[pulseaudio-discuss] [PATCH webrtc-audio-processing] Proper detection of cxxabi.h and execinfo.h

[Arun Raghavan]

On Sat, 6 Aug 2016, at 02:59 PM, Thomas Petazzoni wrote:
> The current code in webrtc/base/checks.cc assumes that if __GLIBCXX__ is
> defined and __UCLIBC__ is not defined, then both cxxabi.h and execinfo.h
> will be available.
> 
> Unfortunately, this is not correct with the musl C library:
> 
>  - It defines __GLIBCXX__
>  - It does not define __UCLIBC__ (it's not uClibc after all!)
>  - But it also doesn't provide execinfo.h
> 
> Therefore, in order to make things work properly, we switch to proper
> autoconf checks for cxxabi.h and execinfo.h, and only use the backtrace
> functionality if both are provided.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> ---
>  configure.ac          | 2 ++
>  webrtc/base/checks.cc | 4 ++--
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index acbb3e2..ff4c752 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -45,6 +45,8 @@ AC_SUBST(GNUSTL_CFLAGS)
>  # Borrowed from gst-plugins-bad
>  AC_CHECK_HEADER(MobileCoreServices/MobileCoreServices.h, HAVE_IOS="yes",
>  HAVE_IOS="no", [-])
>  
> +AC_CHECK_HEADERS([cxxabi.h execinfo.h])
> +
>  # Based on gst-plugins-bad configure.ac and defines in
>  # <chromium source>/build/config/BUILDCONFIG.gn and
>  # webrtc/BUILD.gn
> diff --git a/webrtc/base/checks.cc b/webrtc/base/checks.cc
> index 49a31f2..05d23a6 100644
> --- a/webrtc/base/checks.cc
> +++ b/webrtc/base/checks.cc
> @@ -16,7 +16,7 @@
>  #include <cstdio>
>  #include <cstdlib>
>  
> -#if defined(__GLIBCXX__) && !defined(__UCLIBC__)
> +#if defined(HAVE_CXX_ABI_H) && defined(HAVE_EXECINFO_H)
>  #include <cxxabi.h>
>  #include <execinfo.h>
>  #endif
> @@ -55,7 +55,7 @@ void PrintError(const char* format, ...) {
>  // to get usable symbols on Linux. This is copied from V8. Chromium has
>  a more
>  // advanced stace trace system; also more difficult to copy.
>  void DumpBacktrace() {
> -#if defined(__GLIBCXX__) && !defined(__UCLIBC__)
> +#if defined(HAVE_CXX_ABI_H) && defined(HAVE_EXECINFO_H)
>    void* trace[100];
>    int size = backtrace(trace, sizeof(trace) / sizeof(*trace));
>    char** symbols = backtrace_symbols(trace, size);
> -- 

Hmm, this one's a bit tricky. Again, changing our copy of the webrtc.org
code will make maintenance a pain, so I'd prefer for such changes to go
upstream. They're not using autoconf, so you might need to use a
different mechanism.

-- Arun