Re: regression with binutils 2.28 for ppc

[Waldemar Brodkorb <wbx@openadk.org>]

Hi Alan,
Alan Modra wrote,

> All things considered, I think all I can do in gas is to partially
> revert commit b25f942e18d6 which made .machine more strict.  At least
> that way -many (passed by release gcc) or other user sticky -Wa
> options like -maltivec will not be lost.  Bad luck if a user wants
> -mcpu=power9 -Wa,-power10 for example.
> 
> 	* config/tc-ppc.c (ppc_machine): Treat an early .machine specially,
> 	keeping sticky options to work around gcc bugs.
> 
> diff --git a/gas/config/tc-ppc.c b/gas/config/tc-ppc.c
> index 054f9c72161..89bc7d3f9b9 100644
> --- a/gas/config/tc-ppc.c
> +++ b/gas/config/tc-ppc.c
> @@ -5965,7 +5965,30 @@ ppc_machine (int ignore ATTRIBUTE_UNUSED)
>  	     options do not count as a new machine, instead they add
>  	     to currently selected opcodes.  */
>  	  ppc_cpu_t machine_sticky = 0;
> -	  new_cpu = ppc_parse_cpu (ppc_cpu, &machine_sticky, cpu_string);
> +	  /* Unfortunately, some versions of gcc emit a .machine
> +	     directive very near the start of the compiler's assembly
> +	     output file.  This is bad because it overrides user -Wa
> +	     cpu selection.  Worse, there are versions of gcc that
> +	     emit the *wrong* cpu, not even respecting the -mcpu given
> +	     to gcc.  See gcc pr101393.  And to compound the problem,
> +	     as of 20220222 gcc doesn't pass the correct cpu option to
> +	     gas on the command line.  See gcc pr59828.  Hack around
> +	     this by keeping sticky options for an early .machine.  */
> +	  asection *sec;
> +	  for (sec = stdoutput->sections; sec != NULL; sec = sec->next)
> +	    {
> +	      segment_info_type *info = seg_info (sec);
> +	      /* Are the frags for this section perturbed from their
> +		 initial state?  Even .align will count here.  */
> +	      if (info != NULL
> +		  && (info->frchainP->frch_root != info->frchainP->frch_last
> +		      || info->frchainP->frch_root->fr_type != rs_fill
> +		      || info->frchainP->frch_root->fr_fix != 0))
> +		break;
> +	    }
> +	  new_cpu = ppc_parse_cpu (ppc_cpu,
> +				   sec == NULL ? &sticky : &machine_sticky,
> +				   cpu_string);
>  	  if (new_cpu != 0)
>  	    ppc_cpu = new_cpu;
>  	  else

That fixes the kernel compile for me, too. thanks Alan!

best regards
 Waldemar