[gcc/devel/omp/gcc-11] openmp: Handle OpenMP directives in attribute syntax in attribute-declaration

[Tobias Burnus <burnus@gcc.gnu.org>]

https://gcc.gnu.org/g:69b1e8c24d1c84322fb385d40aa930313aca710e

commit 69b1e8c24d1c84322fb385d40aa930313aca710e
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sun Aug 1 14:31:01 2021 +0200

    openmp: Handle OpenMP directives in attribute syntax in attribute-declaration
    
    Now that we parse attribute-declaration (outside of functions), the following
    patch handles OpenMP directives in its attribute(s).
    What needs handling incrementally is diagnose mismatching begin/end pair
    like
     [[omp::directive (declare target)]];
     int a;
     #pragma omp end declare target
    or
     #pragma omp declare target
     int b;
     [[omp::directive (end declare target)]];
    and handling declare simd/declare variant on declarations (function
    definitions and declarations), for those in two different spots.
    
    2021-07-31  Jakub Jelinek  <jakub@redhat.com>
    
            * parser.c (cp_parser_declaration): Handle OpenMP directives
            in attribute-declaration.
    
            * g++.dg/gomp/attrs-9.C: New test.
    
    (cherry picked from commit 05bcef5a88b34dd13179cabbe902e9135cb40ffe)

Diff:
---
 gcc/cp/ChangeLog.omp                |  8 ++++++++
 gcc/cp/parser.c                     | 19 +++++++++++++++++++
 gcc/testsuite/ChangeLog.omp         |  7 +++++++
 gcc/testsuite/g++.dg/gomp/attrs-9.C | 15 +++++++++++++++
 4 files changed, 49 insertions(+)

diff --git a/gcc/cp/ChangeLog.omp b/gcc/cp/ChangeLog.omp
index c7c267aae69..278c9aa67fd 100644
--- a/gcc/cp/ChangeLog.omp
+++ b/gcc/cp/ChangeLog.omp
@@ -1,3 +1,11 @@
+2021-08-01  Tobias Burnus  <tobias@codesourcery.com>
+
+	Backported from master:
+	2021-07-31  Jakub Jelinek  <jakub@redhat.com>
+
+	* parser.c (cp_parser_declaration): Handle OpenMP directives
+	in attribute-declaration.
+
 2021-07-30  Tobias Burnus  <tobias@codesourcery.com>
 
 	Backported from master:
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 0e62c5b69fd..4c73128a11b 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -14300,6 +14300,25 @@ cp_parser_declaration (cp_parser* parser, tree prefix_attrs)
     {
       location_t attrs_loc = token1->location;
       tree std_attrs = cp_parser_std_attribute_spec_seq (parser);
+
+      if (std_attrs && (flag_openmp || flag_openmp_simd))
+	{
+	  gcc_assert (!parser->lexer->in_omp_attribute_pragma);
+	  std_attrs = cp_parser_handle_statement_omp_attributes (parser,
+								 std_attrs);
+	  if (parser->lexer->in_omp_attribute_pragma)
+	    {
+	      cp_lexer *lexer = parser->lexer;
+	      while (parser->lexer->in_omp_attribute_pragma)
+		{
+		  gcc_assert (cp_lexer_next_token_is (parser->lexer,
+						      CPP_PRAGMA));
+		  cp_parser_pragma (parser, pragma_external, NULL);
+		}
+	      cp_lexer_destroy (lexer);
+	    }
+	}
+
       if (std_attrs != NULL_TREE)
 	warning_at (make_location (attrs_loc, attrs_loc, parser->lexer),
 		    OPT_Wattributes, "attribute ignored");
diff --git a/gcc/testsuite/ChangeLog.omp b/gcc/testsuite/ChangeLog.omp
index 6437bc32db8..300a9a75f9a 100644
--- a/gcc/testsuite/ChangeLog.omp
+++ b/gcc/testsuite/ChangeLog.omp
@@ -1,3 +1,10 @@
+2021-08-01  Tobias Burnus  <tobias@codesourcery.com>
+
+	Backported from master:
+	2021-07-31  Jakub Jelinek  <jakub@redhat.com>
+
+	* g++.dg/gomp/attrs-9.C: New test.
+
 2021-07-30  Tobias Burnus  <tobias@codesourcery.com>
 
 	Backported from master:
diff --git a/gcc/testsuite/g++.dg/gomp/attrs-9.C b/gcc/testsuite/g++.dg/gomp/attrs-9.C
new file mode 100644
index 00000000000..0af556c7284
--- /dev/null
+++ b/gcc/testsuite/g++.dg/gomp/attrs-9.C
@@ -0,0 +1,15 @@
+// { dg-do compile { target c++11 } }
+
+[[omp::sequence (directive (requires, atomic_default_mem_order (seq_cst)))]];
+[[omp::directive (declare reduction (plus: int: omp_out += omp_in) initializer (omp_priv = 0))]];
+int a;
+[[omp::directive (declare target (a))]];
+int t;
+[[omp::sequence (omp::directive (threadprivate (t)))]];
+int b, c;
+[[omp::directive (declare target, to (b), link (c))]];
+[[omp::directive (declare target)]];
+[[omp::directive (declare target)]];
+int d;
+[[omp::directive (end declare target)]];
+[[omp::directive (end declare target)]];