[ping] Re: [RFA] sh-tdep: multi-arch the push_dummy_call method.

[Michael Snyder <msnyder at redhat dot com>]

Michael Snyder wrote:

> Elena, this splits off two versions of push_dummy_call: one for sh2e,
> sh3e, and sh4, and the other for all the others.  There are two 
> differences:
> how they pass floats, and how they pass large structs.
>
> This wins us 6 new passes in call-ar-st, one in call-rt-st, 13 in 
> callfuncs,
> and one in varargs.
>
>
>
> ------------------------------------------------------------------------
>
> 2003-07-30  Michael Snyder  <msnyder@redhat.com>
>
> 	* sh-tdep.h (struct gdbarch_tdep): New member FLOAT_ARGLAST_REG.
> 	* sh-tdep.c (sh_gdbarch_init): For sh2e, sh3e, and sh4, set 
> 	FLOAT_ARG0_REGNUM and FLOAT_ARGLAST_REGNUM, to be used for 
> 	argument passing.
> 	(sh_push_dummy_call_fpu, sh_push_dummy_call_nofpu): New 
> 	functions, replace sh_push_dummy_call.
> 	(sh_gdbarch_init): Set push_dummy_call to one of new methods.
>
> Index: sh-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/sh-tdep.c,v
> retrieving revision 1.135
> diff -p -r1.135 sh-tdep.c
> *** sh-tdep.c	1 Aug 2003 19:52:49 -0000	1.135
> --- sh-tdep.c	1 Aug 2003 22:00:40 -0000
> *************** sh_frame_align (struct gdbarch *ignore, 
> *** 2034,2040 ****
>    return sp & ~3;
>  }
>  
> ! /* Function: push_arguments
>     Setup the function arguments for calling a function in the inferior.
>  
>     On the Hitachi SH architecture, there are four registers (R4 to R7)
> --- 2034,2040 ----
>    return sp & ~3;
>  }
>  
> ! /* Function: sh_push_dummy_call (formerly push_arguments)
>     Setup the function arguments for calling a function in the inferior.
>  
>     On the Hitachi SH architecture, there are four registers (R4 to R7)
> *************** sh_frame_align (struct gdbarch *ignore, 
> *** 2042,2047 ****
> --- 2042,2051 ----
>     four arguments (depending on size) may go into these registers.
>     The rest go on the stack.
>  
> +    MVS: Except on SH variants that have floating point registers.
> +    In that case, float and double arguments are passed in the same
> +    manner, but using FP registers instead of GP registers.
> + 
>     Arguments that are smaller than 4 bytes will still take up a whole
>     register or a whole 32-bit word on the stack, and will be 
>     right-justified in the register or the stack word.  This includes
> *************** sh_frame_align (struct gdbarch *ignore, 
> *** 2055,2060 ****
> --- 2059,2069 ----
>     that will be passed in this way; in other words, the convention of 
>     passing a pointer to a large aggregate instead of a copy is not used.
>  
> +    MVS: The above appears to be true for the SH variants that do not
> +    have an FPU, however those that have an FPU appear to copy the 
> +    aggregate argument onto the stack (and not place it in registers)
> +    if it is larger than 16 bytes (four GP registers).
> + 
>     An exceptional case exists for struct arguments (and possibly other
>     aggregates such as arrays) if the size is larger than 4 bytes but 
>     not a multiple of 4 bytes.  In this case the argument is never split 
> *************** sh_frame_align (struct gdbarch *ignore, 
> *** 2078,2088 ****
>     to R7.   */
>  
>  static CORE_ADDR
> ! sh_push_dummy_call (struct gdbarch *gdbarch, CORE_ADDR func_addr,
> ! 		    struct regcache *regcache, CORE_ADDR bp_addr, int nargs,
> ! 		    struct value **args, CORE_ADDR sp, int struct_return,
> ! 		    CORE_ADDR struct_addr)
>  
>  {
>    int stack_offset, stack_alloc;
>    int argreg;
> --- 2087,2210 ----
>     to R7.   */
>  
>  static CORE_ADDR
> ! sh_push_dummy_call_fpu (struct gdbarch *gdbarch, 
> ! 			CORE_ADDR func_addr,
> ! 			struct regcache *regcache, 
> ! 			CORE_ADDR bp_addr, int nargs,
> ! 			struct value **args, 
> ! 			CORE_ADDR sp, int struct_return,
> ! 			CORE_ADDR struct_addr)
> ! {
> !   int stack_offset, stack_alloc;
> !   int argreg, flt_argreg;
> !   int argnum;
> !   struct type *type;
> !   CORE_ADDR regval;
> !   char *val;
> !   char valbuf[4];
> !   int len;
> !   int odd_sized_struct;
> !   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 
> ! 
> !   /* first force sp to a 4-byte alignment */
> !   sp = sh_frame_align (gdbarch, sp);
> ! 
> !   /* The "struct return pointer" pseudo-argument has its own dedicated 
> !      register */
> !   if (struct_return)
> !     regcache_cooked_write_unsigned (regcache, 
> ! 				    STRUCT_RETURN_REGNUM, 
> ! 				    struct_addr);
> ! 
> !   /* Now make sure there's space on the stack */
> !   for (argnum = 0, stack_alloc = 0; argnum < nargs; argnum++)
> !     stack_alloc += ((TYPE_LENGTH (VALUE_TYPE (args[argnum])) + 3) & ~3);
> !   sp -= stack_alloc;		/* make room on stack for args */
> ! 
> !   /* Now load as many as possible of the first arguments into
> !      registers, and push the rest onto the stack.  There are 16 bytes
> !      in four registers available.  Loop thru args from first to last.  */
> ! 
> !   argreg = tdep->ARG0_REGNUM;
> !   flt_argreg = tdep->FLOAT_ARG0_REGNUM;
> !   for (argnum = 0, stack_offset = 0; argnum < nargs; argnum++)
> !     {
> !       type = VALUE_TYPE (args[argnum]);
> !       len = TYPE_LENGTH (type);
> !       memset (valbuf, 0, sizeof (valbuf));
> !       if (len < 4)
> ! 	{
> ! 	  /* value gets right-justified in the register or stack word */
> ! 	  if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
> ! 	    memcpy (valbuf + (4 - len),
> ! 		    (char *) VALUE_CONTENTS (args[argnum]), len);
> ! 	  else
> ! 	    memcpy (valbuf, (char *) VALUE_CONTENTS (args[argnum]), len);
> ! 	  val = valbuf;
> ! 	}
> !       else
> ! 	val = (char *) VALUE_CONTENTS (args[argnum]);
>  
> +       if (len > 4 && (len & 3) != 0)
> + 	odd_sized_struct = 1;	/* Such structs go entirely on stack.  */
> +       else if (len > 16)
> + 	odd_sized_struct = 1;	/* So do aggregates bigger than 4 words.  */
> +       else
> + 	odd_sized_struct = 0;
> +       while (len > 0)
> + 	{
> + 	  if ((TYPE_CODE (type) == TYPE_CODE_FLT 
> + 	       && flt_argreg > tdep->FLOAT_ARGLAST_REGNUM) 
> + 	      || argreg > tdep->ARGLAST_REGNUM
> + 	      || odd_sized_struct)
> + 	    {			
> + 	      /* must go on the stack */
> + 	      write_memory (sp + stack_offset, val, 4);
> + 	      stack_offset += 4;
> + 	    }
> + 	  /* NOTE WELL!!!!!  This is not an "else if" clause!!!
> + 	     That's because some *&^%$ things get passed on the stack
> + 	     AND in the registers!   */
> + 	  if (TYPE_CODE (type) == TYPE_CODE_FLT &&
> + 	      flt_argreg > 0 && flt_argreg <= tdep->FLOAT_ARGLAST_REGNUM)
> + 	    {
> + 	      /* Argument goes in a single-precision fp reg.  */
> + 	      regval = extract_unsigned_integer (val, register_size (gdbarch,
> + 								     argreg));
> + 	      regcache_cooked_write_unsigned (regcache, flt_argreg++, regval);
> + 	    }
> + 	  else if (argreg <= tdep->ARGLAST_REGNUM)
> + 	    {			
> + 	      /* there's room in a register */
> + 	      regval = extract_unsigned_integer (val, register_size (gdbarch,
> + 								     argreg));
> + 	      regcache_cooked_write_unsigned (regcache, argreg++, regval);
> + 	    }
> + 	  /* Store the value 4 bytes at a time.  This means that things
> + 	     larger than 4 bytes may go partly in registers and partly
> + 	     on the stack.  */
> + 	  len -= register_size (gdbarch, argreg);
> + 	  val += register_size (gdbarch, argreg);
> + 	}
> +     }
> + 
> +   /* Store return address. */
> +   regcache_cooked_write_unsigned (regcache, tdep->PR_REGNUM, bp_addr);
> + 
> +   /* Update stack pointer.  */
> +   regcache_cooked_write_unsigned (regcache, SP_REGNUM, sp);
> + 
> +   return sp;
> + }
> + 
> + static CORE_ADDR
> + sh_push_dummy_call_nofpu (struct gdbarch *gdbarch, 
> + 			  CORE_ADDR func_addr,
> + 			  struct regcache *regcache, 
> + 			  CORE_ADDR bp_addr, 
> + 			  int nargs, struct value **args, 
> + 			  CORE_ADDR sp, int struct_return, 
> + 			  CORE_ADDR struct_addr)
>  {
>    int stack_offset, stack_alloc;
>    int argreg;
> *************** sh_push_dummy_call (struct gdbarch *gdba
> *** 2101,2107 ****
>    /* The "struct return pointer" pseudo-argument has its own dedicated 
>       register */
>    if (struct_return)
> !     regcache_cooked_write_unsigned (regcache, STRUCT_RETURN_REGNUM, struct_addr);
>  
>    /* Now make sure there's space on the stack */
>    for (argnum = 0, stack_alloc = 0; argnum < nargs; argnum++)
> --- 2223,2231 ----
>    /* The "struct return pointer" pseudo-argument has its own dedicated 
>       register */
>    if (struct_return)
> !     regcache_cooked_write_unsigned (regcache, 
> ! 				    STRUCT_RETURN_REGNUM, 
> ! 				    struct_addr);
>  
>    /* Now make sure there's space on the stack */
>    for (argnum = 0, stack_alloc = 0; argnum < nargs; argnum++)
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4374,4380 ****
>        set_gdbarch_push_dummy_code (gdbarch, sh_push_dummy_code);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>  
>        set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, sh_nofp_frame_init_saved_regs);
> --- 4498,4504 ----
>        set_gdbarch_push_dummy_code (gdbarch, sh_push_dummy_code);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_nofpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>  
>        set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, sh_nofp_frame_init_saved_regs);
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4387,4393 ****
>        set_gdbarch_push_dummy_code (gdbarch, sh_push_dummy_code);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>  
>        set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, sh_nofp_frame_init_saved_regs);
> --- 4511,4517 ----
>        set_gdbarch_push_dummy_code (gdbarch, sh_push_dummy_code);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_nofpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>  
>        set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, sh_nofp_frame_init_saved_regs);
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4404,4416 ****
>        set_gdbarch_fp0_regnum (gdbarch, 25);
>        set_gdbarch_store_return_value (gdbarch, sh3e_sh4_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh3e_sh4_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->FPUL_REGNUM = 23;
>        tdep->FPSCR_REGNUM = 24;
>        tdep->FP_LAST_REGNUM = 40;
>  
> !       set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, sh_nofp_frame_init_saved_regs);
>        break;
>      case bfd_mach_sh_dsp:
>        set_gdbarch_register_name (gdbarch, sh_sh_dsp_register_name);
> --- 4528,4543 ----
>        set_gdbarch_fp0_regnum (gdbarch, 25);
>        set_gdbarch_store_return_value (gdbarch, sh3e_sh4_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh3e_sh4_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_fpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->FPUL_REGNUM = 23;
>        tdep->FPSCR_REGNUM = 24;
>        tdep->FP_LAST_REGNUM = 40;
> +       tdep->FLOAT_ARG0_REGNUM = 29;	/* FIXME use constants! */
> +       tdep->FLOAT_ARGLAST_REGNUM = 36;	/* FIXME use constants! */
>  
> !       set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, 
> ! 						    sh_nofp_frame_init_saved_regs);
>        break;
>      case bfd_mach_sh_dsp:
>        set_gdbarch_register_name (gdbarch, sh_sh_dsp_register_name);
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4421,4427 ****
>        set_gdbarch_register_sim_regno (gdbarch, sh_dsp_register_sim_regno);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->DSR_REGNUM = 24;
>        tdep->A0G_REGNUM = 25;
> --- 4548,4554 ----
>        set_gdbarch_register_sim_regno (gdbarch, sh_dsp_register_sim_regno);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_nofpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->DSR_REGNUM = 24;
>        tdep->A0G_REGNUM = 25;
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4448,4454 ****
>        set_gdbarch_push_dummy_code (gdbarch, sh_push_dummy_code);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->SSR_REGNUM = 41;
>        tdep->SPC_REGNUM = 42;
> --- 4575,4581 ----
>        set_gdbarch_push_dummy_code (gdbarch, sh_push_dummy_code);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_nofpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->SSR_REGNUM = 41;
>        tdep->SPC_REGNUM = 42;
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4467,4477 ****
>        set_gdbarch_fp0_regnum (gdbarch, 25);
>        set_gdbarch_store_return_value (gdbarch, sh3e_sh4_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh3e_sh4_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->FPUL_REGNUM = 23;
>        tdep->FPSCR_REGNUM = 24;
>        tdep->FP_LAST_REGNUM = 40;
>        tdep->SSR_REGNUM = 41;
>        tdep->SPC_REGNUM = 42;
>  
> --- 4594,4606 ----
>        set_gdbarch_fp0_regnum (gdbarch, 25);
>        set_gdbarch_store_return_value (gdbarch, sh3e_sh4_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh3e_sh4_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_fpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->FPUL_REGNUM = 23;
>        tdep->FPSCR_REGNUM = 24;
>        tdep->FP_LAST_REGNUM = 40;
> +       tdep->FLOAT_ARG0_REGNUM = 29;	/* FIXME use constants! */
> +       tdep->FLOAT_ARGLAST_REGNUM = 36;	/* FIXME use constants! */
>        tdep->SSR_REGNUM = 41;
>        tdep->SPC_REGNUM = 42;
>  
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4486,4492 ****
>        set_gdbarch_register_sim_regno (gdbarch, sh_dsp_register_sim_regno);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->DSR_REGNUM = 24;
>        tdep->A0G_REGNUM = 25;
> --- 4615,4621 ----
>        set_gdbarch_register_sim_regno (gdbarch, sh_dsp_register_sim_regno);
>        set_gdbarch_store_return_value (gdbarch, sh_default_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh_default_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_nofpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->DSR_REGNUM = 24;
>        tdep->A0G_REGNUM = 25;
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4519,4525 ****
>        set_gdbarch_pseudo_register_write (gdbarch, sh_pseudo_register_write);
>        set_gdbarch_store_return_value (gdbarch, sh3e_sh4_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh3e_sh4_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->FPUL_REGNUM = 23;
>        tdep->FPSCR_REGNUM = 24;
> --- 4648,4654 ----
>        set_gdbarch_pseudo_register_write (gdbarch, sh_pseudo_register_write);
>        set_gdbarch_store_return_value (gdbarch, sh3e_sh4_store_return_value);
>        set_gdbarch_extract_return_value (gdbarch, sh3e_sh4_extract_return_value);
> !       set_gdbarch_push_dummy_call (gdbarch, sh_push_dummy_call_fpu);
>        set_gdbarch_extract_struct_value_address (gdbarch, sh_extract_struct_value_address);
>        tdep->FPUL_REGNUM = 23;
>        tdep->FPSCR_REGNUM = 24;
> *************** sh_gdbarch_init (struct gdbarch_info inf
> *** 4530,4535 ****
> --- 4659,4666 ----
>        tdep->DR_LAST_REGNUM = 66;
>        tdep->FV0_REGNUM = 67;
>        tdep->FV_LAST_REGNUM = 70;
> +       tdep->FLOAT_ARG0_REGNUM = 29;	/* FIXME use constants! */
> +       tdep->FLOAT_ARGLAST_REGNUM = 36;	/* FIXME use constants! */
>  
>        set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, sh_fp_frame_init_saved_regs);
>        break;
> Index: sh-tdep.h
> ===================================================================
> RCS file: /cvs/src/src/gdb/sh-tdep.h,v
> retrieving revision 1.3
> diff -p -r1.3 sh-tdep.h
> *** sh-tdep.h	4 Jan 2003 23:38:45 -0000	1.3
> --- sh-tdep.h	1 Aug 2003 22:00:40 -0000
> *************** struct gdbarch_tdep
> *** 85,91 ****
>      int FV_LAST_C_REGNUM; /*                            sh5-compact*/
>      int ARG0_REGNUM;
>      int ARGLAST_REGNUM;
> !     int FLOAT_ARGLAST_REGNUM;
>      int RETURN_REGNUM;
>      enum sh_abi sh_abi;
>    };
> --- 85,92 ----
>      int FV_LAST_C_REGNUM; /*                            sh5-compact*/
>      int ARG0_REGNUM;
>      int ARGLAST_REGNUM;
> !     int FLOAT_ARG0_REGNUM;	/* sh4 */
> !     int FLOAT_ARGLAST_REGNUM;	/* sh4, sh5 */
>      int RETURN_REGNUM;
>      enum sh_abi sh_abi;
>    };
>