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Re: [C/C++ PATCH] Reject __builtin_{add,sub,mul}_overflow with pointer to const integer as last arg (PR c/90628)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Jason Merrill <jason at redhat dot com>
- Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, Marek Polacek <polacek at redhat dot com>, Nathan Sidwell <nathan at acm dot org>, gcc-patches at gcc dot gnu dot org
- Date: Tue, 28 May 2019 15:11:11 +0200
- Subject: Re: [C/C++ PATCH] Reject __builtin_{add,sub,mul}_overflow with pointer to const integer as last arg (PR c/90628)
- References: <20190527212014.GB19695@tucnak> <78fff901-5d26-8780-cb0b-6fc0d9404530@redhat.com>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Tue, May 28, 2019 at 08:59:57AM -0400, Jason Merrill wrote:
> On 5/27/19 5:20 PM, Jakub Jelinek wrote:
> > As the testcase shows, we are silently accepting writes into const
> > variables, because the type generic builtins don't have a prototype.
> >
> > Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> > trunk?
> >
> > 2019-05-27 Jakub Jelinek <jakub@redhat.com>
> >
> > PR c/90628
> > * c-common.c (check_builtin_function_arguments)
> > <case BUILTIN_*_OVERFLOW>: Diagnose pointer to const qualified integer
> > as last argument.
> >
> > * c-c++-common/builtin-arith-overflow-3.c: New test.
> >
> > --- gcc/c-family/c-common.c.jj 2019-05-21 16:16:48.068973678 +0200
> > +++ gcc/c-family/c-common.c 2019-05-27 10:46:25.525968739 +0200
> > @@ -5995,6 +5995,13 @@ check_builtin_function_arguments (locati
> > "has pointer to boolean type", fndecl);
> > return false;
> > }
> > + else if (TYPE_READONLY (TREE_TYPE (TREE_TYPE (args[2]))))
> > + {
> > + error_at (ARG_LOCATION (2), "argument 3 in call to function %qE "
> > + "has pointer type to %<const%> qualified integer",
> > + fndecl);
>
> Is there a reason not to also print the type with %qT?
So like:
+ error_at (ARG_LOCATION (2), "argument 3 in call to function %qE "
+ "has pointer type to %<const%> qualified integer "
+ "(%qT)", fndecl, TREE_TYPE (args[2]));
or some other wording?
I didn't want to say
"argument 3 in call to function %qE has type %qT" because then
users wouldn't know what the actual problem is.
Jakub