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diff --git a/third_party/glog/src/stacktrace_libunwind-inl.h b/third_party/glog/src/stacktrace_libunwind-inl.h
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+++ b/third_party/glog/src/stacktrace_libunwind-inl.h
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+// Copyright (c) 2005 - 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: Arun Sharma
+//
+// Produce stack trace using libunwind
+
+#include "utilities.h"
+
+extern "C" {
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+}
+#include "glog/raw_logging.h"
+#include "stacktrace.h"
+
+_START_GOOGLE_NAMESPACE_
+
+// Sometimes, we can try to get a stack trace from within a stack
+// trace, because libunwind can call mmap (maybe indirectly via an
+// internal mmap based memory allocator), and that mmap gets trapped
+// and causes a stack-trace request.  If were to try to honor that
+// recursive request, we'd end up with infinite recursion or deadlock.
+// Luckily, it's safe to ignore those subsequent traces.  In such
+// cases, we return 0 to indicate the situation.
+// We can use the GCC __thread syntax here since libunwind is not supported on
+// Windows.
+static __thread bool g_tl_entered; // Initialized to false.
+
+// If you change this function, also change GetStackFrames below.
+int GetStackTrace(void** result, int max_depth, int skip_count) {
+  void *ip;
+  int n = 0;
+  unw_cursor_t cursor;
+  unw_context_t uc;
+
+  if (g_tl_entered) {
+    return 0;
+  }
+  g_tl_entered = true;
+
+  unw_getcontext(&uc);
+  RAW_CHECK(unw_init_local(&cursor, &uc) >= 0, "unw_init_local failed");
+  skip_count++;         // Do not include the "GetStackTrace" frame
+
+  while (n < max_depth) {
+    int ret = unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip);
+    if (ret < 0)
+      break;
+    if (skip_count > 0) {
+      skip_count--;
+    } else {
+      result[n++] = ip;
+    }
+    ret = unw_step(&cursor);
+    if (ret <= 0)
+      break;
+  }
+
+  g_tl_entered = false;
+  return n;
+}
+
+_END_GOOGLE_NAMESPACE_