[OPENMP] Add 'reverse_offload' clause to OMP5.0 'requires' directive

[patricklyster]

Summary

Added new reverse_offload clause to existing OMP5.0 requires directive

[ABataev]

LG

clang/include/clang/AST/OpenMPClause.h

child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
 
   static bool classof(const OMPClause *T) {
     return T->getClauseKind() == OMPC_unified_shared_memory;
   }
 };
 
+/// This represents 'reverse_offload' clause in the '#pragma omp requires'
+/// directive.
+///
+/// \code
+/// #pragma omp requires reverse_offload
+/// \endcode
+/// In this example directive '#pragma omp requires' has 'reverse_offload'
+/// clause.
+class OMPReverseOffloadClause final : public OMPClause {
+public:
+  friend class OMPClauseReader;
+  /// Build 'reverse_offload' clause.
+  ///
+  /// \param StartLoc Starting location of the clause.
+  /// \param EndLoc Ending location of the clause.
+  OMPReverseOffloadClause(SourceLocation StartLoc, SourceLocation EndLoc)
+      : OMPClause(OMPC_reverse_offload, StartLoc, EndLoc) {}
+
+  /// Build an empty clause.
+  OMPReverseOffloadClause()
+      : OMPClause(OMPC_reverse_offload, SourceLocation(), SourceLocation()) {}
+
+  child_range children() {
+    return child_range(child_iterator(), child_iterator());
+  }
+
+  static bool classof(const OMPClause *T) {
+    return T->getClauseKind() == OMPC_reverse_offload;
+  }
+};
+
 /// This represents 'schedule' clause in the '#pragma omp ...' directive.
 ///
 /// \code
 /// #pragma omp for schedule(static, 3)
 /// \endcode
 /// In this example directive '#pragma omp for' has 'schedule' clause with
 /// arguments 'static' and '3'.
 class OMPScheduleClause : public OMPClause, public OMPClauseWithPreInit {

clang/include/clang/AST/RecursiveASTVisitor.h

 
 template <typename Derived>
 bool RecursiveASTVisitor<Derived>::VisitOMPUnifiedSharedMemoryClause(
     OMPUnifiedSharedMemoryClause *) {
   return true;
 }
 
 template <typename Derived>
+bool RecursiveASTVisitor<Derived>::VisitOMPReverseOffloadClause(
+    OMPReverseOffloadClause *) {
+  return true;
+}
+
+template <typename Derived>
 bool
 RecursiveASTVisitor<Derived>::VisitOMPScheduleClause(OMPScheduleClause *C) {
   TRY_TO(VisitOMPClauseWithPreInit(C));
   TRY_TO(TraverseStmt(C->getChunkSize()));
   return true;
 }
 
 template <typename Derived>

clang/include/clang/Basic/OpenMPKinds.def

 OPENMP_CLAUSE(to, OMPToClause)
 OPENMP_CLAUSE(from, OMPFromClause)
 OPENMP_CLAUSE(use_device_ptr, OMPUseDevicePtrClause)
 OPENMP_CLAUSE(is_device_ptr, OMPIsDevicePtrClause)
 OPENMP_CLAUSE(task_reduction,  OMPTaskReductionClause)
 OPENMP_CLAUSE(in_reduction,  OMPInReductionClause)
 OPENMP_CLAUSE(unified_address, OMPUnifiedAddressClause)
 OPENMP_CLAUSE(unified_shared_memory, OMPUnifiedSharedMemoryClause)
+OPENMP_CLAUSE(reverse_offload, OMPReverseOffloadClause)
 
 // Clauses allowed for OpenMP directive 'parallel'.
 OPENMP_PARALLEL_CLAUSE(if)
 OPENMP_PARALLEL_CLAUSE(num_threads)
 OPENMP_PARALLEL_CLAUSE(default)
 OPENMP_PARALLEL_CLAUSE(proc_bind)
 OPENMP_PARALLEL_CLAUSE(private)
 OPENMP_PARALLEL_CLAUSE(firstprivate)

 OPENMP_TARGET_CLAUSE(defaultmap)
 OPENMP_TARGET_CLAUSE(firstprivate)
 OPENMP_TARGET_CLAUSE(is_device_ptr)
 OPENMP_TARGET_CLAUSE(reduction)
 
 // Clauses allowed for OpenMP directive 'requires'.
 OPENMP_REQUIRES_CLAUSE(unified_address)
 OPENMP_REQUIRES_CLAUSE(unified_shared_memory)
+OPENMP_REQUIRES_CLAUSE(reverse_offload)
 
 // Clauses allowed for OpenMP directive 'target data'.
 OPENMP_TARGET_DATA_CLAUSE(if)
 OPENMP_TARGET_DATA_CLAUSE(device)
 OPENMP_TARGET_DATA_CLAUSE(map)
 OPENMP_TARGET_DATA_CLAUSE(use_device_ptr)
 
 // Clauses allowed for OpenMP directive 'target enter data'.

clang/include/clang/Sema/Sema.h

OMPClause *ActOnOpenMPNogroupClause(SourceLocation StartLoc,
                                       SourceLocation EndLoc);
   /// Called on well-formed 'unified_address' clause.
   OMPClause *ActOnOpenMPUnifiedAddressClause(SourceLocation StartLoc,
                                              SourceLocation EndLoc);
 
   /// Called on well-formed 'unified_address' clause.
   OMPClause *ActOnOpenMPUnifiedSharedMemoryClause(SourceLocation StartLoc,
                                                   SourceLocation EndLoc);
   
+  /// Called on well-formed 'reverse_offload' clause.
+  OMPClause *ActOnOpenMPReverseOffloadClause(SourceLocation StartLoc,
+                                             SourceLocation EndLoc);
+
   OMPClause *ActOnOpenMPVarListClause(
       OpenMPClauseKind Kind, ArrayRef<Expr *> Vars, Expr *TailExpr,
       SourceLocation StartLoc, SourceLocation LParenLoc,
       SourceLocation ColonLoc, SourceLocation EndLoc,
       CXXScopeSpec &ReductionIdScopeSpec,
       const DeclarationNameInfo &ReductionId, OpenMPDependClauseKind DepKind,
       OpenMPLinearClauseKind LinKind, OpenMPMapClauseKind MapTypeModifier,
       OpenMPMapClauseKind MapType, bool IsMapTypeImplicit,

clang/lib/AST/OpenMPClause.cpp

const OMPClauseWithPreInit *OMPClauseWithPreInit::get(const OMPClause *C) {
   case OMPC_unknown:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     break;
   }
 
   return nullptr;
 }
 
 OMPClauseWithPostUpdate *OMPClauseWithPostUpdate::get(OMPClause *C) {
   auto *Res = OMPClauseWithPostUpdate::get(const_cast<const OMPClause *>(C));
const OMPClauseWithPostUpdate *OMPClauseWithPostUpdate::get(const OMPClause *C) {
   case OMPC_unknown:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     break;
   }
 
   return nullptr;
 }
 
 OMPOrderedClause *OMPOrderedClause::Create(const ASTContext &C, Expr *Num,
                                            unsigned NumLoops,

clang/lib/AST/StmtPrinter.cpp

void OMPClausePrinter::VisitOMPUnifiedAddressClause(OMPUnifiedAddressClause *) {
   OS << "unified_address";
 }
 
 void OMPClausePrinter::VisitOMPUnifiedSharedMemoryClause(
     OMPUnifiedSharedMemoryClause *) {
   OS << "unified_shared_memory";
 }
 
+void OMPClausePrinter::VisitOMPReverseOffloadClause(OMPReverseOffloadClause *) {
+  OS << "reverse_offload";
+}
+
 void OMPClausePrinter::VisitOMPScheduleClause(OMPScheduleClause *Node) {
   OS << "schedule(";
   if (Node->getFirstScheduleModifier() != OMPC_SCHEDULE_MODIFIER_unknown) {
     OS << getOpenMPSimpleClauseTypeName(OMPC_schedule,
                                         Node->getFirstScheduleModifier());
     if (Node->getSecondScheduleModifier() != OMPC_SCHEDULE_MODIFIER_unknown) {
       OS << ", ";
       OS << getOpenMPSimpleClauseTypeName(OMPC_schedule,

clang/lib/AST/StmtProfile.cpp

 void OMPClauseProfiler::VisitOMPProcBindClause(const OMPProcBindClause *C) { }
 
 void OMPClauseProfiler::VisitOMPUnifiedAddressClause(
     const OMPUnifiedAddressClause *C) {}
 
 void OMPClauseProfiler::VisitOMPUnifiedSharedMemoryClause(
     const OMPUnifiedSharedMemoryClause *C) {}
 
+void OMPClauseProfiler::VisitOMPReverseOffloadClause(
+    const OMPReverseOffloadClause *C) {}
+
 void OMPClauseProfiler::VisitOMPScheduleClause(const OMPScheduleClause *C) {
   VistOMPClauseWithPreInit(C);
   if (auto *S = C->getChunkSize())
     Profiler->VisitStmt(S);
 }
 
 void OMPClauseProfiler::VisitOMPOrderedClause(const OMPOrderedClause *C) {
   if (auto *Num = C->getNumForLoops())

clang/lib/Basic/OpenMPKinds.cpp

#include "clang/Basic/OpenMPKinds.def"
   case OMPC_hint:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     break;
   }
   llvm_unreachable("Invalid OpenMP simple clause kind");
 }
 
 const char *clang::getOpenMPSimpleClauseTypeName(OpenMPClauseKind Kind,
                                                  unsigned Type) {
   switch (Kind) {
#include "clang/Basic/OpenMPKinds.def"
   case OMPC_hint:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     break;
   }
   llvm_unreachable("Invalid OpenMP simple clause kind");
 }
 
 bool clang::isAllowedClauseForDirective(OpenMPDirectiveKind DKind,
                                         OpenMPClauseKind CKind) {
   assert(DKind <= OMPD_unknown);

clang/lib/CodeGen/CGStmtOpenMP.cpp

static void emitOMPAtomicExpr(CodeGenFunction &CGF, OpenMPClauseKind Kind,
   case OMPC_defaultmap:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     llvm_unreachable("Clause is not allowed in 'omp atomic'.");
   }
 }
 
 void CodeGenFunction::EmitOMPAtomicDirective(const OMPAtomicDirective &S) {
   bool IsSeqCst = S.getSingleClause<OMPSeqCstClause>();
   OpenMPClauseKind Kind = OMPC_unknown;
   for (const OMPClause *C : S.clauses()) {

clang/lib/Parse/ParseOpenMP.cpp

OMPClause *Parser::ParseOpenMPClause(OpenMPDirectiveKind DKind,
   case OMPC_update:
   case OMPC_capture:
   case OMPC_seq_cst:
   case OMPC_threads:
   case OMPC_simd:
   case OMPC_nogroup:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     // OpenMP [2.7.1, Restrictions, p. 9]
     //  Only one ordered clause can appear on a loop directive.
     // OpenMP [2.7.1, Restrictions, C/C++, p. 4]
     //  Only one nowait clause can appear on a for directive.
     // OpenMP [5.0, Requires directive, Restrictions]
     //   Each of the requires clauses can appear at most once on the directive.
     if (!FirstClause) {
       Diag(Tok, diag::err_omp_more_one_clause)

clang/lib/Sema/SemaOpenMP.cpp

OMPClause *Sema::ActOnOpenMPSingleExprClause(OpenMPClauseKind Kind, Expr *Expr,
   case OMPC_unknown:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
 }
 
 // An OpenMP directive such as 'target parallel' has two captured regions:
 // for the 'target' and 'parallel' respectively.  This function returns
 // the region in which to capture expressions associated with a clause.
static OpenMPDirectiveKind getOpenMPCaptureRegionForClause(
   case OMPC_unknown:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     llvm_unreachable("Unexpected OpenMP clause.");
   }
   return CaptureRegion;
 }
 
 OMPClause *Sema::ActOnOpenMPIfClause(OpenMPDirectiveKind NameModifier,
                                      Expr *Condition, SourceLocation StartLoc,
                                      SourceLocation LParenLoc,
OMPClause *Sema::ActOnOpenMPSimpleClause(
   case OMPC_unknown:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
 }
 
 static std::string
 getListOfPossibleValues(OpenMPClauseKind K, unsigned First, unsigned Last,
                         ArrayRef<unsigned> Exclude = llvm::None) {
OMPClause *Sema::ActOnOpenMPSingleExprWithArgClause(
   case OMPC_unknown:
   case OMPC_uniform:
   case OMPC_to:
   case OMPC_from:
   case OMPC_use_device_ptr:
   case OMPC_is_device_ptr:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
 }
 
 static bool checkScheduleModifiers(Sema &S, OpenMPScheduleClauseModifier M1,
                                    OpenMPScheduleClauseModifier M2,
                                    SourceLocation M1Loc, SourceLocation M2Loc) {
case OMPC_nogroup:
     Res = ActOnOpenMPNogroupClause(StartLoc, EndLoc);
     break;
   case OMPC_unified_address:
     Res = ActOnOpenMPUnifiedAddressClause(StartLoc, EndLoc);
     break;
   case OMPC_unified_shared_memory:
     Res = ActOnOpenMPUnifiedSharedMemoryClause(StartLoc, EndLoc);
     break;
+  case OMPC_reverse_offload:
+    Res = ActOnOpenMPReverseOffloadClause(StartLoc, EndLoc);
+    break;
   case OMPC_if:
   case OMPC_final:
   case OMPC_num_threads:
   case OMPC_safelen:
   case OMPC_simdlen:
   case OMPC_collapse:
   case OMPC_schedule:
   case OMPC_private:
OMPClause *Sema::ActOnOpenMPUnifiedAddressClause(SourceLocation StartLoc,
   return new (Context) OMPUnifiedAddressClause(StartLoc, EndLoc);
 }
 
 OMPClause *Sema::ActOnOpenMPUnifiedSharedMemoryClause(SourceLocation StartLoc,
                                                       SourceLocation EndLoc) {
   return new (Context) OMPUnifiedSharedMemoryClause(StartLoc, EndLoc);
 }
 
+OMPClause *Sema::ActOnOpenMPReverseOffloadClause(SourceLocation StartLoc,
+                                                 SourceLocation EndLoc) {
+  return new (Context) OMPReverseOffloadClause(StartLoc, EndLoc);
+}
+
 OMPClause *Sema::ActOnOpenMPVarListClause(
     OpenMPClauseKind Kind, ArrayRef<Expr *> VarList, Expr *TailExpr,
     SourceLocation StartLoc, SourceLocation LParenLoc, SourceLocation ColonLoc,
     SourceLocation EndLoc, CXXScopeSpec &ReductionIdScopeSpec,
     const DeclarationNameInfo &ReductionId, OpenMPDependClauseKind DepKind,
     OpenMPLinearClauseKind LinKind, OpenMPMapClauseKind MapTypeModifier,
     OpenMPMapClauseKind MapType, bool IsMapTypeImplicit,
     SourceLocation DepLinMapLoc) {
OMPClause *Sema::ActOnOpenMPVarListClause(
   case OMPC_num_tasks:
   case OMPC_hint:
   case OMPC_dist_schedule:
   case OMPC_defaultmap:
   case OMPC_unknown:
   case OMPC_uniform:
   case OMPC_unified_address:
   case OMPC_unified_shared_memory:
+  case OMPC_reverse_offload:
     llvm_unreachable("Clause is not allowed.");
   }
   return Res;
 }
 
 ExprResult Sema::getOpenMPCapturedExpr(VarDecl *Capture, ExprValueKind VK,
                                        ExprObjectKind OK, SourceLocation Loc) {
   ExprResult Res = BuildDeclRefExpr(

clang/lib/Sema/TreeTransform.h

 template <typename Derived>
 OMPClause *TreeTransform<Derived>::TransformOMPUnifiedSharedMemoryClause(
     OMPUnifiedSharedMemoryClause *C) {
   llvm_unreachable(
       "unified_shared_memory clause cannot appear in dependent context");
 }
 
 template <typename Derived>
+OMPClause *TreeTransform<Derived>::TransformOMPReverseOffloadClause(
+    OMPReverseOffloadClause *C) {
+  llvm_unreachable("reverse_offload clause cannot appear in dependent context");
+}
+
+template <typename Derived>
 OMPClause *
 TreeTransform<Derived>::TransformOMPPrivateClause(OMPPrivateClause *C) {
   llvm::SmallVector<Expr *, 16> Vars;
   Vars.reserve(C->varlist_size());
   for (auto *VE : C->varlists()) {
     ExprResult EVar = getDerived().TransformExpr(cast<Expr>(VE));
     if (EVar.isInvalid())
       return nullptr;

clang/lib/Serialization/ASTReader.cpp

case OMPC_nogroup:
     C = new (Context) OMPNogroupClause();
     break;
   case OMPC_unified_address:
     C = new (Context) OMPUnifiedAddressClause();
     break;
   case OMPC_unified_shared_memory:
     C = new (Context) OMPUnifiedSharedMemoryClause();
     break;
+  case OMPC_reverse_offload:
+    C = new (Context) OMPReverseOffloadClause();
+    break;
   case OMPC_private:
     C = OMPPrivateClause::CreateEmpty(Context, Record.readInt());
     break;
   case OMPC_firstprivate:
     C = OMPFirstprivateClause::CreateEmpty(Context, Record.readInt());
     break;
   case OMPC_lastprivate:
     C = OMPLastprivateClause::CreateEmpty(Context, Record.readInt());

 
 void OMPClauseReader::VisitOMPNogroupClause(OMPNogroupClause *) {}
 
 void OMPClauseReader::VisitOMPUnifiedAddressClause(OMPUnifiedAddressClause *) {}
 
 void OMPClauseReader::VisitOMPUnifiedSharedMemoryClause(
     OMPUnifiedSharedMemoryClause *) {}
 
+void OMPClauseReader::VisitOMPReverseOffloadClause(OMPReverseOffloadClause *) {}
+
 void OMPClauseReader::VisitOMPPrivateClause(OMPPrivateClause *C) {
   C->setLParenLoc(Record.readSourceLocation());
   unsigned NumVars = C->varlist_size();
   SmallVector<Expr *, 16> Vars;
   Vars.reserve(NumVars);
   for (unsigned i = 0; i != NumVars; ++i)
     Vars.push_back(Record.readSubExpr());
   C->setVarRefs(Vars);

clang/lib/Serialization/ASTWriter.cpp

for (auto &M : C->all_components()) {
     Record.AddDeclRef(M.getAssociatedDeclaration());
   }
 }
 
 void OMPClauseWriter::VisitOMPUnifiedAddressClause(OMPUnifiedAddressClause *) {}
 
 void OMPClauseWriter::VisitOMPUnifiedSharedMemoryClause(
     OMPUnifiedSharedMemoryClause *) {}
+
+void OMPClauseWriter::VisitOMPReverseOffloadClause(OMPReverseOffloadClause *) {}

clang/test/OpenMP/requires_unified_address_ast_print.cpp

 #define HEADER
 
 #pragma omp requires unified_address 
 // CHECK:#pragma omp requires unified_address
 
 #pragma omp requires unified_shared_memory
 // CHECK:#pragma omp requires unified_shared_memory
 
+#pragma omp requires reverse_offload
+// CHECK:#pragma omp requires reverse_offload
+
 #endif

clang/test/OpenMP/requires_unified_address_messages.cpp

 // RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100  %s
 
 #pragma omp requires unified_address // expected-note {{unified_address clause previously used here}} expected-note {{unified_address clause previously used here}} expected-note {{unified_address clause previously used here}} expected-note {{unified_address clause previously used here}} expected-note {{unified_address clause previously used here}} expected-note{{unified_address clause previously used here}}
 
 #pragma omp requires unified_shared_memory // expected-note {{unified_shared_memory clause previously used here}} expected-note{{unified_shared_memory clause previously used here}}
 
 #pragma omp requires unified_shared_memory, unified_shared_memory // expected-error {{Only one unified_shared_memory clause can appear on a requires directive in a single translation unit}} expected-error {{directive '#pragma omp requires' cannot contain more than one 'unified_shared_memory' clause}}
 
 #pragma omp requires unified_address // expected-error {{Only one unified_address clause can appear on a requires directive in a single translation unit}} 
 
 #pragma omp requires unified_address, unified_address // expected-error {{Only one unified_address clause can appear on a requires directive in a single translation unit}} expected-error {{directive '#pragma omp requires' cannot contain more than one 'unified_address' clause}}
 
+#pragma omp requires reverse_offload // expected-note {{reverse_offload clause previously used here}} expected-note {{reverse_offload clause previously used here}}
+
+#pragma omp requires reverse_offload, reverse_offload // expected-error {{Only one reverse_offload clause can appear on a requires directive in a single translation unit}} expected-error {{directive '#pragma omp requires' cannot contain more than one 'reverse_offload' clause}}
+
 #pragma omp requires // expected-error {{expected at least one clause on '#pragma omp requires' directive}}
 
 #pragma omp requires invalid_clause // expected-warning {{extra tokens at the end of '#pragma omp requires' are ignored}} expected-error {{expected at least one clause on '#pragma omp requires' directive}}
 
 #pragma omp requires nowait // expected-error {{unexpected OpenMP clause 'nowait' in directive '#pragma omp requires'}} expected-error {{expected at least one clause on '#pragma omp requires' directive}}
 
 #pragma omp requires unified_address, invalid_clause // expected-warning {{extra tokens at the end of '#pragma omp requires' are ignored}} expected-error {{Only one unified_address clause can appear on a requires directive in a single translation unit}}
 
 #pragma omp requires invalid_clause unified_address // expected-warning {{extra tokens at the end of '#pragma omp requires' are ignored}} expected-error {{expected at least one clause on '#pragma omp requires' directive}}
 
-#pragma omp requires unified_shared_memory, unified_address // expected-error {{Only one unified_shared_memory clause can appear on a requires directive in a single translation unit}} expected-error{{Only one unified_address clause can appear on a requires directive in a single translation unit}}
+#pragma omp requires unified_shared_memory, unified_address, reverse_offload // expected-error {{Only one unified_shared_memory clause can appear on a requires directive in a single translation unit}} expected-error{{Only one unified_address clause can appear on a requires directive in a single translation unit}} expected-error{{Only one reverse_offload clause can appear on a requires directive in a single translation unit}}
 
 namespace A {
   #pragma omp requires unified_address // expected-error {{Only one unified_address clause can appear on a requires directive in a single translation unit}}
   namespace B {
     #pragma omp requires unified_address // expected-error {{Only one unified_address clause can appear on a requires directive in a single translation unit}}
   }
 }
 

clang/tools/libclang/CIndex.cpp

 void OMPClauseEnqueue::VisitOMPNogroupClause(const OMPNogroupClause *) {}
 
 void OMPClauseEnqueue::VisitOMPUnifiedAddressClause(
     const OMPUnifiedAddressClause *) {}
 
 void OMPClauseEnqueue::VisitOMPUnifiedSharedMemoryClause(
     const OMPUnifiedSharedMemoryClause *) {}
 
+void OMPClauseEnqueue::VisitOMPReverseOffloadClause(
+    const OMPReverseOffloadClause *) {}
+
 void OMPClauseEnqueue::VisitOMPDeviceClause(const OMPDeviceClause *C) {
   Visitor->AddStmt(C->getDevice());
 }
 
 void OMPClauseEnqueue::VisitOMPNumTeamsClause(const OMPNumTeamsClause *C) {
   VisitOMPClauseWithPreInit(C);
   Visitor->AddStmt(C->getNumTeams());
 }