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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_OBJECTS_FIELD_INDEX_INL_H_
#define V8_OBJECTS_FIELD_INDEX_INL_H_
#include "src/ic/handler-configuration.h"
#include "src/objects/descriptor-array-inl.h"
#include "src/objects/field-index.h"
#include "src/objects/map-inl.h"
#include "src/objects/objects-inl.h"
namespace v8 {
namespace internal {
FieldIndex FieldIndex::ForInObjectOffset(int offset, Encoding encoding) {
DCHECK_IMPLIES(encoding == kWord32, IsAligned(offset, kInt32Size));
DCHECK_IMPLIES(encoding == kTagged, IsAligned(offset, kTaggedSize));
DCHECK_IMPLIES(encoding == kDouble, IsAligned(offset, kDoubleSize));
return FieldIndex(true, offset, encoding, 0, 0);
}
FieldIndex FieldIndex::ForSmiLoadHandler(Tagged<Map> map, int32_t handler) {
DCHECK_EQ(LoadHandler::KindBits::decode(handler), LoadHandler::Kind::kField);
bool is_inobject = LoadHandler::IsInobjectBits::decode(handler);
int inobject_properties = map->GetInObjectProperties();
int first_inobject_offset;
if (is_inobject) {
first_inobject_offset = map->GetInObjectPropertyOffset(0);
} else {
first_inobject_offset = FixedArray::kHeaderSize;
}
return FieldIndex(
is_inobject, LoadHandler::FieldIndexBits::decode(handler) * kTaggedSize,
LoadHandler::IsDoubleBits::decode(handler) ? kDouble : kTagged,
inobject_properties, first_inobject_offset);
}
FieldIndex FieldIndex::ForPropertyIndex(Tagged<Map> map, int property_index,
Representation representation) {
DCHECK(map->instance_type() >= FIRST_NONSTRING_TYPE);
int inobject_properties = map->GetInObjectProperties();
bool is_inobject = property_index < inobject_properties;
int first_inobject_offset;
int offset;
if (is_inobject) {
first_inobject_offset = map->GetInObjectPropertyOffset(0);
offset = map->GetInObjectPropertyOffset(property_index);
} else {
first_inobject_offset = FixedArray::kHeaderSize;
property_index -= inobject_properties;
offset = PropertyArray::OffsetOfElementAt(property_index);
}
Encoding encoding = FieldEncoding(representation);
return FieldIndex(is_inobject, offset, encoding, inobject_properties,
first_inobject_offset);
}
// Returns the index format accepted by the LoadFieldByIndex instruction.
// (In-object: zero-based from (object start + JSObject::kHeaderSize),
// out-of-object: zero-based from FixedArray::kHeaderSize.)
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 / kTaggedSize;
} else {
result -= FixedArray::kHeaderSize / kTaggedSize;
result = -result - 1;
}
result = static_cast<uint32_t>(result) << 1;
return is_double() ? (result | 1) : result;
}
FieldIndex FieldIndex::ForDescriptor(Tagged<Map> map,
InternalIndex descriptor_index) {
PtrComprCageBase cage_base = GetPtrComprCageBase(map);
return ForDescriptor(cage_base, map, descriptor_index);
}
FieldIndex FieldIndex::ForDescriptor(PtrComprCageBase cage_base,
Tagged<Map> map,
InternalIndex descriptor_index) {
PropertyDetails details = map->instance_descriptors(cage_base, kRelaxedLoad)
->GetDetails(descriptor_index);
return ForDetails(map, details);
}
FieldIndex FieldIndex::ForDetails(Tagged<Map> map, PropertyDetails details) {
int field_index = details.field_index();
return ForPropertyIndex(map, field_index, details.representation());
}
} // namespace internal
} // namespace v8
#endif // V8_OBJECTS_FIELD_INDEX_INL_H_
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