Re: [PATCH 3/8] sparc: Rewrite everything

[Richard Henderson <rth@twiddle.net>]

On 10/29/2014 11:10 AM, David Miller wrote:
> From: Richard Henderson <rth@twiddle.net>
> Date: Tue, 28 Oct 2014 12:45:50 -0700
> 
>> +    case FFI_TYPE_STRUCT:
>> +      if (rtype->size > 32)
>> +	{
>> +	  flags = SPARC_RET_VOID | SPARC_FLAG_RET_IN_MEM;
>> +	  bytes = 8;
>> +	}
>> +      else
>> +	flags = SPARC_RET_STRUCT;
>> +      break;
> 
> Here you use a cutoff of 32 bytes.

Return type.

> 
>> +	case FFI_TYPE_LONGDOUBLE:
>> +	case FFI_TYPE_STRUCT:
>> +	  z = ty->size;
>> +	  if (z > 16)
>> +	    {
>> +	      /* For structures larger than 16 bytes we pass reference.  */
>> +	      *argp++ = (unsigned long)a;
>> +	      break;
>> +	    }
>> +	  if (((unsigned long)argp & 15) && ty->alignment > 8)
>> +	    argp++;
>> +	  memcpy(argp, a, z);
>> +	  argp += ALIGN(z, 8) / 8;
>> +	  break;
> 
> Yet here in args prep, the cutoff is 16.

Parameter type.

> Maybe I'm missing something?

The two limits are in fact different.  In gcc, see sparc_return_in_memory and
sparc_pass_by_reference.


r~