Re: [PATCH] target: missing -Whardened with -fcf-protection=none [PR114606]

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Apr 05, 2024 at 02:22:18PM -0400, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> 
> -- >8 --
> -Whardened warns when -fhardened couldn't enable a hardening option
> because that option was disabled on the command line, e.g.:
> 
> $ ./cc1plus -quiet g.C -fhardened -O2 -fstack-protector
> cc1plus: warning: '-fstack-protector-strong' is not enabled by '-fhardened' because it was specified on the command line [-Whardened]
> 
> but it doesn't work as expected with -fcf-protection=none:
> 
> $ ./cc1plus -quiet g.C -fhardened -O2 -fcf-protection=none
> 
> because we're checking == CF_NONE which doesn't distinguish between nothing
> and -fcf-protection=none.  I should have used OPTION_SET_P, like below.
> 
> 	PR target/114606
> 
> gcc/ChangeLog:
> 
> 	* config/i386/i386-options.cc (ix86_option_override_internal): Use
> 	OPTION_SET_P rather than checking == CF_NONE.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/i386/fhardened-1.c: New test.
> 	* gcc.target/i386/fhardened-2.c: New test.
> ---
>  gcc/config/i386/i386-options.cc             | 2 +-
>  gcc/testsuite/gcc.target/i386/fhardened-1.c | 8 ++++++++
>  gcc/testsuite/gcc.target/i386/fhardened-2.c | 8 ++++++++
>  3 files changed, 17 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/fhardened-1.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/fhardened-2.c
> 
> diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
> index 7896d576977..20c6dc48090 100644
> --- a/gcc/config/i386/i386-options.cc
> +++ b/gcc/config/i386/i386-options.cc
> @@ -3242,7 +3242,7 @@ ix86_option_override_internal (bool main_args_p,
>       on the command line.  */
>    if (opts->x_flag_hardened && cf_okay_p)
>      {
> -      if (opts->x_flag_cf_protection == CF_NONE)
> +      if (!OPTION_SET_P (flag_cf_protection))

This function is passed explicit opts and opts_set arguments, so it
shouldn't be using flag_something macros nor OPTION_SET_P, as the former
use global_options.x_flag_something rather than opts->x_flag_something
and the latter uses global_options_set.x_flag_something.

So, I think you want to use if (!opts_set->x_flag_cf_protection)
instead.

>  	opts->x_flag_cf_protection = CF_FULL;
>        else if (opts->x_flag_cf_protection != CF_FULL)
>  	warning_at (UNKNOWN_LOCATION, OPT_Whardened,

Otherwise LGTM.

	Jakub