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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/elements-kind.h"
#include "src/api.h"
#include "src/base/lazy-instance.h"
#include "src/elements.h"
#include "src/objects-inl.h"
#include "src/objects.h"
namespace v8 {
namespace internal {
int ElementsKindToShiftSize(ElementsKind elements_kind) {
switch (elements_kind) {
case UINT8_ELEMENTS:
case INT8_ELEMENTS:
case UINT8_CLAMPED_ELEMENTS:
return 0;
case UINT16_ELEMENTS:
case INT16_ELEMENTS:
return 1;
case UINT32_ELEMENTS:
case INT32_ELEMENTS:
case FLOAT32_ELEMENTS:
return 2;
case FAST_DOUBLE_ELEMENTS:
case FAST_HOLEY_DOUBLE_ELEMENTS:
case FLOAT64_ELEMENTS:
return 3;
case FAST_SMI_ELEMENTS:
case FAST_ELEMENTS:
case FAST_HOLEY_SMI_ELEMENTS:
case FAST_HOLEY_ELEMENTS:
case DICTIONARY_ELEMENTS:
case FAST_SLOPPY_ARGUMENTS_ELEMENTS:
case SLOW_SLOPPY_ARGUMENTS_ELEMENTS:
case FAST_STRING_WRAPPER_ELEMENTS:
case SLOW_STRING_WRAPPER_ELEMENTS:
return kPointerSizeLog2;
case NO_ELEMENTS:
UNREACHABLE();
return 0;
}
UNREACHABLE();
return 0;
}
int GetDefaultHeaderSizeForElementsKind(ElementsKind elements_kind) {
STATIC_ASSERT(FixedArray::kHeaderSize == FixedDoubleArray::kHeaderSize);
if (IsFixedTypedArrayElementsKind(elements_kind)) {
return 0;
} else {
return FixedArray::kHeaderSize - kHeapObjectTag;
}
}
const char* ElementsKindToString(ElementsKind kind) {
ElementsAccessor* accessor = ElementsAccessor::ForKind(kind);
return accessor->name();
}
struct InitializeFastElementsKindSequence {
static void Construct(
ElementsKind** fast_elements_kind_sequence_ptr) {
ElementsKind* fast_elements_kind_sequence =
new ElementsKind[kFastElementsKindCount];
*fast_elements_kind_sequence_ptr = fast_elements_kind_sequence;
STATIC_ASSERT(FAST_SMI_ELEMENTS == FIRST_FAST_ELEMENTS_KIND);
fast_elements_kind_sequence[0] = FAST_SMI_ELEMENTS;
fast_elements_kind_sequence[1] = FAST_HOLEY_SMI_ELEMENTS;
fast_elements_kind_sequence[2] = FAST_DOUBLE_ELEMENTS;
fast_elements_kind_sequence[3] = FAST_HOLEY_DOUBLE_ELEMENTS;
fast_elements_kind_sequence[4] = FAST_ELEMENTS;
fast_elements_kind_sequence[5] = FAST_HOLEY_ELEMENTS;
// Verify that kFastElementsKindPackedToHoley is correct.
STATIC_ASSERT(FAST_SMI_ELEMENTS + kFastElementsKindPackedToHoley ==
FAST_HOLEY_SMI_ELEMENTS);
STATIC_ASSERT(FAST_DOUBLE_ELEMENTS + kFastElementsKindPackedToHoley ==
FAST_HOLEY_DOUBLE_ELEMENTS);
STATIC_ASSERT(FAST_ELEMENTS + kFastElementsKindPackedToHoley ==
FAST_HOLEY_ELEMENTS);
}
};
static base::LazyInstance<ElementsKind*,
InitializeFastElementsKindSequence>::type
fast_elements_kind_sequence = LAZY_INSTANCE_INITIALIZER;
ElementsKind GetFastElementsKindFromSequenceIndex(int sequence_number) {
DCHECK(sequence_number >= 0 &&
sequence_number < kFastElementsKindCount);
return fast_elements_kind_sequence.Get()[sequence_number];
}
int GetSequenceIndexFromFastElementsKind(ElementsKind elements_kind) {
for (int i = 0; i < kFastElementsKindCount; ++i) {
if (fast_elements_kind_sequence.Get()[i] == elements_kind) {
return i;
}
}
UNREACHABLE();
return 0;
}
ElementsKind GetNextTransitionElementsKind(ElementsKind kind) {
int index = GetSequenceIndexFromFastElementsKind(kind);
return GetFastElementsKindFromSequenceIndex(index + 1);
}
static inline bool IsFastTransitionTarget(ElementsKind elements_kind) {
return IsFastElementsKind(elements_kind) ||
elements_kind == DICTIONARY_ELEMENTS;
}
bool IsMoreGeneralElementsKindTransition(ElementsKind from_kind,
ElementsKind to_kind) {
if (IsFixedTypedArrayElementsKind(from_kind) ||
IsFixedTypedArrayElementsKind(to_kind)) {
return false;
}
if (IsFastElementsKind(from_kind) && IsFastTransitionTarget(to_kind)) {
switch (from_kind) {
case FAST_SMI_ELEMENTS:
return to_kind != FAST_SMI_ELEMENTS;
case FAST_HOLEY_SMI_ELEMENTS:
return to_kind != FAST_SMI_ELEMENTS &&
to_kind != FAST_HOLEY_SMI_ELEMENTS;
case FAST_DOUBLE_ELEMENTS:
return to_kind != FAST_SMI_ELEMENTS &&
to_kind != FAST_HOLEY_SMI_ELEMENTS &&
to_kind != FAST_DOUBLE_ELEMENTS;
case FAST_HOLEY_DOUBLE_ELEMENTS:
return to_kind == FAST_ELEMENTS ||
to_kind == FAST_HOLEY_ELEMENTS;
case FAST_ELEMENTS:
return to_kind == FAST_HOLEY_ELEMENTS;
case FAST_HOLEY_ELEMENTS:
return false;
default:
return false;
}
}
return false;
}
} // namespace internal
} // namespace v8
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