Use exact match in get_var_value

[deliverable/binutils-gdb.git] / config / cet.m4

diff --git a/config/cet.m4 b/config/cet.m4
index d9608699cd521a72e38a1e6184ffbd1862b4622b..c67fb4f35b65b84a88bcbebadaf8d12781025a75 100644 (file)
--- a/config/cet.m4
+++ b/config/cet.m4
@@ -3,16 +3,19 @@ dnl GCC_CET_FLAGS
 dnl    (SHELL-CODE_HANDLER)
 dnl
 AC_DEFUN([GCC_CET_FLAGS],[dnl
-GCC_ENABLE(cet, no, ,[enable Intel CET in target libraries],
+GCC_ENABLE(cet, auto, ,[enable Intel CET in target libraries],
           permit yes|no|auto)
 AC_MSG_CHECKING([for CET support])
 
+# NB: Avoid nested save_CFLAGS and save_LDFLAGS.
 case "$host" in
   i[[34567]]86-*-linux* | x86_64-*-linux*)
     case "$enable_cet" in
       auto)
        # Check if target supports multi-byte NOPs
-       # and if assembler supports CET insn.
+       # and if compiler and assembler support CET insn.
+       cet_save_CFLAGS="$CFLAGS"
+       CFLAGS="$CFLAGS -fcf-protection"
        AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
          [],
@@ -25,6 +28,7 @@ asm ("setssbsy");
          ])],
         [enable_cet=yes],
         [enable_cet=no])
+       CFLAGS="$cet_save_CFLAGS"
        ;;
       yes)
        # Check if assembler supports CET.
@@ -61,12 +65,12 @@ AC_MSG_CHECKING([for CET support])
 case "$host" in
   i[[34567]]86-*-linux* | x86_64-*-linux*)
     may_have_cet=yes
-    save_CFLAGS="$CFLAGS"
+    cet_save_CFLAGS="$CFLAGS"
     CFLAGS="$CFLAGS -fcf-protection"
     case "$enable_cet" in
       auto)
        # Check if target supports multi-byte NOPs
-       # and if assembler supports CET insn.
+       # and if compiler and assembler support CET.
        AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
          [],
@@ -81,16 +85,29 @@ asm ("setssbsy");
         [enable_cet=no])
        ;;
       yes)
-       # Check if assembler supports CET.
+       # Check if compiler and assembler support CET.
        AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
          [],
          [asm ("setssbsy");])],
-        [],
-        [AC_MSG_ERROR([assembler with CET support is required for --enable-cet])])
+        [support_cet=yes],
+        [support_cet=no])
+       if test $support_cet = "no"; then
+         if test x$enable_bootstrap != xno \
+            && test -z "${with_build_subdir}" \
+            && (test ! -f ../stage_current \
+                || test `cat ../stage_current` != "stage1"); then
+           # Require CET support only for the final GCC build.
+           AC_MSG_ERROR([compiler and assembler with CET support are required for --enable-cet])
+         else
+           # Don't enable CET without CET support for non-bootstrap
+           # build, in stage1 nor for build support.
+           enable_cet=no
+         fi
+       fi
        ;;
     esac
-    CFLAGS="$save_CFLAGS"
+    CFLAGS="$cet_save_CFLAGS"
     ;;
   *)
     may_have_cet=no
@@ -98,9 +115,9 @@ asm ("setssbsy");
     ;;
 esac
 
-save_CFLAGS="$CFLAGS"
+cet_save_CFLAGS="$CFLAGS"
 CFLAGS="$CFLAGS -fcf-protection=none"
-save_LDFLAGS="$LDFLAGS"
+cet_save_LDFLAGS="$LDFLAGS"
 LDFLAGS="$LDFLAGS -Wl,-z,ibt,-z,shstk"
 if test x$may_have_cet = xyes; then
   # Check whether -fcf-protection=none -Wl,-z,ibt,-z,shstk work.
@@ -156,6 +173,6 @@ if test x$enable_cet = xyes; then
 else
   AC_MSG_RESULT([no])
 fi
-CFLAGS="$save_CFLAGS"
-LDFLAGS="$save_LDFLAGS"
+CFLAGS="$cet_save_CFLAGS"
+LDFLAGS="$cet_save_LDFLAGS"
 ])