diff --git a/include/llvm/Frontend/Directive/DirectiveBase.td b/include/llvm/Frontend/Directive/DirectiveBase.td
index 26049ca60db..13b1edef058 100644
--- a/include/llvm/Frontend/Directive/DirectiveBase.td
+++ b/include/llvm/Frontend/Directive/DirectiveBase.td
@@ -46,6 +46,9 @@ class DirectiveLanguage {
 
   // EnumSet class name used for clauses to generated the allowed clauses map.
   string clauseEnumSetClass = "";
+
+  // Class holding the clauses in the flang parse-tree.
+  string flangClauseBaseClass = "";
 }
 
 // Information about a specific clause.
@@ -57,10 +60,20 @@ class Clause<string c> {
   string alternativeName = "";
 
   // Optional class holding value of the clause in clang AST.
-  string clangClass = ?;
+  string clangClass = "";
+
+  // Optional class holding the clause in flang AST. If left blank, the class
+  // is assumed to be the name of the clause with capitalized word and
+  // underscores removed.
+  // ex: async -> Async
+  //     num_threads -> NumThreads
+  string flangClass = "";
 
   // Optional class holding value of the clause in flang AST.
-  string flangClass = ?;
+  string flangClassValue = "";
+
+  // If set to 1, value is optional. Not optional by default.
+  bit isValueOptional = 0;
 
   // Is clause implicit? If clause is set as implicit, the default kind will
   // be return in get<LanguageName>ClauseKind instead of their own kind.
diff --git a/include/llvm/Frontend/OpenACC/ACC.td b/include/llvm/Frontend/OpenACC/ACC.td
index 4dbf4bbc0fb..4c686aad050 100644
--- a/include/llvm/Frontend/OpenACC/ACC.td
+++ b/include/llvm/Frontend/OpenACC/ACC.td
@@ -25,28 +25,30 @@ def OpenACC : DirectiveLanguage {
   let enableBitmaskEnumInNamespace = 1;
   let includeHeader = "llvm/Frontend/OpenACC/ACC.h.inc";
   let clauseEnumSetClass = "AccClauseSet";
+  let flangClauseBaseClass = "AccClause";
 }
 
 //===----------------------------------------------------------------------===//
 // Definition of OpenACC clauses
 //===----------------------------------------------------------------------===//
 
+// 2.16.1
+def ACCC_Async : Clause<"async"> {
+  let flangClassValue = "ScalarIntExpr";
+  let isValueOptional = 1;
+}
+
 // 2.9.6
 def ACCC_Auto : Clause<"auto"> {}
 
-// 2.16.1
-def ACCC_Async : Clause<"async"> {
-  let flangClass = "std::optional<ScalarIntExpr>";
-}
-
 // 2.7.11
 def ACCC_Attach : Clause<"attach"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.15.1
 def ACCC_Bind : Clause<"bind"> {
-  let flangClass = "Name";
+  let flangClassValue = "Name";
 }
 
 // 2.12
@@ -55,72 +57,73 @@ def ACCC_Capture : Clause<"capture"> {
 
 // 2.9.1
 def ACCC_Collapse : Clause<"collapse"> {
-  let flangClass = "ScalarIntConstantExpr";
+  let flangClassValue = "ScalarIntConstantExpr";
 }
 
 // 2.7.5
 def ACCC_Copy : Clause<"copy"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 // 2.7.6
 def ACCC_Copyin : Clause<"copyin"> {
-  let flangClass = "AccObjectListWithModifier";
+  let flangClassValue = "AccObjectListWithModifier";
 }
 
 // 2.7.7
 def ACCC_Copyout : Clause<"copyout"> {
-  let flangClass = "AccObjectListWithModifier";
+  let flangClassValue = "AccObjectListWithModifier";
 }
 
 // 2.7.8
 def ACCC_Create : Clause<"create"> {
-  let flangClass = "AccObjectListWithModifier";
+  let flangClassValue = "AccObjectListWithModifier";
 }
 
 // 2.5.14
 def ACCC_Default : Clause<"default"> {
-  let flangClass = "AccDefaultClause";
+  let flangClassValue = "AccDefaultClause";
 }
 
 // 2.4.12
 def ACCC_DefaultAsync : Clause<"default_async"> {
-  let flangClass = "ScalarIntExpr";
+  let flangClassValue = "ScalarIntExpr";
 }
 
 // 2.7.10
 def ACCC_Delete : Clause<"delete"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.7.12
 def ACCC_Detach : Clause<"detach"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.14.4
 def ACCC_Device : Clause<"device"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.14.1
 def ACCC_DeviceNum : Clause<"device_num">  {
-  let flangClass = "ScalarIntConstantExpr";
+  let flangClassValue = "ScalarIntConstantExpr";
 }
 
 // 2.7.3
 def ACCC_DevicePtr : Clause<"deviceptr"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.13
 def ACCC_DeviceResident : Clause<"device_resident"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.4
 def ACCC_DeviceType : Clause<"device_type"> {
   // (DeviceType, "*"
-  let flangClass = "std::optional<std::list<Name>>";
+  let flangClassValue = "std::list<Name>";
+  let isValueOptional = 1;
 }
 
 // 2.6.6
@@ -128,22 +131,23 @@ def ACCC_Finalize : Clause<"finalize"> {}
 
 // 2.5.12
 def ACCC_FirstPrivate : Clause<"firstprivate"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.9.2
 def ACCC_Gang : Clause<"gang"> {
-  let flangClass = "std::optional<AccGangArgument>";
+  let flangClassValue = "AccGangArgument";
+  let isValueOptional = 1;
 }
 
 // 2.14.4
 def ACCC_Host : Clause<"host"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.5.4
 def ACCC_If : Clause <"if"> {
-  let flangClass = "ScalarLogicalExpr";
+  let flangClassValue = "ScalarLogicalExpr";
 }
 
 // 2.14.4
@@ -154,12 +158,12 @@ def ACCC_Independent : Clause<"independent"> {}
 
 // 2.13
 def ACCC_Link : Clause<"link"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.7.9
 def ACCC_NoCreate : Clause<"no_create"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.15.1
@@ -167,32 +171,32 @@ def ACCC_NoHost : Clause<"nohost"> {}
 
 // 2.5.8
 def ACCC_NumGangs : Clause<"num_gangs"> {
-  let flangClass = "ScalarIntExpr";
+  let flangClassValue = "ScalarIntExpr";
 }
 
 // 2.5.9
 def ACCC_NumWorkers : Clause<"num_workers"> {
-  let flangClass = "ScalarIntExpr";
+  let flangClassValue = "ScalarIntExpr";
 }
 
 // 2.7.4
 def ACCC_Present : Clause<"present"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.5.11
 def ACCC_Private : Clause<"private"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.9.7
 def ACCC_Tile : Clause <"tile"> {
-  let flangClass = "AccSizeExprList";
+  let flangClassValue = "AccSizeExprList";
 }
 
 // 2.8.1
 def ACCC_UseDevice : Clause <"use_device"> {
-  let flangClass = "AccObjectList";
+  let flangClassValue = "AccObjectList";
 }
 
 // 2.12
@@ -200,12 +204,13 @@ def ACCC_Read : Clause<"read"> {}
 
 // 2.5.13
 def ACCC_Reduction : Clause<"reduction"> {
-  let flangClass = "AccObjectListWithReduction";
+  let flangClassValue = "AccObjectListWithReduction";
 }
 
 // 2.5.5
 def ACCC_Self : Clause<"self"> {
-  let flangClass = "std::optional<ScalarLogicalExpr>";
+  let flangClassValue = "ScalarLogicalExpr";
+  let isValueOptional = 1;
 }
 
 // 2.9.5
@@ -213,22 +218,25 @@ def ACCC_Seq : Clause<"seq"> {}
 
 // 2.9.4
 def ACCC_Vector : Clause<"vector"> {
-  let flangClass = "std::optional<ScalarIntExpr>";
+  let flangClassValue = "ScalarIntExpr";
+  let isValueOptional = 1;
 }
 
 // 2.5.10
 def ACCC_VectorLength : Clause<"vector_length"> {
-  let flangClass = "ScalarIntExpr";
+  let flangClassValue = "ScalarIntExpr";
 }
 
 // 2.16.2
 def ACCC_Wait : Clause<"wait"> {
-  let flangClass = "std::optional<AccWaitArgument>";
+  let flangClassValue = "AccWaitArgument";
+  let isValueOptional = 1;
 }
 
 // 2.9.3
 def ACCC_Worker: Clause<"worker"> {
-  let flangClass = "std::optional<ScalarIntExpr>";
+  let flangClassValue = "ScalarIntExpr";
+  let isValueOptional = 1;
 }
 
 // 2.12
diff --git a/include/llvm/Frontend/OpenMP/OMP.td b/include/llvm/Frontend/OpenMP/OMP.td
index a0d694533e4..24111c9e470 100644
--- a/include/llvm/Frontend/OpenMP/OMP.td
+++ b/include/llvm/Frontend/OpenMP/OMP.td
@@ -25,6 +25,7 @@ def OpenMP : DirectiveLanguage {
   let enableBitmaskEnumInNamespace = 1;
   let includeHeader = "llvm/Frontend/OpenMP/OMP.h.inc";
   let clauseEnumSetClass = "OmpClauseSet";
+  let flangClauseBaseClass = "OmpClause";
 }
 
 //===----------------------------------------------------------------------===//
@@ -34,38 +35,87 @@ def OpenMP : DirectiveLanguage {
 def OMPC_Allocator : Clause<"allocator"> {
   let clangClass = "OMPAllocatorClause";
 }
-def OMPC_If : Clause<"if"> { let clangClass = "OMPIfClause"; }
-def OMPC_Final : Clause<"final"> { let clangClass = "OMPFinalClause"; }
+def OMPC_If : Clause<"if"> {
+  let clangClass = "OMPIfClause";
+  let flangClass = "OmpIfClause";
+}
+def OMPC_Final : Clause<"final"> {
+  let clangClass = "OMPFinalClause";
+  let flangClassValue = "ScalarLogicalExpr";
+}
 def OMPC_NumThreads : Clause<"num_threads"> {
   let clangClass = "OMPNumThreadsClause";
+  let flangClassValue = "ScalarIntExpr";
+}
+def OMPC_SafeLen : Clause<"safelen"> {
+  let clangClass = "OMPSafelenClause";
+  let flangClassValue = "ScalarIntConstantExpr";
+}
+def OMPC_SimdLen : Clause<"simdlen"> {
+  let clangClass = "OMPSimdlenClause";
+  let flangClassValue = "ScalarIntConstantExpr";
+}
+def OMPC_Collapse : Clause<"collapse"> {
+  let clangClass = "OMPCollapseClause";
+  let flangClassValue = "ScalarIntConstantExpr";
+}
+def OMPC_Default : Clause<"default"> {
+  let clangClass = "OMPDefaultClause";
+  let flangClass = "OmpDefaultClause";
+}
+def OMPC_Private : Clause<"private"> {
+  let clangClass = "OMPPrivateClause";
+  let flangClassValue = "OmpObjectList";
 }
-def OMPC_SafeLen : Clause<"safelen"> { let clangClass = "OMPSafelenClause"; }
-def OMPC_SimdLen : Clause<"simdlen"> { let clangClass = "OMPSimdlenClause"; }
-def OMPC_Collapse : Clause<"collapse"> { let clangClass = "OMPCollapseClause"; }
-def OMPC_Default : Clause<"default"> { let clangClass = "OMPDefaultClause"; }
-def OMPC_Private : Clause<"private"> { let clangClass = "OMPPrivateClause"; }
 def OMPC_FirstPrivate : Clause<"firstprivate"> {
   let clangClass = "OMPFirstprivateClause";
+  let flangClassValue = "OmpObjectList";
 }
 def OMPC_LastPrivate : Clause<"lastprivate"> {
   let clangClass = "OMPLastprivateClause";
+  let flangClassValue = "OmpObjectList";
+}
+def OMPC_Shared : Clause<"shared"> {
+  let clangClass = "OMPSharedClause";
+  let flangClassValue = "OmpObjectList";
 }
-def OMPC_Shared : Clause<"shared"> { let clangClass = "OMPSharedClause"; }
 def OMPC_Reduction : Clause<"reduction"> {
   let clangClass = "OMPReductionClause";
+  let flangClass = "OmpReductionClause";
+}
+def OMPC_Linear : Clause<"linear"> {
+  let clangClass = "OMPLinearClause";
+  let flangClass = "OmpLinearClause";
+}
+def OMPC_Aligned : Clause<"aligned"> {
+  let clangClass = "OMPAlignedClause";
+  let flangClass = "OmpAlignedClause";
+}
+def OMPC_Copyin : Clause<"copyin"> {
+  let clangClass = "OMPCopyinClause";
+  let flangClassValue = "OmpObjectList";
 }
-def OMPC_Linear : Clause<"linear"> { let clangClass = "OMPLinearClause"; }
-def OMPC_Aligned : Clause<"aligned"> { let clangClass = "OMPAlignedClause"; }
-def OMPC_Copyin : Clause<"copyin"> { let clangClass = "OMPCopyinClause"; }
 def OMPC_CopyPrivate : Clause<"copyprivate"> {
   let clangClass = "OMPCopyprivateClause";
+  let flangClassValue = "OmpObjectList";
 }
 def OMPC_ProcBind : Clause<"proc_bind"> {
   let clangClass = "OMPProcBindClause";
+  let flangClass = "OmpProcBindClause";
+}
+def OMPC_Schedule : Clause<"schedule"> {
+  let clangClass = "OMPScheduleClause";
+  let flangClass = "OmpScheduleClause";
+}
+def OMPC_Ordered : Clause<"ordered"> {
+  let clangClass = "OMPOrderedClause";
+  let flangClassValue = "ScalarIntConstantExpr";
+  let isValueOptional = 1;
+}
+def OMPC_NoWait : Clause<"nowait"> {
+  let clangClass = "OMPNowaitClause";
+  let flangClass = "OmpNowait";
 }
-def OMPC_Schedule : Clause<"schedule"> { let clangClass = "OMPScheduleClause"; }
-def OMPC_Ordered : Clause<"ordered"> { let clangClass = "OMPOrderedClause"; }
-def OMPC_NoWait : Clause<"nowait"> { let clangClass = "OMPNowaitClause"; }
 def OMPC_Untied : Clause<"untied"> { let clangClass = "OMPUntiedClause"; }
 def OMPC_Mergeable : Clause<"mergeable"> {
   let clangClass = "OMPMergeableClause";
@@ -79,47 +129,70 @@ def OMPC_AcqRel : Clause<"acq_rel"> { let clangClass = "OMPAcqRelClause"; }
 def OMPC_Acquire : Clause<"acquire"> { let clangClass = "OMPAcquireClause"; }
 def OMPC_Release : Clause<"release"> { let clangClass = "OMPReleaseClause"; }
 def OMPC_Relaxed : Clause<"relaxed"> { let clangClass = "OMPRelaxedClause"; }
-def OMPC_Depend : Clause<"depend"> { let clangClass = "OMPDependClause"; }
-def OMPC_Device : Clause<"device"> { let clangClass = "OMPDeviceClause"; }
+def OMPC_Depend : Clause<"depend"> {
+  let clangClass = "OMPDependClause";
+  let flangClass = "OmpDependClause";
+}
+def OMPC_Device : Clause<"device"> {
+  let clangClass = "OMPDeviceClause";
+  let flangClassValue = "ScalarIntExpr";
+}
 def OMPC_Threads : Clause<"threads"> { let clangClass = "OMPThreadsClause"; }
 def OMPC_Simd : Clause<"simd"> { let clangClass = "OMPSIMDClause"; }
-def OMPC_Map : Clause<"map"> { let clangClass = "OMPMapClause"; }
+def OMPC_Map : Clause<"map"> {
+  let clangClass = "OMPMapClause";
+  let flangClass = "OmpMapClause";
+}
 def OMPC_NumTeams : Clause<"num_teams"> {
   let clangClass = "OMPNumTeamsClause";
+  let flangClassValue = "ScalarIntExpr";
 }
 def OMPC_ThreadLimit : Clause<"thread_limit"> {
   let clangClass = "OMPThreadLimitClause";
+  let flangClassValue = "ScalarIntExpr";
 }
 def OMPC_Priority : Clause<"priority"> {
   let clangClass = "OMPPriorityClause";
+  let flangClassValue = "ScalarIntExpr";
 }
 def OMPC_GrainSize : Clause<"grainsize"> {
   let clangClass = "OMPGrainsizeClause";
+  let flangClassValue = "ScalarIntExpr";
 }
 def OMPC_NoGroup : Clause<"nogroup"> {
   let clangClass = "OMPNogroupClause";
 }
 def OMPC_NumTasks : Clause<"num_tasks"> {
   let clangClass = "OMPNumTasksClause";
+  let flangClassValue = "ScalarIntExpr";
 }
 def OMPC_Hint : Clause<"hint"> {
   let clangClass = "OMPHintClause";
 }
 def OMPC_DistSchedule : Clause<"dist_schedule"> {
   let clangClass = "OMPDistScheduleClause";
+  let flangClassValue = "ScalarIntExpr";
+  let isValueOptional = 1;
 }
 def OMPC_DefaultMap : Clause<"defaultmap"> {
   let clangClass = "OMPDefaultmapClause";
+  let flangClass = "OmpDefaultmapClause";
 }
 def OMPC_To : Clause<"to"> {
   let clangClass = "OMPToClause";
+  let flangClassValue = "OmpObjectList";
+}
+def OMPC_From : Clause<"from"> {
+  let clangClass = "OMPFromClause";
+  let flangClassValue = "OmpObjectList";
 }
-def OMPC_From : Clause<"from"> { let clangClass = "OMPFromClause"; }
 def OMPC_UseDevicePtr : Clause<"use_device_ptr"> {
   let clangClass = "OMPUseDevicePtrClause";
+  let flangClassValue = "std::list<Name>";
 }
 def OMPC_IsDevicePtr : Clause<"is_device_ptr"> {
   let clangClass = "OMPIsDevicePtrClause";
+  let flangClassValue = "std::list<Name>";
 }
 def OMPC_TaskReduction : Clause<"task_reduction"> {
   let clangClass = "OMPTaskReductionClause";
@@ -144,6 +217,7 @@ def OMPC_AtomicDefaultMemOrder : Clause<"atomic_default_mem_order"> {
 }
 def OMPC_Allocate : Clause<"allocate"> {
   let clangClass = "OMPAllocateClause";
+  let flangClass = "OmpAllocateClause";
 }
 def OMPC_NonTemporal : Clause<"nontemporal"> {
   let clangClass = "OMPNontemporalClause";
@@ -172,7 +246,9 @@ def OMPC_Affinity : Clause<"affinity"> {
 def OMPC_UseDeviceAddr : Clause<"use_device_addr"> {
   let clangClass = "OMPUseDeviceAddrClause";
 }
-def OMPC_Uniform : Clause<"uniform"> {}
+def OMPC_Uniform : Clause<"uniform"> {
+  let flangClassValue = "std::list<Name>";
+}
 def OMPC_DeviceType : Clause<"device_type"> {}
 def OMPC_Match : Clause<"match"> {}
 def OMPC_Depobj : Clause<"depobj"> {
@@ -191,7 +267,9 @@ def OMPC_Unknown : Clause<"unknown"> {
   let isImplicit = 1;
   let isDefault = 1;
 }
-def OMPC_Link : Clause<"link"> {}
+def OMPC_Link : Clause<"link"> {
+  let flangClassValue = "OmpObjectList";
+}
 def OMPC_Inbranch : Clause<"inbranch"> {}
 def OMPC_Notinbranch : Clause<"notinbranch"> {}
 
diff --git a/test/TableGen/directive1.td b/test/TableGen/directive1.td
index 905d6e28c4f..f647a03814c 100644
--- a/test/TableGen/directive1.td
+++ b/test/TableGen/directive1.td
@@ -12,10 +12,15 @@ def TestDirectiveLanguage : DirectiveLanguage {
   let clausePrefix = "TDLC_";
   let makeEnumAvailableInNamespace = 1;
   let enableBitmaskEnumInNamespace = 1;
+  let flangClauseBaseClass = "TdlClause";
 }
 
-def TDLC_ClauseA : Clause<"clausea"> {}
+def TDLC_ClauseA : Clause<"clausea"> {
+  let flangClass = "TdlClauseA";
+}
 def TDLC_ClauseB : Clause<"clauseb"> {
+  let flangClassValue = "IntExpr";
+  let isValueOptional = 1;
   let isDefault = 1;
 }
 
@@ -173,4 +178,27 @@ def TDL_DirA : Directive<"dira"> {
 // GEN-NEXT:  }
 // GEN-EMPTY:
 // GEN-NEXT:  #endif // GEN_FLANG_DIRECTIVE_CLAUSE_MAP
+// GEN-EMPTY:
+// GEN-NEXT:  #ifdef GEN_FLANG_CLAUSE_PARSER_CLASSES
+// GEN-NEXT:  #undef GEN_FLANG_CLAUSE_PARSER_CLASSES
+// GEN-EMPTY:
+// GEN-NEXT:  WRAPPER_CLASS(Clauseb, std::optional<IntExpr>);
+// GEN-EMPTY:
+// GEN-NEXT:  #endif // GEN_FLANG_CLAUSE_PARSER_CLASSES
+// GEN-EMPTY:
+// GEN-NEXT:  #ifdef GEN_FLANG_CLAUSE_PARSER_CLASSES_LIST
+// GEN-NEXT:  #undef GEN_FLANG_CLAUSE_PARSER_CLASSES_LIST
+// GEN-EMPTY:
+// GEN-NEXT:  TdlClauseA
+// GEN-NEXT:  , Clauseb
+// GEN-EMPTY:
+// GEN-NEXT:  #endif // GEN_FLANG_CLAUSE_PARSER_CLASSES_LIST
+// GEN-EMPTY:
+// GEN-NEXT:  #ifdef GEN_FLANG_DUMP_PARSE_TREE_CLAUSES
+// GEN-NEXT:  #undef GEN_FLANG_DUMP_PARSE_TREE_CLAUSES
+// GEN-EMPTY:
+// GEN-NEXT:  NODE(TdlClause, Clauseb)
+// GEN-EMPTY:
+// GEN-NEXT:  #endif // GEN_FLANG_DUMP_PARSE_TREE_CLAUSES
+
 
diff --git a/test/TableGen/directive2.td b/test/TableGen/directive2.td
index 02f9d4ec40e..ed2ac769084 100644
--- a/test/TableGen/directive2.td
+++ b/test/TableGen/directive2.td
@@ -11,6 +11,7 @@ def TestDirectiveLanguage : DirectiveLanguage {
   let directivePrefix = "TDLD_";
   let clausePrefix = "TDLC_";
   let includeHeader = "tdl.h.inc";
+  let flangClauseBaseClass = "TdlClause";
 }
 
 def TDLC_ClauseA : Clause<"clausea"> {
@@ -18,6 +19,7 @@ def TDLC_ClauseA : Clause<"clausea"> {
 }
 def TDLC_ClauseB : Clause<"clauseb"> {
   let isDefault = 1;
+  let flangClassValue = "IntExpr";
 }
 
 def TDL_DirA : Directive<"dira"> {
@@ -164,3 +166,28 @@ def TDL_DirA : Directive<"dira"> {
 // GEN-NEXT: }
 // GEN-EMPTY:
 // GEN-NEXT: #endif // GEN_FLANG_DIRECTIVE_CLAUSE_MAP
+// GEN-EMPTY:
+// GEN-NEXT:  #ifdef GEN_FLANG_CLAUSE_PARSER_CLASSES
+// GEN-NEXT:  #undef GEN_FLANG_CLAUSE_PARSER_CLASSES
+// GEN-EMPTY:
+// GEN-NEXT:  EMPTY_CLASS(Clausea);
+// GEN-NEXT:  WRAPPER_CLASS(Clauseb, IntExpr);
+// GEN-EMPTY:
+// GEN-NEXT:  #endif // GEN_FLANG_CLAUSE_PARSER_CLASSES
+// GEN-EMPTY:
+// GEN-NEXT:  #ifdef GEN_FLANG_CLAUSE_PARSER_CLASSES_LIST
+// GEN-NEXT:  #undef GEN_FLANG_CLAUSE_PARSER_CLASSES_LIST
+// GEN-EMPTY:
+// GEN-NEXT:  Clausea
+// GEN-NEXT:  , Clauseb
+// GEN-EMPTY:
+// GEN-NEXT:  #endif // GEN_FLANG_CLAUSE_PARSER_CLASSES_LIST
+// GEN-EMPTY:
+// GEN-NEXT:  #ifdef GEN_FLANG_DUMP_PARSE_TREE_CLAUSES
+// GEN-NEXT:  #undef GEN_FLANG_DUMP_PARSE_TREE_CLAUSES
+// GEN-EMPTY:
+// GEN-NEXT:  NODE(TdlClause, Clausea)
+// GEN-NEXT:  NODE(TdlClause, Clauseb)
+// GEN-EMPTY:
+// GEN-NEXT:  #endif // GEN_FLANG_DUMP_PARSE_TREE_CLAUSES
+
diff --git a/utils/TableGen/DirectiveEmitter.cpp b/utils/TableGen/DirectiveEmitter.cpp
index 60c80eb09d7..ff35264f7c7 100644
--- a/utils/TableGen/DirectiveEmitter.cpp
+++ b/utils/TableGen/DirectiveEmitter.cpp
@@ -68,6 +68,10 @@ public:
     return Def->getValueAsString("clauseEnumSetClass");
   }
 
+  StringRef getFlangClauseBaseClass() const {
+    return Def->getValueAsString("flangClauseBaseClass");
+  }
+
   bool hasMakeEnumAvailableInNamespace() const {
     return Def->getValueAsBit("makeEnumAvailableInNamespace");
   }
@@ -146,6 +150,35 @@ public:
     return Def->getValueAsString("flangClass");
   }
 
+  // Optional field.
+  StringRef getFlangClassValue() const {
+    return Def->getValueAsString("flangClassValue");
+  }
+
+  // Get the formatted name for Flang parser class. The generic formatted class
+  // name is constructed from the name were the first letter of each word is
+  // captitalized and the underscores are removed.
+  // ex: async -> Async
+  //     num_threads -> NumThreads
+  std::string getFormattedParserClassName() {
+    StringRef Name = Def->getValueAsString("name");
+    std::string N = Name.str();
+    bool Cap = true;
+    std::transform(N.begin(), N.end(), N.begin(), [&Cap](unsigned char C) {
+      if (Cap == true) {
+        C = std::toupper(C);
+        Cap = false;
+      } else if (C == '_') {
+        Cap = true;
+      }
+      return C;
+    });
+    N.erase(std::remove(N.begin(), N.end(), '_'), N.end());
+    return N;
+  }
+
+  bool isValueOptional() const { return Def->getValueAsBit("isValueOptional"); }
+
   bool isImplict() const { return Def->getValueAsBit("isImplicit"); }
 };
 
@@ -489,15 +522,89 @@ void GenerateDirectiveClauseMap(const std::vector<Record *> &Directives,
   OS << "}\n";
 }
 
+// Generate classes entry for Flang clauses in the Flang parse-tree
+// If the clause as a non-generic class, no entry is generated.
+// If the clause does not hold a value, an EMPTY_CLASS is used.
+// If the clause class is generic then a WRAPPER_CLASS is used. When the value
+// is optional, the value class is wrapped into a std::optional.
+void GenerateFlangClauseParserClass(const std::vector<Record *> &Clauses,
+                                    raw_ostream &OS) {
+
+  IfDefScope Scope("GEN_FLANG_CLAUSE_PARSER_CLASSES", OS);
+
+  OS << "\n";
+
+  for (const auto &C : Clauses) {
+    Clause Clause{C};
+    // Clause has a non generic class.
+    if (!Clause.getFlangClass().empty())
+      continue;
+    // G
+    if (!Clause.getFlangClassValue().empty()) {
+      if (Clause.isValueOptional()) {
+        OS << "WRAPPER_CLASS(" << Clause.getFormattedParserClassName()
+           << ", std::optional<" << Clause.getFlangClassValue() << ">);\n";
+      } else {
+        OS << "WRAPPER_CLASS(" << Clause.getFormattedParserClassName() << ", "
+           << Clause.getFlangClassValue() << ");\n";
+      }
+    } else {
+      OS << "EMPTY_CLASS(" << Clause.getFormattedParserClassName() << ");\n";
+    }
+  }
+}
+
+// Generate a list of the different clause classes for Flang.
+void GenerateFlangClauseParserClassList(const std::vector<Record *> &Clauses,
+                                        raw_ostream &OS) {
+
+  IfDefScope Scope("GEN_FLANG_CLAUSE_PARSER_CLASSES_LIST", OS);
+
+  OS << "\n";
+  llvm::interleaveComma(Clauses, OS, [&](Record *C) {
+    Clause Clause{C};
+    if (Clause.getFlangClass().empty())
+      OS << Clause.getFormattedParserClassName() << "\n";
+    else
+      OS << Clause.getFlangClass() << "\n";
+  });
+}
+
+// Generate dump node list for the clauses holding a generic class name.
+void GenerateFlangClauseDump(const std::vector<Record *> &Clauses,
+                             const DirectiveLanguage &DirLang,
+                             raw_ostream &OS) {
+
+  IfDefScope Scope("GEN_FLANG_DUMP_PARSE_TREE_CLAUSES", OS);
+
+  OS << "\n";
+  for (const auto &C : Clauses) {
+    Clause Clause{C};
+    // Clause has a non generic class.
+    if (!Clause.getFlangClass().empty())
+      continue;
+
+    OS << "NODE(" << DirLang.getFlangClauseBaseClass() << ", "
+       << Clause.getFormattedParserClassName() << ")\n";
+  }
+}
+
 // Generate the implemenation section for the enumeration in the directive
 // language
 void EmitDirectivesFlangImpl(const std::vector<Record *> &Directives,
+                             const std::vector<Record *> &Clauses,
                              raw_ostream &OS,
                              DirectiveLanguage &DirectiveLanguage) {
 
   GenerateDirectiveClauseSets(Directives, OS, DirectiveLanguage);
 
   GenerateDirectiveClauseMap(Directives, OS, DirectiveLanguage);
+
+  GenerateFlangClauseParserClass(Clauses, OS);
+
+  GenerateFlangClauseParserClassList(Clauses, OS);
+
+  GenerateFlangClauseDump(Clauses, DirectiveLanguage, OS);
 }
 
 // Generate the implemenation section for the enumeration in the directive
@@ -513,8 +620,9 @@ void EmitDirectivesGen(RecordKeeper &Records, raw_ostream &OS) {
   }
 
   const auto &Directives = Records.getAllDerivedDefinitions("Directive");
+  const auto &Clauses = Records.getAllDerivedDefinitions("Clause");
   DirectiveLanguage DirectiveLanguage{DirectiveLanguages[0]};
-  EmitDirectivesFlangImpl(Directives, OS, DirectiveLanguage);
+  EmitDirectivesFlangImpl(Directives, Clauses, OS, DirectiveLanguage);
 }
 
 // Generate the implemenation for the enumeration in the directive