Explicitly specify whether to emit frame pointers by default.

base/debug/stack_trace.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_DEBUG_STACK_TRACE_H_
 #define BASE_DEBUG_STACK_TRACE_H_
 
 #include <stddef.h>
 
 #include <iosfwd>
 #include <string>
 
 #include "base/base_export.h"
+#include "base/debug/debugging_flags.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 
 #if defined(OS_POSIX)
 #include <unistd.h>
 #endif
 
 #if defined(OS_WIN)
 struct _EXCEPTION_POINTERS;
 struct _CONTEXT;
 #endif
 
-// TODO(699863): Clean up HAVE_TRACE_STACK_FRAME_POINTERS.
-#if defined(OS_POSIX)
-
-#if defined(__i386__) || defined(__x86_64__)
-#define HAVE_TRACE_STACK_FRAME_POINTERS 1
-#elif defined(__arm__) && !defined(__thumb__)
-#define HAVE_TRACE_STACK_FRAME_POINTERS 1
-#else  // defined(__arm__) && !defined(__thumb__)
-#define HAVE_TRACE_STACK_FRAME_POINTERS 0
-#endif  // defined(__arm__) && !defined(__thumb__)
-
-#elif defined(OS_WIN)
-#define HAVE_TRACE_STACK_FRAME_POINTERS 1
-
-#else  // defined(OS_WIN)
-#define HAVE_TRACE_STACK_FRAME_POINTERS 0
-#endif  // defined(OS_WIN)
+// Unwinding using frame pointers requires stack traces to have frame pointers
+// by default. This still doesn't work on thumb architectures, due to an llvm
+// bug. https://bugs.llvm.org/show_bug.cgi?id=18505#c5
+#if ENABLED_FRAME_POINTERS && !(defined(__arm__) && defined(__thumb__))

[brettw, 2017/04/03 21:17:42]

This isn't how you use the buildflag header. So you will want to do
BUILDFLAG(...) and also double-check that this is getting set the way you want.

+#define CAN_UNWIND_WITH_FRAME_POINTERS 1
+#else
+#define CAN_UNWIND_WITH_FRAME_POINTERS 0
+#endif
 
 namespace base {
 namespace debug {
 
 // Enables stack dump to console output on exception and signals.
 // When enabled, the process will quit immediately. This is meant to be used in
 // unit_tests only! This is not thread-safe: only call from main thread.
 // In sandboxed processes, this has to be called before the sandbox is turned
 // on.
 // Calling this function on Linux opens /proc/self/maps and caches its
 // contents. In non-official builds, this function also opens the object files
 // that are loaded in memory and caches their file descriptors (this cannot be
 // done in official builds because it has security implications).
 BASE_EXPORT bool EnableInProcessStackDumping();
 
 // Returns end of the stack, or 0 if we couldn't get it.
-#if HAVE_TRACE_STACK_FRAME_POINTERS
+#if CAN_UNWIND_WITH_FRAME_POINTERS
 BASE_EXPORT uintptr_t GetStackEnd();
 #endif
 
 // A stacktrace can be helpful in debugging. For example, you can include a
 // stacktrace member in a object (probably around #ifndef NDEBUG) so that you
 // can later see where the given object was created from.
 class BASE_EXPORT StackTrace {
  public:
   // Creates a stacktrace from the current location.
   StackTrace();
@@ skipping 42 matching lines @@
   // so set it to 62. Even if on POSIX it could be a larger value, it usually
   // doesn't give much more information.
   static const int kMaxTraces = 62;
 
   void* trace_[kMaxTraces];
 
   // The number of valid frames in |trace_|.
   size_t count_;
 };
 
-#if HAVE_TRACE_STACK_FRAME_POINTERS
+#if CAN_UNWIND_WITH_FRAME_POINTERS
 // Traces the stack by using frame pointers. This function is faster but less
 // reliable than StackTrace. It should work for debug and profiling builds,
 // but not for release builds (although there are some exceptions).
 //
 // Writes at most |max_depth| frames (instruction pointers) into |out_trace|
 // after skipping |skip_initial| frames. Note that the function itself is not
 // added to the trace so |skip_initial| should be 0 in most cases.
 // Returns number of frames written.
 BASE_EXPORT size_t TraceStackFramePointers(const void** out_trace,
                                            size_t max_depth,
@@ skipping 44 matching lines @@
 
  private:
   void* fp_;
   void* parent_fp_;
   void* original_parent_fp_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedStackFrameLinker);
 };
 #endif  // !defined(OS_WIN)
 
-#endif  // HAVE_TRACE_STACK_FRAME_POINTERS
+#endif  // CAN_UNWIND_WITH_FRAME_POINTERS
 
 namespace internal {
 
 #if defined(OS_POSIX) && !defined(OS_ANDROID)
 // POSIX doesn't define any async-signal safe function for converting
 // an integer to ASCII. We'll have to define our own version.
 // itoa_r() converts a (signed) integer to ASCII. It returns "buf", if the
 // conversion was successful or NULL otherwise. It never writes more than "sz"
 // bytes. Output will be truncated as needed, and a NUL character is always
 // appended.
 BASE_EXPORT char *itoa_r(intptr_t i,
                          char *buf,
                          size_t sz,
                          int base,
                          size_t padding);
 #endif  // defined(OS_POSIX) && !defined(OS_ANDROID)
 
 }  // namespace internal
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_STACK_TRACE_H_