[TSan][compiler-rt] Defer symbolization of Reports to as late as possible (#151120)

This is the refactoring portion of:
#149516. My aim is for this
change to replicate current behaviour - just with Symbolization done
explicitly (and later than previously).

This change will enable us to perform symboliaztion after releasing the
locks in `OutputReport`; this is necessary on Apple platforms in order
to avoid a deadlock.

Author: DanBlackwell

compiler-rt/lib/tsan/rtl/tsan_report.h

@@ -12,6 +12,8 @@
 #ifndef TSAN_REPORT_H
 #define TSAN_REPORT_H
 
+#include "sanitizer_common/sanitizer_internal_defs.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
 #include "sanitizer_common/sanitizer_symbolizer.h"
 #include "sanitizer_common/sanitizer_thread_registry.h"
 #include "sanitizer_common/sanitizer_vector.h"
@@ -56,6 +58,7 @@ struct ReportMop {
   bool atomic;
   uptr external_tag;
   Vector<ReportMopMutex> mset;
+  StackTrace stack_trace;
   ReportStack *stack;
 
   ReportMop();
@@ -79,6 +82,7 @@ struct ReportLocation {
   int fd = 0;
   bool fd_closed = false;
   bool suppressable = false;
+  StackID stack_id = 0;
   ReportStack *stack = nullptr;
 };
 
@@ -89,22 +93,31 @@ struct ReportThread {
   ThreadType thread_type;
   char *name;
   Tid parent_tid;
+  StackID stack_id;
   ReportStack *stack;
+  bool suppressable;
 };
 
 struct ReportMutex {
   int id;
   uptr addr;
+  StackID stack_id;
   ReportStack *stack;
 };
 
+struct AddedLocationAddr {
+  uptr addr;
+  usize locs_idx;
+};
+
 class ReportDesc {
  public:
   ReportType typ;
   uptr tag;
   Vector<ReportStack*> stacks;
   Vector<ReportMop*> mops;
   Vector<ReportLocation*> locs;
+  Vector<AddedLocationAddr> added_location_addrs;
   Vector<ReportMutex*> mutexes;
   Vector<ReportThread*> threads;
   Vector<Tid> unique_tids;

compiler-rt/lib/tsan/rtl/tsan_rtl.h

@@ -420,6 +420,7 @@ class ScopedReportBase {
   void AddSleep(StackID stack_id);
   void SetCount(int count);
   void SetSigNum(int sig);
+  void SymbolizeStackElems(void);
 
   const ReportDesc *GetReport() const;
 
@@ -498,7 +499,7 @@ void ForkChildAfter(ThreadState *thr, uptr pc, bool start_thread);
 
 void ReportRace(ThreadState *thr, RawShadow *shadow_mem, Shadow cur, Shadow old,
                 AccessType typ);
-bool OutputReport(ThreadState *thr, const ScopedReport &srep);
+bool OutputReport(ThreadState *thr, ScopedReport &srep);
 bool IsFiredSuppression(Context *ctx, ReportType type, StackTrace trace);
 bool IsExpectedReport(uptr addr, uptr size);
 

compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cpp

@@ -539,13 +539,15 @@ void ReportDeadlock(ThreadState *thr, uptr pc, DDReport *r) {
   for (int i = 0; i < r->n; i++) {
     for (int j = 0; j < (flags()->second_deadlock_stack ? 2 : 1); j++) {
       u32 stk = r->loop[i].stk[j];
+      StackTrace stack;
       if (stk && stk != kInvalidStackID) {
-        rep.AddStack(StackDepotGet(stk), true);
+        stack = StackDepotGet(stk);
       } else {
         // Sometimes we fail to extract the stack trace (FIXME: investigate),
         // but we should still produce some stack trace in the report.
-        rep.AddStack(StackTrace(&dummy_pc, 1), true);
+        stack = StackTrace(&dummy_pc, 1);
       }
+      rep.AddStack(stack, true);
     }
   }
   OutputReport(thr, rep);

compiler-rt/lib/tsan/rtl/tsan_rtl_report.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_internal_defs.h"
 #include "sanitizer_common/sanitizer_libc.h"
 #include "sanitizer_common/sanitizer_placement_new.h"
 #include "sanitizer_common/sanitizer_stackdepot.h"
@@ -187,10 +188,8 @@ void ScopedReportBase::AddMemoryAccess(uptr addr, uptr external_tag, Shadow s,
   mop->size = size;
   mop->write = !(typ & kAccessRead);
   mop->atomic = typ & kAccessAtomic;
-  mop->stack = SymbolizeStack(stack);
   mop->external_tag = external_tag;
-  if (mop->stack)
-    mop->stack->suppressable = true;
+  mop->stack_trace = stack;
   for (uptr i = 0; i < mset->Size(); i++) {
     MutexSet::Desc d = mset->Get(i);
     int id = this->AddMutex(d.addr, d.stack_id);
@@ -199,6 +198,56 @@ void ScopedReportBase::AddMemoryAccess(uptr addr, uptr external_tag, Shadow s,
   }
 }
 
+void ScopedReportBase::SymbolizeStackElems() {
+  // symbolize memory ops
+  for (usize i = 0, size = rep_->mops.Size(); i < size; i++) {
+    ReportMop *mop = rep_->mops[i];
+    mop->stack = SymbolizeStack(mop->stack_trace);
+    if (mop->stack)
+      mop->stack->suppressable = true;
+  }
+
+  // symbolize locations
+  for (usize i = 0, size = rep_->locs.Size(); i < size; i++) {
+    // added locations have a NULL placeholder - don't dereference them
+    if (ReportLocation *loc = rep_->locs[i])
+      loc->stack = SymbolizeStackId(loc->stack_id);
+  }
+
+  // symbolize any added locations
+  for (usize i = 0, size = rep_->added_location_addrs.Size(); i < size; i++) {
+    AddedLocationAddr *added_loc = &rep_->added_location_addrs[i];
+    if (ReportLocation *loc = SymbolizeData(added_loc->addr)) {
+      loc->suppressable = true;
+      rep_->locs[added_loc->locs_idx] = loc;
+    }
+  }
+
+  // Filter out any added ___location placeholders that could not be symbolized
+  usize j = 0;
+  for (usize i = 0, size = rep_->locs.Size(); i < size; i++) {
+    if (rep_->locs[i] != nullptr) {
+      rep_->locs[j] = rep_->locs[i];
+      j++;
+    }
+  }
+  rep_->locs.Resize(j);
+
+  // symbolize threads
+  for (usize i = 0, size = rep_->threads.Size(); i < size; i++) {
+    ReportThread *rt = rep_->threads[i];
+    rt->stack = SymbolizeStackId(rt->stack_id);
+    if (rt->stack)
+      rt->stack->suppressable = rt->suppressable;
+  }
+
+  // symbolize mutexes
+  for (usize i = 0, size = rep_->mutexes.Size(); i < size; i++) {
+    ReportMutex *rm = rep_->mutexes[i];
+    rm->stack = SymbolizeStackId(rm->stack_id);
+  }
+}
+
 void ScopedReportBase::AddUniqueTid(Tid unique_tid) {
   rep_->unique_tids.PushBack(unique_tid);
 }
@@ -216,10 +265,8 @@ void ScopedReportBase::AddThread(const ThreadContext *tctx, bool suppressable) {
   rt->name = internal_strdup(tctx->name);
   rt->parent_tid = tctx->parent_tid;
   rt->thread_type = tctx->thread_type;
-  rt->stack = 0;
-  rt->stack = SymbolizeStackId(tctx->creation_stack_id);
-  if (rt->stack)
-    rt->stack->suppressable = suppressable;
+  rt->stack_id = tctx->creation_stack_id;
+  rt->suppressable = suppressable;
 }
 
 #if !SANITIZER_GO
@@ -270,7 +317,7 @@ int ScopedReportBase::AddMutex(uptr addr, StackID creation_stack_id) {
   rep_->mutexes.PushBack(rm);
   rm->id = rep_->mutexes.Size() - 1;
   rm->addr = addr;
-  rm->stack = SymbolizeStackId(creation_stack_id);
+  rm->stack_id = creation_stack_id;
   return rm->id;
 }
 
@@ -288,7 +335,7 @@ void ScopedReportBase::AddLocation(uptr addr, uptr size) {
     loc->fd_closed = closed;
     loc->fd = fd;
     loc->tid = creat_tid;
-    loc->stack = SymbolizeStackId(creat_stack);
+    loc->stack_id = creat_stack;
     rep_->locs.PushBack(loc);
     AddThread(creat_tid);
     return;
@@ -310,7 +357,7 @@ void ScopedReportBase::AddLocation(uptr addr, uptr size) {
     loc->heap_chunk_size = b->siz;
     loc->external_tag = b->tag;
     loc->tid = b->tid;
-    loc->stack = SymbolizeStackId(b->stk);
+    loc->stack_id = b->stk;
     rep_->locs.PushBack(loc);
     AddThread(b->tid);
     return;
@@ -324,11 +371,8 @@ void ScopedReportBase::AddLocation(uptr addr, uptr size) {
     AddThread(tctx);
   }
 #endif
-  if (ReportLocation *loc = SymbolizeData(addr)) {
-    loc->suppressable = true;
-    rep_->locs.PushBack(loc);
-    return;
-  }
+  rep_->added_location_addrs.PushBack({addr, rep_->locs.Size()});
+  rep_->locs.PushBack(nullptr);
 }
 
 #if !SANITIZER_GO
@@ -628,11 +672,12 @@ static bool HandleRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2]) {
   return false;
 }
 
-bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
+bool OutputReport(ThreadState *thr, ScopedReport &srep) {
   // These should have been checked in ShouldReport.
   // It's too late to check them here, we have already taken locks.
   CHECK(flags()->report_bugs);
   CHECK(!thr->suppress_reports);
+  srep.SymbolizeStackElems();
   atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
   const ReportDesc *rep = srep.GetReport();
   CHECK_EQ(thr->current_report, nullptr);