disable more stacktrace usage in debug uclibc builds

base/debug/leak_tracker.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_LEAK_TRACKER_H_
 #define BASE_DEBUG_LEAK_TRACKER_H_
 
-// Only enable leak tracking in debug builds.
-#ifndef NDEBUG
+// Only enable leak tracking in non-uClibc debug builds.
+#if !defined(NDEBUG) && !defined(__UCLIBC__)

[Mark Mentovai, 2014/04/16 13:11:25]

Nothing says __UCLIBC__ will be defined here in a µClibc build. You haven’t
#included anything that would cause it to be defined.

[Mostyn Bramley-Moore, 2014/04/16 23:20:14]

Ahh, right.  

In my local branch I have some additional headers injected via the command line
(not something you would want me to submit) which include some other system
headers that in turn include features.h.

This file probably should include build/build_config.h, which should make sure
that this macro is set on uclibc builds.  However, it looks like that file needs
to add something like the following to build/build_config.h:

#ifdef OS_POSIX
// Make sure we have __GLIBC__ and/or __UCLIBC__ macros if we're building with
either of these C libraries
#include <features.h>
#endif

(Though perhaps OS_LINUX would be better?)

[Mark Mentovai, 2014/04/17 22:24:41]

Mostyn Bramley-Moore wrote:
<features.h> isn’t a standard header, so use OS_LINUX instead of OS_POSIX. I
don’t know if there are any Linux C libraries we care about that don’t have
<features.h>, but I do know that there are POSIXes that we care about that don’t
have this header. Mac OS X is the prime example.

Or, you could just include some other standard header that you know will cause
<features.h> and thus __UCLIBC__ to be defined if µClibc is the standard library
in use. I checked when you used __UCLIBC__ in other files, and there were
standard headers present that would have caused <features.h> to be included and
thus __UCLIBC__ to be defined.

[Mostyn Bramley-Moore, 2014/04/17 22:35:33]

I though about this a bit, but wasn't sure which system header would be most
suitable to include.  How about unistd.h?

 #define ENABLE_LEAK_TRACKER
 #endif
 
 #ifdef ENABLE_LEAK_TRACKER
 #include "base/containers/linked_list.h"
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
 #endif  // ENABLE_LEAK_TRACKER
 
 // LeakTracker is a helper to verify that all instances of a class
@@ skipping 107 matching lines @@
 
   StackTrace allocation_stack_;
 };
 
 #endif  // ENABLE_LEAK_TRACKER
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_LEAK_TRACKER_H_