Add parser+semantics support for scope construct (llvm#113700)

Test parsing, semantics and a couple of basic semantic checks for
block/worksharing constructs.
Add TODO message in lowering.

Author: kiranchandramohan

flang/include/flang/Semantics/openmp-directive-sets.h

@@ -211,6 +211,7 @@ static const OmpDirectiveSet blockConstructSet{
     Directive::OMPD_parallel,
     Directive::OMPD_parallel_masked,
     Directive::OMPD_parallel_workshare,
+    Directive::OMPD_scope,
     Directive::OMPD_single,
     Directive::OMPD_target,
     Directive::OMPD_target_data,
@@ -281,6 +282,7 @@ static const OmpDirectiveSet workShareSet{
         Directive::OMPD_workshare,
         Directive::OMPD_parallel_workshare,
         Directive::OMPD_parallel_sections,
+        Directive::OMPD_scope,
         Directive::OMPD_sections,
         Directive::OMPD_single,
     } | allDoSet,

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -1650,6 +1650,15 @@ genSectionsOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
   return sectionsOp;
 }
 
+static void genScopeOp(lower::AbstractConverter &converter,
+                       lower::SymMap &symTable,
+                       semantics::SemanticsContext &semaCtx,
+                       lower::pft::Evaluation &eval, mlir::Location loc,
+                       const ConstructQueue &queue,
+                       ConstructQueue::const_iterator item) {
+  TODO(loc, "Scope construct");
+}
+
 static mlir::omp::SingleOp
 genSingleOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
             semantics::SemanticsContext &semaCtx, lower::pft::Evaluation &eval,
@@ -2478,6 +2487,9 @@ static void genOMPDispatch(lower::AbstractConverter &converter,
   case llvm::omp::Directive::OMPD_simd:
     genStandaloneSimd(converter, symTable, semaCtx, eval, loc, queue, item);
     break;
+  case llvm::omp::Directive::OMPD_scope:
+    genScopeOp(converter, symTable, semaCtx, eval, loc, queue, item);
+    break;
   case llvm::omp::Directive::OMPD_single:
     genSingleOp(converter, symTable, semaCtx, eval, loc, queue, item);
     break;

flang/lib/Parser/openmp-parsers.cpp

@@ -697,6 +697,7 @@ TYPE_PARSER(construct<OmpBlockDirective>(first(
     "PARALLEL MASKED" >> pure(llvm::omp::Directive::OMPD_parallel_masked),
     "PARALLEL WORKSHARE" >> pure(llvm::omp::Directive::OMPD_parallel_workshare),
     "PARALLEL" >> pure(llvm::omp::Directive::OMPD_parallel),
+    "SCOPE" >> pure(llvm::omp::Directive::OMPD_scope),
     "SINGLE" >> pure(llvm::omp::Directive::OMPD_single),
     "TARGET DATA" >> pure(llvm::omp::Directive::OMPD_target_data),
     "TARGET PARALLEL" >> pure(llvm::omp::Directive::OMPD_target_parallel),

flang/lib/Parser/unparse.cpp

@@ -2386,6 +2386,9 @@ class UnparseVisitor {
     case llvm::omp::Directive::OMPD_parallel:
       Word("PARALLEL ");
       break;
+    case llvm::omp::Directive::OMPD_scope:
+      Word("SCOPE ");
+      break;
     case llvm::omp::Directive::OMPD_single:
       Word("SINGLE ");
       break;

flang/lib/Semantics/check-omp-structure.cpp

@@ -972,6 +972,7 @@ void OmpStructureChecker::Enter(const parser::OpenMPBlockConstruct &x) {
     HasInvalidWorksharingNesting(
         beginDir.source, llvm::omp::nestedWorkshareErrSet);
     break;
+  case llvm::omp::Directive::OMPD_scope:
   case llvm::omp::Directive::OMPD_single:
     // TODO: This check needs to be extended while implementing nesting of
     // regions checks.
@@ -1864,6 +1865,9 @@ void OmpStructureChecker::Enter(const parser::OmpEndBlockDirective &x) {
   const auto &dir{std::get<parser::OmpBlockDirective>(x.t)};
   ResetPartialContext(dir.source);
   switch (dir.v) {
+  case llvm::omp::Directive::OMPD_scope:
+    PushContextAndClauseSets(dir.source, llvm::omp::Directive::OMPD_end_scope);
+    break;
   // 2.7.3 end-single-clause -> copyprivate-clause |
   //                            nowait-clause
   case llvm::omp::Directive::OMPD_single:
@@ -1886,7 +1890,8 @@ void OmpStructureChecker::Enter(const parser::OmpEndBlockDirective &x) {
 // end_workshareare popped as they are pushed while entering the
 // EndBlockDirective.
 void OmpStructureChecker::Leave(const parser::OmpEndBlockDirective &x) {
-  if ((GetContext().directive == llvm::omp::Directive::OMPD_end_single) ||
+  if ((GetContext().directive == llvm::omp::Directive::OMPD_end_scope) ||
+      (GetContext().directive == llvm::omp::Directive::OMPD_end_single) ||
       (GetContext().directive == llvm::omp::Directive::OMPD_end_workshare)) {
     dirContext_.pop_back();
   }

flang/lib/Semantics/resolve-directives.cpp

@@ -1526,6 +1526,7 @@ bool OmpAttributeVisitor::Pre(const parser::OpenMPBlockConstruct &x) {
   case llvm::omp::Directive::OMPD_master:
   case llvm::omp::Directive::OMPD_ordered:
   case llvm::omp::Directive::OMPD_parallel:
+  case llvm::omp::Directive::OMPD_scope:
   case llvm::omp::Directive::OMPD_single:
   case llvm::omp::Directive::OMPD_target:
   case llvm::omp::Directive::OMPD_target_data:
@@ -1557,6 +1558,7 @@ void OmpAttributeVisitor::Post(const parser::OpenMPBlockConstruct &x) {
   case llvm::omp::Directive::OMPD_masked:
   case llvm::omp::Directive::OMPD_parallel_masked:
   case llvm::omp::Directive::OMPD_parallel:
+  case llvm::omp::Directive::OMPD_scope:
   case llvm::omp::Directive::OMPD_single:
   case llvm::omp::Directive::OMPD_target:
   case llvm::omp::Directive::OMPD_task:

flang/test/Lower/OpenMP/Todo/scope.f90

@@ -0,0 +1,13 @@
+! RUN: %not_todo_cmd bbc -emit-fir -fopenmp -o - %s -fopenmp-version=51 2>&1 | FileCheck %s
+! RUN: %not_todo_cmd %flang_fc1 -emit-fir -fopenmp -o - %s -fopenmp-version=51 2>&1 | FileCheck %s
+
+! CHECK: not yet implemented: Scope construct
+program omp_scope
+  integer i
+  i = 10
+
+  !$omp scope private(i)
+  print *, "omp scope", i
+  !$omp end scope
+
+end program omp_scope

flang/test/Parser/OpenMP/scope.f90

@@ -0,0 +1,24 @@
+! RUN: %flang_fc1 -fdebug-unparse -fopenmp -fopenmp-version=51 %s | FileCheck --ignore-case %s
+! RUN: %flang_fc1 -fdebug-dump-parse-tree -fopenmp -fopenmp-version=51 %s | FileCheck --check-prefix="PARSE-TREE" %s
+
+program omp_scope
+  integer i
+  i = 10
+
+!CHECK: !$OMP SCOPE  PRIVATE(i)
+!CHECK: !$OMP END SCOPE
+
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPBlockConstruct
+!PARSE-TREE: OmpBeginBlockDirective
+!PARSE-TREE: OmpBlockDirective -> llvm::omp::Directive = scope
+!PARSE-TREE: OmpClauseList -> OmpClause -> Private -> OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'i'
+!PARSE-TREE: Block
+!PARSE-TREE: ExecutionPartConstruct -> ExecutableConstruct -> ActionStmt -> PrintStmt
+!PARSE-TREE: OmpEndBlockDirective
+!PARSE-TREE: OmpBlockDirective -> llvm::omp::Directive = scope
+!PARSE-TREE: OmpClauseList -> OmpClause -> Nowait
+
+  !$omp scope private(i)
+  print *, "omp scope", i
+  !$omp end scope nowait
+end program omp_scope

flang/test/Semantics/OpenMP/invalid-branch.f90

@@ -105,4 +105,12 @@ program omp_invalid_branch
   !$omp end parallel
   9 print *, "2nd alternate return"
 
+  !CHECK: invalid branch into an OpenMP structured block
+  goto 100
+  !$omp scope
+    100 continue
+    !CHECK: invalid branch leaving an OpenMP structured block
+    goto 200
+  !$omp end scope
+  200 continue
 end program

flang/test/Semantics/OpenMP/nested01.f90

@@ -25,6 +25,13 @@
    !$omp end target
   enddo
 
+  !$omp do
+  do i = 1, N
+     !ERROR: A worksharing region may not be closely nested inside a worksharing, explicit task, taskloop, critical, ordered, atomic, or master region
+     !$omp scope
+     !$omp end scope
+  end do
+  !$omp end do
 
   !$omp do
   do i = 1, N