Add @@toStringTag for WebAssembly classes

R=titzer@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2625133005
Cr-Commit-Position: refs/heads/master@{#42379}

src/wasm/wasm-js.cc

@@ -778,14 +778,12 @@ void WasmJs::Install(Isolate* isolate) {
   Handle<JSObject> webassembly = factory->NewJSObject(cons, TENURED);
   PropertyAttributes attributes = static_cast<PropertyAttributes>(DONT_ENUM);
   JSObject::AddProperty(global, name, webassembly, attributes);
-
-  // Setup compile
+  PropertyAttributes ro_attributes =
+      static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY);
+  JSObject::AddProperty(webassembly, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly"), ro_attributes);
   InstallFunc(isolate, webassembly, "compile", WebAssemblyCompile, 1);
-
-  // Setup validate
   InstallFunc(isolate, webassembly, "validate", WebAssemblyValidate, 1);
-
-  // Setup instantiate
   InstallFunc(isolate, webassembly, "instantiate", WebAssemblyInstantiate, 1);
 
   // Setup Module
@@ -798,12 +796,14 @@ void WasmJs::Install(Isolate* isolate) {
       i::JS_API_OBJECT_TYPE, i::JSObject::kHeaderSize +
                              WasmModuleObject::kFieldCount * i::kPointerSize);
   JSFunction::SetInitialMap(module_constructor, module_map, module_proto);
-  JSObject::AddProperty(module_proto, isolate->factory()->constructor_string(),
-                        module_constructor, DONT_ENUM);
   InstallFunc(isolate, module_constructor, "imports", WebAssemblyModuleImports,
               1);
   InstallFunc(isolate, module_constructor, "exports", WebAssemblyModuleExports,
               1);
+  JSObject::AddProperty(module_proto, isolate->factory()->constructor_string(),
+                        module_constructor, DONT_ENUM);
+  JSObject::AddProperty(module_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Module"), ro_attributes);
 
   // Setup Instance
   Handle<JSFunction> instance_constructor =
@@ -818,6 +818,8 @@ void WasmJs::Install(Isolate* isolate) {
   JSObject::AddProperty(instance_proto,
                         isolate->factory()->constructor_string(),
                         instance_constructor, DONT_ENUM);
+  JSObject::AddProperty(instance_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Instance"), ro_attributes);
 
   // Setup Table
   Handle<JSFunction> table_constructor =
@@ -835,6 +837,8 @@ void WasmJs::Install(Isolate* isolate) {
   InstallFunc(isolate, table_proto, "grow", WebAssemblyTableGrow, 1);
   InstallFunc(isolate, table_proto, "get", WebAssemblyTableGet, 1);
   InstallFunc(isolate, table_proto, "set", WebAssemblyTableSet, 2);
+  JSObject::AddProperty(table_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Table"), ro_attributes);
 
   // Setup Memory
   Handle<JSFunction> memory_constructor =
@@ -850,6 +854,8 @@ void WasmJs::Install(Isolate* isolate) {
                         memory_constructor, DONT_ENUM);
   InstallFunc(isolate, memory_proto, "grow", WebAssemblyMemoryGrow, 1);
   InstallGetter(isolate, memory_proto, "buffer", WebAssemblyMemoryGetBuffer);
+  JSObject::AddProperty(memory_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Memory"), ro_attributes);
 
   // Setup errors
   attributes = static_cast<PropertyAttributes>(DONT_ENUM);

test/mjsunit/wasm/js-api.js

@@ -70,7 +70,7 @@ assertEq(wasmDesc.configurable, true);
 
 // 'WebAssembly' object
 assertEq(WebAssembly, wasmDesc.value);
-//TODO assertEq(String(WebAssembly), "[object WebAssembly]");
+assertEq(String(WebAssembly), "[object WebAssembly]");
 
 // 'WebAssembly.CompileError'
 let compileErrorDesc = Object.getOwnPropertyDescriptor(WebAssembly, 'CompileError');
@@ -155,7 +155,7 @@ assertEq(moduleProtoDesc.configurable, false);
 // 'WebAssembly.Module.prototype' object
 let moduleProto = Module.prototype;
 assertEq(moduleProto, moduleProtoDesc.value);
-assertEq(String(moduleProto), "[object Object]");
+assertEq(String(moduleProto), "[object WebAssembly.Module]");
 assertEq(Object.getPrototypeOf(moduleProto), Object.prototype);
 
 // 'WebAssembly.Module' instance objects
@@ -163,7 +163,7 @@ let emptyModule = new Module(emptyModuleBinary);
 let importingModule = new Module(importingModuleBinary);
 let exportingModule = new Module(exportingModuleBinary);
 assertEq(typeof emptyModule, "object");
-//TODO assertEq(String(emptyModule), "[object WebAssembly.Module]");
+assertEq(String(emptyModule), "[object WebAssembly.Module]");
 assertEq(Object.getPrototypeOf(emptyModule), moduleProto);
 
 // 'WebAssembly.Module.imports' data property
@@ -285,14 +285,14 @@ assertEq(instanceProtoDesc.configurable, false);
 // 'WebAssembly.Instance.prototype' object
 let instanceProto = Instance.prototype;
 assertEq(instanceProto, instanceProtoDesc.value);
-assertEq(String(instanceProto), "[object Object]");
+assertEq(String(instanceProto), "[object WebAssembly.Instance]");
 assertEq(Object.getPrototypeOf(instanceProto), Object.prototype);
 
 // 'WebAssembly.Instance' instance objects
 let exportingInstance = new Instance(exportingModule);
 assertEq(typeof exportingInstance, "object");
-//TODO:name assertEq(String(exportingInstance), "[object WebAssembly.Instance]");
-//TODO assertEq(Object.getPrototypeOf(exportingInstance), instanceProto);
+assertEq(String(exportingInstance), "[object WebAssembly.Instance]");
+assertEq(Object.getPrototypeOf(exportingInstance), instanceProto);
 
 // 'WebAssembly.Instance' 'exports' data property
 let instanceExportsDesc = Object.getOwnPropertyDescriptor(exportingInstance, 'exports');
@@ -342,13 +342,13 @@ assertEq(memoryProtoDesc.configurable, false);
 // 'WebAssembly.Memory.prototype' object
 let memoryProto = Memory.prototype;
 assertEq(memoryProto, memoryProtoDesc.value);
-assertEq(String(memoryProto), "[object Object]");
+assertEq(String(memoryProto), "[object WebAssembly.Memory]");
 assertEq(Object.getPrototypeOf(memoryProto), Object.prototype);
 
 // 'WebAssembly.Memory' instance objects
 let mem1 = new Memory({initial:1});
 assertEq(typeof mem1, "object");
-//TODO assertEq(String(mem1), "[object WebAssembly.Memory]");
+assertEq(String(mem1), "[object WebAssembly.Memory]");
 assertEq(Object.getPrototypeOf(mem1), memoryProto);
 
 // 'WebAssembly.Memory.prototype.buffer' accessor property
@@ -434,13 +434,13 @@ assertEq(tableProtoDesc.configurable, false);
 // 'WebAssembly.Table.prototype' object
 let tableProto = Table.prototype;
 assertEq(tableProto, tableProtoDesc.value);
-assertEq(String(tableProto), "[object Object]");
+assertEq(String(tableProto), "[object WebAssembly.Table]");
 assertEq(Object.getPrototypeOf(tableProto), Object.prototype);
 
 // 'WebAssembly.Table' instance objects
 let tbl1 = new Table({initial:2, element:"anyfunc"});
 assertEq(typeof tbl1, "object");
-//TODO:name assertEq(String(tbl1), "[object WebAssembly.Table]");
+assertEq(String(tbl1), "[object WebAssembly.Table]");
 assertEq(Object.getPrototypeOf(tbl1), tableProto);
 
 // 'WebAssembly.Table.prototype.length' accessor data property