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_HEAP_ARRAY_BUFFER_TRACKER_H_ 6 #define V8_HEAP_ARRAY_BUFFER_TRACKER_H_ 7 8 #include <map> 9 10 #include "src/globals.h" 11 12 namespace v8 { 13 namespace internal { 14 15 // Forward declarations. 16 class Heap; 17 class JSArrayBuffer; 18 19 class ArrayBufferTracker { 20 public: 21 explicit ArrayBufferTracker(Heap* heap) : heap_(heap) {} 22 ~ArrayBufferTracker(); 23 24 inline Heap* heap() { return heap_; } 25 26 // The following methods are used to track raw C++ pointers to externally 27 // allocated memory used as backing store in live array buffers. 28 29 // A new ArrayBuffer was created with |data| as backing store. 30 void RegisterNew(JSArrayBuffer* buffer); 31 32 // The backing store |data| is no longer owned by V8. 33 void Unregister(JSArrayBuffer* buffer); 34 35 // A live ArrayBuffer was discovered during marking/scavenge. 36 void MarkLive(JSArrayBuffer* buffer); 37 38 // Frees all backing store pointers that weren't discovered in the previous 39 // marking or scavenge phase. 40 void FreeDead(bool from_scavenge); 41 42 // Prepare for a new scavenge phase. A new marking phase is implicitly 43 // prepared by finishing the previous one. 44 void PrepareDiscoveryInNewSpace(); 45 46 // An ArrayBuffer moved from new space to old space. 47 void Promote(JSArrayBuffer* buffer); 48 49 private: 50 Heap* heap_; 51 52 // |live_array_buffers_| maps externally allocated memory used as backing 53 // store for ArrayBuffers to the length of the respective memory blocks. 54 // 55 // At the beginning of mark/compact, |not_yet_discovered_array_buffers_| is 56 // a copy of |live_array_buffers_| and we remove pointers as we discover live 57 // ArrayBuffer objects during marking. At the end of mark/compact, the 58 // remaining memory blocks can be freed. 59 std::map<void*, size_t> live_array_buffers_; 60 std::map<void*, size_t> not_yet_discovered_array_buffers_; 61 62 // To be able to free memory held by ArrayBuffers during scavenge as well, we 63 // have a separate list of allocated memory held by ArrayBuffers in new space. 64 // 65 // Since mark/compact also evacuates the new space, all pointers in the 66 // |live_array_buffers_for_scavenge_| list are also in the 67 // |live_array_buffers_| list. 68 std::map<void*, size_t> live_array_buffers_for_scavenge_; 69 std::map<void*, size_t> not_yet_discovered_array_buffers_for_scavenge_; 70 }; 71 } // namespace internal 72 } // namespace v8 73 #endif // V8_HEAP_ARRAY_BUFFER_TRACKER_H_ 74
