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# SYNOPSIS
#
# AX_CHECK_CATCHABLE_SEGV
#
# DESCRIPTION
#
# Check whether segmentation violations can be caught using signal handlers.
#serial 1
AC_DEFUN([AX_CHECK_CATCHABLE_SEGV], [dnl
AC_PREREQ(2.64)
AS_VAR_PUSHDEF([CACHEVAR], [ax_cv_check_[]_AC_LANG_ABBREV[]CATCHABLE_SEGV])dnl
AC_CACHE_CHECK([whether segmentation violations can be caught when using the _AC_LANG compiler], CACHEVAR, [
AC_RUN_IFELSE([
AC_LANG_PROGRAM([[
#include <signal.h>
#include <stdlib.h>
static void sig(int _) { exit(0); }
]], [[
volatile unsigned char * volatile x = (volatile unsigned char *) malloc(8);
size_t i;
signal(SIGSEGV, sig);
signal(SIGBUS, sig);
#if !defined(__SANITIZE_ADDRESS__) && !defined(__EMSCRIPTEN__)
for (i = 0; i < 10000000; i += 1024) { x[-i] = x[i] = (unsigned char) i; }
#endif
free((void *) x);
exit(1)
]])],
[AS_VAR_SET(CACHEVAR, [yes])],
[AS_VAR_SET(CACHEVAR, [no])],
[AS_VAR_SET(CACHEVAR, [unknown])]
)
])
AS_VAR_IF(CACHEVAR, yes,
[AC_DEFINE([HAVE_CATCHABLE_SEGV], [1], [Define if segmentation violations can be caught using signal handlers])],
[AC_MSG_WARN([On this platform, segmentation violations cannot be caught using signal handlers. This is expected if you enabled a tool such as Address Sanitizer (-fsanitize=address), but be aware that using Address Sanitizer may also significantly reduce performance.])]
)
AS_VAR_POPDEF([CACHEVAR])dnl
])
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