xref: /freebsd/contrib/llvm-project/compiler-rt/lib/tsan/rtl/tsan_rtl.h (revision c1d255d3ffdbe447de3ab875bf4e7d7accc5bfc5)
1 //===-- tsan_rtl.h ----------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file is a part of ThreadSanitizer (TSan), a race detector.
10 //
11 // Main internal TSan header file.
12 //
13 // Ground rules:
14 //   - C++ run-time should not be used (static CTORs, RTTI, exceptions, static
15 //     function-scope locals)
16 //   - All functions/classes/etc reside in namespace __tsan, except for those
17 //     declared in tsan_interface.h.
18 //   - Platform-specific files should be used instead of ifdefs (*).
19 //   - No system headers included in header files (*).
20 //   - Platform specific headres included only into platform-specific files (*).
21 //
22 //  (*) Except when inlining is critical for performance.
23 //===----------------------------------------------------------------------===//
24 
25 #ifndef TSAN_RTL_H
26 #define TSAN_RTL_H
27 
28 #include "sanitizer_common/sanitizer_allocator.h"
29 #include "sanitizer_common/sanitizer_allocator_internal.h"
30 #include "sanitizer_common/sanitizer_asm.h"
31 #include "sanitizer_common/sanitizer_common.h"
32 #include "sanitizer_common/sanitizer_deadlock_detector_interface.h"
33 #include "sanitizer_common/sanitizer_libignore.h"
34 #include "sanitizer_common/sanitizer_suppressions.h"
35 #include "sanitizer_common/sanitizer_thread_registry.h"
36 #include "sanitizer_common/sanitizer_vector.h"
37 #include "tsan_clock.h"
38 #include "tsan_defs.h"
39 #include "tsan_flags.h"
40 #include "tsan_mman.h"
41 #include "tsan_sync.h"
42 #include "tsan_trace.h"
43 #include "tsan_report.h"
44 #include "tsan_platform.h"
45 #include "tsan_mutexset.h"
46 #include "tsan_ignoreset.h"
47 #include "tsan_stack_trace.h"
48 
49 #if SANITIZER_WORDSIZE != 64
50 # error "ThreadSanitizer is supported only on 64-bit platforms"
51 #endif
52 
53 namespace __tsan {
54 
55 #if !SANITIZER_GO
56 struct MapUnmapCallback;
57 #if defined(__mips64) || defined(__aarch64__) || defined(__powerpc__)
58 
59 struct AP32 {
60   static const uptr kSpaceBeg = 0;
61   static const u64 kSpaceSize = SANITIZER_MMAP_RANGE_SIZE;
62   static const uptr kMetadataSize = 0;
63   typedef __sanitizer::CompactSizeClassMap SizeClassMap;
64   static const uptr kRegionSizeLog = 20;
65   using AddressSpaceView = LocalAddressSpaceView;
66   typedef __tsan::MapUnmapCallback MapUnmapCallback;
67   static const uptr kFlags = 0;
68 };
69 typedef SizeClassAllocator32<AP32> PrimaryAllocator;
70 #else
71 struct AP64 {  // Allocator64 parameters. Deliberately using a short name.
72   static const uptr kSpaceBeg = Mapping::kHeapMemBeg;
73   static const uptr kSpaceSize = Mapping::kHeapMemEnd - Mapping::kHeapMemBeg;
74   static const uptr kMetadataSize = 0;
75   typedef DefaultSizeClassMap SizeClassMap;
76   typedef __tsan::MapUnmapCallback MapUnmapCallback;
77   static const uptr kFlags = 0;
78   using AddressSpaceView = LocalAddressSpaceView;
79 };
80 typedef SizeClassAllocator64<AP64> PrimaryAllocator;
81 #endif
82 typedef CombinedAllocator<PrimaryAllocator> Allocator;
83 typedef Allocator::AllocatorCache AllocatorCache;
84 Allocator *allocator();
85 #endif
86 
87 void TsanCheckFailed(const char *file, int line, const char *cond,
88                      u64 v1, u64 v2);
89 
90 const u64 kShadowRodata = (u64)-1;  // .rodata shadow marker
91 
92 // FastState (from most significant bit):
93 //   ignore          : 1
94 //   tid             : kTidBits
95 //   unused          : -
96 //   history_size    : 3
97 //   epoch           : kClkBits
98 class FastState {
99  public:
100   FastState(u64 tid, u64 epoch) {
101     x_ = tid << kTidShift;
102     x_ |= epoch;
103     DCHECK_EQ(tid, this->tid());
104     DCHECK_EQ(epoch, this->epoch());
105     DCHECK_EQ(GetIgnoreBit(), false);
106   }
107 
108   explicit FastState(u64 x)
109       : x_(x) {
110   }
111 
112   u64 raw() const {
113     return x_;
114   }
115 
116   u64 tid() const {
117     u64 res = (x_ & ~kIgnoreBit) >> kTidShift;
118     return res;
119   }
120 
121   u64 TidWithIgnore() const {
122     u64 res = x_ >> kTidShift;
123     return res;
124   }
125 
126   u64 epoch() const {
127     u64 res = x_ & ((1ull << kClkBits) - 1);
128     return res;
129   }
130 
131   void IncrementEpoch() {
132     u64 old_epoch = epoch();
133     x_ += 1;
134     DCHECK_EQ(old_epoch + 1, epoch());
135     (void)old_epoch;
136   }
137 
138   void SetIgnoreBit() { x_ |= kIgnoreBit; }
139   void ClearIgnoreBit() { x_ &= ~kIgnoreBit; }
140   bool GetIgnoreBit() const { return (s64)x_ < 0; }
141 
142   void SetHistorySize(int hs) {
143     CHECK_GE(hs, 0);
144     CHECK_LE(hs, 7);
145     x_ = (x_ & ~(kHistoryMask << kHistoryShift)) | (u64(hs) << kHistoryShift);
146   }
147 
148   ALWAYS_INLINE
149   int GetHistorySize() const {
150     return (int)((x_ >> kHistoryShift) & kHistoryMask);
151   }
152 
153   void ClearHistorySize() {
154     SetHistorySize(0);
155   }
156 
157   ALWAYS_INLINE
158   u64 GetTracePos() const {
159     const int hs = GetHistorySize();
160     // When hs == 0, the trace consists of 2 parts.
161     const u64 mask = (1ull << (kTracePartSizeBits + hs + 1)) - 1;
162     return epoch() & mask;
163   }
164 
165  private:
166   friend class Shadow;
167   static const int kTidShift = 64 - kTidBits - 1;
168   static const u64 kIgnoreBit = 1ull << 63;
169   static const u64 kFreedBit = 1ull << 63;
170   static const u64 kHistoryShift = kClkBits;
171   static const u64 kHistoryMask = 7;
172   u64 x_;
173 };
174 
175 // Shadow (from most significant bit):
176 //   freed           : 1
177 //   tid             : kTidBits
178 //   is_atomic       : 1
179 //   is_read         : 1
180 //   size_log        : 2
181 //   addr0           : 3
182 //   epoch           : kClkBits
183 class Shadow : public FastState {
184  public:
185   explicit Shadow(u64 x)
186       : FastState(x) {
187   }
188 
189   explicit Shadow(const FastState &s)
190       : FastState(s.x_) {
191     ClearHistorySize();
192   }
193 
194   void SetAddr0AndSizeLog(u64 addr0, unsigned kAccessSizeLog) {
195     DCHECK_EQ((x_ >> kClkBits) & 31, 0);
196     DCHECK_LE(addr0, 7);
197     DCHECK_LE(kAccessSizeLog, 3);
198     x_ |= ((kAccessSizeLog << 3) | addr0) << kClkBits;
199     DCHECK_EQ(kAccessSizeLog, size_log());
200     DCHECK_EQ(addr0, this->addr0());
201   }
202 
203   void SetWrite(unsigned kAccessIsWrite) {
204     DCHECK_EQ(x_ & kReadBit, 0);
205     if (!kAccessIsWrite)
206       x_ |= kReadBit;
207     DCHECK_EQ(kAccessIsWrite, IsWrite());
208   }
209 
210   void SetAtomic(bool kIsAtomic) {
211     DCHECK(!IsAtomic());
212     if (kIsAtomic)
213       x_ |= kAtomicBit;
214     DCHECK_EQ(IsAtomic(), kIsAtomic);
215   }
216 
217   bool IsAtomic() const {
218     return x_ & kAtomicBit;
219   }
220 
221   bool IsZero() const {
222     return x_ == 0;
223   }
224 
225   static inline bool TidsAreEqual(const Shadow s1, const Shadow s2) {
226     u64 shifted_xor = (s1.x_ ^ s2.x_) >> kTidShift;
227     DCHECK_EQ(shifted_xor == 0, s1.TidWithIgnore() == s2.TidWithIgnore());
228     return shifted_xor == 0;
229   }
230 
231   static ALWAYS_INLINE
232   bool Addr0AndSizeAreEqual(const Shadow s1, const Shadow s2) {
233     u64 masked_xor = ((s1.x_ ^ s2.x_) >> kClkBits) & 31;
234     return masked_xor == 0;
235   }
236 
237   static ALWAYS_INLINE bool TwoRangesIntersect(Shadow s1, Shadow s2,
238       unsigned kS2AccessSize) {
239     bool res = false;
240     u64 diff = s1.addr0() - s2.addr0();
241     if ((s64)diff < 0) {  // s1.addr0 < s2.addr0
242       // if (s1.addr0() + size1) > s2.addr0()) return true;
243       if (s1.size() > -diff)
244         res = true;
245     } else {
246       // if (s2.addr0() + kS2AccessSize > s1.addr0()) return true;
247       if (kS2AccessSize > diff)
248         res = true;
249     }
250     DCHECK_EQ(res, TwoRangesIntersectSlow(s1, s2));
251     DCHECK_EQ(res, TwoRangesIntersectSlow(s2, s1));
252     return res;
253   }
254 
255   u64 ALWAYS_INLINE addr0() const { return (x_ >> kClkBits) & 7; }
256   u64 ALWAYS_INLINE size() const { return 1ull << size_log(); }
257   bool ALWAYS_INLINE IsWrite() const { return !IsRead(); }
258   bool ALWAYS_INLINE IsRead() const { return x_ & kReadBit; }
259 
260   // The idea behind the freed bit is as follows.
261   // When the memory is freed (or otherwise unaccessible) we write to the shadow
262   // values with tid/epoch related to the free and the freed bit set.
263   // During memory accesses processing the freed bit is considered
264   // as msb of tid. So any access races with shadow with freed bit set
265   // (it is as if write from a thread with which we never synchronized before).
266   // This allows us to detect accesses to freed memory w/o additional
267   // overheads in memory access processing and at the same time restore
268   // tid/epoch of free.
269   void MarkAsFreed() {
270      x_ |= kFreedBit;
271   }
272 
273   bool IsFreed() const {
274     return x_ & kFreedBit;
275   }
276 
277   bool GetFreedAndReset() {
278     bool res = x_ & kFreedBit;
279     x_ &= ~kFreedBit;
280     return res;
281   }
282 
283   bool ALWAYS_INLINE IsBothReadsOrAtomic(bool kIsWrite, bool kIsAtomic) const {
284     bool v = x_ & ((u64(kIsWrite ^ 1) << kReadShift)
285         | (u64(kIsAtomic) << kAtomicShift));
286     DCHECK_EQ(v, (!IsWrite() && !kIsWrite) || (IsAtomic() && kIsAtomic));
287     return v;
288   }
289 
290   bool ALWAYS_INLINE IsRWNotWeaker(bool kIsWrite, bool kIsAtomic) const {
291     bool v = ((x_ >> kReadShift) & 3)
292         <= u64((kIsWrite ^ 1) | (kIsAtomic << 1));
293     DCHECK_EQ(v, (IsAtomic() < kIsAtomic) ||
294         (IsAtomic() == kIsAtomic && !IsWrite() <= !kIsWrite));
295     return v;
296   }
297 
298   bool ALWAYS_INLINE IsRWWeakerOrEqual(bool kIsWrite, bool kIsAtomic) const {
299     bool v = ((x_ >> kReadShift) & 3)
300         >= u64((kIsWrite ^ 1) | (kIsAtomic << 1));
301     DCHECK_EQ(v, (IsAtomic() > kIsAtomic) ||
302         (IsAtomic() == kIsAtomic && !IsWrite() >= !kIsWrite));
303     return v;
304   }
305 
306  private:
307   static const u64 kReadShift   = 5 + kClkBits;
308   static const u64 kReadBit     = 1ull << kReadShift;
309   static const u64 kAtomicShift = 6 + kClkBits;
310   static const u64 kAtomicBit   = 1ull << kAtomicShift;
311 
312   u64 size_log() const { return (x_ >> (3 + kClkBits)) & 3; }
313 
314   static bool TwoRangesIntersectSlow(const Shadow s1, const Shadow s2) {
315     if (s1.addr0() == s2.addr0()) return true;
316     if (s1.addr0() < s2.addr0() && s1.addr0() + s1.size() > s2.addr0())
317       return true;
318     if (s2.addr0() < s1.addr0() && s2.addr0() + s2.size() > s1.addr0())
319       return true;
320     return false;
321   }
322 };
323 
324 struct ThreadSignalContext;
325 
326 struct JmpBuf {
327   uptr sp;
328   int int_signal_send;
329   bool in_blocking_func;
330   uptr in_signal_handler;
331   uptr *shadow_stack_pos;
332 };
333 
334 // A Processor represents a physical thread, or a P for Go.
335 // It is used to store internal resources like allocate cache, and does not
336 // participate in race-detection logic (invisible to end user).
337 // In C++ it is tied to an OS thread just like ThreadState, however ideally
338 // it should be tied to a CPU (this way we will have fewer allocator caches).
339 // In Go it is tied to a P, so there are significantly fewer Processor's than
340 // ThreadState's (which are tied to Gs).
341 // A ThreadState must be wired with a Processor to handle events.
342 struct Processor {
343   ThreadState *thr; // currently wired thread, or nullptr
344 #if !SANITIZER_GO
345   AllocatorCache alloc_cache;
346   InternalAllocatorCache internal_alloc_cache;
347 #endif
348   DenseSlabAllocCache block_cache;
349   DenseSlabAllocCache sync_cache;
350   DenseSlabAllocCache clock_cache;
351   DDPhysicalThread *dd_pt;
352 };
353 
354 #if !SANITIZER_GO
355 // ScopedGlobalProcessor temporary setups a global processor for the current
356 // thread, if it does not have one. Intended for interceptors that can run
357 // at the very thread end, when we already destroyed the thread processor.
358 struct ScopedGlobalProcessor {
359   ScopedGlobalProcessor();
360   ~ScopedGlobalProcessor();
361 };
362 #endif
363 
364 // This struct is stored in TLS.
365 struct ThreadState {
366   FastState fast_state;
367   // Synch epoch represents the threads's epoch before the last synchronization
368   // action. It allows to reduce number of shadow state updates.
369   // For example, fast_synch_epoch=100, last write to addr X was at epoch=150,
370   // if we are processing write to X from the same thread at epoch=200,
371   // we do nothing, because both writes happen in the same 'synch epoch'.
372   // That is, if another memory access does not race with the former write,
373   // it does not race with the latter as well.
374   // QUESTION: can we can squeeze this into ThreadState::Fast?
375   // E.g. ThreadState::Fast is a 44-bit, 32 are taken by synch_epoch and 12 are
376   // taken by epoch between synchs.
377   // This way we can save one load from tls.
378   u64 fast_synch_epoch;
379   // Technically `current` should be a separate THREADLOCAL variable;
380   // but it is placed here in order to share cache line with previous fields.
381   ThreadState* current;
382   // This is a slow path flag. On fast path, fast_state.GetIgnoreBit() is read.
383   // We do not distinguish beteween ignoring reads and writes
384   // for better performance.
385   int ignore_reads_and_writes;
386   int ignore_sync;
387   int suppress_reports;
388   // Go does not support ignores.
389 #if !SANITIZER_GO
390   IgnoreSet mop_ignore_set;
391   IgnoreSet sync_ignore_set;
392 #endif
393   // C/C++ uses fixed size shadow stack embed into Trace.
394   // Go uses malloc-allocated shadow stack with dynamic size.
395   uptr *shadow_stack;
396   uptr *shadow_stack_end;
397   uptr *shadow_stack_pos;
398   u64 *racy_shadow_addr;
399   u64 racy_state[2];
400   MutexSet mset;
401   ThreadClock clock;
402 #if !SANITIZER_GO
403   Vector<JmpBuf> jmp_bufs;
404   int ignore_interceptors;
405 #endif
406 #if TSAN_COLLECT_STATS
407   u64 stat[StatCnt];
408 #endif
409   const int tid;
410   const int unique_id;
411   bool in_symbolizer;
412   bool in_ignored_lib;
413   bool is_inited;
414   bool is_dead;
415   bool is_freeing;
416   bool is_vptr_access;
417   const uptr stk_addr;
418   const uptr stk_size;
419   const uptr tls_addr;
420   const uptr tls_size;
421   ThreadContext *tctx;
422 
423 #if SANITIZER_DEBUG && !SANITIZER_GO
424   InternalDeadlockDetector internal_deadlock_detector;
425 #endif
426   DDLogicalThread *dd_lt;
427 
428   // Current wired Processor, or nullptr. Required to handle any events.
429   Processor *proc1;
430 #if !SANITIZER_GO
431   Processor *proc() { return proc1; }
432 #else
433   Processor *proc();
434 #endif
435 
436   atomic_uintptr_t in_signal_handler;
437   ThreadSignalContext *signal_ctx;
438 
439 #if !SANITIZER_GO
440   u32 last_sleep_stack_id;
441   ThreadClock last_sleep_clock;
442 #endif
443 
444   // Set in regions of runtime that must be signal-safe and fork-safe.
445   // If set, malloc must not be called.
446   int nomalloc;
447 
448   const ReportDesc *current_report;
449 
450   explicit ThreadState(Context *ctx, int tid, int unique_id, u64 epoch,
451                        unsigned reuse_count,
452                        uptr stk_addr, uptr stk_size,
453                        uptr tls_addr, uptr tls_size);
454 };
455 
456 #if !SANITIZER_GO
457 #if SANITIZER_MAC || SANITIZER_ANDROID
458 ThreadState *cur_thread();
459 void set_cur_thread(ThreadState *thr);
460 void cur_thread_finalize();
461 inline void cur_thread_init() { }
462 #else
463 __attribute__((tls_model("initial-exec")))
464 extern THREADLOCAL char cur_thread_placeholder[];
465 inline ThreadState *cur_thread() {
466   return reinterpret_cast<ThreadState *>(cur_thread_placeholder)->current;
467 }
468 inline void cur_thread_init() {
469   ThreadState *thr = reinterpret_cast<ThreadState *>(cur_thread_placeholder);
470   if (UNLIKELY(!thr->current))
471     thr->current = thr;
472 }
473 inline void set_cur_thread(ThreadState *thr) {
474   reinterpret_cast<ThreadState *>(cur_thread_placeholder)->current = thr;
475 }
476 inline void cur_thread_finalize() { }
477 #endif  // SANITIZER_MAC || SANITIZER_ANDROID
478 #endif  // SANITIZER_GO
479 
480 class ThreadContext final : public ThreadContextBase {
481  public:
482   explicit ThreadContext(int tid);
483   ~ThreadContext();
484   ThreadState *thr;
485   u32 creation_stack_id;
486   SyncClock sync;
487   // Epoch at which the thread had started.
488   // If we see an event from the thread stamped by an older epoch,
489   // the event is from a dead thread that shared tid with this thread.
490   u64 epoch0;
491   u64 epoch1;
492 
493   // Override superclass callbacks.
494   void OnDead() override;
495   void OnJoined(void *arg) override;
496   void OnFinished() override;
497   void OnStarted(void *arg) override;
498   void OnCreated(void *arg) override;
499   void OnReset() override;
500   void OnDetached(void *arg) override;
501 };
502 
503 struct RacyStacks {
504   MD5Hash hash[2];
505   bool operator==(const RacyStacks &other) const {
506     if (hash[0] == other.hash[0] && hash[1] == other.hash[1])
507       return true;
508     if (hash[0] == other.hash[1] && hash[1] == other.hash[0])
509       return true;
510     return false;
511   }
512 };
513 
514 struct RacyAddress {
515   uptr addr_min;
516   uptr addr_max;
517 };
518 
519 struct FiredSuppression {
520   ReportType type;
521   uptr pc_or_addr;
522   Suppression *supp;
523 };
524 
525 struct Context {
526   Context();
527 
528   bool initialized;
529 #if !SANITIZER_GO
530   bool after_multithreaded_fork;
531 #endif
532 
533   MetaMap metamap;
534 
535   Mutex report_mtx;
536   int nreported;
537   int nmissed_expected;
538   atomic_uint64_t last_symbolize_time_ns;
539 
540   void *background_thread;
541   atomic_uint32_t stop_background_thread;
542 
543   ThreadRegistry *thread_registry;
544 
545   Mutex racy_mtx;
546   Vector<RacyStacks> racy_stacks;
547   Vector<RacyAddress> racy_addresses;
548   // Number of fired suppressions may be large enough.
549   Mutex fired_suppressions_mtx;
550   InternalMmapVector<FiredSuppression> fired_suppressions;
551   DDetector *dd;
552 
553   ClockAlloc clock_alloc;
554 
555   Flags flags;
556 
557   u64 stat[StatCnt];
558   u64 int_alloc_cnt[MBlockTypeCount];
559   u64 int_alloc_siz[MBlockTypeCount];
560 };
561 
562 extern Context *ctx;  // The one and the only global runtime context.
563 
564 ALWAYS_INLINE Flags *flags() {
565   return &ctx->flags;
566 }
567 
568 struct ScopedIgnoreInterceptors {
569   ScopedIgnoreInterceptors() {
570 #if !SANITIZER_GO
571     cur_thread()->ignore_interceptors++;
572 #endif
573   }
574 
575   ~ScopedIgnoreInterceptors() {
576 #if !SANITIZER_GO
577     cur_thread()->ignore_interceptors--;
578 #endif
579   }
580 };
581 
582 const char *GetObjectTypeFromTag(uptr tag);
583 const char *GetReportHeaderFromTag(uptr tag);
584 uptr TagFromShadowStackFrame(uptr pc);
585 
586 class ScopedReportBase {
587  public:
588   void AddMemoryAccess(uptr addr, uptr external_tag, Shadow s, StackTrace stack,
589                        const MutexSet *mset);
590   void AddStack(StackTrace stack, bool suppressable = false);
591   void AddThread(const ThreadContext *tctx, bool suppressable = false);
592   void AddThread(int unique_tid, bool suppressable = false);
593   void AddUniqueTid(int unique_tid);
594   void AddMutex(const SyncVar *s);
595   u64 AddMutex(u64 id);
596   void AddLocation(uptr addr, uptr size);
597   void AddSleep(u32 stack_id);
598   void SetCount(int count);
599 
600   const ReportDesc *GetReport() const;
601 
602  protected:
603   ScopedReportBase(ReportType typ, uptr tag);
604   ~ScopedReportBase();
605 
606  private:
607   ReportDesc *rep_;
608   // Symbolizer makes lots of intercepted calls. If we try to process them,
609   // at best it will cause deadlocks on internal mutexes.
610   ScopedIgnoreInterceptors ignore_interceptors_;
611 
612   void AddDeadMutex(u64 id);
613 
614   ScopedReportBase(const ScopedReportBase &) = delete;
615   void operator=(const ScopedReportBase &) = delete;
616 };
617 
618 class ScopedReport : public ScopedReportBase {
619  public:
620   explicit ScopedReport(ReportType typ, uptr tag = kExternalTagNone);
621   ~ScopedReport();
622 
623  private:
624   ScopedErrorReportLock lock_;
625 };
626 
627 ThreadContext *IsThreadStackOrTls(uptr addr, bool *is_stack);
628 void RestoreStack(int tid, const u64 epoch, VarSizeStackTrace *stk,
629                   MutexSet *mset, uptr *tag = nullptr);
630 
631 // The stack could look like:
632 //   <start> | <main> | <foo> | tag | <bar>
633 // This will extract the tag and keep:
634 //   <start> | <main> | <foo> | <bar>
635 template<typename StackTraceTy>
636 void ExtractTagFromStack(StackTraceTy *stack, uptr *tag = nullptr) {
637   if (stack->size < 2) return;
638   uptr possible_tag_pc = stack->trace[stack->size - 2];
639   uptr possible_tag = TagFromShadowStackFrame(possible_tag_pc);
640   if (possible_tag == kExternalTagNone) return;
641   stack->trace_buffer[stack->size - 2] = stack->trace_buffer[stack->size - 1];
642   stack->size -= 1;
643   if (tag) *tag = possible_tag;
644 }
645 
646 template<typename StackTraceTy>
647 void ObtainCurrentStack(ThreadState *thr, uptr toppc, StackTraceTy *stack,
648                         uptr *tag = nullptr) {
649   uptr size = thr->shadow_stack_pos - thr->shadow_stack;
650   uptr start = 0;
651   if (size + !!toppc > kStackTraceMax) {
652     start = size + !!toppc - kStackTraceMax;
653     size = kStackTraceMax - !!toppc;
654   }
655   stack->Init(&thr->shadow_stack[start], size, toppc);
656   ExtractTagFromStack(stack, tag);
657 }
658 
659 #define GET_STACK_TRACE_FATAL(thr, pc) \
660   VarSizeStackTrace stack; \
661   ObtainCurrentStack(thr, pc, &stack); \
662   stack.ReverseOrder();
663 
664 #if TSAN_COLLECT_STATS
665 void StatAggregate(u64 *dst, u64 *src);
666 void StatOutput(u64 *stat);
667 #endif
668 
669 void ALWAYS_INLINE StatInc(ThreadState *thr, StatType typ, u64 n = 1) {
670 #if TSAN_COLLECT_STATS
671   thr->stat[typ] += n;
672 #endif
673 }
674 void ALWAYS_INLINE StatSet(ThreadState *thr, StatType typ, u64 n) {
675 #if TSAN_COLLECT_STATS
676   thr->stat[typ] = n;
677 #endif
678 }
679 
680 void MapShadow(uptr addr, uptr size);
681 void MapThreadTrace(uptr addr, uptr size, const char *name);
682 void DontNeedShadowFor(uptr addr, uptr size);
683 void UnmapShadow(ThreadState *thr, uptr addr, uptr size);
684 void InitializeShadowMemory();
685 void InitializeInterceptors();
686 void InitializeLibIgnore();
687 void InitializeDynamicAnnotations();
688 
689 void ForkBefore(ThreadState *thr, uptr pc);
690 void ForkParentAfter(ThreadState *thr, uptr pc);
691 void ForkChildAfter(ThreadState *thr, uptr pc);
692 
693 void ReportRace(ThreadState *thr);
694 bool OutputReport(ThreadState *thr, const ScopedReport &srep);
695 bool IsFiredSuppression(Context *ctx, ReportType type, StackTrace trace);
696 bool IsExpectedReport(uptr addr, uptr size);
697 void PrintMatchedBenignRaces();
698 
699 #if defined(TSAN_DEBUG_OUTPUT) && TSAN_DEBUG_OUTPUT >= 1
700 # define DPrintf Printf
701 #else
702 # define DPrintf(...)
703 #endif
704 
705 #if defined(TSAN_DEBUG_OUTPUT) && TSAN_DEBUG_OUTPUT >= 2
706 # define DPrintf2 Printf
707 #else
708 # define DPrintf2(...)
709 #endif
710 
711 u32 CurrentStackId(ThreadState *thr, uptr pc);
712 ReportStack *SymbolizeStackId(u32 stack_id);
713 void PrintCurrentStack(ThreadState *thr, uptr pc);
714 void PrintCurrentStackSlow(uptr pc);  // uses libunwind
715 
716 void Initialize(ThreadState *thr);
717 void MaybeSpawnBackgroundThread();
718 int Finalize(ThreadState *thr);
719 
720 void OnUserAlloc(ThreadState *thr, uptr pc, uptr p, uptr sz, bool write);
721 void OnUserFree(ThreadState *thr, uptr pc, uptr p, bool write);
722 
723 void MemoryAccess(ThreadState *thr, uptr pc, uptr addr,
724     int kAccessSizeLog, bool kAccessIsWrite, bool kIsAtomic);
725 void MemoryAccessImpl(ThreadState *thr, uptr addr,
726     int kAccessSizeLog, bool kAccessIsWrite, bool kIsAtomic,
727     u64 *shadow_mem, Shadow cur);
728 void MemoryAccessRange(ThreadState *thr, uptr pc, uptr addr,
729     uptr size, bool is_write);
730 void MemoryAccessRangeStep(ThreadState *thr, uptr pc, uptr addr,
731     uptr size, uptr step, bool is_write);
732 void UnalignedMemoryAccess(ThreadState *thr, uptr pc, uptr addr,
733     int size, bool kAccessIsWrite, bool kIsAtomic);
734 
735 const int kSizeLog1 = 0;
736 const int kSizeLog2 = 1;
737 const int kSizeLog4 = 2;
738 const int kSizeLog8 = 3;
739 
740 void ALWAYS_INLINE MemoryRead(ThreadState *thr, uptr pc,
741                                      uptr addr, int kAccessSizeLog) {
742   MemoryAccess(thr, pc, addr, kAccessSizeLog, false, false);
743 }
744 
745 void ALWAYS_INLINE MemoryWrite(ThreadState *thr, uptr pc,
746                                       uptr addr, int kAccessSizeLog) {
747   MemoryAccess(thr, pc, addr, kAccessSizeLog, true, false);
748 }
749 
750 void ALWAYS_INLINE MemoryReadAtomic(ThreadState *thr, uptr pc,
751                                            uptr addr, int kAccessSizeLog) {
752   MemoryAccess(thr, pc, addr, kAccessSizeLog, false, true);
753 }
754 
755 void ALWAYS_INLINE MemoryWriteAtomic(ThreadState *thr, uptr pc,
756                                             uptr addr, int kAccessSizeLog) {
757   MemoryAccess(thr, pc, addr, kAccessSizeLog, true, true);
758 }
759 
760 void MemoryResetRange(ThreadState *thr, uptr pc, uptr addr, uptr size);
761 void MemoryRangeFreed(ThreadState *thr, uptr pc, uptr addr, uptr size);
762 void MemoryRangeImitateWrite(ThreadState *thr, uptr pc, uptr addr, uptr size);
763 void MemoryRangeImitateWriteOrResetRange(ThreadState *thr, uptr pc, uptr addr,
764                                          uptr size);
765 
766 void ThreadIgnoreBegin(ThreadState *thr, uptr pc, bool save_stack = true);
767 void ThreadIgnoreEnd(ThreadState *thr, uptr pc);
768 void ThreadIgnoreSyncBegin(ThreadState *thr, uptr pc, bool save_stack = true);
769 void ThreadIgnoreSyncEnd(ThreadState *thr, uptr pc);
770 
771 void FuncEntry(ThreadState *thr, uptr pc);
772 void FuncExit(ThreadState *thr);
773 
774 int ThreadCreate(ThreadState *thr, uptr pc, uptr uid, bool detached);
775 void ThreadStart(ThreadState *thr, int tid, tid_t os_id,
776                  ThreadType thread_type);
777 void ThreadFinish(ThreadState *thr);
778 int ThreadConsumeTid(ThreadState *thr, uptr pc, uptr uid);
779 void ThreadJoin(ThreadState *thr, uptr pc, int tid);
780 void ThreadDetach(ThreadState *thr, uptr pc, int tid);
781 void ThreadFinalize(ThreadState *thr);
782 void ThreadSetName(ThreadState *thr, const char *name);
783 int ThreadCount(ThreadState *thr);
784 void ProcessPendingSignals(ThreadState *thr);
785 void ThreadNotJoined(ThreadState *thr, uptr pc, int tid, uptr uid);
786 
787 Processor *ProcCreate();
788 void ProcDestroy(Processor *proc);
789 void ProcWire(Processor *proc, ThreadState *thr);
790 void ProcUnwire(Processor *proc, ThreadState *thr);
791 
792 // Note: the parameter is called flagz, because flags is already taken
793 // by the global function that returns flags.
794 void MutexCreate(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
795 void MutexDestroy(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
796 void MutexPreLock(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
797 void MutexPostLock(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0,
798     int rec = 1);
799 int  MutexUnlock(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
800 void MutexPreReadLock(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
801 void MutexPostReadLock(ThreadState *thr, uptr pc, uptr addr, u32 flagz = 0);
802 void MutexReadUnlock(ThreadState *thr, uptr pc, uptr addr);
803 void MutexReadOrWriteUnlock(ThreadState *thr, uptr pc, uptr addr);
804 void MutexRepair(ThreadState *thr, uptr pc, uptr addr);  // call on EOWNERDEAD
805 void MutexInvalidAccess(ThreadState *thr, uptr pc, uptr addr);
806 
807 void Acquire(ThreadState *thr, uptr pc, uptr addr);
808 // AcquireGlobal synchronizes the current thread with all other threads.
809 // In terms of happens-before relation, it draws a HB edge from all threads
810 // (where they happen to execute right now) to the current thread. We use it to
811 // handle Go finalizers. Namely, finalizer goroutine executes AcquireGlobal
812 // right before executing finalizers. This provides a coarse, but simple
813 // approximation of the actual required synchronization.
814 void AcquireGlobal(ThreadState *thr, uptr pc);
815 void Release(ThreadState *thr, uptr pc, uptr addr);
816 void ReleaseStoreAcquire(ThreadState *thr, uptr pc, uptr addr);
817 void ReleaseStore(ThreadState *thr, uptr pc, uptr addr);
818 void AfterSleep(ThreadState *thr, uptr pc);
819 void AcquireImpl(ThreadState *thr, uptr pc, SyncClock *c);
820 void ReleaseImpl(ThreadState *thr, uptr pc, SyncClock *c);
821 void ReleaseStoreAcquireImpl(ThreadState *thr, uptr pc, SyncClock *c);
822 void ReleaseStoreImpl(ThreadState *thr, uptr pc, SyncClock *c);
823 void AcquireReleaseImpl(ThreadState *thr, uptr pc, SyncClock *c);
824 
825 // The hacky call uses custom calling convention and an assembly thunk.
826 // It is considerably faster that a normal call for the caller
827 // if it is not executed (it is intended for slow paths from hot functions).
828 // The trick is that the call preserves all registers and the compiler
829 // does not treat it as a call.
830 // If it does not work for you, use normal call.
831 #if !SANITIZER_DEBUG && defined(__x86_64__) && !SANITIZER_MAC
832 // The caller may not create the stack frame for itself at all,
833 // so we create a reserve stack frame for it (1024b must be enough).
834 #define HACKY_CALL(f) \
835   __asm__ __volatile__("sub $1024, %%rsp;" \
836                        CFI_INL_ADJUST_CFA_OFFSET(1024) \
837                        ".hidden " #f "_thunk;" \
838                        "call " #f "_thunk;" \
839                        "add $1024, %%rsp;" \
840                        CFI_INL_ADJUST_CFA_OFFSET(-1024) \
841                        ::: "memory", "cc");
842 #else
843 #define HACKY_CALL(f) f()
844 #endif
845 
846 void TraceSwitch(ThreadState *thr);
847 uptr TraceTopPC(ThreadState *thr);
848 uptr TraceSize();
849 uptr TraceParts();
850 Trace *ThreadTrace(int tid);
851 
852 extern "C" void __tsan_trace_switch();
853 void ALWAYS_INLINE TraceAddEvent(ThreadState *thr, FastState fs,
854                                         EventType typ, u64 addr) {
855   if (!kCollectHistory)
856     return;
857   DCHECK_GE((int)typ, 0);
858   DCHECK_LE((int)typ, 7);
859   DCHECK_EQ(GetLsb(addr, kEventPCBits), addr);
860   StatInc(thr, StatEvents);
861   u64 pos = fs.GetTracePos();
862   if (UNLIKELY((pos % kTracePartSize) == 0)) {
863 #if !SANITIZER_GO
864     HACKY_CALL(__tsan_trace_switch);
865 #else
866     TraceSwitch(thr);
867 #endif
868   }
869   Event *trace = (Event*)GetThreadTrace(fs.tid());
870   Event *evp = &trace[pos];
871   Event ev = (u64)addr | ((u64)typ << kEventPCBits);
872   *evp = ev;
873 }
874 
875 #if !SANITIZER_GO
876 uptr ALWAYS_INLINE HeapEnd() {
877   return HeapMemEnd() + PrimaryAllocator::AdditionalSize();
878 }
879 #endif
880 
881 ThreadState *FiberCreate(ThreadState *thr, uptr pc, unsigned flags);
882 void FiberDestroy(ThreadState *thr, uptr pc, ThreadState *fiber);
883 void FiberSwitch(ThreadState *thr, uptr pc, ThreadState *fiber, unsigned flags);
884 
885 // These need to match __tsan_switch_to_fiber_* flags defined in
886 // tsan_interface.h. See documentation there as well.
887 enum FiberSwitchFlags {
888   FiberSwitchFlagNoSync = 1 << 0, // __tsan_switch_to_fiber_no_sync
889 };
890 
891 }  // namespace __tsan
892 
893 #endif  // TSAN_RTL_H
894