From 5611e648542e5fdbb5a839ec21179ab979338839 Mon Sep 17 00:00:00 2001
From: itsimbal <itsimbal@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Mon, 19 Feb 2018 16:25:49 +0000
Subject: CET shouldn't be enabled in 32-bit run-time libraries by defualt

ENDBR32 and RDSSPD are multi-byte NOPs on x86-64 processors and
newer x86 processors, starting Pentium Pro.  They are UD on older
32-bit processors. Detect this at configure time and adjust the
default value for enable_cet. GCC will enable CET in 32-bit run-time
libraries in any case if --enable-cet is used to configure GCC.

	PR target/84148
	* config/cet.m4: Check if target support multi-byte NOPS (SSE).
	* libatomic/configure: Regenerate.
	* libbacktrace/configure: Likewise.
	* libgcc/configure: Likewise.
	* libgfortran/configure: Likewise.
	* libgomp/configure: Likewise.
	* libitm/configure: Likewise.
	* libmpx/configure: Likewise.
	* libobjc/configure: Likewise.
	* libquadmath/configure: Likewise.
	* libsanitizer/configure: Likewise.
	* libssp/configure: Likewise.
	* libstdc++-v3/configure: Likewise.
	* libvtv/configure: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@257809 138bc75d-0d04-0410-961f-82ee72b054a4
---
 libgomp/configure | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

(limited to 'libgomp/configure')

diff --git a/libgomp/configure b/libgomp/configure
index e7842b5519f..92b8142b0b1 100755
--- a/libgomp/configure
+++ b/libgomp/configure
@@ -15142,7 +15142,7 @@ fi
 
 # Plugins for offload execution, configure.ac fragment.  -*- mode: autoconf -*-
 #
-# Copyright (C) 2014-2017 Free Software Foundation, Inc.
+# Copyright (C) 2014-2018 Free Software Foundation, Inc.
 #
 # Contributed by Mentor Embedded.
 #
@@ -16633,18 +16633,28 @@ else
 fi
 
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for CET support" >&5
+$as_echo_n "checking for CET support... " >&6; }
+
 case "$host" in
   i[34567]86-*-linux* | x86_64-*-linux*)
     case "$enable_cet" in
       default)
-	# Check if assembler supports CET.
+	# Check if target supports multi-byte NOPs
+	# and if assembler supports CET insn.
 	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
 int
 main ()
 {
+
+#if !defined(__SSE2__)
+#error target does not support multi-byte NOPs
+#else
 asm ("setssbsy");
+#endif
+
   ;
   return 0;
 }
@@ -16684,6 +16694,11 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 esac
 if test x$enable_cet = xyes; then
   CET_FLAGS="-fcf-protection -mcet"
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
 fi
 
 XCFLAGS="$XCFLAGS $CET_FLAGS"
-- 
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