[flang][OpenMP] Add semantic check for declare target (#71861)

This patch adds the following check from OpenMP 5.2.

```
If the directive has a clause, it must contain at least one enter clause
or at least one link clause.
```

Also added a warning for the deprication of `TO` clause on `DECLARE
TARGET` construct.

```
The clause-name to may be used as a synonym for the clause-name enter.
This use has been deprecated.
```

Based on the tests for to clause, the tests for enter clause are added.

This patch does not add tests where both to and enter clause are used together.

flang/lib/Lower/OpenMP.cpp

@@ -590,6 +590,8 @@ public:
   bool processSectionsReduction(mlir::Location currentLocation) const;
   bool processTo(llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const;
   bool
+  processEnter(llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const;
+  bool
   processUseDeviceAddr(llvm::SmallVectorImpl<mlir::Value> &operands,
                        llvm::SmallVectorImpl<mlir::Type> &useDeviceTypes,
                        llvm::SmallVectorImpl<mlir::Location> &useDeviceLocs,
@@ -1851,6 +1853,18 @@ bool ClauseProcessor::processTo(
       });
 }
 
+bool ClauseProcessor::processEnter(
+    llvm::SmallVectorImpl<DeclareTargetCapturePair> &result) const {
+  return findRepeatableClause<ClauseTy::Enter>(
+      [&](const ClauseTy::Enter *enterClause,
+          const Fortran::parser::CharBlock &) {
+        // Case: declare target to(func, var1, var2)...
+        gatherFuncAndVarSyms(enterClause->v,
+                             mlir::omp::DeclareTargetCaptureClause::enter,
+                             result);
+      });
+}
+
 bool ClauseProcessor::processUseDeviceAddr(
     llvm::SmallVectorImpl<mlir::Value> &operands,
     llvm::SmallVectorImpl<mlir::Type> &useDeviceTypes,
@@ -2792,6 +2806,7 @@ static mlir::omp::DeclareTargetDeviceType getDeclareTargetInfo(
 
     ClauseProcessor cp(converter, *clauseList);
     cp.processTo(symbolAndClause);
+    cp.processEnter(symbolAndClause);
     cp.processLink(symbolAndClause);
     cp.processDeviceType(deviceType);
     cp.processTODO<Fortran::parser::OmpClause::Indirect>(

flang/lib/Parser/openmp-parsers.cpp

@@ -259,6 +259,8 @@ TYPE_PARSER(
             parenthesized("STATIC" >> maybe("," >> scalarIntExpr)))) ||
     "DYNAMIC_ALLOCATORS" >>
         construct<OmpClause>(construct<OmpClause::DynamicAllocators>()) ||
+    "ENTER" >> construct<OmpClause>(construct<OmpClause::Enter>(
+                   parenthesized(Parser<OmpObjectList>{}))) ||
     "FINAL" >> construct<OmpClause>(construct<OmpClause::Final>(
                    parenthesized(scalarLogicalExpr))) ||
     "FULL" >> construct<OmpClause>(construct<OmpClause::Full>()) ||

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

@@ -1165,13 +1165,31 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Allocate &x) {
   }
 }
 
+void OmpStructureChecker::Enter(const parser::OmpDeclareTargetWithClause &x) {
+  SetClauseSets(llvm::omp::Directive::OMPD_declare_target);
+}
+
+void OmpStructureChecker::Leave(const parser::OmpDeclareTargetWithClause &x) {
+  if (x.v.v.size() > 0) {
+    const parser::OmpClause *enterClause =
+        FindClause(llvm::omp::Clause::OMPC_enter);
+    const parser::OmpClause *toClause = FindClause(llvm::omp::Clause::OMPC_to);
+    const parser::OmpClause *linkClause =
+        FindClause(llvm::omp::Clause::OMPC_link);
+    if (!enterClause && !toClause && !linkClause) {
+      context_.Say(x.source,
+          "If the DECLARE TARGET directive has a clause, it must contain at lease one ENTER clause or LINK clause"_err_en_US);
+    }
+    if (toClause) {
+      context_.Say(toClause->source,
+          "The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead."_warn_en_US);
+    }
+  }
+}
+
 void OmpStructureChecker::Enter(const parser::OpenMPDeclareTargetConstruct &x) {
   const auto &dir{std::get<parser::Verbatim>(x.t)};
   PushContext(dir.source, llvm::omp::Directive::OMPD_declare_target);
-  const auto &spec{std::get<parser::OmpDeclareTargetSpecifier>(x.t)};
-  if (std::holds_alternative<parser::OmpDeclareTargetWithClause>(spec.u)) {
-    SetClauseSets(llvm::omp::Directive::OMPD_declare_target);
-  }
 }
 
 void OmpStructureChecker::Enter(const parser::OmpDeclareTargetWithList &x) {
@@ -1245,7 +1263,8 @@ void OmpStructureChecker::Leave(const parser::OpenMPDeclareTargetConstruct &x) {
     CheckThreadprivateOrDeclareTargetVar(*objectList);
   } else if (const auto *clauseList{
                  parser::Unwrap<parser::OmpClauseList>(spec.u)}) {
-    bool toClauseFound{false}, deviceTypeClauseFound{false};
+    bool toClauseFound{false}, deviceTypeClauseFound{false},
+        enterClauseFound{false};
     for (const auto &clause : clauseList->v) {
       common::visit(
           common::visitors{
@@ -1260,6 +1279,12 @@ void OmpStructureChecker::Leave(const parser::OpenMPDeclareTargetConstruct &x) {
                 CheckIsVarPartOfAnotherVar(dir.source, linkClause.v);
                 CheckThreadprivateOrDeclareTargetVar(linkClause.v);
               },
+              [&](const parser::OmpClause::Enter &enterClause) {
+                enterClauseFound = true;
+                CheckSymbolNames(dir.source, enterClause.v);
+                CheckIsVarPartOfAnotherVar(dir.source, enterClause.v);
+                CheckThreadprivateOrDeclareTargetVar(enterClause.v);
+              },
               [&](const parser::OmpClause::DeviceType &deviceTypeClause) {
                 deviceTypeClauseFound = true;
                 if (deviceTypeClause.v.v !=
@@ -1273,7 +1298,7 @@ void OmpStructureChecker::Leave(const parser::OpenMPDeclareTargetConstruct &x) {
           },
           clause.u);
 
-      if (toClauseFound && !deviceTypeClauseFound) {
+      if ((toClauseFound || enterClauseFound) && !deviceTypeClauseFound) {
         deviceConstructFound_ = true;
       }
     }
@@ -2228,6 +2253,7 @@ CHECK_SIMPLE_CLAUSE(CancellationConstructType, OMPC_cancellation_construct_type)
 CHECK_SIMPLE_CLAUSE(Doacross, OMPC_doacross)
 CHECK_SIMPLE_CLAUSE(OmpxAttribute, OMPC_ompx_attribute)
 CHECK_SIMPLE_CLAUSE(OmpxBare, OMPC_ompx_bare)
+CHECK_SIMPLE_CLAUSE(Enter, OMPC_enter)
 
 CHECK_REQ_SCALAR_INT_CLAUSE(Grainsize, OMPC_grainsize)
 CHECK_REQ_SCALAR_INT_CLAUSE(NumTasks, OMPC_num_tasks)
@@ -3229,12 +3255,13 @@ const parser::OmpObjectList *OmpStructureChecker::GetOmpObjectList(
     const parser::OmpClause &clause) {
 
   // Clauses with OmpObjectList as its data member
-  using MemberObjectListClauses = std::tuple<parser::OmpClause::Copyprivate,
-      parser::OmpClause::Copyin, parser::OmpClause::Firstprivate,
-      parser::OmpClause::From, parser::OmpClause::Lastprivate,
-      parser::OmpClause::Link, parser::OmpClause::Private,
-      parser::OmpClause::Shared, parser::OmpClause::To,
-      parser::OmpClause::UseDevicePtr, parser::OmpClause::UseDeviceAddr>;
+  using MemberObjectListClauses =
+      std::tuple<parser::OmpClause::Copyprivate, parser::OmpClause::Copyin,
+          parser::OmpClause::Firstprivate, parser::OmpClause::From,
+          parser::OmpClause::Lastprivate, parser::OmpClause::Link,
+          parser::OmpClause::Private, parser::OmpClause::Shared,
+          parser::OmpClause::To, parser::OmpClause::Enter,
+          parser::OmpClause::UseDevicePtr, parser::OmpClause::UseDeviceAddr>;
 
   // Clauses with OmpObjectList in the tuple
   using TupleObjectListClauses =

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

@@ -80,6 +80,8 @@ public:
   void Enter(const parser::OpenMPDeclareTargetConstruct &);
   void Leave(const parser::OpenMPDeclareTargetConstruct &);
   void Enter(const parser::OmpDeclareTargetWithList &);
+  void Enter(const parser::OmpDeclareTargetWithClause &);
+  void Leave(const parser::OmpDeclareTargetWithClause &);
   void Enter(const parser::OpenMPExecutableAllocate &);
   void Leave(const parser::OpenMPExecutableAllocate &);
   void Enter(const parser::OpenMPAllocatorsConstruct &);

flang/lib/Semantics/resolve-directives.cpp

@@ -1744,6 +1744,9 @@ bool OmpAttributeVisitor::Pre(const parser::OpenMPDeclareTargetConstruct &x) {
       } else if (const auto *linkClause{
                      std::get_if<parser::OmpClause::Link>(&clause.u)}) {
         ResolveOmpObjectList(linkClause->v, Symbol::Flag::OmpDeclareTarget);
+      } else if (const auto *enterClause{
+                     std::get_if<parser::OmpClause::Enter>(&clause.u)}) {
+        ResolveOmpObjectList(enterClause->v, Symbol::Flag::OmpDeclareTarget);
       }
     }
   }

flang/test/Lower/OpenMP/FIR/declare-target-data.f90

@@ -32,6 +32,10 @@ INTEGER, POINTER :: pt2 => pt2_tar
 INTEGER :: data_int_to = 5
 !$omp declare target to(data_int_to)
 
+!CHECK-DAG: fir.global @_QMtest_0Edata_int_enter {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : i32
+INTEGER :: data_int_enter = 5
+!$omp declare target enter(data_int_enter)
+
 !CHECK-DAG: fir.global @_QMtest_0Edata_int_clauseless {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>} : i32
 INTEGER :: data_int_clauseless = 1
 !$omp declare target(data_int_clauseless)
@@ -42,6 +46,12 @@ REAL :: data_extended_to_1 = 2
 REAL :: data_extended_to_2 = 3
 !$omp declare target to(data_extended_to_1, data_extended_to_2)
 
+!CHECK-DAG: fir.global @_QMtest_0Edata_extended_enter_1 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : f32
+!CHECK-DAG: fir.global @_QMtest_0Edata_extended_enter_2 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : f32
+REAL :: data_extended_enter_1 = 2
+REAL :: data_extended_enter_2 = 3
+!$omp declare target enter(data_extended_enter_1, data_extended_enter_2)
+
 !CHECK-DAG: fir.global @_QMtest_0Edata_extended_link_1 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (link)>} : f32
 !CHECK-DAG: fir.global @_QMtest_0Edata_extended_link_2 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (link)>} : f32
 REAL :: data_extended_link_1 = 2
@@ -69,4 +79,10 @@ PROGRAM commons
     REAL :: two_to = 2
     COMMON /numbers_to/ one_to, two_to
     !$omp declare target to(/numbers_to/)
+
+    !CHECK-DAG: fir.global @numbers_enter_ {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : tuple<f32, f32> {
+    REAL :: one_enter = 1
+    REAL :: two_enter = 2
+    COMMON /numbers_enter/ one_enter, two_enter
+    !$omp declare target enter(/numbers_enter/)
 END

flang/test/Lower/OpenMP/FIR/declare-target-func-and-subr.f90

@@ -13,6 +13,14 @@ FUNCTION FUNC_T_DEVICE() RESULT(I)
     I = 1
 END FUNCTION FUNC_T_DEVICE
 
+! DEVICE-LABEL: func.func @_QPfunc_enter_device()
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_ENTER_DEVICE() RESULT(I)
+!$omp declare target enter(FUNC_ENTER_DEVICE) device_type(nohost)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_ENTER_DEVICE
+
 ! HOST-LABEL: func.func @_QPfunc_t_host()
 ! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_T_HOST() RESULT(I)
@@ -21,6 +29,14 @@ FUNCTION FUNC_T_HOST() RESULT(I)
     I = 1
 END FUNCTION FUNC_T_HOST
 
+! HOST-LABEL: func.func @_QPfunc_enter_host()
+! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_ENTER_HOST() RESULT(I)
+!$omp declare target enter(FUNC_ENTER_HOST) device_type(host)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_ENTER_HOST
+
 ! ALL-LABEL: func.func @_QPfunc_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_T_ANY() RESULT(I)
@@ -29,6 +45,14 @@ FUNCTION FUNC_T_ANY() RESULT(I)
     I = 1
 END FUNCTION FUNC_T_ANY
 
+! ALL-LABEL: func.func @_QPfunc_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_ENTER_ANY() RESULT(I)
+!$omp declare target enter(FUNC_ENTER_ANY) device_type(any)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_ENTER_ANY
+
 ! ALL-LABEL: func.func @_QPfunc_default_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_DEFAULT_T_ANY() RESULT(I)
@@ -37,6 +61,14 @@ FUNCTION FUNC_DEFAULT_T_ANY() RESULT(I)
     I = 1
 END FUNCTION FUNC_DEFAULT_T_ANY
 
+! ALL-LABEL: func.func @_QPfunc_default_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_DEFAULT_ENTER_ANY() RESULT(I)
+!$omp declare target enter(FUNC_DEFAULT_ENTER_ANY)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_DEFAULT_ENTER_ANY
+
 ! ALL-LABEL: func.func @_QPfunc_default_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_DEFAULT_ANY() RESULT(I)
@@ -65,24 +97,48 @@ SUBROUTINE SUBR_T_DEVICE()
 !$omp declare target to(SUBR_T_DEVICE) device_type(nohost)
 END
 
+! DEVICE-LABEL: func.func @_QPsubr_enter_device()
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_ENTER_DEVICE()
+!$omp declare target enter(SUBR_ENTER_DEVICE) device_type(nohost)
+END
+
 ! HOST-LABEL: func.func @_QPsubr_t_host()
 ! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_T_HOST()
 !$omp declare target to(SUBR_T_HOST) device_type(host)
 END
 
+! HOST-LABEL: func.func @_QPsubr_enter_host()
+! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_ENTER_HOST()
+!$omp declare target enter(SUBR_ENTER_HOST) device_type(host)
+END
+
 ! ALL-LABEL: func.func @_QPsubr_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_T_ANY()
 !$omp declare target to(SUBR_T_ANY) device_type(any)
 END
 
+! ALL-LABEL: func.func @_QPsubr_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_ENTER_ANY()
+!$omp declare target enter(SUBR_ENTER_ANY) device_type(any)
+END
+
 ! ALL-LABEL: func.func @_QPsubr_default_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_DEFAULT_T_ANY()
 !$omp declare target to(SUBR_DEFAULT_T_ANY)
 END
 
+! ALL-LABEL: func.func @_QPsubr_default_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_DEFAULT_ENTER_ANY()
+!$omp declare target enter(SUBR_DEFAULT_ENTER_ANY)
+END
+
 ! ALL-LABEL: func.func @_QPsubr_default_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_DEFAULT_ANY()
@@ -108,3 +164,15 @@ RECURSIVE FUNCTION RECURSIVE_DECLARE_TARGET(INCREMENT) RESULT(K)
         K = RECURSIVE_DECLARE_TARGET(INCREMENT + 1)
     END IF
 END FUNCTION RECURSIVE_DECLARE_TARGET
+
+! DEVICE-LABEL: func.func @_QPrecursive_declare_target_enter
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}
+RECURSIVE FUNCTION RECURSIVE_DECLARE_TARGET_ENTER(INCREMENT) RESULT(K)
+!$omp declare target enter(RECURSIVE_DECLARE_TARGET_ENTER) device_type(nohost)
+    INTEGER :: INCREMENT, K
+    IF (INCREMENT == 10) THEN
+        K = INCREMENT
+    ELSE
+        K = RECURSIVE_DECLARE_TARGET_ENTER(INCREMENT + 1)
+    END IF
+END FUNCTION RECURSIVE_DECLARE_TARGET_ENTER

flang/test/Lower/OpenMP/FIR/declare-target-implicit-func-and-subr-cap-enter.f90

@@ -0,0 +1,192 @@
+!RUN: %flang_fc1 -emit-fir -fopenmp %s -o - | FileCheck %s
+!RUN: %flang_fc1 -emit-fir -fopenmp -fopenmp-is-target-device %s -o - | FileCheck %s  --check-prefix=DEVICE
+!RUN: bbc -emit-fir -fopenmp %s -o - | FileCheck %s
+!RUN: bbc -emit-fir -fopenmp -fopenmp-is-target-device %s -o - | FileCheck %s --check-prefix=DEVICE
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_twice() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_twice
+
+! CHECK-LABEL: func.func @_QPtarget_function_twice_host
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}}
+function target_function_twice_host() result(i)
+!$omp declare target enter(target_function_twice_host) device_type(host)
+   integer :: i
+   i = implicitly_captured_twice()
+end function target_function_twice_host
+
+! DEVICE-LABEL: func.func @_QPtarget_function_twice_device
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_twice_device() result(i)
+!$omp declare target enter(target_function_twice_device) device_type(nohost)
+   integer :: i
+   i = implicitly_captured_twice()
+end function target_function_twice_device
+
+!! -----
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_nest
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_nest() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_nest
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_one
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter){{.*}}}
+function implicitly_captured_one() result(k)
+   k = implicitly_captured_nest()
+end function implicitly_captured_one
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_two
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_two() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_two
+
+! DEVICE-LABEL: func.func @_QPtarget_function_test
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_test() result(j)
+!$omp declare target enter(target_function_test) device_type(nohost)
+   integer :: i, j
+   i = implicitly_captured_one()
+   j = implicitly_captured_two() + i
+end function target_function_test
+
+!! -----
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_nest_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_nest_twice() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_nest_twice
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_one_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_one_twice() result(k)
+   k = implicitly_captured_nest_twice()
+end function implicitly_captured_one_twice
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_two_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_two_twice() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_two_twice
+
+! DEVICE-LABEL: func.func @_QPtarget_function_test_device
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_test_device() result(j)
+   !$omp declare target enter(target_function_test_device) device_type(nohost)
+   integer :: i, j
+   i = implicitly_captured_one_twice()
+   j = implicitly_captured_two_twice() + i
+end function target_function_test_device
+
+! CHECK-LABEL: func.func @_QPtarget_function_test_host
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}}
+function target_function_test_host() result(j)
+   !$omp declare target enter(target_function_test_host) device_type(host)
+   integer :: i, j
+   i = implicitly_captured_one_twice()
+   j = implicitly_captured_two_twice() + i
+end function target_function_test_host
+
+!! -----
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_with_dev_type_recursive
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+recursive function implicitly_captured_with_dev_type_recursive(increment) result(k)
+!$omp declare target enter(implicitly_captured_with_dev_type_recursive) device_type(host)
+   integer :: increment, k
+   if (increment == 10) then
+      k = increment
+   else
+      k = implicitly_captured_with_dev_type_recursive(increment + 1)
+   end if
+end function implicitly_captured_with_dev_type_recursive
+
+! DEVICE-LABEL: func.func @_QPtarget_function_with_dev_type_recurse
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_with_dev_type_recurse() result(i)
+!$omp declare target enter(target_function_with_dev_type_recurse) device_type(nohost)
+   integer :: i
+   i = implicitly_captured_with_dev_type_recursive(0)
+end function target_function_with_dev_type_recurse
+
+!! -----
+
+module test_module
+contains
+! CHECK-LABEL: func.func @_QMtest_modulePimplicitly_captured_nest_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+   function implicitly_captured_nest_twice() result(i)
+      integer :: i
+      i = 10
+   end function implicitly_captured_nest_twice
+
+! CHECK-LABEL: func.func @_QMtest_modulePimplicitly_captured_one_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+   function implicitly_captured_one_twice() result(k)
+      !$omp declare target enter(implicitly_captured_one_twice) device_type(host)
+      k = implicitly_captured_nest_twice()
+   end function implicitly_captured_one_twice
+
+! DEVICE-LABEL: func.func @_QMtest_modulePimplicitly_captured_two_twice
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+   function implicitly_captured_two_twice() result(y)
+      integer :: y
+      y = 5
+   end function implicitly_captured_two_twice
+
+! DEVICE-LABEL: func.func @_QMtest_modulePtarget_function_test_device
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+   function target_function_test_device() result(j)
+      !$omp declare target enter(target_function_test_device) device_type(nohost)
+      integer :: i, j
+      i = implicitly_captured_one_twice()
+      j = implicitly_captured_two_twice() + i
+   end function target_function_test_device
+end module test_module
+
+!! -----
+
+program mb
+   interface
+      subroutine caller_recursive
+         !$omp declare target enter(caller_recursive) device_type(nohost)
+      end subroutine
+
+      recursive subroutine implicitly_captured_recursive(increment)
+         integer :: increment
+      end subroutine
+   end interface
+end program
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_recursive
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+recursive subroutine implicitly_captured_recursive(increment)
+   integer :: increment
+   if (increment == 10) then
+      return
+   else
+      call implicitly_captured_recursive(increment + 1)
+   end if
+end subroutine
+
+! DEVICE-LABEL: func.func @_QPcaller_recursive
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+subroutine caller_recursive
+!$omp declare target enter(caller_recursive) device_type(nohost)
+   call implicitly_captured_recursive(0)
+end subroutine

flang/test/Lower/OpenMP/declare-target-data.f90

@@ -32,6 +32,10 @@ INTEGER, POINTER :: pt2 => pt2_tar
 INTEGER :: data_int_to = 5
 !$omp declare target to(data_int_to)
 
+!CHECK-DAG: fir.global @_QMtest_0Edata_int_enter {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : i32
+INTEGER :: data_int_enter = 5
+!$omp declare target enter(data_int_enter)
+
 !CHECK-DAG: fir.global @_QMtest_0Edata_int_clauseless {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>} : i32
 INTEGER :: data_int_clauseless = 1
 !$omp declare target(data_int_clauseless)
@@ -42,6 +46,12 @@ REAL :: data_extended_to_1 = 2
 REAL :: data_extended_to_2 = 3
 !$omp declare target to(data_extended_to_1, data_extended_to_2)
 
+!CHECK-DAG: fir.global @_QMtest_0Edata_extended_enter_1 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : f32
+!CHECK-DAG: fir.global @_QMtest_0Edata_extended_enter_2 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : f32
+REAL :: data_extended_enter_1 = 2
+REAL :: data_extended_enter_2 = 3
+!$omp declare target enter(data_extended_enter_1, data_extended_enter_2)
+
 !CHECK-DAG: fir.global @_QMtest_0Edata_extended_link_1 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (link)>} : f32
 !CHECK-DAG: fir.global @_QMtest_0Edata_extended_link_2 {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (link)>} : f32
 REAL :: data_extended_link_1 = 2
@@ -69,4 +79,10 @@ PROGRAM commons
     REAL :: two_to = 2
     COMMON /numbers_to/ one_to, two_to
     !$omp declare target to(/numbers_to/)
+
+    !CHECK-DAG: fir.global @numbers_enter_ {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>} : tuple<f32, f32> {
+    REAL :: one_enter = 1
+    REAL :: two_enter = 2
+    COMMON /numbers_enter/ one_enter, two_enter
+    !$omp declare target enter(/numbers_enter/)
 END

flang/test/Lower/OpenMP/declare-target-func-and-subr.f90

@@ -13,6 +13,14 @@ FUNCTION FUNC_T_DEVICE() RESULT(I)
     I = 1
 END FUNCTION FUNC_T_DEVICE
 
+! DEVICE-LABEL: func.func @_QPfunc_enter_device()
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_ENTER_DEVICE() RESULT(I)
+!$omp declare target enter(FUNC_ENTER_DEVICE) device_type(nohost)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_ENTER_DEVICE
+
 ! HOST-LABEL: func.func @_QPfunc_t_host()
 ! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_T_HOST() RESULT(I)
@@ -21,6 +29,14 @@ FUNCTION FUNC_T_HOST() RESULT(I)
     I = 1
 END FUNCTION FUNC_T_HOST
 
+! HOST-LABEL: func.func @_QPfunc_enter_host()
+! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_ENTER_HOST() RESULT(I)
+!$omp declare target enter(FUNC_ENTER_HOST) device_type(host)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_ENTER_HOST
+
 ! ALL-LABEL: func.func @_QPfunc_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_T_ANY() RESULT(I)
@@ -29,6 +45,14 @@ FUNCTION FUNC_T_ANY() RESULT(I)
     I = 1
 END FUNCTION FUNC_T_ANY
 
+! ALL-LABEL: func.func @_QPfunc_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_ENTER_ANY() RESULT(I)
+!$omp declare target enter(FUNC_ENTER_ANY) device_type(any)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_ENTER_ANY
+
 ! ALL-LABEL: func.func @_QPfunc_default_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_DEFAULT_T_ANY() RESULT(I)
@@ -37,6 +61,14 @@ FUNCTION FUNC_DEFAULT_T_ANY() RESULT(I)
     I = 1
 END FUNCTION FUNC_DEFAULT_T_ANY
 
+! ALL-LABEL: func.func @_QPfunc_default_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+FUNCTION FUNC_DEFAULT_ENTER_ANY() RESULT(I)
+!$omp declare target enter(FUNC_DEFAULT_ENTER_ANY)
+    INTEGER :: I
+    I = 1
+END FUNCTION FUNC_DEFAULT_ENTER_ANY
+
 ! ALL-LABEL: func.func @_QPfunc_default_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 FUNCTION FUNC_DEFAULT_ANY() RESULT(I)
@@ -65,24 +97,48 @@ SUBROUTINE SUBR_T_DEVICE()
 !$omp declare target to(SUBR_T_DEVICE) device_type(nohost)
 END
 
+! DEVICE-LABEL: func.func @_QPsubr_enter_device()
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_ENTER_DEVICE()
+!$omp declare target enter(SUBR_ENTER_DEVICE) device_type(nohost)
+END
+
 ! HOST-LABEL: func.func @_QPsubr_t_host()
 ! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_T_HOST()
 !$omp declare target to(SUBR_T_HOST) device_type(host)
 END
 
+! HOST-LABEL: func.func @_QPsubr_enter_host()
+! HOST-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_ENTER_HOST()
+!$omp declare target enter(SUBR_ENTER_HOST) device_type(host)
+END
+
 ! ALL-LABEL: func.func @_QPsubr_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_T_ANY()
 !$omp declare target to(SUBR_T_ANY) device_type(any)
 END
 
+! ALL-LABEL: func.func @_QPsubr_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_ENTER_ANY()
+!$omp declare target enter(SUBR_ENTER_ANY) device_type(any)
+END
+
 ! ALL-LABEL: func.func @_QPsubr_default_t_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_DEFAULT_T_ANY()
 !$omp declare target to(SUBR_DEFAULT_T_ANY)
 END
 
+! ALL-LABEL: func.func @_QPsubr_default_enter_any()
+! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}
+SUBROUTINE SUBR_DEFAULT_ENTER_ANY()
+!$omp declare target enter(SUBR_DEFAULT_ENTER_ANY)
+END
+
 ! ALL-LABEL: func.func @_QPsubr_default_any()
 ! ALL-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (to)>{{.*}}
 SUBROUTINE SUBR_DEFAULT_ANY()
@@ -108,3 +164,15 @@ RECURSIVE FUNCTION RECURSIVE_DECLARE_TARGET(INCREMENT) RESULT(K)
         K = RECURSIVE_DECLARE_TARGET(INCREMENT + 1)
     END IF
 END FUNCTION RECURSIVE_DECLARE_TARGET
+
+! DEVICE-LABEL: func.func @_QPrecursive_declare_target_enter
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}
+RECURSIVE FUNCTION RECURSIVE_DECLARE_TARGET_ENTER(INCREMENT) RESULT(K)
+!$omp declare target enter(RECURSIVE_DECLARE_TARGET_ENTER) device_type(nohost)
+    INTEGER :: INCREMENT, K
+    IF (INCREMENT == 10) THEN
+        K = INCREMENT
+    ELSE
+        K = RECURSIVE_DECLARE_TARGET_ENTER(INCREMENT + 1)
+    END IF
+END FUNCTION RECURSIVE_DECLARE_TARGET_ENTER

flang/test/Lower/OpenMP/declare-target-implicit-func-and-subr-cap-enter.f90

@@ -0,0 +1,192 @@
+!RUN: %flang_fc1 -emit-hlfir -fopenmp %s -o - | FileCheck %s
+!RUN: %flang_fc1 -emit-hlfir -fopenmp -fopenmp-is-target-device %s -o - | FileCheck %s  --check-prefix=DEVICE
+!RUN: bbc -emit-hlfir -fopenmp %s -o - | FileCheck %s
+!RUN: bbc -emit-hlfir -fopenmp -fopenmp-is-target-device %s -o - | FileCheck %s --check-prefix=DEVICE
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_twice() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_twice
+
+! CHECK-LABEL: func.func @_QPtarget_function_twice_host
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}}
+function target_function_twice_host() result(i)
+!$omp declare target enter(target_function_twice_host) device_type(host)
+   integer :: i
+   i = implicitly_captured_twice()
+end function target_function_twice_host
+
+! DEVICE-LABEL: func.func @_QPtarget_function_twice_device
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_twice_device() result(i)
+!$omp declare target enter(target_function_twice_device) device_type(nohost)
+   integer :: i
+   i = implicitly_captured_twice()
+end function target_function_twice_device
+
+!! -----
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_nest
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_nest() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_nest
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_one
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter){{.*}}}
+function implicitly_captured_one() result(k)
+   k = implicitly_captured_nest()
+end function implicitly_captured_one
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_two
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_two() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_two
+
+! DEVICE-LABEL: func.func @_QPtarget_function_test
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_test() result(j)
+!$omp declare target enter(target_function_test) device_type(nohost)
+   integer :: i, j
+   i = implicitly_captured_one()
+   j = implicitly_captured_two() + i
+end function target_function_test
+
+!! -----
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_nest_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_nest_twice() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_nest_twice
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_one_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_one_twice() result(k)
+   k = implicitly_captured_nest_twice()
+end function implicitly_captured_one_twice
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_two_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_two_twice() result(k)
+   integer :: i
+   i = 10
+   k = i
+end function implicitly_captured_two_twice
+
+! DEVICE-LABEL: func.func @_QPtarget_function_test_device
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_test_device() result(j)
+   !$omp declare target enter(target_function_test_device) device_type(nohost)
+   integer :: i, j
+   i = implicitly_captured_one_twice()
+   j = implicitly_captured_two_twice() + i
+end function target_function_test_device
+
+! CHECK-LABEL: func.func @_QPtarget_function_test_host
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}}
+function target_function_test_host() result(j)
+   !$omp declare target enter(target_function_test_host) device_type(host)
+   integer :: i, j
+   i = implicitly_captured_one_twice()
+   j = implicitly_captured_two_twice() + i
+end function target_function_test_host
+
+!! -----
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_with_dev_type_recursive
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+recursive function implicitly_captured_with_dev_type_recursive(increment) result(k)
+!$omp declare target enter(implicitly_captured_with_dev_type_recursive) device_type(host)
+   integer :: increment, k
+   if (increment == 10) then
+      k = increment
+   else
+      k = implicitly_captured_with_dev_type_recursive(increment + 1)
+   end if
+end function implicitly_captured_with_dev_type_recursive
+
+! DEVICE-LABEL: func.func @_QPtarget_function_with_dev_type_recurse
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+function target_function_with_dev_type_recurse() result(i)
+!$omp declare target enter(target_function_with_dev_type_recurse) device_type(nohost)
+   integer :: i
+   i = implicitly_captured_with_dev_type_recursive(0)
+end function target_function_with_dev_type_recurse
+
+!! -----
+
+module test_module
+contains
+! CHECK-LABEL: func.func @_QMtest_modulePimplicitly_captured_nest_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+   function implicitly_captured_nest_twice() result(i)
+      integer :: i
+      i = 10
+   end function implicitly_captured_nest_twice
+
+! CHECK-LABEL: func.func @_QMtest_modulePimplicitly_captured_one_twice
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (any), capture_clause = (enter)>{{.*}}}
+   function implicitly_captured_one_twice() result(k)
+      !$omp declare target enter(implicitly_captured_one_twice) device_type(host)
+      k = implicitly_captured_nest_twice()
+   end function implicitly_captured_one_twice
+
+! DEVICE-LABEL: func.func @_QMtest_modulePimplicitly_captured_two_twice
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+   function implicitly_captured_two_twice() result(y)
+      integer :: y
+      y = 5
+   end function implicitly_captured_two_twice
+
+! DEVICE-LABEL: func.func @_QMtest_modulePtarget_function_test_device
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+   function target_function_test_device() result(j)
+      !$omp declare target enter(target_function_test_device) device_type(nohost)
+      integer :: i, j
+      i = implicitly_captured_one_twice()
+      j = implicitly_captured_two_twice() + i
+   end function target_function_test_device
+end module test_module
+
+!! -----
+
+program mb
+   interface
+      subroutine caller_recursive
+         !$omp declare target enter(caller_recursive) device_type(nohost)
+      end subroutine
+
+      recursive subroutine implicitly_captured_recursive(increment)
+         integer :: increment
+      end subroutine
+   end interface
+end program
+
+! DEVICE-LABEL: func.func @_QPimplicitly_captured_recursive
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+recursive subroutine implicitly_captured_recursive(increment)
+   integer :: increment
+   if (increment == 10) then
+      return
+   else
+      call implicitly_captured_recursive(increment + 1)
+   end if
+end subroutine
+
+! DEVICE-LABEL: func.func @_QPcaller_recursive
+! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>{{.*}}}
+subroutine caller_recursive
+!$omp declare target enter(caller_recursive) device_type(nohost)
+   call implicitly_captured_recursive(0)
+end subroutine

flang/test/Lower/OpenMP/declare-target-implicit-tarop-cap.f90

@@ -34,6 +34,20 @@ function implicitly_captured_one_twice() result(k)
    k = implicitly_captured_nest_twice()
 end function implicitly_captured_one_twice
 
+! CHECK-LABEL: func.func @_QPimplicitly_captured_nest_twice_enter
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_nest_twice_enter() result(i)
+   integer :: i
+   i = 10
+end function implicitly_captured_nest_twice_enter
+
+! CHECK-LABEL: func.func @_QPimplicitly_captured_one_twice_enter
+! CHECK-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (host), capture_clause = (enter)>{{.*}}}
+function implicitly_captured_one_twice_enter() result(k)
+!$omp declare target enter(implicitly_captured_one_twice_enter) device_type(host)
+   k = implicitly_captured_nest_twice_enter()
+end function implicitly_captured_one_twice_enter
+
 ! DEVICE-LABEL: func.func @_QPimplicitly_captured_two_twice
 ! DEVICE-SAME: {{.*}}attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (to)>{{.*}}}
 function implicitly_captured_two_twice() result(y)

flang/test/Lower/OpenMP/function-filtering-2.f90

@@ -19,6 +19,14 @@ subroutine declaretarget()
     call implicit_invocation()
 end subroutine declaretarget
 
+! MLIR: func.func @{{.*}}declaretarget_enter() attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (enter)>}
+! MLIR: return
+! LLVM: define {{.*}} @{{.*}}declaretarget_enter{{.*}}(
+subroutine declaretarget_enter()
+!$omp declare target enter(declaretarget_enter) device_type(nohost)
+    call implicit_invocation()
+end subroutine declaretarget_enter
+
 ! MLIR: func.func @{{.*}}no_declaretarget() attributes {omp.declare_target = #omp.declaretarget<device_type = (nohost), capture_clause = (to)>}
 ! MLIR: return
 ! LLVM: define {{.*}} @{{.*}}no_declaretarget{{.*}}(

flang/test/Lower/OpenMP/function-filtering.f90

@@ -19,6 +19,16 @@ function device_fn() result(x)
   x = 10
 end function device_fn
 
+! MLIR-ALL: func.func @{{.*}}device_fn_enter(
+! MLIR-ALL: return
+
+! LLVM-ALL: define {{.*}} @{{.*}}device_fn_enter{{.*}}(
+function device_fn_enter() result(x)
+  !$omp declare target enter(device_fn_enter) device_type(nohost)
+  integer :: x
+  x = 10
+end function device_fn_enter
+
 ! MLIR-HOST: func.func @{{.*}}host_fn(
 ! MLIR-HOST: return
 ! MLIR-DEVICE-NOT: func.func {{.*}}host_fn(
@@ -31,6 +41,14 @@ function host_fn() result(x)
   x = 10
 end function host_fn
 
+! LLVM-HOST: define {{.*}} @{{.*}}host_fn_enter{{.*}}(
+! LLVM-DEVICE-NOT: {{.*}} @{{.*}}host_fn_enter{{.*}}(
+function host_fn_enter() result(x)
+  !$omp declare target enter(host_fn_enter) device_type(host)
+  integer :: x
+  x = 10
+end function host_fn_enter
+
 ! MLIR-ALL: func.func @{{.*}}target_subr(
 ! MLIR-ALL: return
 

flang/test/Parser/OpenMP/declare_target-device_type.f90

@@ -2,12 +2,27 @@
 ! RUN: %flang_fc1 -fdebug-dump-parse-tree -fopenmp %s | FileCheck --check-prefix="PARSE-TREE" %s
 
 subroutine openmp_declare_target
-    !CHECK: !$omp declare target device_type(host)
-    !$omp declare target device_type(host)
-    !CHECK: !$omp declare target device_type(nohost)
-    !$omp declare target device_type(nohost)
-    !CHECK: !$omp declare target device_type(any)
-    !$omp declare target device_type(any)
+    integer, save :: x, y
+    !CHECK: !$omp declare target device_type(host) enter(x)
+    !$omp declare target device_type(host) enter(x)
+    !CHECK: !$omp declare target device_type(nohost) enter(x)
+    !$omp declare target device_type(nohost) enter(x)
+    !CHECK: !$omp declare target device_type(any) enter(x)
+    !$omp declare target device_type(any) enter(x)
+
+    !CHECK: !$omp declare target device_type(host) to(x)
+    !$omp declare target device_type(host) to(x)
+    !CHECK: !$omp declare target device_type(nohost) to(x)
+    !$omp declare target device_type(nohost) to(x)
+    !CHECK: !$omp declare target device_type(any) to(x)
+    !$omp declare target device_type(any) to(x)
+
+    !CHECK: !$omp declare target device_type(host) enter(y) to(x)
+    !$omp declare target device_type(host) enter(y) to(x)
+    !CHECK: !$omp declare target device_type(nohost) enter(y) to(x)
+    !$omp declare target device_type(nohost) enter(y) to(x)
+    !CHECK: !$omp declare target device_type(any) enter(y) to(x)
+    !$omp declare target device_type(any) enter(y) to(x)
     integer :: a(1024), i
     !CHECK: do
     do i = 1, 1024

flang/test/Semantics/OpenMP/declarative-directive.f90

@@ -61,12 +61,22 @@ contains
     !WARNING: The entity with PARAMETER attribute is used in a DECLARE TARGET directive
     !WARNING: The entity with PARAMETER attribute is used in a DECLARE TARGET directive
     !$omp declare target (foo, N, M)
+    !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
     !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
     !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
     !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
     !$omp declare target to(Q, S) link(R)
+    !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
+    !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
+    !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
+    !$omp declare target enter(Q, S) link(R)
+    !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
+    !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
     !ERROR: MAP clause is not allowed on the DECLARE TARGET directive
-    !$omp declare target map(from:Q)
+    !$omp declare target to(Q) map(from:Q)
+    !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
+    !ERROR: MAP clause is not allowed on the DECLARE TARGET directive
+    !$omp declare target enter(Q) map(from:Q)
     integer, parameter :: N=10000, M=1024
     integer :: i
     real :: Q(N, N), R(N,M), S(M,M)

flang/test/Semantics/OpenMP/declare-target01.f90

@@ -49,41 +49,89 @@ module declare_target01
   !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
   !$omp declare target (y%KIND)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (my_var)
 
+  !$omp declare target enter (my_var)
+
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (my_var) device_type(host)
+  
+  !$omp declare target enter (my_var) device_type(host)
 
   !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (my_var%t_i)
 
   !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (my_var%t_i)
+
+  !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (my_var%t_arr)
 
+  !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (my_var%t_arr)
+
   !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (my_var%kind_param)
 
   !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (my_var%kind_param)
+
+  !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (my_var%len_param)
 
+  !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (my_var%len_param)
+
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (arr)
 
+  !$omp declare target enter (arr)
+
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (arr) device_type(nohost)
 
+  !$omp declare target enter (arr) device_type(nohost)
+
   !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (arr(1))
 
   !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (arr(1))
+
+  !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (arr(1:2))
 
+  !ERROR: A variable that is part of another variable (as an array or structure element) cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (arr(1:2))
+
   !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (x%KIND)
 
   !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (x%KIND)
+
+  !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (w%LEN)
 
   !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (w%LEN)
+
+  !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (y%KIND)
 
+  !ERROR: A type parameter inquiry cannot appear on the DECLARE TARGET directive
+  !$omp declare target enter (y%KIND)
+
   !$omp declare target link (my_var2)
 
   !$omp declare target link (my_var2) device_type(any)

flang/test/Semantics/OpenMP/declare-target02.f90

@@ -16,13 +16,23 @@ program declare_target02
   !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
   !$omp declare target (a1)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (arr1_to)
 
+  !$omp declare target enter (arr1_to)
+
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (blk1_to)
 
+  !$omp declare target enter (blk1_to)
+
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
   !$omp declare target to (a1_to)
 
+  !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
+  !$omp declare target enter (a1_to)
+
   !$omp declare target link (arr1_link)
 
   !$omp declare target link (blk1_link)
@@ -34,18 +44,26 @@ program declare_target02
   !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
   !$omp declare target (eq_a)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
   !$omp declare target to (eq_a)
 
+  !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
+  !$omp declare target enter (eq_a)
+
   !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
   !$omp declare target link (eq_b)
 
   !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
   !$omp declare target (eq_c)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
   !$omp declare target to (eq_c)
 
+  !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
+  !$omp declare target enter (eq_c)
+
   !ERROR: A variable in a DECLARE TARGET directive cannot appear in an EQUIVALENCE statement
   !$omp declare target link (eq_d)
   equivalence(eq_c, eq_d)
@@ -69,17 +87,32 @@ contains
     !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
     !$omp declare target (a3)
 
+    !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
     !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
     !$omp declare target to (arr2_to)
 
+    !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
+    !$omp declare target enter (arr2_to)
+
+    !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
     !$omp declare target to (arr3_to)
 
+    !$omp declare target enter (arr3_to)
+
+    !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
     !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
     !$omp declare target to (a2_to)
 
+    !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
+    !$omp declare target enter (a2_to)
+
+    !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
     !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
     !$omp declare target to (a3_to)
 
+    !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
+    !$omp declare target enter (a3_to)
+
     !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
     !$omp declare target link (arr2_link)
 
@@ -104,13 +137,22 @@ module mod4
   !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
   !$omp declare target (a4)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to (arr4_to)
 
-  !$omp declare target to (blk4_to)
+  !$omp declare target enter (arr4_to)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
+  !$omp declare target to (blk4_to)
+  !$omp declare target enter (blk4_to)
+
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
   !$omp declare target to (a4_to)
 
+  !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
+  !$omp declare target enter (a4_to)
+
   !$omp declare target link (arr4_link)
 
   !$omp declare target link (blk4_link)
@@ -132,15 +174,27 @@ subroutine func5()
   !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
   !$omp declare target (a5)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
   !$omp declare target to (arr5_to)
+  
+  !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
+  !$omp declare target enter (arr5_to)
 
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
   !$omp declare target to (blk5_to)
 
+  !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
+  !$omp declare target enter (blk5_to)
+
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
   !$omp declare target to (a5_to)
 
+  !ERROR: A variable in a DECLARE TARGET directive cannot be an element of a common block
+  !$omp declare target enter (a5_to)
+
   !ERROR: A variable that appears in a DECLARE TARGET directive must be declared in the scope of a module or have the SAVE attribute, either explicitly or implicitly
   !$omp declare target link (arr5_link)
 

flang/test/Semantics/OpenMP/declare-target06.f90

@@ -15,9 +15,14 @@ module test_0
 !$omp declare target link(no_implicit_materialization_2)
 
 !ERROR: The given DECLARE TARGET directive clause has an invalid argument
+!WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
 !ERROR: No explicit type declared for 'no_implicit_materialization_3'
 !$omp declare target to(no_implicit_materialization_3)
 
+!ERROR: The given DECLARE TARGET directive clause has an invalid argument
+!ERROR: No explicit type declared for 'no_implicit_materialization_3'
+!$omp declare target enter(no_implicit_materialization_3)
+
 INTEGER :: data_int = 10
 !$omp declare target(data_int)
 end module test_0

flang/test/Semantics/OpenMP/requires04.f90

@@ -5,7 +5,10 @@
 ! device constructs, such as declare target with device_type=nohost|any.
 
 subroutine f
-  !$omp declare target device_type(nohost)
+  integer, save :: x
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
+  !$omp declare target to(x) device_type(nohost)
+  !$omp declare target enter(x) device_type(nohost)
 end subroutine f
 
 subroutine g

flang/test/Semantics/OpenMP/requires05.f90

@@ -5,7 +5,9 @@
 ! device constructs, such as declare target with 'to' clause and no device_type.
 
 subroutine f
+  !WARNING: The usage of TO clause on DECLARE TARGET directive has been deprecated. Use ENTER clause instead.
   !$omp declare target to(f)
+  !$omp declare target enter(f)
 end subroutine f
 
 subroutine g

llvm/include/llvm/Frontend/OpenMP/OMP.td

@@ -289,6 +289,9 @@ def OMPC_To : Clause<"to"> {
   let clangClass = "OMPToClause";
   let flangClass = "OmpObjectList";
 }
+def OMPC_Enter : Clause<"enter"> {
+  let flangClass = "OmpObjectList";
+}
 def OMPC_From : Clause<"from"> {
   let clangClass = "OMPFromClause";
   let flangClass = "OmpObjectList";
@@ -1124,7 +1127,8 @@ def OMP_DeclareTarget : Directive<"declare target"> {
   let allowedClauses = [
     VersionedClause<OMPC_To>,
     VersionedClause<OMPC_Link>,
-    VersionedClause<OMPC_Indirect>
+    VersionedClause<OMPC_Indirect>,
+    VersionedClause<OMPC_Enter, 52>
   ];
   let allowedOnceClauses = [
     VersionedClause<OMPC_DeviceType, 50>