PATCH: Fix 2 PPC/SYSV varargs problems
Richard Henderson
rth at cygnus.com
Fri Apr 30 12:48:17 EST 1999
On Fri, Apr 30, 1999 at 02:09:09AM +0200, Franz Sirl wrote:
> 1. the varargs save area calculation bug, this is a hack and Richard ;-)
> probably won't like it, but maybe it's good enough for egcs-1.2
You're right -- I hate it. You'll have made it so I can't build a
ppc cross compiler on my Alphas, and you'll have killed the compiler
for a ppc64-linux.
Here's an implementation of what I'd suggested before. It looks ok
to the eye, but I don't have a ppc-linux box handy to try it out on.
r~
* va-ppc.h (__va_start_common): Let __builtin_saveregs do the work.
* rs6000.c (expand_builtin_saveregs): For SYSV, initialize a private
va_list struct, and return a pointer to it.
Index: ginclude/va-ppc.h
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/ginclude/va-ppc.h,v
retrieving revision 1.4
diff -c -p -d -r1.4 va-ppc.h
*** va-ppc.h 1998/12/16 21:19:40 1.4
--- va-ppc.h 1999/04/30 02:45:30
*************** typedef struct {
*** 59,92 ****
((TYPE *) (void *) (&(((__va_regsave_t *) \
(AP)->reg_save_area)->__gp_save[(int)(AP)->gpr])))
! /* Common code for va_start for both varargs and stdarg. This depends
! on the format of rs6000_args in rs6000.h. The fields used are:
!
! #0 WORDS # words used for GP regs/stack values
! #1 FREGNO next available FP register
! #2 NARGS_PROTOTYPE # args left in the current prototype
! #3 ORIG_NARGS original value of NARGS_PROTOTYPE
! #4 VARARGS_OFFSET offset from frame pointer of varargs area */
!
! #define __va_words __builtin_args_info (0)
! #define __va_fregno __builtin_args_info (1)
! #define __va_nargs __builtin_args_info (2)
! #define __va_orig_nargs __builtin_args_info (3)
! #define __va_varargs_offset __builtin_args_info (4)
! #define __va_start_common(AP, FAKE) \
! __extension__ ({ \
! register int __words = __va_words - FAKE; \
! \
! (AP)->gpr = (__words < 8) ? __words : 8; \
! (AP)->fpr = __va_fregno - 33; \
! (AP)->reg_save_area = (((char *) __builtin_frame_address (0)) \
! + __va_varargs_offset); \
! __va_overflow(AP) = ((char *)__builtin_saveregs () \
! + (((__words >= 8) ? __words - 8 : 0) \
! * sizeof (long))); \
! (void)0; \
! })
#ifdef _STDARG_H /* stdarg.h support */
--- 59,71 ----
((TYPE *) (void *) (&(((__va_regsave_t *) \
(AP)->reg_save_area)->__gp_save[(int)(AP)->gpr])))
! /* Common code for va_start for both varargs and stdarg. We allow all
! the work to be done by __builtin_saveregs. It returns a pointer to
! a va_list that was constructed on the stack; we must simply copy it
! to the user's variable. */
! #define __va_start_common(AP, FAKE) \
! __builtin_memcpy ((AP), __builtin_saveregs (), sizeof(__gnuc_va_list))
#ifdef _STDARG_H /* stdarg.h support */
Index: config/rs6000/rs6000.c
===================================================================
RCS file: /egcs/carton/cvsfiles/egcs/gcc/config/rs6000/rs6000.c,v
retrieving revision 1.66
diff -c -p -d -r1.66 rs6000.c
*** rs6000.c 1999/04/27 12:39:58 1.66
--- rs6000.c 1999/04/30 02:45:30
*************** setup_incoming_varargs (cum, mode, type,
*** 1704,1716 ****
On the Power/PowerPC return the address of the area on the stack
used to hold arguments. Under AIX, this includes the 8 word register
! save area. Under V.4 this does not. */
struct rtx_def *
expand_builtin_saveregs (args)
tree args ATTRIBUTE_UNUSED;
{
! return virtual_incoming_args_rtx;
}
--- 1704,1786 ----
On the Power/PowerPC return the address of the area on the stack
used to hold arguments. Under AIX, this includes the 8 word register
! save area.
!
! Under V.4, things are more complicated. We do not have access to
! all of the virtual registers required for va_start to do its job,
! so we construct the va_list in its entirity here, and reduce va_start
! to a block copy. This is similar to the way we do things on Alpha. */
struct rtx_def *
expand_builtin_saveregs (args)
tree args ATTRIBUTE_UNUSED;
{
! rtx block, mem_gpr_fpr, mem_reg_save_area, mem_overflow, tmp;
! tree fntype;
! int stdarg_p;
! HOST_WIDE_INT words, gpr, fpr;
!
! if (DEFAULT_ABI != ABI_V4 && DEFAULT_ABI != ABI_SOLARIS)
! return virtual_incoming_args_rtx;
!
! fntype = TREE_TYPE (current_function_decl);
! stdarg_p = (TYPE_ARG_TYPES (fntype) != 0
! && (TREE_VALUE (tree_last (TYPE_ARG_TYPES (fntype)))
! != void_type_node));
!
! /* Allocate the va_list constructor. */
! block = assign_stack_local (BLKmode, 3 * UNITS_PER_WORD, BITS_PER_WORD);
! RTX_UNCHANGING_P (block) = 1;
! RTX_UNCHANGING_P (XEXP (block, 0)) = 1;
!
! mem_gpr_fpr = change_address (block, word_mode, XEXP (block, 0));
! mem_overflow = change_address (block, ptr_mode,
! plus_constant (XEXP (block, 0),
! UNITS_PER_WORD));
! mem_reg_save_area = change_address (block, ptr_mode,
! plus_constant (XEXP (block, 0),
! 2 * UNITS_PER_WORD));
!
! /* Construct the two characters of `gpr' and `fpr' as a unit. */
! words = current_function_args_info.words - !stdarg_p;
! gpr = (words > 8 ? 8 : words);
! fpr = current_function_args_info.fregno - 33;
!
! if (BYTES_BIG_ENDIAN)
! {
! HOST_WIDE_INT bits = gpr << 8 | fpr;
! if (HOST_BITS_PER_WIDE_INT >= BITS_PER_WORD)
! tmp = GEN_INT (bits << (BITS_PER_WORD - 16));
! else
! {
! bits <<= BITS_PER_WORD - HOST_BITS_PER_WIDE_INT - 16;
! tmp = immed_double_const (0, bits, word_mode);
! }
! }
! else
! tmp = GEN_INT (fpr << 8 | gpr);
!
! emit_move_insn (mem_gpr_fpr, tmp);
!
! /* Find the overflow area. */
! if (words <= 8)
! tmp = virtual_incoming_args_rtx;
! else
! tmp = expand_binop (Pmode, add_optab, virtual_incoming_args_rtx,
! GEN_INT ((words - 8) * UNITS_PER_WORD),
! mem_overflow, 0, OPTAB_WIDEN);
! if (tmp != mem_overflow)
! emit_move_insn (mem_overflow, tmp);
!
! /* Find the register save area. */
! tmp = expand_binop (Pmode, add_optab, virtual_stack_vars_rtx,
! GEN_INT (-RS6000_VARARGS_SIZE),
! mem_reg_save_area, 0, OPTAB_WIDEN);
! if (tmp != mem_reg_save_area)
! emit_move_insn (mem_reg_save_area, tmp);
!
! /* Return the address of the va_list constructor. */
! return XEXP (block, 0);
}
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