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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
|
/*
* Copyright (C) 2023 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "Structure.h"
#include <wtf/TZoneMalloc.h>
namespace JSC {
DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(MegamorphicCache);
class MegamorphicCache {
WTF_MAKE_TZONE_ALLOCATED(MegamorphicCache);
WTF_MAKE_NONCOPYABLE(MegamorphicCache);
public:
static constexpr uint32_t loadCachePrimarySize = 2048;
static constexpr uint32_t loadCacheSecondarySize = 512;
static_assert(hasOneBitSet(loadCachePrimarySize), "size should be a power of two.");
static_assert(hasOneBitSet(loadCacheSecondarySize), "size should be a power of two.");
static constexpr uint32_t loadCachePrimaryMask = loadCachePrimarySize - 1;
static constexpr uint32_t loadCacheSecondaryMask = loadCacheSecondarySize - 1;
static constexpr uint32_t storeCachePrimarySize = 2048;
static constexpr uint32_t storeCacheSecondarySize = 512;
static_assert(hasOneBitSet(storeCachePrimarySize), "size should be a power of two.");
static_assert(hasOneBitSet(storeCacheSecondarySize), "size should be a power of two.");
static constexpr uint32_t storeCachePrimaryMask = storeCachePrimarySize - 1;
static constexpr uint32_t storeCacheSecondaryMask = storeCacheSecondarySize - 1;
static constexpr uint32_t hasCachePrimarySize = 512;
static constexpr uint32_t hasCacheSecondarySize = 128;
static_assert(hasOneBitSet(hasCachePrimarySize), "size should be a power of two.");
static_assert(hasOneBitSet(hasCacheSecondarySize), "size should be a power of two.");
static constexpr uint32_t hasCachePrimaryMask = hasCachePrimarySize - 1;
static constexpr uint32_t hasCacheSecondaryMask = hasCacheSecondarySize - 1;
static constexpr uint16_t invalidEpoch = 0;
static constexpr PropertyOffset maxOffset = UINT16_MAX;
struct LoadEntry {
static constexpr ptrdiff_t offsetOfUid() { return OBJECT_OFFSETOF(LoadEntry, m_uid); }
static constexpr ptrdiff_t offsetOfStructureID() { return OBJECT_OFFSETOF(LoadEntry, m_structureID); }
static constexpr ptrdiff_t offsetOfEpoch() { return OBJECT_OFFSETOF(LoadEntry, m_epoch); }
static constexpr ptrdiff_t offsetOfOffset() { return OBJECT_OFFSETOF(LoadEntry, m_offset); }
static constexpr ptrdiff_t offsetOfHolder() { return OBJECT_OFFSETOF(LoadEntry, m_holder); }
void initAsMiss(StructureID structureID, UniquedStringImpl* uid, uint16_t epoch)
{
m_uid = uid;
m_structureID = structureID;
m_epoch = epoch;
m_offset = 0;
m_holder = nullptr;
}
void initAsHit(StructureID structureID, UniquedStringImpl* uid, uint16_t epoch, JSCell* holder, uint16_t offset, bool ownProperty)
{
m_uid = uid;
m_structureID = structureID;
m_epoch = epoch;
m_offset = offset;
m_holder = (ownProperty) ? JSCell::seenMultipleCalleeObjects() : holder;
}
RefPtr<UniquedStringImpl> m_uid;
StructureID m_structureID { };
uint16_t m_epoch { invalidEpoch };
uint16_t m_offset { 0 };
JSCell* m_holder { nullptr };
};
struct StoreEntry {
static constexpr ptrdiff_t offsetOfUid() { return OBJECT_OFFSETOF(StoreEntry, m_uid); }
static constexpr ptrdiff_t offsetOfOldStructureID() { return OBJECT_OFFSETOF(StoreEntry, m_oldStructureID); }
static constexpr ptrdiff_t offsetOfNewStructureID() { return OBJECT_OFFSETOF(StoreEntry, m_newStructureID); }
static constexpr ptrdiff_t offsetOfEpoch() { return OBJECT_OFFSETOF(StoreEntry, m_epoch); }
static constexpr ptrdiff_t offsetOfOffset() { return OBJECT_OFFSETOF(StoreEntry, m_offset); }
static constexpr ptrdiff_t offsetOfReallocating() { return OBJECT_OFFSETOF(StoreEntry, m_reallocating); }
void init(StructureID oldStructureID, StructureID newStructureID, UniquedStringImpl* uid, uint16_t epoch, uint16_t offset, bool reallocating)
{
m_uid = uid;
m_oldStructureID = oldStructureID;
m_newStructureID = newStructureID;
m_epoch = epoch;
m_offset = offset;
m_reallocating = reallocating;
}
RefPtr<UniquedStringImpl> m_uid;
StructureID m_oldStructureID { };
StructureID m_newStructureID { };
uint16_t m_epoch { invalidEpoch };
uint16_t m_offset { 0 };
uint8_t m_reallocating { 0 };
};
struct HasEntry {
static constexpr ptrdiff_t offsetOfUid() { return OBJECT_OFFSETOF(HasEntry, m_uid); }
static constexpr ptrdiff_t offsetOfStructureID() { return OBJECT_OFFSETOF(HasEntry, m_structureID); }
static constexpr ptrdiff_t offsetOfEpoch() { return OBJECT_OFFSETOF(HasEntry, m_epoch); }
static constexpr ptrdiff_t offsetOfResult() { return OBJECT_OFFSETOF(HasEntry, m_result); }
void init(StructureID structureID, UniquedStringImpl* uid, uint16_t epoch, bool result)
{
m_uid = uid;
m_structureID = structureID;
m_epoch = epoch;
m_result = !!result;
}
RefPtr<UniquedStringImpl> m_uid;
StructureID m_structureID { };
uint16_t m_epoch { invalidEpoch };
uint16_t m_result { false };
};
static constexpr ptrdiff_t offsetOfLoadCachePrimaryEntries() { return OBJECT_OFFSETOF(MegamorphicCache, m_loadCachePrimaryEntries); }
static constexpr ptrdiff_t offsetOfLoadCacheSecondaryEntries() { return OBJECT_OFFSETOF(MegamorphicCache, m_loadCacheSecondaryEntries); }
static constexpr ptrdiff_t offsetOfStoreCachePrimaryEntries() { return OBJECT_OFFSETOF(MegamorphicCache, m_storeCachePrimaryEntries); }
static constexpr ptrdiff_t offsetOfStoreCacheSecondaryEntries() { return OBJECT_OFFSETOF(MegamorphicCache, m_storeCacheSecondaryEntries); }
static constexpr ptrdiff_t offsetOfHasCachePrimaryEntries() { return OBJECT_OFFSETOF(MegamorphicCache, m_hasCachePrimaryEntries); }
static constexpr ptrdiff_t offsetOfHasCacheSecondaryEntries() { return OBJECT_OFFSETOF(MegamorphicCache, m_hasCacheSecondaryEntries); }
static constexpr ptrdiff_t offsetOfEpoch() { return OBJECT_OFFSETOF(MegamorphicCache, m_epoch); }
MegamorphicCache() = default;
#if CPU(ADDRESS64) && !ENABLE(STRUCTURE_ID_WITH_SHIFT)
// Because Structure is allocated with 16-byte alignment, we should assume that StructureID's lower 4 bits are zeros.
static constexpr unsigned structureIDHashShift1 = 4;
#else
// When using STRUCTURE_ID_WITH_SHIFT, all bits can be different. Thus we do not need to shift the first level.
static constexpr unsigned structureIDHashShift1 = 0;
#endif
static constexpr unsigned structureIDHashShift2 = structureIDHashShift1 + 11;
static constexpr unsigned structureIDHashShift3 = structureIDHashShift1 + 9;
static constexpr unsigned structureIDHashShift4 = structureIDHashShift1 + 11;
static constexpr unsigned structureIDHashShift5 = structureIDHashShift1 + 9;
static constexpr unsigned structureIDHashShift6 = structureIDHashShift1 + 9;
static constexpr unsigned structureIDHashShift7 = structureIDHashShift1 + 7;
ALWAYS_INLINE static uint32_t primaryHash(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t sid = std::bit_cast<uint32_t>(structureID);
return ((sid >> structureIDHashShift1) ^ (sid >> structureIDHashShift2)) + uid->hash();
}
ALWAYS_INLINE static uint32_t secondaryHash(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t key = std::bit_cast<uint32_t>(structureID) + static_cast<uint32_t>(std::bit_cast<uintptr_t>(uid));
return key + (key >> structureIDHashShift3);
}
ALWAYS_INLINE static uint32_t storeCachePrimaryHash(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t sid = std::bit_cast<uint32_t>(structureID);
return ((sid >> structureIDHashShift1) ^ (sid >> structureIDHashShift4)) + uid->hash();
}
ALWAYS_INLINE static uint32_t storeCacheSecondaryHash(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t key = std::bit_cast<uint32_t>(structureID) + static_cast<uint32_t>(std::bit_cast<uintptr_t>(uid));
return key + (key >> structureIDHashShift5);
}
ALWAYS_INLINE static uint32_t hasCachePrimaryHash(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t sid = std::bit_cast<uint32_t>(structureID);
return ((sid >> structureIDHashShift1) ^ (sid >> structureIDHashShift6)) + uid->hash();
}
ALWAYS_INLINE static uint32_t hasCacheSecondaryHash(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t key = std::bit_cast<uint32_t>(structureID) + static_cast<uint32_t>(std::bit_cast<uintptr_t>(uid));
return key + (key >> structureIDHashShift7);
}
JS_EXPORT_PRIVATE void age(CollectionScope);
void initAsMiss(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t primaryIndex = MegamorphicCache::primaryHash(structureID, uid) & loadCachePrimaryMask;
auto& entry = m_loadCachePrimaryEntries[primaryIndex];
if (entry.m_epoch == m_epoch) {
uint32_t secondaryIndex = MegamorphicCache::secondaryHash(entry.m_structureID, entry.m_uid.get()) & loadCacheSecondaryMask;
m_loadCacheSecondaryEntries[secondaryIndex] = WTFMove(entry);
}
m_loadCachePrimaryEntries[primaryIndex].initAsMiss(structureID, uid, m_epoch);
}
void initAsHit(StructureID structureID, UniquedStringImpl* uid, JSCell* holder, uint16_t offset, bool ownProperty)
{
uint32_t primaryIndex = MegamorphicCache::primaryHash(structureID, uid) & loadCachePrimaryMask;
auto& entry = m_loadCachePrimaryEntries[primaryIndex];
if (entry.m_epoch == m_epoch) {
uint32_t secondaryIndex = MegamorphicCache::secondaryHash(entry.m_structureID, entry.m_uid.get()) & loadCacheSecondaryMask;
m_loadCacheSecondaryEntries[secondaryIndex] = WTFMove(entry);
}
m_loadCachePrimaryEntries[primaryIndex].initAsHit(structureID, uid, m_epoch, holder, offset, ownProperty);
}
void initAsTransition(StructureID oldStructureID, StructureID newStructureID, UniquedStringImpl* uid, uint16_t offset, bool reallocating)
{
uint32_t primaryIndex = MegamorphicCache::storeCachePrimaryHash(oldStructureID, uid) & storeCachePrimaryMask;
auto& entry = m_storeCachePrimaryEntries[primaryIndex];
if (entry.m_epoch == m_epoch) {
uint32_t secondaryIndex = MegamorphicCache::storeCacheSecondaryHash(entry.m_oldStructureID, entry.m_uid.get()) & storeCacheSecondaryMask;
m_storeCacheSecondaryEntries[secondaryIndex] = WTFMove(entry);
}
m_storeCachePrimaryEntries[primaryIndex].init(oldStructureID, newStructureID, uid, m_epoch, offset, reallocating);
}
void initAsReplace(StructureID structureID, UniquedStringImpl* uid, uint16_t offset)
{
uint32_t primaryIndex = MegamorphicCache::storeCachePrimaryHash(structureID, uid) & storeCachePrimaryMask;
auto& entry = m_storeCachePrimaryEntries[primaryIndex];
if (entry.m_epoch == m_epoch) {
uint32_t secondaryIndex = MegamorphicCache::storeCacheSecondaryHash(entry.m_oldStructureID, entry.m_uid.get()) & storeCacheSecondaryMask;
m_storeCacheSecondaryEntries[secondaryIndex] = WTFMove(entry);
}
m_storeCachePrimaryEntries[primaryIndex].init(structureID, structureID, uid, m_epoch, offset, false);
}
void initAsHasHit(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t primaryIndex = MegamorphicCache::hasCachePrimaryHash(structureID, uid) & hasCachePrimaryMask;
auto& entry = m_hasCachePrimaryEntries[primaryIndex];
if (entry.m_epoch == m_epoch) {
uint32_t secondaryIndex = MegamorphicCache::hasCacheSecondaryHash(entry.m_structureID, entry.m_uid.get()) & hasCacheSecondaryMask;
m_hasCacheSecondaryEntries[secondaryIndex] = WTFMove(entry);
}
m_hasCachePrimaryEntries[primaryIndex].init(structureID, uid, m_epoch, true);
}
void initAsHasMiss(StructureID structureID, UniquedStringImpl* uid)
{
uint32_t primaryIndex = MegamorphicCache::hasCachePrimaryHash(structureID, uid) & hasCachePrimaryMask;
auto& entry = m_hasCachePrimaryEntries[primaryIndex];
if (entry.m_epoch == m_epoch) {
uint32_t secondaryIndex = MegamorphicCache::hasCacheSecondaryHash(entry.m_structureID, entry.m_uid.get()) & hasCacheSecondaryMask;
m_hasCacheSecondaryEntries[secondaryIndex] = WTFMove(entry);
}
m_hasCachePrimaryEntries[primaryIndex].init(structureID, uid, m_epoch, false);
}
uint16_t epoch() const { return m_epoch; }
void bumpEpoch()
{
++m_epoch;
if (UNLIKELY(m_epoch == invalidEpoch))
clearEntries();
}
private:
JS_EXPORT_PRIVATE void clearEntries();
std::array<LoadEntry, loadCachePrimarySize> m_loadCachePrimaryEntries { };
std::array<LoadEntry, loadCacheSecondarySize> m_loadCacheSecondaryEntries { };
std::array<StoreEntry, storeCachePrimarySize> m_storeCachePrimaryEntries { };
std::array<StoreEntry, storeCacheSecondarySize> m_storeCacheSecondaryEntries { };
std::array<HasEntry, hasCachePrimarySize> m_hasCachePrimaryEntries { };
std::array<HasEntry, hasCacheSecondarySize> m_hasCacheSecondaryEntries { };
uint16_t m_epoch { 1 };
};
} // namespace JSC
|
