GCC_CET_HOST_FLAGS: Check if host supports multi-byte NOPs

Check if host supports multi-byte NOPs before enabling CET on host.

config/

	PR binutils/27397
	* cet.m4 (GCC_CET_HOST_FLAGS): Check if host supports multi-byte
	NOPs.

libiberty/

	PR binutils/27397
	* configure: Regenerated.

config/ChangeLog

@@ -1,3 +1,9 @@
+2021-03-18  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR binutils/27397
+	* cet.m4 (GCC_CET_HOST_FLAGS): Check if host supports multi-byte
+	NOPs.
+
 2021-02-13  Mike Frysinger  <vapier@gentoo.org>
 
 	* debuginfod.m4: Delete m4_include(../config/pkg.m4).

config/cet.m4

@@ -130,6 +130,18 @@ fi
 if test x$may_have_cet = xyes; then
   if test x$cross_compiling = xno; then
     AC_TRY_RUN([
+int
+main ()
+{
+  asm ("endbr32");
+  return 0;
+}
+    ],
+    [have_multi_byte_nop=yes],
+    [have_multi_byte_nop=no])
+    have_cet=no
+    if test x$have_multi_byte_nop = xyes; then
+      AC_TRY_RUN([
 static void
 foo (void)
 {
@@ -155,9 +167,10 @@ main ()
   bar ();
   return 0;
 }
-    ],
-    [have_cet=no],
-    [have_cet=yes])
+      ],
+      [have_cet=no],
+      [have_cet=yes])
+    fi
     if test x$enable_cet = xno -a x$have_cet = xyes; then
       AC_MSG_ERROR([Intel CET must be enabled on Intel CET enabled host])
     fi

libiberty/ChangeLog

@@ -1,3 +1,8 @@
+2021-03-18  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR binutils/27397
+	* configure: Regenerated.
+
 2021-01-11  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR ld/27173

libiberty/configure

@@ -5539,6 +5539,34 @@ else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+int
+main ()
+{
+  asm ("endbr32");
+  return 0;
+}
+
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+  have_multi_byte_nop=yes
+else
+  have_multi_byte_nop=no
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+    have_cet=no
+    if test x$have_multi_byte_nop = xyes; then
+      if test "$cross_compiling" = yes; then :
+  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot run test program while cross compiling
+See \`config.log' for more details" "$LINENO" 5; }
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
 static void
 foo (void)
 {
@@ -5575,6 +5603,7 @@ rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
   conftest.$ac_objext conftest.beam conftest.$ac_ext
 fi
 
+    fi
     if test x$enable_cet = xno -a x$have_cet = xyes; then
       as_fn_error $? "Intel CET must be enabled on Intel CET enabled host" "$LINENO" 5
     fi