openmp: Add support for iterators in map clauses (C/C++)

This adds preliminary support for iterators in map clauses within OpenMP
'target' constructs (which includes constructs such as 'target enter data').

Iterators with non-constant loop bounds are not currently supported.

gcc/c/

	* c-parser.cc (c_parser_omp_clause_map): Parse 'iterator' modifier.
	* c-typeck.cc (c_finish_omp_clauses): Finish iterators.  Apply
	iterators to generated clauses.

gcc/cp/

	* parser.cc (cp_parser_omp_clause_map): Parse 'iterator' modifier.
	* semantics.cc (finish_omp_clauses): Finish iterators.  Apply
	iterators to generated clauses.

gcc/

	* gimple-pretty-print.cc (dump_gimple_omp_target): Print expanded
	iterator loops.
	* gimple.cc (gimple_build_omp_target): Add argument for iterator
	loops sequence.  Initialize iterator loops field.
	* gimple.def (GIMPLE_OMP_TARGET): Set GSS symbol to GSS_OMP_TARGET.
	* gimple.h (gomp_target): Set GSS symbol to GSS_OMP_TARGET.  Add extra
	field for iterator loops.
	(gimple_build_omp_target): Add argument for iterator loops sequence.
	(gimple_omp_target_iterator_loops): New.
	(gimple_omp_target_iterator_loops_ptr): New.
	(gimple_omp_target_set_iterator_loops): New.
	* gimplify.cc (find_var_decl): New.
	(copy_omp_iterator): New.
	(remap_omp_iterator_var_1): New.
	(remap_omp_iterator_var): New.
	(remove_unused_omp_iterator_vars): New.
	(struct iterator_loop_info_t): New type.
	(iterator_loop_info_map_t): New type.
	(build_omp_iterators_loops): New.
	(enter_omp_iterator_loop_context_1): New.
	(enter_omp_iterator_loop_context): New.
	(enter_omp_iterator_loop_context): New.
	(exit_omp_iterator_loop_context): New.
	(gimplify_adjust_omp_clauses): Add argument for iterator loop
	sequence.  Gimplify the clause decl and size into the iterator
	loop if iterators are used.
	(gimplify_omp_workshare): Call remove_unused_omp_iterator_vars and
	build_omp_iterators_loops for OpenMP target expressions.  Add
	loop sequence as argument when calling gimplify_adjust_omp_clauses
	and building the Gimple statement.
	* gimplify.h (enter_omp_iterator_loop_context): New prototype.
	(exit_omp_iterator_loop_context): New prototype.
	* gsstruct.def (GSS_OMP_TARGET): New.
	* omp-low.cc (lower_omp_map_iterator_expr): New.
	(lower_omp_map_iterator_size): New.
	(finish_omp_map_iterators): New.
	(lower_omp_target): Add sorry if iterators used with deep mapping.
	Call lower_omp_map_iterator_expr before assigning to sender ref.
	Call lower_omp_map_iterator_size before setting the size.  Insert
	iterator loop sequence before the statements for the target clause.
	* tree-nested.cc (convert_nonlocal_reference_stmt): Walk the iterator
	loop sequence of OpenMP target statements.
	(convert_local_reference_stmt): Likewise.
	(convert_tramp_reference_stmt): Likewise.
	* tree-pretty-print.cc (dump_omp_iterators): Dump extra iterator
	information if present.
	(dump_omp_clause): Call dump_omp_iterators for iterators in map
	clauses.
	* tree.cc (omp_clause_num_ops): Add operand for OMP_CLAUSE_MAP.
	(walk_tree_1): Do not walk last operand of OMP_CLAUSE_MAP.
	* tree.h (OMP_CLAUSE_HAS_ITERATORS): New.
	(OMP_CLAUSE_ITERATORS): New.

gcc/testsuite/

	* c-c++-common/gomp/map-6.c (foo): Amend expected error message.
	* c-c++-common/gomp/target-map-iterators-1.c: New.
	* c-c++-common/gomp/target-map-iterators-2.c: New.
	* c-c++-common/gomp/target-map-iterators-3.c: New.
	* c-c++-common/gomp/target-map-iterators-4.c: New.

libgomp/

	* target.c (kind_to_name): New.
	(gomp_merge_iterator_maps): New.
	(gomp_map_vars_internal): Call gomp_merge_iterator_maps.  Copy
	address of only the first iteration to target vars.  Free allocated
	variables.
	* testsuite/libgomp.c-c++-common/target-map-iterators-1.c: New.
	* testsuite/libgomp.c-c++-common/target-map-iterators-2.c: New.
	* testsuite/libgomp.c-c++-common/target-map-iterators-3.c: New.

Co-authored-by: Andrew Stubbs <ams@baylibre.com>

1 files changed, 50 insertions, 6 deletions

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index fbaa917..8c85cce 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -20487,7 +20487,7 @@ c_parser_omp_clause_doacross (c_parser *parser, tree list)
    map ( [map-type-modifier[,] ...] map-kind: variable-list )
 
    map-type-modifier:
-     always | close */
+     always | close | present | iterator (iterators-definition)  */
 
 static tree
 c_parser_omp_clause_map (c_parser *parser, tree list, enum gomp_map_kind kind)
@@ -20501,15 +20501,35 @@ c_parser_omp_clause_map (c_parser *parser, tree list, enum gomp_map_kind kind)
 
   int pos = 1;
   int map_kind_pos = 0;
-  while (c_parser_peek_nth_token_raw (parser, pos)->type == CPP_NAME)
+  int iterator_length = 0;
+  for (;;)
     {
-      if (c_parser_peek_nth_token_raw (parser, pos + 1)->type == CPP_COLON)
+      c_token *tok = c_parser_peek_nth_token_raw (parser, pos);
+      if (tok->type != CPP_NAME)
+	break;
+
+      const char *p = IDENTIFIER_POINTER (tok->value);
+      c_token *next_tok = c_parser_peek_nth_token_raw (parser, pos + 1);
+      if (strcmp (p, "iterator") == 0 && next_tok->type == CPP_OPEN_PAREN)
+	{
+	  unsigned n = pos + 2;
+	  if (c_parser_check_balanced_raw_token_sequence (parser, &n)
+	      && c_parser_peek_nth_token_raw (parser, n)->type
+		 == CPP_CLOSE_PAREN)
+	    {
+	      iterator_length = n - pos + 1;
+	      pos = n;
+	      next_tok = c_parser_peek_nth_token_raw (parser, pos + 1);
+	    }
+	}
+
+      if (next_tok->type == CPP_COLON)
 	{
 	  map_kind_pos = pos;
 	  break;
 	}
 
-      if (c_parser_peek_nth_token_raw (parser, pos + 1)->type == CPP_COMMA)
+      if (next_tok->type == CPP_COMMA)
 	pos++;
       else if (c_parser_peek_nth_token_raw (parser, pos + 1)->type
 	       == CPP_OPEN_PAREN)
@@ -20531,6 +20551,7 @@ c_parser_omp_clause_map (c_parser *parser, tree list, enum gomp_map_kind kind)
   int present_modifier = 0;
   int mapper_modifier = 0;
   tree mapper_name = NULL_TREE;
+  tree iterators = NULL_TREE;
   for (int pos = 1; pos < map_kind_pos; ++pos)
     {
       c_token *tok = c_parser_peek_token (parser);
@@ -20628,11 +20649,24 @@ c_parser_omp_clause_map (c_parser *parser, tree list, enum gomp_map_kind kind)
 	  present_modifier++;
 	  c_parser_consume_token (parser);
 	}
+      else if (strcmp ("iterator", p) == 0
+	       && c_parser_peek_2nd_token (parser)->type == CPP_OPEN_PAREN)
+	{
+	  if (iterators)
+	    {
+	      c_parser_error (parser, "too many %<iterator%> modifiers");
+	      parens.skip_until_found_close (parser);
+	      return list;
+	    }
+	  iterators = c_parser_omp_iterators (parser);
+	  pos += iterator_length - 1;
+	  continue;
+	}
       else
 	{
 	  c_parser_error (parser, "%<map%> clause with map-type modifier other "
-				  "than %<always%>, %<close%>, %<mapper%> or "
-				  "%<present%>");
+				  "than %<always%>, %<close%>, %<iterator%>, "
+				  "%<mapper%> or %<present%>");
 	  parens.skip_until_found_close (parser);
 	  return list;
 	}
@@ -20683,9 +20717,19 @@ c_parser_omp_clause_map (c_parser *parser, tree list, enum gomp_map_kind kind)
 
   tree last_new = NULL_TREE;
 
+  if (iterators)
+    {
+      tree block = pop_scope ();
+      if (iterators == error_mark_node)
+	iterators = NULL_TREE;
+      else
+	TREE_VEC_ELT (iterators, 5) = block;
+    }
+
   for (c = nl; c != list; c = OMP_CLAUSE_CHAIN (c))
     {
       OMP_CLAUSE_SET_MAP_KIND (c, kind);
+      OMP_CLAUSE_ITERATORS (c) = iterators;
       last_new = c;
     }