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.
5 #ifndef V8_HEAP_ARRAY_BUFFER_TRACKER_H_
6 #define V8_HEAP_ARRAY_BUFFER_TRACKER_H_
10 #include "src/globals.h"
15 // Forward declarations.
19 class ArrayBufferTracker {
21 explicit ArrayBufferTracker(Heap* heap) : heap_(heap) {}
22 ~ArrayBufferTracker();
24 inline Heap* heap() { return heap_; }
26 // The following methods are used to track raw C++ pointers to externally
27 // allocated memory used as backing store in live array buffers.
29 // A new ArrayBuffer was created with |data| as backing store.
30 void RegisterNew(JSArrayBuffer* buffer);
32 // The backing store |data| is no longer owned by V8.
33 void Unregister(JSArrayBuffer* buffer);
35 // A live ArrayBuffer was discovered during marking/scavenge.
36 void MarkLive(JSArrayBuffer* buffer);
38 // Frees all backing store pointers that weren't discovered in the previous
39 // marking or scavenge phase.
40 void FreeDead(bool from_scavenge);
42 // Prepare for a new scavenge phase. A new marking phase is implicitly
43 // prepared by finishing the previous one.
44 void PrepareDiscoveryInNewSpace();
46 // An ArrayBuffer moved from new space to old space.
47 void Promote(JSArrayBuffer* buffer);
52 // |live_array_buffers_| maps externally allocated memory used as backing
53 // store for ArrayBuffers to the length of the respective memory blocks.
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_;
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.
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_;
71 } // namespace internal
73 #endif // V8_HEAP_ARRAY_BUFFER_TRACKER_H_