[Bug driver/46802] New: GCC option handling change breaks dejagnu

[Bug driver/46802] New: GCC option handling change breaks dejagnu

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46802

           Summary: GCC option handling change breaks dejagnu
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: driver
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hjl.tools@gmail.com
                CC: jsm28@gcc.gnu.org


GCC 4.6 failed binutils tests:

g++: warning: switch '-fvtable-gc' is no longer supported
g++: warning: switch '-fvtable-gc' is no longer supported

ERROR: /export/gnu/import/git/binutils/ld/testsuite/ld-selective/3.cc:
compilation failed
UNRESOLVED: selective4

prune_warnings in dejagnu has

    regsub -all "(^|\n)(cc1: warning: -g is only supported when using GAS on
this processor\[^\n\]*\ncc1: warning:\[^\n\]*\n?)+" $text "\\1" text
    regsub -all "(^|\n)(cc1plus: warning: -g is only supported when using GAS
on this processor\[^\n\]*\ncc1plus: warning:\[^\n\]*\n?)+" $text "\\1" text

Before GCC 4.6, we have

[hjl@gnu-6 tmp]$ g++ -fvtable-gc -S x.i      
cc1plus: warning: switch \u2018-fvtable-gc\u2019 is no longer supported

GCC 4.6 has

[hjl@gnu-6 tmp]$ /usr/gcc-4.6/bin/g++ -fvtable-gc -S x.i    
g++: warning: switch \u2018-fvtable-gc\u2019 is no longer supported

This change breaks prune_warnings.

[Bug driver/46802] GCC option handling change breaks dejagnu

[joseph at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46802

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2010-12-04 18:44:51 UTC ---
On Sat, 4 Dec 2010, hjl.tools at gmail dot com wrote:

> g++: warning: switch '-fvtable-gc' is no longer supported
> g++: warning: switch '-fvtable-gc' is no longer supported

This is unrelated to the DejaGnu code you quote.

> prune_warnings in dejagnu has
> 
>     regsub -all "(^|\n)(cc1: warning: -g is only supported when using GAS on
> this processor\[^\n\]*\ncc1: warning:\[^\n\]*\n?)+" $text "\\1" text
>     regsub -all "(^|\n)(cc1plus: warning: -g is only supported when using GAS
> on this processor\[^\n\]*\ncc1plus: warning:\[^\n\]*\n?)+" $text "\\1" text

None of this DejaGnu code appears to do anything with -fvtable-gc 
diagnostics, unless there was a previous warning about -g that you didn't 
quote.  The ld testsuite tries to skip these tests case on the compiler 
version number - is that broken?

In any case, it's clearly better for warnings to start "g++:" instead of 
"cc1plus:".  The cc1plus binary is an internal implementation detail; 
diagnostics should refer to the user-visible binary, which is g++ here.

[Bug driver/46802] GCC option handling change breaks dejagnu

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46802

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> 2010-12-04 18:49:29 UTC ---
You can use GCC 4.6 to run "make check" in ld to see the
failures for yourselves.

I checked this patch into binutils:

http://sourceware.org/ml/binutils/2010-12/msg00189.html

to work around it.

[Bug driver/46802] GCC option handling change breaks dejagnu

[joseph at codesourcery dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46802

--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2010-12-04 18:56:17 UTC ---
This is not a GCC bug.  It is correct that the message says "g++".  (You 
have not given a convincing analysis of why it breaks anything, but the 
bug is still not in CGC.)

[Bug driver/46802] GCC option handling change breaks dejagnu

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46802

--- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> 2010-12-04 19:06:01 UTC ---
(In reply to comment #3)
> This is not a GCC bug.  It is correct that the message says "g++".  (You 
> have not given a convincing analysis of why it breaks anything, but the 
> bug is still not in CGC.)

I am not saying "g++" is incorrect. It is just that some packages
don't expect such changes in GCC warning messages. I have changed
binutils to work around it.  I don't know if it will cause troubles
for other programs.

[Bug driver/46802] GCC option handling change breaks dejagnu

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46802

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |steven at gcc dot gnu.org
         Resolution|                            |INVALID

--- Comment #5 from Steven Bosscher <steven at gcc dot gnu.org> 2010-12-04 19:36:27 UTC ---
This is not a real bug, and not even a GCC problem (I agree with Joseph that
this is actually an improvement).

But perhaps something can be said about this in the gcc-4.6 release notes.