[PATCH v3] remove attribute access from regexec

[Martin Sebor]

On 8/27/21 2:52 AM, Paul Eggert wrote:
> On 8/26/21 9:47 AM, Martin Sebor wrote:
>> I think I'd prefer to let you do this.
> 
> OK, proposed glibc patch attached. As I lack the time to shepherd each 
> regex fix into Glibc separately, I simply copied regex-relevant source 
> files from Gnulib to Glibc, after merging recent Glibc changes (plus 
> your proposal) into Gnulib.
> 
> Please give the patch a try.

The patch compiles fine with the latest GCC trunk (12.0) but it
seems to cause failures in the conformance tests that I don't think
were there before:

FAIL: conform/POSIX/regex.h/conform
FAIL: conform/POSIX2008/regex.h/conform
FAIL: conform/UNIX98/regex.h/conform
FAIL: conform/XOPEN2K/regex.h/conform
FAIL: conform/XOPEN2K8/regex.h/conform
FAIL: conform/XPG4/regex.h/conform
FAIL: conform/XPG42/regex.h/conform

The first one fails because of this (I suspect the others are
the same):

     Namespace violation: "GCC"
     Namespace violation: "diagnostic"
     Namespace violation: "ignored"
     Namespace violation: "pop"
     Namespace violation: "pragma"
     Namespace violation: "push"
FAIL: Namespace of <regex.h>

I'm guessing it's due to a limitation of the conformance test script
that considers the GCC diagnostic pragmas unsafe to use because they
are in the user-namespace (even though they're not subject to macro
expansion).  I'm still not sure I understand why the #pragma is
needed since -Wvla shouldn't trigger in a system header.

Beyond that I only skimmed your patch.  It includes quite a few
changes that don't seem necessary to avoid the GCC warning (BZ #28170)
and that I wouldn't be comfortable making at the same time.  This is
not an objection, just an explanation why I was reluctant to accept
some of your suggestions.

But just to clarify, I meant I would have preferred to just fix
the Glibc warning and let you change the other Glibc internal APIs
and handle the Gnulib integration.  Looks like you decided against
the former in the end but thanks for taking care of the latter.

Martin