[flang][OpenMP] Allow utility constructs in specification part

flang/examples/FlangOmpReport/FlangOmpReportVisitor.cpp

@@ -90,6 +90,10 @@ SourcePosition OpenMPCounterVisitor::getLocation(const OpenMPConstruct &c) {
             const CharBlock &source{c.source};
             return (parsing->allCooked().GetSourcePositionRange(source))->first;
           },
+          [&](const OpenMPUtilityConstruct &c) -> SourcePosition {
+            const CharBlock &source{c.source};
+            return (parsing->allCooked().GetSourcePositionRange(source))->first;
+          },
       },
       c.u);
 }
@@ -102,10 +106,16 @@ std::string OpenMPCounterVisitor::getName(const OmpWrapperType &w) {
   return getName(*std::get<const OpenMPDeclarativeConstruct *>(w));
 }
 std::string OpenMPCounterVisitor::getName(const OpenMPDeclarativeConstruct &c) {
-  return std::visit(
-      [&](const auto &o) -> std::string {
-        const CharBlock &source{std::get<Verbatim>(o.t).source};
-        return normalize_construct_name(source.ToString());
+  return std::visit( //
+      Fortran::common::visitors{
+          [&](const OpenMPUtilityConstruct &o) -> std::string {
+            const CharBlock &source{o.source};
+            return normalize_construct_name(source.ToString());
+          },
+          [&](const auto &o) -> std::string {
+            const CharBlock &source{std::get<Verbatim>(o.t).source};
+            return normalize_construct_name(source.ToString());
+          },
       },
       c.u);
 }
@@ -143,8 +153,8 @@ std::string OpenMPCounterVisitor::getName(const OpenMPConstruct &c) {
                 },
                 c.u);
           },
-          [&](const OpenMPErrorConstruct &c) -> std::string {
-            const CharBlock &source{std::get<0>(c.t).source};
+          [&](const OpenMPUtilityConstruct &c) -> std::string {
+            const CharBlock &source{c.source};
             return normalize_construct_name(source.ToString());
           },
           [&](const OpenMPSectionConstruct &c) -> std::string {

flang/include/flang/Parser/dump-parse-tree.h

@@ -516,6 +516,8 @@ class ParseTreeDumper {
 #include "llvm/Frontend/OpenMP/OMP.inc"
   NODE(parser, OmpClauseList)
   NODE(parser, OmpCriticalDirective)
+  NODE(parser, OmpErrorDirective)
+  NODE(parser, OmpNothingDirective)
   NODE(parser, OmpDeclareTargetSpecifier)
   NODE(parser, OmpDeclareTargetWithClause)
   NODE(parser, OmpDeclareTargetWithList)
@@ -662,7 +664,7 @@ class ParseTreeDumper {
   NODE(parser, OmpAtomicDefaultMemOrderClause)
   NODE_ENUM(common, OmpAtomicDefaultMemOrderType)
   NODE(parser, OpenMPDepobjConstruct)
-  NODE(parser, OpenMPErrorConstruct)
+  NODE(parser, OpenMPUtilityConstruct)
   NODE(parser, OpenMPFlushConstruct)
   NODE(parser, OpenMPLoopConstruct)
   NODE(parser, OpenMPExecutableAllocate)

flang/include/flang/Parser/parse-tree.h

@@ -4182,6 +4182,30 @@ struct OmpClauseList {
 
 // --- Directives and constructs
 
+// Ref: [5.1:89-90], [5.2:216]
+//
+// nothing-directive ->
+//    NOTHING                                     // since 5.1
+struct OmpNothingDirective {
+  using EmptyTrait = std::true_type;
+  COPY_AND_ASSIGN_BOILERPLATE(OmpNothingDirective);
+  CharBlock source;
+};
+
+// Ref: OpenMP [5.2:216-218]
+// ERROR AT(compilation|execution) SEVERITY(fatal|warning) MESSAGE("msg-str)
+struct OmpErrorDirective {
+  TUPLE_CLASS_BOILERPLATE(OmpErrorDirective);
+  CharBlock source;
+  std::tuple<Verbatim, OmpClauseList> t;
+};
+
+struct OpenMPUtilityConstruct {
+  UNION_CLASS_BOILERPLATE(OpenMPUtilityConstruct);
+  CharBlock source;
+  std::variant<OmpErrorDirective, OmpNothingDirective> u;
+};
+
 // 2.7.2 SECTIONS
 // 2.11.2 PARALLEL SECTIONS
 struct OmpSectionsDirective {
@@ -4318,7 +4342,7 @@ struct OpenMPDeclarativeConstruct {
   std::variant<OpenMPDeclarativeAllocate, OpenMPDeclareMapperConstruct,
       OpenMPDeclareReductionConstruct, OpenMPDeclareSimdConstruct,
       OpenMPDeclareTargetConstruct, OpenMPThreadprivate,
-      OpenMPRequiresConstruct>
+      OpenMPRequiresConstruct, OpenMPUtilityConstruct>
       u;
 };
 
@@ -4506,14 +4530,6 @@ struct OpenMPDepobjConstruct {
   std::tuple<Verbatim, OmpObject, OmpClause> t;
 };
 
-// Ref: OpenMP [5.2:216-218]
-// ERROR AT(compilation|execution) SEVERITY(fatal|warning) MESSAGE("msg-str)
-struct OpenMPErrorConstruct {
-  TUPLE_CLASS_BOILERPLATE(OpenMPErrorConstruct);
-  CharBlock source;
-  std::tuple<Verbatim, OmpClauseList> t;
-};
-
 // 2.17.8 flush -> FLUSH [memory-order-clause] [(variable-name-list)]
 struct OpenMPFlushConstruct {
   TUPLE_CLASS_BOILERPLATE(OpenMPFlushConstruct);
@@ -4586,7 +4602,7 @@ struct OpenMPConstruct {
   UNION_CLASS_BOILERPLATE(OpenMPConstruct);
   std::variant<OpenMPStandaloneConstruct, OpenMPSectionsConstruct,
       OpenMPSectionConstruct, OpenMPLoopConstruct, OpenMPBlockConstruct,
-      OpenMPAtomicConstruct, OpenMPDeclarativeAllocate, OpenMPErrorConstruct,
+      OpenMPAtomicConstruct, OpenMPDeclarativeAllocate, OpenMPUtilityConstruct,
       OpenMPExecutableAllocate, OpenMPAllocatorsConstruct,
       OpenMPCriticalConstruct>
       u;

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -2586,6 +2586,10 @@ static void genOMPDispatch(lower::AbstractConverter &converter,
 //===----------------------------------------------------------------------===//
 // OpenMPDeclarativeConstruct visitors
 //===----------------------------------------------------------------------===//
+static void genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
+                   semantics::SemanticsContext &semaCtx,
+                   lower::pft::Evaluation &eval,
+                   const parser::OpenMPUtilityConstruct &);
 
 static void
 genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
@@ -2907,8 +2911,8 @@ static void genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
 static void genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
                    semantics::SemanticsContext &semaCtx,
                    lower::pft::Evaluation &eval,
-                   const parser::OpenMPErrorConstruct &) {
-  TODO(converter.getCurrentLocation(), "OpenMPErrorConstruct");
+                   const parser::OpenMPUtilityConstruct &) {
+  TODO(converter.getCurrentLocation(), "OpenMPUtilityConstruct");
 }
 
 static void genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,

flang/lib/Parser/openmp-parsers.cpp

@@ -737,9 +737,20 @@ TYPE_PARSER(
 TYPE_PARSER(sourced(construct<OmpClauseList>(
     many(maybe(","_tok) >> sourced(Parser<OmpClause>{})))))
 
-// 2.1 (variable | /common-block | array-sections)
+// 2.1 (variable | /common-block/ | array-sections)
 TYPE_PARSER(construct<OmpObjectList>(nonemptyList(Parser<OmpObject>{})))
 
+TYPE_PARSER(sourced(construct<OmpErrorDirective>(
+    verbatim("ERROR"_tok), Parser<OmpClauseList>{})))
+
+TYPE_PARSER(sourced(construct<OmpNothingDirective>("NOTHING" >> ok)))
+
+TYPE_PARSER(sourced(construct<OpenMPUtilityConstruct>(
+    sourced(construct<OpenMPUtilityConstruct>(
+        sourced(Parser<OmpErrorDirective>{}))) ||
+    sourced(construct<OpenMPUtilityConstruct>(
+        sourced(Parser<OmpNothingDirective>{}))))))
+
 // Omp directives enclosing do loop
 TYPE_PARSER(sourced(construct<OmpLoopDirective>(first(
     "DISTRIBUTE PARALLEL DO SIMD" >>
@@ -1027,9 +1038,6 @@ TYPE_PARSER(sourced(construct<OmpCriticalDirective>(verbatim("CRITICAL"_tok),
 TYPE_PARSER(construct<OpenMPCriticalConstruct>(
     Parser<OmpCriticalDirective>{}, block, Parser<OmpEndCriticalDirective>{}))
 
-TYPE_PARSER(sourced(construct<OpenMPErrorConstruct>(
-    verbatim("ERROR"_tok), Parser<OmpClauseList>{})))
-
 // 2.11.3 Executable Allocate directive
 TYPE_PARSER(
     sourced(construct<OpenMPExecutableAllocate>(verbatim("ALLOCATE"_tok),
@@ -1082,7 +1090,9 @@ TYPE_PARSER(startOmpLine >>
             construct<OpenMPDeclarativeConstruct>(
                 Parser<OpenMPRequiresConstruct>{}) ||
             construct<OpenMPDeclarativeConstruct>(
-                Parser<OpenMPThreadprivate>{})) /
+                Parser<OpenMPThreadprivate>{}) ||
+            construct<OpenMPDeclarativeConstruct>(
+                Parser<OpenMPUtilityConstruct>{})) /
             endOmpLine))
 
 // Block Construct
@@ -1127,7 +1137,7 @@ TYPE_CONTEXT_PARSER("OpenMP construct"_en_US,
                 // OpenMPStandaloneConstruct to resolve !$OMP ORDERED
                 construct<OpenMPConstruct>(Parser<OpenMPStandaloneConstruct>{}),
                 construct<OpenMPConstruct>(Parser<OpenMPAtomicConstruct>{}),
-                construct<OpenMPConstruct>(Parser<OpenMPErrorConstruct>{}),
+                construct<OpenMPConstruct>(Parser<OpenMPUtilityConstruct>{}),
                 construct<OpenMPConstruct>(Parser<OpenMPExecutableAllocate>{}),
                 construct<OpenMPConstruct>(Parser<OpenMPAllocatorsConstruct>{}),
                 construct<OpenMPConstruct>(Parser<OpenMPDeclarativeAllocate>{}),

flang/lib/Parser/unparse.cpp

@@ -2631,90 +2631,77 @@ class UnparseVisitor {
     }
   }
   void Unparse(const OpenMPDeclareReductionConstruct &x) {
+    BeginOpenMP();
+    Word("!$OMP DECLARE REDUCTION ");
     Put("(");
     Walk(std::get<OmpReductionIdentifier>(x.t)), Put(" : ");
     Walk(std::get<std::list<DeclarationTypeSpec>>(x.t), ","), Put(" : ");
     Walk(std::get<OmpReductionCombiner>(x.t));
     Put(")");
     Walk(std::get<std::optional<OmpReductionInitializerClause>>(x.t));
+    EndOpenMP();
   }
-  bool Pre(const OpenMPDeclarativeConstruct &x) {
+
+  void Unparse(const OpenMPDeclareMapperConstruct &z) {
     BeginOpenMP();
-    Word("!$OMP ");
-    return common::visit(
-        common::visitors{
-            [&](const OpenMPDeclarativeAllocate &z) {
-              Word("ALLOCATE (");
-              Walk(std::get<OmpObjectList>(z.t));
-              Put(")");
-              Walk(std::get<OmpClauseList>(z.t));
-              Put("\n");
-              EndOpenMP();
-              return false;
-            },
-            [&](const OpenMPDeclareMapperConstruct &z) {
-              Word("DECLARE MAPPER (");
-              const auto &spec{std::get<OmpDeclareMapperSpecifier>(z.t)};
-              if (auto mapname{std::get<std::optional<Name>>(spec.t)}) {
-                Walk(mapname);
-                Put(":");
-              }
-              Walk(std::get<TypeSpec>(spec.t));
-              Put("::");
-              Walk(std::get<Name>(spec.t));
-              Put(")");
+    Word("!$OMP DECLARE MAPPER (");
+    const auto &spec{std::get<OmpDeclareMapperSpecifier>(z.t)};
+    if (auto mapname{std::get<std::optional<Name>>(spec.t)}) {
+      Walk(mapname);
+      Put(":");
+    }
+    Walk(std::get<TypeSpec>(spec.t));
+    Put("::");
+    Walk(std::get<Name>(spec.t));
+    Put(")");
 
-              Walk(std::get<OmpClauseList>(z.t));
-              Put("\n");
-              return false;
-            },
-            [&](const OpenMPDeclareReductionConstruct &) {
-              Word("DECLARE REDUCTION ");
-              return true;
-            },
-            [&](const OpenMPDeclareSimdConstruct &y) {
-              Word("DECLARE SIMD ");
-              Walk("(", std::get<std::optional<Name>>(y.t), ")");
-              Walk(std::get<OmpClauseList>(y.t));
-              Put("\n");
-              EndOpenMP();
-              return false;
-            },
-            [&](const OpenMPDeclareTargetConstruct &) {
-              Word("DECLARE TARGET ");
-              return true;
-            },
-            [&](const OpenMPRequiresConstruct &y) {
-              Word("REQUIRES ");
-              Walk(std::get<OmpClauseList>(y.t));
-              Put("\n");
-              EndOpenMP();
-              return false;
-            },
-            [&](const OpenMPThreadprivate &) {
-              Word("THREADPRIVATE (");
-              return true;
-            },
-        },
-        x.u);
+    Walk(std::get<OmpClauseList>(z.t));
+    Put("\n");
+    EndOpenMP();
+  }
+  void Unparse(const OpenMPDeclareSimdConstruct &y) {
+    BeginOpenMP();
+    Word("!$OMP DECLARE SIMD ");
+    Walk("(", std::get<std::optional<Name>>(y.t), ")");
+    Walk(std::get<OmpClauseList>(y.t));
+    Put("\n");
+    EndOpenMP();
   }
-  void Post(const OpenMPDeclarativeConstruct &) {
+  void Unparse(const OpenMPDeclareTargetConstruct &x) {
+    BeginOpenMP();
+    Word("!$OMP DECLARE TARGET ");
+    Walk(std::get<parser::OmpDeclareTargetSpecifier>(x.t));
     Put("\n");
     EndOpenMP();
   }
-  void Post(const OpenMPThreadprivate &) {
+  void Unparse(const OpenMPRequiresConstruct &y) {
+    BeginOpenMP();
+    Word("!$OMP REQUIRES ");
+    Walk(std::get<OmpClauseList>(y.t));
+    Put("\n");
+    EndOpenMP();
+  }
+  void Unparse(const OpenMPThreadprivate &x) {
+    BeginOpenMP();
+    Word("!$OMP THREADPRIVATE (");
+    Walk(std::get<parser::OmpObjectList>(x.t));
     Put(")\n");
     EndOpenMP();
   }
+
   bool Pre(const OmpMessageClause &x) {
     Walk(x.v);
     return false;
   }
-  void Unparse(const OpenMPErrorConstruct &x) {
+  void Unparse(const OmpErrorDirective &x) {
     Word("!$OMP ERROR ");
     Walk(x.t);
     Put("\n");
   }
+  void Unparse(const OmpNothingDirective &x) {
+    Word("!$OMP NOTHING");
+    Put("\n");
+  }
   void Unparse(const OmpSectionsDirective &x) {
     switch (x.v) {
     case llvm::omp::Directive::OMPD_sections: