On Wed, Aug 26, 2020 at 10:13 AM Martin Liška <mli...@suse.cz> wrote:
>
> Hey.
>
> We should document how we currently merge pie and pie options
> as we fixed PR80838.
>
> Ready for master?
OK.
> Thanks,
> Martin
>
> gcc/ChangeLog:
>
> * doc/invoke.texi: Document how are pie and pic options merged.
> ---
> gcc/doc/invoke.texi | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 4cf6b204b56..95d3699d1fa 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -11569,9 +11569,20 @@ There are some code generation flags preserved by
> GCC when
> generating bytecodes, as they need to be used during the final link.
> Currently, the following options and their settings are taken from
> the first object file that explicitly specifies them:
> -@option{-fPIC}, @option{-fpic}, @option{-fpie}, @option{-fcommon},
> -@option{-fexceptions}, @option{-fnon-call-exceptions}, @option{-fgnu-tm}
> -and all the @option{-m} target flags.
> +@option{-fcommon}, @option{-fexceptions}, @option{-fnon-call-exceptions},
> +@option{-fgnu-tm} and all the @option{-m} target flags.
> +
> +The following options @option{-fPIC}, @option{-fpic}, @option{-fpie} and
> +@option{-fPIE} are combined based on the following scheme:
> +
> +@smallexample
> +@option{-fPIC} + @option{-fpic} = @option{-fpic}
> +@option{-fPIC} + @option{-fno-pic} = @option{-fno-pic}
> +@option{-fpic/-fPIC} + (no option) = (no option)
> +@option{-fPIC} + @option{-fPIE} = @option{-fPIE}
> +@option{-fpic} + @option{-fPIE} = @option{-fpie}
> +@option{-fPIC/-fpic} + @option{-fpie} = @option{-fpie}
> +@end smallexample
>
> Certain ABI-changing flags are required to match in all compilation units,
> and trying to override this at link time with a conflicting value
> --
> 2.28.0
>
