Re: [RFA] sh-tdep.c (sh_use_struct_convention): Restructure and fix

[Elena Zannoni <ezannoni at redhat dot com>]

Corinna Vinschen writes:
 > On Fri, Oct 10, 2003 at 12:43:27PM -0400, Elena Zannoni wrote:
 > > Corinna Vinschen writes:
 > >  > static int
 > >  > sh_use_struct_convention (int gcc_p, struct type *type)
 > >  > {
 > >  >   int len = TYPE_LENGTH (type);
 > >  >   int nelem = TYPE_NFIELDS (type);
 > >  > 
 > >  >   /* Non-power of 2 length types and types bigger than 8 bytes (which don't
 > >  >      fit in two registers anyway) use struct convention.  */
 > >  >   if (len != 1 && len != 2 && len != 4 && len != 8)
 > >  >     return 1;
 > >  > 
 > >  >   /* Scalar types and aggregate types with exactly one field are aligned
 > >  >      by definition.  They are returned in registers.  */
 > >  >   if (nelem <= 1)
 > >  >     return 0;
 > >  > 
 > >  >   /* If the first field in the aggregate has the same length as the entire
 > >  >      aggregate type, the type is returned in registers.  */
 > >  >   if (TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) == len)
 > >  >     return 0;
 > >  > 
 > >  >   /* If the size of the aggregate is 8 bytes and the first field is
 > >  >      of size 4 bytes its alignment is equal to long long's alignment,
 > >  >      so it's returned in registers.  */
 > >  >   if (len == 8 && TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) == 4)
 > >  >     return 0;
 > >  > 
 > >  >   /* Otherwise use struct convention.  */
 > >  >   return 1;
 > >  > }
 > > 
 > > Much better, however, I would still like to know what the behavior is
 > > for a struct of 2 chars.  Probably this needs another test case.
 > 
 > A struct of two chars is returned in memory.  That's correct.

OK, after careful re-re-re-parsing of the description, I think so too.

I'll add another comment to explain that case better.

This can go in.

elena


 > 
 > Corinna
 > 
 > -- 
 > Corinna Vinschen
 > Cygwin Developer
 > Red Hat, Inc.