From: Richard Biener <richard.guenther@gmail.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: "Joseph S. Myers" <joseph@codesourcery.com>,
Marek Polacek <polacek@redhat.com>,
Jason Merrill <jason@redhat.com>, Jan Hubicka <hubicka@ucw.cz>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [C PATCH] Fix -Wunused-function (PR debug/66869)
Date: Tue, 26 Jan 2016 15:21:00 -0000 [thread overview]
Message-ID: <CAFiYyc12VJd=HcmH6YsnwVWinfzBnMzq-WyujU85eg05LCUReg@mail.gmail.com> (raw)
In-Reply-To: <20160125203829.GP3017@tucnak.redhat.com>
On Mon, Jan 25, 2016 at 9:38 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> The early-debug changes moved warnings about unused functions into cgraph.
> The problem is that if we have just unused declarations, they aren't
> sometimes even registered with cgraph and therefore we no longer warn.
>
> Here is an attempt to register those with cgraph anyway to get the warning,
> for C FE only (no idea where to do that in C++ FE). Or anyone has better
> suggestions what to do?
>
> Bootstrapped/regtested on x86_64-linux and i686-linux.
>
> 2016-01-25 Jakub Jelinek <jakub@redhat.com>
>
> PR debug/66869
> * c-decl.c (c_write_global_declarations_1): For warn_unused_function,
> ensure creation of cgraph node even if there is no definition.
>
> * gcc.dg/pr66869.c: New test.
>
> --- gcc/c/c-decl.c.jj 2016-01-21 00:41:47.000000000 +0100
> +++ gcc/c/c-decl.c 2016-01-25 16:36:31.973504082 +0100
> @@ -10741,11 +10741,19 @@ c_write_global_declarations_1 (tree glob
> if (TREE_CODE (decl) == FUNCTION_DECL
> && DECL_INITIAL (decl) == 0
> && DECL_EXTERNAL (decl)
> - && !TREE_PUBLIC (decl)
> - && C_DECL_USED (decl))
> + && !TREE_PUBLIC (decl))
> {
> - pedwarn (input_location, 0, "%q+F used but never defined", decl);
> - TREE_NO_WARNING (decl) = 1;
> + if (C_DECL_USED (decl))
> + {
> + pedwarn (input_location, 0, "%q+F used but never defined", decl);
> + TREE_NO_WARNING (decl) = 1;
> + }
> + /* For -Wunused-function push the unused statics into cgraph,
> + so that check_global_declaration emits the warning. */
> + else if (warn_unused_function
> + && ! DECL_ARTIFICIAL (decl)
> + && ! TREE_NO_WARNING (decl))
> + cgraph_node::get_create (decl);
Err, so why not warn here directly?
Richard.
> }
>
> wrapup_global_declaration_1 (decl);
> --- gcc/testsuite/gcc.dg/pr66869.c.jj 2016-01-25 16:38:39.037758657 +0100
> +++ gcc/testsuite/gcc.dg/pr66869.c 2016-01-25 16:39:42.346888954 +0100
> @@ -0,0 +1,6 @@
> +/* PR debug/66869 */
> +/* { dg-do compile } */
> +/* { dg-options "-Wunused-function" } */
> +
> +static void test (void); /* { dg-warning "'test' declared 'static' but never defined" } */
> +int i;
>
> Jakub
next prev parent reply other threads:[~2016-01-26 15:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-25 20:38 Jakub Jelinek
2016-01-26 15:21 ` Richard Biener [this message]
2016-01-26 16:18 ` Jakub Jelinek
2016-01-27 10:17 ` Richard Biener
2016-01-27 18:52 ` Jakub Jelinek
2016-01-27 19:29 ` Jeff Law
2016-01-28 20:15 ` [C++ " Jakub Jelinek
2016-01-29 10:25 ` Jason Merrill
2016-01-29 10:35 ` Jakub Jelinek
2016-01-29 10:47 ` Jason Merrill
2016-01-29 12:31 ` Jakub Jelinek
2016-02-03 16:05 ` Jason Merrill
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