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Re: [rfa] mips argument passing fixes for o32
- To: Daniel Jacobowitz <dmj+ at andrew dot cmu dot edu>
- Subject: Re: [rfa] mips argument passing fixes for o32
- From: Andrew Cagney <ac131313 at cygnus dot com>
- Date: Thu, 12 Jul 2001 03:44:18 -0400
- Cc: gdb-patches at sources dot redhat dot com
- References: <20010706112635.A5870@nevyn.them.org>
> These are based on testsuite failures (call-*-st, if I remember correctly)
> and reading the argument passing code in GCC. The struct alignment fix
> definitely agrees with the ABI, though it's not always clear on this point -
> it becomes necessary for us when the return value is a struct and thus there
> is a hidden pointer as the first argument. The shift fix matches this
> comment in GCC and is not really specified by the ABI document:
I get the feeling that these two changes fix two separate bugs:
o botched struct parameter pass
o botched struct return
Looking at just the first one:
> + /* Structures should be aligned to eight bytes (even arg registers)
> + on MIPS_ABI_O32 if their first member has double precision. */
> + if (gdbarch_tdep (current_gdbarch)->mips_abi == MIPS_ABI_O32
> + && mips_type_needs_double_align (arg_type))
> + {
> + argreg += argreg & 1;
> + }
this is approved. However could you please change the expression:
argreg += argreg & 1;
to something like:
if ((argreg & 1))
argreg++;
your original expression makes my head hurt :-)
Andrew