[Sanitizer] Make StackTrace a lightweight reference to array of PCs, and

introduce a BufferedStackTrace class, which owns this array.

Summary:
This change splits __sanitizer::StackTrace class into a lightweight
__sanitizer::StackTrace, which doesn't own array of PCs, and BufferedStackTrace,
which owns it. This would allow us to simplify the interface of StackDepot,
and eventually merge __sanitizer::StackTrace with __tsan::StackTrace.

Test Plan: regression test suite.

Reviewers: kcc, dvyukov

Reviewed By: dvyukov

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5985

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@220635 91177308-0d34-0410-b5e6-96231b3b80d8

7 files changed, 118 insertions, 119 deletions

diff --git a/lib/asan/asan_allocator.h b/lib/asan/asan_allocator.h
index d4e3daa4e..6d3a99282 100644
--- a/lib/asan/asan_allocator.h
+++ b/lib/asan/asan_allocator.h
@@ -45,8 +45,8 @@ class AsanChunkView {
   uptr AllocTid();
   uptr FreeTid();
   bool Eq(const AsanChunkView &c) const { return chunk_ == c.chunk_; }
-  void GetAllocStack(StackTrace *stack);
-  void GetFreeStack(StackTrace *stack);
+  StackTrace GetAllocStack();
+  StackTrace GetFreeStack();
   bool AddrIsInside(uptr addr, uptr access_size, sptr *offset) {
     if (addr >= Beg() && (addr + access_size) <= End()) {
       *offset = addr - Beg();
@@ -139,20 +139,20 @@ struct AsanThreadLocalMallocStorage {
   AsanThreadLocalMallocStorage() {}
 };
 
-void *asan_memalign(uptr alignment, uptr size, StackTrace *stack,
+void *asan_memalign(uptr alignment, uptr size, BufferedStackTrace *stack,
                     AllocType alloc_type);
-void asan_free(void *ptr, StackTrace *stack, AllocType alloc_type);
-void asan_sized_free(void *ptr, uptr size, StackTrace *stack,
+void asan_free(void *ptr, BufferedStackTrace *stack, AllocType alloc_type);
+void asan_sized_free(void *ptr, uptr size, BufferedStackTrace *stack,
                      AllocType alloc_type);
 
-void *asan_malloc(uptr size, StackTrace *stack);
-void *asan_calloc(uptr nmemb, uptr size, StackTrace *stack);
-void *asan_realloc(void *p, uptr size, StackTrace *stack);
-void *asan_valloc(uptr size, StackTrace *stack);
-void *asan_pvalloc(uptr size, StackTrace *stack);
+void *asan_malloc(uptr size, BufferedStackTrace *stack);
+void *asan_calloc(uptr nmemb, uptr size, BufferedStackTrace *stack);
+void *asan_realloc(void *p, uptr size, BufferedStackTrace *stack);
+void *asan_valloc(uptr size, BufferedStackTrace *stack);
+void *asan_pvalloc(uptr size, BufferedStackTrace *stack);
 
 int asan_posix_memalign(void **memptr, uptr alignment, uptr size,
-                          StackTrace *stack);
+                        BufferedStackTrace *stack);
 uptr asan_malloc_usable_size(void *ptr, uptr pc, uptr bp);
 
 uptr asan_mz_size(const void *ptr);
diff --git a/lib/asan/asan_allocator2.cc b/lib/asan/asan_allocator2.cc
index 27c25cfa5..687d5ba3f 100644
--- a/lib/asan/asan_allocator2.cc
+++ b/lib/asan/asan_allocator2.cc
@@ -182,20 +182,19 @@ uptr AsanChunkView::UsedSize() { return chunk_->UsedSize(); }
 uptr AsanChunkView::AllocTid() { return chunk_->alloc_tid; }
 uptr AsanChunkView::FreeTid() { return chunk_->free_tid; }
 
-static void GetStackTraceFromId(u32 id, StackTrace *stack) {
+static StackTrace GetStackTraceFromId(u32 id) {
   CHECK(id);
-  uptr size = 0;
-  const uptr *trace = StackDepotGet(id, &size);
-  CHECK(trace);
-  stack->CopyFrom(trace, size);
+  StackTrace res = StackDepotGet(id);
+  CHECK(res.trace);
+  return res;
 }
 
-void AsanChunkView::GetAllocStack(StackTrace *stack) {
-  GetStackTraceFromId(chunk_->alloc_context_id, stack);
+StackTrace AsanChunkView::GetAllocStack() {
+  return GetStackTraceFromId(chunk_->alloc_context_id);
 }
 
-void AsanChunkView::GetFreeStack(StackTrace *stack) {
-  GetStackTraceFromId(chunk_->free_context_id, stack);
+StackTrace AsanChunkView::GetFreeStack() {
+  return GetStackTraceFromId(chunk_->free_context_id);
 }
 
 struct QuarantineCallback;
@@ -263,7 +262,7 @@ void ReInitializeAllocator() {
   quarantine.Init((uptr)flags()->quarantine_size, kMaxThreadLocalQuarantine);
 }
 
-static void *Allocate(uptr size, uptr alignment, StackTrace *stack,
+static void *Allocate(uptr size, uptr alignment, BufferedStackTrace *stack,
                       AllocType alloc_type, bool can_fill) {
   if (UNLIKELY(!asan_inited))
     AsanInitFromRtl();
@@ -391,15 +390,16 @@ static void *Allocate(uptr size, uptr alignment, StackTrace *stack,
   return res;
 }
 
-static void ReportInvalidFree(void *ptr, u8 chunk_state, StackTrace *stack) {
+static void ReportInvalidFree(void *ptr, u8 chunk_state,
+                              BufferedStackTrace *stack) {
   if (chunk_state == CHUNK_QUARANTINE)
     ReportDoubleFree((uptr)ptr, stack);
   else
     ReportFreeNotMalloced((uptr)ptr, stack);
 }
 
-static void AtomicallySetQuarantineFlag(AsanChunk *m,
-                                        void *ptr, StackTrace *stack) {
+static void AtomicallySetQuarantineFlag(AsanChunk *m, void *ptr,
+                                        BufferedStackTrace *stack) {
   u8 old_chunk_state = CHUNK_ALLOCATED;
   // Flip the chunk_state atomically to avoid race on double-free.
   if (!atomic_compare_exchange_strong((atomic_uint8_t*)m, &old_chunk_state,
@@ -410,8 +410,8 @@ static void AtomicallySetQuarantineFlag(AsanChunk *m,
 
 // Expects the chunk to already be marked as quarantined by using
 // AtomicallySetQuarantineFlag.
-static void QuarantineChunk(AsanChunk *m, void *ptr,
-                            StackTrace *stack, AllocType alloc_type) {
+static void QuarantineChunk(AsanChunk *m, void *ptr, BufferedStackTrace *stack,
+                            AllocType alloc_type) {
   CHECK_EQ(m->chunk_state, CHUNK_QUARANTINE);
 
   if (m->alloc_type != alloc_type && flags()->alloc_dealloc_mismatch)
@@ -447,7 +447,7 @@ static void QuarantineChunk(AsanChunk *m, void *ptr,
   }
 }
 
-static void Deallocate(void *ptr, uptr delete_size, StackTrace *stack,
+static void Deallocate(void *ptr, uptr delete_size, BufferedStackTrace *stack,
                        AllocType alloc_type) {
   uptr p = reinterpret_cast<uptr>(ptr);
   if (p == 0) return;
@@ -464,7 +464,8 @@ static void Deallocate(void *ptr, uptr delete_size, StackTrace *stack,
   QuarantineChunk(m, ptr, stack, alloc_type);
 }
 
-static void *Reallocate(void *old_ptr, uptr new_size, StackTrace *stack) {
+static void *Reallocate(void *old_ptr, uptr new_size,
+                        BufferedStackTrace *stack) {
   CHECK(old_ptr && new_size);
   uptr p = reinterpret_cast<uptr>(old_ptr);
   uptr chunk_beg = p - kChunkHeaderSize;
@@ -577,25 +578,25 @@ void PrintInternalAllocatorStats() {
   allocator.PrintStats();
 }
 
-void *asan_memalign(uptr alignment, uptr size, StackTrace *stack,
+void *asan_memalign(uptr alignment, uptr size, BufferedStackTrace *stack,
                     AllocType alloc_type) {
   return Allocate(size, alignment, stack, alloc_type, true);
 }
 
-void asan_free(void *ptr, StackTrace *stack, AllocType alloc_type) {
+void asan_free(void *ptr, BufferedStackTrace *stack, AllocType alloc_type) {
   Deallocate(ptr, 0, stack, alloc_type);
 }
 
-void asan_sized_free(void *ptr, uptr size, StackTrace *stack,
+void asan_sized_free(void *ptr, uptr size, BufferedStackTrace *stack,
                      AllocType alloc_type) {
   Deallocate(ptr, size, stack, alloc_type);
 }
 
-void *asan_malloc(uptr size, StackTrace *stack) {
+void *asan_malloc(uptr size, BufferedStackTrace *stack) {
   return Allocate(size, 8, stack, FROM_MALLOC, true);
 }
 
-void *asan_calloc(uptr nmemb, uptr size, StackTrace *stack) {
+void *asan_calloc(uptr nmemb, uptr size, BufferedStackTrace *stack) {
   if (CallocShouldReturnNullDueToOverflow(size, nmemb))
     return AllocatorReturnNull();
   void *ptr = Allocate(nmemb * size, 8, stack, FROM_MALLOC, false);
@@ -606,7 +607,7 @@ void *asan_calloc(uptr nmemb, uptr size, StackTrace *stack) {
   return ptr;
 }
 
-void *asan_realloc(void *p, uptr size, StackTrace *stack) {
+void *asan_realloc(void *p, uptr size, BufferedStackTrace *stack) {
   if (p == 0)
     return Allocate(size, 8, stack, FROM_MALLOC, true);
   if (size == 0) {
@@ -616,11 +617,11 @@ void *asan_realloc(void *p, uptr size, StackTrace *stack) {
   return Reallocate(p, size, stack);
 }
 
-void *asan_valloc(uptr size, StackTrace *stack) {
+void *asan_valloc(uptr size, BufferedStackTrace *stack) {
   return Allocate(size, GetPageSizeCached(), stack, FROM_MALLOC, true);
 }
 
-void *asan_pvalloc(uptr size, StackTrace *stack) {
+void *asan_pvalloc(uptr size, BufferedStackTrace *stack) {
   uptr PageSize = GetPageSizeCached();
   size = RoundUpTo(size, PageSize);
   if (size == 0) {
@@ -631,7 +632,7 @@ void *asan_pvalloc(uptr size, StackTrace *stack) {
 }
 
 int asan_posix_memalign(void **memptr, uptr alignment, uptr size,
-                        StackTrace *stack) {
+                        BufferedStackTrace *stack) {
   void *ptr = Allocate(size, alignment, stack, FROM_MALLOC, true);
   CHECK(IsAligned((uptr)ptr, alignment));
   *memptr = ptr;
diff --git a/lib/asan/asan_debugging.cc b/lib/asan/asan_debugging.cc
index ca5fa1f75..2b66dd526 100644
--- a/lib/asan/asan_debugging.cc
+++ b/lib/asan/asan_debugging.cc
@@ -86,22 +86,19 @@ uptr AsanGetStack(uptr addr, uptr *trace, uptr size, u32 *thread_id,
   AsanChunkView chunk = FindHeapChunkByAddress(addr);
   if (!chunk.IsValid()) return 0;
 
-  StackTrace stack;
+  StackTrace stack(nullptr, 0);
   if (alloc_stack) {
     if (chunk.AllocTid() == kInvalidTid) return 0;
-    chunk.GetAllocStack(&stack);
+    stack = chunk.GetAllocStack();
     if (thread_id) *thread_id = chunk.AllocTid();
   } else {
     if (chunk.FreeTid() == kInvalidTid) return 0;
-    chunk.GetFreeStack(&stack);
+    stack = chunk.GetFreeStack();
     if (thread_id) *thread_id = chunk.FreeTid();
   }
 
   if (trace && size) {
-    if (size > kStackTraceMax)
-      size = kStackTraceMax;
-    if (size > stack.size)
-      size = stack.size;
+    size = Min(size, Min(stack.size, kStackTraceMax));
     for (uptr i = 0; i < size; i++)
       trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]);
 
diff --git a/lib/asan/asan_report.cc b/lib/asan/asan_report.cc
index b42d9bc5c..2ca11a314 100644
--- a/lib/asan/asan_report.cc
+++ b/lib/asan/asan_report.cc
@@ -440,16 +440,15 @@ bool DescribeAddressIfStack(uptr addr, uptr access_size) {
   // previously. That's unfortunate, but I have no better solution,
   // especially given that the alloca may be from entirely different place
   // (e.g. use-after-scope, or different thread's stack).
-  StackTrace alloca_stack;
 #if defined(__powerpc64__) && defined(__BIG_ENDIAN__)
   // On PowerPC64 ELFv1, the address of a function actually points to a
   // three-doubleword data structure with the first field containing
   // the address of the function's code.
   access.frame_pc = *reinterpret_cast<uptr *>(access.frame_pc);
 #endif
-  alloca_stack.trace[0] = access.frame_pc + 16;
-  alloca_stack.size = 1;
+  access.frame_pc += 16;
   Printf("%s", d.EndLocation());
+  StackTrace alloca_stack(&access.frame_pc, 1);
   alloca_stack.Print();
 
   InternalMmapVector<StackVarDescr> vars(16);
@@ -519,8 +518,7 @@ void DescribeHeapAddress(uptr addr, uptr access_size) {
   asanThreadRegistry().CheckLocked();
   AsanThreadContext *alloc_thread =
       GetThreadContextByTidLocked(chunk.AllocTid());
-  StackTrace alloc_stack;
-  chunk.GetAllocStack(&alloc_stack);
+  StackTrace alloc_stack = chunk.GetAllocStack();
   char tname[128];
   Decorator d;
   AsanThreadContext *free_thread = 0;
@@ -530,8 +528,7 @@ void DescribeHeapAddress(uptr addr, uptr access_size) {
            free_thread->tid,
            ThreadNameWithParenthesis(free_thread, tname, sizeof(tname)),
            d.EndAllocation());
-    StackTrace free_stack;
-    chunk.GetFreeStack(&free_stack);
+    StackTrace free_stack = chunk.GetFreeStack();
     free_stack.Print();
     Printf("%spreviously allocated by thread T%d%s here:%s\n",
            d.Allocation(), alloc_thread->tid,
@@ -581,9 +578,7 @@ void DescribeThread(AsanThreadContext *context) {
       " created by T%d%s here:\n", context->parent_tid,
       ThreadNameWithParenthesis(context->parent_tid, tname, sizeof(tname)));
   Printf("%s", str.data());
-  uptr stack_size;
-  const uptr *stack_trace = StackDepotGet(context->stack_id, &stack_size);
-  StackTrace::PrintStack(stack_trace, stack_size);
+  StackDepotGet(context->stack_id).Print();
   // Recursively described parent thread if needed.
   if (flags()->print_full_thread_history) {
     AsanThreadContext *parent_context =
@@ -684,7 +679,7 @@ void ReportSIGSEGV(const char *description, uptr pc, uptr sp, uptr bp,
   ReportErrorSummary("SEGV", &stack);
 }
 
-void ReportDoubleFree(uptr addr, StackTrace *free_stack) {
+void ReportDoubleFree(uptr addr, BufferedStackTrace *free_stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
@@ -703,7 +698,7 @@ void ReportDoubleFree(uptr addr, StackTrace *free_stack) {
 }
 
 void ReportNewDeleteSizeMismatch(uptr addr, uptr delete_size,
-                                 StackTrace *free_stack) {
+                                 BufferedStackTrace *free_stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
@@ -726,7 +721,7 @@ void ReportNewDeleteSizeMismatch(uptr addr, uptr delete_size,
          "ASAN_OPTIONS=new_delete_type_mismatch=0\n");
 }
 
-void ReportFreeNotMalloced(uptr addr, StackTrace *free_stack) {
+void ReportFreeNotMalloced(uptr addr, BufferedStackTrace *free_stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
@@ -743,7 +738,7 @@ void ReportFreeNotMalloced(uptr addr, StackTrace *free_stack) {
   ReportErrorSummary("bad-free", &stack);
 }
 
-void ReportAllocTypeMismatch(uptr addr, StackTrace *free_stack,
+void ReportAllocTypeMismatch(uptr addr, BufferedStackTrace *free_stack,
                              AllocType alloc_type,
                              AllocType dealloc_type) {
   static const char *alloc_names[] =
@@ -766,7 +761,7 @@ void ReportAllocTypeMismatch(uptr addr, StackTrace *free_stack,
          "ASAN_OPTIONS=alloc_dealloc_mismatch=0\n");
 }
 
-void ReportMallocUsableSizeNotOwned(uptr addr, StackTrace *stack) {
+void ReportMallocUsableSizeNotOwned(uptr addr, BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
@@ -779,7 +774,8 @@ void ReportMallocUsableSizeNotOwned(uptr addr, StackTrace *stack) {
   ReportErrorSummary("bad-malloc_usable_size", stack);
 }
 
-void ReportSanitizerGetAllocatedSizeNotOwned(uptr addr, StackTrace *stack) {
+void ReportSanitizerGetAllocatedSizeNotOwned(uptr addr,
+                                             BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
@@ -792,9 +788,10 @@ void ReportSanitizerGetAllocatedSizeNotOwned(uptr addr, StackTrace *stack) {
   ReportErrorSummary("bad-__sanitizer_get_allocated_size", stack);
 }
 
-void ReportStringFunctionMemoryRangesOverlap(
-    const char *function, const char *offset1, uptr length1,
-    const char *offset2, uptr length2, StackTrace *stack) {
+void ReportStringFunctionMemoryRangesOverlap(const char *function,
+                                             const char *offset1, uptr length1,
+                                             const char *offset2, uptr length2,
+                                             BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   char bug_type[100];
@@ -811,7 +808,7 @@ void ReportStringFunctionMemoryRangesOverlap(
 }
 
 void ReportStringFunctionSizeOverflow(uptr offset, uptr size,
-                                      StackTrace *stack) {
+                                      BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   const char *bug_type = "negative-size-param";
@@ -825,7 +822,7 @@ void ReportStringFunctionSizeOverflow(uptr offset, uptr size,
 
 void ReportBadParamsToAnnotateContiguousContainer(uptr beg, uptr end,
                                                   uptr old_mid, uptr new_mid,
-                                                  StackTrace *stack) {
+                                                  BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Report("ERROR: AddressSanitizer: bad parameters to "
          "__sanitizer_annotate_contiguous_container:\n"
@@ -855,12 +852,9 @@ void ReportODRViolation(const __asan_global *g1, u32 stack_id1,
   if (stack_id1 && stack_id2) {
     Printf("These globals were registered at these points:\n");
     Printf("  [1]:\n");
-    uptr stack_size;
-    const uptr *stack_trace = StackDepotGet(stack_id1, &stack_size);
-    StackTrace::PrintStack(stack_trace, stack_size);
+    StackDepotGet(stack_id1).Print();
     Printf("  [2]:\n");
-    stack_trace = StackDepotGet(stack_id2, &stack_size);
-    StackTrace::PrintStack(stack_trace, stack_size);
+    StackDepotGet(stack_id2).Print();
   }
   Report("HINT: if you don't care about these warnings you may set "
          "ASAN_OPTIONS=detect_odr_violation=0\n");
@@ -900,8 +894,8 @@ static INLINE void CheckForInvalidPointerPair(void *p1, void *p2) {
 }
 // ----------------------- Mac-specific reports ----------------- {{{1
 
-void WarnMacFreeUnallocated(
-    uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack) {
+void WarnMacFreeUnallocated(uptr addr, uptr zone_ptr, const char *zone_name,
+                            BufferedStackTrace *stack) {
   // Just print a warning here.
   Printf("free_common(%p) -- attempting to free unallocated memory.\n"
              "AddressSanitizer is ignoring this error on Mac OS now.\n",
@@ -911,8 +905,8 @@ void WarnMacFreeUnallocated(
   DescribeHeapAddress(addr, 1);
 }
 
-void ReportMacMzReallocUnknown(
-    uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack) {
+void ReportMacMzReallocUnknown(uptr addr, uptr zone_ptr, const char *zone_name,
+                               BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Printf("mz_realloc(%p) -- attempting to realloc unallocated memory.\n"
              "This is an unrecoverable problem, exiting now.\n",
@@ -922,8 +916,8 @@ void ReportMacMzReallocUnknown(
   DescribeHeapAddress(addr, 1);
 }
 
-void ReportMacCfReallocUnknown(
-    uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack) {
+void ReportMacCfReallocUnknown(uptr addr, uptr zone_ptr, const char *zone_name,
+                               BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Printf("cf_realloc(%p) -- attempting to realloc unallocated memory.\n"
              "This is an unrecoverable problem, exiting now.\n",
diff --git a/lib/asan/asan_report.h b/lib/asan/asan_report.h
index 48fb52987..fd65bad95 100644
--- a/lib/asan/asan_report.h
+++ b/lib/asan/asan_report.h
@@ -57,35 +57,41 @@ void NORETURN
 void NORETURN ReportSIGSEGV(const char *description, uptr pc, uptr sp, uptr bp,
                             void *context, uptr addr);
 void NORETURN ReportNewDeleteSizeMismatch(uptr addr, uptr delete_size,
-                                          StackTrace *free_stack);
-void NORETURN ReportDoubleFree(uptr addr, StackTrace *free_stack);
-void NORETURN ReportFreeNotMalloced(uptr addr, StackTrace *free_stack);
-void NORETURN ReportAllocTypeMismatch(uptr addr, StackTrace *free_stack,
+                                          BufferedStackTrace *free_stack);
+void NORETURN ReportDoubleFree(uptr addr, BufferedStackTrace *free_stack);
+void NORETURN ReportFreeNotMalloced(uptr addr, BufferedStackTrace *free_stack);
+void NORETURN ReportAllocTypeMismatch(uptr addr, BufferedStackTrace *free_stack,
                                       AllocType alloc_type,
                                       AllocType dealloc_type);
-void NORETURN ReportMallocUsableSizeNotOwned(uptr addr,
-                                             StackTrace *stack);
 void NORETURN
-ReportSanitizerGetAllocatedSizeNotOwned(uptr addr, StackTrace *stack);
-void NORETURN ReportStringFunctionMemoryRangesOverlap(
-    const char *function, const char *offset1, uptr length1,
-    const char *offset2, uptr length2, StackTrace *stack);
+    ReportMallocUsableSizeNotOwned(uptr addr, BufferedStackTrace *stack);
 void NORETURN
-ReportStringFunctionSizeOverflow(uptr offset, uptr size, StackTrace *stack);
+    ReportSanitizerGetAllocatedSizeNotOwned(uptr addr,
+                                            BufferedStackTrace *stack);
 void NORETURN
-ReportBadParamsToAnnotateContiguousContainer(uptr beg, uptr end, uptr old_mid,
-                                             uptr new_mid, StackTrace *stack);
+    ReportStringFunctionMemoryRangesOverlap(const char *function,
+                                            const char *offset1, uptr length1,
+                                            const char *offset2, uptr length2,
+                                            BufferedStackTrace *stack);
+void NORETURN ReportStringFunctionSizeOverflow(uptr offset, uptr size,
+                                               BufferedStackTrace *stack);
+void NORETURN
+    ReportBadParamsToAnnotateContiguousContainer(uptr beg, uptr end,
+                                                 uptr old_mid, uptr new_mid,
+                                                 BufferedStackTrace *stack);
 
 void NORETURN
 ReportODRViolation(const __asan_global *g1, u32 stack_id1,
                    const __asan_global *g2, u32 stack_id2);
 
 // Mac-specific errors and warnings.
-void WarnMacFreeUnallocated(
-    uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack);
-void NORETURN ReportMacMzReallocUnknown(
-    uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack);
-void NORETURN ReportMacCfReallocUnknown(
-    uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack);
+void WarnMacFreeUnallocated(uptr addr, uptr zone_ptr, const char *zone_name,
+                            BufferedStackTrace *stack);
+void NORETURN ReportMacMzReallocUnknown(uptr addr, uptr zone_ptr,
+                                        const char *zone_name,
+                                        BufferedStackTrace *stack);
+void NORETURN ReportMacCfReallocUnknown(uptr addr, uptr zone_ptr,
+                                        const char *zone_name,
+                                        BufferedStackTrace *stack);
 
 }  // namespace __asan
diff --git a/lib/asan/asan_stack.h b/lib/asan/asan_stack.h
index 884f0776a..7cee75528 100644
--- a/lib/asan/asan_stack.h
+++ b/lib/asan/asan_stack.h
@@ -25,8 +25,9 @@ namespace __asan {
 // The pc will be in the position 0 of the resulting stack trace.
 // The bp may refer to the current frame or to the caller's frame.
 ALWAYS_INLINE
-void GetStackTraceWithPcBpAndContext(StackTrace *stack, uptr max_depth, uptr pc,
-                                     uptr bp, void *context, bool fast) {
+void GetStackTraceWithPcBpAndContext(BufferedStackTrace *stack, uptr max_depth,
+                                     uptr pc, uptr bp, void *context,
+                                     bool fast) {
 #if SANITIZER_WINDOWS
   stack->Unwind(max_depth, pc, bp, context, 0, 0, fast);
 #else
@@ -53,14 +54,14 @@ void GetStackTraceWithPcBpAndContext(StackTrace *stack, uptr max_depth, uptr pc,
 // don't want stack trace to contain functions from ASan internals.
 
 #define GET_STACK_TRACE(max_size, fast)                                        \
-  StackTrace stack;                                                            \
+  BufferedStackTrace stack;                                                    \
   if (max_size <= 2) {                                                         \
     stack.size = max_size;                                                     \
     if (max_size > 0) {                                                        \
       stack.top_frame_bp = GET_CURRENT_FRAME();                                \
-      stack.trace[0] = StackTrace::GetCurrentPc();                             \
+      stack.trace_buffer[0] = StackTrace::GetCurrentPc();                      \
       if (max_size > 1)                                                        \
-        stack.trace[1] = GET_CALLER_PC();                                      \
+        stack.trace_buffer[1] = GET_CALLER_PC();                               \
     }                                                                          \
   } else {                                                                     \
     GetStackTraceWithPcBpAndContext(&stack, max_size,                          \
@@ -69,12 +70,12 @@ void GetStackTraceWithPcBpAndContext(StackTrace *stack, uptr max_depth, uptr pc,
   }
 
 #define GET_STACK_TRACE_FATAL(pc, bp)                                          \
-  StackTrace stack;                                                            \
+  BufferedStackTrace stack;                                                    \
   GetStackTraceWithPcBpAndContext(&stack, kStackTraceMax, pc, bp, 0,           \
                                   common_flags()->fast_unwind_on_fatal)
 
 #define GET_STACK_TRACE_SIGNAL(pc, bp, context)                                \
-  StackTrace stack;                                                            \
+  BufferedStackTrace stack;                                                    \
   GetStackTraceWithPcBpAndContext(&stack, kStackTraceMax, pc, bp, context,     \
                                   common_flags()->fast_unwind_on_fatal)
 
diff --git a/lib/asan/tests/asan_noinst_test.cc b/lib/asan/tests/asan_noinst_test.cc
index 7fae462a7..bb6af45bd 100644
--- a/lib/asan/tests/asan_noinst_test.cc
+++ b/lib/asan/tests/asan_noinst_test.cc
@@ -52,19 +52,19 @@ TEST(AddressSanitizer, InternalSimpleDeathTest) {
 
 static void MallocStress(size_t n) {
   u32 seed = my_rand();
-  StackTrace stack1;
-  stack1.trace[0] = 0xa123;
-  stack1.trace[1] = 0xa456;
+  BufferedStackTrace stack1;
+  stack1.trace_buffer[0] = 0xa123;
+  stack1.trace_buffer[1] = 0xa456;
   stack1.size = 2;
 
-  StackTrace stack2;
-  stack2.trace[0] = 0xb123;
-  stack2.trace[1] = 0xb456;
+  BufferedStackTrace stack2;
+  stack2.trace_buffer[0] = 0xb123;
+  stack2.trace_buffer[1] = 0xb456;
   stack2.size = 2;
 
-  StackTrace stack3;
-  stack3.trace[0] = 0xc123;
-  stack3.trace[1] = 0xc456;
+  BufferedStackTrace stack3;
+  stack3.trace_buffer[0] = 0xc123;
+  stack3.trace_buffer[1] = 0xc456;
   stack3.size = 2;
 
   std::vector<void *> vec;
@@ -140,8 +140,8 @@ TEST(AddressSanitizer, DISABLED_InternalPrintShadow) {
 }
 
 TEST(AddressSanitizer, QuarantineTest) {
-  StackTrace stack;
-  stack.trace[0] = 0x890;
+  BufferedStackTrace stack;
+  stack.trace_buffer[0] = 0x890;
   stack.size = 1;
 
   const int size = 1024;
@@ -161,8 +161,8 @@ TEST(AddressSanitizer, QuarantineTest) {
 void *ThreadedQuarantineTestWorker(void *unused) {
   (void)unused;
   u32 seed = my_rand();
-  StackTrace stack;
-  stack.trace[0] = 0x890;
+  BufferedStackTrace stack;
+  stack.trace_buffer[0] = 0x890;
   stack.size = 1;
 
   for (size_t i = 0; i < 1000; i++) {
@@ -188,8 +188,8 @@ TEST(AddressSanitizer, ThreadedQuarantineTest) {
 
 void *ThreadedOneSizeMallocStress(void *unused) {
   (void)unused;
-  StackTrace stack;
-  stack.trace[0] = 0x890;
+  BufferedStackTrace stack;
+  stack.trace_buffer[0] = 0x890;
   stack.size = 1;
   const size_t kNumMallocs = 1000;
   for (int iter = 0; iter < 1000; iter++) {
@@ -241,8 +241,8 @@ TEST(AddressSanitizer, LoadStoreCallbacks) {
   uptr buggy_ptr;
 
   __asan_test_only_reported_buggy_pointer = &buggy_ptr;
-  StackTrace stack;
-  stack.trace[0] = 0x890;
+  BufferedStackTrace stack;
+  stack.trace_buffer[0] = 0x890;
   stack.size = 1;
 
   for (uptr len = 16; len <= 32; len++) {