wasm gc: support JS exceptions

core/src/main/resources/org/teavm/backend/wasm/wasm-gc-runtime.js

@@ -110,16 +110,17 @@ TeaVM.wasm = function() {
     }
 
     function jsoImports(imports) {
-
         let javaObjectSymbol = Symbol("javaObject");
         let functionsSymbol = Symbol("functions");
         let functionOriginSymbol = Symbol("functionOrigin");
+        let javaExceptionSymbol = Symbol("javaException");
 
         let jsWrappers = new WeakMap();
         let javaWrappers = new WeakMap();
         let primitiveWrappers = new Map();
         let primitiveFinalization = new FinalizationRegistry(token => primitiveFinalization.delete(token));
         let hashCodes = new WeakMap();
+        let javaExceptionWrappers = new WeakMap();
         let lastHashCode = 2463534242;
         let nextHashCode = () => {
             let x = lastHashCode;
@@ -156,6 +157,53 @@ TeaVM.wasm = function() {
                 obj[prop] = value;
             }
         }
+        function javaExceptionToJs(e) {
+            if (e instanceof WebAssembly.Exception) {
+                let tag = exports["javaException"];
+                if (e.is(tag)) {
+                    let javaException = e.getArg(tag, 0);
+                    let extracted = extractException(javaException);
+                    if (extracted !== null) {
+                        return extracted;
+                    }
+                    let wrapperRef = javaExceptionWrappers.get(javaException);
+                    if (typeof wrapperRef != "undefined") {
+                        let wrapper = wrapperRef.deref();
+                        if (typeof wrapper !== "undefined") {
+                            return wrapper;
+                        }
+                    }
+                    let wrapper = new Error();
+                    javaExceptionWrappers.set(javaException, new WeakRef(wrapper));
+                    wrapper[javaExceptionSymbol] = javaException;
+                    return wrapper;
+                }
+            }
+            return e;
+        }
+        function jsExceptionAsJava(e) {
+            if (javaExceptionSymbol in e) {
+                return e[javaExceptionSymbol];
+            } else {
+                return exports["teavm.js.wrapException"](e);
+            }
+        }
+        function rethrowJsAsJava(e) {
+            exports["teavm.js.throwException"](jsExceptionAsJava(e));
+        }
+        function extractException(e) {
+            return exports["teavm.js.extractException"](e);
+        }
+        function rethrowJavaAsJs(e) {
+            throw javaExceptionToJs(e);
+        }
+        function getProperty(obj, prop) {
+            try {
+                return obj !== null ? obj[prop] : getGlobalName(prop)
+            } catch (e) {
+                rethrowJsAsJava(e);
+            }
+        }
         imports.teavmJso = {
             emptyString: () => "",
             stringFromCharCode: code => String.fromCharCode(code),
@@ -166,11 +214,17 @@ TeaVM.wasm = function() {
             appendToArray: (array, e) => array.push(e),
             unwrapBoolean: value => value ? 1 : 0,
             wrapBoolean: value => !!value,
-            getProperty: (obj, prop) => obj !== null ? obj[prop] : getGlobalName(prop),
+            getProperty: getProperty,
-            getPropertyPure: (obj, prop) => obj !== null ? obj[prop] : getGlobalName(prop),
+            getPropertyPure: getProperty,
             setProperty: setProperty,
             setPropertyPure: setProperty,
-            global: getGlobalName,
+            global(name) {
+                try {
+                    return getGlobalName(name);
+                } catch (e) {
+                    rethrowJsAsJava(e);
+                }
+            },
             createClass(name) {
                 let fn = new Function(
                     "javaObjectSymbol",
@@ -184,18 +238,30 @@ TeaVM.wasm = function() {
             },
             defineMethod(cls, name, fn) {
                 cls.prototype[name] = function(...args) {
+                    try {
                         return fn(this, ...args);
+                    } catch (e) {
+                        rethrowJavaAsJs(e);
+                    }
                 }
             },
             defineProperty(cls, name, getFn, setFn) {
                 let descriptor = {
                     get() {
+                        try {
                             return getFn(this);
+                        } catch (e) {
+                            rethrowJavaAsJs(e);
+                        }
                     }
                 };
                 if (setFn !== null) {
                     descriptor.set = function(value) {
+                        try {
                             setFn(this, value);
+                        } catch (e) {
+                            rethrowJavaAsJs(e);
+                        }
                     }
                 }
                 Object.defineProperty(cls.prototype, name, descriptor);
@@ -239,7 +305,15 @@ TeaVM.wasm = function() {
                         return origin;
                     }
                 }
-                return { [property]: fn };
+                return {
+                    [property]: function(...args) {
+                        try {
+                            return fn(...args);
+                        } catch (e) {
+                            rethrowJavaAsJs(e);
+                        }
+                    }
+                };
             },
             wrapObject(obj) {
                 if (obj === null) {
@@ -298,14 +372,19 @@ TeaVM.wasm = function() {
                 }
             },
             apply: (instance, method, args) => {
+                try {
                     if (instance === null) {
                         let fn = getGlobalName(method);
                         return fn(...args);
                     } else {
                         return instance[method](...args);
                     }
+                } catch (e) {
+                    rethrowJsAsJava(e);
+                }
             },
-            concatArray: (a, b) => a.concat(b)
+            concatArray: (a, b) => a.concat(b),
+            getJavaException: e => e[javaExceptionSymbol]
         };
         for (let name of ["wrapByte", "wrapShort", "wrapChar", "wrapInt", "wrapFloat", "wrapDouble", "unwrapByte",
                 "unwrapShort", "unwrapChar", "unwrapInt", "unwrapFloat", "unwrapDouble"]) {
@@ -313,10 +392,27 @@ TeaVM.wasm = function() {
         }
         for (let i = 0; i < 32; ++i) {
             imports.teavmJso["createFunction" + i] = (...args) => new Function(...args);
-            imports.teavmJso["callFunction" + i] = (fn, ...args) => fn(...args);
+            imports.teavmJso["callFunction" + i] = (fn, ...args) => {
-            imports.teavmJso["callMethod" + i] = (instance, method, ...args) =>
+                try {
-                instance !== null ? instance[method](...args) : getGlobalName(method)(...args);
+                    return fn(...args);
-            imports.teavmJso["construct" + i] = (constructor, ...args) => new constructor(...args);
+                } catch (e) {
+                    rethrowJsAsJava(e);
+                }
+            };
+            imports.teavmJso["callMethod" + i] = (instance, method, ...args) => {
+                try {
+                    return instance !== null ? instance[method](...args) : getGlobalName(method)(...args);
+                } catch (e) {
+                    rethrowJsAsJava(e);
+                }
+            }
+            imports.teavmJso["construct" + i] = (constructor, ...args) => {
+                try {
+                    return new constructor(...args);
+                } catch (e) {
+                    rethrowJsAsJava(e);
+                }
+            }
             imports.teavmJso["arrayOf" + i] = (...args) => args
         }
     }

jso/core/build.gradle.kts

@@ -28,6 +28,7 @@ configurations {
 
 dependencies {
     "teavm"(project(":jso:impl"))
+    compileOnly(project(":interop:core"))
 }
 
 teavmPublish {

jso/core/src/main/java/org/teavm/jso/JSExceptions.java

@@ -15,10 +15,13 @@
  */
 package org.teavm.jso;
 
+import org.teavm.interop.Import;
+
 public final class JSExceptions {
     private JSExceptions() {
     }
 
+    @Import(name = "getJavaException", module = "teavmJso")
     public static native Throwable getJavaException(JSObject e);
 
     public static native JSObject getJSException(Throwable e);

jso/impl/src/main/java/org/teavm/jso/impl/JSValueMarshaller.java

@@ -68,7 +68,7 @@ class JSValueMarshaller {
             String className = ((ValueType.Object) type).getClassName();
             ClassReader cls = classSource.get(className);
             if (cls != null && cls.getAnnotations().get(JSFunctor.class.getName()) != null) {
-                return wrapFunctor(location, var, cls);
+                return wrapFunctor(location, var, cls, jsType);
             }
         }
         return wrap(var, type, jsType, location.getSourceLocation(), byRef);
@@ -83,12 +83,13 @@ class JSValueMarshaller {
                 .count() == 1;
     }
 
-    private Variable wrapFunctor(CallLocation location, Variable var, ClassReader type) {
+    private Variable wrapFunctor(CallLocation location, Variable var, ClassReader type, JSType jsType) {
         if (!isProperFunctor(type)) {
             diagnostics.error(location, "Wrong functor: {{c0}}", type.getName());
             return var;
         }
 
+        if (jsType == JSType.JAVA) {
             var unwrapNative = new InvokeInstruction();
             unwrapNative.setLocation(location.getSourceLocation());
             unwrapNative.setType(InvocationType.SPECIAL);
@@ -97,6 +98,7 @@ class JSValueMarshaller {
             unwrapNative.setReceiver(program.createVariable());
             replacement.add(unwrapNative);
             var = unwrapNative.getReceiver();
+        }
 
         String name = type.getMethods().stream()
                 .filter(method -> method.hasModifier(ElementModifier.ABSTRACT))

jso/impl/src/main/java/org/teavm/jso/impl/wasmgc/WasmGCExceptionWrapper.java

@@ -0,0 +1,35 @@
+/*
+ *  Copyright 2024 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.jso.impl.wasmgc;
+
+import org.teavm.jso.JSObject;
+import org.teavm.jso.core.JSError;
+
+class WasmGCExceptionWrapper extends RuntimeException {
+    final JSObject jsException;
+
+    WasmGCExceptionWrapper(JSObject jsException) {
+        this.jsException = jsException;
+    }
+
+    @Override
+    public String getMessage() {
+        var message = jsException instanceof JSError
+                ? ((JSError) jsException).getMessage()
+                : jsException.toString();
+        return "(JavaScript) Error: " + message;
+    }
+}

jso/impl/src/main/java/org/teavm/jso/impl/wasmgc/WasmGCJSDependencies.java

@@ -28,16 +28,7 @@ import org.teavm.model.MethodReference;
 class WasmGCJSDependencies extends AbstractDependencyListener {
     @Override
     public void started(DependencyAgent agent) {
-        agent.linkMethod(STRING_TO_JS)
+        reachUtilities(agent);
-                .propagate(1, agent.getType("java.lang.String"))
-                .use();
-
-        var jsToString = agent.linkMethod(JS_TO_STRING);
-        jsToString.getResult().propagate(agent.getType("java.lang.String"));
-        jsToString.use();
-
-        agent.linkMethod(new MethodReference(JSWrapper.class, "createWrapper", JSObject.class, Object.class))
-                .use();
     }
 
     @Override
@@ -46,6 +37,26 @@ class WasmGCJSDependencies extends AbstractDependencyListener {
             if (method.getMethod().getName().equals("jsArrayItem")) {
                 method.getVariable(1).getArrayItem().connect(method.getResult());
             }
+        } else if (method.getMethod().getOwnerName().equals(JSWrapper.class.getName())) {
+            if (method.getMethod().getName().equals("wrap")) {
+                agent.linkMethod(new MethodReference(JSWrapper.class, "createWrapper", JSObject.class, Object.class))
+                        .use();
             }
         }
     }
+
+    private void reachUtilities(DependencyAgent agent) {
+        agent.linkMethod(STRING_TO_JS)
+                .propagate(1, agent.getType("java.lang.String"))
+                .use();
+
+        var jsToString = agent.linkMethod(JS_TO_STRING);
+        jsToString.getResult().propagate(agent.getType("java.lang.String"));
+        jsToString.use();
+
+        agent.linkMethod(new MethodReference(WasmGCJSRuntime.class, "wrapException", JSObject.class, Throwable.class))
+                .use();
+        agent.linkMethod(new MethodReference(WasmGCJSRuntime.class, "extractException", Throwable.class,
+                JSObject.class)).use();
+    }
+}

jso/impl/src/main/java/org/teavm/jso/impl/wasmgc/WasmGCJSRuntime.java

@@ -65,4 +65,12 @@ final class WasmGCJSRuntime {
 
     @Import(name = "charAt", module = "teavmJso")
     static native char charAt(JSObject str, int index);
+
+    static Throwable wrapException(JSObject obj) {
+        return new WasmGCExceptionWrapper(obj);
+    }
+
+    static JSObject extractException(Throwable e) {
+        return e instanceof WasmGCExceptionWrapper ? ((WasmGCExceptionWrapper) e).jsException : null;
+    }
 }

jso/impl/src/main/java/org/teavm/jso/impl/wasmgc/WasmGCJsoCommonGenerator.java

@@ -22,20 +22,30 @@ import java.util.function.Consumer;
 import org.teavm.backend.javascript.rendering.AstWriter;
 import org.teavm.backend.wasm.model.WasmFunction;
 import org.teavm.backend.wasm.model.WasmGlobal;
+import org.teavm.backend.wasm.model.WasmLocal;
 import org.teavm.backend.wasm.model.WasmType;
 import org.teavm.backend.wasm.model.expression.WasmCall;
+import org.teavm.backend.wasm.model.expression.WasmCast;
 import org.teavm.backend.wasm.model.expression.WasmExpression;
+import org.teavm.backend.wasm.model.expression.WasmExternConversion;
+import org.teavm.backend.wasm.model.expression.WasmExternConversionType;
 import org.teavm.backend.wasm.model.expression.WasmGetGlobal;
+import org.teavm.backend.wasm.model.expression.WasmGetLocal;
 import org.teavm.backend.wasm.model.expression.WasmNullConstant;
 import org.teavm.backend.wasm.model.expression.WasmSetGlobal;
+import org.teavm.backend.wasm.model.expression.WasmThrow;
+import org.teavm.jso.JSObject;
 import org.teavm.jso.impl.JSBodyAstEmitter;
 import org.teavm.jso.impl.JSBodyBloatedEmitter;
 import org.teavm.jso.impl.JSBodyEmitter;
+import org.teavm.model.MethodReference;
+import org.teavm.model.ValueType;
 
 class WasmGCJsoCommonGenerator {
     private WasmGCJSFunctions jsFunctions;
     private boolean initialized;
     private List<Consumer<WasmFunction>> initializerParts = new ArrayList<>();
+    private boolean rethrowExported;
 
     WasmGCJsoCommonGenerator(WasmGCJSFunctions jsFunctions) {
         this.jsFunctions = jsFunctions;
@@ -47,6 +57,7 @@ class WasmGCJsoCommonGenerator {
         }
         initialized = true;
         context.addToInitializer(this::writeToInitializer);
+        exportRethrowException(context);
     }
 
     private void writeToInitializer(WasmFunction function) {
@@ -55,7 +66,8 @@ class WasmGCJsoCommonGenerator {
         }
     }
 
-    void addInitializerPart(Consumer<WasmFunction> part) {
+    void addInitializerPart(WasmGCJsoContext context, Consumer<WasmFunction> part) {
+        initialize(context);
         initializerParts.add(part);
     }
 
@@ -114,4 +126,37 @@ class WasmGCJsoCommonGenerator {
     WasmExpression stringToJs(WasmGCJsoContext context, WasmExpression str) {
         return new WasmCall(stringToJsFunction(context), str);
     }
+
+    private void exportRethrowException(WasmGCJsoContext context) {
+        if (rethrowExported) {
+            return;
+        }
+        rethrowExported = true;
+        var fn = context.functions().forStaticMethod(new MethodReference(WasmGCJSRuntime.class, "wrapException",
+                JSObject.class, Throwable.class));
+        fn.setExportName("teavm.js.wrapException");
+
+        fn = context.functions().forStaticMethod(new MethodReference(WasmGCJSRuntime.class, "extractException",
+                Throwable.class, JSObject.class));
+        fn.setExportName("teavm.js.extractException");
+
+        createThrowExceptionFunction(context);
+    }
+
+    private void createThrowExceptionFunction(WasmGCJsoContext context) {
+        var fn = new WasmFunction(context.functionTypes().of(null, WasmType.Reference.EXTERN));
+        fn.setName(context.names().topLevel("teavm@throwException"));
+        fn.setExportName("teavm.js.throwException");
+        context.module().functions.add(fn);
+
+        var exceptionLocal = new WasmLocal(WasmType.Reference.EXTERN);
+        fn.add(exceptionLocal);
+
+        var asAny = new WasmExternConversion(WasmExternConversionType.EXTERN_TO_ANY, new WasmGetLocal(exceptionLocal));
+        var throwableType = (WasmType.Reference) context.typeMapper().mapType(ValueType.parse(Throwable.class));
+        var asThrowable = new WasmCast(asAny, throwableType);
+        var throwExpr = new WasmThrow(context.exceptionTag());
+        throwExpr.getArguments().add(asThrowable);
+        fn.getBody().add(throwExpr);
+    }
 }

jso/impl/src/main/java/org/teavm/jso/impl/wasmgc/WasmGCJsoContext.java

@@ -19,11 +19,13 @@ import java.util.function.Consumer;
 import org.teavm.backend.wasm.BaseWasmFunctionRepository;
 import org.teavm.backend.wasm.WasmFunctionTypes;
 import org.teavm.backend.wasm.generate.gc.WasmGCNameProvider;
+import org.teavm.backend.wasm.generate.gc.classes.WasmGCTypeMapper;
 import org.teavm.backend.wasm.generate.gc.strings.WasmGCStringProvider;
 import org.teavm.backend.wasm.generators.gc.WasmGCCustomGeneratorContext;
 import org.teavm.backend.wasm.intrinsics.gc.WasmGCIntrinsicContext;
 import org.teavm.backend.wasm.model.WasmFunction;
 import org.teavm.backend.wasm.model.WasmModule;
+import org.teavm.backend.wasm.model.WasmTag;
 
 interface WasmGCJsoContext {
     WasmModule module();
@@ -36,6 +38,10 @@ interface WasmGCJsoContext {
 
     WasmGCStringProvider strings();
 
+    WasmGCTypeMapper typeMapper();
+
+    WasmTag exceptionTag();
+
     void addToInitializer(Consumer<WasmFunction> initializerContributor);
 
     static WasmGCJsoContext wrap(WasmGCIntrinsicContext context) {
@@ -65,6 +71,16 @@ interface WasmGCJsoContext {
                 return context.strings();
             }
 
+            @Override
+            public WasmGCTypeMapper typeMapper() {
+                return context.typeMapper();
+            }
+
+            @Override
+            public WasmTag exceptionTag() {
+                return context.exceptionTag();
+            }
+
             @Override
             public void addToInitializer(Consumer<WasmFunction> initializerContributor) {
                 context.addToInitializer(initializerContributor);
@@ -99,6 +115,16 @@ interface WasmGCJsoContext {
                 return context.strings();
             }
 
+            @Override
+            public WasmGCTypeMapper typeMapper() {
+                return context.typeMapper();
+            }
+
+            @Override
+            public WasmTag exceptionTag() {
+                return context.exceptionTag();
+            }
+
             @Override
             public void addToInitializer(Consumer<WasmFunction> initializerContributor) {
                 context.addToInitializer(initializerContributor);

tests/src/test/java/org/teavm/jso/test/ExceptionsTest.java

@@ -27,12 +27,13 @@ import org.teavm.jso.core.JSError;
 import org.teavm.junit.EachTestCompiledSeparately;
 import org.teavm.junit.OnlyPlatform;
 import org.teavm.junit.SkipJVM;
+import org.teavm.junit.SkipPlatform;
 import org.teavm.junit.TeaVMTestRunner;
 import org.teavm.junit.TestPlatform;
 
 @RunWith(TeaVMTestRunner.class)
 @SkipJVM
-@OnlyPlatform(TestPlatform.JAVASCRIPT)
+@OnlyPlatform({TestPlatform.JAVASCRIPT, TestPlatform.WEBASSEMBLY_GC})
 @EachTestCompiledSeparately
 public class ExceptionsTest {
     @Test
@@ -102,6 +103,7 @@ public class ExceptionsTest {
     }
 
     @Test
+    @SkipPlatform(TestPlatform.WEBASSEMBLY_GC)
     public void catchNativeExceptionAsRuntimeException() {
         StringBuilder sb = new StringBuilder();
         try {