Cleaner fall-back stack capture for --enable-heap-profiling=native.

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.
+// Fast stack trace capture using frame pointers is only available under POSIX
+// platforms, and only for certain architectures, and only when frame pointers
+// are enabled in the build.
 #if defined(OS_POSIX)
+#if BUILDFLAG(ENABLE_PROFILING) || !defined(NDEBUG)
 
 #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__)
+#else  //  defined(__arm__) && !defined(__thumb__)
 #define HAVE_TRACE_STACK_FRAME_POINTERS 0
-#endif  // defined(__arm__) && !defined(__thumb__)
+#endif  //  defined(__arm__) && !defined(__thumb__)
 
-#elif defined(OS_WIN)
-#define HAVE_TRACE_STACK_FRAME_POINTERS 1
+#else  //  BUILDFLAG(ENABLE_PROFILING) || !defined(NDEBUG)
+#define HAVE_TRACE_STACK_FRAME_POINTERS 0
+#endif  //  BUILDFLAG(ENABLE_PROFILING) || !defined(NDEBUG)
 
-#else  // defined(OS_WIN)
+#else  // defined(OS_POSIX)
 #define HAVE_TRACE_STACK_FRAME_POINTERS 0
-#endif  // defined(OS_WIN)
+#endif  // defined(OS_POSIX)
 
 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
@@ skipping 72 matching lines @@
 // 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,
                                            size_t skip_initial);
 
-#if !defined(OS_WIN)
 // Links stack frame |fp| to |parent_fp|, so that during stack unwinding
 // TraceStackFramePointers() visits |parent_fp| after visiting |fp|.
 // Both frame pointers must come from __builtin_frame_address().
 // Destructor restores original linkage of |fp| to avoid corrupting caller's
 // frame register on return.
 //
 // This class can be used to repair broken stack frame chain in cases
 // when execution flow goes into code built without frame pointers:
 //
 // void DoWork() {
@@ skipping 29 matching lines @@
   ScopedStackFrameLinker(void* fp, void* parent_fp);
   ~ScopedStackFrameLinker();
 
  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
 
 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_