openmp: Diagnose another case of mixing parameter and attribute syntax

This patch diagnoses cases like:
  #pragma omp parallel
  [[omp::directive (declare simd)]] int foo ();
or
  #pragma omp taskgroup
  int bar [[omp::directive (declare simd)]] (int);
where the pragma is on the same declaration statement as the declare simd
attribute.

2021-08-12  Jakub Jelinek  <jakub@redhat.com>

	* parser.c (cp_parser_lambda_body): Add temp overrides
	for parser->{omp_declare_simd,oacc_routine,omp_attrs_forbidden_p}.
	(cp_parser_statement): Restore parser->omp_attrs_forbidden_p for
	cp_parser_declaration_statement.
	(cp_parser_default_argument): Add temp override for
	parser->omp_attrs_forbidden_p.
	(cp_parser_late_parsing_omp_declare_simd): Diagnose declare simd
	or declare variant in attribute syntax on a declaration immediately
	following an OpenMP construct in pragma syntax.

	* g++.dg/gomp/attrs-11.C: Add new tests.

2 files changed, 27 insertions, 0 deletions

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index ec885d7..fbb8130 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -11628,6 +11628,9 @@ cp_parser_lambda_body (cp_parser* parser, tree lambda_expr)
        middle of an expression.  */
     ++function_depth;
 
+  auto odsd = make_temp_override (parser->omp_declare_simd, NULL);
+  auto ord = make_temp_override (parser->oacc_routine, NULL);
+  auto oafp = make_temp_override (parser->omp_attrs_forbidden_p, false);
   vec<tree> omp_privatization_save;
   save_omp_privatization_clauses (omp_privatization_save);
   /* Clear this in case we're in the middle of a default argument.  */
@@ -12271,9 +12274,11 @@ cp_parser_statement (cp_parser* parser, tree in_statement_expr,
 	       so let's un-parse them.  */
 	    saved_tokens.rollback();
 
+	  parser->omp_attrs_forbidden_p = omp_attrs_forbidden_p;
 	  cp_parser_parse_tentatively (parser);
 	  /* Try to parse the declaration-statement.  */
 	  cp_parser_declaration_statement (parser);
+	  parser->omp_attrs_forbidden_p = false;
 	  /* If that worked, we're done.  */
 	  if (cp_parser_parse_definitely (parser))
 	    return;
@@ -24768,6 +24773,8 @@ cp_parser_default_argument (cp_parser *parser, bool template_parm_p)
   parser->greater_than_is_operator_p = !template_parm_p;
   auto odsd = make_temp_override (parser->omp_declare_simd, NULL);
   auto ord = make_temp_override (parser->oacc_routine, NULL);
+  auto oafp = make_temp_override (parser->omp_attrs_forbidden_p, false);
+
   /* Local variable names (and the `this' keyword) may not
      appear in a default argument.  */
   saved_local_variables_forbidden_p = parser->local_variables_forbidden_p;
@@ -44503,6 +44510,14 @@ cp_parser_late_parsing_omp_declare_simd (cp_parser *parser, tree attrs)
 		    continue;
 		  }
 
+		if (parser->omp_attrs_forbidden_p)
+		  {
+		    error_at (first->location,
+			      "mixing OpenMP directives with attribute and "
+			      "pragma syntax on the same statement");
+		    parser->omp_attrs_forbidden_p = false;
+		  }
+
 		if (!flag_openmp && strcmp (directive[1], "simd") != 0)
 		  continue;
 		if (lexer == NULL)
diff --git a/gcc/testsuite/g++.dg/gomp/attrs-11.C b/gcc/testsuite/g++.dg/gomp/attrs-11.C
index 009bcb2..44e025e 100644
--- a/gcc/testsuite/g++.dg/gomp/attrs-11.C
+++ b/gcc/testsuite/g++.dg/gomp/attrs-11.C
@@ -72,3 +72,15 @@ int f28 [[omp::directive (declare simd), omp::directive (foobar)]] (int);	// { d
 int f29 [[omp::directive (foobar), omp::directive (declare simd)]] (int);	// { dg-error "unknown OpenMP directive name" }
 int f30 [[omp::directive (threadprivate (t7)), omp::directive (declare simd)]] (int);	// { dg-error "OpenMP directive other than 'declare simd' or 'declare variant' appertains to a declaration" }
 int f31 [[omp::directive (declare simd), omp::directive (threadprivate (t8))]] (int);	// { dg-error "OpenMP directive other than 'declare simd' or 'declare variant' appertains to a declaration" }
+
+void
+baz ()
+{
+  #pragma omp parallel
+  [[omp::directive (declare simd)]] extern int f32 (int);	// { dg-error "mixing OpenMP directives with attribute and pragma syntax on the same statement" }
+  #pragma omp parallel
+  extern int f33 [[omp::directive (declare simd)]] (int);	// { dg-error "mixing OpenMP directives with attribute and pragma syntax on the same statement" }
+  [[omp::directive (parallel)]]
+  #pragma omp declare simd	// { dg-error "mixing OpenMP directives with attribute and pragma syntax on the same statement" }
+  extern int f34 (int);
+}