1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/v8.h"
#include "src/base/bits.h"
#include "src/ic/stub-cache.h"
#include "src/type-info.h"
namespace v8 {
namespace internal {
StubCache::StubCache(Isolate* isolate) : isolate_(isolate) {}
void StubCache::Initialize() {
DCHECK(base::bits::IsPowerOfTwo32(kPrimaryTableSize));
DCHECK(base::bits::IsPowerOfTwo32(kSecondaryTableSize));
Clear();
}
static Code::Flags CommonStubCacheChecks(Name* name, Map* map,
Code::Flags flags) {
flags = Code::RemoveTypeAndHolderFromFlags(flags);
// Validate that the name does not move on scavenge, and that we
// can use identity checks instead of structural equality checks.
DCHECK(!name->GetHeap()->InNewSpace(name));
DCHECK(name->IsUniqueName());
// The state bits are not important to the hash function because the stub
// cache only contains handlers. Make sure that the bits are the least
// significant so they will be the ones masked out.
DCHECK_EQ(Code::HANDLER, Code::ExtractKindFromFlags(flags));
STATIC_ASSERT((Code::ICStateField::kMask & 1) == 1);
// Make sure that the code type and cache holder are not included in the hash.
DCHECK(Code::ExtractTypeFromFlags(flags) == 0);
DCHECK(Code::ExtractCacheHolderFromFlags(flags) == 0);
return flags;
}
Code* StubCache::Set(Name* name, Map* map, Code* code) {
Code::Flags flags = CommonStubCacheChecks(name, map, code->flags());
// Compute the primary entry.
int primary_offset = PrimaryOffset(name, flags, map);
Entry* primary = entry(primary_, primary_offset);
Code* old_code = primary->value;
// If the primary entry has useful data in it, we retire it to the
// secondary cache before overwriting it.
if (old_code != isolate_->builtins()->builtin(Builtins::kIllegal)) {
Map* old_map = primary->map;
Code::Flags old_flags =
Code::RemoveTypeAndHolderFromFlags(old_code->flags());
int seed = PrimaryOffset(primary->key, old_flags, old_map);
int secondary_offset = SecondaryOffset(primary->key, old_flags, seed);
Entry* secondary = entry(secondary_, secondary_offset);
*secondary = *primary;
}
// Update primary cache.
primary->key = name;
primary->value = code;
primary->map = map;
isolate()->counters()->megamorphic_stub_cache_updates()->Increment();
return code;
}
Code* StubCache::Get(Name* name, Map* map, Code::Flags flags) {
flags = CommonStubCacheChecks(name, map, flags);
int primary_offset = PrimaryOffset(name, flags, map);
Entry* primary = entry(primary_, primary_offset);
if (primary->key == name && primary->map == map) {
return primary->value;
}
int secondary_offset = SecondaryOffset(name, flags, primary_offset);
Entry* secondary = entry(secondary_, secondary_offset);
if (secondary->key == name && secondary->map == map) {
return secondary->value;
}
return NULL;
}
void StubCache::Clear() {
Code* empty = isolate_->builtins()->builtin(Builtins::kIllegal);
for (int i = 0; i < kPrimaryTableSize; i++) {
primary_[i].key = isolate()->heap()->empty_string();
primary_[i].map = NULL;
primary_[i].value = empty;
}
for (int j = 0; j < kSecondaryTableSize; j++) {
secondary_[j].key = isolate()->heap()->empty_string();
secondary_[j].map = NULL;
secondary_[j].value = empty;
}
}
void StubCache::CollectMatchingMaps(SmallMapList* types, Handle<Name> name,
Code::Flags flags,
Handle<Context> native_context,
Zone* zone) {
for (int i = 0; i < kPrimaryTableSize; i++) {
if (primary_[i].key == *name) {
Map* map = primary_[i].map;
// Map can be NULL, if the stub is constant function call
// with a primitive receiver.
if (map == NULL) continue;
int offset = PrimaryOffset(*name, flags, map);
if (entry(primary_, offset) == &primary_[i] &&
TypeFeedbackOracle::IsRelevantFeedback(map, *native_context)) {
types->AddMapIfMissing(Handle<Map>(map), zone);
}
}
}
for (int i = 0; i < kSecondaryTableSize; i++) {
if (secondary_[i].key == *name) {
Map* map = secondary_[i].map;
// Map can be NULL, if the stub is constant function call
// with a primitive receiver.
if (map == NULL) continue;
// Lookup in primary table and skip duplicates.
int primary_offset = PrimaryOffset(*name, flags, map);
// Lookup in secondary table and add matches.
int offset = SecondaryOffset(*name, flags, primary_offset);
if (entry(secondary_, offset) == &secondary_[i] &&
TypeFeedbackOracle::IsRelevantFeedback(map, *native_context)) {
types->AddMapIfMissing(Handle<Map>(map), zone);
}
}
}
}
}
} // namespace v8::internal
|
