scons: Resolve backtrace implementation existence testing failure

Change backtrace implementation testing code not to have NULL pointer.

SCons fails to find backtrace implementation even if it exists.
The implementation testing code contains NULL pointers as a backtrace
buffer argument. Some compilers check the buffer is NULL pointed
or not, and generate a compilation error.

Change-Id: Icc5bc9a887b7a6bbc804b5b8a5a35a935c78a922
Reviewed-on: https://gem5-review.googlesource.com/7681
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

diff --git a/SConstruct b/SConstruct
index 09c3476d73feae03f65dee73bb8723f63b503661..df647e72584814b77c368d7cb4c0f7851464234c 100755 (executable)
--- a/SConstruct
+++ b/SConstruct
@@ -814,11 +814,12 @@ if not GetOption('without_tcmalloc'):
 # list will be used by default.
 backtrace_impls = [ "none" ]
 
 # list will be used by default.
 backtrace_impls = [ "none" ]
 

-if conf.CheckLibWithHeader(None, 'execinfo.h', 'C',
-                           'backtrace_symbols_fd((void*)0, 0, 0);'):
+backtrace_checker = 'char temp;' + \
+    ' backtrace_symbols_fd((void*)&temp, 0, 0);'
+if conf.CheckLibWithHeader(None, 'execinfo.h', 'C', backtrace_checker):

     backtrace_impls.append("glibc")
 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',
     backtrace_impls.append("glibc")
 elif conf.CheckLibWithHeader('execinfo', 'execinfo.h', 'C',

-                           'backtrace_symbols_fd((void*)0, 0, 0);'):
+                             backtrace_checker):

     # NetBSD and FreeBSD need libexecinfo.
     backtrace_impls.append("glibc")
     main.Append(LIBS=['execinfo'])
     # NetBSD and FreeBSD need libexecinfo.
     backtrace_impls.append("glibc")
     main.Append(LIBS=['execinfo'])