OpenACC host_data support.

	gcc/
	* gimple-pretty-print.c (dump_gimple_omp_target): Add host_data
	support.
	* gimple.h (gf_mask): Add GF_OMP_TARGET_KIND_OACC_HOST_DATA.
	(is_gimple_omp_oacc): Add support for above.
	* gimplify.c (omp_region_type): Add ORT_ACC_HOST_DATA.
	(omp_notice_variable): Diagnose undefined implicit uses of
	use_device variables in offloaded regions.
	(gimplify_scan_omp_clauses): Add host_data, use_device
	support. Diagnose undefined mapping of use_device variables in
	OpenACC clauses.
	(gimplify_omp_workshare): Add host_data support.
	(gimplify_expr): Likewise.
	* omp-builtins.def (BUILT_IN_GOACC_HOST_DATA): New.
	* omp-low.c (lookup_decl_in_outer_ctx)
	(maybe_lookup_decl_in_outer_ctx): Add optional argument to skip
	host_data regions.
	(scan_sharing_clauses): Support use_device.
	(check_omp_nesting_restrictions): Support host_data.
	(expand_omp_target): Support host_data.
	(lower_omp_target): Skip over outer host_data regions when looking
	up decls. Support use_device.
	(make_gimple_omp_edges): Support host_data.
	* tree-nested.c (convert_nonlocal_omp_clauses): Add use_device
	clause.

	gcc/c/
	* c-parser.c (c_parser_omp_clause_name): Add use_device support.
	(c_parser_oacc_clause_use_device): New function.
	(c_parser_oacc_all_clauses): Add use_device support.
	(OACC_HOST_DATA_CLAUSE_MASK): New macro.
	(c_parser_oacc_host_data): New function.
	(c_parser_omp_construct): Add host_data support.
	* c-tree.h (c_finish_oacc_host_data): Add prototype.
	* c-typeck.c (c_finish_oacc_host_data): New function.
	(c_finish_omp_clauses): Add use_device support.

	gcc/cp/
	* cp-tree.h (finish_oacc_host_data): Add prototype.
	* parser.c (cp_parser_omp_clause_name): Add use_device support.
	(cp_parser_oacc_all_clauses): Add use_device support.
	(OACC_HOST_DATA_CLAUSE_MASK): New macro.
	(cp_parser_oacc_host_data): New function.
	(cp_parser_omp_construct): Add host_data support.
	(cp_parser_pragma): Add host_data support.
	* semantics.c (finish_omp_clauses): Add use_device support.
	(finish_oacc_host_data): New function.

	gcc/c-family/
	* c-pragma.c (oacc_pragmas): Add PRAGMA_OACC_HOST_DATA.
	* c-pragma.h (pragma_kind): Add PRAGMA_OACC_HOST_DATA.
	(pragma_omp_clause): Add PRAGMA_OACC_CLAUSE_USE_DEVICE.

	libgomp/
	* oacc-parallel.c (GOACC_host_data): New function.
	* libgomp.map (GOACC_host_data): Add to GOACC_2.0.1.
	* testsuite/libgomp.oacc-c-c++-common/host_data-1.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/host_data-2.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/host_data-3.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/host_data-4.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/host_data-5.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/host_data-6.c: New test.


Co-Authored-By: Cesar Philippidis <cesar@codesourcery.com>
Co-Authored-By: James Norris <James_Norris@mentor.com>

From-SVN: r231118