Add -fstack-clash-protection to CFLAGS in debug builds if available

Signed-off-by: Allan McRae <allan@archlinux.org>

2 files changed, 20 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index ba54c2dd..6f336022 100644
--- a/configure.ac
+++ b/configure.ac
@@ -443,6 +443,7 @@ if test "x$debug" = "xyes" ; then
 	# Check for -fstack-protector availability
 	GCC_STACK_PROTECT_LIB
 	GCC_STACK_PROTECT_CC
+	GCC_STACK_CLASH_PROTECTION
 	GCC_FORTIFY_SOURCE_CC
 	WARNING_CFLAGS="-g -Wall -Werror"
 else
diff --git a/m4/acinclude.m4 b/m4/acinclude.m4
index 15bb31e8..845c8286 100644
--- a/m4/acinclude.m4
+++ b/m4/acinclude.m4
@@ -38,6 +38,25 @@ AC_DEFUN([GCC_STACK_PROTECT_CC],[
   fi
 ])
 
+dnl GCC_STACK_CLASH_PROTECTION
+dnl check -fstack-clash-protection with the C compiler, if it exists then
+dnl updates CFLAGS
+AC_DEFUN([GCC_STACK_CLASH_PROTECTION],[
+  AC_LANG_ASSERT(C)
+  if test "X$CC" != "X"; then
+    AC_CACHE_CHECK([whether ${CC} accepts -fstack-clash-protection],
+      scp_cv_cc,
+      [scp_old_cflags="$CFLAGS"
+       CFLAGS="$CFLAGS -fstack-clash-protection"
+       AC_TRY_COMPILE(,, scp_cv_cc=yes, scp_cv_cc=no)
+       CFLAGS="$scp_old_cflags"
+      ])
+    if test $scp_cv_cc = yes; then
+      CFLAGS="$CFLAGS -fstack-clash-protection"
+    fi
+  fi
+])
+
 dnl GCC_FORTIFY_SOURCE_CC
 dnl checks -D_FORTIFY_SOURCE with the C compiler, if it exists then updates
 dnl CPPFLAGS