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1 // Copyright 2017 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_INVALIDATED_SLOTS_H_
6 #define V8_HEAP_INVALIDATED_SLOTS_H_
7 
8 #include <set>
9 #include <stack>
10 
11 #include "src/base/atomic-utils.h"
12 #include "src/heap/memory-chunk-layout.h"
13 #include "src/objects/heap-object.h"
14 #include "src/utils/allocation.h"
15 #include "src/utils/utils.h"
16 
17 namespace v8 {
18 namespace internal {
19 
20 // This data structure stores objects that went through object layout change
21 // that potentially invalidates slots recorded concurrently. The second part
22 // of each element is the size of the corresponding object before the layout
23 // change.
24 using InvalidatedSlots = std::set<HeapObject, Object::Comparer>;
25 
26 // This class provides IsValid predicate that takes into account the set
27 // of invalidated objects in the given memory chunk.
28 // The sequence of queried slot must be non-decreasing. This allows fast
29 // implementation with complexity O(m*log(m) + n), where
30 // m is the number of invalidated objects in the memory chunk.
31 // n is the number of IsValid queries.
32 class V8_EXPORT_PRIVATE InvalidatedSlotsFilter {
33  public:
34   static InvalidatedSlotsFilter OldToOld(MemoryChunk* chunk);
35   static InvalidatedSlotsFilter OldToNew(MemoryChunk* chunk);
36 
37   inline bool IsValid(Address slot);
38 
39  private:
40   explicit InvalidatedSlotsFilter(MemoryChunk* chunk,
41                                   InvalidatedSlots* invalidated_slots,
42                                   RememberedSetType remembered_set_type);
43 
44   InvalidatedSlots::const_iterator iterator_;
45   InvalidatedSlots::const_iterator iterator_end_;
46   Address sentinel_;
47   Address invalidated_start_;
48   Address next_invalidated_start_;
49   int invalidated_size_;
50   InvalidatedSlots empty_;
51 #ifdef DEBUG
52   Address last_slot_;
53   RememberedSetType remembered_set_type_;
54 #endif
55 
56  private:
57   inline void NextInvalidatedObject();
58 };
59 
60 class V8_EXPORT_PRIVATE InvalidatedSlotsCleanup {
61  public:
62   static InvalidatedSlotsCleanup OldToNew(MemoryChunk* chunk);
63   static InvalidatedSlotsCleanup NoCleanup(MemoryChunk* chunk);
64 
65   explicit InvalidatedSlotsCleanup(MemoryChunk* chunk,
66                                    InvalidatedSlots* invalidated_slots);
67 
68   inline void Free(Address free_start, Address free_end);
69 
70  private:
71   InvalidatedSlots::iterator iterator_;
72   InvalidatedSlots::iterator iterator_end_;
73   InvalidatedSlots* invalidated_slots_;
74   InvalidatedSlots empty_;
75 
76   Address sentinel_;
77   Address invalidated_start_;
78 
79   inline void NextInvalidatedObject();
80 #ifdef DEBUG
81   Address last_free_;
82 #endif
83 };
84 
85 }  // namespace internal
86 }  // namespace v8
87 
88 #endif  // V8_HEAP_INVALIDATED_SLOTS_H_
89