[RFC/PATCH]: DWARF2_REG_TO_REGNUM

[Michael Snyder <msnyder at redhat dot com>]

This patch supplements Andrew's patch to multi-arch the several macros
that translate between a GCC register number and a GDB register number.
The dwarf2 reader will pick up register numbers from the compiler that
are associated with the storage locations of variables.  The new macro
DWARF2_REG_TO_REGNUM will translate those register numbers into the ones
that GDB uses to identify a register.  If undefined, it will default to
identity.

	* dwarf2read.c (DWARF2_REG_TO_REGNUM): New macro.  Default to identity.
	(new_symbol): Use DWARF2_REG_TO_REGNUM) to translate the register id
	associated with a register variable, basereg, frame pointer, etc.
*** /home/msnyder/sourceware/src/gdb/dwarf2read.c	Tue Nov  7 18:50:51 2000
--- ./dwarf2read.c	Sun Dec  3 12:14:36 2000
***************
*** 43,48 ****
--- 43,52 ----
  #include "gdb_string.h"
  #include <sys/types.h>
  
+ #ifndef DWARF2_REG_TO_REGNUM
+ #define DWARF2_REG_TO_REGNUM(REG) (REG)
+ #endif
+ 
  #if 0
  /* .debug_info header for a compilation unit
     Because of alignment constraints, this structure has padding and cannot
*************** new_symbol (struct die_info *die, struct
*** 4201,4211 ****
  		  else if (isreg)
  		    {
  		      SYMBOL_CLASS (sym) = LOC_REGISTER;
  		    }
  		  else if (offreg)
  		    {
  		      SYMBOL_CLASS (sym) = LOC_BASEREG;
! 		      SYMBOL_BASEREG (sym) = basereg;
  		    }
  		  else if (islocal)
  		    {
--- 4205,4217 ----
  		  else if (isreg)
  		    {
  		      SYMBOL_CLASS (sym) = LOC_REGISTER;
+ 		      SYMBOL_VALUE (sym) = 
+ 			DWARF2_REG_TO_REGNUM (SYMBOL_VALUE (sym));
  		    }
  		  else if (offreg)
  		    {
  		      SYMBOL_CLASS (sym) = LOC_BASEREG;
! 		      SYMBOL_BASEREG (sym) = DWARF2_REG_TO_REGNUM (basereg);
  		    }
  		  else if (islocal)
  		    {
*************** new_symbol (struct die_info *die, struct
*** 4247,4252 ****
--- 4253,4260 ----
  	      if (isreg)
  		{
  		  SYMBOL_CLASS (sym) = LOC_REGPARM;
+ 		  SYMBOL_VALUE (sym) = 
+ 		    DWARF2_REG_TO_REGNUM (SYMBOL_VALUE (sym));
  		}
  	      else if (offreg)
  		{
*************** new_symbol (struct die_info *die, struct
*** 4259,4265 ****
  		  else
  		    {
  		      SYMBOL_CLASS (sym) = LOC_BASEREG_ARG;
! 		      SYMBOL_BASEREG (sym) = basereg;
  		    }
  		}
  	      else
--- 4267,4273 ----
  		  else
  		    {
  		      SYMBOL_CLASS (sym) = LOC_BASEREG_ARG;
! 		      SYMBOL_BASEREG (sym) = DWARF2_REG_TO_REGNUM (basereg);
  		    }
  		}
  	      else