gdb/

gdb/
	Fix DW_OP_GNU_implicit_pointer for DWARF32 v3+ on 64-bit arches.
	* dwarf2-frame.c (execute_stack_op): Initialize ctx->ref_addr_size.
	* dwarf2expr.c (execute_stack_op) <DW_OP_GNU_implicit_pointer>: Use
	ctx->ref_addr_size.  Handle its invalid value.
	* dwarf2expr.h (struct dwarf_expr_context): New field ref_addr_size.
	* dwarf2loc.c (dwarf2_evaluate_loc_desc_full)
	(dwarf2_loc_desc_needs_frame): Initialize ctx->ref_addr_size.
	* dwarf2loc.h (dwarf2_per_cu_ref_addr_size): New declaration.
	* dwarf2read.c (decode_locdesc): Initialize ctx->ref_addr_size.
	(dwarf2_per_cu_ref_addr_size): New function.

gdb/testsuite/
	Fix DW_OP_GNU_implicit_pointer for DWARF32 v3+ on 64-bit arches.
	* gdb.dwarf2/implptr-64bit.S: New file.
	* gdb.dwarf2/implptr-64bit.exp: New file.