Re: dg-options after board/cflags

[Jose E. Marchesi]

> 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.

Yeah, this is dejagnu master.

Your patch dealt with board/multilib_flags, but the same problem exists
for board/cflags and many other flag-containing options.