[wasm][eh] Wasm exceptions are not JS errors

Context: https://github.com/WebAssembly/exception-handling/pull/197

This change removes the wasm exception -> JS Error inheritance.

R=jkummerow@chromium.org

Bug: v8:8091
Change-Id: I479f16fe03d4d77d2ecd8409e96f9a3c063912b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3688401
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80997}

src/compiler/types.cc

@@ -285,6 +285,7 @@ Type::bitset BitsetType::Lub(const MapRefLike& map) {
     case WASM_SUSPENDER_OBJECT_TYPE:
     case WASM_TABLE_OBJECT_TYPE:
     case WASM_TAG_OBJECT_TYPE:
+    case WASM_EXCEPTION_PACKAGE_TYPE:
     case WASM_VALUE_OBJECT_TYPE:
 #endif  // V8_ENABLE_WEBASSEMBLY
     case WEAK_CELL_TYPE:

src/diagnostics/objects-debug.cc

@@ -263,6 +263,9 @@ void HeapObject::HeapObjectVerify(Isolate* isolate) {
     case WASM_VALUE_OBJECT_TYPE:
       WasmValueObject::cast(*this).WasmValueObjectVerify(isolate);
       break;
+    case WASM_EXCEPTION_PACKAGE_TYPE:
+      WasmExceptionPackage::cast(*this).WasmExceptionPackageVerify(isolate);
+      break;
 #endif  // V8_ENABLE_WEBASSEMBLY
     case JS_SET_KEY_VALUE_ITERATOR_TYPE:
     case JS_SET_VALUE_ITERATOR_TYPE:
@@ -1793,6 +1796,11 @@ void WasmValueObject::WasmValueObjectVerify(Isolate* isolate) {
   CHECK(IsWasmValueObject());
 }
 
+void WasmExceptionPackage::WasmExceptionPackageVerify(Isolate* isolate) {
+  JSObjectVerify(isolate);
+  CHECK(IsWasmExceptionPackage());
+}
+
 void WasmExportedFunctionData::WasmExportedFunctionDataVerify(
     Isolate* isolate) {
   TorqueGeneratedClassVerifiers::WasmExportedFunctionDataVerify(*this, isolate);

src/diagnostics/objects-printer.cc

@@ -205,6 +205,9 @@ void HeapObject::HeapObjectPrint(std::ostream& os) {
     case WASM_VALUE_OBJECT_TYPE:
       WasmValueObject::cast(*this).WasmValueObjectPrint(os);
       break;
+    case WASM_EXCEPTION_PACKAGE_TYPE:
+      WasmExceptionPackage::cast(*this).WasmExceptionPackagePrint(os);
+      break;
 #endif  // V8_ENABLE_WEBASSEMBLY
     case CODE_TYPE:
       Code::cast(*this).CodePrint(os);
@@ -2059,6 +2062,11 @@ void WasmCapiFunctionData::WasmCapiFunctionDataPrint(std::ostream& os) {
   os << "\n";
 }
 
+void WasmExceptionPackage::WasmExceptionPackagePrint(std::ostream& os) {
+  PrintHeader(os, "WasmExceptionPackage");
+  os << "\n";
+}
+
 void WasmModuleObject::WasmModuleObjectPrint(std::ostream& os) {
   PrintHeader(os, "WasmModuleObject");
   os << "\n - module: " << module();

src/heap/factory.cc

@@ -2294,7 +2294,6 @@ DEFINE_ERROR(TypeError, type_error)
 DEFINE_ERROR(WasmCompileError, wasm_compile_error)
 DEFINE_ERROR(WasmLinkError, wasm_link_error)
 DEFINE_ERROR(WasmRuntimeError, wasm_runtime_error)
-DEFINE_ERROR(WasmExceptionError, wasm_exception_error)
 #undef DEFINE_ERROR
 
 Handle<JSObject> Factory::NewFunctionPrototype(Handle<JSFunction> function) {

src/init/bootstrapper.cc

@@ -2758,10 +2758,6 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
     // -- R u n t i m e E r r o r
     InstallError(isolate_, dummy, factory->RuntimeError_string(),
                  Context::WASM_RUNTIME_ERROR_FUNCTION_INDEX);
-
-    // -- W e b A s s e m b l y . E x c e p t i o n
-    InstallError(isolate_, dummy, factory->WebAssemblyException_string(),
-                 Context::WASM_EXCEPTION_ERROR_FUNCTION_INDEX);
   }
 
   // Initialize the embedder data slot.

src/objects/contexts.h

@@ -361,8 +361,6 @@ enum ContextLookupFlags {
   V(WASM_LINK_ERROR_FUNCTION_INDEX, JSFunction, wasm_link_error_function)      \
   V(WASM_RUNTIME_ERROR_FUNCTION_INDEX, JSFunction,                             \
     wasm_runtime_error_function)                                               \
-  V(WASM_EXCEPTION_ERROR_FUNCTION_INDEX, JSFunction,                           \
-    wasm_exception_error_function)                                             \
   V(WEAKMAP_SET_INDEX, JSFunction, weakmap_set)                                \
   V(WEAKMAP_GET_INDEX, JSFunction, weakmap_get)                                \
   V(WEAKMAP_DELETE_INDEX, JSFunction, weakmap_delete)                          \

src/objects/js-objects.cc

@@ -2528,6 +2528,8 @@ int JSObject::GetHeaderSize(InstanceType type,
       return WasmValueObject::kHeaderSize;
     case WASM_TAG_OBJECT_TYPE:
       return WasmTagObject::kHeaderSize;
+    case WASM_EXCEPTION_PACKAGE_TYPE:
+      return WasmExceptionPackage::kHeaderSize;
 #endif  // V8_ENABLE_WEBASSEMBLY
     default: {
       // Special type check for API Objects because they are in a large variable

src/objects/map.cc

@@ -311,6 +311,7 @@ VisitorId Map::GetVisitorId(Map map) {
 #endif  // V8_INTL_SUPPORT
 #if V8_ENABLE_WEBASSEMBLY
     case WASM_TAG_OBJECT_TYPE:
+    case WASM_EXCEPTION_PACKAGE_TYPE:
     case WASM_GLOBAL_OBJECT_TYPE:
     case WASM_MEMORY_OBJECT_TYPE:
     case WASM_MODULE_OBJECT_TYPE:

src/objects/objects-body-descriptors-inl.h

@@ -1151,6 +1151,8 @@ auto BodyDescriptorApply(InstanceType type, Args&&... args) {
       return CALL_APPLY(WasmArray);
     case WASM_CAPI_FUNCTION_DATA_TYPE:
       return CALL_APPLY(WasmCapiFunctionData);
+    case WASM_EXCEPTION_PACKAGE_TYPE:
+      return CALL_APPLY(WasmExceptionPackage);
     case WASM_EXPORTED_FUNCTION_DATA_TYPE:
       return CALL_APPLY(WasmExportedFunctionData);
     case WASM_INTERNAL_FUNCTION_TYPE:

src/objects/objects-inl.h

@@ -400,14 +400,6 @@ DEF_GETTER(HeapObject, IsObjectHashTable, bool) {
 
 DEF_GETTER(HeapObject, IsHashTableBase, bool) { return IsHashTable(cage_base); }
 
-#if V8_ENABLE_WEBASSEMBLY
-DEF_GETTER(HeapObject, IsWasmExceptionPackage, bool) {
-  // It is not possible to check for the existence of certain properties on the
-  // underlying {JSReceiver} here because that requires calling handlified code.
-  return IsJSReceiver(cage_base);
-}
-#endif  // V8_ENABLE_WEBASSEMBLY
-
 bool Object::IsPrimitive() const {
   if (IsSmi()) return true;
   HeapObject this_heap_object = HeapObject::cast(*this);

src/objects/objects.h

@@ -95,6 +95,7 @@
 //         - JSSegments            // If V8_INTL_SUPPORT enabled.
 //         - JSSegmentIterator     // If V8_INTL_SUPPORT enabled.
 //         - JSV8BreakIterator     // If V8_INTL_SUPPORT enabled.
+//         - WasmExceptionPackage
 //         - WasmTagObject
 //         - WasmGlobalObject
 //         - WasmInstanceObject

src/wasm/wasm-js.cc

@@ -2304,10 +2304,6 @@ void WebAssemblyExceptionGetArg(
 
   auto this_tag =
       i::WasmExceptionPackage::GetExceptionTag(i_isolate, exception);
-  if (this_tag->IsUndefined()) {
-    thrower.TypeError("Expected a WebAssembly.Exception object");
-    return;
-  }
   DCHECK(this_tag->IsWasmExceptionTag());
   if (tag->tag() != *this_tag) {
     thrower.TypeError("First argument does not match the exception tag");
@@ -2441,10 +2437,6 @@ void WebAssemblyExceptionIs(const v8::FunctionCallbackInfo<v8::Value>& args) {
   if (thrower.error()) return;
 
   auto tag = i::WasmExceptionPackage::GetExceptionTag(i_isolate, exception);
-  if (tag->IsUndefined()) {
-    thrower.TypeError("Expected a WebAssembly.Exception object");
-    return;
-  }
   DCHECK(tag->IsWasmExceptionTag());
 
   auto maybe_tag = GetFirstArgumentAsTag(args, &thrower);
@@ -3023,21 +3015,13 @@ void WasmJs::Install(Isolate* isolate, bool exposed_on_global_object) {
     Handle<JSFunction> exception_constructor = InstallConstructorFunc(
         isolate, webassembly, "Exception", WebAssemblyException);
     SetDummyInstanceTemplate(isolate, exception_constructor);
-    Handle<Map> exception_map(isolate->native_context()
-                                  ->wasm_exception_error_function()
-                                  .initial_map(),
-                              isolate);
-    Handle<JSObject> exception_proto(
-        JSObject::cast(isolate->native_context()
-                           ->wasm_exception_error_function()
-                           .instance_prototype()),
-        isolate);
+    Handle<JSObject> exception_proto = SetupConstructor(
+        isolate, exception_constructor, i::WASM_EXCEPTION_PACKAGE_TYPE,
+        WasmExceptionPackage::kHeaderSize, "WebAssembly.Exception");
     InstallFunc(isolate, exception_proto, "getArg", WebAssemblyExceptionGetArg,
                 2);
     InstallFunc(isolate, exception_proto, "is", WebAssemblyExceptionIs, 1);
     context->set_wasm_exception_constructor(*exception_constructor);
-    JSFunction::SetInitialMap(isolate, exception_constructor, exception_map,
-                              exception_proto);
   }
 
   // Setup Suspender.

src/wasm/wasm-objects.cc

@@ -1692,8 +1692,9 @@ Handle<WasmExceptionPackage> WasmExceptionPackage::New(
 Handle<WasmExceptionPackage> WasmExceptionPackage::New(
     Isolate* isolate, Handle<WasmExceptionTag> exception_tag,
     Handle<FixedArray> values) {
-  Handle<JSObject> exception = isolate->factory()->NewWasmExceptionError(
-      MessageTemplate::kWasmExceptionError);
+  Handle<JSFunction> exception_cons(
+      isolate->native_context()->wasm_exception_constructor(), isolate);
+  Handle<JSObject> exception = isolate->factory()->NewJSObject(exception_cons);
   CHECK(!Object::SetProperty(isolate, exception,
                              isolate->factory()->wasm_exception_tag_symbol(),
                              exception_tag, StoreOrigin::kMaybeKeyed,

src/wasm/wasm-objects.h

@@ -570,6 +570,8 @@ class V8_EXPORT_PRIVATE WasmExceptionPackage : public JSObject {
   static uint32_t GetEncodedSize(const wasm::WasmTag* tag);
 
   DECL_CAST(WasmExceptionPackage)
+  DECL_PRINTER(WasmExceptionPackage)
+  DECL_VERIFIER(WasmExceptionPackage)
   OBJECT_CONSTRUCTORS(WasmExceptionPackage, JSObject);
 };
 

src/wasm/wasm-objects.tq

@@ -114,6 +114,8 @@ extern class WasmExceptionTag extends Struct {
   index: Smi;
 }
 
+extern class WasmExceptionPackage extends JSObject;
+
 extern class WasmModuleObject extends JSObject {
   managed_native_module: ManagedWasmNativeModule;
   export_wrappers: FixedArray;

test/message/fail/wasm-exception-rethrow.out

-wasm-function[0]:0x32: WebAssembly.Exception: wasm exception
-WebAssembly.Exception: wasm exception
-    at rethrow0 (wasm://wasm/f019909a:wasm-function[0]:0x32)
-    at *%(basename)s:21:18
+undefined:0: [object WebAssembly.Exception]

test/message/fail/wasm-exception-throw.out

-wasm-function[0]:0x2e: WebAssembly.Exception: wasm exception
-WebAssembly.Exception: wasm exception
-    at throw0 (wasm://wasm/e4cabeba:wasm-function[0]:0x2e)
-    at *%(basename)s:17:18
+undefined:0: [object WebAssembly.Exception]

test/mjsunit/regress/wasm/regress-8094.js

@@ -26,4 +26,4 @@ try {
 // that no extraneous properties exist. Setting such properties could be
 // observable by JavaScript and could break compatibility.
 assertInstanceof(exception, WebAssembly.Exception);
-assertArrayEquals(["stack", "message"], Object.getOwnPropertyNames(exception));
+assertArrayEquals([], Object.getOwnPropertyNames(exception));

test/mjsunit/wasm/exceptions-api.js

@@ -75,6 +75,7 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
   // Check prototype.
   assertSame(WebAssembly.Exception.prototype, js_exception.__proto__);
   assertTrue(js_exception instanceof WebAssembly.Exception);
+  assertFalse(js_exception instanceof Error);
 
   // Check prototype of a thrown exception.
   let builder = new WasmModuleBuilder();
@@ -236,5 +237,5 @@ function TestGetArgHelper(types_str, types, values) {
   assertFalse(exception.is(tag2));
 
   assertThrows(() => exception.is.apply({}, tag1), TypeError,
-      /Expected a WebAssembly.Exception object/);
+      /Receiver is not a WebAssembly.Exception/);
 })();

test/wasm-js/wasm-js.status

@@ -9,7 +9,6 @@
   'wpt/idlharness': [SKIP],
   # Failing WPT tests
   'wpt/exception/getArg.tentative': [FAIL],
-  'wpt/exception/toString.tentative': [FAIL],
   'wpt/exception/type.tentative': [FAIL],
   'wpt/function/constructor.tentative': [FAIL],
   'wpt/function/table.tentative': [FAIL],

tools/v8heapconst.py

@@ -264,14 +264,15 @@ INSTANCE_TYPES = {
   2139: "JS_TEMPORAL_ZONED_DATE_TIME_TYPE",
   2140: "JS_V8_BREAK_ITERATOR_TYPE",
   2141: "JS_WEAK_REF_TYPE",
-  2142: "WASM_GLOBAL_OBJECT_TYPE",
-  2143: "WASM_INSTANCE_OBJECT_TYPE",
-  2144: "WASM_MEMORY_OBJECT_TYPE",
-  2145: "WASM_MODULE_OBJECT_TYPE",
-  2146: "WASM_SUSPENDER_OBJECT_TYPE",
-  2147: "WASM_TABLE_OBJECT_TYPE",
-  2148: "WASM_TAG_OBJECT_TYPE",
-  2149: "WASM_VALUE_OBJECT_TYPE",
+  2142: "WASM_EXCEPTION_PACKAGE_TYPE",
+  2143: "WASM_GLOBAL_OBJECT_TYPE",
+  2144: "WASM_INSTANCE_OBJECT_TYPE",
+  2145: "WASM_MEMORY_OBJECT_TYPE",
+  2146: "WASM_MODULE_OBJECT_TYPE",
+  2147: "WASM_SUSPENDER_OBJECT_TYPE",
+  2148: "WASM_TABLE_OBJECT_TYPE",
+  2149: "WASM_TAG_OBJECT_TYPE",
+  2150: "WASM_VALUE_OBJECT_TYPE",
 }
 
 # List of known V8 maps.