RFC: fix bug in DW_OP_GNU_implicit_pointer

[Tom Tromey]

Tom> 2012-11-30  Tom Tromey  <tromey@redhat.com>
Tom> 	* dwarf2read.c (dwarf2_fetch_die_loc_sect_off): New function.
Tom> 	(dwarf2_fetch_die_loc_cu_off): Rename from
Tom> 	dwarf2_fetch_die_location_block.  Rewrite to use
Tom> 	dwarf2_fetch_die_loc_sect_off.
Tom> 	* dwarf2loc.h (dwarf2_fetch_die_loc_sect_off): Declare.
Tom> 	(dwarf2_fetch_die_loc_cu_off): Rename.
Tom> 	* dwarf2loc.c (indirect_pieced_value): Use
Tom> 	dwarf2_fetch_die_loc_sect_off.
Tom> 	* dwarf2expr.h (struct dwarf_expr_context) <len, data>: Update
Tom> 	comment.
Tom> 	(struct dwarf_expr_piece) <v.ptr.die>: Now a sect_offset.
Tom> 	* dwarf2expr.c (add_piece): Update.
Tom> 	(execute_stack_op) <DW_OP_GNU_implicit_pointer>: Update comment.

Tom> 2012-11-30  Tom Tromey  <tromey@redhat.com>
Tom> 	* gdb.dwarf2/implptr-64bit.exp: Run tests with two CUs as well.
Tom> 	(test): Add "two_cu" argument.
Tom> 	* gdb.dwarf2/implptr-64bit.S: Move subprogram later; use ref_addr
Tom> 	for types; allow two CUs.

I'm checking this in now.

Tom