[RS6000] Don't support inline PLT for ABI_V4 bss-plt

[Segher Boessenkool]

Hi Alan,

On Fri, Feb 08, 2019 at 11:05:57AM +1030, Alan Modra wrote:
> Inline PLT calls need PLT to be an array of addresses.  bss-plt works
> differently.
> 
> Bootstrap and regression test on powerpc64-linux biarch in progress.
> OK assuming no regressions?
> 
> 	* config/rs6000/rs6000.c (rs6000_longcall_ref): Don't use
> 	inline plt for ABI_V4 bss-plt.
> 	(rs6000_call_sysv): Likewise.
> 
> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> index 711278c7422..cced90bb518 100644
> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c
> @@ -32819,7 +32819,8 @@ rs6000_longcall_ref (rtx call_ref, rtx arg)
>      }
>  
>    if (HAVE_AS_PLTSEQ
> -      && (DEFAULT_ABI == ABI_ELFv2 || DEFAULT_ABI == ABI_V4))
> +      && (DEFAULT_ABI == ABI_ELFv2
> +	  || (DEFAULT_ABI == ABI_V4 && TARGET_SECURE_PLT)))
>      {
>        rtx base = const0_rtx;
>        int regno;
> @@ -37981,7 +37982,7 @@ rs6000_call_sysv (rtx value, rtx func_desc, rtx tlsarg, rtx cookie)
>        func = rs6000_longcall_ref (func_desc, tlsarg);
>        /* If the longcall was implemented using PLT16 relocs, then r11
>  	 needs to be valid at the call for lazy linking.  */

This comment could use some work.

> -      if (HAVE_AS_PLTSEQ)
> +      if (HAVE_AS_PLTSEQ && REGNO (func) == 11)

This (and all occurrences below) need some explanation.  It is probably
best if you factor out

  bool something = (REGNO (func) == 11));

(with a descriptive name) and use that?

The patch is okay (for all branches) with those things improved.  Thanks!


Segher