From: Simon Marchi <simark@simark.ca>
To: Mark Wielaard <mark@klomp.org>, gdb-patches@sourceware.org
Subject: Re: [PATCH] xcoffread.c: Fix -Werror=dangling-pointer= issue with main_subfile.
Date: Mon, 1 May 2023 09:53:39 -0400 [thread overview]
Message-ID: <fae5cf54-179b-a078-b3c5-a93789cead56@simark.ca> (raw)
In-Reply-To: <20230429211342.1369527-1-mark@klomp.org>
On 4/29/23 17:13, Mark Wielaard wrote:
> GCC 13 points out that main_subfile has local function scope, but a
> pointer to it is assigned to the global inclTable array subfile
> element field:
>
> In function ‘void process_linenos(CORE_ADDR, CORE_ADDR)’,
> inlined from ‘void aix_process_linenos(objfile*)’ at xcoffread.c:727:19,
> inlined from ‘void aix_process_linenos(objfile*)’ at xcoffread.c:720:1:
> xcoffread.c:629:37: error: storing the address of local variable ‘main_subfile’ in ‘*inclTable.19_45 + _28._inclTable::subfile’ [-Werror=dangling-pointer=]
> 629 | inclTable[ii].subfile = &main_subfile;
> | ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
> xcoffread.c: In function ‘void aix_process_linenos(objfile*)’:
> xcoffread.c:579:18: note: ‘main_subfile’ declared here
> 579 | struct subfile main_subfile;
> | ^~~~~~~~~~~~
> xcoffread.c:496:19: note: ‘inclTable’ declared here
> 496 | static InclTable *inclTable; /* global include table */
> | ^~~~~~~~~
>
> Fix this by making main_subfile file static that is allocated and
> deallocated together with inclTable and allocate_include_entry and
> xcoff_symfile_finish. Adjust the use of main_subfile in
> process_linenos to take a pointer to the struct subfile.
I'm not familiar at all with this code, but your change looks reasonable
to me.
Some style comments:
> ---
> gdb/xcoffread.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/gdb/xcoffread.c b/gdb/xcoffread.c
> index d71127b40f6..db6f2df6c0a 100644
> --- a/gdb/xcoffread.c
> +++ b/gdb/xcoffread.c
> @@ -498,6 +498,9 @@ static int inclIndx; /* last entry to table */
> static int inclLength; /* table length */
> static int inclDepth; /* nested include depth */
>
> +/* subfile structure for the main compilation unit. */
> +static struct subfile *main_subfile;
Remove "struct".
> @@ -548,6 +551,7 @@ allocate_include_entry (void)
> inclTable = XCNEWVEC (InclTable, INITIAL_INCLUDE_TABLE_LENGTH);
> inclLength = INITIAL_INCLUDE_TABLE_LENGTH;
> inclIndx = 0;
> + main_subfile = new (struct subfile);
"new subfile" would be enough.
> for (int ii = 0; ii < inclIndx; ++ii)
> {
> - if (inclTable[ii].subfile != ((struct subfile *) &main_subfile)
> + if (inclTable[ii].subfile != ((struct subfile *) main_subfile)
Since you touch this line, I think you could remove the cast.
main_subfile is already of the right type.
Simon
next prev parent reply other threads:[~2023-05-01 13:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-29 21:13 Mark Wielaard
2023-05-01 13:53 ` Simon Marchi [this message]
2023-05-01 18:14 ` Mark Wielaard
2023-05-01 18:19 ` [PATCHv2] " Mark Wielaard
2023-05-02 15:12 ` Tom Tromey
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=fae5cf54-179b-a078-b3c5-a93789cead56@simark.ca \
--to=simark@simark.ca \
--cc=gdb-patches@sourceware.org \
--cc=mark@klomp.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).