[3/3] locale: prevent maybe-uninitialized errors with -Os [BZ #19444]
Commit Message
Fixes following error when building for aarch64 with -Os:
| In file included from strcoll_l.c:43:
| strcoll_l.c: In function '__strcoll_l':
| ../locale/weight.h:31:26: error: 'seq2.back_us' may be used uninitialized in this function [-Werror=maybe-uninitialized]
| int_fast32_t i = table[*(*cpp)++];
| ^~~~~~~~~
| strcoll_l.c:304:18: note: 'seq2.back_us' was declared here
| coll_seq seq1, seq2;
| ^~~~
| In file included from strcoll_l.c:43:
| ../locale/weight.h:31:26: error: 'seq1.back_us' may be used uninitialized in this function [-Werror=maybe-uninitialized]
| int_fast32_t i = table[*(*cpp)++];
| ^~~~~~~~~
| strcoll_l.c:304:12: note: 'seq1.back_us' was declared here
| coll_seq seq1, seq2;
| ^~~~
Partial fix for [BZ #23716]
* locale/weight.h: Fix build with -Os.
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
---
ChangeLog | 4 ++++
locale/weight.h | 7 +++++++
2 files changed, 11 insertions(+)
Comments
On Sun, Sep 30, 2018 at 03:53:55PM +0000, Martin Jansa wrote:
> Fixes following error when building for aarch64 with -Os:
> | In file included from strcoll_l.c:43:
> | strcoll_l.c: In function '__strcoll_l':
> | ../locale/weight.h:31:26: error: 'seq2.back_us' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> | int_fast32_t i = table[*(*cpp)++];
> | ^~~~~~~~~
> | strcoll_l.c:304:18: note: 'seq2.back_us' was declared here
> | coll_seq seq1, seq2;
> | ^~~~
> | In file included from strcoll_l.c:43:
> | ../locale/weight.h:31:26: error: 'seq1.back_us' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> | int_fast32_t i = table[*(*cpp)++];
> | ^~~~~~~~~
> | strcoll_l.c:304:12: note: 'seq1.back_us' was declared here
> | coll_seq seq1, seq2;
> | ^~~~
>
> Partial fix for [BZ #23716]
> * locale/weight.h: Fix build with -Os.
>
> Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
I'm sorry for delay, I've just sent v6 for the first patch in this
series:
[PATCH 1/3] sysdeps/ieee754: prevent maybe-uninitialized errors
the 2nd one:
[PATCH 2/3] soft-fp: ignore maybe-uninitialized
was already merged, but I haven't noticed any feedback on this 3rd one
and it's still applicable in latest master.
Regards,
> ---
> ChangeLog | 4 ++++
> locale/weight.h | 7 +++++++
> 2 files changed, 11 insertions(+)
>
> diff --git a/ChangeLog b/ChangeLog
> index 9cdf59c9ab..ef506309aa 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,7 @@
> +2018-09-30 Martin Jansa <Martin.Jansa@gmail.com>
> + Partial fix for [BZ #23716]
> + * locale/weight.h: Fix build with -Os.
> +
> 2018-09-30 Martin Jansa <Martin.Jansa@gmail.com>
> Partial fix for [BZ #23716]
> * sysdeps/ieee754/soft-fp/s_fdiv.c: Fix build with -O.
> diff --git a/locale/weight.h b/locale/weight.h
> index 6028d3595e..10bcea25e5 100644
> --- a/locale/weight.h
> +++ b/locale/weight.h
> @@ -28,7 +28,14 @@ findidx (const int32_t *table,
> const unsigned char *extra,
> const unsigned char **cpp, size_t len)
> {
> + /* With GCC 8 when compiling with -Os the compiler warns that
> + seq1.back_us and seq2.back_us might be used uninitialized.
> + This uninitialized use is impossible for the same reason
> + as described in comments in locale/weightwc.h. */
> + DIAG_PUSH_NEEDS_COMMENT;
> + DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
> int_fast32_t i = table[*(*cpp)++];
> + DIAG_POP_NEEDS_COMMENT;
> const unsigned char *cp;
> const unsigned char *usrc;
>
> --
> 2.17.1
>
@@ -1,3 +1,7 @@
+2018-09-30 Martin Jansa <Martin.Jansa@gmail.com>
+ Partial fix for [BZ #23716]
+ * locale/weight.h: Fix build with -Os.
+
2018-09-30 Martin Jansa <Martin.Jansa@gmail.com>
Partial fix for [BZ #23716]
* sysdeps/ieee754/soft-fp/s_fdiv.c: Fix build with -O.
@@ -28,7 +28,14 @@ findidx (const int32_t *table,
const unsigned char *extra,
const unsigned char **cpp, size_t len)
{
+ /* With GCC 8 when compiling with -Os the compiler warns that
+ seq1.back_us and seq2.back_us might be used uninitialized.
+ This uninitialized use is impossible for the same reason
+ as described in comments in locale/weightwc.h. */
+ DIAG_PUSH_NEEDS_COMMENT;
+ DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
int_fast32_t i = table[*(*cpp)++];
+ DIAG_POP_NEEDS_COMMENT;
const unsigned char *cp;
const unsigned char *usrc;