c5a492961f
R=verwaest@chromium.org Review URL: https://codereview.chromium.org/711313002 Cr-Commit-Position: refs/heads/master@{#25258} git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25258 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
117 lines
3.8 KiB
C++
117 lines
3.8 KiB
C++
// Copyright 2014 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef V8_FIELD_INDEX_H_
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#define V8_FIELD_INDEX_H_
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#include "src/property-details.h"
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#include "src/utils.h"
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namespace v8 {
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namespace internal {
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class Map;
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// Wrapper class to hold a field index, usually but not necessarily generated
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// from a property index. When available, the wrapper class captures additional
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// information to allow the field index to be translated back into the property
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// index it was originally generated from.
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class FieldIndex FINAL {
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public:
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static FieldIndex ForPropertyIndex(Map* map,
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int index,
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bool is_double = false);
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static FieldIndex ForInObjectOffset(int offset, Map* map = NULL);
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static FieldIndex ForDescriptor(Map* map, int descriptor_index);
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static FieldIndex ForLoadByFieldIndex(Map* map, int index);
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static FieldIndex ForKeyedLookupCacheIndex(Map* map, int index);
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static FieldIndex FromFieldAccessStubKey(int key);
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int GetLoadByFieldIndex() const;
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bool is_inobject() const {
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return IsInObjectBits::decode(bit_field_);
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}
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bool is_hidden_field() const { return IsHiddenField::decode(bit_field_); }
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bool is_double() const {
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return IsDoubleBits::decode(bit_field_);
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}
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int offset() const {
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return index() * kPointerSize;
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}
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// Zero-indexed from beginning of the object.
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int index() const {
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return IndexBits::decode(bit_field_);
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}
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int outobject_array_index() const {
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DCHECK(!is_inobject());
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return index() - first_inobject_property_offset() / kPointerSize;
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}
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// Zero-based from the first inobject property. Overflows to out-of-object
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// properties.
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int property_index() const {
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DCHECK(!is_hidden_field());
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int result = index() - first_inobject_property_offset() / kPointerSize;
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if (!is_inobject()) {
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result += InObjectPropertyBits::decode(bit_field_);
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}
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return result;
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}
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int GetKeyedLookupCacheIndex() const;
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int GetFieldAccessStubKey() const {
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return bit_field_ &
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(IsInObjectBits::kMask | IsDoubleBits::kMask | IndexBits::kMask);
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}
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private:
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FieldIndex(bool is_inobject, int local_index, bool is_double,
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int inobject_properties, int first_inobject_property_offset,
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bool is_hidden = false) {
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DCHECK((first_inobject_property_offset & (kPointerSize - 1)) == 0);
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bit_field_ = IsInObjectBits::encode(is_inobject) |
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IsDoubleBits::encode(is_double) |
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FirstInobjectPropertyOffsetBits::encode(first_inobject_property_offset) |
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IsHiddenField::encode(is_hidden) |
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IndexBits::encode(local_index) |
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InObjectPropertyBits::encode(inobject_properties);
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}
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explicit FieldIndex(int bit_field) : bit_field_(bit_field) {}
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int first_inobject_property_offset() const {
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DCHECK(!is_hidden_field());
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return FirstInobjectPropertyOffsetBits::decode(bit_field_);
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}
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static const int kIndexBitsSize = kDescriptorIndexBitCount + 1;
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// Index from beginning of object.
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class IndexBits: public BitField<int, 0, kIndexBitsSize> {};
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class IsInObjectBits: public BitField<bool, IndexBits::kNext, 1> {};
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class IsDoubleBits: public BitField<bool, IsInObjectBits::kNext, 1> {};
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// Number of inobject properties.
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class InObjectPropertyBits
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: public BitField<int, IsDoubleBits::kNext, kDescriptorIndexBitCount> {};
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// Offset of first inobject property from beginning of object.
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class FirstInobjectPropertyOffsetBits
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: public BitField<int, InObjectPropertyBits::kNext, 7> {};
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class IsHiddenField
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: public BitField<bool, FirstInobjectPropertyOffsetBits::kNext, 1> {};
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STATIC_ASSERT(IsHiddenField::kNext <= 32);
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int bit_field_;
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};
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} } // namespace v8::internal
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#endif
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