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

src/builtins/builtins-typedarray.cc

Index: src/builtins/builtins-typedarray.cc
diff --git a/src/builtins/builtins-typedarray.cc b/src/builtins/builtins-typedarray.cc
index 8a8bde4be027a1329ccaaea4dfe92d75c32957a3..96b129eec1268815991ddb6eb018b045acf704cf 100644
--- a/src/builtins/builtins-typedarray.cc
+++ b/src/builtins/builtins-typedarray.cc
@@ -399,8 +399,6 @@ BUILTIN(TypedArrayPrototypeCopyWithin) {
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, array, JSTypedArray::Validate(isolate, args.receiver(), method));
 
-  if (V8_UNLIKELY(array->WasNeutered())) return *array;
-
   int64_t len = array->length_value();
   int64_t to = 0;
   int64_t from = 0;
@@ -456,5 +454,77 @@ BUILTIN(TypedArrayPrototypeCopyWithin) {
   return *array;
 }
 
+BUILTIN(TypedArrayPrototypeFill) {
+  HandleScope scope(isolate);
+
+  Handle<JSTypedArray> array;
+  const char* method = "%TypedArray%.prototype.fill";
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, array, JSTypedArray::Validate(isolate, args.receiver(), method));
+
+  int64_t len = array->length_value();
+  int64_t start = 0;
+  int64_t end = len;
+  double value = 0.0;
+
+  if (V8_LIKELY(args.length() > 1)) {
+    Handle<Object> num;
+    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+        isolate, num, Object::ToNumber(args.at<Object>(1)));
+
+    if (num->IsSmi()) {
+      value = Smi::cast(*num)->value();
+    } else {
+      DCHECK(num->IsHeapNumber());
+      value = HeapNumber::cast(*num)->value();
+    }
+    if (array->type() == kExternalUint8ClampedArray) {
+      value = std::min<double>(std::max<double>(0, value), 255);
+    }
+
+    Handle<Object> optional = args.atOrUndefined(isolate, 2);
+    if (!optional->IsUndefined(isolate)) {
+      ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+          isolate, num, Object::ToInteger(isolate, optional));
+      start = CapRelativeIndex(num, 0, len);
+
+      optional = args.atOrUndefined(isolate, 3);
+      if (!optional->IsUndefined(isolate)) {
+        ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+            isolate, num, Object::ToInteger(isolate, optional));
+        end = CapRelativeIndex(num, 0, len);
+      }
+    }
+  }
+
+  int64_t count = end - start;
+  if (count <= 0) return *array;
+
+  if (V8_UNLIKELY(array->WasNeutered())) return *array;
+
+  // Ensure processed indexes are within array bounds
+  DCHECK_GE(start, 0);
+  DCHECK_LT(start, len);
+  DCHECK_GE(end, 0);
+  DCHECK_LE(end, len);
+  DCHECK_LE(count, len);
+
+  switch (array->type()) {
+#define TYPED_ARRAY_FILL(Type, type, TYPE, ctype, size)                \
+  case kExternal##Type##Array: {                                       \
+    ctype* backing_store =                                             \
+        static_cast<ctype*>(array->GetBuffer()->backing_store());      \

[Choongwoo Han, 2017/03/08 08:18:30]

You should consider byte_offset for backing_store.

+    ctype cast_value = static_cast<ctype>(value);                         \
+    std::fill(backing_store + start, backing_store + end, cast_value); \
+    break;                                                             \
+  }
+
+    TYPED_ARRAYS(TYPED_ARRAY_FILL)
+#undef TYPED_ARRAY_FILL
+  }
+
+  return *array;
+}
+
 }  // namespace internal
 }  // namespace v8