[commit] Yet another get_frame_arch (NULL) call

[Ulrich Weigand]

Hello,

we found another case where get_frame_arch (NULL) was called:
dwarf2_evaluate_loc_desc may be called either for frame-local
variables (in which case it receives a pointer to a frame_info
struct), or for global variables (in which case that pointer
is NULL).

However, the routine currently always calls get_frame_arch on
the pointer it receives -- this is broken in the second case.
The fix is to move the get_frame_arch call down into those
places where the architecture is actually needed, that is for
variables located in registers.  (In those cases, we must have
a non-NULL frame, because the dwarf2_loc_desc_needs_frame will
have returned true.)

Tested with no regressions on powerpc-linux.
Committed to mainline.

Bye,
Ulrich


ChangeLog:

	* dwarf2loc.c (dwarf2_evaluate_loc_desc): Do not call get_frame_arch
	for NULL frame pointers.

Index: gdb/dwarf2loc.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2loc.c,v
retrieving revision 1.53
diff -c -p -r1.53 dwarf2loc.c
*** gdb/dwarf2loc.c	3 Jan 2009 05:57:51 -0000	1.53
--- gdb/dwarf2loc.c	13 Jan 2009 17:51:38 -0000
*************** dwarf2_evaluate_loc_desc (struct symbol 
*** 199,205 ****
  			  gdb_byte *data, unsigned short size,
  			  struct dwarf2_per_cu_data *per_cu)
  {
-   struct gdbarch *arch = get_frame_arch (frame);
    struct value *retval;
    struct dwarf_expr_baton baton;
    struct dwarf_expr_context *ctx;
--- 199,204 ----
*************** dwarf2_evaluate_loc_desc (struct symbol 
*** 238,246 ****
  	  struct dwarf_expr_piece *p = &ctx->pieces[i];
  	  if (p->in_reg)
  	    {
  	      bfd_byte regval[MAX_REGISTER_SIZE];
! 	      int gdb_regnum = gdbarch_dwarf2_reg_to_regnum
! 				 (arch, p->value);
  	      get_frame_register (frame, gdb_regnum, regval);
  	      memcpy (contents + offset, regval, p->size);
  	    }
--- 237,245 ----
  	  struct dwarf_expr_piece *p = &ctx->pieces[i];
  	  if (p->in_reg)
  	    {
+ 	      struct gdbarch *arch = get_frame_arch (frame);
  	      bfd_byte regval[MAX_REGISTER_SIZE];
! 	      int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->value);
  	      get_frame_register (frame, gdb_regnum, regval);
  	      memcpy (contents + offset, regval, p->size);
  	    }
*************** dwarf2_evaluate_loc_desc (struct symbol 
*** 253,261 ****
      }
    else if (ctx->in_reg)
      {
        CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0);
!       int gdb_regnum = gdbarch_dwarf2_reg_to_regnum
! 			 (arch, dwarf_regnum);
        retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame);
      }
    else
--- 252,260 ----
      }
    else if (ctx->in_reg)
      {
+       struct gdbarch *arch = get_frame_arch (frame);
        CORE_ADDR dwarf_regnum = dwarf_expr_fetch (ctx, 0);
!       int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum);
        retval = value_from_register (SYMBOL_TYPE (var), gdb_regnum, frame);
      }
    else
-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com