Currently gcc trunk fails to bootstrap on powerpc-apple-darwin9, using the
default
system compiler, in libbacktrace due to the absence of _Unwind_GetIPInfo() in
the
unwind.h header of Apple gcc 4.0.1 compiler. The attached patch eliminates this
failure by enhancing the configure.ac test for the _Unwind_GetIPInfo() function
to
also test for its function declaration using
-Werror-implicit-function-declaration.
This change allows HAVE_GETIPINFO to remain properly undefined in stage 1 when
using the gcc 4.0.1 compiler but not in later stages with the built compiler.
It also properly leaves HAVE_GETIPINFO undefined when using the clang compiler
from Xcode 4.2 which lacks an unwind.h header but defines it for clang from
Xcode 4.5.1 which does. Also tested on x86_64 Fedora 15 without regression in
detection of _Unwind_GetIPInfo(). Rewritten to use AC_MSG_CHECKING,
AC_COMPILE_IFELSE,
AC_LANG_PROGRAM and AC_MSG_RESULT instead of AC_TRY_COMPILE(). Okay for gcc
trunk?
Jack
libbacktrace/
2012-10-26 Jack Howarth <howa...@bromo.med.uc.edu>
target/PR55061
* configure.ac: Check for _Unwind_GetIPInfo function declaration.
* configure: Regenerate.
Index: libbacktrace/configure.ac
===================================================================
--- libbacktrace/configure.ac (revision 192845)
+++ libbacktrace/configure.ac (working copy)
@@ -129,8 +129,18 @@ AC_SUBST(WARN_FLAGS)
if test -n "${with_target_subdir}"; then
GCC_CHECK_UNWIND_GETIPINFO
else
- AC_CHECK_FUNC(_Unwind_GetIPInfo, [have_unwind_getipinfo=yes],
- [have_unwind_getipinfo=no])
+ ac_save_CFFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS -Werror-implicit-function-declaration"
+ AC_MSG_CHECKING([for _Unwind_GetIPInfo])
+ AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM(
+ [#include "unwind.h"
+ struct _Unwind_Context *context;
+ int ip_before_insn = 0;],
+ [return _Unwind_GetIPInfo (context, &ip_before_insn);])],
+ [have_unwind_getipinfo=yes], [have_unwind_getipinfo=no])
+ CFLAGS="$ac_save_CFLAGS"
+ AC_MSG_RESULT([$have_unwind_getipinfo])
if test "$have_unwind_getipinfo" = "yes"; then
AC_DEFINE(HAVE_GETIPINFO, 1, [Define if _Unwind_GetIPInfo is available.])
fi
