[PATCH] gas: Silence GCC 10 warning tc-vax.c

[Martin Sebor]

On 5/26/20 8:41 AM, H.J. Lu via Binutils wrote:
> 	PR gas/26044
> 	* config/tc-vax.c (md_estimate_size_before_relax): Replace
> 	fragP->fr_literal with &fragP->fr_literal[0].
> 	(md_convert_frag): Likewise.
> ---
>   gas/ChangeLog       | 7 +++++++
>   gas/config/tc-vax.c | 4 ++--
>   2 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/gas/ChangeLog b/gas/ChangeLog
> index 052d180398..980a84f6cf 100644
> --- a/gas/ChangeLog
> +++ b/gas/ChangeLog
> @@ -1,3 +1,10 @@
> +2020-05-26  H.J. Lu  <hongjiu.lu@intel.com>
> +
> +	PR gas/26044
> +	* config/tc-vax.c (md_estimate_size_before_relax): Replace
> +	fragP->fr_literal with &fragP->fr_literal[0].
> +	(md_convert_frag): Likewise.
> +
>   2020-05-26  H.J. Lu  <hongjiu.lu@intel.com>
>   
>   	PR gas/26044
> diff --git a/gas/config/tc-vax.c b/gas/config/tc-vax.c
> index 5634566945..f606c157bc 100644
> --- a/gas/config/tc-vax.c
> +++ b/gas/config/tc-vax.c
> @@ -381,7 +381,7 @@ md_estimate_size_before_relax (fragS *fragP, segT segment)
>   	  int old_fr_fix;
>   
>   	  old_fr_fix = fragP->fr_fix;
> -	  p = fragP->fr_literal + old_fr_fix;
> +	  p = &fragP->fr_literal[0] + old_fr_fix;

For what it's worth, I'd expect the following to suppress the warning
as well without overly obfuscating the code:

   p = &fragP->fr_literal[old_fr_fix];

Either way, although I intend to suppress the warning in GCC for this
case, the GCC manual discourages using trailing arrays of non-zero
size as flexible array members, in favor of either the C99 feature
itself or the zero-length array extension (see Zero-Length.html).
If it's not overly disruptive I would suggest to consider adjusting
those accordingly.

Martin

>   #ifdef OBJ_ELF
>   	  /* If this is to an undefined symbol, then if it's an indirect
>   	     reference indicate that is can mutated into a GLOB_DAT or
> @@ -525,7 +525,7 @@ md_convert_frag (bfd *headers ATTRIBUTE_UNUSED,
>   
>     know (fragP->fr_type == rs_machine_dependent);
>     where = fragP->fr_fix;
> -  addressP = fragP->fr_literal + where;
> +  addressP = &fragP->fr_literal[0] + where;
>     opcodeP = fragP->fr_opcode;
>     symbolP = fragP->fr_symbol;
>     know (symbolP);
>