[wasm] Add guard regions to end of WebAssembly.Memory buffers

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 210 matching lines @@
   i::Handle<i::JSObject> i_obj =
       i::Handle<i::JSObject>::cast(v8::Utils::OpenHandle(*obj));
 
   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()) {
+  if (args.Length() > 2 && args[2]->IsObject()) {

[Mircea Trofin, 2016/10/28 22:16:29]

please separate support for WebAssembly.Memory in a different CL.

[Eric Holk, 2016/10/29 00:04:30]

Done: https://codereview.chromium.org/2460773003/

     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));
+    if (i::WasmJs::IsWasmMemoryObject(i_isolate, mem_obj)) {
+      memory = i::WasmJs::GetWasmMemoryArrayBuffer(i_isolate, mem_obj);

[titzer, 2016/10/28 16:24:57]

Can we split out the WebAssembly.Memory requirement (and changes to tests) into
another CL? That'd be easy to land first.

[Eric Holk, 2016/10/28 18:44:40]

Sure. I'll add a couple more cases to make sure we fail correctly when using a
non-WebAssembly.Memory object.

https://codereview.chromium.org/2460773003

+    }
   }
   i::MaybeHandle<i::JSObject> instance =
       i::wasm::WasmModule::Instantiate(i_isolate, &thrower, i_obj, ffi, memory);
   if (instance.is_null()) {
     if (!thrower.error()) thrower.RuntimeError("Could not instantiate module");
     return;
   }
   DCHECK(!i_isolate->has_pending_exception());
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(Utils::ToLocal(instance.ToHandleChecked()));
@@ skipping 111 matching lines @@
     // There has been an exception, just return.
     return;
   }
   if (has_maximum.FromJust()) {
     if (!GetIntegerProperty(isolate, &thrower, context, descriptor, maximum_key,
                             &maximum, initial, 65536)) {
       return;
     }
   }
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  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);
+  i::Handle<i::JSArrayBuffer> buffer =
+      i::wasm::NewArrayBuffer(i_isolate, size, i::FLAG_wasm_guard_pages);
 
   i::Handle<i::JSObject> memory_obj = i::WasmJs::CreateWasmMemoryObject(
       i_isolate, buffer, has_maximum.FromJust(), maximum);
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(Utils::ToLocal(memory_obj));
 }
 
 void WebAssemblyTableGetLength(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
@@ skipping 473 matching lines @@
   if (!memory_object->IsUndefined(isolate)) {
     DCHECK(IsWasmMemoryObject(isolate, memory_object));
     // TODO(gdeepti): This should be a weak list of instance objects
     // for instances that share memory.
     JSObject::cast(*memory_object)
         ->SetInternalField(kWasmMemoryInstanceObject, *instance);
   }
 }
 }  // namespace internal
 }  // namespace v8