From: Kriang Lerdsuwanakij <lerdsuwa@scf-fs.usc.edu>
To: egcs@cygnus.com
Subject: Re: Bug in coerce_template_parms (patch)
Date: Tue, 17 Mar 1998 01:53:00 -0000 [thread overview]
Message-ID: <350E4711.605E@scf.usc.edu> (raw)
Sorry, the previous patch is broken... I'll look at that again
tomorrow.
Kriang
Kriang Lerdsuwanakij wrote:
>
> Martin von Loewis wrote:
> >
> > Did anybody notice problems in template parameter resolution?
> > There seems to be a problem in coerce_template_parms, exposed e.g.
> > by ttp26.C. Around line 1896, it checks whether the arglist is
> > a vector. If it isn't, it treats it as a list.
> >
> > Now, there is another check whether nargs==nparms. In ttp26.C, this is
> > not the case because there are default parameters. So the check
> > fails, but the arguments are still passed as a vector. This goes
> > unnoticed, as the code retrieves the argument using TREE_VALUE, which
> > happens to be the right offset. I'm sure one can construct examples
> > where the code breaks, though.
> >
>
> > I found this by putting an assertion into TREE_VALUE that the node
> > really is a TREE_LIST. I don't have a test case for this specific
> > code. If nobody can reproduce the problem, I can try to find one. For
> > ttp26.C, the problem manifests in the 20th invocation of
> > coerce_template_parms.
> >
> > Thanks,
> > Martin
>
> Thanks for pointing that out. It's a bug (and my fault :( ). Below is
> a small patch that fixes that. When arglist is a vector with less
> elements than required, it should be handled by inside the
> 'else if (is_tmpl_parm && i < nargs)' case. is_tmpl_parm is an
> indicator that vector may not satisfy the nargs==nparms condition.
>
> Kriang
>
> ===========================
>
> * pt.c (coerce_template_parms): Fix thinko.
>
> *** pt.c 1998/03/10 10:01:37 1.6
> --- pt.c 1998/03/17 04:21:51
> *************** coerce_template_parms (parms, arglist, i
> *** 1904,1910 ****
> tree arg;
> tree parm = TREE_VEC_ELT (parms, i);
>
> ! if (arglist)
> {
> arg = arglist;
> arglist = TREE_CHAIN (arglist);
> --- 1904,1910 ----
> tree arg;
> tree parm = TREE_VEC_ELT (parms, i);
>
> ! if (arglist && TREE_CODE (arglist) == TREE_LIST)
> {
> arg = arglist;
> arglist = TREE_CHAIN (arglist);
next reply other threads:[~1998-03-17 1:53 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-03-17 1:53 Kriang Lerdsuwanakij [this message]
-- strict thread matches above, loose matches on Subject: below --
1998-03-15 15:15 Bug in coerce_template_parms Martin von Loewis
1998-03-16 20:44 ` Bug in coerce_template_parms (patch) Kriang Lerdsuwanakij
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