Revert of Reland "LayoutDescriptor should inherit from JSTypedArray" (patchset...

Revert of Reland "LayoutDescriptor should inherit from JSTypedArray" (patchset #3 id:40001 of https://codereview.chromium.org/1094333002/)

Reason for revert:
Breaks gbemu

Original issue's description:
> Reland "LayoutDescriptor should inherit from JSTypedArray"
>
> Original issue's description:
> > LayoutDescriptor should inherit from JSTypedArray
> >
> > It can't just inherit from a FixedTypedArray-like type, as we soon
> > assume that a FixedTypedArray-like type is always held by an
> > ArrayBufferView-like type
> >
> > BUG=v8:3996
> > R=ishell@chromium.org,verwaest@chromium.org
> > LOG=n
>
> BUG=v8:3996
> R=ishell@chromium.org,verwaest@chromium.org
> LOG=n

TBR=ishell@chromium.org,verwaest@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:3996

Review URL: https://codereview.chromium.org/1080403004

Cr-Commit-Position: refs/heads/master@{#27975}

src/factory.cc

@@ -1825,38 +1825,9 @@ size_t GetExternalArrayElementSize(ExternalArrayType type) {
   case kExternal##Type##Array:                          \
     return size;
     TYPED_ARRAYS(TYPED_ARRAY_CASE)
-    default:
-      UNREACHABLE();
-      return 0;
-  }
-#undef TYPED_ARRAY_CASE
-}
-
-
-size_t GetFixedTypedArraysElementSize(ElementsKind kind) {
-  switch (kind) {
-#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
-  case TYPE##_ELEMENTS:                                 \
-    return size;
-    TYPED_ARRAYS(TYPED_ARRAY_CASE)
-    default:
-      UNREACHABLE();
-      return 0;
-  }
-#undef TYPED_ARRAY_CASE
-}
-
-
-ExternalArrayType GetArrayTypeFromElementsKind(ElementsKind kind) {
-  switch (kind) {
-#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
-  case TYPE##_ELEMENTS:                                 \
-    return kExternal##Type##Array;
-    TYPED_ARRAYS(TYPED_ARRAY_CASE)
-    default:
-      UNREACHABLE();
-      return kExternalInt8Array;
   }
+  UNREACHABLE();
+  return 0;
 #undef TYPED_ARRAY_CASE
 }
 
@@ -1878,23 +1849,6 @@ JSFunction* GetTypedArrayFun(ExternalArrayType type, Isolate* isolate) {
 }
 
 
-JSFunction* GetTypedArrayFun(ElementsKind elements_kind, Isolate* isolate) {
-  Context* native_context = isolate->context()->native_context();
-  switch (elements_kind) {
-#define TYPED_ARRAY_FUN(Type, type, TYPE, ctype, size) \
-  case TYPE##_ELEMENTS:                                \
-    return native_context->type##_array_fun();
-
-    TYPED_ARRAYS(TYPED_ARRAY_FUN)
-#undef TYPED_ARRAY_FUN
-
-    default:
-      UNREACHABLE();
-      return NULL;
-  }
-}
-
-
 void SetupArrayBufferView(i::Isolate* isolate,
                           i::Handle<i::JSArrayBufferView> obj,
                           i::Handle<i::JSArrayBuffer> buffer,
@@ -1936,16 +1890,6 @@ Handle<JSTypedArray> Factory::NewJSTypedArray(ExternalArrayType type) {
 }
 
 
-Handle<JSTypedArray> Factory::NewJSTypedArray(ElementsKind elements_kind) {
-  Handle<JSFunction> typed_array_fun_handle(
-      GetTypedArrayFun(elements_kind, isolate()));
-
-  CALL_HEAP_FUNCTION(
-      isolate(), isolate()->heap()->AllocateJSObject(*typed_array_fun_handle),
-      JSTypedArray);
-}
-
-
 Handle<JSTypedArray> Factory::NewJSTypedArray(ExternalArrayType type,
                                               Handle<JSArrayBuffer> buffer,
                                               size_t byte_offset,
@@ -1974,35 +1918,6 @@ Handle<JSTypedArray> Factory::NewJSTypedArray(ExternalArrayType type,
 }
 
 
-Handle<JSTypedArray> Factory::NewJSTypedArray(ElementsKind elements_kind,
-                                              size_t number_of_elements) {
-  Handle<JSTypedArray> obj = NewJSTypedArray(elements_kind);
-
-  size_t element_size = GetFixedTypedArraysElementSize(elements_kind);
-  ExternalArrayType array_type = GetArrayTypeFromElementsKind(elements_kind);
-
-  CHECK(number_of_elements <=
-        (std::numeric_limits<size_t>::max() / element_size));
-  CHECK(number_of_elements <= static_cast<size_t>(Smi::kMaxValue));
-  size_t byte_length = number_of_elements * element_size;
-
-  obj->set_byte_offset(Smi::FromInt(0));
-  i::Handle<i::Object> byte_length_object =
-      isolate()->factory()->NewNumberFromSize(byte_length);
-  obj->set_byte_length(*byte_length_object);
-  Handle<Object> length_object = NewNumberFromSize(number_of_elements);
-  obj->set_length(*length_object);
-
-  obj->set_buffer(Smi::FromInt(0));
-  obj->set_weak_next(isolate()->heap()->undefined_value());
-  Handle<FixedTypedArrayBase> elements =
-      isolate()->factory()->NewFixedTypedArray(
-          static_cast<int>(number_of_elements), array_type);
-  obj->set_elements(*elements);
-  return obj;
-}
-
-
 Handle<JSDataView> Factory::NewJSDataView(Handle<JSArrayBuffer> buffer,
                                           size_t byte_offset,
                                           size_t byte_length) {

src/factory.h

@@ -448,17 +448,11 @@ class Factory final {
 
   Handle<JSTypedArray> NewJSTypedArray(ExternalArrayType type);
 
-  Handle<JSTypedArray> NewJSTypedArray(ElementsKind elements_kind);
-
   // Creates a new JSTypedArray with the specified buffer.
   Handle<JSTypedArray> NewJSTypedArray(ExternalArrayType type,
                                        Handle<JSArrayBuffer> buffer,
                                        size_t byte_offset, size_t length);
 
-  // Creates a new on-heap JSTypedArray.
-  Handle<JSTypedArray> NewJSTypedArray(ElementsKind elements_kind,
-                                       size_t number_of_elements);
-
   Handle<JSDataView> NewJSDataView();
   Handle<JSDataView> NewJSDataView(Handle<JSArrayBuffer> buffer,
                                    size_t byte_offset, size_t byte_length);

src/layout-descriptor-inl.h

@@ -22,7 +22,7 @@ Handle<LayoutDescriptor> LayoutDescriptor::New(Isolate* isolate, int length) {
   }
   length = GetSlowModeBackingStoreLength(length);
   return Handle<LayoutDescriptor>::cast(
-      isolate->factory()->NewJSTypedArray(UINT32_ELEMENTS, length));
+      isolate->factory()->NewFixedTypedArray(length, kExternalUint32Array));
 }
 
 
@@ -48,7 +48,7 @@ bool LayoutDescriptor::GetIndexes(int field_index, int* layout_word_index,
   }
 
   *layout_word_index = field_index / kNumberOfBits;
-  CHECK((!IsSmi() && (*layout_word_index < Smi::cast(length())->value())) ||
+  CHECK((!IsSmi() && (*layout_word_index < length())) ||
         (IsSmi() && (*layout_word_index < 1)));
 
   *layout_bit_index = field_index % kNumberOfBits;
@@ -123,20 +123,7 @@ bool LayoutDescriptor::IsSlowLayout() { return !IsSmi(); }
 
 
 int LayoutDescriptor::capacity() {
-  return IsSlowLayout() ? (Smi::cast(length())->value() * kNumberOfBits)
-                        : kSmiValueSize;
-}
-
-
-uint32_t LayoutDescriptor::get_scalar(int index) {
-  DCHECK(IsSlowLayout());
-  return GcSafeElements()->get_scalar(index);
-}
-
-
-void LayoutDescriptor::set(int index, uint32_t value) {
-  DCHECK(IsSlowLayout());
-  GcSafeElements()->set(index, value);
+  return IsSlowLayout() ? (length() * kNumberOfBits) : kSmiValueSize;
 }
 
 
@@ -227,16 +214,6 @@ LayoutDescriptor* LayoutDescriptor::Initialize(
 }
 
 
-FixedTypedArray<Uint32ArrayTraits>* LayoutDescriptor::GcSafeElements() {
-  MapWord map_word = HeapObject::cast(elements())->map_word();
-  if (map_word.IsForwardingAddress()) {
-    return FixedTypedArray<Uint32ArrayTraits>::cast(
-        map_word.ToForwardingAddress());
-  }
-  return FixedTypedArray<Uint32ArrayTraits>::cast(elements());
-}
-
-
 // InobjectPropertiesHelper is a helper class for querying whether inobject
 // property at offset is Double or not.
 LayoutDescriptorHelper::LayoutDescriptorHelper(Map* map)

src/layout-descriptor.cc

@@ -106,11 +106,8 @@ Handle<LayoutDescriptor> LayoutDescriptor::EnsureCapacity(
   DCHECK(new_layout_descriptor->IsSlowLayout());
 
   if (layout_descriptor->IsSlowLayout()) {
-    DisallowHeapAllocation no_gc;
-    Handle<FixedTypedArrayBase> elements(layout_descriptor->GcSafeElements());
-    Handle<FixedTypedArrayBase> new_elements(
-        new_layout_descriptor->GcSafeElements());
-    memcpy(new_elements->DataPtr(), elements->DataPtr(), elements->DataSize());
+    memcpy(new_layout_descriptor->DataPtr(), layout_descriptor->DataPtr(),
+           layout_descriptor->DataSize());
     return new_layout_descriptor;
   } else {
     // Fast layout.
@@ -153,7 +150,7 @@ bool LayoutDescriptor::IsTagged(int field_index, int max_sequence_length,
     // This is a contiguous sequence till the end of current word, proceed
     // counting in the subsequent words.
     if (IsSlowLayout()) {
-      int len = Smi::cast(length())->value();
+      int len = length();
       ++layout_word_index;
       for (; layout_word_index < len; layout_word_index++) {
         value = get_scalar(layout_word_index);
@@ -244,20 +241,13 @@ LayoutDescriptor* LayoutDescriptor::Trim(Heap* heap, Map* map,
 
   // Trim, clean and reinitialize this slow-mode layout descriptor.
   int array_length = GetSlowModeBackingStoreLength(layout_descriptor_length);
-  int current_length = Smi::cast(length())->value();
+  int current_length = length();
   if (current_length != array_length) {
     DCHECK_LT(array_length, current_length);
     int delta = current_length - array_length;
-    heap->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>(elements(), delta);
-    set_byte_length(Smi::FromInt(array_length * 4));
-    set_length(Smi::FromInt(array_length));
-  }
-  {
-    DisallowHeapAllocation no_gc;
-    Handle<FixedTypedArrayBase> fixed_array(
-        FixedTypedArrayBase::cast(elements()));
-    memset(fixed_array->DataPtr(), 0, fixed_array->DataSize());
+    heap->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>(this, delta);
   }
+  memset(DataPtr(), 0, DataSize());
   LayoutDescriptor* layout_descriptor =
       Initialize(this, map, descriptors, num_descriptors);
   DCHECK_EQ(this, layout_descriptor);

src/layout-descriptor.h

@@ -22,7 +22,7 @@ namespace internal {
 // of the descriptor then the field is also considered tagged.
 // Once a layout descriptor is created it is allowed only to append properties
 // to it.
-class LayoutDescriptor : public JSTypedArray {
+class LayoutDescriptor : public FixedTypedArray<Uint32ArrayTraits> {
  public:
   V8_INLINE bool IsTagged(int field_index);
 
@@ -89,17 +89,12 @@ class LayoutDescriptor : public JSTypedArray {
   // Capacity of layout descriptors in bits.
   V8_INLINE int capacity();
 
-  V8_INLINE uint32_t get_scalar(int index);
-  V8_INLINE void set(int index, uint32_t value);
-
   static Handle<LayoutDescriptor> NewForTesting(Isolate* isolate, int length);
   LayoutDescriptor* SetTaggedForTesting(int field_index, bool tagged);
 
  private:
   static const int kNumberOfBits = 32;
 
-  V8_INLINE FixedTypedArray<Uint32ArrayTraits>* GcSafeElements();
-
   V8_INLINE static Handle<LayoutDescriptor> New(Isolate* isolate, int length);
   V8_INLINE static LayoutDescriptor* FromSmi(Smi* smi);
 

src/objects-inl.h

@@ -716,7 +716,9 @@ bool Object::IsDescriptorArray() const {
 bool Object::IsArrayList() const { return IsFixedArray(); }
 
 
-bool Object::IsLayoutDescriptor() const { return IsSmi() || IsJSTypedArray(); }
+bool Object::IsLayoutDescriptor() const {
+  return IsSmi() || IsFixedTypedArrayBase();
+}
 
 
 bool Object::IsTransitionArray() const {

src/objects-printer.cc

@@ -1065,7 +1065,7 @@ void LayoutDescriptor::Print(std::ostream& os) {  // NOLINT
     PrintBitMask(os, static_cast<uint32_t>(Smi::cast(this)->value()));
   } else {
     os << "slow";
-    int len = Smi::cast(length())->value();
+    int len = length();
     for (int i = 0; i < len; i++) {
       if (i > 0) os << " |";
       PrintBitMask(os, get_scalar(i));

test/cctest/test-unboxed-doubles.cc

@@ -581,7 +581,7 @@ TEST(LayoutDescriptorCreateNewSlow) {
     LayoutDescriptor* layout_desc = *layout_descriptor;
     CHECK_EQ(layout_desc, LayoutDescriptor::cast(layout_desc));
     CHECK_EQ(layout_desc, LayoutDescriptor::cast_gc_safe(layout_desc));
-    CHECK(layout_descriptor->IsJSTypedArray());
+    CHECK(layout_descriptor->IsFixedTypedArrayBase());
     // Now make it look like a forwarding pointer to layout_descriptor_copy.
     MapWord map_word = layout_desc->map_word();
     CHECK(!map_word.IsForwardingAddress());
@@ -935,7 +935,7 @@ TEST(DescriptorArrayTrimming) {
   CHECK(map->layout_descriptor()->IsConsistentWithMap(*map, true));
   CHECK(map->layout_descriptor()->IsSlowLayout());
   CHECK(map->owns_descriptors());
-  CHECK_EQ(2, Smi::cast(map->layout_descriptor()->length())->value());
+  CHECK_EQ(2, map->layout_descriptor()->length());
 
   {
     // Add transitions to double fields.
@@ -954,7 +954,7 @@ TEST(DescriptorArrayTrimming) {
     CHECK_EQ(map->layout_descriptor(), tmp_map->layout_descriptor());
   }
   CHECK(map->layout_descriptor()->IsSlowLayout());
-  CHECK_EQ(4, Smi::cast(map->layout_descriptor()->length())->value());
+  CHECK_EQ(4, map->layout_descriptor()->length());
 
   // The unused tail of the layout descriptor is now "durty" because of sharing.
   CHECK(map->layout_descriptor()->IsConsistentWithMap(*map));
@@ -974,7 +974,7 @@ TEST(DescriptorArrayTrimming) {
   CHECK_EQ(map->NumberOfOwnDescriptors(),
            map->instance_descriptors()->number_of_descriptors());
   CHECK(map->layout_descriptor()->IsSlowLayout());
-  CHECK_EQ(2, Smi::cast(map->layout_descriptor()->length())->value());
+  CHECK_EQ(2, map->layout_descriptor()->length());
 
   {
     // Add transitions to tagged fields.