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// Copyright 2014 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.
#ifndef V8_FIELD_INDEX_INL_H_
#define V8_FIELD_INDEX_INL_H_
#include "src/field-index.h"
namespace v8 {
namespace internal {
inline FieldIndex FieldIndex::ForInObjectOffset(int offset, Map* map) {
DCHECK((offset % kPointerSize) == 0);
int index = offset / kPointerSize;
DCHECK(map == NULL ||
index < (map->GetInObjectPropertyOffset(0) / kPointerSize +
map->GetInObjectProperties()));
return FieldIndex(true, index, false, 0, 0, true);
}
inline FieldIndex FieldIndex::ForPropertyIndex(Map* map,
int property_index,
bool is_double) {
DCHECK(map->instance_type() >= FIRST_NONSTRING_TYPE);
int inobject_properties = map->GetInObjectProperties();
bool is_inobject = property_index < inobject_properties;
int first_inobject_offset;
if (is_inobject) {
first_inobject_offset = map->GetInObjectPropertyOffset(0);
} else {
first_inobject_offset = FixedArray::kHeaderSize;
property_index -= inobject_properties;
}
return FieldIndex(is_inobject,
property_index + first_inobject_offset / kPointerSize,
is_double, inobject_properties, first_inobject_offset);
}
// Takes an index as computed by GetLoadByFieldIndex and reconstructs a
// FieldIndex object from it.
inline FieldIndex FieldIndex::ForLoadByFieldIndex(Map* map, int orig_index) {
int field_index = orig_index;
int is_inobject = true;
bool is_double = field_index & 1;
int first_inobject_offset = 0;
field_index >>= 1;
if (field_index < 0) {
field_index = -(field_index + 1);
is_inobject = false;
first_inobject_offset = FixedArray::kHeaderSize;
field_index += FixedArray::kHeaderSize / kPointerSize;
} else {
first_inobject_offset = map->GetInObjectPropertyOffset(0);
field_index += JSObject::kHeaderSize / kPointerSize;
}
FieldIndex result(is_inobject, field_index, is_double,
map->GetInObjectProperties(), first_inobject_offset);
DCHECK(result.GetLoadByFieldIndex() == orig_index);
return result;
}
// Returns the index format accepted by the HLoadFieldByIndex instruction.
// (In-object: zero-based from (object start + JSObject::kHeaderSize),
// out-of-object: zero-based from FixedArray::kHeaderSize.)
inline int FieldIndex::GetLoadByFieldIndex() const {
// For efficiency, the LoadByFieldIndex instruction takes an index that is
// optimized for quick access. If the property is inline, the index is
// positive. If it's out-of-line, the encoded index is -raw_index - 1 to
// disambiguate the zero out-of-line index from the zero inobject case.
// The index itself is shifted up by one bit, the lower-most bit
// signifying if the field is a mutable double box (1) or not (0).
int result = index();
if (is_inobject()) {
result -= JSObject::kHeaderSize / kPointerSize;
} else {
result -= FixedArray::kHeaderSize / kPointerSize;
result = -result - 1;
}
result <<= 1;
return is_double() ? (result | 1) : result;
}
inline FieldIndex FieldIndex::ForDescriptor(Map* map, int descriptor_index) {
PropertyDetails details =
map->instance_descriptors()->GetDetails(descriptor_index);
int field_index = details.field_index();
return ForPropertyIndex(map, field_index,
details.representation().IsDouble());
}
inline FieldIndex FieldIndex::FromFieldAccessStubKey(int key) {
return FieldIndex(key);
}
} // namespace internal
} // namespace v8
#endif
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