[wasm] WebAssembly.instantiate has a pair-returning overload

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 50 matching lines @@
     Local<TypedArray> array = Local<TypedArray>::Cast(source);
     Local<ArrayBuffer> buffer = array->Buffer();
 
     ArrayBuffer::Contents contents = buffer->GetContents();
 
     start =
         reinterpret_cast<const byte*>(contents.Data()) + array->ByteOffset();
     end = start + array->ByteLength();
 
   } else {
-    thrower->TypeError("Argument 0 must be an ArrayBuffer or Uint8Array");
+    thrower->TypeError("Argument 0 must be a buffer source");
   }
   if (start == nullptr || end == start) {
     thrower->CompileError("BufferSource argument is empty");
   }
   return {start, end};
 }
 
 static i::MaybeHandle<i::WasmModuleObject> CreateModuleObject(
     v8::Isolate* isolate, const v8::Local<v8::Value> source,
     ErrorThrower* thrower) {
@@ skipping 17 matching lines @@
 
   RawBuffer buffer = GetRawBufferSource(source, thrower);
   if (buffer.start == nullptr) return false;
 
   DCHECK(source->IsArrayBuffer() || source->IsTypedArray());
   return i::wasm::ValidateModuleBytes(i_isolate, buffer.start, buffer.end,
                                       thrower,
                                       i::wasm::ModuleOrigin::kWasmOrigin);
 }
 
+// TODO(wasm): move brand check to the respective types, and don't throw
+// in it, rather, use a provided ErrorThrower, or let caller handle it.
+static bool BrandCheck(Isolate* isolate, i::Handle<i::Object> value,
+                       i::Handle<i::Symbol> sym) {
+  if (!value->IsJSObject()) return false;
+  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;
+  return has_brand.ToChecked();
+}
+
 static 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);
@@ skipping 43 matching lines @@
     return_value.Set(v8::False(isolate));
   }
 }
 
 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) {
+  if (args.Length() != 1) {

[rossberg, 2017/01/20 09:56:54]

JavaScript always allows unused extra arguments, so this actually is incorrect
(and was before). Just leave the condition as is and delete the other `if`.

[Mircea Trofin, 2017/01/20 16:29:53]

Done.

     thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
 
-  if (args.Length() > 2) {
-    thrower.LinkError(
-        "WebAssembly.instantiate accepts no more than 2 parameters");
-    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()));
 }
 
 MaybeLocal<Value> InstantiateModuleImpl(
     i::Isolate* i_isolate, i::Handle<i::WasmModuleObject> i_module_obj,
@@ skipping 126 matching lines @@
 }
 
 void WebAssemblyInstantiate(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
 
   HandleScope scope(isolate);
   ErrorThrower thrower(i_isolate, "WebAssembly.compile()");
 
   Local<Context> context = isolate->GetCurrentContext();
+  i::Handle<i::Context> i_context = Utils::OpenHandle(*context);
+
   v8::Local<v8::Promise::Resolver> resolver;
   if (!v8::Promise::Resolver::New(context).ToLocal(&resolver)) return;
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(resolver->GetPromise());
 
   if (args.Length() < 1) {
-    thrower.TypeError("Argument 0 must be a buffer source");
+    thrower.TypeError(
+        "Argument 0 must be provided and must be either a buffer source or a "
+        "WebAssembly.Module object");
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
     return;
   }
 
-  i::MaybeHandle<i::WasmModuleObject> module_obj =
-      CreateModuleObject(isolate, args[0], &thrower);
-  if (module_obj.is_null()) {
-    DCHECK(thrower.error());
+  i::Handle<i::Object> first_arg = Utils::OpenHandle(*args[0]);
+  if (!first_arg->IsJSObject()) {
+    thrower.TypeError(
+        "Argument 0 must be a buffer source or a WebAssembly.Module object");
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
     return;
   }
-
-  MaybeLocal<Value> instance = InstantiateModuleImpl(
-      i_isolate, module_obj.ToHandleChecked(), args, &thrower);
+  bool want_pair = !BrandCheck(
+      isolate, first_arg, i::Handle<i::Symbol>(i_context->wasm_module_sym()));
+  i::Handle<i::WasmModuleObject> module_obj;
+  if (want_pair) {
+    i::MaybeHandle<i::WasmModuleObject> maybe_module_obj =
+        CreateModuleObject(isolate, args[0], &thrower);
+    if (!maybe_module_obj.ToHandle(&module_obj)) {
+      DCHECK(thrower.error());
+      resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+      return;
+    }
+  } else {
+    module_obj = i::Handle<i::WasmModuleObject>::cast(first_arg);
+  }
+  DCHECK(!module_obj.is_null());
+  MaybeLocal<Value> instance =
+      InstantiateModuleImpl(i_isolate, module_obj, args, &thrower);
   if (instance.IsEmpty()) {
     DCHECK(thrower.error());
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
   } else {
     DCHECK(!thrower.error());
-    resolver->Resolve(context, instance.ToLocalChecked());
+    Local<Value> retval;
+    if (want_pair) {
+      i::Handle<i::JSFunction> object_function = i::Handle<i::JSFunction>(
+          i_isolate->native_context()->object_function(), i_isolate);
+
+      i::Handle<i::JSObject> i_retval =
+          i_isolate->factory()->NewJSObject(object_function, i::TENURED);
+      i::Handle<i::String> module_property_name =
+          i_isolate->factory()->InternalizeUtf8String("module");
+      i::Handle<i::String> instance_property_name =
+          i_isolate->factory()->InternalizeUtf8String("instance");
+      i::JSObject::AddProperty(i_retval, module_property_name, module_obj,
+                               i::NONE);
+      i::JSObject::AddProperty(i_retval, instance_property_name,
+                               Utils::OpenHandle(*instance.ToLocalChecked()),
+                               i::NONE);
+      retval = Utils::ToLocal(i_retval);
+    } else {
+      retval = instance.ToLocalChecked();
+    }
+    DCHECK(!retval.IsEmpty());
+    resolver->Resolve(context, retval);
   }
 }
 
 bool GetIntegerProperty(v8::Isolate* isolate, ErrorThrower* thrower,
                         Local<Context> context, Local<v8::Object> object,
                         Local<String> property, int* result,
                         int64_t lower_bound, uint64_t upper_bound) {
   v8::MaybeLocal<v8::Value> maybe = object->Get(context, property);
   v8::Local<v8::Value> value;
   if (maybe.ToLocal(&value)) {
@@ skipping 538 matching lines @@
   i::Handle<i::Symbol> symbol(isolate->context()->wasm_memory_sym(), isolate);
   return HasBrand(value, symbol);
 }
 
 bool WasmJs::IsWasmTableObject(Isolate* isolate, Handle<Object> value) {
   i::Handle<i::Symbol> symbol(isolate->context()->wasm_table_sym(), isolate);
   return HasBrand(value, symbol);
 }
 }  // namespace internal
 }  // namespace v8