[v3] elf: Silence GCC 11/12 false positive warning
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dj/TryBot-apply_patch |
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Patch applied to master at the time it was sent
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dj/TryBot-32bit |
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Build for i686
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Commit Message
Silence GCC 11/12 false positive warning with -mavx512f on dl-load.c:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106008
$ gcc -O2 -fPIC -march=x86-64 -mavx512f -S -Wall ...
dl-load.c: In function ‘_dl_map_object_from_fd.constprop’:
dl-load.c:1158:30: warning: ‘(((char *)loadcmds.113_68 + _933 + 16))[329406144173384849].mapend’ may be used uninitialized [-Wmaybe-uninitialized]
---
elf/dl-load.c | 9 +++++++++
1 file changed, 9 insertions(+)
Comments
* H. J. Lu via Libc-alpha:
> Silence GCC 11/12 false positive warning with -mavx512f on dl-load.c:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106008
>
> $ gcc -O2 -fPIC -march=x86-64 -mavx512f -S -Wall ...
> dl-load.c: In function ‘_dl_map_object_from_fd.constprop’:
> dl-load.c:1158:30: warning: ‘(((char *)loadcmds.113_68 + _933 + 16))[329406144173384849].mapend’ may be used uninitialized [-Wmaybe-uninitialized]
> ---
> elf/dl-load.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index 2e4a010fc5..400b2b8d7b 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c
> @@ -1152,10 +1152,19 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
> p_align_max = ph->p_align;
> c->mapoff = ALIGN_DOWN (ph->p_offset, GLRO(dl_pagesize));
>
> + DIAG_PUSH_NEEDS_COMMENT;
> +
> +#if __GNUC_PREREQ (11, 0)
> + /* Suppress valid GCC warning:
> + ‘(((char *)loadcmds.113_68 + _933 + 16))[329406144173384849].mapend’ may be used uninitialized [-Wmaybe-uninitialized]
> + */
> + DIAG_IGNORE_NEEDS_COMMENT (11, "-Wmaybe-uninitialized");
> +#endif
> /* Determine whether there is a gap between the last segment
> and this one. */
> if (nloadcmds > 1 && c[-1].mapend != c->mapstart)
> has_holes = true;
> + DIAG_POP_NEEDS_COMMENT;
The commit message says “false positive”, the comment says “valid GCC
warning”. The comment should mention the PR number, too.
Thanks,
Florian
@@ -1152,10 +1152,19 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
p_align_max = ph->p_align;
c->mapoff = ALIGN_DOWN (ph->p_offset, GLRO(dl_pagesize));
+ DIAG_PUSH_NEEDS_COMMENT;
+
+#if __GNUC_PREREQ (11, 0)
+ /* Suppress valid GCC warning:
+ ‘(((char *)loadcmds.113_68 + _933 + 16))[329406144173384849].mapend’ may be used uninitialized [-Wmaybe-uninitialized]
+ */
+ DIAG_IGNORE_NEEDS_COMMENT (11, "-Wmaybe-uninitialized");
+#endif
/* Determine whether there is a gap between the last segment
and this one. */
if (nloadcmds > 1 && c[-1].mapend != c->mapstart)
has_holes = true;
+ DIAG_POP_NEEDS_COMMENT;
/* Optimize a common case. */
#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7