Split DescribeAddressIf* (and DescribeHeapAddress) between a function that gets all the information (structured), and one that prints it.

[filcab]

Summary

This is the first patch to start reifying information about errors. It deals only with reifying address-related information.
It will allow us to generate structures with all the relevant information for a given error so a debugger can get to them or they can be included in a core dump.

Additional changes:
Move the Decorator to asan_descriptions.h
Move ThreadNameWithParenthesis and DescribeThread to asan_descriptions.cc
Convert AsanLocateAddress to Get*AddressInformation functions.

[kcc]

This is a large change and will take quadratic time for review.
Please help me speed it up by splitting the change into several.
Especially, separate simple refactoring (moving code around that does not change functionality) from actual changes in the code (even renaming functions).

[filcab]

Abandoning, since this revision will be split in several ones to ease reviewing.

lib/asan/CMakeLists.txt

 # Build for the AddressSanitizer runtime support library.
 
 set(ASAN_SOURCES
   asan_allocator.cc
   asan_activation.cc
   asan_debugging.cc
+  asan_descriptions.cc
   asan_fake_stack.cc
   asan_flags.cc
   asan_globals.cc
   asan_interceptors.cc
   asan_linux.cc
   asan_mac.cc
   asan_malloc_linux.cc
   asan_malloc_mac.cc

lib/asan/asan_allocator.h

public:
   uptr UsedSize();       // Size requested by the user.
   uptr AllocTid();
   uptr FreeTid();
   bool Eq(const AsanChunkView &c) const { return chunk_ == c.chunk_; }
   u32 GetAllocStackId();
   u32 GetFreeStackId();
   StackTrace GetAllocStack();
   StackTrace GetFreeStack();
+  AllocType AllocType();
   bool AddrIsInside(uptr addr, uptr access_size, sptr *offset) {
     if (addr >= Beg() && (addr + access_size) <= End()) {
       *offset = addr - Beg();
       return true;
     }
     return false;
   }
   bool AddrIsAtLeft(uptr addr, uptr access_size, sptr *offset) {

lib/asan/asan_allocator.cc

 bool AsanChunkView::IsAllocated() {
   return chunk_ && chunk_->chunk_state == CHUNK_ALLOCATED;
 }
 uptr AsanChunkView::Beg() { return chunk_->Beg(); }
 uptr AsanChunkView::End() { return Beg() + UsedSize(); }
 uptr AsanChunkView::UsedSize() { return chunk_->UsedSize(); }
 uptr AsanChunkView::AllocTid() { return chunk_->alloc_tid; }
 uptr AsanChunkView::FreeTid() { return chunk_->free_tid; }
+AllocType AsanChunkView::AllocType() {
+  return (enum AllocType)chunk_->alloc_type;
+}
 
 static StackTrace GetStackTraceFromId(u32 id) {
   CHECK(id);
   StackTrace res = StackDepotGet(id);
   CHECK(res.trace);
   return res;
 }
 

lib/asan/asan_debugging.cc

 //===-- asan_debugging.cc -------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of AddressSanitizer, an address sanity checker.
 //
 // This file contains various functions that are generally useful to call when
 // using a debugger (LLDB, GDB).
 //===----------------------------------------------------------------------===//
 
 #include "asan_allocator.h"
+#include "asan_descriptions.h"
 #include "asan_flags.h"
 #include "asan_internal.h"
 #include "asan_mapping.h"
 #include "asan_report.h"
 #include "asan_thread.h"
 
-namespace __asan {
-
-void GetInfoForStackVar(uptr addr, AddressDescription *descr, AsanThread *t) {
-  descr->name[0] = 0;
-  descr->region_address = 0;
-  descr->region_size = 0;
-  descr->region_kind = "stack";
+namespace {
+using namespace __asan;
 
-  AsanThread::StackFrameAccess access;
-  if (!t->GetStackFrameAccessByAddr(addr, &access))
-    return;
+void FindInfoForStackVar(uptr addr, const char *frame_descr, uptr offset,
+                         AddressDescription *descr) {
   InternalMmapVector<StackVarDescr> vars(16);
-  if (!ParseFrameDescription(access.frame_descr, &vars)) {
+  if (!ParseFrameDescription(frame_descr, &vars)) {
     return;
   }
 
   for (uptr i = 0; i < vars.size(); i++) {
-    if (access.offset <= vars[i].beg + vars[i].size) {
-      internal_strncat(descr->name, vars[i].name_pos,
-                       Min(descr->name_size, vars[i].name_len));
-      descr->region_address = addr - (access.offset - vars[i].beg);
+    if (offset <= vars[i].beg + vars[i].size) {
+      // We use name_len + 1 because strlcpy will guarantee a \0 at the end, so
+      // if we're limiting the copy due to name_len, we add 1 to ensure we copy
+      // the whole name and then terminate with '\0'.
+      internal_strlcpy(descr->name, vars[i].name_pos,
+                       Min(descr->name_size, vars[i].name_len + 1));
+      descr->region_address = addr - (offset - vars[i].beg);
       descr->region_size = vars[i].size;
       return;
     }
   }
 }
 
-void GetInfoForHeapAddress(uptr addr, AddressDescription *descr) {
-  AsanChunkView chunk = FindHeapChunkByAddress(addr);
-
-  descr->name[0] = 0;
-  descr->region_address = 0;
-  descr->region_size = 0;
-
-  if (!chunk.IsValid()) {
-    descr->region_kind = "heap-invalid";
+void AsanLocateAddress(uptr addr, AddressDescription *descr) {
+  ShadowAddressDescription shadow_descr;
+  if (GetShadowAddressInformation(addr, &shadow_descr)) {
+    descr->region_kind = ShadowNames[shadow_descr.kind];
     return;
   }
-
-  descr->region_address = chunk.Beg();
-  descr->region_size = chunk.UsedSize();
-  descr->region_kind = "heap";
+  GlobalAddressDescription global_descr;
+  if (GetGlobalAddressInformation(addr, &global_descr)) {
+    descr->region_kind = "global";
+    auto &g = global_descr.globals[0];
+    internal_strlcpy(descr->name, g.name, descr->name_size);
+    descr->region_address = g.beg;
+    descr->region_size = g.size;
+    return;
   }
 
-void AsanLocateAddress(uptr addr, AddressDescription *descr) {
-  if (DescribeAddressIfShadow(addr, descr, /* print */ false)) {
-    return;
+  StackAddressDescription stack_descr;
+  asanThreadRegistry().Lock();
+  if (GetStackAddressInformation(addr, &stack_descr)) {
+    asanThreadRegistry().Unlock();
+    descr->region_kind = "stack";
+    if (!stack_descr.frame_descr) {
+      descr->name[0] = 0;
+      descr->region_address = 0;
+      descr->region_size = 0;
+    } else {
+      FindInfoForStackVar(addr, stack_descr.frame_descr, stack_descr.offset,
+                          descr);
     }
-  if (GetInfoForAddressIfGlobal(addr, descr)) {
     return;
   }
-  asanThreadRegistry().Lock();
-  AsanThread *thread = FindThreadByStackAddress(addr);
   asanThreadRegistry().Unlock();
-  if (thread) {
-    GetInfoForStackVar(addr, descr, thread);
+
+  descr->name[0] = 0;
+  HeapAddressDescription heap_descr;
+  if (GetHeapAddressInformation(addr, 1, &heap_descr)) {
+    descr->region_address = heap_descr.chunk_access.chunk_begin;
+    descr->region_size = heap_descr.chunk_access.chunk_size;
+    descr->region_kind = "heap";
     return;
   }
-  GetInfoForHeapAddress(addr, descr);
+
+  descr->region_address = 0;
+  descr->region_size = 0;
+  descr->region_kind = "heap-invalid";
 }
 
-static uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id,
+uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id,
                          bool alloc_stack) {
   AsanChunkView chunk = FindHeapChunkByAddress(addr);
   if (!chunk.IsValid()) return 0;
 
   StackTrace stack(nullptr, 0);
   if (alloc_stack) {
     if (chunk.AllocTid() == kInvalidTid) return 0;
     stack = chunk.GetAllocStack();
for (uptr i = 0; i < size; i++)
       trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]);
 
     return size;
   }
 
   return 0;
 }
 
-} // namespace __asan
-
-using namespace __asan;
+}  // namespace
 
 SANITIZER_INTERFACE_ATTRIBUTE
 const char *__asan_locate_address(uptr addr, char *name, uptr name_size,
                                   uptr *region_address, uptr *region_size) {
   AddressDescription descr = { name, name_size, 0, 0, nullptr };
   AsanLocateAddress(addr, &descr);
   if (region_address) *region_address = descr.region_address;
   if (region_size) *region_size = descr.region_size;

lib/asan/asan_descriptions.h

+//===-- asan_descriptions.h -------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// ASan-private header for asan_descriptions.cc.
+// TODO(filcab): Most struct definitions should move to the interface headers.
+//===----------------------------------------------------------------------===//
+
+#include "asan_allocator.h"
+#include "asan_thread.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_report_decorator.h"
+
+namespace __asan {
+
+void DescribeThread(AsanThreadContext *context);
+static inline void DescribeThread(AsanThread *t) {
+  if (t) DescribeThread(t->context());
+}
+const char *ThreadNameWithParenthesis(AsanThreadContext *t, char buff[],
+                                      uptr buff_len);
+const char *ThreadNameWithParenthesis(u32 tid, char buff[], uptr buff_len);
+
+class Decorator : public __sanitizer::SanitizerCommonDecorator {
+ public:
+  Decorator() : SanitizerCommonDecorator() {}
+  const char *Access() { return Blue(); }
+  const char *EndAccess() { return Default(); }
+  const char *Location() { return Green(); }
+  const char *EndLocation() { return Default(); }
+  const char *Allocation() { return Magenta(); }
+  const char *EndAllocation() { return Default(); }
+
+  const char *ShadowByte(u8 byte) {
+    switch (byte) {
+      case kAsanHeapLeftRedzoneMagic:
+      case kAsanHeapRightRedzoneMagic:
+      case kAsanArrayCookieMagic:
+        return Red();
+      case kAsanHeapFreeMagic:
+        return Magenta();
+      case kAsanStackLeftRedzoneMagic:
+      case kAsanStackMidRedzoneMagic:
+      case kAsanStackRightRedzoneMagic:
+      case kAsanStackPartialRedzoneMagic:
+        return Red();
+      case kAsanStackAfterReturnMagic:
+        return Magenta();
+      case kAsanInitializationOrderMagic:
+        return Cyan();
+      case kAsanUserPoisonedMemoryMagic:
+      case kAsanContiguousContainerOOBMagic:
+      case kAsanAllocaLeftMagic:
+      case kAsanAllocaRightMagic:
+        return Blue();
+      case kAsanStackUseAfterScopeMagic:
+        return Magenta();
+      case kAsanGlobalRedzoneMagic:
+        return Red();
+      case kAsanInternalHeapMagic:
+        return Yellow();
+      case kAsanIntraObjectRedzone:
+        return Yellow();
+      default:
+        return Default();
+    }
+  }
+  const char *EndShadowByte() { return Default(); }
+  const char *MemoryByte() { return Magenta(); }
+  const char *EndMemoryByte() { return Default(); }
+};
+
+enum ShadowKind : u8 {
+  kShadowKindLow,
+  kShadowKindGap,
+  kShadowKindHigh,
+};
+static const char *const ShadowNames[] = {"low shadow", "shadow gap",
+                                          "high shadow"};
+
+struct ShadowAddressDescription {
+  uptr addr;
+  ShadowKind kind;
+  u8 byte;
+};
+
+bool GetShadowAddressInformation(uptr addr, ShadowAddressDescription *descr);
+bool DescribeAddressIfShadow(uptr addr);
+
+enum AccessType {
+  kAccessTypeLeft,
+  kAccessTypeRight,
+  kAccessTypeInside,
+  kAccessTypeUnknown,  // This means we have an AddressSanitizer bug!
+};
+
+struct ChunkAccess {
+  uptr bad_addr;
+  sptr offset;
+  uptr chunk_begin;
+  uptr chunk_size;
+  u32 access_type : 2;
+  u32 alloc_type : 2;
+};
+
+struct HeapAddressDescription {
+  uptr addr;
+  uptr alloc_tid;
+  uptr free_tid;
+  u32 alloc_stack_id;
+  u32 free_stack_id;
+  ChunkAccess chunk_access;
+};
+
+bool GetHeapAddressInformation(uptr addr, uptr access_size,
+                               HeapAddressDescription *descr);
+bool DescribeAddressIfHeap(uptr addr, uptr access_size = 1);
+
+struct StackAddressDescription {
+  uptr addr;
+  uptr tid;
+  uptr offset;
+  uptr frame_pc;
+  const char *frame_descr;
+};
+bool GetStackAddressInformation(uptr addr, StackAddressDescription *descr);
+bool DescribeAddressIfStack(uptr addr, uptr access_size);
+
+struct GlobalAddressDescription {
+  uptr addr;
+  // Assume address is close to at most four globals.
+  static const int kMaxGlobals = 4;
+  __asan_global globals[kMaxGlobals];
+  u32 reg_sites[kMaxGlobals];
+  u8 size;
+};
+
+bool GetGlobalAddressInformation(uptr addr, GlobalAddressDescription *descr);
+bool DescribeAddressIfGlobal(uptr addr, uptr access_size, const char *bug_type);
+
+}  // namespace __asan

lib/asan/asan_descriptions.cc

+//===-- asan_descriptions.cc ------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// ASan functions for getting information about an address and/or printing it.
+//===----------------------------------------------------------------------===//
+
+#include "asan_descriptions.h"
+#include "asan_mapping.h"
+#include "asan_report.h"
+#include "asan_stack.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+
+namespace __asan {
+
+// Return " (thread_name) " or an empty string if the name is empty.
+const char *ThreadNameWithParenthesis(AsanThreadContext *t, char buff[],
+                                      uptr buff_len) {
+  const char *name = t->name;
+  if (name[0] == '\0') return "";
+  buff[0] = 0;
+  internal_strncat(buff, " (", 3);
+  internal_strncat(buff, name, buff_len - 4);
+  internal_strncat(buff, ")", 2);
+  return buff;
+}
+
+const char *ThreadNameWithParenthesis(u32 tid, char buff[], uptr buff_len) {
+  if (tid == kInvalidTid) return "";
+  asanThreadRegistry().CheckLocked();
+  AsanThreadContext *t = GetThreadContextByTidLocked(tid);
+  return ThreadNameWithParenthesis(t, buff, buff_len);
+}
+
+void DescribeThread(AsanThreadContext *context) {
+  CHECK(context);
+  asanThreadRegistry().CheckLocked();
+  // No need to announce the main thread.
+  if (context->tid == 0 || context->announced) {
+    return;
+  }
+  context->announced = true;
+  char tname[128];
+  InternalScopedString str(1024);
+  str.append("Thread T%d%s", context->tid,
+             ThreadNameWithParenthesis(context->tid, tname, sizeof(tname)));
+  if (context->parent_tid == kInvalidTid) {
+    str.append(" created by unknown thread\n");
+    Printf("%s", str.data());
+    return;
+  }
+  str.append(
+      " created by T%d%s here:\n", context->parent_tid,
+      ThreadNameWithParenthesis(context->parent_tid, tname, sizeof(tname)));
+  Printf("%s", str.data());
+  StackDepotGet(context->stack_id).Print();
+  // Recursively described parent thread if needed.
+  if (flags()->print_full_thread_history) {
+    AsanThreadContext *parent_context =
+        GetThreadContextByTidLocked(context->parent_tid);
+    DescribeThread(parent_context);
+  }
+}
+
+// Shadow descriptions
+static bool GetShadowKind(uptr addr, ShadowKind *shadow_kind) {
+  CHECK(!AddrIsInMem(addr));
+  if (AddrIsInShadowGap(addr)) {
+    *shadow_kind = kShadowKindGap;
+  } else if (AddrIsInHighShadow(addr)) {
+    *shadow_kind = kShadowKindHigh;
+  } else if (AddrIsInLowShadow(addr)) {
+    *shadow_kind = kShadowKindLow;
+  } else {
+    CHECK(0 && "Address is not in memory and not in shadow?");
+    return false;
+  }
+  return true;
+}
+
+bool DescribeAddressIfShadow(uptr addr) {
+  ShadowAddressDescription descr;
+  if (!GetShadowAddressInformation(addr, &descr)) return false;
+  Printf("Address %p is located in the %s area.\n", addr,
+         ShadowNames[descr.kind]);
+  return true;
+}
+
+bool GetShadowAddressInformation(uptr addr, ShadowAddressDescription *descr) {
+  if (AddrIsInMem(addr)) return false;
+  ShadowKind shadow_kind;
+  if (!GetShadowKind(addr, &shadow_kind)) return false;
+  if (shadow_kind != kShadowKindGap) descr->byte = *(u8 *)addr;
+  descr->addr = addr;
+  descr->kind = shadow_kind;
+  return true;
+}
+
+// Heap descriptions
+static void GetAccessToHeapChunkInformation(ChunkAccess *descr,
+                                            AsanChunkView chunk, uptr addr,
+                                            uptr access_size) {
+  descr->bad_addr = addr;
+  if (chunk.AddrIsAtLeft(addr, access_size, &descr->offset)) {
+    descr->access_type = kAccessTypeLeft;
+  } else if (chunk.AddrIsAtRight(addr, access_size, &descr->offset)) {
+    descr->access_type = kAccessTypeRight;
+    if (descr->offset < 0) {
+      descr->bad_addr -= descr->offset;
+      descr->offset = 0;
+    }
+  } else if (chunk.AddrIsInside(addr, access_size, &descr->offset)) {
+    descr->access_type = kAccessTypeInside;
+  } else {
+    descr->access_type = kAccessTypeUnknown;
+  }
+  descr->chunk_begin = chunk.Beg();
+  descr->chunk_size = chunk.UsedSize();
+  descr->alloc_type = chunk.AllocType();
+}
+
+static void PrintHeapChunkAccess(uptr addr, const ChunkAccess &descr) {
+  Decorator d;
+  InternalScopedString str(4096);
+  str.append("%s", d.Location());
+  switch (descr.access_type) {
+    case kAccessTypeLeft:
+      str.append("%p is located %zd bytes to the left of",
+                 (void *)descr.bad_addr, descr.offset);
+      break;
+    case kAccessTypeRight:
+      str.append("%p is located %zd bytes to the right of",
+                 (void *)descr.bad_addr, descr.offset);
+      break;
+    case kAccessTypeInside:
+      str.append("%p is located %zd bytes inside of", (void *)descr.bad_addr,
+                 descr.offset);
+      break;
+    case kAccessTypeUnknown:
+      str.append(
+          "%p is located somewhere around (this is AddressSanitizer bug!)",
+          (void *)descr.bad_addr);
+  }
+  str.append(" %zu-byte region [%p,%p)\n", descr.chunk_size,
+             (void *)descr.chunk_begin,
+             (void *)(descr.chunk_begin + descr.chunk_size));
+  str.append("%s", d.EndLocation());
+  Printf("%s", str.data());
+}
+
+bool GetHeapAddressInformation(uptr addr, uptr access_size,
+                               HeapAddressDescription *descr) {
+  AsanChunkView chunk = FindHeapChunkByAddress(addr);
+  if (!chunk.IsValid()) {
+    return false;
+  }
+  descr->addr = addr;
+  GetAccessToHeapChunkInformation(&descr->chunk_access, chunk, addr,
+                                  access_size);
+  CHECK_NE(chunk.AllocTid(), kInvalidTid);
+  descr->alloc_tid = chunk.AllocTid();
+  descr->alloc_stack_id = chunk.GetAllocStackId();
+  descr->free_tid = chunk.FreeTid();
+  if (descr->free_tid != kInvalidTid)
+    descr->free_stack_id = chunk.GetFreeStackId();
+  return true;
+}
+
+static StackTrace GetStackTraceFromId(u32 id) {
+  CHECK(id);
+  StackTrace res = StackDepotGet(id);
+  CHECK(res.trace);
+  return res;
+}
+
+bool DescribeAddressIfHeap(uptr addr, uptr access_size) {
+  HeapAddressDescription descr;
+  if (!GetHeapAddressInformation(addr, access_size, &descr)) {
+    Printf(
+        "AddressSanitizer can not describe address in more detail "
+        "(wild memory access suspected).\n");
+    return false;
+  }
+  PrintHeapChunkAccess(addr, descr.chunk_access);
+
+  asanThreadRegistry().CheckLocked();
+  AsanThreadContext *alloc_thread =
+      GetThreadContextByTidLocked(descr.alloc_tid);
+  StackTrace alloc_stack = GetStackTraceFromId(descr.alloc_stack_id);
+
+  char tname[128];
+  Decorator d;
+  AsanThreadContext *free_thread = nullptr;
+  if (descr.free_tid != kInvalidTid) {
+    free_thread = GetThreadContextByTidLocked(descr.free_tid);
+    Printf("%sfreed by thread T%d%s here:%s\n", d.Allocation(),
+           free_thread->tid,
+           ThreadNameWithParenthesis(free_thread, tname, sizeof(tname)),
+           d.EndAllocation());
+    StackTrace free_stack = GetStackTraceFromId(descr.free_stack_id);
+    free_stack.Print();
+    Printf("%spreviously allocated by thread T%d%s here:%s\n", d.Allocation(),
+           alloc_thread->tid,
+           ThreadNameWithParenthesis(alloc_thread, tname, sizeof(tname)),
+           d.EndAllocation());
+  } else {
+    Printf("%sallocated by thread T%d%s here:%s\n", d.Allocation(),
+           alloc_thread->tid,
+           ThreadNameWithParenthesis(alloc_thread, tname, sizeof(tname)),
+           d.EndAllocation());
+  }
+  alloc_stack.Print();
+  DescribeThread(GetCurrentThread());
+  if (free_thread) DescribeThread(free_thread);
+  DescribeThread(alloc_thread);
+  return true;
+}
+
+// Stack descriptions
+bool GetStackAddressInformation(uptr addr, StackAddressDescription *descr) {
+  AsanThread *t = FindThreadByStackAddress(addr);
+  if (!t) return false;
+
+  descr->addr = addr;
+  descr->tid = t->tid();
+  // Try to fetch precise stack frame for this access.
+  AsanThread::StackFrameAccess access;
+  if (!t->GetStackFrameAccessByAddr(addr, &access)) {
+    descr->frame_descr = nullptr;
+    return true;
+  }
+
+  descr->offset = access.offset;
+  descr->frame_pc = access.frame_pc;
+  descr->frame_descr = access.frame_descr;
+
+#if SANITIZER_PPC64V1
+  // 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.
+  descr->frame_pc = *reinterpret_cast<uptr *>(descr->frame_pc);
+#endif
+  descr->frame_pc += 16;
+
+  return true;
+}
+
+static void PrintAccessAndVarIntersection(const StackVarDescr &var, uptr addr,
+                                          uptr access_size, uptr prev_var_end,
+                                          uptr next_var_beg) {
+  uptr var_end = var.beg + var.size;
+  uptr addr_end = addr + access_size;
+  const char *pos_descr = nullptr;
+  // If the variable [var.beg, var_end) is the nearest variable to the
+  // current memory access, indicate it in the log.
+  if (addr >= var.beg) {
+    if (addr_end <= var_end)
+      pos_descr = "is inside";  // May happen if this is a use-after-return.
+    else if (addr < var_end)
+      pos_descr = "partially overflows";
+    else if (addr_end <= next_var_beg &&
+             next_var_beg - addr_end >= addr - var_end)
+      pos_descr = "overflows";
+  } else {
+    if (addr_end > var.beg)
+      pos_descr = "partially underflows";
+    else if (addr >= prev_var_end && addr - prev_var_end >= var.beg - addr_end)
+      pos_descr = "underflows";
+  }
+  InternalScopedString str(1024);
+  str.append("    [%zd, %zd)", var.beg, var_end);
+  // Render variable name.
+  str.append(" '");
+  for (uptr i = 0; i < var.name_len; ++i) {
+    str.append("%c", var.name_pos[i]);
+  }
+  str.append("'");
+  if (pos_descr) {
+    Decorator d;
+    // FIXME: we may want to also print the size of the access here,
+    // but in case of accesses generated by memset it may be confusing.
+    str.append("%s <== Memory access at offset %zd %s this variable%s\n",
+               d.Location(), addr, pos_descr, d.EndLocation());
+  } else {
+    str.append("\n");
+  }
+  Printf("%s", str.data());
+}
+
+bool DescribeAddressIfStack(uptr addr, uptr access_size) {
+  StackAddressDescription descr;
+  if (!GetStackAddressInformation(addr, &descr)) return false;
+
+  Decorator d;
+  char tname[128];
+  Printf("%s", d.Location());
+  Printf("Address %p is located in stack of thread T%d%s", addr, descr.tid,
+         ThreadNameWithParenthesis(descr.tid, tname, sizeof(tname)));
+
+  if (!descr.frame_descr) {
+    Printf("%s\n", d.EndLocation());
+    return true;
+  }
+  Printf(" at offset %zu in frame%s\n", descr.offset, d.EndLocation());
+
+  // Now we print the frame where the alloca has happened.
+  // We print this frame as a stack trace with one element.
+  // The symbolizer may print more than one frame if inlining was involved.
+  // The frame numbers may be different than those in the stack trace printed
+  // 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).
+  Printf("%s", d.EndLocation());
+  StackTrace alloca_stack(&descr.frame_pc, 1);
+  alloca_stack.Print();
+
+  InternalMmapVector<StackVarDescr> vars(16);
+  if (!ParseFrameDescription(descr.frame_descr, &vars)) {
+    Printf(
+        "AddressSanitizer can't parse the stack frame "
+        "descriptor: |%s|\n",
+        descr.frame_descr);
+    // 'addr' is a stack address, so return true even if we can't parse frame
+    return true;
+  }
+  uptr n_objects = vars.size();
+  // Report the number of stack objects.
+  Printf("  This frame has %zu object(s):\n", n_objects);
+
+  // Report all objects in this frame.
+  for (uptr i = 0; i < n_objects; i++) {
+    uptr prev_var_end = i ? vars[i - 1].beg + vars[i - 1].size : 0;
+    uptr next_var_beg = i + 1 < n_objects ? vars[i + 1].beg : ~(0UL);
+    PrintAccessAndVarIntersection(vars[i], descr.offset, access_size,
+                                  prev_var_end, next_var_beg);
+  }
+  Printf(
+      "HINT: this may be a false positive if your program uses "
+      "some custom stack unwind mechanism or swapcontext\n");
+  if (SANITIZER_WINDOWS)
+    Printf("      (longjmp, SEH and C++ exceptions *are* supported)\n");
+  else
+    Printf("      (longjmp and C++ exceptions *are* supported)\n");
+
+  DescribeThread(GetThreadContextByTidLocked(descr.tid));
+  return true;
+}
+
+// Global descriptions
+static void DescribeAddressRelativeToGlobal(uptr addr, uptr access_size,
+                                            const __asan_global &g) {
+  InternalScopedString str(4096);
+  Decorator d;
+  str.append("%s", d.Location());
+  if (addr < g.beg) {
+    str.append("%p is located %zd bytes to the left", (void *)addr,
+               g.beg - addr);
+  } else if (addr + access_size > g.beg + g.size) {
+    if (addr < g.beg + g.size) addr = g.beg + g.size;
+    str.append("%p is located %zd bytes to the right", (void *)addr,
+               addr - (g.beg + g.size));
+  } else {
+    // Can it happen?
+    str.append("%p is located %zd bytes inside", (void *)addr, addr - g.beg);
+  }
+  str.append(" of global variable '%s' defined in '",
+             MaybeDemangleGlobalName(g.name));
+  PrintGlobalLocation(&str, g);
+  str.append("' (0x%zx) of size %zu\n", g.beg, g.size);
+  str.append("%s", d.EndLocation());
+  PrintGlobalNameIfASCII(&str, g);
+  Printf("%s", str.data());
+}
+
+bool GetGlobalAddressInformation(uptr addr, GlobalAddressDescription *descr) {
+  descr->addr = addr;
+  int globals_num = GetGlobalsForAddress(addr, descr->globals, descr->reg_sites,
+                                         ARRAY_SIZE(descr->globals));
+  descr->size = globals_num;
+  return globals_num != 0;
+}
+
+bool DescribeAddressIfGlobal(uptr addr, uptr access_size,
+                             const char *bug_type) {
+  GlobalAddressDescription descr;
+  if (!GetGlobalAddressInformation(addr, &descr)) return false;
+
+  for (int i = 0; i < descr.size; i++) {
+    DescribeAddressRelativeToGlobal(descr.addr, access_size, descr.globals[i]);
+    if (0 == internal_strcmp(bug_type, "initialization-order-fiasco") &&
+        descr.reg_sites[i]) {
+      Printf("  registered at:\n");
+      StackDepotGet(descr.reg_sites[i]).Print();
+    }
+  }
+  return true;
+}
+
+}  // namespace __asan

lib/asan/asan_globals.cc

 #include "asan_stack.h"
 #include "asan_stats.h"
 #include "asan_suppressions.h"
 #include "asan_thread.h"
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_mutex.h"
 #include "sanitizer_common/sanitizer_placement_new.h"
 #include "sanitizer_common/sanitizer_stackdepot.h"
+#include "sanitizer_common/sanitizer_symbolizer.h"
 
 namespace __asan {
 
 typedef __asan_global Global;
 
 struct ListOfGlobals {
   const Global *g;
   ListOfGlobals *next;
if (IsAddressNearGlobal(addr, g)) {
         reg_sites[res] = FindRegistrationSite(&g);
       res++;
       if (res == max_globals) break;
     }
   }
   return res;
 }
 
-bool GetInfoForAddressIfGlobal(uptr addr, AddressDescription *descr) {
-  Global g = {};
-  if (GetGlobalsForAddress(addr, &g, nullptr, 1)) {
-    internal_strncpy(descr->name, g.name, descr->name_size);
-    descr->region_address = g.beg;
-    descr->region_size = g.size;
-    descr->region_kind = "global";
-    return true;
-  }
-  return false;
-}
-
 enum GlobalSymbolState {
   UNREGISTERED = 0,
   REGISTERED = 1
 };
 
 // Check ODR violation for given global G via special ODR indicator. We use
 // this method in case compiler instruments global variables through their
 // local aliases.
for (uptr i = 0, n = dynamic_init_globals->size(); i < n; ++i) {
     const Global *g = &dyn_g.g;
     // Unpoison the whole global.
     PoisonShadowForGlobal(g, 0);
     // Poison redzones back.
     PoisonRedZones(*g);
   }
 }
 
+static bool IsASCII(unsigned char c) { return /*0x00 <= c &&*/ c <= 0x7F; }
+
+const char *MaybeDemangleGlobalName(const char *name) {
+  // We can spoil names of globals with C linkage, so use an heuristic
+  // approach to check if the name should be demangled.
+  bool should_demangle = false;
+  if (name[0] == '_' && name[1] == 'Z')
+    should_demangle = true;
+  else if (SANITIZER_WINDOWS && name[0] == '\01' && name[1] == '?')
+    should_demangle = true;
+
+  return should_demangle ? Symbolizer::GetOrInit()->Demangle(name) : name;
+}
+
+// Check if the global is a zero-terminated ASCII string. If so, print it.
+void PrintGlobalNameIfASCII(InternalScopedString *str, const __asan_global &g) {
+  for (uptr p = g.beg; p < g.beg + g.size - 1; p++) {
+    unsigned char c = *(unsigned char *)p;
+    if (c == '\0' || !IsASCII(c)) return;
+  }
+  if (*(char *)(g.beg + g.size - 1) != '\0') return;
+  str->append("  '%s' is ascii string '%s'\n", MaybeDemangleGlobalName(g.name),
+              (char *)g.beg);
+}
+
+static const char *GlobalFilename(const __asan_global &g) {
+  const char *res = g.module_name;
+  // Prefer the filename from source location, if is available.
+  if (g.location) res = g.location->filename;
+  CHECK(res);
+  return res;
+}
+
+void PrintGlobalLocation(InternalScopedString *str, const __asan_global &g) {
+  str->append("%s", GlobalFilename(g));
+  if (!g.location) return;
+  if (g.location->line_no) str->append(":%d", g.location->line_no);
+  if (g.location->column_no) str->append(":%d", g.location->column_no);
+}
+
 } // namespace __asan
 
 // ---------------------- Interface ---------------- {{{1
 using namespace __asan;  // NOLINT
 
 
 // Apply __asan_register_globals to all globals found in the same loaded
 // executable or shared library as `flag'. The flag tracks whether globals have

lib/asan/asan_report.h

struct AddressDescription {
   uptr region_size;
   const char *region_kind;
 };
 
 // Returns the number of globals close to the provided address and copies
 // them to "globals" array.
 int GetGlobalsForAddress(uptr addr, __asan_global *globals, u32 *reg_sites,
                          int max_globals);
+
 bool GetInfoForAddressIfGlobal(uptr addr, AddressDescription *descr);
+const char *MaybeDemangleGlobalName(const char *name);
+void PrintGlobalNameIfASCII(InternalScopedString *str, const __asan_global &g);
+void PrintGlobalLocation(InternalScopedString *str, const __asan_global &g);
+
 // The following functions prints address description depending
 // on the memory type (shadow/heap/stack/global).
-void DescribeHeapAddress(uptr addr, uptr access_size);
-bool DescribeAddressIfShadow(uptr addr, AddressDescription *descr = nullptr,
-                             bool print = true);
 bool ParseFrameDescription(const char *frame_descr,
                            InternalMmapVector<StackVarDescr> *vars);
-bool DescribeAddressIfStack(uptr addr, uptr access_size);
-void DescribeThread(AsanThreadContext *context);
 
 // Different kinds of error reports.
 void ReportGenericError(uptr pc, uptr bp, uptr sp, uptr addr, bool is_write,
                         uptr access_size, u32 exp, bool fatal);
 void ReportStackOverflow(const SignalContext &sig);
 void ReportDeadlySignal(const char *description, const SignalContext &sig);
 void ReportNewDeleteSizeMismatch(uptr addr, uptr alloc_size, uptr delete_size,
                                  BufferedStackTrace *free_stack);

lib/asan/asan_report.cc

 //===-- asan_report.cc ----------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of AddressSanitizer, an address sanity checker.
 //
 // This file contains error reporting code.
 //===----------------------------------------------------------------------===//
 
 #include "asan_flags.h"
+#include "asan_descriptions.h"
 #include "asan_internal.h"
 #include "asan_mapping.h"
 #include "asan_report.h"
 #include "asan_scariness_score.h"
 #include "asan_stack.h"
 #include "asan_thread.h"
 #include "sanitizer_common/sanitizer_common.h"
 #include "sanitizer_common/sanitizer_flags.h"
void AppendToErrorMessageBuffer(const char *buffer) {
   uptr remaining = kErrorMessageBufferSize - error_message_buffer_pos;
   internal_strncpy(error_message_buffer + error_message_buffer_pos,
                    buffer, remaining);
   error_message_buffer[kErrorMessageBufferSize - 1] = '\0';
   // FIXME: reallocate the buffer instead of truncating the message.
   error_message_buffer_pos += Min(remaining, length);
 }
 
-// ---------------------- Decorator ------------------------------ {{{1
-class Decorator: public __sanitizer::SanitizerCommonDecorator {
- public:
-  Decorator() : SanitizerCommonDecorator() { }
-  const char *Access()     { return Blue(); }
-  const char *EndAccess()  { return Default(); }
-  const char *Location()   { return Green(); }
-  const char *EndLocation() { return Default(); }
-  const char *Allocation()  { return Magenta(); }
-  const char *EndAllocation()  { return Default(); }
-
-  const char *ShadowByte(u8 byte) {
-    switch (byte) {
-      case kAsanHeapLeftRedzoneMagic:
-      case kAsanHeapRightRedzoneMagic:
-      case kAsanArrayCookieMagic:
-        return Red();
-      case kAsanHeapFreeMagic:
-        return Magenta();
-      case kAsanStackLeftRedzoneMagic:
-      case kAsanStackMidRedzoneMagic:
-      case kAsanStackRightRedzoneMagic:
-      case kAsanStackPartialRedzoneMagic:
-        return Red();
-      case kAsanStackAfterReturnMagic:
-        return Magenta();
-      case kAsanInitializationOrderMagic:
-        return Cyan();
-      case kAsanUserPoisonedMemoryMagic:
-      case kAsanContiguousContainerOOBMagic:
-      case kAsanAllocaLeftMagic:
-      case kAsanAllocaRightMagic:
-        return Blue();
-      case kAsanStackUseAfterScopeMagic:
-        return Magenta();
-      case kAsanGlobalRedzoneMagic:
-        return Red();
-      case kAsanInternalHeapMagic:
-        return Yellow();
-      case kAsanIntraObjectRedzone:
-        return Yellow();
-      default:
-        return Default();
-    }
-  }
-  const char *EndShadowByte() { return Default(); }
-  const char *MemoryByte() { return Magenta(); }
-  const char *EndMemoryByte() { return Default(); }
-};
-
 // ---------------------- Helper functions ----------------------- {{{1
 
 static void PrintMemoryByte(InternalScopedString *str, const char *before,
     u8 byte, bool in_shadow, const char *after = "\n") {
   Decorator d;
   str->append("%s%s%x%x%s%s", before,
               in_shadow ? d.ShadowByte(byte) : d.MemoryByte(),
               byte >> 4, byte & 15,
if (zone_name) {
       Printf("malloc_zone_from_ptr(%p) = %p, which doesn't have a name\n",
                  ptr, zone_ptr);
     }
   } else {
     Printf("malloc_zone_from_ptr(%p) = 0\n", ptr);
   }
 }
 
-static void DescribeThread(AsanThread *t) {
-  if (t)
-    DescribeThread(t->context());
-}
-
 // ---------------------- Address Descriptions ------------------- {{{1
 
-static bool IsASCII(unsigned char c) {
-  return /*0x00 <= c &&*/ c <= 0x7F;
-}
-
-static const char *MaybeDemangleGlobalName(const char *name) {
-  // We can spoil names of globals with C linkage, so use an heuristic
-  // approach to check if the name should be demangled.
-  bool should_demangle = false;
-  if (name[0] == '_' && name[1] == 'Z')
-    should_demangle = true;
-  else if (SANITIZER_WINDOWS && name[0] == '\01' && name[1] == '?')
-    should_demangle = true;
-
-  return should_demangle ? Symbolizer::GetOrInit()->Demangle(name) : name;
-}
-
-// Check if the global is a zero-terminated ASCII string. If so, print it.
-static void PrintGlobalNameIfASCII(InternalScopedString *str,
-                                   const __asan_global &g) {
-  for (uptr p = g.beg; p < g.beg + g.size - 1; p++) {
-    unsigned char c = *(unsigned char*)p;
-    if (c == '\0' || !IsASCII(c)) return;
-  }
-  if (*(char*)(g.beg + g.size - 1) != '\0') return;
-  str->append("  '%s' is ascii string '%s'\n", MaybeDemangleGlobalName(g.name),
-              (char *)g.beg);
-}
-
-static const char *GlobalFilename(const __asan_global &g) {
-  const char *res = g.module_name;
-  // Prefer the filename from source location, if is available.
-  if (g.location)
-    res = g.location->filename;
-  CHECK(res);
-  return res;
-}
-
-static void PrintGlobalLocation(InternalScopedString *str,
-                                const __asan_global &g) {
-  str->append("%s", GlobalFilename(g));
-  if (!g.location)
-    return;
-  if (g.location->line_no)
-    str->append(":%d", g.location->line_no);
-  if (g.location->column_no)
-    str->append(":%d", g.location->column_no);
-}
-
-static void DescribeAddressRelativeToGlobal(uptr addr, uptr size,
-                                            const __asan_global &g) {
-  InternalScopedString str(4096);
-  Decorator d;
-  str.append("%s", d.Location());
-  if (addr < g.beg) {
-    str.append("%p is located %zd bytes to the left", (void *)addr,
-               g.beg - addr);
-  } else if (addr + size > g.beg + g.size) {
-    if (addr < g.beg + g.size)
-      addr = g.beg + g.size;
-    str.append("%p is located %zd bytes to the right", (void *)addr,
-               addr - (g.beg + g.size));
-  } else {
-    // Can it happen?
-    str.append("%p is located %zd bytes inside", (void *)addr, addr - g.beg);
-  }
-  str.append(" of global variable '%s' defined in '",
-             MaybeDemangleGlobalName(g.name));
-  PrintGlobalLocation(&str, g);
-  str.append("' (0x%zx) of size %zu\n", g.beg, g.size);
-  str.append("%s", d.EndLocation());
-  PrintGlobalNameIfASCII(&str, g);
-  Printf("%s", str.data());
-}
-
-static bool DescribeAddressIfGlobal(uptr addr, uptr size,
-                                    const char *bug_type) {
-  // Assume address is close to at most four globals.
-  const int kMaxGlobalsInReport = 4;
-  __asan_global globals[kMaxGlobalsInReport];
-  u32 reg_sites[kMaxGlobalsInReport];
-  int globals_num =
-      GetGlobalsForAddress(addr, globals, reg_sites, ARRAY_SIZE(globals));
-  if (globals_num == 0)
-    return false;
-  for (int i = 0; i < globals_num; i++) {
-    DescribeAddressRelativeToGlobal(addr, size, globals[i]);
-    if (0 == internal_strcmp(bug_type, "initialization-order-fiasco") &&
-        reg_sites[i]) {
-      Printf("  registered at:\n");
-      StackDepotGet(reg_sites[i]).Print();
-    }
-  }
-  return true;
-}
-
-bool DescribeAddressIfShadow(uptr addr, AddressDescription *descr, bool print) {
-  if (AddrIsInMem(addr))
-    return false;
-  const char *area_type = nullptr;
-  if (AddrIsInShadowGap(addr)) area_type = "shadow gap";
-  else if (AddrIsInHighShadow(addr)) area_type = "high shadow";
-  else if (AddrIsInLowShadow(addr)) area_type = "low shadow";
-  if (area_type != nullptr) {
-    if (print) {
-      Printf("Address %p is located in the %s area.\n", addr, area_type);
-    } else {
-      CHECK(descr);
-      descr->region_kind = area_type;
-    }
-    return true;
-  }
-  CHECK(0 && "Address is not in memory and not in shadow?");
-  return false;
-}
-
-// Return " (thread_name) " or an empty string if the name is empty.
-const char *ThreadNameWithParenthesis(AsanThreadContext *t, char buff[],
-                                      uptr buff_len) {
-  const char *name = t->name;
-  if (name[0] == '\0') return "";
-  buff[0] = 0;
-  internal_strncat(buff, " (", 3);
-  internal_strncat(buff, name, buff_len - 4);
-  internal_strncat(buff, ")", 2);
-  return buff;
-}
-
-const char *ThreadNameWithParenthesis(u32 tid, char buff[],
-                                      uptr buff_len) {
-  if (tid == kInvalidTid) return "";
-  asanThreadRegistry().CheckLocked();
-  AsanThreadContext *t = GetThreadContextByTidLocked(tid);
-  return ThreadNameWithParenthesis(t, buff, buff_len);
-}
-
-static void PrintAccessAndVarIntersection(const StackVarDescr &var, uptr addr,
-                                          uptr access_size, uptr prev_var_end,
-                                          uptr next_var_beg) {
-  uptr var_end = var.beg + var.size;
-  uptr addr_end = addr + access_size;
-  const char *pos_descr = nullptr;
-  // If the variable [var.beg, var_end) is the nearest variable to the
-  // current memory access, indicate it in the log.
-  if (addr >= var.beg) {
-    if (addr_end <= var_end)
-      pos_descr = "is inside";  // May happen if this is a use-after-return.
-    else if (addr < var_end)
-      pos_descr = "partially overflows";
-    else if (addr_end <= next_var_beg &&
-             next_var_beg - addr_end >= addr - var_end)
-      pos_descr = "overflows";
-  } else {
-    if (addr_end > var.beg)
-      pos_descr = "partially underflows";
-    else if (addr >= prev_var_end &&
-             addr - prev_var_end >= var.beg - addr_end)
-      pos_descr = "underflows";
-  }
-  InternalScopedString str(1024);
-  str.append("    [%zd, %zd)", var.beg, var_end);
-  // Render variable name.
-  str.append(" '");
-  for (uptr i = 0; i < var.name_len; ++i) {
-    str.append("%c", var.name_pos[i]);
-  }
-  str.append("'");
-  if (pos_descr) {
-    Decorator d;
-    // FIXME: we may want to also print the size of the access here,
-    // but in case of accesses generated by memset it may be confusing.
-    str.append("%s <== Memory access at offset %zd %s this variable%s\n",
-               d.Location(), addr, pos_descr, d.EndLocation());
-  } else {
-    str.append("\n");
-  }
-  Printf("%s", str.data());
-}
-
 bool ParseFrameDescription(const char *frame_descr,
                            InternalMmapVector<StackVarDescr> *vars) {
   CHECK(frame_descr);
   char *p;
   // This string is created by the compiler and has the following form:
   // "n alloc_1 alloc_2 ... alloc_n"
   // where alloc_i looks like "offset size len ObjectName".
   uptr n_objects = (uptr)internal_simple_strtoll(frame_descr, &p, 10);
for (uptr i = 0; i < n_objects; i++) {
     StackVarDescr var = {beg, size, p, len};
     vars->push_back(var);
     p += len;
   }
 
   return true;
 }
 
-bool DescribeAddressIfStack(uptr addr, uptr access_size) {
-  AsanThread *t = FindThreadByStackAddress(addr);
-  if (!t) return false;
-
-  Decorator d;
-  char tname[128];
-  Printf("%s", d.Location());
-  Printf("Address %p is located in stack of thread T%d%s", addr, t->tid(),
-         ThreadNameWithParenthesis(t->tid(), tname, sizeof(tname)));
-
-  // Try to fetch precise stack frame for this access.
-  AsanThread::StackFrameAccess access;
-  if (!t->GetStackFrameAccessByAddr(addr, &access)) {
-    Printf("%s\n", d.EndLocation());
-    return true;
-  }
-  Printf(" at offset %zu in frame%s\n", access.offset, d.EndLocation());
-
-  // Now we print the frame where the alloca has happened.
-  // We print this frame as a stack trace with one element.
-  // The symbolizer may print more than one frame if inlining was involved.
-  // The frame numbers may be different than those in the stack trace printed
-  // 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).
-#if SANITIZER_PPC64V1
-  // 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
-  access.frame_pc += 16;
-  Printf("%s", d.EndLocation());
-  StackTrace alloca_stack(&access.frame_pc, 1);
-  alloca_stack.Print();
-
-  InternalMmapVector<StackVarDescr> vars(16);
-  if (!ParseFrameDescription(access.frame_descr, &vars)) {
-    Printf("AddressSanitizer can't parse the stack frame "
-           "descriptor: |%s|\n", access.frame_descr);
-    // 'addr' is a stack address, so return true even if we can't parse frame
-    return true;
-  }
-  uptr n_objects = vars.size();
-  // Report the number of stack objects.
-  Printf("  This frame has %zu object(s):\n", n_objects);
-
-  // Report all objects in this frame.
-  for (uptr i = 0; i < n_objects; i++) {
-    uptr prev_var_end = i ? vars[i - 1].beg + vars[i - 1].size : 0;
-    uptr next_var_beg = i + 1 < n_objects ? vars[i + 1].beg : ~(0UL);
-    PrintAccessAndVarIntersection(vars[i], access.offset, access_size,
-                                  prev_var_end, next_var_beg);
-  }
-  Printf("HINT: this may be a false positive if your program uses "
-         "some custom stack unwind mechanism or swapcontext\n");
-  if (SANITIZER_WINDOWS)
-    Printf("      (longjmp, SEH and C++ exceptions *are* supported)\n");
-  else
-    Printf("      (longjmp and C++ exceptions *are* supported)\n");
-
-  DescribeThread(t);
-  return true;
-}
-
-static void DescribeAccessToHeapChunk(AsanChunkView chunk, uptr addr,
-                                      uptr access_size) {
-  sptr offset;
-  Decorator d;
-  InternalScopedString str(4096);
-  str.append("%s", d.Location());
-  if (chunk.AddrIsAtLeft(addr, access_size, &offset)) {
-    str.append("%p is located %zd bytes to the left of", (void *)addr, offset);
-  } else if (chunk.AddrIsAtRight(addr, access_size, &offset)) {
-    if (offset < 0) {
-      addr -= offset;
-      offset = 0;
-    }
-    str.append("%p is located %zd bytes to the right of", (void *)addr, offset);
-  } else if (chunk.AddrIsInside(addr, access_size, &offset)) {
-    str.append("%p is located %zd bytes inside of", (void*)addr, offset);
-  } else {
-    str.append("%p is located somewhere around (this is AddressSanitizer bug!)",
-               (void *)addr);
-  }
-  str.append(" %zu-byte region [%p,%p)\n", chunk.UsedSize(),
-             (void *)(chunk.Beg()), (void *)(chunk.End()));
-  str.append("%s", d.EndLocation());
-  Printf("%s", str.data());
-}
-
-void DescribeHeapAddress(uptr addr, uptr access_size) {
-  AsanChunkView chunk = FindHeapChunkByAddress(addr);
-  if (!chunk.IsValid()) {
-    Printf("AddressSanitizer can not describe address in more detail "
-           "(wild memory access suspected).\n");
-    return;
-  }
-  DescribeAccessToHeapChunk(chunk, addr, access_size);
-  CHECK_NE(chunk.AllocTid(), kInvalidTid);
-  asanThreadRegistry().CheckLocked();
-  AsanThreadContext *alloc_thread =
-      GetThreadContextByTidLocked(chunk.AllocTid());
-  StackTrace alloc_stack = chunk.GetAllocStack();
-  char tname[128];
-  Decorator d;
-  AsanThreadContext *free_thread = nullptr;
-  if (chunk.FreeTid() != kInvalidTid) {
-    free_thread = GetThreadContextByTidLocked(chunk.FreeTid());
-    Printf("%sfreed by thread T%d%s here:%s\n", d.Allocation(),
-           free_thread->tid,
-           ThreadNameWithParenthesis(free_thread, tname, sizeof(tname)),
-           d.EndAllocation());
-    StackTrace free_stack = chunk.GetFreeStack();
-    free_stack.Print();
-    Printf("%spreviously allocated by thread T%d%s here:%s\n",
-           d.Allocation(), alloc_thread->tid,
-           ThreadNameWithParenthesis(alloc_thread, tname, sizeof(tname)),
-           d.EndAllocation());
-  } else {
-    Printf("%sallocated by thread T%d%s here:%s\n", d.Allocation(),
-           alloc_thread->tid,
-           ThreadNameWithParenthesis(alloc_thread, tname, sizeof(tname)),
-           d.EndAllocation());
-  }
-  alloc_stack.Print();
-  DescribeThread(GetCurrentThread());
-  if (free_thread)
-    DescribeThread(free_thread);
-  DescribeThread(alloc_thread);
-}
-
 static void DescribeAddress(uptr addr, uptr access_size, const char *bug_type) {
   // Check if this is shadow or shadow gap.
   if (DescribeAddressIfShadow(addr))
     return;
   CHECK(AddrIsInMem(addr));
   if (DescribeAddressIfGlobal(addr, access_size, bug_type))
     return;
   if (DescribeAddressIfStack(addr, access_size))
     return;
   // Assume it is a heap address.
-  DescribeHeapAddress(addr, access_size);
-}
-
-// ------------------- Thread description -------------------- {{{1
-
-void DescribeThread(AsanThreadContext *context) {
-  CHECK(context);
-  asanThreadRegistry().CheckLocked();
-  // No need to announce the main thread.
-  if (context->tid == 0 || context->announced) {
-    return;
-  }
-  context->announced = true;
-  char tname[128];
-  InternalScopedString str(1024);
-  str.append("Thread T%d%s", context->tid,
-             ThreadNameWithParenthesis(context->tid, tname, sizeof(tname)));
-  if (context->parent_tid == kInvalidTid) {
-    str.append(" created by unknown thread\n");
-    Printf("%s", str.data());
-    return;
-  }
-  str.append(
-      " created by T%d%s here:\n", context->parent_tid,
-      ThreadNameWithParenthesis(context->parent_tid, tname, sizeof(tname)));
-  Printf("%s", str.data());
-  StackDepotGet(context->stack_id).Print();
-  // Recursively described parent thread if needed.
-  if (flags()->print_full_thread_history) {
-    AsanThreadContext *parent_context =
-        GetThreadContextByTidLocked(context->parent_tid);
-    DescribeThread(parent_context);
-  }
+  DescribeAddressIfHeap(addr, access_size);
 }
 
 // -------------------- Different kinds of reports ----------------- {{{1
 
 // Use ScopedInErrorReport to run common actions just before and
 // immediately after printing error report.
 class ScopedInErrorReport {
  public:
Report("ERROR: AddressSanitizer: attempting double-free on %p in "
          "thread T%d%s:\n",
          addr, curr_tid,
          ThreadNameWithParenthesis(curr_tid, tname, sizeof(tname)));
   Printf("%s", d.EndWarning());
   CHECK_GT(free_stack->size, 0);
   ScarinessScore::PrintSimple(42, "double-free");
   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
   stack.Print();
-  DescribeHeapAddress(addr, 1);
+  DescribeAddressIfHeap(addr);
   ReportErrorSummary("double-free", &stack);
 }
 
 void ReportNewDeleteSizeMismatch(uptr addr, uptr alloc_size, uptr delete_size,
                                  BufferedStackTrace *free_stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
   char tname[128];
   u32 curr_tid = GetCurrentTidOrInvalid();
   Report("ERROR: AddressSanitizer: new-delete-type-mismatch on %p in "
          "thread T%d%s:\n",
          addr, curr_tid,
          ThreadNameWithParenthesis(curr_tid, tname, sizeof(tname)));
   Printf("%s  object passed to delete has wrong type:\n", d.EndWarning());
   Printf("  size of the allocated type:   %zd bytes;\n"
          "  size of the deallocated type: %zd bytes.\n",
          alloc_size, delete_size);
   CHECK_GT(free_stack->size, 0);
   ScarinessScore::PrintSimple(10, "new-delete-type-mismatch");
   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
   stack.Print();
-  DescribeHeapAddress(addr, 1);
+  DescribeAddressIfHeap(addr);
   ReportErrorSummary("new-delete-type-mismatch", &stack);
   Report("HINT: if you don't care about these errors you may set "
          "ASAN_OPTIONS=new_delete_type_mismatch=0\n");
 }
 
 void ReportFreeNotMalloced(uptr addr, BufferedStackTrace *free_stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
   char tname[128];
   u32 curr_tid = GetCurrentTidOrInvalid();
   Report("ERROR: AddressSanitizer: attempting free on address "
              "which was not malloc()-ed: %p in thread T%d%s\n", addr,
          curr_tid, ThreadNameWithParenthesis(curr_tid, tname, sizeof(tname)));
   Printf("%s", d.EndWarning());
   CHECK_GT(free_stack->size, 0);
   ScarinessScore::PrintSimple(40, "bad-free");
   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
   stack.Print();
-  DescribeHeapAddress(addr, 1);
+  DescribeAddressIfHeap(addr);
   ReportErrorSummary("bad-free", &stack);
 }
 
 void ReportAllocTypeMismatch(uptr addr, BufferedStackTrace *free_stack,
                              AllocType alloc_type,
                              AllocType dealloc_type) {
   static const char *alloc_names[] =
     {"INVALID", "malloc", "operator new", "operator new []"};
   static const char *dealloc_names[] =
     {"INVALID", "free", "operator delete", "operator delete []"};
   CHECK_NE(alloc_type, dealloc_type);
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
   Report("ERROR: AddressSanitizer: alloc-dealloc-mismatch (%s vs %s) on %p\n",
         alloc_names[alloc_type], dealloc_names[dealloc_type], addr);
   Printf("%s", d.EndWarning());
   CHECK_GT(free_stack->size, 0);
   ScarinessScore::PrintSimple(10, "alloc-dealloc-mismatch");
   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
   stack.Print();
-  DescribeHeapAddress(addr, 1);
+  DescribeAddressIfHeap(addr);
   ReportErrorSummary("alloc-dealloc-mismatch", &stack);
   Report("HINT: if you don't care about these errors you may set "
          "ASAN_OPTIONS=alloc_dealloc_mismatch=0\n");
 }
 
 void ReportMallocUsableSizeNotOwned(uptr addr, BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
   Report("ERROR: AddressSanitizer: attempting to call "
              "malloc_usable_size() for pointer which is "
              "not owned: %p\n", addr);
   Printf("%s", d.EndWarning());
   stack->Print();
-  DescribeHeapAddress(addr, 1);
+  DescribeAddressIfHeap(addr);
   ReportErrorSummary("bad-malloc_usable_size", stack);
 }
 
 void ReportSanitizerGetAllocatedSizeNotOwned(uptr addr,
                                              BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;
   Decorator d;
   Printf("%s", d.Warning());
   Report("ERROR: AddressSanitizer: attempting to call "
              "__sanitizer_get_allocated_size() for pointer which is "
              "not owned: %p\n", addr);
   Printf("%s", d.EndWarning());
   stack->Print();
-  DescribeHeapAddress(addr, 1);
+  DescribeAddressIfHeap(addr);
   ReportErrorSummary("bad-__sanitizer_get_allocated_size", stack);
 }
 
 void ReportStringFunctionMemoryRangesOverlap(const char *function,
                                              const char *offset1, uptr length1,
                                              const char *offset2, uptr length2,
                                              BufferedStackTrace *stack) {
   ScopedInErrorReport in_report;

 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",
              addr);
   PrintZoneForPointer(addr, zone_ptr, zone_name);
   stack->Print();
-  DescribeHeapAddress(addr, 1);
+  DescribeAddressIfHeap(addr);
 }
 
 // -------------- SuppressErrorReport -------------- {{{1
 // Avoid error reports duplicating for ASan recover mode.
 static bool SuppressErrorReport(uptr pc) {
   if (!common_flags()->suppress_equal_pcs) return false;
   for (unsigned i = 0; i < kAsanBuggyPcPoolSize; i++) {
     uptr cmp = atomic_load_relaxed(&AsanBuggyPcPool[i]);