openmp: Add support for allocator and align modifiers on allocate clauses

As the allocate-2.c testcase shows, this change isn't 100% backwards compatible,
one could have allocate and/or align functions that return an OpenMP allocator
handle and previously it would call those functions and now would use those
names as keywords for the modifiers.  But it allows specify extra alignment
requirements for the allocations.

2021-09-22  Jakub Jelinek  <jakub@redhat.com>

gcc/
	* tree.h (OMP_CLAUSE_ALLOCATE_ALIGN): Define.
	* tree.c (omp_clause_num_ops): Change number of OMP_CLAUSE_ALLOCATE
	arguments from 2 to 3.
	* tree-pretty-print.c (dump_omp_clause): Print allocator() around
	allocate clause allocator and print align if present.
	* omp-low.c (scan_sharing_clauses): Force allocate_map entry even
	for omp_default_mem_alloc if align modifier is present.  If align
	modifier is present, use TREE_LIST to encode both allocator and
	align.
	(lower_private_allocate, lower_rec_input_clauses, create_task_copyfn):
	Handle align modifier on allocator clause if present.
gcc/c-family/
	* c-omp.c (c_omp_split_clauses): Copy over OMP_CLAUSE_ALLOCATE_ALIGN.
gcc/c/
	* c-parser.c (c_parser_omp_clause_allocate): Parse allocate clause
	modifiers.
gcc/cp/
	* parser.c (cp_parser_omp_clause_allocate): Parse allocate clause
	modifiers.
	* semantics.c (finish_omp_clauses) <OMP_CLAUSE_ALLOCATE>: Perform
	semantic analysis of OMP_CLAUSE_ALLOCATE_ALIGN.
	* pt.c (tsubst_omp_clauses) <case OMP_CLAUSE_ALLOCATE>: Handle
	also OMP_CLAUSE_ALLOCATE_ALIGN.
gcc/testsuite/
	* c-c++-common/gomp/allocate-6.c: New test.
	* c-c++-common/gomp/allocate-7.c: New test.
	* g++.dg/gomp/allocate-4.C: New test.
libgomp/
	* testsuite/libgomp.c-c++-common/allocate-2.c: New test.
	* testsuite/libgomp.c-c++-common/allocate-3.c: New test.

1 files changed, 147 insertions, 14 deletions

diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index fb1399e..fa29d2c 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -15305,7 +15305,15 @@ c_parser_omp_clause_aligned (c_parser *parser, tree list)
 
 /* OpenMP 5.0:
    allocate ( variable-list )
-   allocate ( expression : variable-list ) */
+   allocate ( expression : variable-list )
+
+   OpenMP 5.1:
+   allocate ( allocator-modifier : variable-list )
+   allocate ( allocator-modifier , allocator-modifier : variable-list )
+
+   allocator-modifier:
+   allocator ( expression )
+   align ( expression )  */
 
 static tree
 c_parser_omp_clause_allocate (c_parser *parser, tree list)
@@ -15313,6 +15321,7 @@ c_parser_omp_clause_allocate (c_parser *parser, tree list)
   location_t clause_loc = c_parser_peek_token (parser)->location;
   tree nl, c;
   tree allocator = NULL_TREE;
+  tree align = NULL_TREE;
 
   matching_parens parens;
   if (!parens.require_open (parser))
@@ -15323,17 +15332,128 @@ c_parser_omp_clause_allocate (c_parser *parser, tree list)
       || (c_parser_peek_2nd_token (parser)->type != CPP_COMMA
 	  && c_parser_peek_2nd_token (parser)->type != CPP_CLOSE_PAREN))
     {
-      location_t expr_loc = c_parser_peek_token (parser)->location;
-      c_expr expr = c_parser_expr_no_commas (parser, NULL);
-      expr = convert_lvalue_to_rvalue (expr_loc, expr, false, true);
-      allocator = expr.value;
-      allocator = c_fully_fold (allocator, false, NULL);
-      tree orig_type
-	= expr.original_type ? expr.original_type : TREE_TYPE (allocator);
-      orig_type = TYPE_MAIN_VARIANT (orig_type);
-      if (!INTEGRAL_TYPE_P (TREE_TYPE (allocator))
-	  || TREE_CODE (orig_type) != ENUMERAL_TYPE
-	  || TYPE_NAME (orig_type) != get_identifier ("omp_allocator_handle_t"))
+      bool has_modifiers = false;
+      tree orig_type = NULL_TREE;
+      if (c_parser_next_token_is (parser, CPP_NAME)
+	  && c_parser_peek_2nd_token (parser)->type == CPP_OPEN_PAREN)
+	{
+	  unsigned int n = 3;
+	  const char *p
+	    = IDENTIFIER_POINTER (c_parser_peek_token (parser)->value);
+	  if ((strcmp (p, "allocator") == 0 || strcmp (p, "align") == 0)
+	      && c_parser_check_balanced_raw_token_sequence (parser, &n)
+	      && (c_parser_peek_nth_token_raw (parser, n)->type
+		  == CPP_CLOSE_PAREN))
+	    {
+	      if (c_parser_peek_nth_token_raw (parser, n + 1)->type
+		  == CPP_COLON)
+		has_modifiers = true;
+	      else if (c_parser_peek_nth_token_raw (parser, n + 1)->type
+		       == CPP_COMMA
+		       && (c_parser_peek_nth_token_raw (parser, n + 2)->type
+			   == CPP_NAME)
+		       && (c_parser_peek_nth_token_raw (parser, n + 3)->type
+			   == CPP_OPEN_PAREN))
+		{
+		  c_token *tok = c_parser_peek_nth_token_raw (parser, n + 2);
+		  const char *q = IDENTIFIER_POINTER (tok->value);
+		  n += 4;
+		  if ((strcmp (q, "allocator") == 0
+		       || strcmp (q, "align") == 0)
+		      && c_parser_check_balanced_raw_token_sequence (parser,
+								     &n)
+		      && (c_parser_peek_nth_token_raw (parser, n)->type
+			  == CPP_CLOSE_PAREN)
+		      && (c_parser_peek_nth_token_raw (parser, n + 1)->type
+			  == CPP_COLON))
+		    has_modifiers = true;
+		}
+	    }
+	  if (has_modifiers)
+	    {
+	      c_parser_consume_token (parser);
+	      matching_parens parens2;;
+	      parens2.require_open (parser);
+	      location_t expr_loc = c_parser_peek_token (parser)->location;
+	      c_expr expr = c_parser_expr_no_commas (parser, NULL);
+	      expr = convert_lvalue_to_rvalue (expr_loc, expr, false, true);
+	      if (strcmp (p, "allocator") == 0)
+		{
+		  allocator = expr.value;
+		  allocator = c_fully_fold (allocator, false, NULL);
+		  orig_type = expr.original_type
+			      ? expr.original_type : TREE_TYPE (allocator);
+		  orig_type = TYPE_MAIN_VARIANT (orig_type);
+		}
+	      else
+		{
+		  align = expr.value;
+		  align = c_fully_fold (align, false, NULL);
+		}
+	      parens2.skip_until_found_close (parser);
+	      if (c_parser_next_token_is (parser, CPP_COMMA))
+		{
+		  c_parser_consume_token (parser);
+		  c_token *tok = c_parser_peek_token (parser);
+		  const char *q = "";
+		  if (c_parser_next_token_is (parser, CPP_NAME))
+		    q = IDENTIFIER_POINTER (tok->value);
+		  if (strcmp (q, "allocator") != 0 && strcmp (q, "align") != 0)
+		    {
+		      c_parser_error (parser, "expected %<allocator%> or "
+					      "%<align%>");
+		      parens.skip_until_found_close (parser);
+		      return list;
+		    }
+		  else if (strcmp (p, q) == 0)
+		    {
+		      error_at (tok->location, "duplicate %qs modifier", p);
+		      parens.skip_until_found_close (parser);
+		      return list;
+		    }
+		  c_parser_consume_token (parser);
+		  if (!parens2.require_open (parser))
+		    {
+		      parens.skip_until_found_close (parser);
+		      return list;
+		    }
+		  expr_loc = c_parser_peek_token (parser)->location;
+		  expr = c_parser_expr_no_commas (parser, NULL);
+		  expr = convert_lvalue_to_rvalue (expr_loc, expr, false,
+						   true);
+		  if (strcmp (q, "allocator") == 0)
+		    {
+		      allocator = expr.value;
+		      allocator = c_fully_fold (allocator, false, NULL);
+		      orig_type = expr.original_type
+				  ? expr.original_type : TREE_TYPE (allocator);
+		      orig_type = TYPE_MAIN_VARIANT (orig_type);
+		    }
+		  else
+		    {
+		      align = expr.value;
+		      align = c_fully_fold (align, false, NULL);
+		    }
+		  parens2.skip_until_found_close (parser);
+		}
+	    }
+	}
+      if (!has_modifiers)
+	{
+	  location_t expr_loc = c_parser_peek_token (parser)->location;
+	  c_expr expr = c_parser_expr_no_commas (parser, NULL);
+	  expr = convert_lvalue_to_rvalue (expr_loc, expr, false, true);
+	  allocator = expr.value;
+	  allocator = c_fully_fold (allocator, false, NULL);
+	  orig_type = expr.original_type
+		      ? expr.original_type : TREE_TYPE (allocator);
+	  orig_type = TYPE_MAIN_VARIANT (orig_type);
+	}
+      if (allocator
+	  && (!INTEGRAL_TYPE_P (TREE_TYPE (allocator))
+	      || TREE_CODE (orig_type) != ENUMERAL_TYPE
+	      || (TYPE_NAME (orig_type)
+		  != get_identifier ("omp_allocator_handle_t"))))
         {
           error_at (clause_loc, "%<allocate%> clause allocator expression "
 				"has type %qT rather than "
@@ -15341,6 +15461,16 @@ c_parser_omp_clause_allocate (c_parser *parser, tree list)
 				TREE_TYPE (allocator));
           allocator = NULL_TREE;
         }
+      if (align
+	  && (!INTEGRAL_TYPE_P (TREE_TYPE (align))
+	      || !tree_fits_uhwi_p (align)
+	      || !integer_pow2p (align)))
+	{
+	  error_at (clause_loc, "%<allocate%> clause %<align%> modifier "
+				"argument needs to be positive constant "
+				"power of two integer expression");
+	  align = NULL_TREE;
+	}
       if (!c_parser_require (parser, CPP_COLON, "expected %<:%>"))
 	{
 	  parens.skip_until_found_close (parser);
@@ -15351,9 +15481,12 @@ c_parser_omp_clause_allocate (c_parser *parser, tree list)
   nl = c_parser_omp_variable_list (parser, clause_loc,
 				   OMP_CLAUSE_ALLOCATE, list);
 
-  if (allocator)
+  if (allocator || align)
     for (c = nl; c != list; c = OMP_CLAUSE_CHAIN (c))
-      OMP_CLAUSE_ALLOCATE_ALLOCATOR (c) = allocator;
+      {
+	OMP_CLAUSE_ALLOCATE_ALLOCATOR (c) = allocator;
+	OMP_CLAUSE_ALLOCATE_ALIGN (c) = align;
+      }
 
   parens.skip_until_found_close (parser);
   return nl;