1/*
2 * Copyright (C) 2007, 2008, 2012-2015 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#pragma once
30
31#include "ConcurrentJSLock.h"
32#include "ConstantMode.h"
33#include "InferredValue.h"
34#include "JSObject.h"
35#include "ScopedArgumentsTable.h"
36#include "TypeLocation.h"
37#include "VarOffset.h"
38#include "Watchpoint.h"
39#include <memory>
40#include <wtf/HashTraits.h>
41#include <wtf/text/UniquedStringImpl.h>
42
43namespace JSC {
44
45class SymbolTable;
46
47static ALWAYS_INLINE int missingSymbolMarker() { return std::numeric_limits<int>::max(); }
48
49// The bit twiddling in this class assumes that every register index is a
50// reasonably small positive or negative number, and therefore has its high
51// four bits all set or all unset.
52
53// In addition to implementing semantics-mandated variable attributes and
54// implementation-mandated variable indexing, this class also implements
55// watchpoints to be used for JIT optimizations. Because watchpoints are
56// meant to be relatively rare, this class optimizes heavily for the case
57// that they are not being used. To that end, this class uses the thin-fat
58// idiom: either it is thin, in which case it contains an in-place encoded
59// word that consists of attributes, the index, and a bit saying that it is
60// thin; or it is fat, in which case it contains a pointer to a malloc'd
61// data structure and a bit saying that it is fat. The malloc'd data
62// structure will be malloced a second time upon copy, to preserve the
63// property that in-place edits to SymbolTableEntry do not manifest in any
64// copies. However, the malloc'd FatEntry data structure contains a ref-
65// counted pointer to a shared WatchpointSet. Thus, in-place edits of the
66// WatchpointSet will manifest in all copies. Here's a picture:
67//
68// SymbolTableEntry --> FatEntry --> WatchpointSet
69//
70// If you make a copy of a SymbolTableEntry, you will have:
71//
72// original: SymbolTableEntry --> FatEntry --> WatchpointSet
73// copy: SymbolTableEntry --> FatEntry -----^
74
75struct SymbolTableEntry {
76 friend class CachedSymbolTableEntry;
77
78private:
79 static VarOffset varOffsetFromBits(intptr_t bits)
80 {
81 VarKind kind;
82 intptr_t kindBits = bits & KindBitsMask;
83 if (kindBits <= UnwatchableScopeKindBits)
84 kind = VarKind::Scope;
85 else if (kindBits == StackKindBits)
86 kind = VarKind::Stack;
87 else
88 kind = VarKind::DirectArgument;
89 return VarOffset::assemble(kind, static_cast<int>(bits >> FlagBits));
90 }
91
92 static ScopeOffset scopeOffsetFromBits(intptr_t bits)
93 {
94 ASSERT((bits & KindBitsMask) <= UnwatchableScopeKindBits);
95 return ScopeOffset(static_cast<int>(bits >> FlagBits));
96 }
97
98public:
99
100 // Use the SymbolTableEntry::Fast class, either via implicit cast or by calling
101 // getFast(), when you (1) only care about isNull(), getIndex(), and isReadOnly(),
102 // and (2) you are in a hot path where you need to minimize the number of times
103 // that you branch on isFat() when getting the bits().
104 class Fast {
105 public:
106 Fast()
107 : m_bits(SlimFlag)
108 {
109 }
110
111 ALWAYS_INLINE Fast(const SymbolTableEntry& entry)
112 : m_bits(entry.bits())
113 {
114 }
115
116 bool isNull() const
117 {
118 return !(m_bits & ~SlimFlag);
119 }
120
121 VarOffset varOffset() const
122 {
123 return varOffsetFromBits(m_bits);
124 }
125
126 // Asserts if the offset is anything but a scope offset. This structures the assertions
127 // in a way that may result in better code, even in release, than doing
128 // varOffset().scopeOffset().
129 ScopeOffset scopeOffset() const
130 {
131 return scopeOffsetFromBits(m_bits);
132 }
133
134 bool isReadOnly() const
135 {
136 return m_bits & ReadOnlyFlag;
137 }
138
139 bool isDontEnum() const
140 {
141 return m_bits & DontEnumFlag;
142 }
143
144 unsigned getAttributes() const
145 {
146 unsigned attributes = 0;
147 if (isReadOnly())
148 attributes |= PropertyAttribute::ReadOnly;
149 if (isDontEnum())
150 attributes |= PropertyAttribute::DontEnum;
151 return attributes;
152 }
153
154 bool isFat() const
155 {
156 return !(m_bits & SlimFlag);
157 }
158
159 private:
160 friend struct SymbolTableEntry;
161 intptr_t m_bits;
162 };
163
164 SymbolTableEntry()
165 : m_bits(SlimFlag)
166 {
167 }
168
169 SymbolTableEntry(VarOffset offset)
170 : m_bits(SlimFlag)
171 {
172 ASSERT(isValidVarOffset(offset));
173 pack(offset, true, false, false);
174 }
175
176 SymbolTableEntry(VarOffset offset, unsigned attributes)
177 : m_bits(SlimFlag)
178 {
179 ASSERT(isValidVarOffset(offset));
180 pack(offset, true, attributes & PropertyAttribute::ReadOnly, attributes & PropertyAttribute::DontEnum);
181 }
182
183 ~SymbolTableEntry()
184 {
185 freeFatEntry();
186 }
187
188 SymbolTableEntry(const SymbolTableEntry& other)
189 : m_bits(SlimFlag)
190 {
191 *this = other;
192 }
193
194 SymbolTableEntry& operator=(const SymbolTableEntry& other)
195 {
196 if (UNLIKELY(other.isFat()))
197 return copySlow(other);
198 freeFatEntry();
199 m_bits = other.m_bits;
200 return *this;
201 }
202
203 SymbolTableEntry(SymbolTableEntry&& other)
204 : m_bits(SlimFlag)
205 {
206 swap(other);
207 }
208
209 SymbolTableEntry& operator=(SymbolTableEntry&& other)
210 {
211 swap(other);
212 return *this;
213 }
214
215 void swap(SymbolTableEntry& other)
216 {
217 std::swap(m_bits, other.m_bits);
218 }
219
220 bool isNull() const
221 {
222 return !(bits() & ~SlimFlag);
223 }
224
225 VarOffset varOffset() const
226 {
227 return varOffsetFromBits(bits());
228 }
229
230 bool isWatchable() const
231 {
232 return (m_bits & KindBitsMask) == ScopeKindBits && VM::canUseJIT();
233 }
234
235 // Asserts if the offset is anything but a scope offset. This structures the assertions
236 // in a way that may result in better code, even in release, than doing
237 // varOffset().scopeOffset().
238 ScopeOffset scopeOffset() const
239 {
240 return scopeOffsetFromBits(bits());
241 }
242
243 ALWAYS_INLINE Fast getFast() const
244 {
245 return Fast(*this);
246 }
247
248 ALWAYS_INLINE Fast getFast(bool& wasFat) const
249 {
250 Fast result;
251 wasFat = isFat();
252 if (wasFat)
253 result.m_bits = fatEntry()->m_bits | SlimFlag;
254 else
255 result.m_bits = m_bits;
256 return result;
257 }
258
259 unsigned getAttributes() const
260 {
261 return getFast().getAttributes();
262 }
263
264 void setAttributes(unsigned attributes)
265 {
266 pack(varOffset(), isWatchable(), attributes & PropertyAttribute::ReadOnly, attributes & PropertyAttribute::DontEnum);
267 }
268
269 bool isReadOnly() const
270 {
271 return bits() & ReadOnlyFlag;
272 }
273
274 ConstantMode constantMode() const
275 {
276 return modeForIsConstant(isReadOnly());
277 }
278
279 bool isDontEnum() const
280 {
281 return bits() & DontEnumFlag;
282 }
283
284 void disableWatching(VM& vm)
285 {
286 if (WatchpointSet* set = watchpointSet())
287 set->invalidate(vm, "Disabling watching in symbol table");
288 if (varOffset().isScope())
289 pack(varOffset(), false, isReadOnly(), isDontEnum());
290 }
291
292 void prepareToWatch();
293
294 // This watchpoint set is initialized clear, and goes through the following state transitions:
295 //
296 // First write to this var, in any scope that has this symbol table: Clear->IsWatched.
297 //
298 // Second write to this var, in any scope that has this symbol table: IsWatched->IsInvalidated.
299 //
300 // We ensure that we touch the set (i.e. trigger its state transition) after we do the write. This
301 // means that if you're in the compiler thread, and you:
302 //
303 // 1) Observe that the set IsWatched and commit to adding your watchpoint.
304 // 2) Load a value from any scope that has this watchpoint set.
305 //
306 // Then you can be sure that that value is either going to be the correct value for that var forever,
307 // or the watchpoint set will invalidate and you'll get fired.
308 //
309 // It's possible to write a program that first creates multiple scopes with the same var, and then
310 // initializes that var in just one of them. This means that a compilation could constant-fold to one
311 // of the scopes that still has an undefined value for this variable. That's fine, because at that
312 // point any write to any of the instances of that variable would fire the watchpoint.
313 //
314 // Note that watchpointSet() returns nullptr if JIT is disabled.
315 WatchpointSet* watchpointSet()
316 {
317 if (!isFat())
318 return nullptr;
319 return fatEntry()->m_watchpoints.get();
320 }
321
322private:
323 static const intptr_t SlimFlag = 0x1;
324 static const intptr_t ReadOnlyFlag = 0x2;
325 static const intptr_t DontEnumFlag = 0x4;
326 static const intptr_t NotNullFlag = 0x8;
327 static const intptr_t KindBitsMask = 0x30;
328 static const intptr_t ScopeKindBits = 0x00;
329 static const intptr_t UnwatchableScopeKindBits = 0x10;
330 static const intptr_t StackKindBits = 0x20;
331 static const intptr_t DirectArgumentKindBits = 0x30;
332 static const intptr_t FlagBits = 6;
333
334 class FatEntry {
335 WTF_MAKE_FAST_ALLOCATED;
336 public:
337 FatEntry(intptr_t bits)
338 : m_bits(bits & ~SlimFlag)
339 {
340 }
341
342 intptr_t m_bits; // always has FatFlag set and exactly matches what the bits would have been if this wasn't fat.
343
344 RefPtr<WatchpointSet> m_watchpoints;
345 };
346
347 SymbolTableEntry& copySlow(const SymbolTableEntry&);
348 JS_EXPORT_PRIVATE void notifyWriteSlow(VM&, JSValue, const FireDetail&);
349
350 bool isFat() const
351 {
352 return !(m_bits & SlimFlag);
353 }
354
355 const FatEntry* fatEntry() const
356 {
357 ASSERT(isFat());
358 return bitwise_cast<const FatEntry*>(m_bits);
359 }
360
361 FatEntry* fatEntry()
362 {
363 ASSERT(isFat());
364 return bitwise_cast<FatEntry*>(m_bits);
365 }
366
367 FatEntry* inflate()
368 {
369 if (LIKELY(isFat()))
370 return fatEntry();
371 return inflateSlow();
372 }
373
374 FatEntry* inflateSlow();
375
376 ALWAYS_INLINE intptr_t bits() const
377 {
378 if (isFat())
379 return fatEntry()->m_bits;
380 return m_bits;
381 }
382
383 ALWAYS_INLINE intptr_t& bits()
384 {
385 if (isFat())
386 return fatEntry()->m_bits;
387 return m_bits;
388 }
389
390 void freeFatEntry()
391 {
392 if (LIKELY(!isFat()))
393 return;
394 freeFatEntrySlow();
395 }
396
397 JS_EXPORT_PRIVATE void freeFatEntrySlow();
398
399 void pack(VarOffset offset, bool isWatchable, bool readOnly, bool dontEnum)
400 {
401 ASSERT(!isFat());
402 intptr_t& bitsRef = bits();
403 bitsRef =
404 (static_cast<intptr_t>(offset.rawOffset()) << FlagBits) | NotNullFlag | SlimFlag;
405 if (readOnly)
406 bitsRef |= ReadOnlyFlag;
407 if (dontEnum)
408 bitsRef |= DontEnumFlag;
409 switch (offset.kind()) {
410 case VarKind::Scope:
411 if (isWatchable)
412 bitsRef |= ScopeKindBits;
413 else
414 bitsRef |= UnwatchableScopeKindBits;
415 break;
416 case VarKind::Stack:
417 bitsRef |= StackKindBits;
418 break;
419 case VarKind::DirectArgument:
420 bitsRef |= DirectArgumentKindBits;
421 break;
422 default:
423 RELEASE_ASSERT_NOT_REACHED();
424 break;
425 }
426 }
427
428 static bool isValidVarOffset(VarOffset offset)
429 {
430 return ((static_cast<intptr_t>(offset.rawOffset()) << FlagBits) >> FlagBits) == static_cast<intptr_t>(offset.rawOffset());
431 }
432
433 intptr_t m_bits;
434};
435
436struct SymbolTableIndexHashTraits : HashTraits<SymbolTableEntry> {
437 static const bool needsDestruction = true;
438};
439
440class SymbolTable final : public JSCell {
441 friend class CachedSymbolTable;
442
443public:
444 typedef JSCell Base;
445 static const unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
446
447 typedef HashMap<RefPtr<UniquedStringImpl>, SymbolTableEntry, IdentifierRepHash, HashTraits<RefPtr<UniquedStringImpl>>, SymbolTableIndexHashTraits> Map;
448 typedef HashMap<RefPtr<UniquedStringImpl>, GlobalVariableID, IdentifierRepHash> UniqueIDMap;
449 typedef HashMap<RefPtr<UniquedStringImpl>, RefPtr<TypeSet>, IdentifierRepHash> UniqueTypeSetMap;
450 typedef HashMap<VarOffset, RefPtr<UniquedStringImpl>> OffsetToVariableMap;
451 typedef Vector<SymbolTableEntry*> LocalToEntryVec;
452
453 static SymbolTable* create(VM& vm)
454 {
455 SymbolTable* symbolTable = new (NotNull, allocateCell<SymbolTable>(vm.heap)) SymbolTable(vm);
456 symbolTable->finishCreation(vm);
457 return symbolTable;
458 }
459
460 static const bool needsDestruction = true;
461 static void destroy(JSCell*);
462
463 static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
464 {
465 return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
466 }
467
468 // You must hold the lock until after you're done with the iterator.
469 Map::iterator find(const ConcurrentJSLocker&, UniquedStringImpl* key)
470 {
471 return m_map.find(key);
472 }
473
474 Map::iterator find(const GCSafeConcurrentJSLocker&, UniquedStringImpl* key)
475 {
476 return m_map.find(key);
477 }
478
479 SymbolTableEntry get(const ConcurrentJSLocker&, UniquedStringImpl* key)
480 {
481 return m_map.get(key);
482 }
483
484 SymbolTableEntry get(UniquedStringImpl* key)
485 {
486 ConcurrentJSLocker locker(m_lock);
487 return get(locker, key);
488 }
489
490 SymbolTableEntry inlineGet(const ConcurrentJSLocker&, UniquedStringImpl* key)
491 {
492 return m_map.inlineGet(key);
493 }
494
495 SymbolTableEntry inlineGet(UniquedStringImpl* key)
496 {
497 ConcurrentJSLocker locker(m_lock);
498 return inlineGet(locker, key);
499 }
500
501 Map::iterator begin(const ConcurrentJSLocker&)
502 {
503 return m_map.begin();
504 }
505
506 Map::iterator end(const ConcurrentJSLocker&)
507 {
508 return m_map.end();
509 }
510
511 Map::iterator end(const GCSafeConcurrentJSLocker&)
512 {
513 return m_map.end();
514 }
515
516 size_t size(const ConcurrentJSLocker&) const
517 {
518 return m_map.size();
519 }
520
521 size_t size() const
522 {
523 ConcurrentJSLocker locker(m_lock);
524 return size(locker);
525 }
526
527 ScopeOffset maxScopeOffset() const
528 {
529 return m_maxScopeOffset;
530 }
531
532 void didUseScopeOffset(ScopeOffset offset)
533 {
534 if (!m_maxScopeOffset || m_maxScopeOffset < offset)
535 m_maxScopeOffset = offset;
536 }
537
538 void didUseVarOffset(VarOffset offset)
539 {
540 if (offset.isScope())
541 didUseScopeOffset(offset.scopeOffset());
542 }
543
544 unsigned scopeSize() const
545 {
546 ScopeOffset maxScopeOffset = this->maxScopeOffset();
547
548 // Do some calculation that relies on invalid scope offset plus one being zero.
549 unsigned fastResult = maxScopeOffset.offsetUnchecked() + 1;
550
551 // Assert that this works.
552 ASSERT(fastResult == (!maxScopeOffset ? 0 : maxScopeOffset.offset() + 1));
553
554 return fastResult;
555 }
556
557 ScopeOffset nextScopeOffset() const
558 {
559 return ScopeOffset(scopeSize());
560 }
561
562 ScopeOffset takeNextScopeOffset(const ConcurrentJSLocker&)
563 {
564 ScopeOffset result = nextScopeOffset();
565 m_maxScopeOffset = result;
566 return result;
567 }
568
569 ScopeOffset takeNextScopeOffset()
570 {
571 ConcurrentJSLocker locker(m_lock);
572 return takeNextScopeOffset(locker);
573 }
574
575 template<typename Entry>
576 void add(const ConcurrentJSLocker&, UniquedStringImpl* key, Entry&& entry)
577 {
578 RELEASE_ASSERT(!m_localToEntry);
579 didUseVarOffset(entry.varOffset());
580 Map::AddResult result = m_map.add(key, std::forward<Entry>(entry));
581 ASSERT_UNUSED(result, result.isNewEntry);
582 }
583
584 template<typename Entry>
585 void add(UniquedStringImpl* key, Entry&& entry)
586 {
587 ConcurrentJSLocker locker(m_lock);
588 add(locker, key, std::forward<Entry>(entry));
589 }
590
591 template<typename Entry>
592 void set(const ConcurrentJSLocker&, UniquedStringImpl* key, Entry&& entry)
593 {
594 RELEASE_ASSERT(!m_localToEntry);
595 didUseVarOffset(entry.varOffset());
596 m_map.set(key, std::forward<Entry>(entry));
597 }
598
599 template<typename Entry>
600 void set(UniquedStringImpl* key, Entry&& entry)
601 {
602 ConcurrentJSLocker locker(m_lock);
603 set(locker, key, std::forward<Entry>(entry));
604 }
605
606 bool contains(const ConcurrentJSLocker&, UniquedStringImpl* key)
607 {
608 return m_map.contains(key);
609 }
610
611 bool contains(UniquedStringImpl* key)
612 {
613 ConcurrentJSLocker locker(m_lock);
614 return contains(locker, key);
615 }
616
617 // The principle behind ScopedArgumentsTable modifications is that we will create one and
618 // leave it unlocked - thereby allowing in-place changes - until someone asks for a pointer to
619 // the table. Then, we will lock it. Then both our future changes and their future changes
620 // will first have to make a copy. This discipline means that usually when we create a
621 // ScopedArguments object, we don't have to make a copy of the ScopedArgumentsTable - instead
622 // we just take a reference to one that we already have.
623
624 uint32_t argumentsLength() const
625 {
626 if (!m_arguments)
627 return 0;
628 return m_arguments->length();
629 }
630
631 void setArgumentsLength(VM& vm, uint32_t length)
632 {
633 if (UNLIKELY(!m_arguments))
634 m_arguments.set(vm, this, ScopedArgumentsTable::create(vm, length));
635 else
636 m_arguments.set(vm, this, m_arguments->setLength(vm, length));
637 }
638
639 ScopeOffset argumentOffset(uint32_t i) const
640 {
641 ASSERT_WITH_SECURITY_IMPLICATION(m_arguments);
642 return m_arguments->get(i);
643 }
644
645 void setArgumentOffset(VM& vm, uint32_t i, ScopeOffset offset)
646 {
647 ASSERT_WITH_SECURITY_IMPLICATION(m_arguments);
648 m_arguments.set(vm, this, m_arguments->set(vm, i, offset));
649 }
650
651 ScopedArgumentsTable* arguments() const
652 {
653 if (!m_arguments)
654 return nullptr;
655 m_arguments->lock();
656 return m_arguments.get();
657 }
658
659 const LocalToEntryVec& localToEntry(const ConcurrentJSLocker&);
660 SymbolTableEntry* entryFor(const ConcurrentJSLocker&, ScopeOffset);
661
662 GlobalVariableID uniqueIDForVariable(const ConcurrentJSLocker&, UniquedStringImpl* key, VM&);
663 GlobalVariableID uniqueIDForOffset(const ConcurrentJSLocker&, VarOffset, VM&);
664 RefPtr<TypeSet> globalTypeSetForOffset(const ConcurrentJSLocker&, VarOffset, VM&);
665 RefPtr<TypeSet> globalTypeSetForVariable(const ConcurrentJSLocker&, UniquedStringImpl* key, VM&);
666
667 bool usesNonStrictEval() const { return m_usesNonStrictEval; }
668 void setUsesNonStrictEval(bool usesNonStrictEval) { m_usesNonStrictEval = usesNonStrictEval; }
669
670 bool isNestedLexicalScope() const { return m_nestedLexicalScope; }
671 void markIsNestedLexicalScope() { ASSERT(scopeType() == LexicalScope); m_nestedLexicalScope = true; }
672
673 enum ScopeType {
674 VarScope,
675 GlobalLexicalScope,
676 LexicalScope,
677 CatchScope,
678 FunctionNameScope
679 };
680 void setScopeType(ScopeType type) { m_scopeType = type; }
681 ScopeType scopeType() const { return static_cast<ScopeType>(m_scopeType); }
682
683 SymbolTable* cloneScopePart(VM&);
684
685 void prepareForTypeProfiling(const ConcurrentJSLocker&);
686
687 CodeBlock* rareDataCodeBlock();
688 void setRareDataCodeBlock(CodeBlock*);
689
690 InferredValue* singletonScope() { return m_singletonScope.get(); }
691
692 static void visitChildren(JSCell*, SlotVisitor&);
693
694 DECLARE_EXPORT_INFO;
695
696private:
697 JS_EXPORT_PRIVATE SymbolTable(VM&);
698 ~SymbolTable();
699
700 JS_EXPORT_PRIVATE void finishCreation(VM&);
701
702 Map m_map;
703 ScopeOffset m_maxScopeOffset;
704public:
705 mutable ConcurrentJSLock m_lock;
706private:
707 unsigned m_usesNonStrictEval : 1;
708 unsigned m_nestedLexicalScope : 1; // Non-function LexicalScope.
709 unsigned m_scopeType : 3; // ScopeType
710
711 struct SymbolTableRareData {
712 UniqueIDMap m_uniqueIDMap;
713 OffsetToVariableMap m_offsetToVariableMap;
714 UniqueTypeSetMap m_uniqueTypeSetMap;
715 WriteBarrier<CodeBlock> m_codeBlock;
716 };
717 std::unique_ptr<SymbolTableRareData> m_rareData;
718
719 WriteBarrier<ScopedArgumentsTable> m_arguments;
720 WriteBarrier<InferredValue> m_singletonScope;
721
722 std::unique_ptr<LocalToEntryVec> m_localToEntry;
723};
724
725} // namespace JSC
726