Migrate %TypedArray%.prototype.fill to C++

src/elements.cc

Index: src/elements.cc
diff --git a/src/elements.cc b/src/elements.cc
index 7b7f6893d84b557224acb1232b7798eb39cbb461..2e1bc5fbb8c111e1bbbe8ae78488f206d9840ce2 100644
--- a/src/elements.cc
+++ b/src/elements.cc
@@ -470,6 +470,28 @@ static void SortIndices(
   }
 }
 
+static Object* FillNumberSlowPath(Isolate* isolate, Handle<JSTypedArray> array,
+                               Handle<Object> obj_value,
+                               uint32_t start, uint32_t end) {
+  const char* kMethodName = "%TypedArray%.prototype.fill";
+  Handle<Object> cast_value;
+  ElementsAccessor* elements = array->GetElementsAccessor();
+
+  for (uint32_t k = start; k < end; ++k) {
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, cast_value, Object::ToNumber(obj_value));
+    // TODO(caitp,cbruni): throw on neutered array and just return *array

[Camillo Bruni, 2017/03/13 09:02:30]

drop "and just return *array"

[rongjie, 2017/03/13 10:46:40]

Done.

+    if (V8_UNLIKELY(array->WasNeutered())) {
+      THROW_NEW_ERROR_RETURN_FAILURE(
+          isolate, NewTypeError(MessageTemplate::kDetachedOperation,
+                                isolate->factory()->NewStringFromAsciiChecked(
+                                kMethodName)));

[Camillo Bruni, 2017/03/13 09:02:30]

sorry, my comment wasn't clear enough :P, we don't throw for now (see other
places with checks for WasNeutered)...

return *array

[rongjie, 2017/03/13 10:46:40]

Done.

+    }
+    elements->Set(array, k, *cast_value);
+  }
+  return *array;
+}
+
 static Maybe<bool> IncludesValueSlowPath(Isolate* isolate,
                                          Handle<JSObject> receiver,
                                          Handle<Object> value,
@@ -1191,6 +1213,17 @@ class ElementsAccessorBase : public ElementsAccessor {
     return Subclass::GetCapacityImpl(holder, backing_store);
   }
 
+  static Object* FillImpl(Isolate* isolate, Handle<JSObject> receiver,
+                       Handle<Object> obj_value, uint32_t start, uint32_t end) {
+    UNREACHABLE();
+    return *receiver;
+  }
+
+  Object* Fill(Isolate* isolate, Handle<JSObject> receiver,
+            Handle<Object> obj_value, uint32_t start, uint32_t end) {
+    return Subclass::FillImpl(isolate, receiver, obj_value, start, end);
+  }
+
   static Maybe<bool> IncludesValueImpl(Isolate* isolate,
                                        Handle<JSObject> receiver,
                                        Handle<Object> value,
@@ -2815,6 +2848,38 @@ class TypedElementsAccessor
     return Just(true);
   }
 
+  static Object* FillImpl(Isolate* isolate, Handle<JSObject> receiver,
+                       Handle<Object> obj_value, uint32_t start, uint32_t end) {
+    Handle<JSTypedArray> array = Handle<JSTypedArray>::cast(receiver);
+
+    if (!obj_value->IsNumber()) {
+      return FillNumberSlowPath(isolate, array, obj_value, start, end);
+    }
+
+    ctype value = 0;
+
+    if (obj_value->IsSmi()) {
+      value = static_cast<ctype>(Smi::cast(*obj_value)->value());
+    } else {
+      DCHECK(obj_value->IsHeapNumber());
+      value = static_cast<ctype>(HeapNumber::cast(*obj_value)->value());
+    }
+    if (array->type() == kExternalUint8ClampedArray) {
+      value = std::min<ctype>(std::max<ctype>(0, value), 255);
+    }
+
+    // Ensure indexes are within array bounds
+    DCHECK_LE(0, start);
+    DCHECK_LE(start, end);
+    DCHECK_LE(end, array->length_value());
+
+    Handle<FixedTypedArrayBase> elements(
+        FixedTypedArrayBase::cast(array->elements()));

[Camillo Bruni, 2017/03/13 09:02:30]

Another nit: you can avoid a handle allocation here since there is no gc going
to happen.

DisallowHeapAllocation no_gc;
BackingStore* elements = BackingStore::cast(receiver->elements());

[rongjie, 2017/03/13 10:46:40]

Done.

+    ctype* data = static_cast<ctype*>(elements->DataPtr());
+    std::fill(data + start, data + end, value);
+    return *array;
+  }
+
   static Maybe<bool> IncludesValueImpl(Isolate* isolate,
                                        Handle<JSObject> receiver,
                                        Handle<Object> value,