[wasm] GrowMemory should use maximum size declared in WebAssembly.Memory

src/wasm/wasm-js.cc

Index: src/wasm/wasm-js.cc
diff --git a/src/wasm/wasm-js.cc b/src/wasm/wasm-js.cc
index 57ee2654f9981e96d4b9a513d09689f5c60f590d..bd71f619fa8fc058c5a411817eaedab51c387234 100644
--- a/src/wasm/wasm-js.cc
+++ b/src/wasm/wasm-js.cc
@@ -496,7 +496,39 @@ void WebAssemblyTableSet(const v8::FunctionCallbackInfo<v8::Value>& args) {
   // TODO(rossberg)
 }
 void WebAssemblyMemoryGrow(const v8::FunctionCallbackInfo<v8::Value>& args) {
-  // TODO(rossberg)
+  v8::Isolate* isolate = args.GetIsolate();
+  HandleScope scope(isolate);
+  ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
+                       "WebAssembly.Memory()");
+  if (args.Length() < 1 || !args[0]->IsUint32()) {
+    thrower.RangeError("Argument 0 must be numeric value of pages");
+    return;
+  }
+
+  Local<Context> context = isolate->GetCurrentContext();
+  uint32_t delta = args[0]->Uint32Value(context).FromJust();
+  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 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> instance_object(receiver->GetInternalField(2),
+                                       i_isolate);
+
+  // TODO(gdeepti) Implement growing memory when shared by different
+  // instances.
+  uint32_t ret = internal::wasm::GrowInstanceMemory(
+      i_isolate, i::Handle<i::JSObject>::cast(instance_object), delta);
+  if (ret == -1) {
+    thrower.Error("Error while growing memory");
+  }
+
+  v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
+  return_value.Set(ret);
 }
 void WebAssemblyMemoryGetBuffer(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
@@ -658,7 +690,7 @@ void WasmJs::InstallWasmConstructors(Isolate* isolate,
   Handle<JSObject> memory_proto =
       factory->NewJSObject(memory_constructor, TENURED);
   map = isolate->factory()->NewMap(
-      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize + 2 * i::kPointerSize);
+      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize + 3 * i::kPointerSize);
   JSFunction::SetInitialMap(memory_constructor, map, memory_proto);
   JSObject::AddProperty(memory_proto, isolate->factory()->constructor_string(),
                         memory_constructor, DONT_ENUM);