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_UTILS_ADDRESS_MAP_H_
6 #define V8_UTILS_ADDRESS_MAP_H_
7
8 #include "src/base/hashmap.h"
9 #include "src/common/assert-scope.h"
10 #include "src/objects/heap-object.h"
11 #include "src/roots/roots.h"
12
13 namespace v8 {
14 namespace internal {
15
16 template <typename Type>
17 class PointerToIndexHashMap
18 : public base::TemplateHashMapImpl<uintptr_t, uint32_t,
19 base::KeyEqualityMatcher<intptr_t>,
20 base::DefaultAllocationPolicy> {
21 public:
22 using Entry = base::TemplateHashMapEntry<uintptr_t, uint32_t>;
23
Set(Type value,uint32_t index)24 inline void Set(Type value, uint32_t index) {
25 uintptr_t key = Key(value);
26 LookupOrInsert(key, Hash(key))->value = index;
27 }
28
Get(Type value)29 inline Maybe<uint32_t> Get(Type value) const {
30 uintptr_t key = Key(value);
31 Entry* entry = Lookup(key, Hash(key));
32 if (entry == nullptr) return Nothing<uint32_t>();
33 return Just(entry->value);
34 }
35
36 private:
37 static inline uintptr_t Key(Type value);
38
Hash(uintptr_t key)39 static uint32_t Hash(uintptr_t key) { return static_cast<uint32_t>(key); }
40 };
41
42 template <>
Key(Address value)43 inline uintptr_t PointerToIndexHashMap<Address>::Key(Address value) {
44 return static_cast<uintptr_t>(value);
45 }
46
47 template <>
Key(HeapObject value)48 inline uintptr_t PointerToIndexHashMap<HeapObject>::Key(HeapObject value) {
49 return value.ptr();
50 }
51
52 class AddressToIndexHashMap : public PointerToIndexHashMap<Address> {};
53 class HeapObjectToIndexHashMap : public PointerToIndexHashMap<HeapObject> {};
54
55 class RootIndexMap {
56 public:
57 explicit RootIndexMap(Isolate* isolate);
58 RootIndexMap(const RootIndexMap&) = delete;
59 RootIndexMap& operator=(const RootIndexMap&) = delete;
60
61 // Returns true on successful lookup and sets *|out_root_list|.
Lookup(HeapObject obj,RootIndex * out_root_list)62 bool Lookup(HeapObject obj, RootIndex* out_root_list) const {
63 Maybe<uint32_t> maybe_index = map_->Get(obj);
64 if (maybe_index.IsJust()) {
65 *out_root_list = static_cast<RootIndex>(maybe_index.FromJust());
66 return true;
67 }
68 return false;
69 }
70 bool Lookup(Address obj, RootIndex* out_root_list) const;
71
72 private:
73 HeapObjectToIndexHashMap* map_;
74 };
75
76 } // namespace internal
77 } // namespace v8
78
79 #endif // V8_UTILS_ADDRESS_MAP_H_
80