From: "Joseph S. Myers" <joseph@codesourcery.com>
To: Sylvestre Ledru <sylvestre@debian.org>
Cc: <gcc-patches@gcc.gnu.org>, Jason Merrill <jason@redhat.com>
Subject: Re: [Patch] PR55189 enable -Wreturn-type by default
Date: Thu, 05 Jun 2014 18:01:00 -0000 [thread overview]
Message-ID: <Pine.LNX.4.64.1406051749260.2819@digraph.polyomino.org.uk> (raw)
In-Reply-To: <53903961.9030501@debian.org>
On Thu, 5 Jun 2014, Sylvestre Ledru wrote:
> > Some of those patches appear to be addressing cases where control appears
> > to reach the end of a function returning non-void, as opposed to cases
> > where the return type defaults to int.
> Do you have an example of the patches you are talking about?
In 0004-Update-gcc-tests-with-warning-return-type-enabled-by.patch the
very first change is adding such a "return 0;" (as are lots of others).
> You are talking about code like this one (from Jonathan Wakely) ?
>
> int f(int c)
> {
> if (c)
> return 0;
> function_that_never_returns();
> }
Yes.
> Initially, I implemented -Wmissing-return to manage this case (
> https://gcc.gnu.org/ml/gcc-patches/2014-01/msg00820.html ) but Jason
> suggested to remove that:
> https://gcc.gnu.org/ml/gcc-patches/2014-01/msg01033.html
> (I don't have a strong opinion on the subject).
I think splitting the option like that makes sense. Compatibility
indicates that -Wreturn-type and -Wall should still enable
-Wmissing-return, but only the other pieces of -Wreturn-type should be
enabled by default, at least for C. (Enabling -Wimplicit-int by default
might be a good starting point.)
Also, at least one testsuite change in your patch is wrong. You add an
"int" return type to c90-impl-int-1.c, which is explicitly checking the
implicit int functionality for C90; use of dg-warning there would be more
appropriate (since the point is that it doesn't give an error with
-pedantic-errors). It would probably also be best not to add
-Wno-return-type in c99-impl-int-1.c. (Any places where /* { dg-bogus
"warning" "warning in place of error" } */ in tests causes problems
because you get a new warning *in addition* to the existing error can have
that dg-bogus removed and a dg-warning directive for the warning added -
dg-warning/dg-error used not to distinguish properly between warnings and
errors, so requiring such dg-bogus directives if you wanted to test the
difference, but that was fixed a long time ago.)
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2014-06-05 18:01 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-04 19:49 Sylvestre Ledru
2014-06-04 22:35 ` Mike Stump
2014-06-04 23:31 ` Joseph S. Myers
2014-06-05 9:33 ` Sylvestre Ledru
2014-06-05 18:01 ` Joseph S. Myers [this message]
2014-06-17 16:52 ` Sylvestre Ledru
2014-06-17 17:15 ` Joseph S. Myers
2014-06-17 17:37 ` Sylvestre Ledru
2014-06-17 17:41 ` Joseph S. Myers
2014-07-07 17:18 ` Sylvestre Ledru
2014-07-20 19:20 ` Sylvestre Ledru
2014-07-30 22:10 ` Joseph S. Myers
2014-08-11 7:44 ` Sylvestre Ledru
2014-08-12 17:49 ` Joseph S. Myers
2014-08-12 17:53 ` Sylvestre Ledru
2014-08-14 17:01 ` Sylvestre Ledru
-- strict thread matches above, loose matches on Subject: below --
2014-08-14 18:49 Manuel López-Ibáñez
2014-08-15 16:28 ` Sylvestre Ledru
2014-08-19 22:03 ` Joseph S. Myers
2014-08-20 21:42 ` Sylvestre Ledru
2014-08-20 21:58 ` Joseph S. Myers
2013-12-20 17:54 Sylvestre Ledru
2013-12-27 5:26 ` Chung-Ju Wu
2013-12-27 5:32 ` Yury Gribov
2014-01-14 17:49 ` Sylvestre Ledru
2014-01-16 19:44 ` Jason Merrill
2014-01-23 6:44 ` Sylvestre Ledru
2014-01-23 18:48 ` Jason Merrill
2014-01-23 18:57 ` Sylvestre Ledru
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