Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2015 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #ifndef V8_OBJECTS_BODY_DESCRIPTORS_H_ |
| 6 | #define V8_OBJECTS_BODY_DESCRIPTORS_H_ |
| 7 | |
| 8 | #include "src/objects.h" |
| 9 | |
| 10 | namespace v8 { |
| 11 | namespace internal { |
| 12 | |
| 13 | // This is the base class for object's body descriptors. |
| 14 | // |
| 15 | // Each BodyDescriptor subclass must provide the following methods: |
| 16 | // |
| 17 | // 1) Returns true if the object contains a tagged value at given offset. |
| 18 | // It is used for invalid slots filtering. If the offset points outside |
| 19 | // of the object or to the map word, the result is UNDEFINED (!!!). |
| 20 | // |
| 21 | // static bool IsValidSlot(HeapObject* obj, int offset); |
| 22 | // |
| 23 | // |
| 24 | // 2) Iterate object's body using stateful object visitor. |
| 25 | // |
| 26 | // template <typename ObjectVisitor> |
| 27 | // static inline void IterateBody(HeapObject* obj, int object_size, |
| 28 | // ObjectVisitor* v); |
| 29 | // |
| 30 | // |
| 31 | // 3) Iterate object's body using stateless object visitor. |
| 32 | // |
| 33 | // template <typename StaticVisitor> |
| 34 | // static inline void IterateBody(HeapObject* obj, int object_size); |
| 35 | // |
| 36 | class BodyDescriptorBase BASE_EMBEDDED { |
| 37 | public: |
| 38 | template <typename ObjectVisitor> |
| 39 | static inline void IteratePointers(HeapObject* obj, int start_offset, |
| 40 | int end_offset, ObjectVisitor* v); |
| 41 | |
| 42 | template <typename StaticVisitor> |
| 43 | static inline void IteratePointers(Heap* heap, HeapObject* obj, |
| 44 | int start_offset, int end_offset); |
| 45 | |
| 46 | template <typename ObjectVisitor> |
| 47 | static inline void IteratePointer(HeapObject* obj, int offset, |
| 48 | ObjectVisitor* v); |
| 49 | |
| 50 | template <typename StaticVisitor> |
| 51 | static inline void IteratePointer(Heap* heap, HeapObject* obj, int offset); |
| 52 | |
| 53 | protected: |
| 54 | // Returns true for all header and internal fields. |
| 55 | static inline bool IsValidSlotImpl(HeapObject* obj, int offset); |
| 56 | |
| 57 | // Treats all header and internal fields in the range as tagged. |
| 58 | template <typename ObjectVisitor> |
| 59 | static inline void IterateBodyImpl(HeapObject* obj, int start_offset, |
| 60 | int end_offset, ObjectVisitor* v); |
| 61 | |
| 62 | // Treats all header and internal fields in the range as tagged. |
| 63 | template <typename StaticVisitor> |
| 64 | static inline void IterateBodyImpl(Heap* heap, HeapObject* obj, |
| 65 | int start_offset, int end_offset); |
| 66 | }; |
| 67 | |
| 68 | |
| 69 | // This class describes a body of an object of a fixed size |
| 70 | // in which all pointer fields are located in the [start_offset, end_offset) |
| 71 | // interval. |
| 72 | template <int start_offset, int end_offset, int size> |
| 73 | class FixedBodyDescriptor final : public BodyDescriptorBase { |
| 74 | public: |
| 75 | static const int kStartOffset = start_offset; |
| 76 | static const int kEndOffset = end_offset; |
| 77 | static const int kSize = size; |
| 78 | |
| 79 | static bool IsValidSlot(HeapObject* obj, int offset) { |
| 80 | return offset >= kStartOffset && offset < kEndOffset; |
| 81 | } |
| 82 | |
| 83 | template <typename ObjectVisitor> |
| 84 | static inline void IterateBody(HeapObject* obj, ObjectVisitor* v) { |
| 85 | IterateBodyImpl(obj, start_offset, end_offset, v); |
| 86 | } |
| 87 | |
| 88 | template <typename ObjectVisitor> |
| 89 | static inline void IterateBody(HeapObject* obj, int object_size, |
| 90 | ObjectVisitor* v) { |
| 91 | IterateBody(obj, v); |
| 92 | } |
| 93 | |
| 94 | template <typename StaticVisitor> |
| 95 | static inline void IterateBody(HeapObject* obj) { |
| 96 | Heap* heap = obj->GetHeap(); |
| 97 | IterateBodyImpl<StaticVisitor>(heap, obj, start_offset, end_offset); |
| 98 | } |
| 99 | |
| 100 | template <typename StaticVisitor> |
| 101 | static inline void IterateBody(HeapObject* obj, int object_size) { |
| 102 | IterateBody(obj); |
| 103 | } |
| 104 | }; |
| 105 | |
| 106 | |
| 107 | // This class describes a body of an object of a variable size |
| 108 | // in which all pointer fields are located in the [start_offset, object_size) |
| 109 | // interval. |
| 110 | template <int start_offset> |
| 111 | class FlexibleBodyDescriptor final : public BodyDescriptorBase { |
| 112 | public: |
| 113 | static const int kStartOffset = start_offset; |
| 114 | |
| 115 | static bool IsValidSlot(HeapObject* obj, int offset) { |
| 116 | if (offset < kStartOffset) return false; |
| 117 | return IsValidSlotImpl(obj, offset); |
| 118 | } |
| 119 | |
| 120 | template <typename ObjectVisitor> |
| 121 | static inline void IterateBody(HeapObject* obj, int object_size, |
| 122 | ObjectVisitor* v) { |
| 123 | IterateBodyImpl(obj, start_offset, object_size, v); |
| 124 | } |
| 125 | |
| 126 | template <typename StaticVisitor> |
| 127 | static inline void IterateBody(HeapObject* obj, int object_size) { |
| 128 | Heap* heap = obj->GetHeap(); |
| 129 | IterateBodyImpl<StaticVisitor>(heap, obj, start_offset, object_size); |
| 130 | } |
| 131 | |
| 132 | static inline int SizeOf(Map* map, HeapObject* object); |
| 133 | }; |
| 134 | |
| 135 | |
| 136 | typedef FlexibleBodyDescriptor<HeapObject::kHeaderSize> StructBodyDescriptor; |
| 137 | |
| 138 | } // namespace internal |
| 139 | } // namespace v8 |
| 140 | |
| 141 | #endif // V8_OBJECTS_BODY_DESCRIPTORS_H_ |