+                if (flag) {
+                    Trace.add("boundingBox " + entity.name);
+                }
+            }
+            return true;
+        } catch (Throwable throwable) {
+            throw new ReportedException("Rendering entity (outer)", throwable);
+        }
+    }
+
+    public int byName(int a) {
+        final int first = a + 10;
+        final int second = a + 20;
+        return this.callee.twice(first) + second;
+    }
+
+    public long wideLocals(int a) {
+        final long big = a * 10L;
+        final double half = a / 2.0;
+        return this.callee.wide(big, half);
+    }
+
+    public int valueBelow(int a) {
+        return a + this.callee.explode(a) * 10;
+    }
+
+    public int valueSkip(int a) {
+        return this.callee.twice(a);
+    }
+
+    public void observed(int a) {
+        this.callee.maybeBoom(a);
+    }
+
+    public int returnAndHandle(int a) {
+        return this.callee.explode(a);
+    }
+
+    public int skipFinallyCatch(int a) {
+        return this.callee.explode(a);
+    }
+
+    public int nestedSkip(int a) {
+        return this.callee.twice(a);
+    }
+
+    public int redirectedSkip(int a) {
+        return this.callee.twice(a);
+    }
+
+    public int helperSkip(int a) {
+        return this.callee.twice(a);
+    }
+
+    public long wideSkip(long a, double b) {
+        return this.callee.wide(a, b) + 1L;
+    }
+
+    public int entryOnlySkip(int a) {
+        this.callee.render(a);
+        return a;
+    }
+
+    public void entryOnlyWhole() {
+        Trace.add("entryOnlyWhole");
+    }
+
+    public int skipBelowRestored(int a) {
+        return 1000 + this.callee.twice(a);
+    }
+
+    public int innerSkipOuterReturn(int a) {
+        return this.callee.twice(a);
+    }
+
+    public int skipInsideNew(int a) {
+        return new AtomicInteger(this.callee.twice(a)).get();
+    }
+
+    public int movedBody(int a) {
+        final int b = a + 1;
+        return 1000 + this.callee.twice(b);
+    }
+
+    public static class Callee implements IntUnaryOperator {
+
+        public int twice(int a) {
+            Trace.add("twice " + a);
+            return a * 2;
+        }
+
+        public static int twiceStatic(int a) {
+            Trace.add("twiceStatic " + a);
+            return a * 2;
+        }
+
+        public static void marker() {
+            Trace.add("marker");
+        }
+
+        public long wide(long a, double b) {
+            Trace.add("wide " + a + " " + b);
+            return a + (long) b;
+        }
+
+        @Override
+        public int applyAsInt(int a) {
+            Trace.add("apply " + a);
+            return a + 1;
+        }
+
+        public int explode(int a) {
+            Trace.add("explode " + a);
+            if (a < 0) {
+                throw new IllegalStateException("negative " + a);
+            }
+            return a * 2;
+        }
+
+        public void maybeBoom(int a) {
+            Trace.add("maybeBoom " + a);
+            if (a < 0) {
+                throw new IllegalStateException("boom " + a);
+            }
+        }
+
+        public void render(int a) {
+            Trace.add("render " + a);
+        }
+    }
+
+    public static class Entity {
+
+        public final String name;
+        public boolean explode;
+
+        public Entity(String name) {
+            this.name = name;
+        }
+    }
+
+    public static class Render {
+
+        public void doRender(Entity entity, double x, double y, double z, float yaw, float partial) {
+            Trace.add("doRender " + entity.name + " " + x + " " + partial);
+            if (entity.explode) {
+                throw new RuntimeException("gpu");
+            }
+        }
+
+        public void doRenderShadowAndFire(Entity entity, double x, double y, double z, float yaw, float partial) {
+            Trace.add("shadow " + entity.name);
+        }
+    }
+
+    public static class ReportedException extends RuntimeException {
+
+        private static final long serialVersionUID = 1L;
+
+        public ReportedException(String description, Throwable cause) {
+            super(description, cause);
+        }
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.java

@@ -0,0 +1,169 @@
+package com.gtnewhorizons.angelica.experimental.surround.integration;
+
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+
+public class WholeTarget {
+
+    public static boolean guard;
+
+    public int compute(int a) {
+        Trace.add("body " + a);
+        return a * 2;
+    }
+
+    public void boom() {
+        Trace.add("boom");
+        throw new IllegalStateException("boom");
+    }
+
+    public void alpha() {
+        Trace.add("alpha");
+    }
+
+    public void beta() {
+        Trace.add("beta");
+    }
+
+    public synchronized int lockedInstance(int a) {
+        Trace.add("body " + Thread.holdsLock(this));
+        return a * 2;
+    }
+
+    public void run() {
+        Trace.add("run");
+        exit();
+    }
+
+    private void exit() {
+        Trace.add("target exit");
+    }
+
+    public int priority(int a) {
+        Trace.add("body " + a);
+        return a;
+    }
+
+    public int branching(int a) {
+        Trace.add("body " + a);
+        return a * 2;
+    }
+
+    public void skippedVoid(int a) {
+        Trace.add("skippedVoid " + a);
+    }
+
+    public int reentrant(int a) {
+        Trace.add("reentrant " + a);
+        return a + 1;
+    }
+
+    public String skipAndReturn(String a) {
+        Trace.add("skipAndReturn " + a);
+        return a + "!";
+    }
+
+    public static int entryCatches(int a) {
+        Trace.add("entryCatches " + a);
+        if (a < 0) {
+            throw new IllegalStateException("negative " + a);
+        }
+        return a * 2;
+    }
+
+    public int throwingFinally(int a, int b) {
+        return pick(a, b);
+    }
+
+    private static int pick(int a, int b) {
+        if (a > b) {
+            Trace.add("gt");
+            return a;
+        }
+        if (a < b) {
+            Trace.add("lt");
+            return b;
+        }
+        Trace.add("eq");
+        return 0;
+    }
+
+    public static double wideBody(double a, long b) {
+        Trace.add("body");
+        return a + b;
+    }
+
+    public void throwWide(int a) {
+        thrown(a);
+    }
+
+    public void throwObject(int a) {
+        thrown(a);
+    }
+
+    private static void thrown(int a) {
+        Trace.add("body " + a);
+        throw new IllegalStateException("boom " + a);
+    }
+
+    public void throwingEntry(int a) {
+        Trace.add("body " + a);
+    }
+
+    public int caught(int a) {
+        try {
+            if (a < 0) {
+                throw new IllegalArgumentException("neg");
+            }
+            return a;
+        } catch (IllegalArgumentException e) {
+            Trace.add("caught " + e.getMessage());
+            return -1;
+        } finally {
+            Trace.add("inner-finally");
+        }
+    }
+
+    public int carryThree(int a) {
+        return carried(a);
+    }
+
+    public int carryUninitialized(int a) {
+        return carried(a);
+    }
+
+    public int carryGuarded(int a) {
+        return carried(a);
+    }
+
+    public int carrySplitAtEnd(int a) {
+        return carried(a);
+    }
+
+    public int carryWideBeforeFrame(int a) {
+        return carried(a);
+    }
+
+    public int carryArrays(int a) {
+        return carried(a);
+    }
+
+    public int reused(int a) {
+        return carried(a);
+    }
+
+    private static int carried(int a) {
+        Trace.add("body " + a);
+        return a * 2;
+    }
+
+    public static int risky(int a) {
+        if (a < 0) {
+            throw new IllegalArgumentException("neg");
+        }
+        return a * 3;
+    }
+
+    public static Object asObject(Object value) {
+        return value;
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/integration/WrapTarget.java

@@ -0,0 +1,24 @@
+package com.gtnewhorizons.angelica.experimental.surround.integration;
+
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.Callee;
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+
+public class WrapTarget {
+
+    private final Callee callee = new Callee();
+
+    public int wrapped(int a) {
+        Trace.add("body " + a);
+        return a * 2;
+    }
+
+    public int originalOperands(int a) {
+        return this.callee.twice(a);
+    }
+
+    public int shifted(int a) {
+        final int local = a + 1;
+        final String label = "L" + local;
+        return this.callee.twice(local) + label.length();
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/integration/mixin/MixinCallTarget.java

@@ -0,0 +1,504 @@
+package com.gtnewhorizons.angelica.experimental.surround.integration.mixin;
+
+import com.gtnewhorizons.angelica.experimental.surround.Surround;
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget;
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.Callee;
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.Entity;
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.Render;
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyArg;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.Slice;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.util.function.IntUnaryOperator;
+
+import static com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.CALLEE;
+import static com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.TWICE;
+
+@Mixin(value = CallTarget.class, remap = false)
+public class MixinCallTarget {
+
+    private static final String WIDE = CALLEE + "wide(JD)J";
+    private static final String EXPLODE = CALLEE + "explode(I)I";
+    private static final String MAYBE_BOOM = CALLEE + "maybeBoom(I)V";
+    private static final String DO_RENDER = "Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Render;" + "doRender(Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Entity;DDDFF)V";
+    private static final long QUEUED = -1L;
+
+    @Surround(method = "staticTarget", at = @At(value = "INVOKE", target = CALLEE + "twiceStatic(I)I"), id = "staticTarget")
+    private static void surround$enterStaticTarget(int a) {
+        @Surround.Carry int doubled = a * 2;
+        Trace.add("enterStaticTarget " + a);
+    }
+
+    @Surround.Finally("staticTarget")
+    private static void surround$exitStaticTarget(int a, @Surround.Carry int doubled) {
+        Trace.add("exitStaticTarget " + a + " " + doubled);
+    }
+
+    @Surround(method = "interfaceCall", at = @At(value = "INVOKE", target = "Ljava/util/function/IntUnaryOperator;applyAsInt(I)I"), id = "interface")
+    private void surround$enterInterface(IntUnaryOperator op, int a) {
+        Trace.add("enterInterface " + a + " " + (op instanceof Callee));
+    }
+
+    @Surround.Finally("interface")
+    private void surround$exitInterface(Object op) {
+        Trace.add("exitInterface " + (op instanceof Callee));
+    }
+
+    @Surround(method = "privateCall", at = @At(value = "INVOKE", target = "Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget;priv(I)I"), id = "private")
+    private void surround$enterPrivate(CallTarget self, int a) {
+        Trace.add("enterPrivate " + (self == (Object) this) + " " + a);
+    }
+
+    @Surround.Finally("private")
+    private void surround$exitPrivate(CallTarget self, int a) {
+        Trace.add("exitPrivate " + (self == (Object) this) + " " + a);
+    }
+
+    @Surround(method = "all", at = @At(value = "INVOKE", target = TWICE), id = "all", require = 3)
+    private void surround$enterAll(Callee callee, int a) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enterAll " + a + " " + token);
+    }
+
+    @Surround.Finally("all")
+    private void surround$exitAll(Callee callee, int a, @Surround.Carry long token) {
+        Trace.add("exitAll " + a + " " + token);
+    }
+
+    @Surround(method = "sliced", at = @At(value = "INVOKE", target = TWICE), slice = @Slice(from = @At(value = "INVOKE", target = CALLEE + "marker()V")), id = "sliced", require = 1, allow = 1)
+    private void surround$enterSliced(Callee callee, int a) {
+        Trace.add("enterSliced " + a);
+    }
+
+    @Surround.Finally("sliced")
+    private void surround$exitSliced(Callee callee, int a) {
+        Trace.add("exitSliced " + a);
+    }
+
+    @Surround(method = "throwingEntry", at = @At(value = "INVOKE", target = TWICE), id = "throwingEntry")
+    private void surround$enterThrowingEntry(Callee callee, int a) {
+        Trace.add("enterThrowingEntry " + a);
+        if (a > 0) {
+            throw new IllegalArgumentException("entry");
+        }
+    }
+
+    @Surround.Catch("throwingEntry")
+    private void surround$caughtThrowingEntry(Throwable error) {
+        Trace.add("caughtThrowingEntry");
+    }
+
+    @Surround.Finally("throwingEntry")
+    private void surround$exitThrowingEntry() {
+        Trace.add("exitThrowingEntry");
+    }
+
+    @Inject(method = "composed", at = @At(value = "INVOKE", target = TWICE))
+    private void surround$before(int a, CallbackInfoReturnable<Integer> cir) {
+        Trace.add("before " + a);
+    }
+
+    @Inject(method = "composed", at = @At(value = "INVOKE", target = TWICE, shift = At.Shift.AFTER))
+    private void surround$after(int a, CallbackInfoReturnable<Integer> cir) {
+        Trace.add("after " + a);
+    }
+
+    @ModifyArg(method = "composed", at = @At(value = "INVOKE", target = TWICE))
+    private int surround$plusHundred(int a) {
+        Trace.add("modifyArg " + a);
+        return a + 100;
+    }
+
+    @Surround(method = "composed", at = @At(value = "INVOKE", target = TWICE), id = "composed")
+    private void surround$enterComposed(Callee callee, int a) {
+        Trace.add("enterComposed " + a);
+    }
+
+    @Surround.Finally("composed")
+    private void surround$exitComposed(Callee callee, int a) {
+        Trace.add("exitComposed " + a);
+    }
+
+    @Redirect(method = "render", at = @At(value = "INVOKE", target = DO_RENDER))
+    private void surround$redirectDoRender(Render render, Entity entity, double x, double y, double z, float yaw, float partial) {
+        Trace.add("redirect " + entity.name);
+        render.doRender(entity, x, y, z, yaw, partial);
+    }
+
+    @Surround(method = "render", at = @At(value = "INVOKE", target = DO_RENDER), id = "render", require = 1)
+    private void surround$enterDoRender(Render render, Entity entity, double x, double y, double z, float yaw, float partial) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enterDoRender " + entity.name + " " + token);
+    }
+
+    @Surround.Catch("render")
+    private void surround$caughtDoRender(Throwable error, Render render, Entity entity, @Surround.Carry long token) {
+        Trace.add("caughtDoRender " + entity.name + " " + error.getMessage() + " " + token);
+    }
+
+    @Surround.Finally("render")
+    private void surround$exitDoRender(Render render, Entity entity, @Surround.Carry long token) {
+        Trace.add("exitDoRender " + entity.name + " " + token);
+    }
+
+    @Surround(method = "byName", at = @At(value = "INVOKE", target = TWICE), id = "byName")
+    private void surround$enterByName(@Surround.Local(name = "second") int second) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enterByName " + second + " " + token);
+    }
+
+    @Surround.Finally("byName")
+    private void surround$exitByName(Callee callee, int first, @Surround.Local(name = "second") int second, @Surround.Carry long token) {
+        Trace.add("exitByName " + first + " " + second + " " + token);
+    }
+
+    @Surround(method = "wideLocals", at = @At(value = "INVOKE", target = WIDE), id = "wideLocals")
+    private void surround$enterWideLocals(Callee callee, long a, double b, @Surround.Local long big, @Surround.Local double half) {
+        Trace.add("enterWideLocals " + big + " " + half);
+    }
+
+    @Surround.Finally("wideLocals")
+    private void surround$exitWideLocals(@Surround.Local(index = 4) double half, @Surround.Local(index = 2) long big) {
+        Trace.add("exitWideLocals " + half + " " + big);
+    }
+
+    @Surround(method = "valueBelow", at = @At(value = "INVOKE", target = EXPLODE), id = "valueBelow")
+    private void surround$enterValueBelow(Callee callee, int a) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enterValueBelow " + a + " " + token);
+    }
+
+    @Surround.Catch(value = "valueBelow", handle = true)
+    private int surround$handleValueBelow(IllegalStateException error, Callee callee, int a, @Surround.Carry long token) {
+        Trace.add("handleValueBelow " + a + " " + token);
+        return 7;
+    }
+
+    @Surround.Finally("valueBelow")
+    private void surround$exitValueBelow(Callee callee, int a, @Surround.Carry long token) {
+        Trace.add("exitValueBelow " + a + " " + token);
+    }
+
+    @Surround(method = "valueSkip", at = @At(value = "INVOKE", target = TWICE), id = "valueSkip")
+    private void surround$enterValueSkip(Callee callee, int a) {
+        @Surround.Carry long token = Trace.nextToken();
+        @Surround.Skip boolean skip = a < 0;
+        Trace.add("enterValueSkip " + a + " " + token);
+    }
+
+    @Surround.Skipped("valueSkip")
+    private int surround$skippedValueSkip(Callee callee, int a, @Surround.Carry long token) {
+        Trace.add("skippedValueSkip " + a + " " + token);
+        return a * 100;
+    }
+
+    @Surround.Finally("valueSkip")
+    private void surround$exitValueSkip(@Surround.Carry long token) {
+        Trace.add("exitValueSkip " + token);
+    }
+
+    @Surround(method = "observed", at = @At(value = "INVOKE", target = MAYBE_BOOM), id = "observed")
+    private void surround$enterObserved(Callee callee, int a) {
+        Trace.add("enterObserved " + a);
+    }
+
+    @Surround.Return("observed")
+    private void surround$observe(Callee callee, int a) {
+        Trace.add("observe " + a);
+    }
+
+    @Surround.Catch(value = "observed", handle = true)
+    private void surround$handleObserved(IllegalStateException error, Callee callee, int a) {
+        Trace.add("handleObserved " + a);
+    }
+
+    @Surround.Finally("observed")
+    private void surround$exitObserved(Callee callee, int a) {
+        Trace.add("exitObserved " + a);
+    }
+
+    @Surround(method = "returnAndHandle", at = @At(value = "INVOKE", target = EXPLODE), id = "returnAndHandle")
+    private void surround$enterReturnAndHandle(Callee callee, int a) {
+        Trace.add("enterReturnAndHandle " + a);
+    }
+
+    @Surround.Return("returnAndHandle")
+    private int surround$returnReturnAndHandle(int result) {
+        Trace.add("returnReturnAndHandle " + result);
+        return result * 10;
+    }
+
+    @Surround.Catch(value = "returnAndHandle", handle = true)
+    private int surround$handleReturnAndHandle(IllegalStateException error) {
+        Trace.add("handleReturnAndHandle");
+        return 7;
+    }
+
+    @Surround.Finally("returnAndHandle")
+    private void surround$exitReturnAndHandle() {
+        Trace.add("exitReturnAndHandle");
+    }
+
+    @Surround(method = "skipFinallyCatch", at = @At(value = "INVOKE", target = EXPLODE), id = "sfc")
+    private void surround$enterSfc(Callee callee, int a) {
+        @Surround.Skip boolean skip = a <= 0;
+        Trace.add("enterSfc " + a);
+    }
+
+    @Surround.Skipped("sfc")
+    private int surround$skippedSfc(Callee callee, int a) {
+        Trace.add("skippedSfc " + a);
+        if (a == 0) {
+            throw new IllegalStateException("zero");
+        }
+        return -a;
+    }
+
+    @Surround.Return("sfc")
+    private int surround$returnSfc(int result, Callee callee, int a) {
+        Trace.add("returnSfc " + result);
+        return result + 1000;
+    }
+
+    @Surround.Catch("sfc")
+    private void surround$caughtSfc(IllegalStateException error, Callee callee, int a) {
+        Trace.add("caughtSfc " + error.getMessage());
+    }
+
+    @Surround.Finally("sfc")
+    private void surround$exitSfc(Callee callee, int a) {
+        Trace.add("exitSfc " + a);
+    }
+
+    @Surround(method = "nestedSkip", at = @At(value = "INVOKE", target = TWICE), id = "nestedInner")
+    private void surround$enterNestedInner(Callee callee, int a) {
+        Trace.add("enterNestedInner " + a);
+    }
+
+    @Surround.Return("nestedInner")
+    private int surround$returnNestedInner(int result) {
+        Trace.add("returnNestedInner " + result);
+        return result + 1;
+    }
+
+    @Surround.Finally("nestedInner")
+    private void surround$exitNestedInner(Callee callee, int a) {
+        Trace.add("exitNestedInner " + a);
+    }
+
+    @Surround(method = "nestedSkip", at = @At(value = "INVOKE", target = TWICE), id = "nestedOuter")
+    private void surround$enterNestedOuter(Callee callee, int a) {
+        @Surround.Skip boolean skip = a < 0;
+        Trace.add("enterNestedOuter " + a);
+    }
+
+    @Surround.Skipped("nestedOuter")
+    private int surround$skippedNestedOuter() {
+        Trace.add("skippedNestedOuter");
+        return -1;
+    }
+
+    @Surround.Return("nestedOuter")
+    private int surround$returnNestedOuter(int result) {
+        Trace.add("returnNestedOuter " + result);
+        return result * 10;
+    }
+
+    @Surround.Finally("nestedOuter")
+    private void surround$exitNestedOuter(Callee callee, int a) {
+        Trace.add("exitNestedOuter " + a);
+    }
+
+    @Redirect(method = "redirectedSkip", at = @At(value = "INVOKE", target = TWICE))
+    private int surround$redirectSkip(Callee callee, int a) {
+        Trace.add("redirectSkip " + a);
+        return callee.twice(a) + 1;
+    }
+
+    @Surround(method = "redirectedSkip", at = @At(value = "INVOKE", target = TWICE), id = "redirectedSkip")
+    private void surround$enterRedirectedSkip(Callee callee, int a) {
+        @Surround.Skip boolean skip = a < 0;
+        Trace.add("enterRedirectedSkip " + a);
+    }
+
+    @Surround.Skipped("redirectedSkip")
+    private int surround$skippedRedirectedSkip(Callee callee, int a) {
+        return 0;
+    }
+
+    @Surround.Finally("redirectedSkip")
+    private void surround$exitRedirectedSkip(Callee callee, int a) {
+        Trace.add("exitRedirectedSkip " + a);
+    }
+
+    @Unique
+    private static long surround$part(int a) {
+        Trace.add("part " + a);
+        return a < 0 ? QUEUED : a;
+    }
+
+    @Surround(method = "helperSkip", at = @At(value = "INVOKE", target = TWICE), id = "helper")
+    private void surround$enterHelper(Callee callee, int a) {
+        @Surround.Carry final long part = surround$part(a);
+        @Surround.Skip final boolean queued = part == QUEUED;
+        Trace.add("enterHelper " + part);
+    }
+
+    @Surround.Skipped("helper")
+    private int surround$skippedHelper(Callee callee, int a, @Surround.Carry long part) {
+        Trace.add("skippedHelper");
+        return (int) part;
+    }
+
+    @Surround.Finally("helper")
+    private void surround$exitHelper(@Surround.Carry long part) {
+        Trace.add("exitHelper " + part);
+    }
+
+    @Surround(method = "wideSkip", at = @At(value = "INVOKE", target = WIDE), id = "wideSkip")
+    private void surround$enterWideSkip(Callee callee, long a, double b) {
+        @Surround.Carry double halved = b / 2;
+        @Surround.Skip int skip = a < 0 ? 1 : 0;
+        Trace.add("enterWideSkip " + a + " " + b);
+    }
+
+    @Surround.Skipped("wideSkip")
+    private long surround$skippedWideSkip(Callee callee, long a, @Surround.Carry double halved) {
+        Trace.add("skippedWideSkip " + a + " " + halved);
+        return a * 10L;
+    }
+
+    @Surround.Return("wideSkip")
+    private long surround$returnWideSkip(long result, Callee callee, long a, double b, @Surround.Carry double halved) {
+        Trace.add("returnWideSkip " + result + " " + halved);
+        return result + 100L;
+    }
+
+    @Surround.Finally("wideSkip")
+    private void surround$exitWideSkip(Callee callee, long a, double b) {
+        Trace.add("exitWideSkip " + a + " " + b);
+    }
+
+    @Surround(method = "entryOnlySkip", at = @At(value = "INVOKE", target = CALLEE + "render(I)V"), id = "entryOnlySkip")
+    private void surround$enterOnlySkip(Callee callee, int a) {
+        @Surround.Skip boolean skip = a > 0;
+        Trace.add("enterOnlySkip " + a);
+    }
+
+    @Surround(method = "entryOnlyWhole", id = "entryOnlyWhole")
+    private void surround$enterOnlyWhole() {
+        Trace.add("enterOnlyWhole");
+    }
+
+    @Surround(method = "skipBelowRestored", at = @At(value = "INVOKE", target = TWICE), id = "skipBelowRestored")
+    private void surround$enterSkipBelowRestored(Callee callee, int a) {
+        @Surround.Skip boolean skip = a < 0;
+        try {
+            if (a > 100) {
+                throw new IllegalArgumentException("big");
+            }
+            Trace.add("enterSkipBelowRestored " + a);
+        } catch (IllegalArgumentException e) {
+            Trace.add("entryCaughtSkipBelowRestored " + a);
+        }
+    }
+
+    @Surround.Skipped("skipBelowRestored")
+    private int surround$skippedSkipBelowRestored(Callee callee, int a) {
+        Trace.add("skippedSkipBelowRestored " + a);
+        return a * 10;
+    }
+
+    @Surround.Finally("skipBelowRestored")
+    private void surround$exitSkipBelowRestored(Callee callee, int a) {
+        Trace.add("exitSkipBelowRestored " + a);
+    }
+
+    @Surround(method = "innerSkipOuterReturn", at = @At(value = "INVOKE", target = TWICE), id = "innerSkip")
+    private void surround$enterInnerSkip(Callee callee, int a) {
+        @Surround.Skip boolean skip = a < 0;
+        Trace.add("enterInnerSkip " + a);
+    }
+
+    @Surround.Skipped("innerSkip")
+    private int surround$skippedInnerSkip(Callee callee, int a) {
+        Trace.add("skippedInnerSkip " + a);
+        return a * 100;
+    }
+
+    @Surround.Finally("innerSkip")
+    private void surround$exitInnerSkip(Callee callee, int a) {
+        Trace.add("exitInnerSkip " + a);
+    }
+
+    @Surround(method = "innerSkipOuterReturn", at = @At(value = "INVOKE", target = TWICE), id = "outerReturn")
+    private void surround$enterOuterReturn(Callee callee, int a) {
+        Trace.add("enterOuterReturn " + a);
+    }
+
+    @Surround.Return("outerReturn")
+    private int surround$returnOuterReturn(int result) {
+        Trace.add("returnOuterReturn " + result);
+        return result + 1;
+    }
+
+    @Surround.Finally("outerReturn")
+    private void surround$exitOuterReturn(Callee callee, int a) {
+        Trace.add("exitOuterReturn " + a);
+    }
+
+    @Surround(method = "skipInsideNew", at = @At(value = "INVOKE", target = TWICE), id = "skipInsideNew")
+    private void surround$enterSkipInsideNew(Callee callee, int a) {
+        @Surround.Skip boolean skip = a < 0;
+        Trace.add("enterSkipInsideNew " + a);
+    }
+
+    @Surround.Skipped("skipInsideNew")
+    private int surround$skippedSkipInsideNew(Callee callee, int a) {
+        Trace.add("skippedSkipInsideNew " + a);
+        return a * 10;
+    }
+
+    @Surround.Catch("skipInsideNew")
+    private void surround$caughtSkipInsideNew(Throwable error) {
+        Trace.add("caughtSkipInsideNew");
+    }
+
+    @Surround.Finally("skipInsideNew")
+    private void surround$exitSkipInsideNew(Callee callee, int a) {
+        Trace.add("exitSkipInsideNew " + a);
+    }
+
+    @Surround(method = "movedBody", id = "movedWhole")
+    private void surround$enterMovedWhole(int a) {
+        Trace.add("enterMovedWhole " + a);
+    }
+
+    @Surround.Finally("movedWhole")
+    private void surround$exitMovedWhole(int a) {
+        Trace.add("exitMovedWhole " + a);
+    }
+
+    @Surround(method = "movedBody", at = @At(value = "INVOKE", target = TWICE), id = "movedCall")
+    private void surround$enterMovedCall(Callee callee, int b, @Surround.Local(argsOnly = true) int a) {
+        @Surround.Skip boolean skip = a < 0;
+        Trace.add("enterMovedCall " + b + " " + a);
+    }
+
+    @Surround.Skipped("movedCall")
+    private int surround$skippedMovedCall(Callee callee, int b, @Surround.Local(argsOnly = true) int a) {
+        Trace.add("skippedMovedCall " + b + " " + a);
+        return b * 10;
+    }
+
+    @Surround.Finally("movedCall")
+    private void surround$exitMovedCall(Callee callee, int b, @Surround.Local(argsOnly = true) int a) {
+        Trace.add("exitMovedCall " + b + " " + a);
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/integration/mixin/MixinWholeTarget.java

@@ -0,0 +1,389 @@
+package com.gtnewhorizons.angelica.experimental.surround.integration.mixin;
+
+import com.gtnewhorizons.angelica.experimental.surround.Surround;
+import com.gtnewhorizons.angelica.experimental.surround.integration.WholeTarget;
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+@Mixin(value = WholeTarget.class, remap = false)
+public class MixinWholeTarget {
+
+    @Surround(method = "compute(I)I", id = "compute")
+    private void surround$enter(int a) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enter " + a + " " + token);
+    }
+
+    @Surround.Finally("compute")
+    private void surround$exit(@Surround.Carry long token) {
+        Trace.add("exit " + token);
+    }
+
+    @Inject(method = "compute(I)I", at = @At("HEAD"))
+    private void surround$head(int a, CallbackInfoReturnable<Integer> cir) {
+        Trace.add("head " + a);
+    }
+
+    @Inject(method = "compute(I)I", at = @At("RETURN"))
+    private void surround$tail(int a, CallbackInfoReturnable<Integer> cir) {
+        Trace.add("tail " + cir.getReturnValue());
+    }
+
+    @Surround(method = "boom()V", id = "boom")
+    private void surround$enterBoom() {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enterBoom " + token);
+    }
+
+    @Surround.Catch("boom")
+    private void surround$caughtBoomBroad(Throwable e, @Surround.Carry long token) {
+        Trace.add("caughtBroad " + token + " " + e.getMessage());
+    }
+
+    @Surround.Catch("boom")
+    private void surround$caughtBoom(IllegalStateException e, @Surround.Carry long token) {
+        Trace.add("caught " + token + " " + e.getMessage());
+    }
+
+    @Surround.Finally("boom")
+    private void surround$exitBoom(@Surround.Carry long token) {
+        Trace.add("exitBoom " + token);
+    }
+
+    @Inject(method = "boom()V", at = @At("HEAD"))
+    private void surround$boomHead(CallbackInfo ci) {
+        Trace.add("boomHead");
+    }
+
+    @Surround(method = {"alpha()V", "beta()V"}, id = "both")
+    private void surround$enterBoth() {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enterBoth " + token);
+    }
+
+    @Surround.Finally("both")
+    private void surround$exitBoth(@Surround.Carry long token) {
+        Trace.add("exitBoth " + token);
+    }
+
+    @Surround(method = "lockedInstance(I)I", id = "instance")
+    private void surround$enterInstance(int a) {
+        Trace.add("enterInstance " + Thread.holdsLock(this));
+    }
+
+    @Surround.Finally("instance")
+    private void surround$exitInstance() {
+        Trace.add("exitInstance " + Thread.holdsLock(this));
+    }
+
+    @Surround(method = "run()V", id = "run")
+    private void surround$enterRun() {
+        Trace.add("enter");
+    }
+
+    @Unique
+    @Surround.Finally("run")
+    private void exit() {
+        Trace.add("handler exit");
+    }
+
+    @Surround(method = "priority(I)I", id = "priority")
+    private void surround$enterLow(int a) {
+        Trace.add("enterLow");
+    }
+
+    @Surround.Return("priority")
+    private int surround$returnLow(int result) {
+        Trace.add("returnLow " + result);
+        return result + 1;
+    }
+
+    @Surround.Finally("priority")
+    private void surround$exitLow() {
+        Trace.add("exitLow");
+    }
+
+    @Surround(method = "branching(I)I", id = "branching")
+    private void surround$enterBranching(int a) {
+        @Surround.Carry String sign = a < 0 ? "negative" : "positive";
+        Trace.add("enterBranching " + sign);
+    }
+
+    @Surround.Finally("branching")
+    private void surround$exitBranching(int a, @Surround.Carry String sign) {
+        Trace.add("exitBranching " + sign);
+    }
+
+    @Surround(method = "skippedVoid(I)V", id = "skippedVoid")
+    private void surround$enterSkippedVoid(int a) {
+        @Surround.Skip boolean skip = a < 0;
+        Trace.add("enterSkippedVoid " + a);
+    }
+
+    @Surround.Finally("skippedVoid")
+    private void surround$exitSkippedVoid() {
+        Trace.add("exitSkippedVoid");
+    }
+
+    @Surround(method = "reentrant(I)I", id = "reentrant")
+    private void surround$enterReentrant(int a) {
+        @Surround.Carry int direct = 0;
+        @Surround.Skip boolean skip = false;
+        if (!WholeTarget.guard) {
+            WholeTarget.guard = true;
+            direct = ((WholeTarget) (Object) this).reentrant(a + 10);
+            WholeTarget.guard = false;
+            skip = true;
+        }
+        Trace.add("enterReentrant " + a + " " + skip);
+    }
+
+    @Surround.Skipped("reentrant")
+    private int surround$skippedReentrant(int a, @Surround.Carry int direct) {
+        return direct * 2;
+    }
+
+    @Surround.Finally("reentrant")
+    private void surround$exitReentrant(int a) {
+        Trace.add("exitReentrant " + a);
+    }
+
+    @Surround(method = "skipAndReturn(Ljava/lang/String;)Ljava/lang/String;", id = "skipAndReturn")
+    private void surround$enterSkipAndReturn(String a) {
+        @Surround.Skip boolean skip = a.isEmpty();
+        Trace.add("enterSkipAndReturn " + a);
+    }
+
+    @Surround.Skipped("skipAndReturn")
+    private String surround$skippedSkipAndReturn(String a) {
+        Trace.add("skippedSkipAndReturn");
+        return null;
+    }
+
+    @Surround.Return("skipAndReturn")
+    private String surround$returnSkipAndReturn(String result, String a) {
+        Trace.add("returnSkipAndReturn " + result);
+        if (result.equals("x!")) {
+            throw new IllegalStateException("return");
+        }
+        return result + "?";
+    }
+
+    @Surround.Catch("skipAndReturn")
+    private void surround$caughtSkipAndReturn(Throwable e) {
+        Trace.add("caughtSkipAndReturn " + e.getMessage());
+    }
+
+    @Surround.Finally("skipAndReturn")
+    private void surround$exitSkipAndReturn(String a) {
+        Trace.add("exitSkipAndReturn " + a);
+    }
+
+    @Surround(method = "entryCatches(I)I", id = "entryCatches")
+    private static void surround$enterEntryCatches(int a) {
+        @Surround.Carry final boolean direct = !WholeTarget.guard;
+        if (direct) {
+            WholeTarget.guard = true;
+            try {
+                WholeTarget.entryCatches(a);
+            } catch (Throwable t) {
+                WholeTarget.guard = false;
+                Trace.add("entryRethrow " + t.getMessage());
+                throw t;
+            }
+            Trace.add("enterEntryCatches " + a);
+        }
+    }
+
+    @Surround.Finally("entryCatches")
+    private static void surround$exitEntryCatches(@Surround.Carry boolean direct) {
+        if (direct) {
+            WholeTarget.guard = false;
+        }
+        Trace.add("exitEntryCatches " + direct);
+    }
+
+    @Surround(method = "wideBody(DJ)D", id = "wideBody")
+    private static void surround$enterWideBody(double a, long b) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enter " + token);
+    }
+
+    @Surround.Finally("wideBody")
+    private static void surround$exitWideBody(@Surround.Carry long token) {
+        Trace.add("exit " + token);
+    }
+
+    @Surround(method = "throwingEntry(I)V", id = "throwingEntry")
+    private void surround$enterThrowingEntry(int a) {
+        Trace.add("enterThrows " + a);
+        if (a > 0) {
+            throw new IllegalArgumentException("entry failed");
+        }
+    }
+
+    @Surround.Finally("throwingEntry")
+    private void surround$exitThrowingEntry() {
+        Trace.add("exitNothing");
+    }
+
+    @Surround(method = "throwingFinally(II)I", id = "throwingFinally")
+    private void surround$enterThrowingFinally(int a, int b) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enter " + token);
+    }
+
+    @Surround.Finally("throwingFinally")
+    private void surround$exitThrowingFinally(@Surround.Carry long token) {
+        Trace.add("exitThrows " + token);
+        throw new UnsupportedOperationException("finally failed");
+    }
+
+    @Surround(method = "caught(I)I", id = "caught")
+    private void surround$enterCaught(int a) {
+        @Surround.Carry long token = Trace.nextToken();
+        Trace.add("enter " + token);
+    }
+
+    @Surround.Finally("caught")
+    private void surround$exitCaught(@Surround.Carry long token) {
+        Trace.add("exit " + token);
+    }
+
+    @Surround(method = "carryThree(I)I", id = "carryThree")
+    private void surround$enterCarryThree(int a) {
+        @Surround.Carry int count = a + 1;
+        @Surround.Carry long stamp = 100L + a;
+        @Surround.Carry String label = "L" + a;
+        Trace.add("enter " + count + " " + stamp + " " + label);
+    }
+
+    @Surround.Finally("carryThree")
+    private void surround$exitCarryThree(@Surround.Carry String label, @Surround.Carry long stamp, @Surround.Carry int count) {
+        Trace.add("exit " + count + " " + stamp + " " + label);
+    }
+
+    @Surround(method = "carryUninitialized(I)I", id = "carryUninitialized")
+    private void surround$enterCarryUninitialized(int a) {
+        @Surround.Carry String label = new String(a > 0 ? "pos" : "neg");
+        Trace.add("enter " + label);
+    }
+
+    @Surround.Finally("carryUninitialized")
+    private void surround$exitCarryUninitialized(@Surround.Carry String label) {
+        Trace.add("exit " + label);
+    }
+
+    @Surround(method = "carryGuarded(I)I", id = "carryGuarded")
+    private void surround$enterCarryGuarded(int a) {
+        @Surround.Carry int state = 0;
+        try {
+            state = WholeTarget.risky(a);
+        } catch (IllegalArgumentException e) {
+            state = -1;
+            Trace.add("recovered");
+        }
+        Trace.add("enter " + state);
+    }
+
+    @Surround.Finally("carryGuarded")
+    private void surround$exitCarryGuarded(@Surround.Carry int flag) {
+        Trace.add("exit " + flag);
+    }
+
+    @Surround(method = "carrySplitAtEnd(I)I", id = "carrySplitAtEnd")
+    private void surround$enterCarrySplitAtEnd(int a) {
+        @Surround.Carry int flag;
+        if (a > 0) {
+            flag = 1;
+        } else {
+            flag = 2;
+        }
+    }
+
+    @Surround.Finally("carrySplitAtEnd")
+    private void surround$exitCarrySplitAtEnd(@Surround.Carry int flag) {
+        Trace.add("exit " + flag);
+    }
+
+    @Surround(method = "carryWideBeforeFrame(I)I", id = "carryWideBeforeFrame")
+    private void surround$enterCarryWideBeforeFrame(int a) {
+        @Surround.Carry long stamp = a;
+        @Surround.Carry int count = a + 1;
+        if (a > 0) {
+            Trace.add("positive");
+        }
+    }
+
+    @Surround.Finally("carryWideBeforeFrame")
+    private void surround$exitCarryWideBeforeFrame(@Surround.Carry long stamp, @Surround.Carry int count) {
+        Trace.add("exit " + stamp + " " + count);
+    }
+
+    @Surround(method = "carryArrays(I)I", id = "carryArrays")
+    private void surround$enterCarryArrays(int a) {
+        @Surround.Carry("elements") int[] elements = {a};
+        String @Surround.Carry("names") [] names = {"n" + a};
+    }
+
+    @Surround.Finally("carryArrays")
+    private void surround$exitCarryArrays(@Surround.Carry("names") String[] names, @Surround.Carry("elements") int[] elements) {
+        Trace.add("exit " + names[0] + " " + elements[0]);
+    }
+
+    @Surround(method = "reused(I)I", id = "reused")
+    private void surround$enterReused(int a) {
+        {
+            int tmp = a + 5;
+            Trace.add("tmp " + tmp);
+        }
+        @Surround.Carry long prev = a + 7;
+        Trace.add("enter " + prev);
+    }
+
+    @Surround.Finally("reused")
+    private void surround$exitPrev(@Surround.Carry long prev) {
+        Trace.add("exit " + prev);
+    }
+
+    @Surround(method = "throwWide(I)V", id = "throwWide")
+    private void surround$enterThrowWide(int a) {
+        @Surround.Carry long first = a + 1L;
+        String scratch = "s" + a;
+        @Surround.Carry double second = a / 2.0d;
+        @Surround.Carry int third = a;
+        Trace.add("enter " + first + " " + second + " " + third + " " + scratch);
+    }
+
+    @Surround.Catch("throwWide")
+    private void surround$caughtThrowWide(Throwable e, @Surround.Carry long first, @Surround.Carry double second, @Surround.Carry int third) {
+        Trace.add("caught " + first + " " + second + " " + third);
+    }
+
+    @Surround.Finally("throwWide")
+    private void surround$exitThrowWide(@Surround.Carry double second, @Surround.Carry int third, @Surround.Carry long first) {
+        Trace.add("exit " + first + " " + second + " " + third);
+    }
+
+    @Surround(method = "throwObject(I)V", id = "throwObject")
+    private void surround$enterThrowObject(int a) {
+        @Surround.Carry Object prev = WholeTarget.asObject("o" + a);
+        Trace.add("enter " + prev);
+    }
+
+    @Surround.Catch("throwObject")
+    private void surround$caughtThrowObject(IllegalStateException e, @Surround.Carry String prev) {
+        Trace.add("caught " + prev.length() + " " + prev);
+        throw new UnsupportedOperationException("replaced", e);
+    }
+
+    @Surround.Finally("throwObject")
+    private void surround$exitThrowObject(@Surround.Carry String prev) {
+        Trace.add("exit " + prev.length() + " " + prev);
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/integration/mixin/MixinWholeTargetHigh.java

@@ -0,0 +1,26 @@
+package com.gtnewhorizons.angelica.experimental.surround.integration.mixin;
+
+import com.gtnewhorizons.angelica.experimental.surround.Surround;
+import com.gtnewhorizons.angelica.experimental.surround.integration.WholeTarget;
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import org.spongepowered.asm.mixin.Mixin;
+
+@Mixin(value = WholeTarget.class, priority = 1100, remap = false)
+public class MixinWholeTargetHigh {
+
+    @Surround(method = "priority(I)I")
+    private void surround$enterHigh(int a) {
+        Trace.add("enterHigh");
+    }
+
+    @Surround.Return
+    private int surround$returnHigh(int result) {
+        Trace.add("returnHigh " + result);
+        return result * 10;
+    }
+
+    @Surround.Finally
+    private void surround$exitHigh() {
+        Trace.add("exitHigh");
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/integration/mixinextras/MixinWrapTarget.java

@@ -0,0 +1,70 @@
+package com.gtnewhorizons.angelica.experimental.surround.integration.mixinextras;
+
+import com.gtnewhorizons.angelica.experimental.surround.Surround;
+import com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.Callee;
+import com.gtnewhorizons.angelica.experimental.surround.integration.WrapTarget;
+import com.gtnewhorizons.angelica.experimental.surround.targets.Trace;
+import com.llamalad7.mixinextras.injector.wrapmethod.WrapMethod;
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
+import com.llamalad7.mixinextras.sugar.Share;
+import com.llamalad7.mixinextras.sugar.ref.LocalIntRef;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+
+import static com.gtnewhorizons.angelica.experimental.surround.integration.CallTarget.TWICE;
+
+@Mixin(value = WrapTarget.class, remap = false)
+public class MixinWrapTarget {
+
+    @Surround(method = "wrapped", id = "wrapped")
+    private void surround$enterWrapped(int a) {
+        Trace.add("entry " + a);
+    }
+
+    @Surround.Finally("wrapped")
+    private void surround$exitWrapped() {
+        Trace.add("finally");
+    }
+
+    @WrapMethod(method = "wrapped")
+    private int wrapWrapped(int a, Operation<Integer> original) {
+        Trace.add("wrap-before " + a);
+        final int result = original.call(a);
+        Trace.add("wrap-after " + result);
+        return result;
+    }
+
+    @WrapOperation(method = "originalOperands", at = @At(value = "INVOKE", target = TWICE))
+    private int wrapOperation$shiftArgument(Callee callee, int a, Operation<Integer> original) {
+        Trace.add("wrap " + a);
+        return original.call(callee, a + 100);
+    }
+
+    @Surround(method = "originalOperands", at = @At(value = "INVOKE", target = TWICE), id = "originalOperands")
+    private void surround$enterOriginalOperands(Callee callee, int a) {
+        Trace.add("enter " + a);
+    }
+
+    @Surround.Finally("originalOperands")
+    private void surround$exitOriginalOperands(Callee callee, int a) {
+        Trace.add("exit " + a);
+    }
+
+    @WrapMethod(method = "shifted")
+    private int wrapShifted(int a, Operation<Integer> original, @Share("seen") LocalIntRef seen) {
+        seen.set(a);
+        Trace.add("wrap " + a);
+        return original.call(a);
+    }
+
+    @Surround(method = "shifted", at = @At(value = "INVOKE", target = TWICE), id = "shifted")
+    private void surround$enterShifted(Callee callee, int value, @Surround.Local(ordinal = 1) int local, @Surround.Local String label) {
+        Trace.add("enterShifted " + value + " " + local + " " + label);
+    }
+
+    @Surround.Finally("shifted")
+    private void surround$exitShifted(@Surround.Local(name = "local") int local, @Surround.Local String label) {
+        Trace.add("exitShifted " + local + " " + label);
+    }
+}

experimental-surround/runtime/src/test/java/com/gtnewhorizons/angelica/experimental/surround/targets/Trace.java

@@ -0,0 +1,32 @@
+package com.gtnewhorizons.angelica.experimental.surround.targets;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+public final class Trace {
+
+    private static final List<String> EVENTS = new ArrayList<>();
+    private static long counter;
+
+    private Trace() {
+    }
+
+    public static void reset() {
+        EVENTS.clear();
+        counter = 0;
+    }
+
+    public static void add(String event) {
+        EVENTS.add(event);
+    }
+
+    public static void assertEvents(String... expected) {
+        assertArrayEquals(expected, EVENTS.toArray(new String[EVENTS.size()]), EVENTS.toString());
+    }
+
+    public static long nextToken() {
+        return ++counter;
+    }
+}

experimental-surround/runtime/src/test/resources/golden/call-handle.asm

@@ -0,0 +1,79 @@
+// class version 52.0 (52)
+// access flags 0x21
+public class com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget {
+
+
+  // access flags 0x1
+  public valueBelow(I)I
+    TRYCATCHBLOCK L0 L1 L2 java/lang/IllegalStateException
+    TRYCATCHBLOCK L3 L4 L5 null
+    TRYCATCHBLOCK L0 L1 L5 null
+   L6
+    ILOAD 1
+    ALOAD 0
+    GETFIELD com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.callee : Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;
+    ILOAD 1
+    ISTORE 3
+    ASTORE 2
+    ISTORE 4
+   L7
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/targets/Trace.nextToken ()J
+    LSTORE 5
+   L8
+    ILOAD 3
+    LLOAD 5
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.md$jvmdowngrader$concat$surround$enterValueBelow$1$3f (IJ)Ljava/lang/String;
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/targets/Trace.add (Ljava/lang/String;)V
+   L9
+    ILOAD 4
+    ALOAD 2
+    ILOAD 3
+   L0
+    INVOKEVIRTUAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee.explode (I)I
+   L1
+    ALOAD 0
+    ALOAD 2
+    ILOAD 3
+    LLOAD 5
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.surround$exitValueBelow (Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;IJ)V
+    GOTO L10
+   L2
+   FRAME FULL [com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget I com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee I I J] [java/lang/IllegalStateException]
+    ASTORE 7
+    ILOAD 4
+   L3
+    ALOAD 0
+    ALOAD 7
+    ALOAD 2
+    ILOAD 3
+    LLOAD 5
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.surround$handleValueBelow (Ljava/lang/IllegalStateException;Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;IJ)I
+   L4
+    ALOAD 0
+    ALOAD 2
+    ILOAD 3
+    LLOAD 5
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.surround$exitValueBelow (Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;IJ)V
+    GOTO L10
+   L5
+   FRAME SAME1 java/lang/Throwable
+    ASTORE 7
+    ALOAD 0
+    ALOAD 2
+    ILOAD 3
+    LLOAD 5
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.surround$exitValueBelow (Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;IJ)V
+    ALOAD 7
+    ATHROW
+   L10
+   FRAME FULL [com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget I com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee I I J] [I I]
+    BIPUSH 10
+    IMUL
+    IADD
+    IRETURN
+   L11
+    LOCALVARIABLE this Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget; L6 L11 0
+    LOCALVARIABLE a I L6 L11 1
+    MAXSTACK = 7
+    MAXLOCALS = 8
+}

experimental-surround/runtime/src/test/resources/golden/call-skip.asm

@@ -0,0 +1,71 @@
+// class version 52.0 (52)
+// access flags 0x21
+public class com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget {
+
+
+  // access flags 0x1
+  public valueSkip(I)I
+    TRYCATCHBLOCK L0 L1 L2 null
+   L3
+    ALOAD 0
+    GETFIELD com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.callee : Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;
+    ILOAD 1
+    ISTORE 3
+    ASTORE 2
+   L4
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/targets/Trace.nextToken ()J
+    LSTORE 4
+   L5
+    ILOAD 3
+    IFGE L6
+    ICONST_1
+    GOTO L7
+   L6
+   FRAME APPEND [com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee I J]
+    ICONST_0
+   L7
+   FRAME SAME1 I
+    ISTORE 6
+   L8
+    ILOAD 3
+    LLOAD 4
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.md$jvmdowngrader$concat$surround$enterValueSkip$1$50 (IJ)Ljava/lang/String;
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/targets/Trace.add (Ljava/lang/String;)V
+   L9
+    ILOAD 6
+    IFEQ L10
+   L0
+    ALOAD 0
+    ALOAD 2
+    ILOAD 3
+    LLOAD 4
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.surround$skippedValueSkip (Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee;IJ)I
+    GOTO L1
+   L10
+   FRAME APPEND [I]
+    ALOAD 2
+    ILOAD 3
+    INVOKEVIRTUAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget$Callee.twice (I)I
+   L1
+   FRAME SAME1 I
+    ALOAD 0
+    LLOAD 4
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.surround$exitValueSkip (J)V
+    GOTO L11
+   L2
+   FRAME SAME1 java/lang/Throwable
+    ASTORE 7
+    ALOAD 0
+    LLOAD 4
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/CallTarget.surround$exitValueSkip (J)V
+    ALOAD 7
+    ATHROW
+   L11
+   FRAME SAME1 I
+    IRETURN
+   L12
+    LOCALVARIABLE this Lcom/gtnewhorizons/angelica/experimental/surround/integration/CallTarget; L3 L12 0
+    LOCALVARIABLE a I L3 L12 1
+    MAXSTACK = 5
+    MAXLOCALS = 8
+}

experimental-surround/runtime/src/test/resources/golden/whole-skip-return.asm

@@ -0,0 +1,93 @@
+// class version 52.0 (52)
+// access flags 0x21
+public class com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget {
+
+
+  // access flags 0x1
+  public skipAndReturn(Ljava/lang/String;)Ljava/lang/String;
+    TRYCATCHBLOCK L0 L1 L2 java/lang/Throwable
+    TRYCATCHBLOCK L3 L4 L5 null
+    TRYCATCHBLOCK L1 L6 L5 null
+    TRYCATCHBLOCK L0 L1 L5 null
+   L7
+    ALOAD 1
+    INVOKEVIRTUAL java/lang/String.isEmpty ()Z
+    ISTORE 2
+   L8
+    ALOAD 1
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.md$jvmdowngrader$concat$surround$enterSkipAndReturn$1 (Ljava/lang/String;)Ljava/lang/String;
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/targets/Trace.add (Ljava/lang/String;)V
+   L9
+    ILOAD 2
+    IFEQ L10
+   L0
+    ALOAD 0
+    ALOAD 1
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.surround$skippedSkipAndReturn (Ljava/lang/String;)Ljava/lang/String;
+    GOTO L6
+   L10
+   FRAME APPEND [I]
+    ALOAD 0
+    ALOAD 1
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.skipAndReturn$surround (Ljava/lang/String;)Ljava/lang/String;
+   L1
+    ASTORE 4
+    ALOAD 0
+    ALOAD 4
+    ALOAD 1
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.surround$returnSkipAndReturn (Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
+   L6
+   FRAME SAME1 java/lang/String
+    ALOAD 0
+    ALOAD 1
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.surround$exitSkipAndReturn (Ljava/lang/String;)V
+    GOTO L11
+   L2
+   FRAME SAME1 java/lang/Throwable
+    ASTORE 3
+   L3
+    ALOAD 0
+    ALOAD 3
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.surround$caughtSkipAndReturn (Ljava/lang/Throwable;)V
+   L4
+    ALOAD 0
+    ALOAD 1
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.surround$exitSkipAndReturn (Ljava/lang/String;)V
+    ALOAD 3
+    ATHROW
+   L5
+   FRAME SAME1 java/lang/Throwable
+    ASTORE 3
+    ALOAD 0
+    ALOAD 1
+    INVOKESPECIAL com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.surround$exitSkipAndReturn (Ljava/lang/String;)V
+    ALOAD 3
+    ATHROW
+   L11
+   FRAME SAME1 java/lang/String
+    ARETURN
+   L12
+    LOCALVARIABLE this Lcom/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget; L7 L12 0
+    LOCALVARIABLE a Ljava/lang/String; L7 L12 1
+    LOCALVARIABLE skip Z L8 L9 2
+    LOCALVARIABLE surround$error Ljava/lang/Throwable; L2 L12 3
+    LOCALVARIABLE surround$result Ljava/lang/String; L1 L6 4
+    MAXSTACK = 3
+    MAXLOCALS = 5
+
+  // access flags 0x2
+  private skipAndReturn$surround(Ljava/lang/String;)Ljava/lang/String;
+   L0
+    ALOAD 1
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.jvmdowngrader$concat$skipAndReturn$1 (Ljava/lang/String;)Ljava/lang/String;
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/targets/Trace.add (Ljava/lang/String;)V
+   L1
+    ALOAD 1
+    INVOKESTATIC com/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget.jvmdowngrader$concat$skipAndReturn$2 (Ljava/lang/String;)Ljava/lang/String;
+    ARETURN
+   L2
+    LOCALVARIABLE this Lcom/gtnewhorizons/angelica/experimental/surround/integration/WholeTarget; L0 L2 0
+    LOCALVARIABLE a Ljava/lang/String; L0 L2 1
+    MAXSTACK = 1
+    MAXLOCALS = 2
+}

experimental-surround/runtime/src/test/resources/mixins.surround.mixinextras.test.json

@@ -0,0 +1,9 @@
+{
+  "required": true,
+  "minVersion": "0.8",
+  "package": "com.gtnewhorizons.angelica.experimental.surround.integration.mixinextras",
+  "compatibilityLevel": "JAVA_8",
+  "mixins": [
+    "MixinWrapTarget"
+  ]
+}

experimental-surround/runtime/src/test/resources/mixins.surround.test.json

@@ -0,0 +1,11 @@
+{
+  "required": true,
+  "minVersion": "0.8",
+  "package": "com.gtnewhorizons.angelica.experimental.surround.integration.mixin",
+  "compatibilityLevel": "JAVA_8",
+  "mixins": [
+    "MixinCallTarget",
+    "MixinWholeTarget",
+    "MixinWholeTargetHigh"
+  ]
+}

experimental-surround/surround.project.gradle.kts

@@ -0,0 +1,15 @@
+extensions.getByType<JavaPluginExtension>().apply {
+    toolchain.languageVersion.set(JavaLanguageVersion.of(25))
+}
+
+repositories {
+    maven {
+        name = "GTNH Maven"
+        url = uri("https://nexus.gtnewhorizons.com/repository/public/")
+    }
+    maven {
+        name = "Minecraft Libraries"
+        url = uri("https://libraries.minecraft.net")
+    }
+    mavenCentral()
+}

experimental-surround/surround.root.gradle.kts

@@ -0,0 +1,13 @@
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+
+dependencies {
+    add("shadowImplementation", project(":experimental-surround-runtime")) { isTransitive = false }
+    add("mixinAnnotationProcessor", project(":experimental-surround-ap"))
+}
+
+tasks.named<ShadowJar>("shadowJar") {
+    minimize {
+        exclude(project(":experimental-surround-runtime"))
+    }
+    relocate("com.gtnewhorizons.angelica.experimental.surround", "com.gtnewhorizons.angelica.experimental.surround")
+}

experimental-surround/surround.settings.gradle.kts

@@ -0,0 +1,3 @@
+include("experimental-surround-runtime", "experimental-surround-ap")
+project(":experimental-surround-runtime").projectDir = file("runtime")
+project(":experimental-surround-ap").projectDir = file("ap")

glsm/build.gradle.kts

@@ -320,6 +320,7 @@ val spirvTest by tasks.registering(Test::class) {
     filter {
         includeTestsMatching("com.gtnewhorizons.angelica.glsm.shader.SpirvShaderTranslator*Test")
         includeTestsMatching("com.gtnewhorizons.angelica.glsm.ffp.FFPUniformBlockSpirvLayoutTest")
+        includeTestsMatching("com.gtnewhorizons.angelica.glsm.shader.SpirvCompilerDiskCacheTest")
     }
 
     // libshaderc.so / libspirv-cross.so are extracted by extractNatives3.

glsm/src/main/java/com/gtnewhorizons/angelica/config/SystemProperties.java

@@ -64,6 +64,10 @@ public final class SystemProperties {
     public static final FlybyPacing FLYBY_PACING = parseEnum("angelica.flyby.pacing", FlybyPacing.UNCAPPED, FlybyPacing.UNCAPPED, FlybyPacing.class);
     public static final FlybyWeather FLYBY_WEATHER = parseEnum("angelica.flyby.weather", FlybyWeather.CLEAR, FlybyWeather.CLEAR, FlybyWeather.class);
     public static final boolean FLYBY_JFR = Boolean.getBoolean("angelica.flyby.jfr");
+    public static final float FLYBY_PITCH = parseFloat("angelica.flyby.pitch");
+    public static final int FLYBY_SCREENSHOTS = Integer.getInteger("angelica.flyby.screenshots", 0);
+    public static final boolean FLYBY_DEBUG_HUD = Boolean.getBoolean("angelica.flyby.debugHud");
+    public static final String FLYBY_CRASH_TEST = System.getProperty("angelica.flyby.crashTest", "");
 
     // Debug
     public static final boolean LWJGL_DEBUG = Boolean.getBoolean("org.lwjgl.util.Debug");
@@ -167,6 +171,16 @@ public final class SystemProperties {
         }
     }
 
+    private static float parseFloat(String key) {
+        final String raw = System.getProperty(key);
+        if (raw == null || raw.isEmpty()) return Float.NaN;
+        try {
+            return Float.parseFloat(raw);
+        } catch (NumberFormatException e) {
+            return Float.NaN;
+        }
+    }
+
     public static boolean isDeobf() {
         return Launch.blackboard != null && Boolean.TRUE.equals(Launch.blackboard.get("fml.deobfuscatedEnvironment"));
     }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/CompatShaderTransformer.java

@@ -3,6 +3,7 @@ package com.gtnewhorizons.angelica.glsm;
 import com.gtnewhorizon.gtnhlib.client.renderer.vertex.VertexFormatElement.Usage;
 import com.gtnewhorizons.angelica.config.SystemProperties;
 import com.gtnewhorizons.angelica.glsm.backend.RenderBackend;
+import com.gtnewhorizons.angelica.glsm.shader.ShaderDiskCache;
 import com.gtnewhorizons.angelica.glsm.shader.SpirvShaderTranslator;
 import org.antlr.v4.runtime.tree.ParseTree;
 import org.antlr.v4.runtime.tree.TerminalNode;
@@ -139,12 +140,20 @@ public class CompatShaderTransformer {
             if (cached != null) {
                 result = cached;
             } else {
-                try {
-                    result = transformInternal(source, isFragment);
+                final ShaderDiskCache.Key dk = ShaderDiskCache.isEnabled() ? diskKey(source, isFragment) : null;
+                final String disk = dk != null ? ShaderDiskCache.getString(dk) : null;
+                if (disk != null) {
+                    result = disk;
                     cache.put(key, result);
-                } catch (Exception e) {
-                    GLStateManager.LOGGER.warn("CompatShaderTransformer: AST transformation failed, falling back to version fixup only", e);
-                    result = fixupVersion(source);
+                } else {
+                    try {
+                        result = transformInternal(source, isFragment);
+                        cache.put(key, result);
+                        if (dk != null) ShaderDiskCache.putString(dk, result);
+                    } catch (Exception e) {
+                        GLStateManager.LOGGER.warn("CompatShaderTransformer: AST transformation failed, falling back to version fixup only", e);
+                        result = fixupVersion(source);
+                    }
                 }
             }
         }
@@ -164,6 +173,14 @@ public class CompatShaderTransformer {
         return result;
     }
 
+    private static int minGlslVersion() {
+        return RENDER_BACKEND != null ? RENDER_BACKEND.getMinGLSLVersion() : 330;
+    }
+
+    static ShaderDiskCache.Key diskKey(String source, boolean isFragment) {
+        return ShaderDiskCache.key("compat").str(source).b(isFragment).i(minGlslVersion());
+    }
+
     public static boolean isCoreShader(String source) {
         final Matcher vm = VERSION_PATTERN.matcher(source);
         if (vm.find()) {
@@ -186,7 +203,7 @@ public class CompatShaderTransformer {
             declaredVersion = Integer.parseInt(versionMatcher.group(1));
         }
 
-        final int targetVersion = Math.max(declaredVersion, RENDER_BACKEND != null ? RENDER_BACKEND.getMinGLSLVersion() : 330);
+        final int targetVersion = Math.max(declaredVersion, minGlslVersion());
 
         // Pre-parse reserved word renaming - prevents ANTLR parse failures
         source = GlslTransformUtils.replaceTexture(source);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/GLContextState.java

@@ -21,6 +21,7 @@ import com.gtnewhorizons.angelica.glsm.stacks.MaterialStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.MatrixModeStack;
 import com.gtnewhorizons.angelica.glsm.stacks.PointStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.PolygonStateStack;
+import com.gtnewhorizons.angelica.glsm.stacks.RetainedState;
 import com.gtnewhorizons.angelica.glsm.stacks.ScissorStateStack;
 import com.gtnewhorizons.angelica.glsm.stacks.StackIdAllocator;
 import com.gtnewhorizons.angelica.glsm.stacks.StencilStateStack;
@@ -106,7 +107,16 @@ public class GLContextState {
     public int maxBoundTextureUnit = 0;
     public int maxBoundImageUnit = 0;
     public final StateSet[] attribSets = new StateSet[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
+    public RetainedState retainedOwner;
     public int attribDepth = 0;
+
+    public boolean savesState(int id) {
+        for (int i = attribDepth - 1; i >= 0; i--) {
+            if (attribSets[i].contains(id)) return true;
+        }
+        return false;
+    }
+
     public int batchStateGeneration;
     public final int[] savedBatchStateGen = new int[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
     public CowStateStack<?>[] stackById;
@@ -242,6 +252,9 @@ public class GLContextState {
     public int internalGlDepth;
     public int internalDrawDepth;
     public int savedFilterTextureId;
+    public int savedFilterMin = -1;
+    public int savedFilterMag = -1;
+    public float savedFilterAniso = -1.0f;
     public boolean wideLineEmulationActive = false;
     public boolean lineStippleActive = false;
     public Instancing ffpInstancing = Instancing.NONE;

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/GlslTransformUtils.java

@@ -49,11 +49,11 @@ public class GlslTransformUtils {
     private static final Map<Integer, List<ReservedWordRename>> VERSIONED_RESERVED_WORDS = Map.of(
         // Some reserved words to always rename
         0, List.of(
-            new ReservedWordRename(Pattern.compile("\\bsample\\b"), RENAMED_PREFIX + "sample"),
-            new ReservedWordRename(Pattern.compile("\\bnew\\b"), RENAMED_PREFIX + "new")
+            new ReservedWordRename(Pattern.compile("sample(?<=\\bsample)\\b"), RENAMED_PREFIX + "sample"),
+            new ReservedWordRename(Pattern.compile("new(?<=\\bnew)\\b"), RENAMED_PREFIX + "new")
         ),
         400, List.of(
-            new ReservedWordRename(Pattern.compile("\\bsampler\\b(?!\\d)"), RENAMED_PREFIX + "sampler")
+            new ReservedWordRename(Pattern.compile("sampler(?<=\\bsampler)\\b(?!\\d)"), RENAMED_PREFIX + "sampler")
         )
     );
 

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/LightingSnapshot.java

@@ -0,0 +1,26 @@
+package com.gtnewhorizons.angelica.glsm;
+
+import com.gtnewhorizons.angelica.glsm.ffp.VertexKey;
+import com.gtnewhorizons.angelica.glsm.states.LightModelState;
+import com.gtnewhorizons.angelica.glsm.states.LightState;
+import com.gtnewhorizons.angelica.glsm.states.MaterialState;
+import org.lwjgl.opengl.GL11;
+
+public final class LightingSnapshot {
+    final boolean[] lightEnabled = new boolean[VertexKey.FFP_LIGHT_COUNT];
+    final LightState[] lights = new LightState[VertexKey.FFP_LIGHT_COUNT];
+    final LightModelState lightModel = new LightModelState();
+    final MaterialState frontMaterial = new MaterialState(GL11.GL_FRONT);
+    final MaterialState backMaterial = new MaterialState(GL11.GL_BACK);
+    boolean colorMaterial;
+    int colorMaterialFace;
+    int colorMaterialParameter;
+    boolean normalize;
+    boolean rescaleNormal;
+
+    public LightingSnapshot() {
+        for (int i = 0; i < lights.length; i++) {
+            lights[i] = new LightState(GL11.GL_LIGHT0 + i);
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/RenderSystem.java

@@ -48,6 +48,7 @@ public class RenderSystem {
     private static boolean supportsClearTexture;
     private static boolean supportsTesselation;
     private static boolean supportsSamplerObjects;
+    private static boolean supportsProgramBinary;
     private static int maxImageUnits;
     @Getter private static int maxCombinedTextureImageUnits;
     private static int maxSSBOBindings;
@@ -159,6 +160,9 @@ public class RenderSystem {
             maxCombinedTextureImageUnits = RENDER_BACKEND.getInteger(GL20.GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS);
         }
 
+        supportsProgramBinary = RENDER_BACKEND.supportsProgramBinary();
+        GLStateManager.LOGGER.info("Program Binary: {}", supportsProgramBinary);
+
         maxGlslVersion = Integer.parseInt(parseGlVersionString(RENDER_BACKEND.getString(GL20.GL_SHADING_LANGUAGE_VERSION)));
         supportsGpuShader4 = GLStateManager.capabilities.GL_EXT_gpu_shader4;
 
@@ -586,18 +590,6 @@ public class RenderSystem {
         RENDER_BACKEND.clearTexImage(texture, level, format, type);
     }
 
-    public static void textureStorage1D(int texture, int target, int levels, int internalFormat, int width) {
-        dsaState.textureStorage1D(texture, target, levels, internalFormat, width);
-    }
-
-    public static void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height) {
-        dsaState.textureStorage2D(texture, target, levels, internalFormat, width, height);
-    }
-
-    public static void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth) {
-        dsaState.textureStorage3D(texture, target, levels, internalFormat, width, height, depth);
-    }
-
     public static int getMaxGlslVersion() {
         return maxGlslVersion;
     }
@@ -623,6 +615,10 @@ public class RenderSystem {
         return supportsSamplerObjects;
     }
 
+    public static boolean supportsProgramBinary() {
+        return supportsProgramBinary;
+    }
+
     public static int genSampler() {
         if (!supportsSamplerObjects) return 0;
         return GLStateManager.glGenSamplers();

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/StateSet.java

@@ -88,10 +88,15 @@ public final class StateSet {
                 GLStateManager.getActiveTextureUnitStack(),
                 GLStateManager.getBlendMode(), GLStateManager.getAlphaTest(), GLStateManager.getDepthTest(),
                 GLStateManager.getLightingState(), GLStateManager.getCullState(), GLStateManager.getPolygonOffsetFillState(),
-                GLStateManager.getTextures().getTextureUnitStates(0)
+                GLStateManager.getTextures().getTextureUnitStates(0), GLStateManager.getTextures().getTextureUnitStates(1),
+                GLStateManager.getLightStates()[0], GLStateManager.getLightStates()[1],
+                GLStateManager.getLightDataStates()[0], GLStateManager.getLightDataStates()[1],
+                GLStateManager.getColorMaterial(), GLStateManager.getColorMaterialFace(), GLStateManager.getColorMaterialParameter(),
+                GLStateManager.getLightModel(), GLStateManager.getFrontMaterial(), GLStateManager.getBackMaterial(),
+                GLStateManager.getNormalizeState(), GLStateManager.getRescaleNormalState()
             ),
             R_BLEND | R_DEPTH | R_COLOR_MASK | R_POLYGON | R_TEXTURE | R_ACTIVE_UNIT,
-            B_FRAG_COLORBUF,
+            B_FRAG_COLORBUF | B_LIGHTING,
             true);
     }
 
@@ -102,9 +107,11 @@ public final class StateSet {
                 GLStateManager.getTextures().getTextureUnitBindings(0), GLStateManager.getTextures().getTextureUnitBindings(1),
                 GLStateManager.getActiveTextureUnitStack(), GLStateManager.getProgramStack(),
                 GLStateManager.getBlendMode(), GLStateManager.getAlphaTest(), GLStateManager.getDepthTest(),
-                GLStateManager.getTextures().getTextureUnitStates(0)
+                GLStateManager.getTextures().getTextureUnitStates(0),
+                GLStateManager.getColorMask(), GLStateManager.getCullState(),
+                GLStateManager.getPolygonState(), GLStateManager.getPolygonOffsetFillState()
             ),
-            R_BLEND | R_DEPTH | R_TEXTURE | R_ACTIVE_UNIT | R_PROGRAM,
+            R_BLEND | R_DEPTH | R_COLOR_MASK | R_TEXTURE | R_ACTIVE_UNIT | R_PROGRAM | R_POLYGON,
             0,
             true);
     }
@@ -116,9 +123,11 @@ public final class StateSet {
                 GLStateManager.getTextures().getTextureUnitBindings(0), GLStateManager.getTextures().getTextureUnitBindings(1),
                 GLStateManager.getActiveTextureUnitStack(),
                 GLStateManager.getBlendMode(), GLStateManager.getAlphaTest(), GLStateManager.getDepthTest(),
-                GLStateManager.getTextures().getTextureUnitStates(0)
+                GLStateManager.getTextures().getTextureUnitStates(0),
+                GLStateManager.getColorMask(), GLStateManager.getCullState(),
+                GLStateManager.getPolygonState(), GLStateManager.getPolygonOffsetFillState()
             ),
-            R_BLEND | R_DEPTH | R_TEXTURE | R_ACTIVE_UNIT,
+            R_BLEND | R_DEPTH | R_COLOR_MASK | R_TEXTURE | R_ACTIVE_UNIT | R_POLYGON,
             0,
             true);
     }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/backend/Lwjgl2GLRenderBackend.java

@@ -1,6 +1,7 @@
 package com.gtnewhorizons.angelica.glsm.backend;
 
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.RenderSystem;
 import org.lwjgl.BufferUtils;
 import org.lwjgl.opengl.AMDDebugOutput;
 import org.lwjgl.opengl.AMDDebugOutputCallback;
@@ -23,6 +24,7 @@ import org.lwjgl.opengl.GL20;
 import org.lwjgl.opengl.GL30;
 import org.lwjgl.opengl.GL31;
 import org.lwjgl.opengl.GL40;
+import org.lwjgl.opengl.GL41;
 import org.lwjgl.opengl.GL32;
 import org.lwjgl.opengl.GL33;
 import org.lwjgl.opengl.GL42;
@@ -807,6 +809,28 @@ public final class Lwjgl2GLRenderBackend extends RenderBackend {
         return GL20.glIsProgram(obj);
     }
 
+    @Override
+    public boolean supportsProgramBinary() {
+        final ContextCapabilities caps = GLStateManager.capabilities;
+        return !RenderSystem.isGLES() && (caps.OpenGL41 || caps.GL_ARB_get_program_binary)
+            && GL11.glGetInteger(GL41.GL_NUM_PROGRAM_BINARY_FORMATS) > 0;
+    }
+
+    @Override
+    public void programParameteri(int program, int pname, int value) {
+        GL41.glProgramParameteri(program, pname, value);
+    }
+
+    @Override
+    public void getProgramBinary(int program, IntBuffer length, IntBuffer binaryFormat, ByteBuffer binary) {
+        GL41.glGetProgramBinary(program, length, binaryFormat, binary);
+    }
+
+    @Override
+    public void programBinary(int program, int binaryFormat, ByteBuffer binary) {
+        GL41.glProgramBinary(program, binaryFormat, binary);
+    }
+
     @Override
     public void validateProgram(int program) {
         GL20.glValidateProgram(program);
@@ -1254,31 +1278,6 @@ public final class Lwjgl2GLRenderBackend extends RenderBackend {
         GL42.glTexStorage2D(target, levels, internalFormat, width, height);
     }
 
-    @Override
-    public void textureStorage2D(int texture, int levels, int internalFormat, int width, int height) {
-        ARBDirectStateAccess.glTextureStorage2D(texture, levels, internalFormat, width, height);
-    }
-
-    @Override
-    public void texStorage1D(int target, int levels, int internalFormat, int width) {
-        GL42.glTexStorage1D(target, levels, internalFormat, width);
-    }
-
-    @Override
-    public void texStorage3D(int target, int levels, int internalFormat, int width, int height, int depth) {
-        GL42.glTexStorage3D(target, levels, internalFormat, width, height, depth);
-    }
-
-    @Override
-    public void textureStorage1D(int texture, int levels, int internalFormat, int width) {
-        ARBDirectStateAccess.glTextureStorage1D(texture, levels, internalFormat, width);
-    }
-
-    @Override
-    public void textureStorage3D(int texture, int levels, int internalFormat, int width, int height, int depth) {
-        ARBDirectStateAccess.glTextureStorage3D(texture, levels, internalFormat, width, height, depth);
-    }
-
     @Override
     public void generateTextureMipmap(int texture) {
         ARBDirectStateAccess.glGenerateTextureMipmap(texture);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/backend/MainThreadPump.java

@@ -34,6 +34,11 @@ public final class MainThreadPump {
     private Throwable failure;
     private ClassLoader callerLoader;
 
+    private boolean presentPumpPending;
+    private boolean presentInFlight;
+    private Throwable presentFailure;
+    private ClassLoader presentLoader;
+
     public MainThreadPump(Executor mainExecutor, BooleanSupplier isMainThread, Runnable pumpBody, Runnable pollBody) {
         this.mainExecutor = mainExecutor;
         this.isMainThread = isMainThread;
@@ -48,7 +53,11 @@ public final class MainThreadPump {
                 pumpBody.run();
             } else {
                 synchronized (lock) {
-                    runPumpOnMainThread();
+                    await(true);
+                    final Throwable t = presentFailure;
+                    presentFailure = null;
+                    if (t != null) throw asUnchecked(t);
+                    if (!presentInFlight) runPumpOnMainThread();
                 }
             }
             pollBody.run();
@@ -60,47 +69,86 @@ public final class MainThreadPump {
     private void runPumpOnMainThread() {
         final Thread self = Thread.currentThread();
         callerLoader = self.getContextClassLoader();
-        failure = null;
         done = false;
         mainExecutor.execute(task);
-        boolean interrupted = false;
-        boolean stallReported = false;
-        final long stallAt = System.nanoTime() + STALL_WARN_NANOS;
-        while (!done) {
-            try {
-                lock.wait(PARK_MILLIS);
-            } catch (InterruptedException e) {
-                interrupted = true;
-            }
-            if (!done && !stallReported && System.nanoTime() - stallAt >= 0L) {
-                stallReported = true;
-                LOGGER.warn("Display message pump has been waiting on the RFB main thread for over {} ms", STALL_WARN_NANOS / 1_000_000L);
-            }
-        }
-        if (interrupted) self.interrupt();
+        await(false);
         final Throwable t = failure;
         if (t != null) {
             throw asUnchecked(t);
         }
     }
 
+    private boolean waiting(boolean presentPump) {
+        return presentPump ? presentPumpPending : !done;
+    }
+
+    private void await(boolean presentPump) {
+        boolean interrupted = false;
+        boolean stallReported = false;
+        final long stallAt = System.nanoTime() + STALL_WARN_NANOS;
+        while (waiting(presentPump)) {
+            try {
+                lock.wait(PARK_MILLIS);
+            } catch (InterruptedException e) {
+                interrupted = true;
+            }
+            if (waiting(presentPump) && !stallReported && System.nanoTime() - stallAt >= 0L) {
+                stallReported = true;
+                LOGGER.warn("Display message pump has been waiting on the RFB main thread for over {} ms", STALL_WARN_NANOS / 1_000_000L);
+            }
+        }
+        if (interrupted) Thread.currentThread().interrupt();
+    }
+
+    public void beginPresent() {
+        synchronized (lock) {
+            presentInFlight = true;
+            presentPumpPending = true;
+            presentLoader = Thread.currentThread().getContextClassLoader();
+        }
+    }
+
+    public void runPresentPump() {
+        final ClassLoader loader;
+        synchronized (lock) {
+            loader = presentLoader;
+        }
+        final Throwable t = pumpWith(loader);
+        synchronized (lock) {
+            if (t != null) presentFailure = t;
+            presentPumpPending = false;
+            lock.notifyAll();
+        }
+    }
+
+    public void endPresent() {
+        synchronized (lock) {
+            presentInFlight = false;
+            presentPumpPending = false;
+            lock.notifyAll();
+        }
+    }
+
     private void runPump() {
+        final Throwable t = pumpWith(callerLoader);
+        synchronized (lock) {
+            failure = t;
+            done = true;
+            lock.notifyAll();
+        }
+    }
+
+    private Throwable pumpWith(ClassLoader loader) {
         final Thread self = Thread.currentThread();
         final ClassLoader saved = self.getContextClassLoader();
         try {
-            self.setContextClassLoader(callerLoader);
+            if (loader != null) self.setContextClassLoader(loader);
             pumpBody.run();
+            return null;
         } catch (Throwable t) {
-            failure = t;
+            return t;
         } finally {
-            try {
-                self.setContextClassLoader(saved);
-            } finally {
-                synchronized (lock) {
-                    done = true;
-                    lock.notifyAll();
-                }
-            }
+            self.setContextClassLoader(saved);
         }
     }
 

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/backend/RenderBackend.java

@@ -1,10 +1,14 @@
 package com.gtnewhorizons.angelica.glsm.backend;
 
 import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
+import com.gtnewhorizons.angelica.glsm.GLESFormatRemap;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.RenderSystem;
+import com.gtnewhorizons.angelica.glsm.texture.TextureStaging;
 import org.lwjgl.LWJGLException;
 import org.lwjgl.opengl.Display;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL12;
 import org.lwjgl.opengl.GL20;
 
 import java.nio.ByteBuffer;
@@ -32,6 +36,9 @@ public abstract class RenderBackend {
     /** Returns true if the current thread has a valid render context. */
     public abstract boolean hasContext();
 
+    /** Returns true if the calling thread may issue render commands. */
+    public boolean hasContextOnThread() { return hasContext(); }
+
     /** Returns true if the calling thread owns the "GL Context" */
     public abstract boolean isCurrent();
 
@@ -66,6 +73,7 @@ public abstract class RenderBackend {
     public abstract void flush();
     public abstract void finish();
 
+    private final ByteBuffer[] clientStagingCache = new ByteBuffer[16];
     private VSyncMode effectiveVSyncMode = VSyncMode.ON;
     private VSyncMode preferredTearFreeMode;
 
@@ -263,9 +271,8 @@ public abstract class RenderBackend {
 
     public String getTransferDebugInfo() { return null; }
 
-    public boolean bindVoxelizationRegion(int ssboBinding, long openPass, float x, float y, float z) { return false; }
     public long beginVoxelizationBatch(int ssboBinding) { return 0L; }
-    public void voxelizeRange(long pass, int vertexOffset, int vertexCount) {}
+    public void voxelizeRegion(long pass, boolean rebindVertexBuffer, float x, float y, float z, int rangeBase, int rangeCount, int vertexTotal) {}
     public void endVoxelizationBatch(long pass) {}
 
     public abstract void enable(int cap);
@@ -351,6 +358,71 @@ public abstract class RenderBackend {
     public void texImage3D(int target, int level, int internalFormat, int width, int height, int depth, int border, int format, int type, IntBuffer pixels) {}
     public void texSubImage1D(int target, int level, int xoffset, int width, int format, int type, ByteBuffer pixels) {}
     public void texSubImage2D(int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, long pboOffset) {}
+
+    public TextureStaging beginTextureStaging(int level, int x, int y, int width, int height) {
+        final int size = Math.multiplyExact(Math.multiplyExact(width, height), 4);
+        ByteBuffer buffer = null;
+        for (int i = 0; i < clientStagingCache.length; i++) {
+            final ByteBuffer cached = clientStagingCache[i];
+            if (cached != null && cached.capacity() == size) {
+                clientStagingCache[i] = null;
+                buffer = cached;
+                break;
+            }
+        }
+        if (buffer == null) buffer = MemoryUtilities.memAlloc(size);
+        buffer.clear();
+        return new ClientTextureStaging(buffer, level, x, y, width, height);
+    }
+
+    public boolean commitTextureStaging(TextureStaging staging) {
+        final int type = RenderSystem.isGLES() ? GLESFormatRemap.remapPixelType(GL12.GL_BGRA, GL12.GL_UNSIGNED_INT_8_8_8_8_REV) : GL12.GL_UNSIGNED_INT_8_8_8_8_REV;
+        try {
+            final ClientTextureStaging s = (ClientTextureStaging) staging;
+            texSubImage2D(GL11.GL_TEXTURE_2D, s.level(), s.x(), s.y(), s.width(), s.height(), GL12.GL_BGRA, type, s.buffer());
+        } finally {
+            recycleClientStaging(staging.buffer());
+        }
+        return true;
+    }
+
+    public void abandonTextureStaging(TextureStaging staging) {
+        recycleClientStaging(staging.buffer());
+    }
+
+    public void trimTextureStaging() {
+        for (int i = 0; i < clientStagingCache.length; i++) {
+            MemoryUtilities.memFree(clientStagingCache[i]);
+            clientStagingCache[i] = null;
+        }
+    }
+
+    private record ClientTextureStaging(ByteBuffer buffer, int level, int x, int y, int width, int height) implements TextureStaging {
+        @Override
+        public boolean bgra() {
+            return true;
+        }
+    }
+
+    private void recycleClientStaging(ByteBuffer buffer) {
+        int victim = -1;
+        for (int i = 0; i < clientStagingCache.length; i++) {
+            final ByteBuffer cached = clientStagingCache[i];
+            if (cached == null) {
+                clientStagingCache[i] = buffer;
+                return;
+            }
+            if (cached.capacity() < buffer.capacity() && (victim < 0 || cached.capacity() < clientStagingCache[victim].capacity())) {
+                victim = i;
+            }
+        }
+        if (victim < 0) {
+            MemoryUtilities.memFree(buffer);
+            return;
+        }
+        MemoryUtilities.memFree(clientStagingCache[victim]);
+        clientStagingCache[victim] = buffer;
+    }
     public void texSubImage3D(int target, int level, int xoffset, int yoffset, int zoffset, int width, int height, int depth, int format, int type, ByteBuffer pixels) {}
     public void copyTexImage1D(int target, int level, int internalFormat, int x, int y, int width, int border) {}
     public void copyTexImage2D(int target, int level, int internalFormat, int x, int y, int width, int height, int border) {}
@@ -435,6 +507,10 @@ public abstract class RenderBackend {
     public abstract int getUniformLocation(int program, ByteBuffer name);
     public boolean isShader(int obj) { return false; }
     public boolean isProgram(int obj) { return false; }
+    public boolean supportsProgramBinary() { return false; }
+    public void programParameteri(int program, int pname, int value) {}
+    public void getProgramBinary(int program, IntBuffer length, IntBuffer binaryFormat, ByteBuffer binary) {}
+    public void programBinary(int program, int binaryFormat, ByteBuffer binary) {}
     public void validateProgram(int program) {}
     public void getAttachedShaders(int program, IntBuffer count, IntBuffer shaders) {
         if (count != null) count.put(0, 0);
@@ -543,12 +619,7 @@ public abstract class RenderBackend {
     public abstract void textureParameteri(int texture, int target, int pname, int param);
     public abstract void textureParameterf(int texture, int target, int pname, float param);
     public abstract void textureParameteriv(int texture, int target, int pname, IntBuffer params);
-    public abstract void texStorage1D(int target, int levels, int internalFormat, int width);
     public abstract void texStorage2D(int target, int levels, int internalFormat, int width, int height);
-    public abstract void texStorage3D(int target, int levels, int internalFormat, int width, int height, int depth);
-    public abstract void textureStorage1D(int texture, int levels, int internalFormat, int width);
-    public abstract void textureStorage2D(int texture, int levels, int internalFormat, int width, int height);
-    public abstract void textureStorage3D(int texture, int levels, int internalFormat, int width, int height, int depth);
     public abstract void generateTextureMipmap(int texture);
     public abstract void textureImage2DEXT(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels);
     public abstract void textureImage2DEXT(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/dsa/DSAARB.java

@@ -1,6 +1,7 @@
 package com.gtnewhorizons.angelica.glsm.dsa;
 
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.texture.TextureInfoCache;
 import org.lwjgl.opengl.GL11;
 
 import java.nio.ByteBuffer;
@@ -73,7 +74,8 @@ public class DSAARB extends DSAUnsupported {
 
     @Override
     public int getTexParameteri(int texture, int target, int pname) {
-        return GLStateManager.getTexParameterOrDefault(texture, pname, () -> RENDER_BACKEND.getTextureParameteri(texture, target, pname));
+        final long v = GLStateManager.lookupTexParameteri(TextureInfoCache.INSTANCE.getInfo(texture), pname);
+        return v != GLStateManager.TEX_PARAM_MISS ? (int) v : RENDER_BACKEND.getTextureParameteri(texture, target, pname);
     }
 
     @Override
@@ -131,26 +133,13 @@ public class DSAARB extends DSAUnsupported {
 
     @Override
     public int createFramebuffer() {
+        GLStateManager.requireContext("glCreateFramebuffers");
         return RENDER_BACKEND.createFramebuffers();
     }
 
     @Override
     public int createTexture(int target) {
+        GLStateManager.requireContext("glCreateTextures");
         return RENDER_BACKEND.createTextures(target);
     }
-
-    @Override
-    public void textureStorage1D(int texture, int target, int levels, int internalFormat, int width) {
-        RENDER_BACKEND.textureStorage1D(texture, levels, internalFormat, width);
-    }
-
-    @Override
-    public void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height) {
-        RENDER_BACKEND.textureStorage2D(texture, levels, internalFormat, width, height);
-    }
-
-    @Override
-    public void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth) {
-        RENDER_BACKEND.textureStorage3D(texture, levels, internalFormat, width, height, depth);
-    }
 }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/dsa/DSAAccess.java

@@ -40,9 +40,4 @@ public interface DSAAccess {
 
     int createFramebuffer();
     int createTexture(int target);
-
-    // Texture storage methods for custom images
-    void textureStorage1D(int texture, int target, int levels, int internalFormat, int width);
-    void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height);
-    void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth);
 }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/dsa/DSAUnsupported.java

@@ -1,6 +1,7 @@
 package com.gtnewhorizons.angelica.glsm.dsa;
 
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.stacks.TextureBindingStack;
 import org.lwjgl.opengl.GL11;
 
 import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
@@ -23,16 +24,15 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, ByteBuffer pixels) {
-        // Get what cache thinks is bound - we'll restore to this to keep cache/GL in sync
-        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        final int cachedBinding = previousBinding(target);
         RENDER_BACKEND.bindTexture(target, texture);
         RENDER_BACKEND.texImage2D(target, level, internalformat, width, height, border, format, type, pixels);
-        RENDER_BACKEND.bindTexture(target, cachedBinding); // Restore to cache value
+        RENDER_BACKEND.bindTexture(target, cachedBinding);
     }
 
     @Override
     public void textureImage2D(int texture, int target, int level, int internalformat, int width, int height, int border, int format, int type, IntBuffer pixels) {
-        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        final int cachedBinding = previousBinding(target);
         RENDER_BACKEND.bindTexture(target, texture);
         RENDER_BACKEND.texImage2D(target, level, internalformat, width, height, border, format, type, pixels);
         RENDER_BACKEND.bindTexture(target, cachedBinding);
@@ -40,7 +40,7 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, ByteBuffer pixels) {
-        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        final int cachedBinding = previousBinding(target);
         RENDER_BACKEND.bindTexture(target, texture);
         RENDER_BACKEND.texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
         RENDER_BACKEND.bindTexture(target, cachedBinding);
@@ -48,7 +48,7 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public void textureSubImage2D(int texture, int target, int level, int xoffset, int yoffset, int width, int height, int format, int type, IntBuffer pixels) {
-        final int cachedBinding = GLStateManager.getBoundTextureForServerState();
+        final int cachedBinding = previousBinding(target);
         RENDER_BACKEND.bindTexture(target, texture);
         RENDER_BACKEND.texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
         RENDER_BACKEND.bindTexture(target, cachedBinding);
@@ -56,20 +56,23 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public void texParameteri(int texture, int target, int pname, int param) {
-        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        final int previous = bindForEdit(target, texture);
         GLStateManager.glTexParameteri(target, pname, param);
+        restoreBinding(target, previous);
     }
 
     @Override
     public void texParameterf(int texture, int target, int pname, float param) {
-        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        final int previous = bindForEdit(target, texture);
         GLStateManager.glTexParameterf(target, pname, param);
+        restoreBinding(target, previous);
     }
 
     @Override
     public void texParameteriv(int texture, int target, int pname, IntBuffer params) {
-        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
+        final int previous = bindForEdit(target, texture);
         GLStateManager.glTexParameter(target, pname, params);
+        restoreBinding(target, previous);
     }
 
     @Override
@@ -86,19 +89,23 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public int getTexParameteri(int texture, int target, int pname) {
-        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
-        return GLStateManager.glGetTexParameteri(target, pname);
+        final int previous = bindForEdit(target, texture);
+        final int result = GLStateManager.glGetTexParameteri(target, pname);
+        restoreBinding(target, previous);
+        return result;
     }
 
     @Override
     public float getTexParameterf(int texture, int target, int pname) {
-        GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
-        return GLStateManager.glGetTexParameterf(target, pname);
+        final int previous = bindForEdit(target, texture);
+        final float result = GLStateManager.glGetTexParameterf(target, pname);
+        restoreBinding(target, previous);
+        return result;
     }
 
     @Override
     public int getTexLevelParameteri(int texture, int level, int pname) {
-        final int previous = GLStateManager.getBoundTextureForServerState();
+        final int previous = previous2D();
         RENDER_BACKEND.bindTexture(GL11.GL_TEXTURE_2D, texture);
         final int result = RENDER_BACKEND.getTexLevelParameteri(GL11.GL_TEXTURE_2D, level, pname);
         RENDER_BACKEND.bindTexture(GL11.GL_TEXTURE_2D, previous);
@@ -107,7 +114,7 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public void copyTexSubImage2D(int destTexture, int target, int i, int i1, int i2, int i3, int i4, int width, int height) {
-        final int previous = GLStateManager.getBoundTextureForServerState();
+        final int previous = previous2D();
         GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, destTexture);
         RENDER_BACKEND.copyTexSubImage2D(target, i, i1, i2, i3, i4, width, height);
         GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, previous);
@@ -158,32 +165,44 @@ public class DSAUnsupported implements DSAAccess {
 
     @Override
     public int createTexture(int target) {
-        final int texture = RENDER_BACKEND.genTextures();
+        final int texture = GLStateManager.glGenTextures();
         GLStateManager.glBindTexture(GL11.GL_TEXTURE_2D, texture);
         return texture;
     }
 
-    @Override
-    public void textureStorage1D(int texture, int target, int levels, int internalFormat, int width) {
-        final int previous = RENDER_BACKEND.getInteger(GL11.GL_TEXTURE_BINDING_1D);
-        RENDER_BACKEND.bindTexture(target, texture);
-        RENDER_BACKEND.texStorage1D(target, levels, internalFormat, width);
-        RENDER_BACKEND.bindTexture(target, previous);
+    private static int bindingQuery(int target) {
+        return switch (target) {
+            case GL11.GL_TEXTURE_1D -> GL11.GL_TEXTURE_BINDING_1D;
+            case GL12.GL_TEXTURE_3D -> GL12.GL_TEXTURE_BINDING_3D;
+            case GL13.GL_TEXTURE_CUBE_MAP -> GL13.GL_TEXTURE_BINDING_CUBE_MAP;
+            case GL30.GL_TEXTURE_2D_ARRAY -> GL30.GL_TEXTURE_BINDING_2D_ARRAY;
+            case GL31.GL_TEXTURE_RECTANGLE -> GL31.GL_TEXTURE_BINDING_RECTANGLE;
+            default -> GL11.GL_TEXTURE_BINDING_2D;
+        };
     }
 
-    @Override
-    public void textureStorage2D(int texture, int target, int levels, int internalFormat, int width, int height) {
-        final int previous = (target == GL11.GL_TEXTURE_2D) ? GLStateManager.getBoundTextureForServerState() : RENDER_BACKEND.getInteger(GL31.GL_TEXTURE_BINDING_RECTANGLE);
-        RENDER_BACKEND.bindTexture(target, texture);
-        RENDER_BACKEND.texStorage2D(target, levels, internalFormat, width, height);
-        RENDER_BACKEND.bindTexture(target, previous);
+    private static int previousBinding(int target) {
+        return target == GL11.GL_TEXTURE_2D ? previous2D() : RENDER_BACKEND.getInteger(bindingQuery(target));
     }
 
-    @Override
-    public void textureStorage3D(int texture, int target, int levels, int internalFormat, int width, int height, int depth) {
-        final int previous = RENDER_BACKEND.getInteger(GL12.GL_TEXTURE_BINDING_3D);
-        RENDER_BACKEND.bindTexture(target, texture);
-        RENDER_BACKEND.texStorage3D(target, levels, internalFormat, width, height, depth);
-        RENDER_BACKEND.bindTexture(target, previous);
+    private static int previous2D() {
+        if (GLStateManager.isCachingEnabled()) {
+            final TextureBindingStack slot = GLStateManager.getTextures().getTextureUnitBindings(GLStateManager.getActiveTextureUnit());
+            final int t = slot.getTarget();
+            if (t == 0 || t == GL11.GL_TEXTURE_2D) return slot.getBinding();
+        }
+        return RENDER_BACKEND.getInteger(GL11.GL_TEXTURE_BINDING_2D);
+    }
+
+    private static int bindForEdit(int target, int texture) {
+        final int previous = previousBinding(target);
+        if (target == GL11.GL_TEXTURE_2D) GLStateManager.glBindTexture(target, texture);
+        else RENDER_BACKEND.bindTexture(target, texture);
+        return previous;
+    }
+
+    private static void restoreBinding(int target, int previous) {
+        if (target == GL11.GL_TEXTURE_2D) GLStateManager.glBindTexture(target, previous);
+        else RENDER_BACKEND.bindTexture(target, previous);
     }
 }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/ffp/GeometryShaderGenerator.java

@@ -54,9 +54,17 @@ public final class GeometryShaderGenerator {
         sb.append("    vec4 c0 = gl_in[0].gl_Position;\n");
         sb.append("    vec4 c1 = gl_in[1].gl_Position;\n\n");
 
+        sb.append("    float d0 = c0.z + c0.w;\n");
+        sb.append("    float d1 = c1.z + c1.w;\n");
+        sb.append("    if (d0 < 0.0 && d1 < 0.0) return;\n");
+        sb.append("    float t0 = d0 < 0.0 ? d0 / (d0 - d1) : 0.0;\n");
+        sb.append("    float t1 = d1 < 0.0 ? d0 / (d0 - d1) : 1.0;\n");
+        sb.append("    vec4 p0 = mix(c0, c1, t0);\n");
+        sb.append("    vec4 p1 = mix(c0, c1, t1);\n\n");
+
         sb.append("    // NDC positions\n");
-        sb.append("    vec2 n0 = c0.xy / c0.w;\n");
-        sb.append("    vec2 n1 = c1.xy / c1.w;\n\n");
+        sb.append("    vec2 n0 = p0.xy / p0.w;\n");
+        sb.append("    vec2 n1 = p1.xy / p1.w;\n\n");
 
         sb.append("    // Screen-space direction and perpendicular\n");
         sb.append("    vec2 dir = normalize((n1 - n0) * u_ViewportSize);\n");
@@ -74,22 +82,22 @@ public final class GeometryShaderGenerator {
     }
 
     private static void emitVertex(StringBuilder sb, VertexKey key, int endpointIdx, String offsetExpr) {
-        final String ci = "c" + endpointIdx;
+        final String pi = "p" + endpointIdx;
         final String ni = "n" + endpointIdx;
-        final String idx = "[" + endpointIdx + "]";
+        final String ti = "t" + endpointIdx;
 
         sb.append("    // Endpoint ").append(endpointIdx).append(' ').append(offsetExpr).append('\n');
 
-        sb.append("    v_Color = v_Color_gs").append(idx).append(";\n");
+        sb.append("    v_Color = ").append(lerp("v_Color_gs", ti)).append(";\n");
         if (key.separateSpecular()) {
-            sb.append("    v_SpecularColor = v_SpecularColor_gs").append(idx).append(";\n");
+            sb.append("    v_SpecularColor = ").append(lerp("v_SpecularColor_gs", ti)).append(";\n");
         }
-        if (key.unitTexCoordEnabled(0) || key.texGenEnabled()) sb.append("    v_TexCoord0 = v_TexCoord0_gs").append(idx).append(";\n");
-        if (key.lightmapEnabled())            sb.append("    v_TexCoord1 = v_TexCoord1_gs").append(idx).append(";\n");
-        if (key.unitTexCoordEnabled(2))       sb.append("    v_TexCoord2 = v_TexCoord2_gs").append(idx).append(";\n");
-        if (key.unitTexCoordEnabled(3))       sb.append("    v_TexCoord3 = v_TexCoord3_gs").append(idx).append(";\n");
+        if (key.unitTexCoordEnabled(0) || key.texGenEnabled()) sb.append("    v_TexCoord0 = ").append(lerp("v_TexCoord0_gs", ti)).append(";\n");
+        if (key.lightmapEnabled())            sb.append("    v_TexCoord1 = ").append(lerp("v_TexCoord1_gs", ti)).append(";\n");
+        if (key.unitTexCoordEnabled(2))       sb.append("    v_TexCoord2 = ").append(lerp("v_TexCoord2_gs", ti)).append(";\n");
+        if (key.unitTexCoordEnabled(3))       sb.append("    v_TexCoord3 = ").append(lerp("v_TexCoord3_gs", ti)).append(";\n");
         if (key.fogEnabled()) {
-            sb.append("    v_FogCoord = v_FogCoord_gs").append(idx).append(";\n");
+            sb.append("    v_FogCoord = ").append(lerp("v_FogCoord_gs", ti)).append(";\n");
         }
         if (key.lineStipple()) {
             sb.append("    v_LineStart = v_LineStart_gs[0];\n");
@@ -97,11 +105,15 @@ public final class GeometryShaderGenerator {
 
         if (key.clipPlanesEnabled()) {
             for (int i = 0; i < 8; i++) {
-                sb.append("    gl_ClipDistance[").append(i).append("] = gl_in").append(idx).append(".gl_ClipDistance[").append(i).append("];\n");
+                sb.append("    gl_ClipDistance[").append(i).append("] = mix(gl_in[0].gl_ClipDistance[").append(i).append("], gl_in[1].gl_ClipDistance[").append(i).append("], ").append(ti).append(");\n");
             }
         }
 
-        sb.append("    gl_Position = vec4((").append(ni).append(' ').append(offsetExpr).append(") * ").append(ci).append(".w, ").append(ci).append(".z, ").append(ci).append(".w);\n");
+        sb.append("    gl_Position = vec4((").append(ni).append(' ').append(offsetExpr).append(") * ").append(pi).append(".w, ").append(pi).append(".z, ").append(pi).append(".w);\n");
         sb.append("    EmitVertex();\n\n");
     }
+
+    private static String lerp(String input, String t) {
+        return "mix(" + input + "[0], " + input + "[1], " + t + ")";
+    }
 }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/GLSMConfig.java

@@ -18,6 +18,7 @@ public final class GLSMConfig {
 
     public static boolean extendedAttribsExpected;
     public static volatile boolean expandVertexFormats;
+    public static int workerThreadCount;
 
     private GLSMConfig() {}
 }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/GLSMHooks.java

@@ -11,10 +11,10 @@ public final class GLSMHooks {
     public static DeferredDepthColorHandler depthColorHandler;
     public static GlintColorHandler glintColorHandler;
     public static ImmediateExtendedAttribHandler immediateExtendedHandler;
-    public static ShaderWorkSubmitter shaderWorkSubmitter;
     public static ShaderTransformPostProcessor postTransformProcessor;
     public static PerFrameUniformBlock perFrameUniformBlock;
     public static PerFrameUniformBlock perPassUniformBlock;
+    public static Runnable uniformBlockBarrier;
     public static PendingProgramSelection pendingProgramSelection;
 
     public static void resolvePendingProgram() {

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/ImmediateExtendedAttribHandler.java

@@ -21,6 +21,10 @@ public interface ImmediateExtendedAttribHandler {
 
     boolean wantsExtendedCapture();
 
+    boolean wantsFaceNormals();
+
+    void writeFaceNormals(int[] rawBuffer, int vertexCount);
+
     void build(int[] rawBuffer, int vertexCount, int vertsPerPrim, int normalIntIndex, long dstAddr, int dstStride);
 
     void buildPacked(long srcBase, int stride, int posOffset, int texOffset, int normalOffset,

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/ShaderWorkSubmitter.java

@@ -1,8 +0,0 @@
-package com.gtnewhorizons.angelica.glsm.hooks;
-
-import java.util.concurrent.CompletableFuture;
-import java.util.function.Supplier;
-
-public interface ShaderWorkSubmitter {
-    <T> CompletableFuture<T> submit(Supplier<T> work);
-}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/hooks/TextureUtilHooks.java

@@ -1,14 +1,28 @@
 package com.gtnewhorizons.angelica.glsm.hooks;
 
 import com.gtnewhorizons.angelica.glsm.DisplayListManager;
+import com.gtnewhorizons.angelica.glsm.GLContextState;
 import com.gtnewhorizons.angelica.glsm.GLStateManager;
 import com.gtnewhorizons.angelica.glsm.RenderSystem;
+import com.gtnewhorizons.angelica.glsm.backend.BackendManager;
+import com.gtnewhorizons.angelica.glsm.texture.TextureInfo;
+import com.gtnewhorizons.angelica.glsm.texture.TextureInfoCache;
 import org.lwjgl.opengl.EXTTextureFilterAnisotropic;
 import org.lwjgl.opengl.GL11;
 import org.lwjgl.opengl.GL12;
 
 public final class TextureUtilHooks {
 
+    private static int pausedTexture;
+    private static int pausedMin;
+    private static int pausedMag;
+    private static float pausedAniso;
+
+    private static int nearestTexture;
+    private static int nearestMin;
+    private static int nearestMag;
+    private static float nearestAniso;
+
     private TextureUtilHooks() {}
 
     public static void setMaxLevel(int mipmapLevels) {
@@ -16,7 +30,17 @@ public final class TextureUtilHooks {
     }
 
     public static void captureBoundFilterTexture() {
-        GLStateManager.ctx().savedFilterTextureId = GLStateManager.getBoundTextureForServerState();
+        final GLContextState ctx = GLStateManager.ctx();
+        final int id = GLStateManager.getBoundTextureForServerState();
+        ctx.savedFilterTextureId = id;
+        final TextureInfo info = TextureInfoCache.INSTANCE.getInfo(id);
+        if (info != null) {
+            ctx.savedFilterMin = info.getMinFilter();
+            ctx.savedFilterMag = info.getMagFilter();
+            ctx.savedFilterAniso = info.getMaxAnisotropy();
+        } else {
+            ctx.savedFilterMin = -1;
+        }
     }
 
     public static void clearSavedFilterTexture() {
@@ -42,4 +66,61 @@ public final class TextureUtilHooks {
             GLStateManager.glTexParameterf(GL11.GL_TEXTURE_2D, EXTTextureFilterAnisotropic.GL_TEXTURE_MAX_ANISOTROPY_EXT, aniso);
         }
     }
+
+    public static boolean pauseTemporaryFilter() {
+        final GLContextState ctx = GLStateManager.ctx();
+        final int id = ctx.savedFilterTextureId;
+        if (id == 0 || pausedTexture != 0 || ctx.savedFilterMin < 0
+            || DisplayListManager.getRecordMode() != DisplayListManager.RecordMode.NONE) return false;
+        final TextureInfo info = TextureInfoCache.INSTANCE.getInfo(id);
+        if (info == null) return false;
+        pausedTexture = id;
+        pausedMin = info.getMinFilter();
+        pausedMag = info.getMagFilter();
+        pausedAniso = info.getMaxAnisotropy();
+        setFilter(id, ctx.savedFilterMin, ctx.savedFilterMag, ctx.savedFilterAniso);
+        return true;
+    }
+
+    public static void resumeTemporaryFilter() {
+        if (pausedTexture == 0) return;
+        final int id = pausedTexture;
+        pausedTexture = 0;
+        setFilter(id, pausedMin, pausedMag, pausedAniso);
+    }
+
+    /** TextureUtil.func_152777_a(false, false, 1) without using vanilla's single save slot, which the caller may hold. */
+    public static void forceNearestFilter() {
+        final int id = GLStateManager.getBoundTextureForServerState();
+        final TextureInfo info = id != 0 ? TextureInfoCache.INSTANCE.getInfo(id) : null;
+        if (info == null) {
+            nearestTexture = 0;
+            return;
+        }
+        nearestTexture = id;
+        nearestMin = info.getMinFilter();
+        nearestMag = info.getMagFilter();
+        nearestAniso = info.getMaxAnisotropy();
+        setFilter(id, GL11.GL_NEAREST, GL11.GL_NEAREST, 1.0f);
+    }
+
+    public static void restoreFilterAfterNearest() {
+        if (nearestTexture == 0) return;
+        final int id = nearestTexture;
+        nearestTexture = 0;
+        setFilter(id, nearestMin, nearestMag, nearestAniso);
+    }
+
+    private static void setFilter(int id, int min, int mag, float aniso) {
+        final boolean anisotropic = BackendManager.RENDER_BACKEND.isAnisotropicSupported();
+        if (DisplayListManager.getRecordMode() == DisplayListManager.RecordMode.NONE) {
+            RenderSystem.texParameteri(id, GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, min);
+            RenderSystem.texParameteri(id, GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, mag);
+            if (anisotropic) RenderSystem.texParameterf(id, GL11.GL_TEXTURE_2D, EXTTextureFilterAnisotropic.GL_TEXTURE_MAX_ANISOTROPY_EXT, aniso);
+        } else {
+            GLStateManager.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, min);
+            GLStateManager.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, mag);
+            if (anisotropic) GLStateManager.glTexParameterf(GL11.GL_TEXTURE_2D, EXTTextureFilterAnisotropic.GL_TEXTURE_MAX_ANISOTROPY_EXT, aniso);
+        }
+    }
 }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/loading/ModRedirector.java

@@ -38,6 +38,10 @@ public class ModRedirector {
         return allExclusions;
     }
 
+    public String[] getConstantPoolSearchStrings() {
+        return core.getConstantPoolSearchStrings();
+    }
+
     public boolean shouldTransform(byte[] basicClass) {
         return core.shouldTransform(basicClass);
     }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/loading/RfbModRedirector.java

@@ -1,5 +1,7 @@
 package com.gtnewhorizons.angelica.glsm.loading;
 
+import com.gtnewhorizons.retrofuturabootstrap.api.BytePatternMatcher;
+import com.gtnewhorizons.retrofuturabootstrap.api.ClassHeaderMetadata;
 import com.gtnewhorizons.retrofuturabootstrap.api.ClassNodeHandle;
 import com.gtnewhorizons.retrofuturabootstrap.api.ExtensibleClassLoader;
 import com.gtnewhorizons.retrofuturabootstrap.api.RfbClassTransformer;
@@ -16,10 +18,12 @@ public abstract class RfbModRedirector implements RfbClassTransformer {
 
     private final String id;
     private final ModRedirector inner;
+    private final BytePatternMatcher cstPoolMatcher;
 
     protected RfbModRedirector(@Pattern("[a-z0-9-]+") String id, ModRedirector inner) {
         this.id = id;
         this.inner = inner;
+        this.cstPoolMatcher = new BytePatternMatcher(inner.getConstantPoolSearchStrings(), BytePatternMatcher.Mode.StartsWith);
     }
 
     @Override
@@ -53,7 +57,11 @@ public abstract class RfbModRedirector implements RfbClassTransformer {
         if (!classNode.isPresent()) {
             return false;
         }
-        return inner.shouldTransform(classNode.getOriginalBytes());
+        final ClassHeaderMetadata metadata = classNode.getOriginalMetadata();
+        if (metadata == null) {
+            return inner.shouldTransform(classNode.getOriginalBytes());
+        }
+        return metadata.matchesBytes(classNode.getOriginalBytes(), cstPoolMatcher);
     }
 
     @Override

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/profiling/DebugCounters.java

@@ -0,0 +1,12 @@
+package com.gtnewhorizons.angelica.glsm.profiling;
+
+import java.util.concurrent.atomic.LongAdder;
+
+public final class DebugCounters {
+    public static final LongAdder FENCE_WAIT_NANOS = new LongAdder();
+    public static final LongAdder TRANSFER_WAIT_NANOS = new LongAdder();
+    public static final LongAdder PRESENTS = new LongAdder();
+    public static final LongAdder EMPTY_ACQUIRES = new LongAdder();
+
+    private DebugCounters() {}
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/redirect/GLSMRedirector.java

@@ -176,6 +176,7 @@ public class GLSMRedirector {
     private static final Map<Integer, String> glCapRedirects = new HashMap<>();
     private static final Map<String, String> typeRedirects = new HashMap<>();
     private static final ClassConstantPoolParser cstPoolParser;
+    private static final String[] CONSTANT_POOL_SEARCH_STRINGS;
 
     private static final String[] CORE_EXCLUSIONS = {
         "org.lwjgl",
@@ -826,13 +827,18 @@ public class GLSMRedirector {
         stringsToSearch.add(Display);
         stringsToSearch.addAll(typeRedirects.keySet());
         stringsToSearch.addAll(methodRedirects.keySet());
-        cstPoolParser = new ClassConstantPoolParser(stringsToSearch.toArray(new String[0]));
+        CONSTANT_POOL_SEARCH_STRINGS = stringsToSearch.toArray(new String[0]);
+        cstPoolParser = new ClassConstantPoolParser(CONSTANT_POOL_SEARCH_STRINGS);
     }
 
     public String[] getCoreExclusions() {
         return CORE_EXCLUSIONS.clone();
     }
 
+    public String[] getConstantPoolSearchStrings() {
+        return CONSTANT_POOL_SEARCH_STRINGS.clone();
+    }
+
     public static String getGLPrefix() { return GL_PREFIX; }
 
     public static String getTargetClassName() { return GLStateManager; }

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/shader/GlslVulkanPreprocess.java

@@ -28,6 +28,15 @@ public final class GlslVulkanPreprocess {
 
     public static final String SAMPLER_RENAMED = "angelica_sampler_renamed";
 
+    public static final String RESERVED_RENAMED_PREFIX = "angelica_renamed_";
+
+    private static final Set<String> TARGET_RESERVED = Set.of(
+        "try", "catch", "throw", "delete", "operator", "private", "protected", "friend", "virtual", "explicit",
+        "mutable", "typename", "typeid", "register", "signed", "char", "auto", "nullptr", "constexpr", "decltype",
+        "noexcept", "alignas", "alignof", "static_assert", "thread_local", "wchar_t", "char16_t", "char32_t",
+        "const_cast", "dynamic_cast", "reinterpret_cast", "static_cast", "export",
+        "and", "or", "xor", "bitand", "bitor", "compl", "and_eq", "or_eq", "xor_eq", "not_eq");
+
     public static final String SAMPLERLESS_EXTENSION = "#extension GL_EXT_samplerless_texture_functions : require";
 
     private static final int MAX_VS_INPUT_LOCATIONS = 16;
@@ -211,7 +220,9 @@ public final class GlslVulkanPreprocess {
                     case "sampler" -> edits.add(new Edit(tok.getStartIndex(), tok.getStopIndex(), SAMPLER_RENAMED));
                     case "gl_VertexID" -> edits.add(new Edit(tok.getStartIndex(), tok.getStopIndex(), "gl_VertexIndex"));
                     case "gl_InstanceID" -> edits.add(new Edit(tok.getStartIndex(), tok.getStopIndex(), "gl_InstanceIndex"));
-                    default -> {}
+                    default -> {
+                        if (TARGET_RESERVED.contains(text)) edits.add(new Edit(tok.getStartIndex(), tok.getStopIndex(), RESERVED_RENAMED_PREFIX + text));
+                    }
                 }
             }
         }, root);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/shader/ProgramBinaryCache.java

@@ -0,0 +1,236 @@
+package com.gtnewhorizons.angelica.glsm.shader;
+
+import com.gtnewhorizon.gtnhlib.bytebuf.MemoryUtilities;
+import com.gtnewhorizons.angelica.glsm.GLStateManager;
+import com.gtnewhorizons.angelica.glsm.RenderSystem;
+import com.gtnewhorizons.angelica.glsm.ffp.ShaderManager;
+import com.gtnewhorizons.angelica.glsm.threading.AngelicaWorkers;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.jetbrains.annotations.Nullable;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL20;
+import org.lwjgl.opengl.GL41;
+
+import java.nio.ByteBuffer;
+import java.nio.IntBuffer;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static com.gtnewhorizons.angelica.glsm.backend.BackendManager.RENDER_BACKEND;
+
+/**
+ * Saves linked GL programs to disk and loads them back with glProgramBinary, skipping compile and link.
+ */
+public final class ProgramBinaryCache {
+    private static final Logger LOGGER = LogManager.getLogger("ProgramBinaryCache");
+    static final String LAYER = "gl-program";
+    private static final int PACKS_KEPT = 3;
+
+    private static volatile boolean enabled;
+    private static volatile String packLayer;
+    private static String driverId;
+    private static String fullCompileLayer;
+    private static Set<String> keysInUse;
+    private static List<CompletableFuture<Boolean>> fullCompileWrites;
+    private static Object fullCompileGeneration;
+    private static final AtomicBoolean rejectWarned = new AtomicBoolean();
+    private static final Object WRITE_LOCK = new Object();
+    private static final Map<String, Object> compileGenerations = new HashMap<>();
+    private static int deleteCount;
+
+    private ProgramBinaryCache() {}
+
+    public static void setEnabled(boolean value) {
+        enabled = value;
+    }
+
+    public static boolean isEnabled() {
+        return enabled && packLayer != null && RenderSystem.supportsProgramBinary() && ShaderDiskCache.isEnabled();
+    }
+
+    public static void usePack(String packName) {
+        if (packName == null) {
+            packLayer = null;
+            return;
+        }
+        final String layer = LAYER + '/' + folderName(packName);
+        packLayer = layer;
+        if (!enabled) return;
+        ShaderDiskCache.touchLayer(layer);
+        AngelicaWorkers.run(() -> ShaderDiskCache.keepNewestSubLayers(LAYER, PACKS_KEPT));
+    }
+
+    public static Key key() {
+        return new Key(ShaderDiskCache.key(packLayer).str(driverId()).b(ShaderManager.isEnabled()));
+    }
+
+    public static void markRetrievable(int program) {
+        GLStateManager.glProgramParameteri(program, GL41.GL_PROGRAM_BINARY_RETRIEVABLE_HINT, GL11.GL_TRUE);
+    }
+
+    public static int load(Key key) {
+        final ShaderDiskCache.Key diskKey = key.diskKey;
+        final ShaderDiskCache.Blob blob = ShaderDiskCache.getBlob(diskKey);
+        if (blob == null) return 0;
+        final int format;
+        try {
+            format = Integer.parseInt(blob.tag());
+        } catch (NumberFormatException e) {
+            ShaderDiskCache.remove(diskKey);
+            return 0;
+        }
+        final int program = GLStateManager.glCreateProgram();
+        final ByteBuffer data = MemoryUtilities.memAlloc(blob.data().length);
+        try {
+            data.put(blob.data()).flip();
+            GLStateManager.glProgramBinary(program, format, data);
+        } finally {
+            MemoryUtilities.memFree(data);
+        }
+        if (GLStateManager.glGetProgrami(program, GL20.GL_LINK_STATUS) != GL11.GL_TRUE) {
+            GLStateManager.glDeleteProgram(program);
+            ShaderDiskCache.remove(diskKey);
+            if (rejectWarned.compareAndSet(false, true)) LOGGER.error("Driver rejected a saved shader program!! Recompiling rejected programs from source");
+            return 0;
+        }
+        keep(diskKey);
+        return program;
+    }
+
+    public static void save(Key key, int program) {
+        final int length = GLStateManager.glGetProgrami(program, GL41.GL_PROGRAM_BINARY_LENGTH);
+        if (length <= 0) return;
+        final ByteBuffer data = MemoryUtilities.memAlloc(length);
+        final IntBuffer written = MemoryUtilities.memAllocInt(1);
+        final IntBuffer format = MemoryUtilities.memAllocInt(1);
+        try {
+            GLStateManager.glGetProgramBinary(program, written, format, data);
+            if (written.get(0) <= 0) return;
+            data.limit(written.get(0));
+            final byte[] binary = ShaderCacheIO.toHeap(data);
+            final String formatTag = Integer.toString(format.get(0));
+            final ShaderDiskCache.Key diskKey = key.diskKey;
+            keep(diskKey);
+            final int deletesBefore;
+            synchronized (WRITE_LOCK) {
+                deletesBefore = deleteCount;
+            }
+            final CompletableFuture<Boolean> write = AngelicaWorkers.submit(() -> {
+                synchronized (WRITE_LOCK) {
+                    return deletesBefore == deleteCount && ShaderDiskCache.putBlob(diskKey, formatTag, binary);
+                }
+            });
+            final List<CompletableFuture<Boolean>> writes = fullCompileWrites;
+            if (writes != null) writes.add(write);
+        } finally {
+            MemoryUtilities.memFree(data);
+            MemoryUtilities.memFree(written);
+            MemoryUtilities.memFree(format);
+        }
+    }
+
+    public static void beginFullCompile() {
+        fullCompileLayer = packLayer;
+        keysInUse = new HashSet<>();
+        fullCompileWrites = new ArrayList<>();
+        synchronized (WRITE_LOCK) {
+            fullCompileGeneration = new Object();
+            if (fullCompileLayer != null) compileGenerations.put(fullCompileLayer, fullCompileGeneration);
+        }
+    }
+    public static void finishFullCompile(@Nullable String completedSettings) {
+        final String layer = fullCompileLayer;
+        final Set<String> used = keysInUse;
+        final List<CompletableFuture<Boolean>> writes = fullCompileWrites;
+        final Object generation = fullCompileGeneration;
+        fullCompileLayer = null;
+        keysInUse = null;
+        fullCompileWrites = null;
+        fullCompileGeneration = null;
+        if (layer == null || used == null || writes == null) return;
+
+        final ShaderDiskCache.Key marker = completedSettings != null ? compiledSettingsKey(layer, completedSettings) : null;
+        final String markerHex = marker != null ? marker.hex() : null;
+        CompletableFuture.allOf(writes.toArray(new CompletableFuture<?>[0])).whenComplete((ignored, failure) -> {
+            synchronized (WRITE_LOCK) {
+                if (compileGenerations.get(layer) != generation) return;
+                if (marker == null || failure != null) return;
+                for (CompletableFuture<Boolean> write : writes) {
+                    if (!write.join()) return;
+                }
+                ShaderDiskCache.retainLayer(layer, used);
+                ShaderDiskCache.retainLayer(layer + "/settings", Collections.singleton(markerHex));
+                ShaderDiskCache.putString(marker, "");
+            }
+        });
+    }
+
+    public static void deleteAll() {
+        synchronized (WRITE_LOCK) {
+            deleteCount++;
+            compileGenerations.clear();
+            ShaderDiskCache.deleteLayer(LAYER);
+        }
+    }
+
+    public static boolean wasCompiledFor(String settings) {
+        final String layer = packLayer;
+        return layer != null && ShaderDiskCache.getString(compiledSettingsKey(layer, settings)) != null;
+    }
+
+    private static ShaderDiskCache.Key compiledSettingsKey(String layer, String settings) {
+        return ShaderDiskCache.key(layer + "/settings").str(driverId()).b(ShaderManager.isEnabled()).str(settings);
+    }
+
+    private static String folderName(String packName) {
+        final StringBuilder name = new StringBuilder(Math.min(packName.length(), 64));
+        for (int i = 0; i < packName.length() && name.length() < 64; i++) {
+            final char c = packName.charAt(i);
+            name.append(c < 128 && (Character.isLetterOrDigit(c) || c == '.' || c == '-' || c == '_') ? c : '_');
+        }
+        return name.toString();
+    }
+
+    private static void keep(ShaderDiskCache.Key diskKey) {
+        final String hex = diskKey.hex();
+        final Set<String> used = keysInUse;
+        if (used != null) used.add(hex);
+    }
+
+    private static String driverId() {
+        String id = driverId;
+        if (id == null) {
+            id = RENDER_BACKEND.getString(GL11.GL_VENDOR) + '|' + RENDER_BACKEND.getString(GL11.GL_RENDERER) + '|'
+                + RENDER_BACKEND.getString(GL11.GL_VERSION) + '|' + RENDER_BACKEND.getString(GL20.GL_SHADING_LANGUAGE_VERSION) + '|'
+                + RenderSystem.isGLES() + '|' + RENDER_BACKEND.getMinGLSLVersion();
+            driverId = id;
+        }
+        return id;
+    }
+
+    public static final class Key {
+        private final ShaderDiskCache.Key diskKey;
+
+        private Key(ShaderDiskCache.Key diskKey) {
+            this.diskKey = diskKey;
+        }
+
+        public Key stage(int shaderType, String source) {
+            diskKey.str("stage").i(shaderType).str(source);
+            return this;
+        }
+
+        public Key attribute(String name, int index) {
+            diskKey.str("attribute").str(name).i(index);
+            return this;
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/shader/ShaderCacheIO.java

@@ -0,0 +1,106 @@
+package com.gtnewhorizons.angelica.glsm.shader;
+
+import it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenHashMap;
+import me.eigenraven.lwjgl3ify.api.Lwjgl3Aware;
+import org.lwjgl.Version;
+import org.lwjgl.system.MemoryUtil;
+import org.lwjgl.system.SharedLibrary;
+
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Set;
+import java.util.TreeSet;
+
+@Lwjgl3Aware
+public final class ShaderCacheIO {
+
+    private ShaderCacheIO() {}
+
+    public static byte[] toHeap(ByteBuffer buf) {
+        final byte[] heap = new byte[buf.remaining()];
+        buf.duplicate().get(heap);
+        return heap;
+    }
+
+    public static ByteBuffer toNative(byte[] data) {
+        final ByteBuffer buf = MemoryUtil.memAlloc(data.length);
+        buf.put(data).flip();
+        return buf;
+    }
+
+    public static <K, V> void lruPut(Object2ObjectLinkedOpenHashMap<K, V> map, K key, V value, int max) {
+        synchronized (map) {
+            map.putAndMoveToFirst(key, value);
+            while (map.size() > max) map.removeLast();
+        }
+    }
+
+    public static void writeStr(DataOutputStream out, String s) throws IOException {
+        if (s == null) {
+            out.writeInt(-1);
+            return;
+        }
+        final byte[] utf8 = s.getBytes(StandardCharsets.UTF_8);
+        out.writeInt(utf8.length);
+        out.write(utf8);
+    }
+
+    public static String readStr(ByteBuffer in) {
+        final int n = in.getInt();
+        if (n == -1) return null;
+        final int pos = in.position();
+        in.position(pos + n);
+        return new String(in.array(), in.arrayOffset() + pos, n, StandardCharsets.UTF_8);
+    }
+
+    public static int readCount(ByteBuffer in) {
+        final int n = in.getInt();
+        if (n < 0 || n > in.remaining()) throw new BufferUnderflowException();
+        return n;
+    }
+
+    public static void writeBytes(DataOutputStream out, byte[] data) throws IOException {
+        out.writeInt(data.length);
+        out.write(data);
+    }
+
+    public static byte[] readBytes(ByteBuffer in) {
+        final byte[] out = new byte[readCount(in)];
+        in.get(out);
+        return out;
+    }
+
+    public static void writeInts(DataOutputStream out, int[] values) throws IOException {
+        out.writeInt(values.length);
+        for (int v : values) out.writeInt(v);
+    }
+
+    public static int[] readInts(ByteBuffer in) {
+        final int n = readCount(in);
+        final int[] out = new int[n];
+        for (int i = 0; i < n; i++) out[i] = in.getInt();
+        return out;
+    }
+
+    public static void writeSortedStrs(DataOutputStream out, Set<String> values) throws IOException {
+        final Set<String> sorted = values == null ? Set.of() : new TreeSet<>(values);
+        out.writeInt(sorted.size());
+        for (String s : sorted) writeStr(out, s);
+    }
+
+    public static Set<String> readStrSet(ByteBuffer in) {
+        final String[] out = new String[readCount(in)];
+        for (int i = 0; i < out.length; i++) out[i] = readStr(in);
+        return Set.copyOf(Arrays.asList(out));
+    }
+
+    public static String libraryId(SharedLibrary lib) {
+        final String path = lib.getPath();
+        return Version.getVersion() + '|' + lib.getName() + '|' + (path == null ? -1 : new File(path).length());
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/shader/ShaderDiskCache.java

@@ -0,0 +1,403 @@
+package com.gtnewhorizons.angelica.glsm.shader;
+
+import com.gtnewhorizons.angelica.glsm.threading.AngelicaWorkers;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataOutputStream;
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.StandardOpenOption;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.nio.file.attribute.FileTime;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.stream.Stream;
+import java.util.zip.CRC32;
+
+import static com.gtnewhorizons.angelica.glsm.shader.ShaderCacheIO.readBytes;
+import static com.gtnewhorizons.angelica.glsm.shader.ShaderCacheIO.readCount;
+import static com.gtnewhorizons.angelica.glsm.shader.ShaderCacheIO.readStr;
+import static com.gtnewhorizons.angelica.glsm.shader.ShaderCacheIO.writeBytes;
+import static com.gtnewhorizons.angelica.glsm.shader.ShaderCacheIO.writeStr;
+
+public final class ShaderDiskCache {
+    private static final Logger LOGGER = LogManager.getLogger("ShaderDiskCache");
+    private static final int MAGIC = 0x41534331;
+    private static final int HEADER_BYTES = 12;
+    static final long MAX_BYTES = 256L << 20;
+    private static volatile Path root;
+    private static final AtomicBoolean writeWarned = new AtomicBoolean();
+    private static final AtomicInteger TMP_SEQ = new AtomicInteger();
+
+    private ShaderDiskCache() {}
+
+    public static void configure(Path dir, String salt) {
+        try {
+            Files.createDirectories(dir);
+            final Path saltFile = dir.resolve("salt");
+            final String existing = Files.isRegularFile(saltFile) ? new String(Files.readAllBytes(saltFile), StandardCharsets.UTF_8) : null;
+            if (!salt.equals(existing)) {
+                wipe(dir);
+                Files.write(saltFile, salt.getBytes(StandardCharsets.UTF_8));
+            }
+            root = dir;
+            AngelicaWorkers.run(() -> enforceCap(dir, MAX_BYTES));
+            LOGGER.info("Shader disk cache at {}", dir);
+        } catch (IOException | RuntimeException e) {
+            root = null;
+            LOGGER.warn("Shader disk cache disabled", e);
+        }
+    }
+
+    public static boolean isEnabled() {
+        return root != null;
+    }
+
+    public static Key key(String layer) {
+        return new Key(layer);
+    }
+
+    public static byte[] get(Key key) {
+        final Path r = root;
+        if (r == null) return null;
+        final Path file = key.path(r);
+        final byte[] payload;
+        try (FileChannel ch = FileChannel.open(file, StandardOpenOption.READ)) {
+            payload = read(ch);
+        } catch (IOException e) {
+            return null;
+        }
+        if (payload == null) {
+            try {
+                Files.deleteIfExists(file);
+            } catch (IOException ignored) {}
+        }
+        return payload;
+    }
+
+    private static byte[] read(FileChannel ch) throws IOException {
+        final long size = ch.size();
+        if (size < HEADER_BYTES || size - HEADER_BYTES > Integer.MAX_VALUE) return null;
+        final ByteBuffer header = ByteBuffer.allocate(HEADER_BYTES);
+        readFully(ch, header);
+        header.flip();
+        if (header.getInt() != MAGIC) return null;
+        final int length = header.getInt();
+        final int crc = header.getInt();
+        if (length != size - HEADER_BYTES) return null;
+        final byte[] payload = new byte[length];
+        readFully(ch, ByteBuffer.wrap(payload));
+        final CRC32 c = new CRC32();
+        c.update(payload, 0, length);
+        return (int) c.getValue() == crc ? payload : null;
+    }
+
+    private static void readFully(FileChannel ch, ByteBuffer buf) throws IOException {
+        while (buf.hasRemaining()) {
+            if (ch.read(buf) < 0) throw new EOFException();
+        }
+    }
+
+    public static boolean put(Key key, byte[] payload) {
+        final Path r = root;
+        if (r == null) return false;
+        final Path target = key.path(r);
+        final Path tmp = target.resolveSibling(key.hex() + '.' + TMP_SEQ.getAndIncrement() + ".tmp");
+        try {
+            try {
+                write(tmp, payload);
+            } catch (IOException e) {
+                Files.createDirectories(target.getParent());
+                write(tmp, payload);
+            }
+            Files.move(tmp, target, StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING);
+            return true;
+        } catch (IOException e) {
+            try {
+                Files.deleteIfExists(tmp);
+            } catch (IOException ignored) {}
+            if (writeWarned.compareAndSet(false, true)) LOGGER.warn("Shader disk cache write failed for {}", target, e);
+            return false;
+        }
+    }
+
+    private static void write(Path tmp, byte[] payload) throws IOException {
+        final CRC32 c = new CRC32();
+        c.update(payload, 0, payload.length);
+        final ByteBuffer header = ByteBuffer.allocate(HEADER_BYTES);
+        header.putInt(MAGIC).putInt(payload.length).putInt((int) c.getValue()).flip();
+        final ByteBuffer[] parts = { header, ByteBuffer.wrap(payload) };
+        try (FileChannel ch = FileChannel.open(tmp, StandardOpenOption.CREATE, StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING)) {
+            while (header.hasRemaining() || parts[1].hasRemaining()) ch.write(parts);
+        }
+    }
+
+    public static String getString(Key key) {
+        final byte[] payload = get(key);
+        return payload == null ? null : new String(payload, StandardCharsets.UTF_8);
+    }
+
+    public static void putString(Key key, String value) {
+        put(key, value.getBytes(StandardCharsets.UTF_8));
+    }
+
+    public static Map<String, String> getStrings(Key key) {
+        final byte[] payload = get(key);
+        if (payload == null) return null;
+        try {
+            final ByteBuffer in = ByteBuffer.wrap(payload);
+            final int count = readCount(in);
+            final Map<String, String> out = new LinkedHashMap<>();
+            for (int i = 0; i < count; i++) {
+                out.put(readStr(in), readStr(in));
+            }
+            return out;
+        } catch (RuntimeException e) {
+            return null;
+        }
+    }
+
+    public static void putStrings(Key key, Map<String, String> values) {
+        int size = 0;
+        for (String v : values.values()) size += (v == null ? 0 : v.length()) + 64;
+        final ByteArrayOutputStream bytes = new ByteArrayOutputStream(size);
+        try (DataOutputStream out = new DataOutputStream(bytes)) {
+            out.writeInt(values.size());
+            for (Map.Entry<String, String> e : values.entrySet()) {
+                writeStr(out, e.getKey());
+                writeStr(out, e.getValue());
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+        put(key, bytes.toByteArray());
+    }
+
+    public static Blob getBlob(Key key) {
+        final byte[] payload = get(key);
+        if (payload == null) return null;
+        try {
+            final ByteBuffer in = ByteBuffer.wrap(payload);
+            final String tag = readStr(in);
+            final byte[] data = readBytes(in);
+            return new Blob(tag, data);
+        } catch (RuntimeException e) {
+            return null;
+        }
+    }
+
+    public static boolean putBlob(Key key, String tag, byte[] data) {
+        final ByteArrayOutputStream bytes = new ByteArrayOutputStream(data.length + 64);
+        try (DataOutputStream out = new DataOutputStream(bytes)) {
+            writeStr(out, tag);
+            writeBytes(out, data);
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+        return put(key, bytes.toByteArray());
+    }
+
+    public record Blob(String tag, byte[] data) {}
+
+    public static void remove(Key key) {
+        final Path r = root;
+        if (r == null) return;
+        try {
+            Files.deleteIfExists(key.path(r));
+        } catch (IOException ignored) {}
+    }
+
+    public static void retainLayer(String layer, Set<String> keep) {
+        final Path r = root;
+        if (r == null) return;
+        final Path dir = r.resolve(layer);
+        if (!Files.isDirectory(dir)) return;
+        final List<Path> files = new ArrayList<>();
+        try (Stream<Path> list = Files.list(dir)) {
+            list.forEach(files::add);
+        } catch (IOException e) {
+            LOGGER.warn("Shader disk cache could not list {}", dir, e);
+            return;
+        }
+        for (Path p : files) {
+            final String name = p.getFileName().toString();
+            if (!name.endsWith(".bin")) continue; // in-flight writes are still .tmp
+            if (keep != null && keep.contains(name.substring(0, name.length() - 4))) continue;
+            try {
+                Files.deleteIfExists(p);
+            } catch (IOException ignored) {}
+        }
+    }
+
+    public static void touchLayer(String layer) {
+        final Path r = root;
+        if (r == null) return;
+        final Path dir = r.resolve(layer);
+        try {
+            Files.createDirectories(dir);
+            Files.setLastModifiedTime(dir, FileTime.fromMillis(System.currentTimeMillis()));
+        } catch (IOException e) {
+            LOGGER.warn("Shader disk cache could not mark {} as used", dir, e);
+        }
+    }
+
+    public static void keepNewestSubLayers(String layer, int keep) {
+        final Path r = root;
+        if (r == null) return;
+        final Path dir = r.resolve(layer);
+        if (!Files.isDirectory(dir)) return;
+        final List<Path> subLayers = new ArrayList<>();
+        try (Stream<Path> list = Files.list(dir)) {
+            list.filter(Files::isDirectory).forEach(subLayers::add);
+        } catch (IOException e) {
+            LOGGER.warn("Shader disk cache could not list {}", dir, e);
+            return;
+        }
+        subLayers.sort(Comparator.comparingLong(ShaderDiskCache::lastModifiedMillis).reversed());
+        for (int i = keep; i < subLayers.size(); i++) {
+            deleteRecursively(subLayers.get(i));
+        }
+    }
+
+    public static void deleteLayer(String layer) {
+        final Path r = root;
+        if (r != null) deleteRecursively(r.resolve(layer));
+    }
+
+    private static long lastModifiedMillis(Path path) {
+        try {
+            return Files.getLastModifiedTime(path).toMillis();
+        } catch (IOException e) {
+            return 0L;
+        }
+    }
+
+    private static void deleteRecursively(Path dir) {
+        if (!Files.exists(dir)) return;
+        final List<Path> paths = new ArrayList<>();
+        try (Stream<Path> walk = Files.walk(dir)) {
+            walk.forEach(paths::add);
+        } catch (IOException e) {
+            LOGGER.warn("Shader disk cache could not list {}", dir, e);
+            return;
+        }
+        Collections.reverse(paths);
+        for (Path p : paths) {
+            try {
+                Files.deleteIfExists(p);
+            } catch (IOException ignored) {}
+        }
+    }
+
+    static void enforceCap(Path dir, long maxBytes) {
+        try {
+            final long[] total = {0};
+            Files.walkFileTree(dir, new SimpleFileVisitor<>() {
+                @Override public FileVisitResult visitFile(Path p, BasicFileAttributes a) { total[0] += a.size(); return FileVisitResult.CONTINUE; }
+                @Override public FileVisitResult visitFileFailed(Path p, IOException e) { return FileVisitResult.CONTINUE; }
+            });
+            if (total[0] > maxBytes) wipe(dir);
+        } catch (IOException | RuntimeException e) {
+            LOGGER.warn("Shader disk cache cap check failed", e);
+        }
+    }
+
+    private static void wipe(Path dir) throws IOException {
+        final List<Path> paths = new ArrayList<>();
+        try (Stream<Path> walk = Files.walk(dir)) {
+            walk.forEach(paths::add);
+        }
+        for (Path p : paths) {
+            if (Files.isRegularFile(p) && !p.getFileName().toString().equals("salt")) Files.deleteIfExists(p);
+        }
+    }
+
+    public static final class Key {
+        private final String layer;
+        private final MessageDigest md;
+        private String hex;
+
+        Key(String layer) {
+            this.layer = layer;
+            try {
+                md = MessageDigest.getInstance("SHA-256");
+            } catch (NoSuchAlgorithmException e) {
+                throw new IllegalStateException(e);
+            }
+            str(layer);
+        }
+
+        public Key str(String s) {
+            if (s == null) return i(-1);
+            final byte[] utf8 = s.getBytes(StandardCharsets.UTF_8);
+            i(utf8.length);
+            md.update(utf8);
+            return this;
+        }
+
+        public Key i(int v) {
+            md.update((byte) (v >>> 24));
+            md.update((byte) (v >>> 16));
+            md.update((byte) (v >>> 8));
+            md.update((byte) v);
+            return this;
+        }
+
+        public Key b(boolean v) {
+            md.update((byte) (v ? 1 : 0));
+            return this;
+        }
+
+        public Key bytes(byte[] v) {
+            i(v.length);
+            md.update(v);
+            return this;
+        }
+
+        public Key sortedStrs(Collection<String> values) {
+            final String[] sorted = values.toArray(new String[0]);
+            Arrays.sort(sorted);
+            i(sorted.length);
+            for (String s : sorted) str(s);
+            return this;
+        }
+
+        public String hex() {
+            if (hex == null) {
+                final byte[] digest = md.digest();
+                final StringBuilder sb = new StringBuilder(digest.length * 2);
+                for (byte d : digest) {
+                    sb.append(Character.forDigit((d >>> 4) & 0xF, 16)).append(Character.forDigit(d & 0xF, 16));
+                }
+                hex = sb.toString();
+            }
+            return hex;
+        }
+
+        Path path(Path root) {
+            return root.resolve(layer).resolve(hex() + ".bin");
+        }
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/shader/SpirvCompiler.java

@@ -35,6 +35,11 @@ public final class SpirvCompiler {
     private static final int CACHE_MAX = 256;
     private static final Object2ObjectLinkedOpenHashMap<CacheKey, byte[]> CACHE = new Object2ObjectLinkedOpenHashMap<>();
 
+    @Lwjgl3Aware
+    private static final class Toolchain {
+        static final String ID = ShaderCacheIO.libraryId(Shaderc.getLibrary());
+    }
+
     private record CacheKey(String source, int shaderKind, Options opts) {}
 
     private SpirvCompiler() {}
@@ -53,6 +58,10 @@ public final class SpirvCompiler {
     public record Result(@Nullable ByteBuffer spirv, @Nullable String error, @Nullable Path dumpPath) {}
 
     public static Result compile(String source, int shaderKind, String debugName, Options opts) {
+        return compile(source, shaderKind, debugName, opts, true);
+    }
+
+    public static Result compile(String source, int shaderKind, String debugName, Options opts, boolean diskCache) {
         final String cleanSrc = source.indexOf('\0') >= 0 ? source.replace("\0", "") : source;
 
         final CacheKey key = new CacheKey(cleanSrc, shaderKind, opts);
@@ -60,12 +69,37 @@ public final class SpirvCompiler {
         synchronized (CACHE) {
             cached = CACHE.getAndMoveToFirst(key);
         }
-        if (cached != null) {
-            final ByteBuffer copy = MemoryUtil.memAlloc(cached.length);
-            copy.put(cached).flip();
-            return new Result(copy, null, null);
+        if (cached != null) return new Result(ShaderCacheIO.toNative(cached), null, null);
+
+        ShaderDiskCache.Key diskKey = null;
+        if (diskCache && ShaderDiskCache.isEnabled()) {
+            diskKey = diskKey(cleanSrc, shaderKind, opts);
+            final byte[] disk = ShaderDiskCache.get(diskKey);
+            if (disk != null) {
+                ShaderCacheIO.lruPut(CACHE, key, disk, CACHE_MAX);
+                return new Result(ShaderCacheIO.toNative(disk), null, null);
+            }
         }
 
+        final Result result = compileUncached(cleanSrc, shaderKind, debugName, opts);
+        final ByteBuffer spirv = result.spirv();
+        if (spirv != null) {
+            final byte[] heap = ShaderCacheIO.toHeap(spirv);
+            ShaderCacheIO.lruPut(CACHE, key, heap, CACHE_MAX);
+            if (diskKey != null) ShaderDiskCache.put(diskKey, heap);
+        }
+        return result;
+    }
+
+    public static String toolchainId() {
+        return Toolchain.ID;
+    }
+
+    static ShaderDiskCache.Key diskKey(String cleanSrc, int shaderKind, Options opts) {
+        return ShaderDiskCache.key("spirv").str(toolchainId()).str(cleanSrc).i(shaderKind).str(opts.toString());
+    }
+
+    private static Result compileUncached(String cleanSrc, int shaderKind, String debugName, Options opts) {
         final long compiler = COMPILER.get();
         final long optionsHandle = Shaderc.shaderc_compile_options_initialize();
         if (optionsHandle == 0L) {
@@ -98,12 +132,6 @@ public final class SpirvCompiler {
                 final ByteBuffer copy = MemoryUtil.memAlloc(spirv.remaining());
                 copy.put(spirv);
                 copy.flip();
-                final byte[] heap = new byte[copy.remaining()];
-                copy.duplicate().get(heap);
-                synchronized (CACHE) {
-                    CACHE.putAndMoveToFirst(key, heap);
-                    while (CACHE.size() > CACHE_MAX) CACHE.removeLast();
-                }
                 return new Result(copy, null, null);
             } finally {
                 if (result != 0L) Shaderc.shaderc_result_release(result);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/AlphaStateStack.java

@@ -14,8 +14,8 @@ public final class AlphaStateStack extends AlphaState implements CowStateStack<A
 
     public AlphaStateStack(int id) {
         cow.id = id;
-        stack = new AlphaState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new AlphaState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new AlphaState();
         }
     }
@@ -25,6 +25,11 @@ public final class AlphaStateStack extends AlphaState implements CowStateStack<A
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return VanillaStateLayer.isHeld(vanillaLayer) || !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/BlendStateStack.java

@@ -17,8 +17,8 @@ public final class BlendStateStack extends BlendState implements CowStateStack<B
 
     public BlendStateStack(int id) {
         cow.id = id;
-        stack = new BlendState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new BlendState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new BlendState();
         }
     }
@@ -28,6 +28,11 @@ public final class BlendStateStack extends BlendState implements CowStateStack<B
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return funcUnknown || VanillaStateLayer.isHeld(vanillaLayer) || !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/BooleanStateStack.java

@@ -44,7 +44,7 @@ public class BooleanStateStack extends BooleanState implements CowStateStack<Boo
     public BooleanStateStack(int glCap, boolean initialState, boolean ffpStateOnly) {
         super(glCap, ffpStateOnly);
         this.enabled = initialState;
-        stack = new boolean[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
+        stack = new boolean[GLStateManager.STATE_SLOTS];
     }
 
     @Override
@@ -52,6 +52,11 @@ public class BooleanStateStack extends BooleanState implements CowStateStack<Boo
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return stateUnknown || (vanillaLayer != null && vanillaLayer.isOverrideHeld()) || enabled != stack[slot];
+    }
+
     @Override
     public void captureSlot(int slot) {
         stack[slot] = vanillaValue();

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/Color4Stack.java

@@ -10,8 +10,8 @@ public final class Color4Stack extends Color4 implements CowStateStack<Color4Sta
 
     public Color4Stack(int id) {
         cow.id = id;
-        stack = new Color4[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new Color4[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new Color4();
         }
     }
@@ -33,6 +33,11 @@ public final class Color4Stack extends Color4 implements CowStateStack<Color4Sta
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/ColorMaskStack.java

@@ -15,8 +15,8 @@ public final class ColorMaskStack extends ColorMask implements CowStateStack<Col
 
     public ColorMaskStack(int id) {
         cow.id = id;
-        stack = new ColorMask[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new ColorMask[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new ColorMask();
         }
     }
@@ -26,6 +26,11 @@ public final class ColorMaskStack extends ColorMask implements CowStateStack<Col
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return VanillaStateLayer.isHeld(vanillaLayer) || !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));
@@ -39,6 +44,12 @@ public final class ColorMaskStack extends ColorMask implements CowStateStack<Col
         }
     }
 
+    public ColorMask readEffective(ColorMask out) {
+        out.set(this);
+        VanillaStateLayer.capture(vanillaLayer, out);
+        return out;
+    }
+
     @Override
     public boolean topSlotChanged() {
         return !cow.isEmpty() && !sameAs(stack[cow.top()]);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/CowDepths.java

@@ -35,12 +35,14 @@ public final class CowDepths {
     }
 
     public int claim(int depth) {
-        if (depth <= 0) return -1;
-        if (pointer > 0 && slotDepth[pointer - 1] == depth) return -1;
         slotDepth[pointer] = depth;
         return pointer++;
     }
 
+    public boolean claimedAt(int depth) {
+        return pointer > 0 && slotDepth[pointer - 1] == depth;
+    }
+
     public int claimUnconditional() {
         slotDepth[pointer] = -1;
         return pointer++;

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/CowDispatch.java

@@ -101,6 +101,36 @@ public final class CowDispatch {
         };
     }
 
+    public static boolean slotChanged(byte kind, CowStateStack<?> s, int slot) {
+        return switch (kind) {
+            case BLEND -> ((BlendStateStack) s).slotChanged(slot);
+            case BOOLEAN -> ((BooleanStateStack) s).slotChanged(slot);
+            case CLIP_PLANE_BOOLEAN -> ((ClipPlaneBooleanState) s).slotChanged(slot);
+            case TEXTURE_UNIT_BOOLEAN -> ((TextureUnitBooleanStateStack) s).slotChanged(slot);
+            case COLOR_MASK -> ((ColorMaskStack) s).slotChanged(slot);
+            case LIGHT_STATE -> ((LightStateStack) s).slotChanged(slot);
+            case MATERIAL -> ((MaterialStateStack) s).slotChanged(slot);
+            case STENCIL -> ((StencilStateStack) s).slotChanged(slot);
+            case MATRIX_MODE -> ((MatrixModeStack) s).slotChanged(slot);
+            case LIGHT_MODEL -> ((LightModelStateStack) s).slotChanged(slot);
+            case ALPHA -> ((AlphaStateStack) s).slotChanged(slot);
+            case POINT -> ((PointStateStack) s).slotChanged(slot);
+            case FOG -> ((FogStateStack) s).slotChanged(slot);
+            case VEC4F -> ((Vec4fStack) s).slotChanged(slot);
+            case VEC3F -> ((Vec3fStack) s).slotChanged(slot);
+            case INTEGER -> ((IntegerStateStack) s).slotChanged(slot);
+            case DEPTH -> ((DepthStateStack) s).slotChanged(slot);
+            case VIEWPORT -> ((ViewPortStateStack) s).slotChanged(slot);
+            case POLYGON -> ((PolygonStateStack) s).slotChanged(slot);
+            case COLOR4 -> ((Color4Stack) s).slotChanged(slot);
+            case LINE -> ((LineStateStack) s).slotChanged(slot);
+            case TEXTURE_BINDING -> ((TextureBindingStack) s).slotChanged(slot);
+            case TEX_ENV -> ((TexEnvState) s).slotChanged(slot);
+            case SCISSOR -> ((ScissorStateStack) s).slotChanged(slot);
+            default -> throw new IllegalStateException("Unknown kind: " + kind);
+        };
+    }
+
     public static void restoreSlot(byte kind, CowStateStack<?> s, int slot) {
         switch (kind) {
             case BLEND -> ((BlendStateStack) s).restoreSlot(slot);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/CowStateStack.java

@@ -20,6 +20,8 @@ public interface CowStateStack<T> extends IStateStack<T> {
 
     void restoreSlot(int slot);
 
+    boolean slotChanged(int slot);
+
     default int stackId() {
         return cowDepths().id;
     }
@@ -51,11 +53,10 @@ public interface CowStateStack<T> extends IStateStack<T> {
         final CowDepths d = cowDepths();
         final GLContextState o = d.owner;
         if (o == null) return;
-        final int s = d.claim(o.attribDepth);
-        if (s >= 0) {
-            captureSlot(s);
-            GLStateManager.registerModifiedState(o, d.id);
-        }
+        final int depth = o.attribDepth;
+        if (depth == 0 || d.claimedAt(depth) || !o.savesState(d.id)) return;
+        captureSlot(d.claim(depth));
+        GLStateManager.registerModifiedState(o, d.id);
     }
 
     @Override

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/DepthStateStack.java

@@ -17,8 +17,8 @@ public final class DepthStateStack extends DepthState implements CowStateStack<D
 
     public DepthStateStack(int id) {
         cow.id = id;
-        stack = new DepthState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new DepthState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new DepthState();
         }
     }
@@ -28,6 +28,11 @@ public final class DepthStateStack extends DepthState implements CowStateStack<D
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return VanillaStateLayer.isHeld(vanillaLayer) || !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         VanillaStateLayer.capture(vanillaLayer, stack[s].set(this));

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/FogStateStack.java

@@ -10,8 +10,8 @@ public final class FogStateStack extends FogState implements CowStateStack<FogSt
 
     public FogStateStack(int id) {
         cow.id = id;
-        stack = new FogState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new FogState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new FogState();
         }
     }
@@ -21,6 +21,11 @@ public final class FogStateStack extends FogState implements CowStateStack<FogSt
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/IntegerStateStack.java

@@ -11,8 +11,8 @@ public final class IntegerStateStack extends IntegerState implements CowStateSta
     public IntegerStateStack(int val, int id) {
         cow.id = id;
         setValue(val);
-        stack = new IntegerState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new IntegerState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new IntegerState();
             stack[i].setValue(val);
         }
@@ -30,6 +30,11 @@ public final class IntegerStateStack extends IntegerState implements CowStateSta
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/LightModelStateStack.java

@@ -11,8 +11,8 @@ public final class LightModelStateStack extends LightModelState implements CowSt
     public LightModelStateStack(int id) {
         super();
         cow.id = id;
-        stack = new LightModelState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new LightModelState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new LightModelState();
         }
     }
@@ -22,6 +22,11 @@ public final class LightModelStateStack extends LightModelState implements CowSt
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/LightStateStack.java

@@ -11,8 +11,8 @@ public final class LightStateStack extends LightState implements CowStateStack<L
     public LightStateStack(int light, int id) {
         super(light);
         cow.id = id;
-        stack = new LightState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new LightState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new LightState(light);
         }
     }
@@ -22,6 +22,11 @@ public final class LightStateStack extends LightState implements CowStateStack<L
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/LineStateStack.java

@@ -11,8 +11,8 @@ public final class LineStateStack extends LineState implements CowStateStack<Lin
 
     public LineStateStack(int id) {
         cow.id = id;
-        stack = new LineState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new LineState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new LineState();
         }
     }
@@ -22,6 +22,11 @@ public final class LineStateStack extends LineState implements CowStateStack<Lin
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/MaterialStateStack.java

@@ -11,8 +11,8 @@ public final class MaterialStateStack extends MaterialState implements CowStateS
     public MaterialStateStack(int face, int id) {
         super(face);
         cow.id = id;
-        stack = new MaterialState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new MaterialState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new MaterialState(face);
         }
     }
@@ -22,6 +22,11 @@ public final class MaterialStateStack extends MaterialState implements CowStateS
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/MatrixModeStack.java

@@ -10,8 +10,8 @@ public final class MatrixModeStack extends MatrixMode implements CowStateStack<M
 
     public MatrixModeStack(int id) {
         cow.id = id;
-        stack = new MatrixMode[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new MatrixMode[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new MatrixMode();
         }
     }
@@ -21,6 +21,11 @@ public final class MatrixModeStack extends MatrixMode implements CowStateStack<M
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/PointStateStack.java

@@ -11,8 +11,8 @@ public final class PointStateStack extends PointState implements CowStateStack<P
 
     public PointStateStack(int id) {
         cow.id = id;
-        stack = new PointState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new PointState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new PointState();
         }
     }
@@ -22,6 +22,11 @@ public final class PointStateStack extends PointState implements CowStateStack<P
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/PolygonStateStack.java

@@ -11,8 +11,8 @@ public final class PolygonStateStack extends PolygonState implements CowStateSta
 
     public PolygonStateStack(int id) {
         cow.id = id;
-        stack = new PolygonState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new PolygonState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new PolygonState();
         }
     }
@@ -22,6 +22,11 @@ public final class PolygonStateStack extends PolygonState implements CowStateSta
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/RetainedState.java

@@ -0,0 +1,12 @@
+package com.gtnewhorizons.angelica.glsm.stacks;
+
+public final class RetainedState {
+    public int[] ids = new int[64];
+    public int count;
+    public int program;
+    public long programGen;
+
+    public void ensureCapacity(int capacity) {
+        if (ids.length < capacity) ids = new int[capacity];
+    }
+}

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/ScissorStateStack.java

@@ -11,8 +11,8 @@ public final class ScissorStateStack extends ScissorState implements CowStateSta
 
     public ScissorStateStack(int id) {
         cow.id = id;
-        stack = new ScissorState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new ScissorState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new ScissorState();
         }
     }
@@ -22,6 +22,11 @@ public final class ScissorStateStack extends ScissorState implements CowStateSta
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/StencilStateStack.java

@@ -11,8 +11,8 @@ public final class StencilStateStack extends StencilState implements CowStateSta
 
     public StencilStateStack(int id) {
         cow.id = id;
-        stack = new StencilState[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new StencilState[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new StencilState();
         }
     }
@@ -22,6 +22,11 @@ public final class StencilStateStack extends StencilState implements CowStateSta
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/TextureBindingStack.java

@@ -12,8 +12,8 @@ public final class TextureBindingStack extends TextureBinding implements CowStat
     public TextureBindingStack(int id, int unit) {
         cow = new CowDepths(StateSet.R_TEXTURE, unit);
         cow.id = id;
-        stack = new TextureBinding[GLStateManager.MAX_ATTRIB_STACK_DEPTH];
-        for (int i = 0; i < GLStateManager.MAX_ATTRIB_STACK_DEPTH; i++) {
+        stack = new TextureBinding[GLStateManager.STATE_SLOTS];
+        for (int i = 0; i < GLStateManager.STATE_SLOTS; i++) {
             stack[i] = new TextureBinding();
         }
     }
@@ -23,6 +23,11 @@ public final class TextureBindingStack extends TextureBinding implements CowStat
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return !sameAs(stack[slot]);
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s].set(this);

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/TextureUnitBooleanStateStack.java

@@ -24,7 +24,10 @@ public final class TextureUnitBooleanStateStack extends BooleanStateStack {
 
     @Override
     public void setEnabled(boolean enabled) {
-        beforeModify();
+        if (!GLStateManager.isCachingEnabled() || enabled != this.enabled) {
+            GLStateManager.beforeUncapturedTextureUnitChange(glCap, unitIndex);
+            beforeModify();
+        }
         setEnabledWithUnitSwitch(enabled);
     }
 

glsm/src/main/java/com/gtnewhorizons/angelica/glsm/stacks/Vec3fStack.java

@@ -15,7 +15,7 @@ public final class Vec3fStack implements CowStateStack<Vec3fStack> {
     public Vec3fStack(Vector3f value, int id) {
         this.value = value;
         cow.id = id;
-        stack = new float[GLStateManager.MAX_ATTRIB_STACK_DEPTH][3];
+        stack = new float[GLStateManager.STATE_SLOTS][3];
     }
 
     @Override
@@ -23,6 +23,11 @@ public final class Vec3fStack implements CowStateStack<Vec3fStack> {
         return cow;
     }
 
+    @Override
+    public boolean slotChanged(int slot) {
+        return value.x != stack[slot][0] || value.y != stack[slot][1] || value.z != stack[slot][2];
+    }
+
     @Override
     public void captureSlot(int s) {
         stack[s][0] = value.x;