GNU bug report logs - #51172
Fix null-dereference warnings when compiling Emacs with GCC

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Emacs bug reports <bug-gnu-emacs <at> gnu.org>
Subject: Fix null-dereference warnings when compiling Emacs with GCC
Date: Tue, 12 Oct 2021 17:34:11 -0700

[Message part 1 (text/plain, inline)]

The attached patch against emacs-28 suppresses the final remaining GCC 
11.2.1 diagnostics that are emitted after emacs-28 is configured with 
--enable-gcc-warnings on x86-64.

The patch is benign, and it's conceivable that changing xmalloc etc. to 
always return nonnull fixes unlikely and obscure bugs (though I haven't 
checked this). However, I didn't install the patch into the emacs-28 
branch on the off-chance that Eli would prefer this sort of thing to be 
installed into the master branch.

[0001-Pacify-GCC-Wanalyzer-possible-null-dereference.patch (text/x-patch, attachment)]

Message #10 received at 51172 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 51172 <at> debbugs.gnu.org
Subject: Re: bug#51172: Fix null-dereference warnings when compiling Emacs
 with GCC
Date: Wed, 13 Oct 2021 15:14:34 +0300

> Date: Tue, 12 Oct 2021 17:34:11 -0700
> From: Paul Eggert <eggert <at> cs.ucla.edu>
> 
> The attached patch against emacs-28 suppresses the final remaining GCC 
> 11.2.1 diagnostics that are emitted after emacs-28 is configured with 
> --enable-gcc-warnings on x86-64.
> 
> The patch is benign, and it's conceivable that changing xmalloc etc. to 
> always return nonnull fixes unlikely and obscure bugs (though I haven't 
> checked this). However, I didn't install the patch into the emacs-28 
> branch on the off-chance that Eli would prefer this sort of thing to be 
> installed into the master branch.

Yes, please install on master.  We don't expect users to configure the
released Emacs with --enable-gcc-warnings, and the changes are
non-trivial.

> -  /* We must call malloc explicitly when BLOCK is 0, since some
> -     reallocs don't do this.  */
> +  /* Call malloc when BLOCK is null,
> +     since lrealloc does not allow a null BLOCK.  */

Typo in this comment: "malloc" should be "lmalloc".

Thanks.

Message #15 received at 51172-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 51172-done <at> debbugs.gnu.org
Subject: Re: bug#51172: Fix null-dereference warnings when compiling Emacs
 with GCC
Date: Wed, 13 Oct 2021 11:49:38 -0700

On 10/13/21 5:14 AM, Eli Zaretskii wrote:

> Yes, please install on master.

Thanks, done, and closing the bug report. I also got another diagnostic 
in the master branch, and fixed that in a separate commit.

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