Re: [RFA] Mips, return_value_location, small structs

[Michael Snyder <msnyder@redhat.com>]

Andrew Cagney wrote:
> 
> > Re-submitted as a separate patch.
> >
> > The problem: small structs returned in one (or two) registers
> > are aligned left in N32/N64 and aligned right in the others
> > (or vice versa, depending on how you cross your eyes).
> 
> I _think_ you also need to add o32.  Can you check that out?  Just post
> the results, not the patch.

I know o32 needs work too, but the two can be treated separately.
I do guarantee that this patch does not make o32 any worse.
In fact, I have been testing to make sure that none of my patches
have made o32 any worse.

Can I check this one in for n32, if I promise to work on o32 next?


> 
> Andrew
> 
> > There are two code paths here, one for structs of length < MIPS_REGSIZE,
> > and one for MIPS_REGSIZE < struct len < 2 * MIPS_REGSIZE.
> >
> > The first case I've split into two paths: one for N32 &&
> > TYPE_CODE_STRUCT,
> > and a second for everything else (the later being identical to what was
> > there before).
> >
> > In the second case, I've simply let the N32/N64 path fall thru.
> > The next "if" catches it and handles it correctly.
> >
> >
> >
> > 2002-08-08  Michael Snyder  <msnyder@redhat.com>
> >
> >       * mips-tdep.c (return_value_location): Structs returned in
> >       registers are aligned differently (n32/64 vs. o32/64).
> >
> > Index: mips-tdep.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/mips-tdep.c,v
> > retrieving revision 1.92
> > diff -c -3 -p -r1.92 mips-tdep.c
> > *** mips-tdep.c       8 Aug 2002 00:26:51 -0000       1.92
> > --- mips-tdep.c       8 Aug 2002 21:48:09 -0000
> > *************** return_value_location (struct type *valt
> > *** 3608,3622 ****
> >         if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
> >         && len < MIPS_SAVED_REGSIZE)
> >       {
> > !       /* "un-left-justify" the value in the low register */
> > !       lo->reg_offset = MIPS_SAVED_REGSIZE - len;
> > !       lo->len = len;
> >         hi->reg_offset = 0;
> >         hi->len = 0;
> >       }
> >         else if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
> >              && len > MIPS_SAVED_REGSIZE      /* odd-size structs */
> >              && len < MIPS_SAVED_REGSIZE * 2
> >              && (TYPE_CODE (valtype) == TYPE_CODE_STRUCT ||
> >                  TYPE_CODE (valtype) == TYPE_CODE_UNION))
> >       {
> > --- 3608,3635 ----
> >         if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
> >         && len < MIPS_SAVED_REGSIZE)
> >       {
> > !       if ((gdbarch_tdep (current_gdbarch) -> mips_abi == MIPS_ABI_N32
> > !            || gdbarch_tdep (current_gdbarch) -> mips_abi == MIPS_ABI_N64)
> > !           && (TYPE_CODE (valtype) == TYPE_CODE_STRUCT
> > !               || TYPE_CODE (valtype) == TYPE_CODE_UNION))
> > !         {
> > !           /* Values are already aligned in the low register.  */
> > !           lo->reg_offset = 0;
> > !         }
> > !       else
> > !         {
> > !           /* "un-left-justify" the value in the low register */
> > !           lo->reg_offset = MIPS_SAVED_REGSIZE - len;
> > !         }
> >         hi->reg_offset = 0;
> > +       lo->len = len;
> >         hi->len = 0;
> >       }
> >         else if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
> >              && len > MIPS_SAVED_REGSIZE      /* odd-size structs */
> >              && len < MIPS_SAVED_REGSIZE * 2
> > +            && gdbarch_tdep (current_gdbarch) -> mips_abi != MIPS_ABI_N32
> > +            && gdbarch_tdep (current_gdbarch) -> mips_abi != MIPS_ABI_N64
> >              && (TYPE_CODE (valtype) == TYPE_CODE_STRUCT ||
> >                  TYPE_CODE (valtype) == TYPE_CODE_UNION))
> >       {