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1 // Copyright 2012 the V8 project authors. All rights reserved. | 1 // Copyright 2012 the V8 project authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef V8_ZONE_H_ | 5 #ifndef V8_ZONE_H_ |
6 #define V8_ZONE_H_ | 6 #define V8_ZONE_H_ |
7 | 7 |
8 #include <limits> | 8 #include <limits> |
9 | 9 |
10 #include "src/allocation.h" | 10 #include "src/base/accounting-allocator.h" |
11 #include "src/base/logging.h" | 11 #include "src/base/logging.h" |
12 #include "src/globals.h" | 12 #include "src/globals.h" |
13 #include "src/hashmap.h" | 13 #include "src/hashmap.h" |
14 #include "src/list.h" | 14 #include "src/list.h" |
15 #include "src/splay-tree.h" | 15 #include "src/splay-tree.h" |
16 | 16 |
17 namespace v8 { | 17 namespace v8 { |
18 namespace internal { | 18 namespace internal { |
19 | 19 |
20 // Forward declarations. | 20 // Forward declarations. |
21 class Segment; | 21 class Segment; |
22 | 22 |
23 | 23 |
24 // The Zone supports very fast allocation of small chunks of | 24 // The Zone supports very fast allocation of small chunks of |
25 // memory. The chunks cannot be deallocated individually, but instead | 25 // memory. The chunks cannot be deallocated individually, but instead |
26 // the Zone supports deallocating all chunks in one fast | 26 // the Zone supports deallocating all chunks in one fast |
27 // operation. The Zone is used to hold temporary data structures like | 27 // operation. The Zone is used to hold temporary data structures like |
28 // the abstract syntax tree, which is deallocated after compilation. | 28 // the abstract syntax tree, which is deallocated after compilation. |
29 // | 29 // |
30 // Note: There is no need to initialize the Zone; the first time an | 30 // Note: There is no need to initialize the Zone; the first time an |
31 // allocation is attempted, a segment of memory will be requested | 31 // allocation is attempted, a segment of memory will be requested |
32 // through a call to malloc(). | 32 // through a call to malloc(). |
33 // | 33 // |
34 // Note: The implementation is inherently not thread safe. Do not use | 34 // Note: The implementation is inherently not thread safe. Do not use |
35 // from multi-threaded code. | 35 // from multi-threaded code. |
36 class Zone final { | 36 class Zone final { |
37 public: | 37 public: |
38 Zone(); | 38 explicit Zone(base::AccountingAllocator* allocator); |
39 ~Zone(); | 39 ~Zone(); |
40 | 40 |
41 // Allocate 'size' bytes of memory in the Zone; expands the Zone by | 41 // Allocate 'size' bytes of memory in the Zone; expands the Zone by |
42 // allocating new segments of memory on demand using malloc(). | 42 // allocating new segments of memory on demand using malloc(). |
43 void* New(size_t size); | 43 void* New(size_t size); |
44 | 44 |
45 template <typename T> | 45 template <typename T> |
46 T* NewArray(size_t length) { | 46 T* NewArray(size_t length) { |
47 DCHECK_LT(length, std::numeric_limits<size_t>::max() / sizeof(T)); | 47 DCHECK_LT(length, std::numeric_limits<size_t>::max() / sizeof(T)); |
48 return static_cast<T*>(New(length * sizeof(T))); | 48 return static_cast<T*>(New(length * sizeof(T))); |
49 } | 49 } |
50 | 50 |
51 // Deletes all objects and free all memory allocated in the Zone. Keeps one | 51 // Deletes all objects and free all memory allocated in the Zone. Keeps one |
52 // small (size <= kMaximumKeptSegmentSize) segment around if it finds one. | 52 // small (size <= kMaximumKeptSegmentSize) segment around if it finds one. |
53 void DeleteAll(); | 53 void DeleteAll(); |
54 | 54 |
55 // Deletes the last small segment kept around by DeleteAll(). You | 55 // Deletes the last small segment kept around by DeleteAll(). You |
56 // may no longer allocate in the Zone after a call to this method. | 56 // may no longer allocate in the Zone after a call to this method. |
57 void DeleteKeptSegment(); | 57 void DeleteKeptSegment(); |
58 | 58 |
59 // Returns true if more memory has been allocated in zones than | 59 // Returns true if more memory has been allocated in zones than |
60 // the limit allows. | 60 // the limit allows. |
61 bool excess_allocation() const { | 61 bool excess_allocation() const { |
62 return segment_bytes_allocated_ > kExcessLimit; | 62 return segment_bytes_allocated_ > kExcessLimit; |
63 } | 63 } |
64 | 64 |
65 size_t allocation_size() const { return allocation_size_; } | 65 size_t allocation_size() const { return allocation_size_; } |
66 | 66 |
| 67 base::AccountingAllocator* allocator() const { return allocator_; } |
| 68 |
67 private: | 69 private: |
68 // All pointers returned from New() have this alignment. In addition, if the | 70 // All pointers returned from New() have this alignment. In addition, if the |
69 // object being allocated has a size that is divisible by 8 then its alignment | 71 // object being allocated has a size that is divisible by 8 then its alignment |
70 // will be 8. ASan requires 8-byte alignment. | 72 // will be 8. ASan requires 8-byte alignment. |
71 #ifdef V8_USE_ADDRESS_SANITIZER | 73 #ifdef V8_USE_ADDRESS_SANITIZER |
72 static const size_t kAlignment = 8; | 74 static const size_t kAlignment = 8; |
73 STATIC_ASSERT(kPointerSize <= 8); | 75 STATIC_ASSERT(kPointerSize <= 8); |
74 #else | 76 #else |
75 static const size_t kAlignment = kPointerSize; | 77 static const size_t kAlignment = kPointerSize; |
76 #endif | 78 #endif |
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107 | 109 |
108 // Deletes the given segment. Does not touch the segment chain. | 110 // Deletes the given segment. Does not touch the segment chain. |
109 inline void DeleteSegment(Segment* segment, size_t size); | 111 inline void DeleteSegment(Segment* segment, size_t size); |
110 | 112 |
111 // The free region in the current (front) segment is represented as | 113 // The free region in the current (front) segment is represented as |
112 // the half-open interval [position, limit). The 'position' variable | 114 // the half-open interval [position, limit). The 'position' variable |
113 // is guaranteed to be aligned as dictated by kAlignment. | 115 // is guaranteed to be aligned as dictated by kAlignment. |
114 Address position_; | 116 Address position_; |
115 Address limit_; | 117 Address limit_; |
116 | 118 |
| 119 base::AccountingAllocator* allocator_; |
| 120 |
117 Segment* segment_head_; | 121 Segment* segment_head_; |
118 }; | 122 }; |
119 | 123 |
120 | 124 |
121 // ZoneObject is an abstraction that helps define classes of objects | 125 // ZoneObject is an abstraction that helps define classes of objects |
122 // allocated in the Zone. Use it as a base class; see ast.h. | 126 // allocated in the Zone. Use it as a base class; see ast.h. |
123 class ZoneObject { | 127 class ZoneObject { |
124 public: | 128 public: |
125 // Allocate a new ZoneObject of 'size' bytes in the Zone. | 129 // Allocate a new ZoneObject of 'size' bytes in the Zone. |
126 void* operator new(size_t size, Zone* zone) { return zone->New(size); } | 130 void* operator new(size_t size, Zone* zone) { return zone->New(size); } |
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240 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } | 244 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } |
241 }; | 245 }; |
242 | 246 |
243 | 247 |
244 typedef TemplateHashMapImpl<ZoneAllocationPolicy> ZoneHashMap; | 248 typedef TemplateHashMapImpl<ZoneAllocationPolicy> ZoneHashMap; |
245 | 249 |
246 } // namespace internal | 250 } // namespace internal |
247 } // namespace v8 | 251 } // namespace v8 |
248 | 252 |
249 #endif // V8_ZONE_H_ | 253 #endif // V8_ZONE_H_ |
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