[Flang] [OpenMP] Add semantic checks for detach clause in task

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

@@ -2733,6 +2733,62 @@ void OmpStructureChecker::Leave(const parser::OmpClauseList &) {
         llvm::omp::Clause::OMPC_copyprivate, {llvm::omp::Clause::OMPC_nowait});
   }
 
+  if (GetContext().directive == llvm::omp::Directive::OMPD_task) {
+    if (auto *detachClause{FindClause(llvm::omp::Clause::OMPC_detach)}) {
+      unsigned version{context_.langOptions().OpenMPVersion};
+      if (version == 50 || version == 51) {
+        // OpenMP 5.0: 2.10.1 Task construct restrictions
+        CheckNotAllowedIfClause(
+            llvm::omp::Clause::OMPC_detach, {llvm::omp::Clause::OMPC_mergeable});
+      } else if (version >= 52) {
+        // OpenMP 5.2: 12.5.2 Detach construct restrictions
+        if (FindClause(llvm::omp::Clause::OMPC_final)) {
+          context_.Say(GetContext().clauseSource,
+              "If a DETACH clause appears on a directive, then the encountering task must not be a FINAL task"_err_en_US);
+        }
+
+        const auto &detach{
+            std::get<parser::OmpClause::Detach>(detachClause->u)};
+        if (const auto *name{parser::Unwrap<parser::Name>(detach.v.v)}) {
+          if (name->symbol) {
+            Symbol *eventHandleSym{name->symbol};
+            auto checkVarAppearsInDataEnvClause = [&](const parser::OmpObjectList
+                                                          &objs,
+                                                      std::string clause) {
+              for (const auto &obj : objs.v) {
+                if (const parser::Name *objName{
+                        parser::Unwrap<parser::Name>(obj)}) {
+                  if (&objName->symbol->GetUltimate() == eventHandleSym) {
+                    context_.Say(GetContext().clauseSource,
+                        "A variable: `%s` that appears in a DETACH clause cannot appear on %s clause on the same construct"_err_en_US,
+                        objName->source, clause);
+                  }
+                }
+              }
+            };
+            if (auto *dataEnvClause{
+                    FindClause(llvm::omp::Clause::OMPC_private)}) {
+              const auto &pClause{
+                  std::get<parser::OmpClause::Private>(dataEnvClause->u)};
+              checkVarAppearsInDataEnvClause(pClause.v, "PRIVATE");
+            } else if (auto *dataEnvClause{
+                          FindClause(llvm::omp::Clause::OMPC_firstprivate)}) {
+              const auto &fpClause{
+                  std::get<parser::OmpClause::Firstprivate>(dataEnvClause->u)};
+              checkVarAppearsInDataEnvClause(fpClause.v, "FIRSTPRIVATE");
+            } else if (auto *dataEnvClause{
+                          FindClause(llvm::omp::Clause::OMPC_in_reduction)}) {
+              const auto &irClause{
+                  std::get<parser::OmpClause::InReduction>(dataEnvClause->u)};
+              checkVarAppearsInDataEnvClause(
+                  std::get<parser::OmpObjectList>(irClause.v.t), "IN_REDUCTION");
+            }
+          }
+        }
+      }
+    }
+  }
+
   auto testThreadprivateVarErr = [&](Symbol sym, parser::Name name,
                                      llvmOmpClause clauseTy) {
     if (sym.test(Symbol::Flag::OmpThreadprivate))
@@ -2815,7 +2871,6 @@ CHECK_SIMPLE_CLAUSE(Capture, OMPC_capture)
 CHECK_SIMPLE_CLAUSE(Contains, OMPC_contains)
 CHECK_SIMPLE_CLAUSE(Default, OMPC_default)
 CHECK_SIMPLE_CLAUSE(Depobj, OMPC_depobj)
-CHECK_SIMPLE_CLAUSE(Detach, OMPC_detach)
 CHECK_SIMPLE_CLAUSE(DeviceType, OMPC_device_type)
 CHECK_SIMPLE_CLAUSE(DistSchedule, OMPC_dist_schedule)
 CHECK_SIMPLE_CLAUSE(Exclusive, OMPC_exclusive)
@@ -3386,40 +3441,45 @@ void OmpStructureChecker::CheckIsVarPartOfAnotherVar(
     const parser::CharBlock &source, const parser::OmpObjectList &objList,
     llvm::StringRef clause) {
   for (const auto &ompObject : objList.v) {
-    common::visit(
-        common::visitors{
-            [&](const parser::Designator &designator) {
-              if (const auto *dataRef{
-                      std::get_if<parser::DataRef>(&designator.u)}) {
-                if (IsDataRefTypeParamInquiry(dataRef)) {
+    CheckIsVarPartOfAnotherVar(source, ompObject, clause);
+  }
+}
+
+void OmpStructureChecker::CheckIsVarPartOfAnotherVar(
+    const parser::CharBlock &source, const parser::OmpObject &ompObject,
+    llvm::StringRef clause) {
+  common::visit(
+      common::visitors{
+          [&](const parser::Designator &designator) {
+            if (const auto *dataRef{
+                    std::get_if<parser::DataRef>(&designator.u)}) {
+              if (IsDataRefTypeParamInquiry(dataRef)) {
+                context_.Say(source,
+                    "A type parameter inquiry cannot appear on the %s "
+                    "directive"_err_en_US,
+                    ContextDirectiveAsFortran());
+              } else if (parser::Unwrap<parser::StructureComponent>(
+                             ompObject) ||
+                  parser::Unwrap<parser::ArrayElement>(ompObject)) {
+                if (llvm::omp::nonPartialVarSet.test(GetContext().directive)) {
                   context_.Say(source,
-                      "A type parameter inquiry cannot appear on the %s "
+                      "A variable that is part of another variable (as an "
+                      "array or structure element) cannot appear on the %s "
                       "directive"_err_en_US,
                       ContextDirectiveAsFortran());
-                } else if (parser::Unwrap<parser::StructureComponent>(
-                               ompObject) ||
-                    parser::Unwrap<parser::ArrayElement>(ompObject)) {
-                  if (llvm::omp::nonPartialVarSet.test(
-                          GetContext().directive)) {
-                    context_.Say(source,
-                        "A variable that is part of another variable (as an "
-                        "array or structure element) cannot appear on the %s "
-                        "directive"_err_en_US,
-                        ContextDirectiveAsFortran());
-                  } else {
-                    context_.Say(source,
-                        "A variable that is part of another variable (as an "
-                        "array or structure element) cannot appear in a "
-                        "%s clause"_err_en_US,
-                        clause.data());
-                  }
+                } else {
+                  context_.Say(source,
+                      "A variable that is part of another variable (as an "
+                      "array or structure element) cannot appear in a "
+                      "%s clause"_err_en_US,
+                      clause.data());
                 }
               }
-            },
-            [&](const parser::Name &name) {},
-        },
-        ompObject.u);
-  }
+            }
+          },
+          [&](const parser::Name &name) {},
+      },
+      ompObject.u);
 }
 
 void OmpStructureChecker::Enter(const parser::OmpClause::Firstprivate &x) {
@@ -3746,6 +3806,30 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Linear &x) {
   }
 }
 
+void OmpStructureChecker::Enter(const parser::OmpClause::Detach &x) {
+  CheckAllowedClause(llvm::omp::Clause::OMPC_detach);
+  unsigned version{context_.langOptions().OpenMPVersion};
+  // OpenMP 5.2: 12.5.2 Detach clause restrictions
+  if (version >= 52) {
+    CheckIsVarPartOfAnotherVar(GetContext().clauseSource, x.v.v, "DETACH");
+  }
+
+  if (const auto *name{parser::Unwrap<parser::Name>(x.v.v)}) {
+    if (name->symbol) {
+      if (version >= 52 && IsPointer(*name->symbol)) {
+        context_.Say(GetContext().clauseSource,
+            "The event-handle: `%s` must not have the POINTER attribute"_err_en_US,
+            name->ToString());
+      }
+      if (!name->symbol->GetType()->IsNumeric(TypeCategory::Integer)) {
+        context_.Say(GetContext().clauseSource,
+            "The event-handle: `%s` must be of type integer(kind=omp_event_handle_kind)"_err_en_US,
+            name->ToString());
+      }
+    }
+  }
+}
+
 void OmpStructureChecker::CheckAllowedMapTypes(
     const parser::OmpMapType::Value &type,
     const std::list<parser::OmpMapType::Value> &allowedMapTypeList) {

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

@@ -186,6 +186,8 @@ class OmpStructureChecker
       const common::Indirection<parser::ArrayElement> &, const parser::Name &);
   void CheckDoacross(const parser::OmpDoacross &doa);
   bool IsDataRefTypeParamInquiry(const parser::DataRef *dataRef);
+  void CheckIsVarPartOfAnotherVar(const parser::CharBlock &source,
+      const parser::OmpObject &obj, llvm::StringRef clause = "");
   void CheckIsVarPartOfAnotherVar(const parser::CharBlock &source,
       const parser::OmpObjectList &objList, llvm::StringRef clause = "");
   void CheckThreadprivateOrDeclareTargetVar(

flang/test/Semantics/OpenMP/detach01.f90

@@ -0,0 +1,53 @@
+! REQUIRES: openmp_runtime
+! RUN: %python %S/../test_errors.py %s %flang_fc1 %openmp_flags -fopenmp-version=52
+
+! OpenMP Version 5.2: 12.5.2
+! Various checks for DETACH Clause
+
+program detach01
+    use omp_lib, only: omp_event_handle_kind
+    implicit none
+    real                                    :: e, x
+    integer(omp_event_handle_kind)          :: event_01, event_02(2)
+    integer(omp_event_handle_kind), pointer :: event_03
+
+    type :: t
+        integer(omp_event_handle_kind) :: event
+    end type
+    type(t) :: t_01
+
+    !ERROR: The event-handle: `e` must be of type integer(kind=omp_event_handle_kind)
+    !$omp task detach(e)
+        x = x + 1
+    !$omp end task
+
+    !ERROR: If a DETACH clause appears on a directive, then the encountering task must not be a FINAL task
+    !$omp task detach(event_01) final(.false.)
+        x = x + 1
+    !$omp end task
+
+    !ERROR: A variable: `event_01` that appears in a DETACH clause cannot appear on PRIVATE clause on the same construct
+    !$omp task detach(event_01) private(event_01)
+        x = x + 1
+    !$omp end task
+
+    !ERROR: A variable: `event_01` that appears in a DETACH clause cannot appear on IN_REDUCTION clause on the same construct
+    !$omp task detach(event_01) in_reduction(+:event_01)
+        x = x + 1
+    !$omp end task
+
+    !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear in a DETACH clause
+    !$omp task detach(event_02(1))
+        x = x + 1
+    !$omp end task
+
+    !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear in a DETACH clause
+    !$omp task detach(t_01%event)
+        x = x + 1
+    !$omp end task
+
+    !ERROR: The event-handle: `event_03` must not have the POINTER attribute
+    !$omp task detach(event_03)
+        x = x + 1
+    !$omp end task
+end program

flang/test/Semantics/OpenMP/detach02.f90

@@ -0,0 +1,22 @@
+! REQUIRES: openmp_runtime
+! RUN: %python %S/../test_errors.py %s %flang_fc1 %openmp_flags -fopenmp-version=50
+! RUN: %python %S/../test_errors.py %s %flang_fc1 %openmp_flags -fopenmp-version=51
+
+! OpenMP Version 5.0: 2.10.1
+! Various checks for DETACH Clause
+
+program detach02
+    use omp_lib, only: omp_event_handle_kind
+    integer(omp_event_handle_kind)          :: event_01, event_02
+
+    !TODO: Throw following error for the versions 5.0 and 5.1
+    !ERR: At most one DETACH clause can appear on the TASK directive
+    !!$omp task detach(event_01) detach(event_02)
+    !    x = x + 1
+    !!$omp end task
+
+    !ERROR: Clause MERGEABLE is not allowed if clause DETACH appears on the TASK directive
+    !$omp task detach(event_01) mergeable
+        x = x + 1
+    !$omp end task
+end program