On Fri, May 12, 2023 at 10:54 PM Jason Merrill via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> In the context of the recent discussion, it occurred to me that this semantic
> would be useful, but currently there is no easy way to access it.
> Bikeshedding
> welcome; the use of this flag is a bit odd, but it has the advantage of being
> accepted without error going back at least to 4.3.
>
> -- 8< --
>
> Currently there is no flag to use to upgrade all currently-enabled pedwarns
> from warning to error. -pedantic-errors also enables the -Wpedantic
> pedwarns, while -Werror=pedantic uselessly makes only the -Wpedantic
> pedwarns errors.
>
> I suggest that since -fpermissive lowers some diagnostics from error to
> warning, -fno-permissive could do the reverse.
Hmm, but that makes '-fno-permissive' different from '-fpermissive
-fno-permissive'?
What about '-fpermissive -fno-permissive -fno-permissive' then?
So I think over-loading -fno-permissive with differen semantics from negating
the option is bad.
Richard.
>
> gcc/ChangeLog:
>
> * doc/invoke.texi: Document -fno-permissive.
>
> gcc/c-family/ChangeLog:
>
> * c.opt (fpermissive): Accept in C and ObjC as well.
> * c-opts.cc (c_common_post_options): -fno-permissive sets
> global_dc->pedantic_errors.
> ---
> gcc/doc/invoke.texi | 7 +++++++
> gcc/c-family/c.opt | 2 +-
> gcc/c-family/c-opts.cc | 4 ++++
> 3 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index b92b8576027..6198df14382 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -3438,11 +3438,18 @@ issue. Currently, the only such diagnostic issued by
> G++ is the one for
> a name having multiple meanings within a class.
>
> @opindex fpermissive
> +@opindex fno-permissive
> @item -fpermissive
> Downgrade some diagnostics about nonconformant code from errors to
> warnings. Thus, using @option{-fpermissive} allows some
> nonconforming code to compile.
>
> +Conversely, @option{-fno-permissive} can be used to upgrade some
> +diagnostics about nonconformant code from warnings to errors. This
> +differs from @option{-pedantic-errors} in that the latter also implies
> +@option{-Wpedantic}; this option does not enable additional
> +diagnostics, only upgrades the severity of those that are enabled.
> +
> @opindex fno-pretty-templates
> @opindex fpretty-templates
> @item -fno-pretty-templates
> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> index 3333cddeece..07165d2bbe8 100644
> --- a/gcc/c-family/c.opt
> +++ b/gcc/c-family/c.opt
> @@ -2075,7 +2075,7 @@ C ObjC C++ ObjC++
> Look for and use PCH files even when preprocessing.
>
> fpermissive
> -C++ ObjC++ Var(flag_permissive)
> +C ObjC C++ ObjC++ Var(flag_permissive)
> Downgrade conformance errors to warnings.
>
> fplan9-extensions
> diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc
> index c68a2a27469..1973c068d59 100644
> --- a/gcc/c-family/c-opts.cc
> +++ b/gcc/c-family/c-opts.cc
> @@ -1021,6 +1021,10 @@ c_common_post_options (const char **pfilename)
> SET_OPTION_IF_UNSET (&global_options, &global_options_set,
> flag_delete_dead_exceptions, true);
>
> + if (!global_options_set.x_flag_pedantic_errors
> + && global_options_set.x_flag_permissive)
> + global_dc->pedantic_errors = !flag_permissive;
> +
> if (cxx_dialect >= cxx11)
> {
> /* If we're allowing C++0x constructs, don't warn about C++98
>
> base-commit: 62c4d34ec005e95f000ffabd34da440dc62ac346
> --
> 2.31.1
>
