[turbofan] Fix typed lowering of typed array loads/stores.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index 25d8cd80e50c75f4b2eb3a4d72bf6b831058c575..60ea691d916ff071dfec04459bdccd7c34c7b0fd 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -1731,6 +1731,19 @@ ElementsKind GetExternalArrayElementsKind(ExternalArrayType type) {
 }
 
 
+size_t GetExternalArrayElementSize(ExternalArrayType type) {
+  switch (type) {
+#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
+  case kExternal##Type##Array:                          \
+    return size;
+    TYPED_ARRAYS(TYPED_ARRAY_CASE)
+  }
+  UNREACHABLE();
+  return 0;
+#undef TYPED_ARRAY_CASE
+}
+
+
 JSFunction* GetTypedArrayFun(ExternalArrayType type, Isolate* isolate) {
   Context* native_context = isolate->context()->native_context();
   switch (type) {
@@ -1769,7 +1782,9 @@ Handle<JSTypedArray> Factory::NewJSTypedArray(ExternalArrayType type,
   array->set_weak_next(buffer->weak_first_view());
   buffer->set_weak_first_view(*array);
   array->set_byte_offset(Smi::FromInt(0));
-  array->set_byte_length(buffer->byte_length());
+  Handle<Object> byte_length_handle =

[Dmitry Lomov (no reviews), 2014/10/10 08:43:02]

DBC: why we have this Factory::NewJSTypedArray?

Where is it used?

Can we add a proper byte_offset argument to it?

Can we add proper validation of all arguments and sizes? (byte length fits into
ArrayBuffer etc?) Historically, this is a place where security bugs brew. 

+      NewNumberFromSize(length * GetExternalArrayElementSize(type));
+  array->set_byte_length(*byte_length_handle);
   Handle<Object> length_handle = NewNumberFromSize(length);
   array->set_length(*length_handle);
   Handle<ExternalArray> elements =