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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/base/accounting-allocator.h" | |
| 11 #include "src/base/hashmap.h" | 10 #include "src/base/hashmap.h" |
| 12 #include "src/base/logging.h" | 11 #include "src/base/logging.h" |
| 13 #include "src/globals.h" | 12 #include "src/globals.h" |
| 14 #include "src/list.h" | 13 #include "src/list.h" |
| 15 #include "src/splay-tree.h" | 14 #include "src/splay-tree.h" |
| 15 #include "src/zone/accounting-allocator.h" |
| 16 | 16 |
| 17 namespace v8 { | 17 namespace v8 { |
| 18 namespace internal { | 18 namespace internal { |
| 19 | 19 |
| 20 // Forward declarations. | |
| 21 class Segment; | |
| 22 | |
| 23 | |
| 24 // The Zone supports very fast allocation of small chunks of | 20 // The Zone supports very fast allocation of small chunks of |
| 25 // memory. The chunks cannot be deallocated individually, but instead | 21 // memory. The chunks cannot be deallocated individually, but instead |
| 26 // the Zone supports deallocating all chunks in one fast | 22 // the Zone supports deallocating all chunks in one fast |
| 27 // operation. The Zone is used to hold temporary data structures like | 23 // operation. The Zone is used to hold temporary data structures like |
| 28 // the abstract syntax tree, which is deallocated after compilation. | 24 // the abstract syntax tree, which is deallocated after compilation. |
| 29 // | 25 // |
| 30 // Note: There is no need to initialize the Zone; the first time an | 26 // Note: There is no need to initialize the Zone; the first time an |
| 31 // allocation is attempted, a segment of memory will be requested | 27 // allocation is attempted, a segment of memory will be requested |
| 32 // through a call to malloc(). | 28 // through a call to malloc(). |
| 33 // | 29 // |
| 34 // Note: The implementation is inherently not thread safe. Do not use | 30 // Note: The implementation is inherently not thread safe. Do not use |
| 35 // from multi-threaded code. | 31 // from multi-threaded code. |
| 36 class Zone final { | 32 class Zone final { |
| 37 public: | 33 public: |
| 38 explicit Zone(base::AccountingAllocator* allocator); | 34 explicit Zone(AccountingAllocator* allocator); |
| 39 ~Zone(); | 35 ~Zone(); |
| 40 | 36 |
| 41 // Allocate 'size' bytes of memory in the Zone; expands the Zone by | 37 // Allocate 'size' bytes of memory in the Zone; expands the Zone by |
| 42 // allocating new segments of memory on demand using malloc(). | 38 // allocating new segments of memory on demand using malloc(). |
| 43 void* New(size_t size); | 39 void* New(size_t size); |
| 44 | 40 |
| 45 template <typename T> | 41 template <typename T> |
| 46 T* NewArray(size_t length) { | 42 T* NewArray(size_t length) { |
| 47 DCHECK_LT(length, std::numeric_limits<size_t>::max() / sizeof(T)); | 43 DCHECK_LT(length, std::numeric_limits<size_t>::max() / sizeof(T)); |
| 48 return static_cast<T*>(New(length * sizeof(T))); | 44 return static_cast<T*>(New(length * sizeof(T))); |
| 49 } | 45 } |
| 50 | 46 |
| 51 // Deletes all objects and free all memory allocated in the Zone. Keeps one | 47 // Deletes all objects and free all memory allocated in the Zone. Keeps one |
| 52 // small (size <= kMaximumKeptSegmentSize) segment around if it finds one. | 48 // small (size <= kMaximumKeptSegmentSize) segment around if it finds one. |
| 53 void DeleteAll(); | 49 void DeleteAll(); |
| 54 | 50 |
| 55 // Deletes the last small segment kept around by DeleteAll(). You | 51 // Deletes the last small segment kept around by DeleteAll(). You |
| 56 // may no longer allocate in the Zone after a call to this method. | 52 // may no longer allocate in the Zone after a call to this method. |
| 57 void DeleteKeptSegment(); | 53 void DeleteKeptSegment(); |
| 58 | 54 |
| 59 // Returns true if more memory has been allocated in zones than | 55 // Returns true if more memory has been allocated in zones than |
| 60 // the limit allows. | 56 // the limit allows. |
| 61 bool excess_allocation() const { | 57 bool excess_allocation() const { |
| 62 return segment_bytes_allocated_ > kExcessLimit; | 58 return segment_bytes_allocated_ > kExcessLimit; |
| 63 } | 59 } |
| 64 | 60 |
| 65 size_t allocation_size() const { return allocation_size_; } | 61 size_t allocation_size() const { return allocation_size_; } |
| 66 | 62 |
| 67 base::AccountingAllocator* allocator() const { return allocator_; } | 63 AccountingAllocator* allocator() const { return allocator_; } |
| 68 | 64 |
| 69 private: | 65 private: |
| 70 // All pointers returned from New() have this alignment. In addition, if the | 66 friend class SegmentPool; |
| 71 // object being allocated has a size that is divisible by 8 then its alignment | 67 // All pointers returned from New() have this alignment. In addition, if the |
| 72 // will be 8. ASan requires 8-byte alignment. | 68 // object being allocated has a size that is divisible by 8 then its alignment |
| 69 // will be 8. ASan requires 8-byte alignment. |
| 73 #ifdef V8_USE_ADDRESS_SANITIZER | 70 #ifdef V8_USE_ADDRESS_SANITIZER |
| 74 static const size_t kAlignment = 8; | 71 static const size_t kAlignment = 8; |
| 75 STATIC_ASSERT(kPointerSize <= 8); | 72 STATIC_ASSERT(kPointerSize <= 8); |
| 76 #else | 73 #else |
| 77 static const size_t kAlignment = kPointerSize; | 74 static const size_t kAlignment = kPointerSize; |
| 78 #endif | 75 #endif |
| 79 | 76 |
| 80 // Never allocate segments smaller than this size in bytes. | 77 // Never allocate segments smaller than this size in bytes. |
| 81 static const size_t kMinimumSegmentSize = 8 * KB; | 78 static const size_t kMinimumSegmentSize = 8 * KB; |
| 82 | 79 |
| (...skipping 17 matching lines...) Expand all Loading... |
| 100 // Expand the Zone to hold at least 'size' more bytes and allocate | 97 // Expand the Zone to hold at least 'size' more bytes and allocate |
| 101 // the bytes. Returns the address of the newly allocated chunk of | 98 // the bytes. Returns the address of the newly allocated chunk of |
| 102 // memory in the Zone. Should only be called if there isn't enough | 99 // memory in the Zone. Should only be called if there isn't enough |
| 103 // room in the Zone already. | 100 // room in the Zone already. |
| 104 Address NewExpand(size_t size); | 101 Address NewExpand(size_t size); |
| 105 | 102 |
| 106 // Creates a new segment, sets it size, and pushes it to the front | 103 // Creates a new segment, sets it size, and pushes it to the front |
| 107 // of the segment chain. Returns the new segment. | 104 // of the segment chain. Returns the new segment. |
| 108 inline Segment* NewSegment(size_t size); | 105 inline Segment* NewSegment(size_t size); |
| 109 | 106 |
| 110 // Deletes the given segment. Does not touch the segment chain. | |
| 111 inline void DeleteSegment(Segment* segment, size_t size); | |
| 112 | |
| 113 // The free region in the current (front) segment is represented as | 107 // The free region in the current (front) segment is represented as |
| 114 // the half-open interval [position, limit). The 'position' variable | 108 // the half-open interval [position, limit). The 'position' variable |
| 115 // is guaranteed to be aligned as dictated by kAlignment. | 109 // is guaranteed to be aligned as dictated by kAlignment. |
| 116 Address position_; | 110 Address position_; |
| 117 Address limit_; | 111 Address limit_; |
| 118 | 112 |
| 119 base::AccountingAllocator* allocator_; | 113 AccountingAllocator* allocator_; |
| 120 | 114 |
| 121 Segment* segment_head_; | 115 Segment* segment_head_; |
| 122 }; | 116 }; |
| 123 | 117 |
| 124 | |
| 125 // ZoneObject is an abstraction that helps define classes of objects | 118 // ZoneObject is an abstraction that helps define classes of objects |
| 126 // allocated in the Zone. Use it as a base class; see ast.h. | 119 // allocated in the Zone. Use it as a base class; see ast.h. |
| 127 class ZoneObject { | 120 class ZoneObject { |
| 128 public: | 121 public: |
| 129 // Allocate a new ZoneObject of 'size' bytes in the Zone. | 122 // Allocate a new ZoneObject of 'size' bytes in the Zone. |
| 130 void* operator new(size_t size, Zone* zone) { return zone->New(size); } | 123 void* operator new(size_t size, Zone* zone) { return zone->New(size); } |
| 131 | 124 |
| 132 // Ideally, the delete operator should be private instead of | 125 // Ideally, the delete operator should be private instead of |
| 133 // public, but unfortunately the compiler sometimes synthesizes | 126 // public, but unfortunately the compiler sometimes synthesizes |
| 134 // (unused) destructors for classes derived from ZoneObject, which | 127 // (unused) destructors for classes derived from ZoneObject, which |
| 135 // require the operator to be visible. MSVC requires the delete | 128 // require the operator to be visible. MSVC requires the delete |
| 136 // operator to be public. | 129 // operator to be public. |
| 137 | 130 |
| 138 // ZoneObjects should never be deleted individually; use | 131 // ZoneObjects should never be deleted individually; use |
| 139 // Zone::DeleteAll() to delete all zone objects in one go. | 132 // Zone::DeleteAll() to delete all zone objects in one go. |
| 140 void operator delete(void*, size_t) { UNREACHABLE(); } | 133 void operator delete(void*, size_t) { UNREACHABLE(); } |
| 141 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } | 134 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } |
| 142 }; | 135 }; |
| 143 | 136 |
| 144 | |
| 145 // The ZoneScope is used to automatically call DeleteAll() on a | 137 // The ZoneScope is used to automatically call DeleteAll() on a |
| 146 // Zone when the ZoneScope is destroyed (i.e. goes out of scope) | 138 // Zone when the ZoneScope is destroyed (i.e. goes out of scope) |
| 147 class ZoneScope final { | 139 class ZoneScope final { |
| 148 public: | 140 public: |
| 149 explicit ZoneScope(Zone* zone) : zone_(zone) { } | 141 explicit ZoneScope(Zone* zone) : zone_(zone) {} |
| 150 ~ZoneScope() { zone_->DeleteAll(); } | 142 ~ZoneScope() { zone_->DeleteAll(); } |
| 151 | 143 |
| 152 Zone* zone() const { return zone_; } | 144 Zone* zone() const { return zone_; } |
| 153 | 145 |
| 154 private: | 146 private: |
| 155 Zone* zone_; | 147 Zone* zone_; |
| 156 }; | 148 }; |
| 157 | 149 |
| 158 | |
| 159 // The ZoneAllocationPolicy is used to specialize generic data | 150 // The ZoneAllocationPolicy is used to specialize generic data |
| 160 // structures to allocate themselves and their elements in the Zone. | 151 // structures to allocate themselves and their elements in the Zone. |
| 161 class ZoneAllocationPolicy final { | 152 class ZoneAllocationPolicy final { |
| 162 public: | 153 public: |
| 163 explicit ZoneAllocationPolicy(Zone* zone) : zone_(zone) { } | 154 explicit ZoneAllocationPolicy(Zone* zone) : zone_(zone) {} |
| 164 void* New(size_t size) { return zone()->New(size); } | 155 void* New(size_t size) { return zone()->New(size); } |
| 165 static void Delete(void* pointer) {} | 156 static void Delete(void* pointer) {} |
| 166 Zone* zone() const { return zone_; } | 157 Zone* zone() const { return zone_; } |
| 167 | 158 |
| 168 private: | 159 private: |
| 169 Zone* zone_; | 160 Zone* zone_; |
| 170 }; | 161 }; |
| 171 | 162 |
| 172 | |
| 173 // ZoneLists are growable lists with constant-time access to the | 163 // ZoneLists are growable lists with constant-time access to the |
| 174 // elements. The list itself and all its elements are allocated in the | 164 // elements. The list itself and all its elements are allocated in the |
| 175 // Zone. ZoneLists cannot be deleted individually; you can delete all | 165 // Zone. ZoneLists cannot be deleted individually; you can delete all |
| 176 // objects in the Zone by calling Zone::DeleteAll(). | 166 // objects in the Zone by calling Zone::DeleteAll(). |
| 177 template <typename T> | 167 template <typename T> |
| 178 class ZoneList final : public List<T, ZoneAllocationPolicy> { | 168 class ZoneList final : public List<T, ZoneAllocationPolicy> { |
| 179 public: | 169 public: |
| 180 // Construct a new ZoneList with the given capacity; the length is | 170 // Construct a new ZoneList with the given capacity; the length is |
| 181 // always zero. The capacity must be non-negative. | 171 // always zero. The capacity must be non-negative. |
| 182 ZoneList(int capacity, Zone* zone) | 172 ZoneList(int capacity, Zone* zone) |
| 183 : List<T, ZoneAllocationPolicy>(capacity, ZoneAllocationPolicy(zone)) { } | 173 : List<T, ZoneAllocationPolicy>(capacity, ZoneAllocationPolicy(zone)) {} |
| 184 | 174 |
| 185 void* operator new(size_t size, Zone* zone) { return zone->New(size); } | 175 void* operator new(size_t size, Zone* zone) { return zone->New(size); } |
| 186 | 176 |
| 187 // Construct a new ZoneList by copying the elements of the given ZoneList. | 177 // Construct a new ZoneList by copying the elements of the given ZoneList. |
| 188 ZoneList(const ZoneList<T>& other, Zone* zone) | 178 ZoneList(const ZoneList<T>& other, Zone* zone) |
| 189 : List<T, ZoneAllocationPolicy>(other.length(), | 179 : List<T, ZoneAllocationPolicy>(other.length(), |
| 190 ZoneAllocationPolicy(zone)) { | 180 ZoneAllocationPolicy(zone)) { |
| 191 AddAll(other, zone); | 181 AddAll(other, zone); |
| 192 } | 182 } |
| 193 | 183 |
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| 215 } | 205 } |
| 216 void Initialize(int capacity, Zone* zone) { | 206 void Initialize(int capacity, Zone* zone) { |
| 217 List<T, ZoneAllocationPolicy>::Initialize(capacity, | 207 List<T, ZoneAllocationPolicy>::Initialize(capacity, |
| 218 ZoneAllocationPolicy(zone)); | 208 ZoneAllocationPolicy(zone)); |
| 219 } | 209 } |
| 220 | 210 |
| 221 void operator delete(void* pointer) { UNREACHABLE(); } | 211 void operator delete(void* pointer) { UNREACHABLE(); } |
| 222 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } | 212 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } |
| 223 }; | 213 }; |
| 224 | 214 |
| 225 | |
| 226 // A zone splay tree. The config type parameter encapsulates the | 215 // A zone splay tree. The config type parameter encapsulates the |
| 227 // different configurations of a concrete splay tree (see splay-tree.h). | 216 // different configurations of a concrete splay tree (see splay-tree.h). |
| 228 // The tree itself and all its elements are allocated in the Zone. | 217 // The tree itself and all its elements are allocated in the Zone. |
| 229 template <typename Config> | 218 template <typename Config> |
| 230 class ZoneSplayTree final : public SplayTree<Config, ZoneAllocationPolicy> { | 219 class ZoneSplayTree final : public SplayTree<Config, ZoneAllocationPolicy> { |
| 231 public: | 220 public: |
| 232 explicit ZoneSplayTree(Zone* zone) | 221 explicit ZoneSplayTree(Zone* zone) |
| 233 : SplayTree<Config, ZoneAllocationPolicy>(ZoneAllocationPolicy(zone)) {} | 222 : SplayTree<Config, ZoneAllocationPolicy>(ZoneAllocationPolicy(zone)) {} |
| 234 ~ZoneSplayTree() { | 223 ~ZoneSplayTree() { |
| 235 // Reset the root to avoid unneeded iteration over all tree nodes | 224 // Reset the root to avoid unneeded iteration over all tree nodes |
| 236 // in the destructor. For a zone-allocated tree, nodes will be | 225 // in the destructor. For a zone-allocated tree, nodes will be |
| 237 // freed by the Zone. | 226 // freed by the Zone. |
| 238 SplayTree<Config, ZoneAllocationPolicy>::ResetRoot(); | 227 SplayTree<Config, ZoneAllocationPolicy>::ResetRoot(); |
| 239 } | 228 } |
| 240 | 229 |
| 241 void* operator new(size_t size, Zone* zone) { return zone->New(size); } | 230 void* operator new(size_t size, Zone* zone) { return zone->New(size); } |
| 242 | 231 |
| 243 void operator delete(void* pointer) { UNREACHABLE(); } | 232 void operator delete(void* pointer) { UNREACHABLE(); } |
| 244 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } | 233 void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); } |
| 245 }; | 234 }; |
| 246 | 235 |
| 247 typedef base::TemplateHashMapImpl<ZoneAllocationPolicy> ZoneHashMap; | 236 typedef base::TemplateHashMapImpl<ZoneAllocationPolicy> ZoneHashMap; |
| 248 | 237 |
| 249 } // namespace internal | 238 } // namespace internal |
| 250 } // namespace v8 | 239 } // namespace v8 |
| 251 | 240 |
| 252 #endif // V8_ZONE_H_ | 241 #endif // V8_ZONE_H_ |
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