This commit adds -fopenmp-allocators which enables support for
'omp allocators' and 'omp allocate' that are associated with a Fortran
allocate-stmt. If such a construct is encountered, an error is shown,
unless the -fopenmp-allocators flag is present.

With -fopenmp -fopenmp-allocators, those constructs get turned into
GOMP_alloc allocations, while -fopenmp-allocators (also without -fopenmp)
ensures deallocation and reallocation (via intrinsic assignments) are
properly directed to GOMP_free/omp_realloc - while normal Fortran
allocations are processed by free/realloc.

In order to distinguish a 'malloc'ed from a 'GOMP_alloc'ed memory, the
version field of the Fortran array discriptor is (mis)used: 0 indicates
the normal Fortran allocation while 1 denotes GOMP_alloc. For scalars,
there is record keeping in libgomp: GOMP_add_alloc(ptr) will add the
pointer address to a splay_tree while GOMP_is_alloc(ptr) will return
true it was previously added but also removes it from the list.

Besides Fortran FE work, BUILT_IN_GOMP_REALLOC is no part of
omp-builtins.def and libgomp gains the mentioned two new function.

gcc/ChangeLog:

	* builtin-types.def (BT_FN_PTR_PTR_SIZE_PTRMODE_PTRMODE): New.
	* omp-builtins.def (BUILT_IN_GOMP_REALLOC): New.
	* builtins.cc (builtin_fnspec): Handle it.
	* gimple-ssa-warn-access.cc (fndecl_alloc_p,
	matching_alloc_calls_p): Likewise.
	* gimple.cc (nonfreeing_call_p): Likewise.
	* predict.cc (expr_expected_value_1): Likewise.
	* tree-ssa-ccp.cc (evaluate_stmt): Likewise.
	* tree.cc (fndecl_dealloc_argno): Likewise.

gcc/fortran/ChangeLog:

	* dump-parse-tree.cc (show_omp_node): Handle EXEC_OMP_ALLOCATE
	and EXEC_OMP_ALLOCATORS.
	* f95-lang.cc (ATTR_ALLOC_WARN_UNUSED_RESULT_SIZE_2_NOTHROW_LIST):
	Add 'ECF_LEAF | ECF_MALLOC' to existing 'ECF_NOTHROW'.
	(ATTR_ALLOC_WARN_UNUSED_RESULT_SIZE_2_NOTHROW_LEAF_LIST): Define.
	* gfortran.h (gfc_omp_clauses): Add contained_in_target_construct.
	* invoke.texi (-fopenacc, -fopenmp): Update based on C version.
	(-fopenmp-simd): New, based on C version.
	(-fopenmp-allocators): New.
	* lang.opt (fopenmp-allocators): Add.
	* openmp.cc (resolve_omp_clauses): For allocators/allocate directive,
	add target and no dynamic_allocators diagnostic and more invalid
	diagnostic.
	* parse.cc (decode_omp_directive): Set contains_teams_construct.
	* trans-array.h (gfc_array_allocate): Update prototype.
	(gfc_conv_descriptor_version): New prototype.
	* trans-decl.cc (gfc_init_default_dt): Fix comment.
	* trans-array.cc (gfc_conv_descriptor_version): New.
	(gfc_array_allocate): Support GOMP_alloc allocation.
	(gfc_alloc_allocatable_for_assignment, structure_alloc_comps):
	Handle GOMP_free/omp_realloc as needed.
	* trans-expr.cc (gfc_conv_procedure_call): Likewise.
	(alloc_scalar_allocatable_for_assignment): Likewise.
	* trans-intrinsic.cc (conv_intrinsic_move_alloc): Likewise.
	* trans-openmp.cc (gfc_trans_omp_allocators,
	gfc_trans_omp_directive): Handle allocators/allocate directive.
	(gfc_omp_call_add_alloc, gfc_omp_call_is_alloc): New.
	* trans-stmt.h (gfc_trans_allocate): Update prototype.
	* trans-stmt.cc (gfc_trans_allocate): Support GOMP_alloc.
	* trans-types.cc (gfc_get_dtype_rank_type): Set version field.
	* trans.cc (gfc_allocate_using_malloc, gfc_allocate_allocatable):
	Update to handle GOMP_alloc.
	(gfc_deallocate_with_status, gfc_deallocate_scalar_with_status):
	Handle GOMP_free.
	(trans_code): Update call.
	* trans.h (gfc_allocate_allocatable, gfc_allocate_using_malloc):
	Update prototype.
	(gfc_omp_call_add_alloc, gfc_omp_call_is_alloc): New prototype.
	* types.def (BT_FN_PTR_PTR_SIZE_PTRMODE_PTRMODE): New.

libgomp/ChangeLog:

	* allocator.c (struct fort_alloc_splay_tree_key_s,
	fort_alloc_splay_compare, GOMP_add_alloc, GOMP_is_alloc): New.
	* libgomp.h: Define splay_tree_static for 'reverse' splay tree.
	* libgomp.map (GOMP_5.1.2): New; add GOMP_add_alloc and
	GOMP_is_alloc; move GOMP_target_map_indirect_ptr from ...
	(GOMP_5.1.1): ... here.
	* libgomp.texi (Impl. Status, Memory management): Update for
	allocators/allocate directives.
	* splay-tree.c: Handle splay_tree_static define to declare all
	functions as static.
	(splay_tree_lookup_node): New.
	* splay-tree.h: Handle splay_tree_decl_only define.
	(splay_tree_lookup_node): New prototype.
	* target.c: Define splay_tree_static for 'reverse'.
	* testsuite/libgomp.fortran/allocators-1.f90: New test.
	* testsuite/libgomp.fortran/allocators-2.f90: New test.
	* testsuite/libgomp.fortran/allocators-3.f90: New test.
	* testsuite/libgomp.fortran/allocators-4.f90: New test.
	* testsuite/libgomp.fortran/allocators-5.f90: New test.

gcc/testsuite/ChangeLog:

	* gfortran.dg/gomp/allocate-14.f90: Add coarray and
	not-listed tests.
	* gfortran.dg/gomp/allocate-5.f90: Remove sorry dg-message.
	* gfortran.dg/bind_c_array_params_2.f90: Update expected
	dump for dtype '.version=0'.
	* gfortran.dg/gomp/allocate-16.f90: New test.
	* gfortran.dg/gomp/allocators-3.f90: New test.
	* gfortran.dg/gomp/allocators-4.f90: New test.

This commit enabled reverse offload for nvptx such that gomp_target_rev
actually gets called.  And it fills the latter function to do all of
the following: finding the host function to the device func ptr and
copying the arguments to the host, processing the mapping/firstprivate,
calling the host function, copying back the data and freeing as needed.

The data handling is made easier by assuming that all host variables
either existed before (and are in the mapping) or that those are
devices variables not yet available on the host. Thus, the reverse
mapping can do without refcounts etc. Note that the spec disallows
inside a target region device-affecting constructs other than target
plus ancestor device-modifier and it also limits the clauses permitted
on this construct.

For the function addresses, an additional splay tree is used; for
the lookup of mapped variables, the existing splay-tree is used.
Unfortunately, its data structure requires a full walk of the tree;
Additionally, the just mapped variables are recorded in a separate
data structure an extra lookup. While the lookup is slow, assuming
that only few variables get mapped in each reverse offload construct
and that reverse offload is the exception and not performance critical,
this seems to be acceptable.

libgomp/ChangeLog:

	* libgomp.h (struct target_mem_desc): Predeclare; move
	below after 'reverse_splay_tree_node' and add rev_array
	member.
	(struct reverse_splay_tree_key_s, reverse_splay_compare): New.
	(reverse_splay_tree_node, reverse_splay_tree,
	reverse_splay_tree_key): New typedef.
	(struct gomp_device_descr): Add mem_map_rev member.
	* oacc-host.c (host_dispatch): NULL init .mem_map_rev.
	* plugin/plugin-nvptx.c (GOMP_OFFLOAD_get_num_devices): Claim
	support for GOMP_REQUIRES_REVERSE_OFFLOAD.
	* splay-tree.h (splay_tree_callback_stop): New typedef; like
	splay_tree_callback but returning int not void.
	(splay_tree_foreach_lazy): Define; like splay_tree_foreach but
	taking splay_tree_callback_stop as argument.
	* splay-tree.c (splay_tree_foreach_internal_lazy,
	splay_tree_foreach_lazy): New; but early exit if callback returns
	nonzero.
	* target.c: Instatiate splay_tree_c with splay_tree_prefix 'reverse'.
	(gomp_map_lookup_rev): New.
	(gomp_load_image_to_device): Handle reverse-offload function
	lookup table.
	(gomp_unload_image_from_device): Free devicep->mem_map_rev.
	(struct gomp_splay_tree_rev_lookup_data, gomp_splay_tree_rev_lookup,
	gomp_map_rev_lookup, struct cpy_data, gomp_map_cdata_lookup_int,
	gomp_map_cdata_lookup): New auxiliary structs and functions for
	gomp_target_rev.
	(gomp_target_rev): Implement reverse offloading and its mapping.
	(gomp_target_init): Init current_device.mem_map_rev.root.
	* testsuite/libgomp.fortran/reverse-offload-2.f90: New test.
	* testsuite/libgomp.fortran/reverse-offload-3.f90: New test.
	* testsuite/libgomp.fortran/reverse-offload-4.f90: New test.
	* testsuite/libgomp.fortran/reverse-offload-5.f90: New test.
	* testsuite/libgomp.fortran/reverse-offload-5a.f90: New test without
	mapping of on-device allocated variables.

From-SVN: r279813

From-SVN: r267494

From-SVN: r256169