Re: dg-options after board/cflags

[H.J. Lu]

On Wed, Sep 2, 2020 at 8:31 AM Jose E. Marchesi via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
>
> Hi people!
>
> While adding a bpf-sim.exp to dejagnu, I noticed that the flags in
> board/cflags were included in the final compilation line _after_ the
> flags in the test's dg-options.
>
> Since the test options are more particular than the board options, I
> would expect them to be placed after any board-defined flags, so I
> prepared the patch below for dejagnu, which does the right thing for the
> gcc.target/bpf testsuite.
>
> However:
>
> 1. There could be tests around that depend (erroneously) on some of
>    their dg-options to not have effect (or a different effect) because
>    they are annulled (or modified) by some flag in a board file.
>
> 2. This could also impact other programs using dejagnu.
>
> How do you people recommend to proceed?
> Should we fix dejagnu and then fix buggy tests?
> Or the other way around?  :-)
>
> diff --git a/lib/target.exp b/lib/target.exp
> index 36ae639..f0bfe20 100644
> --- a/lib/target.exp
> +++ b/lib/target.exp
> @@ -455,7 +455,7 @@ proc default_target_compile {source destfile type 
> options} {
>         }
>         if {[regexp "^additional_flags=" $i]} {
>             regsub "^additional_flags=" $i "" tmp
> -           append add_flags " $tmp"
> +           append additional_flags " $tmp"
>         }
>         if {[regexp "^ldflags=" $i]} {
>             regsub "^ldflags=" $i "" tmp
> @@ -703,6 +703,8 @@ proc default_target_compile {source destfile type 
> options} {
>         }
>      }
>
> +    append add_flags " $additional_flags"
> +
>      verbose "doing compile"
>
>      set sources ""
> @@ -728,7 +730,7 @@ proc default_target_compile {source destfile type 
> options} {
>             append add_flags " -o $destfile"
>         }
>      }
> -
> +
>      # This is obscure: we put SOURCES at the end when building an
>      # object, because otherwise, in some situations, libtool will
>      # become confused about the name of the actual source file.

Does your dejagnu contain

commit 5256bd82343000c76bc0e48139003f90b6184347
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Feb 26 17:53:48 2015 +1100

            * lib/target.exp (default_target_compile): Prepend multilib_flags,
            instead of appending it.

    Some GCC testcases need explicit GCC options to properly run. For
    example gcc.target/i386/pr32219-1.c has -fpie specified explicitly:

    /* { dg-options "-O2 -fpie" } */

    But with multlib, eg:
    make check-gcc RUNTESTFLAGS="--target_board='unix{-fpic}'"

    -fpic is appended to the command line options, which overrides the command
    line options specified by dg-options.  multlib flags should be placed at
    the beginning of the command line options, not at the end.  This patch
    updates default_target_compile to prepend multilib_flags, instead of
    appending it.


-- 
H.J.