Re: [PATCH] -fprofile-reproducible: fix option value handling

[Sergei Trofimovich via Gcc-patches]

On Mon, 14 Sep 2020 09:34:08 +0200
Richard Biener <richard.guent...@gmail.com> wrote:

> On Fri, Sep 11, 2020 at 11:56 PM Sergei Trofimovich via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > From: Sergei Trofimovich <siarh...@google.com>
> >
> > Before the change option handling did not accept an argument:
> >   xgcc: error: unknown profile reproducibility method '=serial'
> >   xgcc: note: valid arguments to '-fprofile-reproducible' are: 
> > multithreaded parallel-runs serial; did you mean 'serial'?
> >
> > The change also includes trailing '=' as part of option prefix.  
> 
> Does it still work without an option then?

'-fprofile-reproducible' seems to be unacceptable value.

Initially when I sent the patch I though there was no way to pass
the option to gcc. But now I understand how to do it (case 4):

Before:
  1 $ gcc-11.0.0 -c -fprofile-reproducible a.c -o a
  gcc-11.0.0: error: missing argument to '-fprofile-reproducible'
  2 $ gcc-11.0.0 -c -fprofile-reproducible= a.c -o a
  gcc-11.0.0: error: unknown profile reproducibility method '='
  gcc-11.0.0: note: valid arguments to '-fprofile-reproducible' are: 
multithreaded parallel-runs serial
  3 $ gcc-11.0.0 -c -fprofile-reproducible=serial a.c -o a
  gcc-11.0.0: error: unknown profile reproducibility method '=serial'
  gcc-11.0.0: note: valid arguments to '-fprofile-reproducible' are: 
multithreaded parallel-runs serial; did you mean 'serial'?
  4 $ gcc-11.0.0 -c -fprofile-reproducibleserial a.c -o a
  # ok

Note: case 4 was a way to pass the option.

After:
  1 $ ./xgcc -B. -c -fprofile-reproducible a.c -o a.o
  xgcc: error: unrecognized command-line option '-fprofile-reproducible'; did 
you mean '-fprofile-reproducible='?
  2 $ ./xgcc -B. -c -fprofile-reproducible= a.c -o a.o
  xgcc: error: missing argument to '-fprofile-reproducible='
  3 $ ./xgcc -B. -c -fprofile-reproducible=serial a.c -o a.o
  # ok
  4 $ ./xgcc -B. -c -fprofile-reproducibleserial a.c -o a.o
  xgcc: error: unrecognized command-line option '-fprofile-reproducibleserial'; 
did you mean '-fprofile-reproducible=serial'?

Note: two problems here:
a) case 2 got worse diagnostic
b) case 4 broke something that worked before

I'll look at "a)" to check if it can be easily fixed. Is "b)" worth handling as 
well?
I'll need a hint or example how to handle an alias like that.

> OK if so.
> 
> > gcc/ChangeLog:
> >
> >         * common.opt: Fix handling of '-fprofile-reproducible' option.
> > ---
> >  gcc/common.opt | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/gcc/common.opt b/gcc/common.opt
> > index dd68c61ae1d..84bf521128d 100644
> > --- a/gcc/common.opt
> > +++ b/gcc/common.opt
> > @@ -2228,7 +2228,7 @@ Enum(profile_reproducibility) String(parallel-runs) 
> > Value(PROFILE_REPRODUCIBILIT
> >  EnumValue
> >  Enum(profile_reproducibility) String(multithreaded) 
> > Value(PROFILE_REPRODUCIBILITY_MULTITHREADED)
> >
> > -fprofile-reproducible
> > +fprofile-reproducible=
> >  Common Joined RejectNegative Var(flag_profile_reproducible) 
> > Enum(profile_reproducibility) Init(PROFILE_REPRODUCIBILITY_SERIAL)
> >  -fprofile-reproducible=[serial|parallel-runs|multithreaded]    Control 
> > level of reproducibility of profile gathered by -fprofile-generate.
> >
> > --
> > 2.28.0
> >  


-- 

  Sergei