diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
new file mode 100644
index 000000000000..fd0c4a40eb40
--- /dev/null
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc
@@ -0,0 +1,223 @@
+//===-- sanitizer_stacktrace.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 shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_procmaps.h"
+#include "sanitizer_common/sanitizer_stacktrace.h"
+#include "sanitizer_common/sanitizer_symbolizer.h"
+
+namespace __sanitizer {
+static const char *StripPathPrefix(const char *filepath,
+                                   const char *strip_file_prefix) {
+  if (filepath == internal_strstr(filepath, strip_file_prefix))
+    return filepath + internal_strlen(strip_file_prefix);
+  return filepath;
+}
+
+// ----------------------- StackTrace ----------------------------- {{{1
+// PCs in stack traces are actually the return addresses, that is,
+// addresses of the next instructions after the call. That's why we
+// decrement them.
+static uptr patch_pc(uptr pc) {
+#ifdef __arm__
+  // Cancel Thumb bit.
+  pc = pc & (~1);
+#endif
+  return pc - 1;
+}
+
+void StackTrace::PrintStack(uptr *addr, uptr size,
+                            bool symbolize, const char *strip_file_prefix,
+                            SymbolizeCallback symbolize_callback ) {
+  MemoryMappingLayout proc_maps;
+  uptr frame_num = 0;
+  for (uptr i = 0; i < size && addr[i]; i++) {
+    uptr pc = patch_pc(addr[i]);
+    if (symbolize_callback) {
+      char buff[4096];
+      symbolize_callback((void*)pc, buff, sizeof(buff));
+      // We can't know anything about the string returned by external
+      // symbolizer, but if it starts with filename, try to strip path prefix
+      // from it.
+      Printf("  #%zu 0x%zx %s\n", frame_num, pc,
+             StripPathPrefix(buff, strip_file_prefix));
+      frame_num++;
+      continue;
+    }
+    AddressInfo addr_frames[64];
+    uptr addr_frames_num =
+      symbolize ? SymbolizeCode(pc, addr_frames, ARRAY_SIZE(addr_frames)) : 0;
+    if (addr_frames_num > 0) {
+      for (uptr j = 0; j < addr_frames_num; j++) {
+        AddressInfo &info = addr_frames[j];
+        Printf("    #%zu 0x%zx", frame_num, pc);
+        if (info.function) {
+          Printf(" in %s", info.function);
+        }
+        if (info.file) {
+          Printf(" %s:%d:%d", StripPathPrefix(info.file, strip_file_prefix),
+                 info.line, info.column);
+        } else if (info.module) {
+          Printf(" (%s+0x%zx)", StripPathPrefix(info.module, strip_file_prefix),
+                 info.module_offset);
+        }
+        Printf("\n");
+        info.Clear();
+        frame_num++;
+      }
+    } else {
+      uptr offset;
+      char filename[4096];
+      if (proc_maps.GetObjectNameAndOffset(pc, &offset,
+                                           filename, sizeof(filename))) {
+        Printf("    #%zu 0x%zx (%s+0x%zx)\n", frame_num, pc,
+               StripPathPrefix(filename, strip_file_prefix), offset);
+      } else {
+        Printf("    #%zu 0x%zx\n", frame_num, pc);
+      }
+      frame_num++;
+    }
+  }
+}
+
+uptr StackTrace::GetCurrentPc() {
+  return GET_CALLER_PC();
+}
+
+void StackTrace::FastUnwindStack(uptr pc, uptr bp,
+                                 uptr stack_top, uptr stack_bottom) {
+  CHECK(size == 0 && trace[0] == pc);
+  size = 1;
+  uptr *frame = (uptr*)bp;
+  uptr *prev_frame = frame;
+  while (frame >= prev_frame &&
+         frame < (uptr*)stack_top - 2 &&
+         frame > (uptr*)stack_bottom &&
+         size < max_size) {
+    uptr pc1 = frame[1];
+    if (pc1 != pc) {
+      trace[size++] = pc1;
+    }
+    prev_frame = frame;
+    frame = (uptr*)frame[0];
+  }
+}
+
+// On 32-bits we don't compress stack traces.
+// On 64-bits we compress stack traces: if a given pc differes slightly from
+// the previous one, we record a 31-bit offset instead of the full pc.
+SANITIZER_INTERFACE_ATTRIBUTE
+uptr StackTrace::CompressStack(StackTrace *stack, u32 *compressed, uptr size) {
+#if __WORDSIZE == 32
+  // Don't compress, just copy.
+  uptr res = 0;
+  for (uptr i = 0; i < stack->size && i < size; i++) {
+    compressed[i] = stack->trace[i];
+    res++;
+  }
+  if (stack->size < size)
+    compressed[stack->size] = 0;
+#else  // 64 bits, compress.
+  uptr prev_pc = 0;
+  const uptr kMaxOffset = (1ULL << 30) - 1;
+  uptr c_index = 0;
+  uptr res = 0;
+  for (uptr i = 0, n = stack->size; i < n; i++) {
+    uptr pc = stack->trace[i];
+    if (!pc) break;
+    if ((s64)pc < 0) break;
+    // Printf("C pc[%zu] %zx\n", i, pc);
+    if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) {
+      uptr offset = (s64)(pc - prev_pc);
+      offset |= (1U << 31);
+      if (c_index >= size) break;
+      // Printf("C co[%zu] offset %zx\n", i, offset);
+      compressed[c_index++] = offset;
+    } else {
+      uptr hi = pc >> 32;
+      uptr lo = (pc << 32) >> 32;
+      CHECK((hi & (1 << 31)) == 0);
+      if (c_index + 1 >= size) break;
+      // Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo);
+      compressed[c_index++] = hi;
+      compressed[c_index++] = lo;
+    }
+    res++;
+    prev_pc = pc;
+  }
+  if (c_index < size)
+    compressed[c_index] = 0;
+  if (c_index + 1 < size)
+    compressed[c_index + 1] = 0;
+#endif  // __WORDSIZE
+
+  // debug-only code
+#if 0
+  StackTrace check_stack;
+  UncompressStack(&check_stack, compressed, size);
+  if (res < check_stack.size) {
+    Printf("res %zu check_stack.size %zu; c_size %zu\n", res,
+           check_stack.size, size);
+  }
+  // |res| may be greater than check_stack.size, because
+  // UncompressStack(CompressStack(stack)) eliminates the 0x0 frames.
+  CHECK(res >= check_stack.size);
+  CHECK(0 == REAL(memcmp)(check_stack.trace, stack->trace,
+                          check_stack.size * sizeof(uptr)));
+#endif
+
+  return res;
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void StackTrace::UncompressStack(StackTrace *stack,
+                                 u32 *compressed, uptr size) {
+#if __WORDSIZE == 32
+  // Don't uncompress, just copy.
+  stack->size = 0;
+  for (uptr i = 0; i < size && i < kStackTraceMax; i++) {
+    if (!compressed[i]) break;
+    stack->size++;
+    stack->trace[i] = compressed[i];
+  }
+#else  // 64 bits, uncompress
+  uptr prev_pc = 0;
+  stack->size = 0;
+  for (uptr i = 0; i < size && stack->size < kStackTraceMax; i++) {
+    u32 x = compressed[i];
+    uptr pc = 0;
+    if (x & (1U << 31)) {
+      // Printf("U co[%zu] offset: %x\n", i, x);
+      // this is an offset
+      s32 offset = x;
+      offset = (offset << 1) >> 1;  // remove the 31-byte and sign-extend.
+      pc = prev_pc + offset;
+      CHECK(pc);
+    } else {
+      // CHECK(i + 1 < size);
+      if (i + 1 >= size) break;
+      uptr hi = x;
+      uptr lo = compressed[i+1];
+      // Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo);
+      i++;
+      pc = (hi << 32) | lo;
+      if (!pc) break;
+    }
+    // Printf("U pc[%zu] %zx\n", stack->size, pc);
+    stack->trace[stack->size++] = pc;
+    prev_pc = pc;
+  }
+#endif  // __WORDSIZE
+}
+
+}  // namespace __sanitizer
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
new file mode 100644
index 000000000000..454e5ecc9768
--- /dev/null
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
@@ -0,0 +1,75 @@
+//===-- sanitizer_stacktrace.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 shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+//===----------------------------------------------------------------------===//
+#ifndef SANITIZER_STACKTRACE_H
+#define SANITIZER_STACKTRACE_H
+
+#include "sanitizer_common/sanitizer_internal_defs.h"
+
+namespace __sanitizer {
+
+static const uptr kStackTraceMax = 64;
+
+struct StackTrace {
+  typedef bool (*SymbolizeCallback)(const void *pc, char *out_buffer,
+                                     int out_size);
+  uptr size;
+  uptr max_size;
+  uptr trace[kStackTraceMax];
+  static void PrintStack(uptr *addr, uptr size,
+                         bool symbolize, const char *strip_file_prefix,
+                         SymbolizeCallback symbolize_callback);
+  void CopyTo(uptr *dst, uptr dst_size) {
+    for (uptr i = 0; i < size && i < dst_size; i++)
+      dst[i] = trace[i];
+    for (uptr i = size; i < dst_size; i++)
+      dst[i] = 0;
+  }
+
+  void CopyFrom(uptr *src, uptr src_size) {
+    size = src_size;
+    if (size > kStackTraceMax) size = kStackTraceMax;
+    for (uptr i = 0; i < size; i++) {
+      trace[i] = src[i];
+    }
+  }
+
+  void FastUnwindStack(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom);
+
+  static uptr GetCurrentPc();
+
+  static uptr CompressStack(StackTrace *stack,
+                            u32 *compressed, uptr size);
+  static void UncompressStack(StackTrace *stack,
+                              u32 *compressed, uptr size);
+};
+
+}  // namespace __sanitizer
+
+// Use this macro if you want to print stack trace with the caller
+// of the current function in the top frame.
+#define GET_CALLER_PC_BP_SP \
+  uptr bp = GET_CURRENT_FRAME();              \
+  uptr pc = GET_CALLER_PC();                  \
+  uptr local_stack;                           \
+  uptr sp = (uptr)&local_stack
+
+// Use this macro if you want to print stack trace with the current
+// function in the top frame.
+#define GET_CURRENT_PC_BP_SP \
+  uptr bp = GET_CURRENT_FRAME();              \
+  uptr pc = StackTrace::GetCurrentPc();   \
+  uptr local_stack;                           \
+  uptr sp = (uptr)&local_stack
+
+
+#endif  // SANITIZER_STACKTRACE_H