openmp: Add support for the 'present' modifier

This implements support for the OpenMP 5.1 'present' modifier, which can be
used in map clauses in the 'target', 'target data', 'target data enter' and
'target data exit' constructs, and in the 'to' and 'from' clauses of the
'target update' construct.  It is also supported in defaultmap.

The modifier triggers a fatal runtime error if the data specified by the
clause is not already present on the target device.  It can also be combined
with 'always' in map clauses.

2023-06-06  Kwok Cheung Yeung  <kcy@codesourcery.com>
	    Tobias Burnus  <tobias@codesourcery.com>

gcc/c/
	* c-parser.cc (c_parser_omp_clause_defaultmap,
	c_parser_omp_clause_map): Parse 'present'.
	(c_parser_omp_clause_to, c_parser_omp_clause_from): Remove.
	(c_parser_omp_clause_from_to): New; parse to/from clauses with
	optional present modifer.
	(c_parser_omp_all_clauses): Update call.
	(c_parser_omp_target_data, c_parser_omp_target_enter_data,
	c_parser_omp_target_exit_data): Handle new map enum values
	for 'present' mapping.

gcc/cp/
	* parser.cc (cp_parser_omp_clause_defaultmap,
	cp_parser_omp_clause_map): Parse 'present'.
	(cp_parser_omp_clause_from_to): New; parse to/from
	clauses with optional 'present' modifier.
	(cp_parser_omp_all_clauses): Update call.
	(cp_parser_omp_target_data, cp_parser_omp_target_enter_data,
	cp_parser_omp_target_exit_data): Handle new enum value for
	'present' mapping.
	* semantics.cc (finish_omp_target): Likewise.

gcc/fortran/
	* dump-parse-tree.cc (show_omp_namelist): Display 'present' map
	modifier.
	(show_omp_clauses): Display 'present' motion modifier for 'to'
	and 'from' clauses.

	* gfortran.h (enum gfc_omp_map_op): Add entries with 'present'
	modifiers.
	(struct gfc_omp_namelist): Add 'present_modifer'.
	* openmp.cc (gfc_match_motion_var_list): New, handles optional
	'present' modifier for to/from clauses.
	(gfc_match_omp_clauses): Call it for to/from clauses; parse 'present'
	in defaultmap and map clauses.
	(resolve_omp_clauses): Allow 'present' modifiers on 'target',
	'target data', 'target enter' and 'target exit'	directives.
	* trans-openmp.cc (gfc_trans_omp_clauses): Apply 'present' modifiers
	to tree node for 'map', 'to' and 'from'	clauses.  Apply 'present' for
	defaultmap.

gcc/
	* gimplify.cc (omp_notice_variable): Apply GOVD_MAP_ALLOC_ONLY flag
	and defaultmap flags if the defaultmap has GOVD_MAP_FORCE_PRESENT flag
	set.
	(omp_get_attachment): Handle map clauses with 'present' modifier.
	(omp_group_base): Likewise.
	(gimplify_scan_omp_clauses): Reorder present maps to come first.
	Set GOVD flags for present defaultmaps.
	(gimplify_adjust_omp_clauses_1): Set map kind for present defaultmaps.
	* omp-low.cc (scan_sharing_clauses): Handle 'always, present' map
	clauses.
	(lower_omp_target): Handle map clauses with 'present' modifier.
	Handle 'to' and 'from' clauses with 'present'.
	* tree-core.h (enum omp_clause_defaultmap_kind): Add
	OMP_CLAUSE_DEFAULTMAP_PRESENT defaultmap kind.
	* tree-pretty-print.cc (dump_omp_clause): Handle 'map', 'to' and
	'from' clauses with 'present' modifier.  Handle present defaultmap.
	* tree.h (OMP_CLAUSE_MOTION_PRESENT): New #define.

include/
	* gomp-constants.h (GOMP_MAP_FLAG_SPECIAL_5): New.
	(GOMP_MAP_FLAG_FORCE): Redefine.
	(GOMP_MAP_FLAG_PRESENT, GOMP_MAP_FLAG_ALWAYS_PRESENT): New.
	(enum gomp_map_kind): Add map kinds with 'present' modifiers.
	(GOMP_MAP_COPY_TO_P, GOMP_MAP_COPY_FROM_P): Evaluate to true for
	map variants with 'present'
	(GOMP_MAP_ALWAYS_TO_P, GOMP_MAP_ALWAYS_FROM_P): Evaluate to true
	for map variants with 'always, present' modifiers.
	(GOMP_MAP_ALWAYS): Redefine.
	(GOMP_MAP_FORCE_P, GOMP_MAP_PRESENT_P): New.

libgomp/
	* libgomp.texi (OpenMP 5.1 Impl. status): Set 'present' support for
	defaultmap to 'Y', add 'Y' entry for 'present' on to/from/map clauses.
	* target.c (gomp_to_device_kind_p): Add map kinds with 'present'
	modifier.
	(gomp_map_vars_existing): Use new GOMP_MAP_FORCE_P macro.
	(gomp_map_vars_internal, gomp_update, gomp_target_rev):
	Emit runtime error if memory region not present.
	* testsuite/libgomp.c-c++-common/target-present-1.c: New test.
	* testsuite/libgomp.c-c++-common/target-present-2.c: New test.
	* testsuite/libgomp.c-c++-common/target-present-3.c: New test.
	* testsuite/libgomp.fortran/target-present-1.f90: New test.
	* testsuite/libgomp.fortran/target-present-2.f90: New test.
	* testsuite/libgomp.fortran/target-present-3.f90: New test.

gcc/testsuite/

	* c-c++-common/gomp/map-6.c: Update dg-error, extend to test for
	duplicated 'present' and extend scan-dump tests for 'present'.
	* gfortran.dg/gomp/defaultmap-1.f90: Update dg-error.
	* gfortran.dg/gomp/map-7.f90: Extend parse and dump test for
	'present'.
	* gfortran.dg/gomp/map-8.f90: Extend for duplicate 'present'
	modifier checking.
	* c-c++-common/gomp/defaultmap-4.c: New test.
	* c-c++-common/gomp/map-9.c: New test.
	* c-c++-common/gomp/target-update-1.c: New test.
	* gfortran.dg/gomp/defaultmap-8.f90: New test.
	* gfortran.dg/gomp/map-11.f90: New test.
	* gfortran.dg/gomp/map-12.f90: New test.
	* gfortran.dg/gomp/target-update-1.f90: New test.

1 files changed, 40 insertions, 7 deletions

diff --git a/include/gomp-constants.h b/include/gomp-constants.h
index 1b9b07dc245..49b7dd86ff5 100644
--- a/include/gomp-constants.h
+++ b/include/gomp-constants.h
@@ -42,6 +42,7 @@
 #define GOMP_MAP_FLAG_SPECIAL_2		(1 << 4)
 #define GOMP_MAP_FLAG_SPECIAL_3		(1 << 5)
 #define GOMP_MAP_FLAG_SPECIAL_4		(1 << 6)
+#define GOMP_MAP_FLAG_SPECIAL_5		(1 << 7)
 #define GOMP_MAP_FLAG_SPECIAL		(GOMP_MAP_FLAG_SPECIAL_1 \
 					 | GOMP_MAP_FLAG_SPECIAL_0)
 #define GOMP_MAP_DEEP_COPY		(GOMP_MAP_FLAG_SPECIAL_4 \
@@ -55,9 +56,14 @@
 					 | GOMP_MAP_FLAG_SPECIAL_1 \
 					 | GOMP_MAP_FLAG_SPECIAL_2 \
 					 | GOMP_MAP_FLAG_SPECIAL_3 \
-					 | GOMP_MAP_FLAG_SPECIAL_4)
+					 | GOMP_MAP_FLAG_SPECIAL_4 \
+					 | GOMP_MAP_FLAG_SPECIAL_5)
 /* Flag to force a specific behavior (or else, trigger a run-time error).  */
-#define GOMP_MAP_FLAG_FORCE		(1 << 7)
+#define GOMP_MAP_FLAG_FORCE		(GOMP_MAP_FLAG_SPECIAL_5)
+#define GOMP_MAP_FLAG_PRESENT		(GOMP_MAP_FLAG_SPECIAL_5 \
+					 | GOMP_MAP_FLAG_SPECIAL_0)
+#define GOMP_MAP_FLAG_ALWAYS_PRESENT	(GOMP_MAP_FLAG_SPECIAL_2 \
+					 | GOMP_MAP_FLAG_PRESENT)
 
 enum gomp_map_kind
   {
@@ -130,6 +136,23 @@ enum gomp_map_kind
        device.  */
     GOMP_MAP_ALWAYS_TOFROM =		(GOMP_MAP_FLAG_SPECIAL_2
 					 | GOMP_MAP_TOFROM),
+    /* Must already be present.  */
+    GOMP_MAP_PRESENT_ALLOC =		(GOMP_MAP_FLAG_PRESENT | GOMP_MAP_ALLOC),
+    /* Must already be present, copy to device.  */
+    GOMP_MAP_PRESENT_TO =		(GOMP_MAP_FLAG_PRESENT | GOMP_MAP_TO),
+    /* Must already be present, copy from device.  */
+    GOMP_MAP_PRESENT_FROM =		(GOMP_MAP_FLAG_PRESENT | GOMP_MAP_FROM),
+    /* Must already be present, copy to and from device.  */
+    GOMP_MAP_PRESENT_TOFROM =		(GOMP_MAP_FLAG_PRESENT | GOMP_MAP_TOFROM),
+    /* Must already be present, unconditionally copy to device.  */
+    GOMP_MAP_ALWAYS_PRESENT_TO =	(GOMP_MAP_FLAG_ALWAYS_PRESENT
+					 | GOMP_MAP_TO),
+    /* Must already be present, unconditionally copy from device.  */
+    GOMP_MAP_ALWAYS_PRESENT_FROM =	(GOMP_MAP_FLAG_ALWAYS_PRESENT
+					 | GOMP_MAP_FROM),
+    /* Must already be present, unconditionally copy to and from device.  */
+    GOMP_MAP_ALWAYS_PRESENT_TOFROM =	(GOMP_MAP_FLAG_ALWAYS_PRESENT
+					 | GOMP_MAP_TOFROM),
     /* Map a sparse struct; the address is the base of the structure, alignment
        it's required alignment, and size is the number of adjacent entries
        that belong to the struct.  The adjacent entries should be sorted by
@@ -186,11 +209,11 @@ enum gomp_map_kind
   };
 
 #define GOMP_MAP_COPY_TO_P(X) \
-  (!((X) & GOMP_MAP_FLAG_SPECIAL) \
+  ((!((X) & GOMP_MAP_FLAG_SPECIAL) || GOMP_MAP_PRESENT_P (X)) \
    && ((X) & GOMP_MAP_FLAG_TO))
 
 #define GOMP_MAP_COPY_FROM_P(X) \
-  (!((X) & GOMP_MAP_FLAG_SPECIAL) \
+  ((!((X) & GOMP_MAP_FLAG_SPECIAL) || GOMP_MAP_PRESENT_P (X)) \
    && ((X) & GOMP_MAP_FLAG_FROM))
 
 #define GOMP_MAP_ALWAYS_POINTER_P(X) \
@@ -201,17 +224,27 @@ enum gomp_map_kind
    || (X) == GOMP_MAP_POINTER_TO_ZERO_LENGTH_ARRAY_SECTION)
 
 #define GOMP_MAP_ALWAYS_TO_P(X) \
-  (((X) == GOMP_MAP_ALWAYS_TO) || ((X) == GOMP_MAP_ALWAYS_TOFROM))
+  (((X) == GOMP_MAP_ALWAYS_TO) || ((X) == GOMP_MAP_ALWAYS_TOFROM) \
+   || ((X) == GOMP_MAP_ALWAYS_PRESENT_TO) \
+   || ((X) == GOMP_MAP_ALWAYS_PRESENT_TOFROM))
 
 #define GOMP_MAP_ALWAYS_FROM_P(X) \
-  (((X) == GOMP_MAP_ALWAYS_FROM) || ((X) == GOMP_MAP_ALWAYS_TOFROM))
+  (((X) == GOMP_MAP_ALWAYS_FROM) || ((X) == GOMP_MAP_ALWAYS_TOFROM) \
+   || ((X) == GOMP_MAP_ALWAYS_PRESENT_FROM) \
+   || ((X) == GOMP_MAP_ALWAYS_PRESENT_TOFROM))
 
 #define GOMP_MAP_ALWAYS_P(X) \
-  (GOMP_MAP_ALWAYS_TO_P (X) || ((X) == GOMP_MAP_ALWAYS_FROM))
+  (GOMP_MAP_ALWAYS_TO_P (X) || GOMP_MAP_ALWAYS_FROM_P (X))
 
 #define GOMP_MAP_IMPLICIT_P(X) \
   (((X) & GOMP_MAP_FLAG_SPECIAL_BITS) == GOMP_MAP_IMPLICIT)
 
+#define GOMP_MAP_FORCE_P(X) \
+  (((X) & GOMP_MAP_FLAG_SPECIAL_BITS) == GOMP_MAP_FLAG_FORCE)
+
+#define GOMP_MAP_PRESENT_P(X) \
+  (((X) & GOMP_MAP_FLAG_PRESENT) == GOMP_MAP_FLAG_PRESENT)
+
 
 /* Asynchronous behavior.  Keep in sync with
    libgomp/{openacc.h,openacc.f90,openacc_lib.h}:acc_async_t.  */