Re: -Wstringop-truncation warnings

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, May 4, 2018 at 2:32 AM, Alan Modra <amodra@gmail.com> wrote:
> This patch is aimed at silencing gcc8 -Wstringop-truncation warnings.
>
> Unfortunately adding  __attribute__ ((__nonstring)) doesn't work in a
> number of the places patched here, (see
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85643) so if you have
> recent glibc headers installed you'll need to configure binutils with
> --disable-werror to compile using gcc8 or gcc9.
>
> include/
>         * ansidecl.h: Import from gcc.
>         * coff/internal.h (struct internal_scnhdr): Add ATTRIBUTE_NONSTRING
>         to s_name.
>         (struct internal_syment): Add ATTRIBUTE_NONSTRING to _n_name.
> bfd/
>         * elf-linux-core.h (struct elf_external_linux_prpsinfo32_ugid32),
>         (struct elf_external_linux_prpsinfo32_ugid16),
>         (struct elf_external_linux_prpsinfo64_ugid32),
>         (struct elf_external_linux_prpsinfo64_ugid16): Add ATTRIBUTE_NONSTRING
>         to pr_fname and pr_psargs fields.  Remove GCC diagnostic pragmas.
>         Move comment to..
>         * elf.c (elfcore_write_prpsinfo): ..here.  Indent nested preprocessor
>         directives.
>         * elf32-arm.c (elf32_arm_nabi_write_core_note): Add ATTRIBUTE_NONSTRING
>         to data.
>         * elf32-ppc.c (ppc_elf_write_core_note): Likewise.
>         * elf32-s390.c (elf_s390_write_core_note): Likewise.
>         * elf64-s390.c (elf_s390_write_core_note): Likewise.
>         * elfxx-aarch64.c (_bfd_aarch64_elf_write_core_note): Likewise.
>         * elf64-x86-64.c (elf_x86_64_write_core_note): Add GCC diagnostic
>         pragmas.
>         * peXXigen.c (_bfd_XXi_swap_scnhdr_out): Use strnlen to avoid
>         false positive gcc-8 warning.
> gas/
>         * config/obj-evax.c (shorten_identifier): Use memcpy in place
>         of strncpy.
>         * config/obj-macho.c (obj_mach_o_make_or_get_sect): Ensure
>         segname and sectname fields are NUL terminated.
>
> diff --git a/bfd/cofflink.c b/bfd/cofflink.c
> index fb1696afff..6ca547ce5b 100644
> --- a/bfd/cofflink.c
> +++ b/bfd/cofflink.c
> @@ -1839,7 +1839,7 @@ _bfd_coff_link_input_bfd (struct coff_final_link_info *flaginfo, bfd *input_bfd)
>
>             case C_FCN:
>               if (obj_pe (input_bfd)
> -                 && strcmp (isym.n_name, ".bf") != 0
> +                 && strncmp (isym.n_name, ".bf", sizeof isym.n_name) != 0
>                   && isym.n_scnum > 0)
>                 {
>                   /* For PE, .lf and .ef get their value left alone,

If this is truly non-string, can memcmp be used instead?


-- 
H.J.