PR middle-end/21275
	PR middle-end/21766
	* target.h (struct gcc_target): Add valid_dllimport_attribute_p
	target hook.
	(struct cxx): Add adjust_class_at_definition target hook.
	* target-def.h: (TARGET_VALID_DLLIMPORT_ATTRIBUTE_P): New define,
	defaulting to hook_bool_tree_true. Add to TARGET_INITIALIZER
	(TARGET_CXX_ADJUST_CLASS_AT_DEFINITION): New define, defaulting to
	hook_void_tree. Add to TARGET_CXX.
	* tree.h (struct decl_with_vis): Rename non_addr_const_p field to
	dllimport_flag.
	(DECL_NON_ADDR_CONSTANT_P): Replace with DECL_DLLIMPORT_P macro.
	* tree.c (merge_dllimport_decl_attributes): Check DECL_DLLIMPORT_P
	instead of attribute. Check for dllexport override.  Warn if
	inconsistent dll linkage. Don't lose old dllimport if decl has
	had address referenced.   Tweak lookup of dllimport atribute.
	(handle_dll_attribute): Check targetm.valid_dllimport_attribute_p
	for target specific rules.  Don't add dllimport attribute if
	DECL_DECLARED_INLINE_P.  Set DECL_DLLIMPORT_P when adding
	dllimport attribute.
	(staticp): Replace DECL_NON_ADDR_CONSTANT_P with DECL_DLLIMPORT_P.
	* varasm.c (initializer_constant_valid_p): Replace
	DECL_NON_ADDR_CONSTANT_P with DECL_DLLIMPORT_P

	PR target/21801
	PR target/23589
	* config.gcc (i[34567]86-*-cygwin*): Add winnt-cxx.o to
	'cxx_target_objs', winnt-stubs,o to 'extra_objs'.
	(i[34567]86-*-mingw32*): Likewise.

	* doc/tm.texi (TARGET_CXX_ADJUST_CLASS_AT_DEFINITION): Document.
	(TARGET_VALID_DLLIMPORT_ATTRIBUTE_P): Document.

	* config/i386/winnt.c (i386_pe_dllimport_p): Factor out
	C++-specific code. Change return value to bool.
	(i386_pe_dllimport_p): Likewise.
	(associated_type): Simplify and make language-independent
	(i386_pe_encode_section_info): Replace override of ambiguous
	dllimport symbol refs with a gcc_assert.
	(i386_pe_valid_dllimport_attribute_p): Define.
	* config/i386/winnt-cxx.c: New file. Define C++ versions of
	i386_pe_type_dllimport_p, i386_pe_type_dllexport_p,
	i386_pe_adjust_class_at_definition.
	* config/i386/winnt-stubs.c: New file. Define stub versions of
	lang-specific functions.
	* config/i386/i386-protos.h: Declare winnt-[cxx|stubs].c functions
	i386_pe_type_dllimport_p, i386_pe_type_dllexport_p,
	i386_pe_adjust_class_at_definition.
	(i386_pe_valid_dllimport_attribute_p): Declare.
	* config/i386/cygming.h (TARGET_VALID_DLLIMPORT_ATTRIBUTE_P): Define.
	(TARGET_CXX_ADJUST_CLASS_AT_DEFINITION): Define.
	* config/i386/t-cygming: Add rules for winnt-cxx.o, winnt-stubs.o.

	PR target/19704
	* config/i386/i386.c (ix86_function_ok_for_sibcall): Replace test for
	dllimport attribute with test of DECL_DLLIMPORT_P.


cp
	PR target/21801
	PR target/23589
	* class.c (finish_struct_1): Call
	targetm.cxx.adjust_class_at_definition.


testsuite
	* gcc.dg/dll-2.c: Add tests for warnings.
	* gcc.dg/dll-3.c: Likewise.
	* gcc.dg/dll-4.c: Likewise.

	* g++.dg/ext/dllimport1.C: Adjust tests for warnings.
	* g++.dg/ext/dllimport2.C: Likewise.
	* g++.dg/ext/dllimport3.C: Likewise.
	* g++.dg/ext/dllimport7.C: Likewise.
	* g++.dg/ext/dllimport8.C: Likewise.
	* g++.dg/ext/dllimport9.C: Likewise.

From-SVN: r105332