| // Copyright 2019 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_TAGGED_FIELD_H_ |
| #define V8_OBJECTS_TAGGED_FIELD_H_ |
| |
| #include "src/common/globals.h" |
| |
| #include "src/objects/objects.h" |
| #include "src/objects/tagged-value.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // This helper static class represents a tagged field of type T at offset |
| // kFieldOffset inside some host HeapObject. |
| // For full-pointer mode this type adds no overhead but when pointer |
| // compression is enabled such class allows us to use proper decompression |
| // function depending on the field type. |
| template <typename T, int kFieldOffset = 0> |
| class TaggedField : public AllStatic { |
| public: |
| static_assert(std::is_base_of<Object, T>::value || |
| std::is_same<MapWord, T>::value || |
| std::is_same<MaybeObject, T>::value, |
| "T must be strong or weak tagged type or MapWord"); |
| |
| // True for Smi fields. |
| static constexpr bool kIsSmi = std::is_base_of<Smi, T>::value; |
| |
| // True for HeapObject and MapWord fields. The latter may look like a Smi |
| // if it contains forwarding pointer but still requires tagged pointer |
| // decompression. |
| static constexpr bool kIsHeapObject = |
| std::is_base_of<HeapObject, T>::value || std::is_same<MapWord, T>::value; |
| |
| static inline Address address(HeapObject host, int offset = 0); |
| |
| static inline T load(HeapObject host, int offset = 0); |
| static inline T load(IsolateRoot isolate, HeapObject host, int offset = 0); |
| |
| static inline void store(HeapObject host, T value); |
| static inline void store(HeapObject host, int offset, T value); |
| |
| static inline T Relaxed_Load(HeapObject host, int offset = 0); |
| static inline T Relaxed_Load(IsolateRoot isolate, HeapObject host, |
| int offset = 0); |
| |
| static inline void Relaxed_Store(HeapObject host, T value); |
| static inline void Relaxed_Store(HeapObject host, int offset, T value); |
| |
| static inline T Acquire_Load(HeapObject host, int offset = 0); |
| static inline T Acquire_Load(IsolateRoot isolate, HeapObject host, |
| int offset = 0); |
| |
| static inline void Release_Store(HeapObject host, T value); |
| static inline void Release_Store(HeapObject host, int offset, T value); |
| |
| static inline Tagged_t Release_CompareAndSwap(HeapObject host, T old, |
| T value); |
| |
| private: |
| static inline Tagged_t* location(HeapObject host, int offset = 0); |
| |
| template <typename TOnHeapAddress> |
| static inline Address tagged_to_full(TOnHeapAddress on_heap_addr, |
| Tagged_t tagged_value); |
| |
| static inline Tagged_t full_to_tagged(Address value); |
| }; |
| |
| } // namespace internal |
| } // namespace v8 |
| |
| #endif // V8_OBJECTS_TAGGED_FIELD_H_ |