[PATCH] rs6000: Compute rop_hash_save_offset for non-Altivec compiles [PR115389]

[Peter Bergner]

On 6/13/24 12:35 AM, Kewen.Lin wrote:
>> @@ -826,7 +826,14 @@ rs6000_stack_info (void)
>>  	  info->ehrd_offset -= info->rop_hash_size;
>>  	}
>>        else
>> -	info->ehrd_offset = info->gp_save_offset - ehrd_size;
>> +	{
>> +	  info->ehrd_offset = info->gp_save_offset - ehrd_size;
>> +
>> +	  /* Adjust for ROP protection.  */
>> +	  info->rop_hash_save_offset
>> +	    = info->gp_save_offset - info->rop_hash_size;
>> +	  info->ehrd_offset -= info->rop_hash_size;
>> +	}
> 
> I understand this is just copied from the if arm, but if I read this right, it can be
> simplified as:

Ok, I'll retest with that simplification.





>> +/* { dg-do assemble } */
>> +/* { dg-options "-O2 -mdejagnu-cpu=power10 -mrop-protect -mno-vsx -mno-altivec -mabi=no-altivec -save-temps" } */
> 
> I'd expect -mabi=no-altivec is default for -mno-altivec, but specifying it explicitly
> looks fine to me. :)

That's what I expected too! :-)  However, I was surprised to learn that -mno-altivec
does *not* disable TARGET_ALTIVEC_ABI.  I had to explicitly use the -mabi= option to
expose the bug.



Peter