| // Copyright 2018 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_EMBEDDER_DATA_SLOT_H_ |
| #define V8_OBJECTS_EMBEDDER_DATA_SLOT_H_ |
| |
| #include <utility> |
| |
| #include "src/assert-scope.h" |
| #include "src/globals.h" |
| #include "src/objects/slots.h" |
| |
| // Has to be the last include (doesn't have include guards): |
| #include "src/objects/object-macros.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| class EmbedderDataArray; |
| class JSObject; |
| class Object; |
| |
| // An EmbedderDataSlot instance describes a kEmbedderDataSlotSize field ("slot") |
| // holding an embedder data which may contain raw aligned pointer or a tagged |
| // pointer (smi or heap object). |
| // Its address() is the address of the slot. |
| // The slot's contents can be read and written using respective load_XX() and |
| // store_XX() methods. |
| // Storing heap object through this slot may require triggering write barriers |
| // so this operation must be done via static store_tagged() methods. |
| class EmbedderDataSlot |
| : public SlotBase<EmbedderDataSlot, Address, kEmbedderDataSlotSize> { |
| public: |
| EmbedderDataSlot() : SlotBase(kNullAddress) {} |
| V8_INLINE EmbedderDataSlot(EmbedderDataArray array, int entry_index); |
| V8_INLINE EmbedderDataSlot(JSObject object, int embedder_field_index); |
| |
| #ifdef V8_COMPRESS_POINTERS |
| static constexpr int kRawPayloadOffset = kTaggedSize; |
| #endif |
| static constexpr int kTaggedPayloadOffset = 0; |
| static constexpr int kRequiredPtrAlignment = kSmiTagSize; |
| |
| // Opaque type used for storing raw embedder data. |
| struct RawData { |
| const Address data_[kEmbedderDataSlotSizeInTaggedSlots]; |
| }; |
| |
| V8_INLINE Object* load_tagged() const; |
| V8_INLINE void store_smi(Smi value); |
| |
| // Setting an arbitrary tagged value requires triggering a write barrier |
| // which requires separate object and offset values, therefore these static |
| // functions a |
| static V8_INLINE void store_tagged(EmbedderDataArray array, int entry_index, |
| Object* value); |
| static V8_INLINE void store_tagged(JSObject object, int embedder_field_index, |
| Object* value); |
| |
| // Tries reinterpret the value as an aligned pointer and on success sets |
| // *out_result to the pointer-like value and returns true. Note, that some |
| // Smis could still look like an aligned pointers. |
| // Returns false otherwise. |
| V8_INLINE bool ToAlignedPointer(void** out_result) const; |
| |
| // Returns true if the pointer was successfully stored or false it the pointer |
| // was improperly aligned. |
| V8_INLINE V8_WARN_UNUSED_RESULT bool store_aligned_pointer(void* ptr); |
| |
| V8_INLINE RawData load_raw(const DisallowHeapAllocation& no_gc) const; |
| V8_INLINE void store_raw(const RawData& data, |
| const DisallowHeapAllocation& no_gc); |
| }; |
| |
| } // namespace internal |
| } // namespace v8 |
| |
| #include "src/objects/object-macros-undef.h" |
| |
| #endif // V8_OBJECTS_EMBEDDER_DATA_SLOT_H_ |