[RFA] mips-n32 reg_struct_has_addr

[RFA] mips-n32 reg_struct_has_addr

[Michael Snyder]

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This patch gdbarch-ifies reg_struct_has_addr for mips, 
and then makes it work correctly for N32.  In the process, 
we move the functionality of reg_struct_has_addr out of
mips_push_arguments and put it where it belongs.

This is the other half of my earlier N32 patch.

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2002-08-01  Michael Snyder  <msnyder@redhat.com>

	*  mips-tdep.c 	(mips_eabi_reg_struct_has_addr, 
	mips_newabi_reg_struct_has_addr, 
	mips_oldabi_reg_struct_has_addr): New gdbarch functions.
	(mips_push_argument): Don't convert struct args to pointers,
	leave it to REG_STRUCT_HAS_ADDR.
	(mips_gdbarch_init): Set gdbarch_reg_struct_has_addr.

Index: mips-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/mips-tdep.c,v
retrieving revision 1.87
diff -c -3 -p -r1.87 mips-tdep.c
*** mips-tdep.c	1 Aug 2002 21:36:27 -0000	1.87
--- mips-tdep.c	2 Aug 2002 02:01:01 -0000
*************** mips_use_struct_convention (int gcc_p, s
*** 567,572 ****
--- 567,606 ----
      return 1;			/* Structures are returned by ref in extra arg0 */
  }
  
+ /* Should call_function pass struct by reference? 
+    For each architecture, structs are passed either by
+    value or by reference, depending on their size.  */
+ 
+ static int
+ mips_eabi_reg_struct_has_addr (int gcc_p, struct type *type)
+ {
+   enum type_code typecode = TYPE_CODE (check_typedef (type));
+   int len = TYPE_LENGTH (check_typedef (type));
+ 
+   if (typecode == TYPE_CODE_STRUCT || typecode == TYPE_CODE_UNION)
+     return (len > MIPS_SAVED_REGSIZE);
+ 
+   return 0;
+ }
+ 
+ static int
+ mips_newabi_reg_struct_has_addr (int gcc_p, struct type *type)
+ {
+   enum type_code typecode = TYPE_CODE (check_typedef (type));
+   int len = TYPE_LENGTH (check_typedef (type));
+ 
+   if (typecode == TYPE_CODE_STRUCT   || typecode == TYPE_CODE_UNION)
+     return (len > MIPS_SAVED_REGSIZE && len % MIPS_SAVED_REGSIZE != 0);
+ 
+   return 0;
+ }
+ 
+ int
+ mips_oldabi_reg_struct_has_addr (int gcc_p, struct type *type)
+ {
+   return 0;	/* FIXME: what should we do for old abi?  */
+ }
+ 
  /* Tell if the program counter value in MEMADDR is in a MIPS16 function.  */
  
  static int
*************** mips_push_arguments (int nargs,
*** 2428,2448 ****
  			    "mips_push_arguments: %d len=%d type=%d",
  			    argnum + 1, len, (int) typecode);
  
!       /* The EABI passes structures that do not fit in a register by
!          reference. In all other cases, pass the structure by value.  */
!       if (MIPS_EABI
! 	  && len > MIPS_SAVED_REGSIZE
! 	  && (typecode == TYPE_CODE_STRUCT || typecode == TYPE_CODE_UNION))
! 	{
! 	  store_address (valbuf, MIPS_SAVED_REGSIZE, VALUE_ADDRESS (arg));
! 	  typecode = TYPE_CODE_PTR;
! 	  len = MIPS_SAVED_REGSIZE;
! 	  val = valbuf;
! 	  if (mips_debug)
! 	    fprintf_unfiltered (gdb_stdlog, " push");
! 	}
!       else
! 	val = (char *) VALUE_CONTENTS (arg);
  
        /* 32-bit ABIs always start floating point arguments in an
           even-numbered floating point register.  Round the FP register
--- 2462,2468 ----
  			    "mips_push_arguments: %d len=%d type=%d",
  			    argnum + 1, len, (int) typecode);
  
!       val = (char *) VALUE_CONTENTS (arg);
  
        /* 32-bit ABIs always start floating point arguments in an
           even-numbered floating point register.  Round the FP register
*************** mips_gdbarch_init (struct gdbarch_info i
*** 4472,4477 ****
--- 4492,4500 ----
        set_gdbarch_long_bit (gdbarch, 32);
        set_gdbarch_ptr_bit (gdbarch, 32);
        set_gdbarch_long_long_bit (gdbarch, 64);
+       /* Set up reg_struct_has_addr.  */
+       set_gdbarch_reg_struct_has_addr (gdbarch, 
+ 				       mips_oldabi_reg_struct_has_addr);
        break;
      case MIPS_ABI_O64:
        tdep->mips_default_saved_regsize = 8;
*************** mips_gdbarch_init (struct gdbarch_info i
*** 4485,4490 ****
--- 4508,4516 ----
        set_gdbarch_long_bit (gdbarch, 32);
        set_gdbarch_ptr_bit (gdbarch, 32);
        set_gdbarch_long_long_bit (gdbarch, 64);
+       /* Set up reg_struct_has_addr.  */
+       set_gdbarch_reg_struct_has_addr (gdbarch, 
+ 				       mips_oldabi_reg_struct_has_addr);
        break;
      case MIPS_ABI_EABI32:
        tdep->mips_default_saved_regsize = 4;
*************** mips_gdbarch_init (struct gdbarch_info i
*** 4498,4503 ****
--- 4524,4532 ----
        set_gdbarch_long_bit (gdbarch, 32);
        set_gdbarch_ptr_bit (gdbarch, 32);
        set_gdbarch_long_long_bit (gdbarch, 64);
+       /* Set up reg_struct_has_addr.  */
+       set_gdbarch_reg_struct_has_addr (gdbarch, 
+ 				       mips_eabi_reg_struct_has_addr);
        break;
      case MIPS_ABI_EABI64:
        tdep->mips_default_saved_regsize = 8;
*************** mips_gdbarch_init (struct gdbarch_info i
*** 4511,4516 ****
--- 4540,4548 ----
        set_gdbarch_long_bit (gdbarch, 64);
        set_gdbarch_ptr_bit (gdbarch, 64);
        set_gdbarch_long_long_bit (gdbarch, 64);
+       /* Set up reg_struct_has_addr.  */
+       set_gdbarch_reg_struct_has_addr (gdbarch, 
+ 				       mips_eabi_reg_struct_has_addr);
        break;
      case MIPS_ABI_N32:
        tdep->mips_default_saved_regsize = 4;
*************** mips_gdbarch_init (struct gdbarch_info i
*** 4535,4540 ****
--- 4567,4575 ----
  	tm_print_insn_info.mach = info.bfd_arch_info->mach;
        else
  	tm_print_insn_info.mach = bfd_mach_mips8000;
+       /* Set up reg_struct_has_addr.  */
+       set_gdbarch_reg_struct_has_addr (gdbarch, 
+ 				       mips_newabi_reg_struct_has_addr);
        break;
      case MIPS_ABI_N64:
        tdep->mips_default_saved_regsize = 8;
*************** mips_gdbarch_init (struct gdbarch_info i
*** 4559,4564 ****
--- 4594,4602 ----
  	tm_print_insn_info.mach = info.bfd_arch_info->mach;
        else
  	tm_print_insn_info.mach = bfd_mach_mips8000;
+       /* Set up reg_struct_has_addr.  */
+       set_gdbarch_reg_struct_has_addr (gdbarch, 
+ 				       mips_newabi_reg_struct_has_addr);
        break;
      default:
        internal_error (__FILE__, __LINE__,

Re: [RFA] mips-n32 reg_struct_has_addr

[Andrew Cagney]

> + static int
> + mips_newabi_reg_struct_has_addr (int gcc_p, struct type *type)
> + {
> +   enum type_code typecode = TYPE_CODE (check_typedef (type));
> +   int len = TYPE_LENGTH (check_typedef (type));
> + 
> +   if (typecode == TYPE_CODE_STRUCT   || typecode == TYPE_CODE_UNION)
> +     return (len > MIPS_SAVED_REGSIZE && len % MIPS_SAVED_REGSIZE != 0);
> + 
> +   return 0;
> + }

No, I don't think this is right.  As best I can tell, there is no cap on 
the size of a struct that is passed by register.

http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/srch3@o32/0650/bks/SGI_Developer/books/Mpro_n32_ABI/sgi_html/ch02.html#id80931

I.e., o32 and n32/n64 are the same -> never pass structures by reference.

> *************** mips_push_arguments (int nargs,
> *** 2428,2448 ****
>   			    "mips_push_arguments: %d len=%d type=%d",
>   			    argnum + 1, len, (int) typecode);
>   
> !       /* The EABI passes structures that do not fit in a register by

Per other e-mail, rather than modify the existing mips_push_argument() 
can you please created a dedicated mips_n32n64_push-arguments() function 
and hack on that.  That way, I don't have to worry about the other ABIs.

> +       /* Set up reg_struct_has_addr.  */
> +       set_gdbarch_reg_struct_has_addr (gdbarch, 

BTW, the comment here is redundant.

enjoy,
Andrew

Re: [RFA] mips-n32 reg_struct_has_addr

[Michael Snyder]

Andrew Cagney wrote:
> 
> > + static int
> > + mips_newabi_reg_struct_has_addr (int gcc_p, struct type *type)
> > + {
> > +   enum type_code typecode = TYPE_CODE (check_typedef (type));
> > +   int len = TYPE_LENGTH (check_typedef (type));
> > +
> > +   if (typecode == TYPE_CODE_STRUCT   || typecode == TYPE_CODE_UNION)
> > +     return (len > MIPS_SAVED_REGSIZE && len % MIPS_SAVED_REGSIZE != 0);
> > +
> > +   return 0;
> > + }
> 
> No, I don't think this is right.  As best I can tell, there is no cap on
> the size of a struct that is passed by register.
> 
> http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/srch3@o32/0650/bks/SGI_Developer/books/Mpro_n32_ABI/sgi_html/ch02.html#id80931
> 
> I.e., o32 and n32/n64 are the same -> never pass structures by reference.
> 
> > *************** mips_push_arguments (int nargs,
> > *** 2428,2448 ****
> >                           "mips_push_arguments: %d len=%d type=%d",
> >                           argnum + 1, len, (int) typecode);
> >
> > !       /* The EABI passes structures that do not fit in a register by
> 
> Per other e-mail, rather than modify the existing mips_push_argument()
> can you please created a dedicated mips_n32n64_push-arguments() function
> and hack on that.  That way, I don't have to worry about the other ABIs.
> 
> > +       /* Set up reg_struct_has_addr.  */
> > +       set_gdbarch_reg_struct_has_addr (gdbarch,
> 
> BTW, the comment here is redundant.
> 
> enjoy,
> Andrew

Re: [RFA] mips-n32 reg_struct_has_addr

[Michael Snyder]

Andrew Cagney wrote:
> 
> > + static int
> > + mips_newabi_reg_struct_has_addr (int gcc_p, struct type *type)
> > + {
> > +   enum type_code typecode = TYPE_CODE (check_typedef (type));
> > +   int len = TYPE_LENGTH (check_typedef (type));
> > +
> > +   if (typecode == TYPE_CODE_STRUCT   || typecode == TYPE_CODE_UNION)
> > +     return (len > MIPS_SAVED_REGSIZE && len % MIPS_SAVED_REGSIZE != 0);
> > +
> > +   return 0;
> > + }
> 
> No, I don't think this is right.  As best I can tell, there is no cap on
> the size of a struct that is passed by register.
> 
> http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/srch3@o32/0650/bks/SGI_Developer/books/Mpro_n32_ABI/sgi_html/ch02.html#id80931
> 
> I.e., o32 and n32/n64 are the same -> never pass structures by reference.

OK, patch withdrawn, I will resubmit it using this assumption, 
just to get the gdbarch-ification checked in, and then we can
work on resolving how N32/64 should work.


> 
> > *************** mips_push_arguments (int nargs,
> > *** 2428,2448 ****
> >                           "mips_push_arguments: %d len=%d type=%d",
> >                           argnum + 1, len, (int) typecode);
> >
> > !       /* The EABI passes structures that do not fit in a register by
> 
> Per other e-mail, rather than modify the existing mips_push_argument()
> can you please created a dedicated mips_n32n64_push-arguments() function
> and hack on that.  That way, I don't have to worry about the other ABIs.
> 
> > +       /* Set up reg_struct_has_addr.  */
> > +       set_gdbarch_reg_struct_has_addr (gdbarch,
> 
> BTW, the comment here is redundant.
> 
> enjoy,
> Andrew

Re: [RFA] mips-n32 reg_struct_has_addr

[Andrew Cagney]

> No, I don't think this is right.  As best I can tell, there is no cap on
>> the size of a struct that is passed by register.
>> 
>> http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/srch3@o32/0650/bks/SGI_Developer/books/Mpro_n32_ABI/sgi_html/ch02.html#id80931
>> 
>> I.e., o32 and n32/n64 are the same -> never pass structures by reference.
> 
> 
> OK, patch withdrawn, I will resubmit it using this assumption, 
> just to get the gdbarch-ification checked in, and then we can
> work on resolving how N32/64 should work.

Thanks!

BTW, if you're trying to test this, DO NOT TRUST GCC!  Check things out 
with an SGI compiler.

Andrew