PR debug/28767
	PR debug/56974
	* langhooks.h (struct lang_hooks_for_types): Add type_dwarf_attribute
	langhook.
	* langhooks.c (lhd_type_dwarf_attribute): New function.
	* langhooks-def.h (lhd_type_dwarf_attribute): Declare.
	(LANG_HOOKS_TYPE_DWARF_ATTRIBUTE): Define.
	(LANG_HOOKS_FOR_TYPES_INITIALIZER): Add
	LANG_HOOKS_TYPE_DWARF_ATTRIBUTE.
	(check_qualified_type, check_aligned_type): Call it.
	* dwarf2out.c (modified_type_die): Don't use type_main_variant
	for FUNCTION_TYPE or METHOD_TYPE, instead walk over variants with
	check_base_type and check_lang_type.
	(gen_ptr_to_mbr_type_die): If lookup_type_die is already non-NULL,
	return early.  For pointer-to-data-member add DW_AT_use_location
	attribute.
	(gen_subroutine_type_die): Add DW_AT_{,rvalue_}reference attribute
	if needed.
	(gen_type_die_with_usage): Don't use type_main_variant
	for FUNCTION_TYPE or METHOD_TYPE, instead walk over variants with
	check_base_type and check_lang_type.  Formatting fixes. Call
	get_debug_type langhook.
cp/
	* tree.c (cp_check_qualified_type): Use check_base_type and
	TYPE_QUALS comparison instead of check_qualified_type.
	(cxx_type_hash_eq): Return false if type_memfn_rqual don't match.
	* cp-objcp-common.c (cp_get_debug_type): New function.
	(cp_decl_dwarf_attribute): Don't handle types here.
	(cp_type_dwarf_attribute): New function.
	* cp-objcp-common.h (cp_get_debug_type, cp_type_dwarf_attribute):
	Declare.
	(LANG_HOOKS_GET_DEBUG_TYPE, LANG_HOOKS_TYPE_DWARF_ATTRIBUTE):
	Define.
testsuite/
	* g++.dg/debug/dwarf2/ptrdmem-1.C: New test.
	* g++.dg/debug/dwarf2/ref-3.C: New test.
	* g++.dg/debug/dwarf2/ref-4.C: New test.
	* g++.dg/debug/dwarf2/refqual-1.C: New test.
	* g++.dg/debug/dwarf2/refqual-2.C: New test.

From-SVN: r241832