[wasm] Set up Table and Memory constructors

src/wasm/wasm-js.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api-natives.h"
 #include "src/api.h"
 #include "src/asmjs/asm-js.h"
 #include "src/asmjs/asm-typer.h"
 #include "src/asmjs/asm-wasm-builder.h"
 #include "src/assert-scope.h"
@@ skipping 11 matching lines @@
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-result.h"
 
 typedef uint8_t byte;
 
 using v8::internal::wasm::ErrorThrower;
 
 namespace v8 {
 
 namespace {
+i::Handle<i::String> v8_str(i::Isolate* isolate, const char* str) {
+  return isolate->factory()->NewStringFromAsciiChecked(str);
+}
+Local<String> v8_str(Isolate* isolate, const char* str) {
+  return Utils::ToLocal(v8_str(reinterpret_cast<i::Isolate*>(isolate), str));
+}
+
 struct RawBuffer {
   const byte* start;
   const byte* end;
   size_t size() { return static_cast<size_t>(end - start); }
 };
 
 RawBuffer GetRawBufferSource(
     v8::Local<v8::Value> source, ErrorThrower* thrower) {
   const byte* start = nullptr;
   const byte* end = nullptr;
@@ skipping 29 matching lines @@
 
   return {start, end};
 }
 
 void VerifyModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
   HandleScope scope(args.GetIsolate());
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
   ErrorThrower thrower(isolate, "Wasm.verifyModule()");
 
   if (args.Length() < 1) {
-    thrower.Error("Argument 0 must be a buffer source");
+    thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
   RawBuffer buffer = GetRawBufferSource(args[0], &thrower);
   if (thrower.error()) return;
 
   i::Zone zone(isolate->allocator());
   internal::wasm::ModuleResult result =
       internal::wasm::DecodeWasmModule(isolate, &zone, buffer.start, buffer.end,
                                        true, internal::wasm::kWasmOrigin);
 
   if (result.failed()) {
     thrower.Failed("", result);
   }
 
   if (result.val) delete result.val;
 }
 
 void VerifyFunction(const v8::FunctionCallbackInfo<v8::Value>& args) {
   HandleScope scope(args.GetIsolate());
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
   ErrorThrower thrower(isolate, "Wasm.verifyFunction()");
 
   if (args.Length() < 1) {
-    thrower.Error("Argument 0 must be a buffer source");
+    thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
   RawBuffer buffer = GetRawBufferSource(args[0], &thrower);
   if (thrower.error()) return;
 
   internal::wasm::FunctionResult result;
   {
     // Verification of a single function shouldn't allocate.
     i::DisallowHeapAllocation no_allocation;
     i::Zone zone(isolate->allocator());
@@ skipping 44 matching lines @@
   }
   return object;
 }
 
 void InstantiateModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
   HandleScope scope(args.GetIsolate());
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(args.GetIsolate());
   ErrorThrower thrower(isolate, "Wasm.instantiateModule()");
 
   if (args.Length() < 1) {
-    thrower.Error("Argument 0 must be a buffer source");
+    thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
   RawBuffer buffer = GetRawBufferSource(args[0], &thrower);
   if (buffer.start == nullptr) return;
 
   InstantiateModule(args, buffer.start, buffer.end, &thrower);
 }
 
 static i::MaybeHandle<i::JSObject> CreateModuleObject(
     v8::Isolate* isolate, const v8::Local<v8::Value> source,
     ErrorThrower* thrower) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   i::MaybeHandle<i::JSObject> nothing;
 
   RawBuffer buffer = GetRawBufferSource(source, thrower);
   if (buffer.start == nullptr) return i::MaybeHandle<i::JSObject>();
 
   DCHECK(source->IsArrayBuffer() || source->IsTypedArray());
   return i::wasm::CreateModuleObjectFromBytes(
       i_isolate, buffer.start, buffer.end, thrower,
       i::wasm::ModuleOrigin::kWasmOrigin);
 }
 
+bool BrandCheck(Isolate* isolate, i::Handle<i::Object> value,
+                i::Handle<i::Symbol> sym, const char* msg) {
+  if (value->IsJSObject()) {
+    i::Handle<i::JSObject> object = i::Handle<i::JSObject>::cast(value);
+    Maybe<bool> has_brand = i::JSObject::HasOwnProperty(object, sym);
+    if (has_brand.IsNothing()) return false;
+    if (has_brand.ToChecked()) return true;
+  }
+  v8::Local<v8::Value> e = v8::Exception::TypeError(v8_str(isolate, msg));
+  isolate->ThrowException(e);
+  return false;
+}
+
 void WebAssemblyCompile(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
   HandleScope scope(isolate);
   ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
                        "WebAssembly.compile()");
 
   if (args.Length() < 1) {
-    thrower.Error("Argument 0 must be a buffer source");
+    thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
   i::MaybeHandle<i::JSObject> module_obj =
       CreateModuleObject(isolate, args[0], &thrower);
 
   Local<Context> context = isolate->GetCurrentContext();
   v8::Local<v8::Promise::Resolver> resolver;
   if (!v8::Promise::Resolver::New(context).ToLocal(&resolver)) return;
   if (thrower.error()) {
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
   } else {
     resolver->Resolve(context, Utils::ToLocal(module_obj.ToHandleChecked()));
   }
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(resolver->GetPromise());
 }
 
 void WebAssemblyModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
   HandleScope scope(isolate);
   ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
                        "WebAssembly.Module()");
 
   if (args.Length() < 1) {
-    thrower.Error("Argument 0 must be a buffer source");
+    thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
   i::MaybeHandle<i::JSObject> module_obj =
       CreateModuleObject(isolate, args[0], &thrower);
   if (module_obj.is_null()) return;
 
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(Utils::ToLocal(module_obj.ToHandleChecked()));
 }
 
 void WebAssemblyInstance(const v8::FunctionCallbackInfo<v8::Value>& args) {
   HandleScope scope(args.GetIsolate());
   v8::Isolate* isolate = args.GetIsolate();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
 
   ErrorThrower thrower(i_isolate, "WebAssembly.Instance()");
 
   if (args.Length() < 1) {
-    thrower.Error(
-        "Argument 0 must be provided, and must be a WebAssembly.Module object");
+    thrower.TypeError("Argument 0 must be a WebAssembly.Module");
     return;
   }
 
   Local<Context> context = isolate->GetCurrentContext();
   i::Handle<i::Context> i_context = Utils::OpenHandle(*context);
-  i::Handle<i::Symbol> module_sym(i_context->wasm_module_sym());
-  i::MaybeHandle<i::Object> source =
-      i::Object::GetProperty(Utils::OpenHandle(*args[0]), module_sym);
-  if (source.is_null() || source.ToHandleChecked()->IsUndefined(i_isolate)) {
-    thrower.Error("Argument 0 must be a WebAssembly.Module");
+  if (!BrandCheck(isolate, Utils::OpenHandle(*args[0]),
+                  i::Handle<i::Symbol>(i_context->wasm_module_sym()),
+                  "Argument 0 must be a WebAssembly.Module")) {
     return;
   }
 
   Local<Object> obj = Local<Object>::Cast(args[0]);
 
   i::Handle<i::JSObject> module_obj =
       i::Handle<i::JSObject>::cast(v8::Utils::OpenHandle(*obj));
   if (module_obj->GetInternalFieldCount() < 1 ||
       !module_obj->GetInternalField(0)->IsFixedArray()) {
-    thrower.Error("Argument 0 is an invalid WebAssembly.Module");
+    thrower.TypeError("Argument 0 is an invalid WebAssembly.Module");
     return;
   }
 
   i::Handle<i::JSReceiver> ffi = i::Handle<i::JSObject>::null();
   if (args.Length() > 1 && args[1]->IsObject()) {
     Local<Object> obj = Local<Object>::Cast(args[1]);
     ffi = i::Handle<i::JSReceiver>::cast(v8::Utils::OpenHandle(*obj));
   }
 
   i::Handle<i::JSArrayBuffer> memory = i::Handle<i::JSArrayBuffer>::null();
   if (args.Length() > 2 && args[2]->IsArrayBuffer()) {
     Local<Object> obj = Local<Object>::Cast(args[2]);
     i::Handle<i::Object> mem_obj = v8::Utils::OpenHandle(*obj);
     memory = i::Handle<i::JSArrayBuffer>(i::JSArrayBuffer::cast(*mem_obj));
   }
   i::MaybeHandle<i::JSObject> instance =
       i::wasm::WasmModule::Instantiate(i_isolate, module_obj, ffi, memory);
   if (instance.is_null()) {
     thrower.Error("Could not instantiate module");
     return;
   }
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(Utils::ToLocal(instance.ToHandleChecked()));
 }
+
+void WebAssemblyTable(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  v8::Isolate* isolate = args.GetIsolate();
+  HandleScope scope(isolate);
+  ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
+                       "WebAssembly.Module()");
+  if (args.Length() < 1 || !args[0]->IsObject()) {
+    thrower.TypeError("Argument 0 must be a table descriptor");
+    return;
+  }
+  Local<Context> context = isolate->GetCurrentContext();
+  Local<v8::Object> descriptor = args[0]->ToObject(context).ToLocalChecked();
+  // The descriptor's 'element'.
+  {
+    v8::MaybeLocal<v8::Value> maybe =
+        descriptor->Get(context, v8_str(isolate, "element"));
+    v8::Local<v8::Value> value;
+    if (!maybe.ToLocal(&value)) return;
+    v8::Local<v8::String> string;
+    if (!value->ToString(context).ToLocal(&string)) return;
+    bool equal;
+    if (!string->Equals(context, v8_str(isolate, "anyfunc")).To(&equal)) return;
+    if (!equal) {
+      thrower.TypeError("Descriptor property 'element' must be 'anyfunc'");
+      return;
+    }
+  }
+  // The descriptor's 'initial'.
+  int initial;
+  {
+    v8::MaybeLocal<v8::Value> maybe =
+        descriptor->Get(context, v8_str(isolate, "initial"));
+    v8::Local<v8::Value> value;
+    if (!maybe.ToLocal(&value)) return;
+    int64_t number;

[titzer, 2016/09/20 12:37:21]

Can we factor out a helper routine for setting a numeric property on an object?
Basically the int64_t / IntegerValue / positive check here and below? If you
make it take an expected range (i.e. minimum legal value, maximum legal value),
then you can use it below, too.

[ahaas, 2016/09/21 09:38:11]

Done.

+    if (!value->IntegerValue(context).To(&number)) return;
+    if (number < 0) {
+      thrower.RangeError("Descriptor property 'initial' must not be negative");
+      return;
+    }
+    initial = static_cast<int>(number);
+    if (initial != number) {
+      thrower.RangeError("Descriptor property 'initial' too large");
+      return;
+    }
+  }
+  // The descriptor's 'maximum'.
+  Maybe<int> maximum = Nothing<int>();
+  {
+    v8::MaybeLocal<v8::Value> maybe =
+        descriptor->Get(context, v8_str(isolate, "maximum"));
+    v8::Local<v8::Value> value;
+    if (maybe.ToLocal(&value) && !value->IsUndefined()) {
+      int64_t number;
+      if (!value->IntegerValue(context).To(&number)) return;
+      if (number < 0) {
+        thrower.RangeError(
+            "Descriptor property 'maximum' must not be negative");
+        return;
+      }
+      int num = static_cast<int>(number);
+      if (num != number) {
+        thrower.RangeError("Descriptor property 'maximum' too large");
+        return;
+      }
+      if (num < initial) {
+        thrower.RangeError(
+            "Descriptor property 'maximum' must not be smaller than 'initial'");
+        return;
+      }
+      maximum = Just(num);
+    }
+  }
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  i::Handle<i::JSFunction> table_cons(
+      i_isolate->native_context()->wasm_table_constructor());
+  i::Handle<i::JSObject> table_obj =
+      i_isolate->factory()->NewJSObject(table_cons);
+  i::Handle<i::FixedArray> fixed_array =
+      i_isolate->factory()->NewFixedArray(initial);
+  i::Object* null = i_isolate->heap()->null_value();
+  for (int i = 0; i < initial; ++i) fixed_array->set(i, null);
+  table_obj->SetInternalField(0, *fixed_array);
+  table_obj->SetInternalField(
+      1, maximum.IsNothing()
+             ? static_cast<i::Object*>(i_isolate->heap()->undefined_value())
+             : static_cast<i::Object*>(i::Smi::FromInt(maximum.ToChecked())));
+  i::Handle<i::Symbol> table_sym(i_isolate->native_context()->wasm_table_sym());
+  i::Object::SetProperty(table_obj, table_sym, table_obj, i::STRICT).Check();
+  v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
+  return_value.Set(Utils::ToLocal(table_obj));
+}
+void WebAssemblyMemory(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  v8::Isolate* isolate = args.GetIsolate();
+  HandleScope scope(isolate);
+  ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
+                       "WebAssembly.Module()");
+  if (args.Length() < 1 || !args[0]->IsObject()) {
+    thrower.TypeError("Argument 0 must be a table descriptor");
+    return;
+  }
+  Local<Context> context = isolate->GetCurrentContext();
+  Local<v8::Object> descriptor = args[0]->ToObject(context).ToLocalChecked();
+  // The descriptor's 'initial'.
+  int initial;
+  {
+    v8::MaybeLocal<v8::Value> maybe =
+        descriptor->Get(context, v8_str(isolate, "initial"));
+    v8::Local<v8::Value> value;
+    if (!maybe.ToLocal(&value)) return;
+    int64_t number;
+    if (!value->IntegerValue(context).To(&number)) return;
+    if (number < 0) {
+      thrower.RangeError("Descriptor property 'inital' must not be negative");
+      return;
+    }
+    initial = static_cast<int>(number);
+    if (initial != number || initial > 65536) {
+      thrower.RangeError(
+          "Descriptor property 'initial' "
+          "must not be larger than 65536 (4GiB)");
+      return;
+    }
+  }
+  // The descriptor's 'maximum'.
+  Maybe<int> maximum = Nothing<int>();
+  {
+    v8::MaybeLocal<v8::Value> maybe =
+        descriptor->Get(context, v8_str(isolate, "maximum"));
+    v8::Local<v8::Value> value;
+    if (maybe.ToLocal(&value) && !value->IsUndefined()) {
+      int64_t number;
+      if (!value->IntegerValue(context).To(&number)) return;
+      if (number < 0) {
+        thrower.RangeError(
+            "Descriptor property 'maximum' must not be negative");
+        return;
+      }
+      int num = static_cast<int>(number);
+      if (num != number || initial > 65536) {
+        thrower.RangeError(
+            "Descriptor property 'maximum' must not be larger than 65536 "
+            "(4GiB)");
+        return;
+      }
+      if (num < initial) {
+        thrower.RangeError(
+            "Descriptor property 'maximum' must not be smaller than 'initial'");
+        return;
+      }
+      maximum = Just(num);
+    }
+  }
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  i::Handle<i::JSFunction> memory_cons(
+      i_isolate->native_context()->wasm_memory_constructor());
+  i::Handle<i::JSObject> memory_obj =
+      i_isolate->factory()->NewJSObject(memory_cons);
+  i::Handle<i::JSArrayBuffer> buffer =
+      i_isolate->factory()->NewJSArrayBuffer(i::SharedFlag::kNotShared);
+  size_t size = static_cast<size_t>(i::wasm::WasmModule::kPageSize) *
+                static_cast<size_t>(initial);
+  i::JSArrayBuffer::SetupAllocatingData(buffer, i_isolate, size);
+  memory_obj->SetInternalField(0, *buffer);
+  memory_obj->SetInternalField(
+      1, maximum.IsNothing()
+             ? static_cast<i::Object*>(i_isolate->heap()->undefined_value())
+             : static_cast<i::Object*>(i::Smi::FromInt(maximum.ToChecked())));
+  i::Handle<i::Symbol> memory_sym(
+      i_isolate->native_context()->wasm_memory_sym());
+  i::Object::SetProperty(memory_obj, memory_sym, memory_obj, i::STRICT).Check();
+  v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
+  return_value.Set(Utils::ToLocal(memory_obj));
+}
+void WebAssemblyTableGetLength(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  // TODO(rossberg)
+}
+void WebAssemblyTableGrow(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  // TODO(rossberg)
+}
+void WebAssemblyTableGet(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  // TODO(rossberg)
+}
+void WebAssemblyTableSet(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  // TODO(rossberg)
+}
+void WebAssemblyMemoryGrow(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  // TODO(rossberg)
+}
+void WebAssemblyMemoryGetBuffer(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  v8::Isolate* isolate = args.GetIsolate();
+  Local<Context> context = isolate->GetCurrentContext();
+  i::Handle<i::Context> i_context = Utils::OpenHandle(*context);
+  if (!BrandCheck(isolate, Utils::OpenHandle(*args.This()),
+                  i::Handle<i::Symbol>(i_context->wasm_memory_sym()),
+                  "Receiver is not a WebAssembly.Memory")) {
+    return;
+  }
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  i::Handle<i::JSObject> receiver =
+      i::Handle<i::JSObject>::cast(Utils::OpenHandle(*args.This()));
+  i::Handle<i::Object> buffer(receiver->GetInternalField(0), i_isolate);
+  DCHECK(buffer->IsJSArrayBuffer());
+  v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
+  return_value.Set(Utils::ToLocal(buffer));
+}
 }  // namespace
 
 // TODO(titzer): we use the API to create the function template because the
 // internal guts are too ugly to replicate here.
 static i::Handle<i::FunctionTemplateInfo> NewTemplate(i::Isolate* i_isolate,
                                                       FunctionCallback func) {
   Isolate* isolate = reinterpret_cast<Isolate*>(i_isolate);
   Local<FunctionTemplate> local = FunctionTemplate::New(isolate, func);
   return v8::Utils::OpenHandle(*local);
 }
 
 namespace internal {
-static Handle<String> v8_str(Isolate* isolate, const char* str) {
-  return isolate->factory()->NewStringFromAsciiChecked(str);
-}
 
-static Handle<JSFunction> InstallFunc(Isolate* isolate, Handle<JSObject> object,
-                                      const char* str, FunctionCallback func) {
+Handle<JSFunction> InstallFunc(Isolate* isolate, Handle<JSObject> object,
+                               const char* str, FunctionCallback func) {
   Handle<String> name = v8_str(isolate, str);
   Handle<FunctionTemplateInfo> temp = NewTemplate(isolate, func);
   Handle<JSFunction> function =
       ApiNatives::InstantiateFunction(temp).ToHandleChecked();
   PropertyAttributes attributes =
       static_cast<PropertyAttributes>(DONT_DELETE | READ_ONLY);
   JSObject::AddProperty(object, name, function, attributes);
   return function;
 }
 
+Handle<JSFunction> InstallGetter(Isolate* isolate, Handle<JSObject> object,
+                                 const char* str, FunctionCallback func) {
+  Handle<String> name = v8_str(isolate, str);
+  Handle<FunctionTemplateInfo> temp = NewTemplate(isolate, func);
+  Handle<JSFunction> function =
+      ApiNatives::InstantiateFunction(temp).ToHandleChecked();
+  v8::PropertyAttribute attributes =
+      static_cast<v8::PropertyAttribute>(v8::DontDelete | v8::ReadOnly);
+  Utils::ToLocal(object)->SetAccessorProperty(Utils::ToLocal(name),
+                                              Utils::ToLocal(function),
+                                              Local<Function>(), attributes);
+  return function;
+}
+
 void WasmJs::InstallWasmModuleSymbolIfNeeded(Isolate* isolate,
                                              Handle<JSGlobalObject> global,
                                              Handle<Context> context) {
   if (!context->get(Context::WASM_MODULE_SYM_INDEX)->IsSymbol() ||
       !context->get(Context::WASM_INSTANCE_SYM_INDEX)->IsSymbol()) {
-    Factory* factory = isolate->factory();
-    // Create private symbols.
-    Handle<Symbol> module_sym = factory->NewPrivateSymbol();
-    Handle<Symbol> instance_sym = factory->NewPrivateSymbol();
-    context->set_wasm_module_sym(*module_sym);
-    context->set_wasm_instance_sym(*instance_sym);
+    InstallWasmMapsIfNeeded(isolate, isolate->native_context());
+    InstallWasmConstructors(isolate, isolate->global_object(),
+                            isolate->native_context());
+  }
+}
 
-    // Bind the WebAssembly object.
-    Handle<String> name = v8_str(isolate, "WebAssembly");
-    Handle<JSFunction> cons = factory->NewFunction(name);
-    JSFunction::SetInstancePrototype(
-        cons, Handle<Object>(context->initial_object_prototype(), isolate));
-    cons->shared()->set_instance_class_name(*name);
-    Handle<JSObject> wasm_object = factory->NewJSObject(cons, TENURED);
-    PropertyAttributes attributes = static_cast<PropertyAttributes>(DONT_ENUM);
-    JSObject::AddProperty(global, name, wasm_object, attributes);
-
-    // Install static methods on WebAssembly object.
-    InstallFunc(isolate, wasm_object, "compile", WebAssemblyCompile);
-    Handle<JSFunction> module_constructor =
-        InstallFunc(isolate, wasm_object, "Module", WebAssemblyModule);
-    Handle<JSFunction> instance_constructor =
-        InstallFunc(isolate, wasm_object, "Instance", WebAssemblyInstance);
-    i::Handle<i::Map> map = isolate->factory()->NewMap(
-        i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize + i::kPointerSize);
-    module_constructor->set_prototype_or_initial_map(*map);
-    map->SetConstructor(*module_constructor);
-
-    context->set_wasm_module_constructor(*module_constructor);
-    context->set_wasm_instance_constructor(*instance_constructor);
-  }
+void WasmJs::InstallWasmConstructors(Isolate* isolate,
+                                     Handle<JSGlobalObject> global,
+                                     Handle<Context> context) {
+  Factory* factory = isolate->factory();
+  // Create private symbols.
+  Handle<Symbol> module_sym = factory->NewPrivateSymbol();
+  Handle<Symbol> instance_sym = factory->NewPrivateSymbol();
+  Handle<Symbol> table_sym = factory->NewPrivateSymbol();
+  Handle<Symbol> memory_sym = factory->NewPrivateSymbol();
+  context->set_wasm_module_sym(*module_sym);
+  context->set_wasm_instance_sym(*instance_sym);
+  context->set_wasm_table_sym(*table_sym);
+  context->set_wasm_memory_sym(*memory_sym);
+  // Bind the WebAssembly object.
+  Handle<String> name = v8_str(isolate, "WebAssembly");
+  Handle<JSFunction> cons = factory->NewFunction(name);
+  JSFunction::SetInstancePrototype(
+      cons, Handle<Object>(context->initial_object_prototype(), isolate));
+  cons->shared()->set_instance_class_name(*name);
+  Handle<JSObject> wasm_object = factory->NewJSObject(cons, TENURED);
+  PropertyAttributes attributes = static_cast<PropertyAttributes>(DONT_ENUM);
+  JSObject::AddProperty(global, name, wasm_object, attributes);
+  // Install static methods on WebAssembly object.
+  InstallFunc(isolate, wasm_object, "compile", WebAssemblyCompile);
+  Handle<JSFunction> module_constructor =

[titzer, 2016/09/20 12:37:21]

It's tough to see what's going in here exactly, but is it possible to factor out
a subroutine that creates the constructor and the prototype and the map
together?

[ahaas, 2016/09/21 09:38:11]

I restructured code now, but I don't think that it's worth factoring out
subroutines. Especially functions like
context->set_wasm_module_constructor(*module_constructor); and
context->set_wasm_instance_constructor(*instance_constructor);
are problematic.

[titzer, 2016/09/21 09:47:44]

Ok, we can always take another crack at it later.

+      InstallFunc(isolate, wasm_object, "Module", WebAssemblyModule);
+  Handle<JSFunction> instance_constructor =
+      InstallFunc(isolate, wasm_object, "Instance", WebAssemblyInstance);
+  Handle<JSFunction> table_constructor =
+      InstallFunc(isolate, wasm_object, "Table", WebAssemblyTable);
+  Handle<JSFunction> memory_constructor =
+      InstallFunc(isolate, wasm_object, "Memory", WebAssemblyMemory);
+  context->set_wasm_module_constructor(*module_constructor);
+  context->set_wasm_instance_constructor(*instance_constructor);
+  context->set_wasm_table_constructor(*table_constructor);
+  context->set_wasm_memory_constructor(*memory_constructor);
+  // Set up prototypes and instance maps.
+  Handle<JSObject> module_proto =
+      factory->NewJSObject(module_constructor, TENURED);
+  i::Handle<i::Map> map = isolate->factory()->NewMap(
+      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize + i::kPointerSize);
+  JSFunction::SetInitialMap(module_constructor, map, module_proto);
+  Handle<JSObject> table_proto =
+      factory->NewJSObject(table_constructor, TENURED);
+  map = isolate->factory()->NewMap(
+      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize + 2 * i::kPointerSize);
+  JSFunction::SetInitialMap(table_constructor, map, table_proto);
+  Handle<JSObject> memory_proto =
+      factory->NewJSObject(memory_constructor, TENURED);
+  map = isolate->factory()->NewMap(
+      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize + 2 * i::kPointerSize);
+  JSFunction::SetInitialMap(memory_constructor, map, memory_proto);
+  // Add prototype properties.
+  JSObject::AddProperty(module_proto, isolate->factory()->constructor_string(),
+                        module_constructor, DONT_ENUM);
+  JSObject::AddProperty(table_proto, isolate->factory()->constructor_string(),
+                        table_constructor, DONT_ENUM);
+  InstallGetter(isolate, table_proto, "length", WebAssemblyTableGetLength);
+  InstallFunc(isolate, table_proto, "grow", WebAssemblyTableGrow);
+  InstallFunc(isolate, table_proto, "get", WebAssemblyTableGet);
+  InstallFunc(isolate, table_proto, "set", WebAssemblyTableSet);
+  JSObject::AddProperty(memory_proto, isolate->factory()->constructor_string(),
+                        memory_constructor, DONT_ENUM);
+  InstallFunc(isolate, memory_proto, "grow", WebAssemblyMemoryGrow);
+  InstallGetter(isolate, memory_proto, "buffer", WebAssemblyMemoryGetBuffer);
 }
 
 void WasmJs::Install(Isolate* isolate, Handle<JSGlobalObject> global) {
   if (!FLAG_expose_wasm && !FLAG_validate_asm) {
     return;
   }
 
   Factory* factory = isolate->factory();
 
   // Setup wasm function map.
   Handle<Context> context(global->native_context(), isolate);
-  InstallWasmFunctionMapIfNeeded(isolate, context);
+  InstallWasmMapsIfNeeded(isolate, context);
 
   if (!FLAG_expose_wasm) {
     return;
   }
 
   // Bind the experimental WASM object.
   // TODO(rossberg, titzer): remove once it's no longer needed.
   {
     Handle<String> name = v8_str(isolate, "Wasm");
     Handle<JSFunction> cons = factory->NewFunction(name);
@@ skipping 12 matching lines @@
     {
       // Add the Wasm.experimentalVersion property.
       Handle<String> name = v8_str(isolate, "experimentalVersion");
       PropertyAttributes attributes =
           static_cast<PropertyAttributes>(DONT_DELETE | READ_ONLY);
       Handle<Smi> value =
           Handle<Smi>(Smi::FromInt(wasm::kWasmVersion), isolate);
       JSObject::AddProperty(wasm_object, name, value, attributes);
     }
   }
-  InstallWasmModuleSymbolIfNeeded(isolate, global, context);
+  InstallWasmConstructors(isolate, global, context);
 }
 
-void WasmJs::InstallWasmFunctionMapIfNeeded(Isolate* isolate,
-                                            Handle<Context> context) {
+void WasmJs::InstallWasmMapsIfNeeded(Isolate* isolate,
+                                     Handle<Context> context) {
   if (!context->get(Context::WASM_FUNCTION_MAP_INDEX)->IsMap()) {
     // TODO(titzer): Move this to bootstrapper.cc??
     // TODO(titzer): Also make one for strict mode functions?
     Handle<Map> prev_map = Handle<Map>(context->sloppy_function_map(), isolate);
 
     InstanceType instance_type = prev_map->instance_type();
     int internal_fields = JSObject::GetInternalFieldCount(*prev_map);
     CHECK_EQ(0, internal_fields);
     int pre_allocated =
         prev_map->GetInObjectProperties() - prev_map->unused_property_fields();
     int instance_size = 0;
     int in_object_properties = 0;
     int wasm_internal_fields = internal_fields + 1  // module instance object
                                + 1                  // function arity
                                + 1;                 // function signature
     JSFunction::CalculateInstanceSizeHelper(instance_type, wasm_internal_fields,
                                             0, &instance_size,
                                             &in_object_properties);
 
     int unused_property_fields = in_object_properties - pre_allocated;
     Handle<Map> map = Map::CopyInitialMap(
         prev_map, instance_size, in_object_properties, unused_property_fields);
 
     context->set_wasm_function_map(*map);
   }
 }
 
 }  // namespace internal
 }  // namespace v8