Re: [PATCH] LoongArch: ldconfig: Ignore EF_LARCH_OBJABI_V1 in shared objects

[Carlos O'Donell <carlos@redhat.com>]

On 3/26/23 07:13, Xi Ruoyao via Libc-alpha wrote:
> Binutils 2.40 sets EF_LARCH_OBJABI_V1 for shared objects:
> 
>     $ ld --version | head -n1
>     GNU ld (GNU Binutils) 2.40
>     $ echo 'int dummy;' > dummy.c
>     $ cc dummy.c -shared
>     $ readelf -h a.out | grep Flags
>     Flags:                             0x43, DOUBLE-FLOAT, OBJ-v1
> 
> We need to ignore it in ldconfig or ldconfig will consider all shared
> objects linked by Binutils 2.40 "unsupported".  Maybe we should stop
> setting EF_LARCH_OBJABI_V1 for shared objects, but Binutils 2.40 is
> already released and we cannot change it.
> ---
>  sysdeps/unix/sysv/linux/loongarch/readelflib.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/loongarch/readelflib.c b/sysdeps/unix/sysv/linux/loongarch/readelflib.c
> index bcaff86b36..ceba355959 100644
> --- a/sysdeps/unix/sysv/linux/loongarch/readelflib.c
> +++ b/sysdeps/unix/sysv/linux/loongarch/readelflib.c
> @@ -40,7 +40,7 @@ process_elf_file (const char *file_name, const char *lib, int *flag,
>  
>    ret = process_elf64_file (file_name, lib, flag, isa_level, soname,
>  				file_contents, file_length);
> -  flags = elf64_header->e_flags;
> +  flags = elf64_header->e_flags & ~EF_LARCH_OBJABI_V1;

Are such objects ABI compatible?

Why isn't this handled below via SUPPORTED_ELF_FLAGS?

>  
>    /* LoongArch linkers encode the floating point ABI as part of the ELF headers.  */
>    switch (flags & SUPPORTED_ELF_FLAGS)

-- 
Cheers,
Carlos.