openmp: Diagnose some superfluous commas in OpenMP parsing

While working on error directive, I've noticed a few spots in OpenMP
parsing where we consume and don't diagnose superfluous commas at the end
(either of depend sink arguments or at the end of requires pragma).

2021-08-20  Jakub Jelinek  <jakub@redhat.com>

gcc/c/
	* c-parser.c (c_parser_omp_clause_depend_sink): Reject spurious
	comma at the end of list.
	(c_parser_omp_requires): Likewise.
gcc/cp/
	* parser.c (cp_parser_omp_clause_depend_sink): Reject spurious
	comma at the end of list.  Don't parse closing paren here...
	(cp_parser_omp_clause_depend): ... but here instead.
gcc/testsuite/
	* c-c++-common/gomp/sink-5.c: New test.
	* c-c++-common/gomp/requires-3.c: Add test for spurious comma
	at the end of pragma line.

gcc/c/c-parser.c

@@ -15481,7 +15481,9 @@ c_parser_omp_clause_depend_sink (c_parser *parser, location_t clause_loc,
 	    OMP_CLAUSE_DEPEND_SINK_NEGATIVE (vec) = 1;
 	}
 
-      if (c_parser_next_token_is_not (parser, CPP_COMMA))
+      if (c_parser_next_token_is_not (parser, CPP_COMMA)
+	  || c_parser_peek_2nd_token (parser)->type != CPP_NAME
+	  || c_parser_peek_2nd_token (parser)->id_kind != C_ID_ID)
 	break;
 
       c_parser_consume_token (parser);
@@ -21663,7 +21665,9 @@ c_parser_omp_requires (c_parser *parser)
   location_t loc = c_parser_peek_token (parser)->location;
   while (c_parser_next_token_is_not (parser, CPP_PRAGMA_EOL))
     {
-      if (!first && c_parser_next_token_is (parser, CPP_COMMA))
+      if (!first
+	  && c_parser_next_token_is (parser, CPP_COMMA)
+	  && c_parser_peek_2nd_token (parser)->type == CPP_NAME)
 	c_parser_consume_token (parser);
 
       first = false;

gcc/cp/parser.c

@@ -38465,13 +38465,14 @@ cp_parser_omp_clause_depend_sink (cp_parser *parser, location_t clause_loc,
 	    OMP_CLAUSE_DEPEND_SINK_NEGATIVE (vec) = 1;
 	}
 
-      if (cp_lexer_next_token_is_not (parser->lexer, CPP_COMMA))
+      if (cp_lexer_next_token_is_not (parser->lexer, CPP_COMMA)
+	  || !cp_lexer_nth_token_is (parser->lexer, 2, CPP_NAME))
 	break;
 
       cp_lexer_consume_token (parser->lexer);
     }
 
-  if (cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN) && vec)
+  if (vec)
     {
       tree u = build_omp_clause (clause_loc, OMP_CLAUSE_DEPEND);
       OMP_CLAUSE_DEPEND_KIND (u) = OMP_CLAUSE_DEPEND_SINK;
@@ -38791,7 +38792,13 @@ cp_parser_omp_clause_depend (cp_parser *parser, tree list, location_t loc)
     goto resync_fail;
 
   if (kind == OMP_CLAUSE_DEPEND_SINK)
-    nlist = cp_parser_omp_clause_depend_sink (parser, loc, list);
+    {
+      nlist = cp_parser_omp_clause_depend_sink (parser, loc, list);
+      if (!parens.require_close (parser))
+	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
+					       /*or_comma=*/false,
+					       /*consume_paren=*/true);
+    }
   else
     {
       nlist = cp_parser_omp_var_list_no_open (parser, OMP_CLAUSE_DEPEND,

gcc/testsuite/c-c++-common/gomp/requires-3.c

@@ -3,3 +3,4 @@
 #pragma omp requires atomic_default_mem_order(foobar)	/* { dg-error "expected 'seq_cst', 'relaxed' or 'acq_rel'" } */
 #pragma omp requires atomic_default_mem_order (	/* { dg-error "expected 'seq_cst', 'relaxed' or 'acq_rel'" } */
 /* { dg-error "expected '\\\)' before end of line" "" { target *-*-* } .-1 } */
+#pragma omp requires atomic_default_mem_order(seq_cst),	/* { dg-error "expected end of line before ',' token" } */

gcc/testsuite/c-c++-common/gomp/sink-5.c

@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+
+void bar (int);
+
+void
+foo ()
+{
+  int i;
+#pragma omp parallel for ordered(1)
+  for (i = 0; i < 100; ++i)
+    {
+#pragma omp ordered depend(sink:i-1,)	/* { dg-error "expected '\\\)' before ',' token" } */
+      bar (i);
+#pragma omp ordered depend(source)
+    }
+}