This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: Fix two more -Os strcoll / wcscoll build failures
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Tue, 27 Feb 2018 10:34:36 -0300
- Subject: Re: Fix two more -Os strcoll / wcscoll build failures
- Authentication-results: sourceware.org; auth=none
- References: <alpine.DEB.2.20.1802262152320.2986@digraph.polyomino.org.uk>
On 26/02/2018 18:53, Joseph Myers wrote:
> Continuing fixes for -Os build issues shown with build-many-glibcs.py,
> this patch adds uses of DIAG_* to disable -Wmaybe-uninitialized in two
> more places where code inlined from strcoll / wcscoll is wrongly
> diagnosed as possibly using uninitialized structure fields. (All
> these warnings in different places for these functions are I think
> essentially the same bug.)
>
> Tested with build-many-glibcs.py for alpha-linux-gnu and
> mips-linux-gnu that this fixes the -Os build failures for those
> configurations with GCC 7.
>
> 2018-02-26 Joseph Myers <joseph@codesourcery.com>
>
> * locale/weightwc.h (findidx): Ignore -Wmaybe-uninitialized for
> -Os in two more places.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
>
> diff --git a/locale/weightwc.h b/locale/weightwc.h
> index ac25ba9..36c65b5 100644
> --- a/locale/weightwc.h
> +++ b/locale/weightwc.h
> @@ -28,7 +28,15 @@ findidx (const int32_t *table,
> const wint_t *extra,
> const wint_t **cpp, size_t len)
> {
> + /* With GCC 7 when compiling with -Os the compiler warns that
> + seq1.back_us and seq2.back_us, which become *cpp, might be used
> + uninitialized. This is impossible as this function cannot be
> + called except in cases where those fields have been
> + initialized. */
> + DIAG_PUSH_NEEDS_COMMENT;
> + DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
> wint_t ch = *(*cpp)++;
> + DIAG_POP_NEEDS_COMMENT;
> int32_t i = __collidx_table_lookup ((const char *) table, ch);
>
> if (i >= 0)
> @@ -107,11 +115,18 @@ findidx (const int32_t *table,
> continue;
> }
>
> + /* With GCC 7 when compiling with -Os the compiler warns
> + that seq1.back_us and seq2.back_us, which become usrc,
> + might be used uninitialized. This is impossible for the
> + same reason as described above. */
> + DIAG_PUSH_NEEDS_COMMENT;
> + DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized");
> if (cp[nhere - 1] > usrc[nhere -1])
> {
> cp += 2 * nhere;
> continue;
> }
> + DIAG_POP_NEEDS_COMMENT;
>
> if (cp[2 * nhere - 1] < usrc[nhere -1])
> {
>