gcc/config/cet.m4

dnl
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],
	   permit yes|no|auto)
AC_MSG_CHECKING([for CET support])

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.
	AC_COMPILE_IFELSE(
	 [AC_LANG_PROGRAM(
	  [],
	  [
#if !defined(__SSE2__)
#error target does not support multi-byte NOPs
#else
asm ("setssbsy");
#endif
	  ])],
	 [enable_cet=yes],
	 [enable_cet=no])
	;;
      yes)
	# Check if assembler supports CET.
	AC_COMPILE_IFELSE(
	 [AC_LANG_PROGRAM(
	  [],
	  [asm ("setssbsy");])],
	 [],
	 [AC_MSG_ERROR([assembler with CET support is required for --enable-cet])])
	;;
    esac
    ;;
  *)
    enable_cet=no
    ;;
esac
if test x$enable_cet = xyes; then
  $1="-fcf-protection -mcet"
  AC_MSG_RESULT([yes])
else
  AC_MSG_RESULT([no])
fi
])