[wasm] allow WebAssembly memory to instantiated as a SharedArrayBuffer

By recognizing a new boolean field in the options object passed to WebAssembly.Memory: isShared.
bpowers · Jan 13, 2017 · bda41b7 · bda41b7
1 parent ad889a6
commit bda41b7
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Showing 3 changed files with 29 additions and 4 deletions.
diff --git a/src/wasm/wasm-js.cc b/src/wasm/wasm-js.cc
@@ -359,6 +359,7 @@ void WebAssemblyInstantiate(const v8::FunctionCallbackInfo<v8::Value>& args) {
   return_value.Set(resolver->GetPromise());
 }
 
+static
 bool GetIntegerProperty(v8::Isolate* isolate, ErrorThrower* thrower,
                         Local<Context> context, Local<v8::Object> object,
                         Local<String> property, int* result, int lower_bound,
@@ -386,6 +387,22 @@ bool GetIntegerProperty(v8::Isolate* isolate, ErrorThrower* thrower,
   return false;
 }
 
+static
+bool GetBooleanProperty(v8::Isolate* isolate, ErrorThrower* thrower,
+                        Local<Context> context, Local<v8::Object> object,
+                        Local<String> property, bool* result, bool default_=false) {
+  v8::MaybeLocal<v8::Value> maybe = object->Get(context, property);
+  v8::Local<v8::Value> value;
+  if (maybe.ToLocal(&value)) {
+    bool boolean;
+    if (!value->BooleanValue(context).To(&boolean)) return false;
+    *result = boolean;
+    return true;
+  }
+  *result = default_;
+  return true;
+}
+
 const int max_table_size = 1 << 26;
 
 void WebAssemblyTable(const v8::FunctionCallbackInfo<v8::Value>& args) {
@@ -479,11 +496,17 @@ void WebAssemblyMemory(const v8::FunctionCallbackInfo<v8::Value>& args) {
       return;
     }
   }
+  bool is_shared = false;
+  if (!GetBooleanProperty(isolate, &thrower, context, descriptor,
+			  v8_str(isolate, "isShared"), &is_shared)) {
+	  return;
+  }
+  auto shared = is_shared ? i::SharedFlag::kShared : i::SharedFlag::kNotShared;
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   size_t size = static_cast<size_t>(i::wasm::WasmModule::kPageSize) *
                 static_cast<size_t>(initial);
   i::Handle<i::JSArrayBuffer> buffer =
-      i::wasm::NewArrayBuffer(i_isolate, size, i::FLAG_wasm_guard_pages);
+      i::wasm::NewArrayBuffer(i_isolate, size, i::FLAG_wasm_guard_pages, shared);
   if (buffer.is_null()) {
     thrower.RangeError("could not allocate memory");
     return;

diff --git a/src/wasm/wasm-module.cc b/src/wasm/wasm-module.cc
@@ -784,7 +784,8 @@ Handle<Script> CreateWasmScript(Isolate* isolate,
 }  // namespace
 
 Handle<JSArrayBuffer> wasm::NewArrayBuffer(Isolate* isolate, size_t size,
-                                           bool enable_guard_regions) {
+                                           bool enable_guard_regions,
+                                           SharedFlag shared) {
   if (size > (kV8MaxWasmMemoryPages * WasmModule::kPageSize)) {
     // TODO(titzer): lift restriction on maximum memory allocated here.
     return Handle<JSArrayBuffer>::null();
@@ -810,7 +811,7 @@ Handle<JSArrayBuffer> wasm::NewArrayBuffer(Isolate* isolate, size_t size,
 
   Handle<JSArrayBuffer> buffer = isolate->factory()->NewJSArrayBuffer();
   JSArrayBuffer::Setup(buffer, isolate, is_external, memory,
-                       static_cast<int>(size));
+                       static_cast<int>(size), shared);
   buffer->set_is_neuterable(false);
   buffer->set_has_guard_region(enable_guard_regions);
 

diff --git a/src/wasm/wasm-module.h b/src/wasm/wasm-module.h
@@ -426,7 +426,8 @@ int32_t GrowInstanceMemory(Isolate* isolate,
                            Handle<WasmInstanceObject> instance, uint32_t pages);
 
 Handle<JSArrayBuffer> NewArrayBuffer(Isolate* isolate, size_t size,
-                                     bool enable_guard_regions);
+                                     bool enable_guard_regions,
+                                     SharedFlag shared = SharedFlag::kNotShared);
 
 int32_t GrowWebAssemblyMemory(Isolate* isolate, Handle<Object> receiver,
                               uint32_t pages);