[Frontend] Add leaf constructs and association to OpenMP/ACC directiv…

…es (#83625)

Add members "leafConstructs" and "association" to .td describing
OpenMP/ACC directives. The naming follows the terminology used in the
OpenMP standard: a "leaf" construct is a construct that is itself not a
composition or a combination of other constructs, and "association" is
the source language construct to which the directive applies (e.g. loop,
block, etc.)

The tblgen-generated output then contains two additional functions
- getLeafConstructs(D), and
- getDirectiveAssociation(D)
plus "enum class Association", all in namespaces "llvm::omp" and
"llvm::acc".

Note: getLeafConstructs returns an empty sequence for a construct that
is itself a leaf construct.

Use the new functions to simplify a few OpenMP-related functions in
clang.

clang/lib/Basic/OpenMPKinds.cpp

@@ -574,31 +574,7 @@ const char *clang::getOpenMPSimpleClauseTypeName(OpenMPClauseKind Kind,
 }
 
 bool clang::isOpenMPLoopDirective(OpenMPDirectiveKind DKind) {
-  return DKind == OMPD_simd || DKind == OMPD_for || DKind == OMPD_for_simd ||
-         DKind == OMPD_parallel_for || DKind == OMPD_parallel_for_simd ||
-         DKind == OMPD_taskloop || DKind == OMPD_taskloop_simd ||
-         DKind == OMPD_master_taskloop || DKind == OMPD_master_taskloop_simd ||
-         DKind == OMPD_parallel_master_taskloop ||
-         DKind == OMPD_parallel_master_taskloop_simd ||
-         DKind == OMPD_masked_taskloop || DKind == OMPD_masked_taskloop_simd ||
-         DKind == OMPD_parallel_masked_taskloop || DKind == OMPD_distribute ||
-         DKind == OMPD_parallel_masked_taskloop_simd ||
-         DKind == OMPD_target_parallel_for ||
-         DKind == OMPD_distribute_parallel_for ||
-         DKind == OMPD_distribute_parallel_for_simd ||
-         DKind == OMPD_distribute_simd ||
-         DKind == OMPD_target_parallel_for_simd || DKind == OMPD_target_simd ||
-         DKind == OMPD_teams_distribute ||
-         DKind == OMPD_teams_distribute_simd ||
-         DKind == OMPD_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_teams_distribute_parallel_for ||
-         DKind == OMPD_target_teams_distribute ||
-         DKind == OMPD_target_teams_distribute_parallel_for ||
-         DKind == OMPD_target_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_target_teams_distribute_simd || DKind == OMPD_tile ||
-         DKind == OMPD_unroll || DKind == OMPD_loop ||
-         DKind == OMPD_teams_loop || DKind == OMPD_target_teams_loop ||
-         DKind == OMPD_parallel_loop || DKind == OMPD_target_parallel_loop;
+  return getDirectiveAssociation(DKind) == Association::Loop;
 }
 
 bool clang::isOpenMPWorksharingDirective(OpenMPDirectiveKind DKind) {
@@ -619,44 +595,20 @@ bool clang::isOpenMPWorksharingDirective(OpenMPDirectiveKind DKind) {
 }
 
 bool clang::isOpenMPTaskLoopDirective(OpenMPDirectiveKind DKind) {
-  return DKind == OMPD_taskloop || DKind == OMPD_taskloop_simd ||
-         DKind == OMPD_master_taskloop || DKind == OMPD_master_taskloop_simd ||
-         DKind == OMPD_parallel_master_taskloop ||
-         DKind == OMPD_masked_taskloop || DKind == OMPD_masked_taskloop_simd ||
-         DKind == OMPD_parallel_masked_taskloop ||
-         DKind == OMPD_parallel_masked_taskloop_simd ||
-         DKind == OMPD_parallel_master_taskloop_simd;
+  return DKind == OMPD_taskloop ||
+         llvm::is_contained(getLeafConstructs(DKind), OMPD_taskloop);
 }
 
 bool clang::isOpenMPParallelDirective(OpenMPDirectiveKind DKind) {
-  return DKind == OMPD_parallel || DKind == OMPD_parallel_for ||
-         DKind == OMPD_parallel_for_simd || DKind == OMPD_parallel_sections ||
-         DKind == OMPD_target_parallel || DKind == OMPD_target_parallel_for ||
-         DKind == OMPD_distribute_parallel_for ||
-         DKind == OMPD_distribute_parallel_for_simd ||
-         DKind == OMPD_target_parallel_for_simd ||
-         DKind == OMPD_teams_distribute_parallel_for ||
-         DKind == OMPD_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_target_teams_distribute_parallel_for ||
-         DKind == OMPD_target_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_parallel_master || DKind == OMPD_parallel_masked ||
-         DKind == OMPD_parallel_master_taskloop ||
-         DKind == OMPD_parallel_master_taskloop_simd ||
-         DKind == OMPD_parallel_masked_taskloop ||
-         DKind == OMPD_parallel_masked_taskloop_simd ||
-         DKind == OMPD_parallel_loop || DKind == OMPD_target_parallel_loop ||
-         DKind == OMPD_teams_loop;
+  if (DKind == OMPD_teams_loop)
+    return true;
+  return DKind == OMPD_parallel ||
+         llvm::is_contained(getLeafConstructs(DKind), OMPD_parallel);
 }
 
 bool clang::isOpenMPTargetExecutionDirective(OpenMPDirectiveKind DKind) {
-  return DKind == OMPD_target || DKind == OMPD_target_parallel ||
-         DKind == OMPD_target_parallel_for ||
-         DKind == OMPD_target_parallel_for_simd || DKind == OMPD_target_simd ||
-         DKind == OMPD_target_teams || DKind == OMPD_target_teams_distribute ||
-         DKind == OMPD_target_teams_distribute_parallel_for ||
-         DKind == OMPD_target_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_target_teams_distribute_simd ||
-         DKind == OMPD_target_teams_loop || DKind == OMPD_target_parallel_loop;
+  return DKind == OMPD_target ||
+         llvm::is_contained(getLeafConstructs(DKind), OMPD_target);
 }
 
 bool clang::isOpenMPTargetDataManagementDirective(OpenMPDirectiveKind DKind) {
@@ -665,60 +617,45 @@ bool clang::isOpenMPTargetDataManagementDirective(OpenMPDirectiveKind DKind) {
 }
 
 bool clang::isOpenMPNestingTeamsDirective(OpenMPDirectiveKind DKind) {
-  return DKind == OMPD_teams || DKind == OMPD_teams_distribute ||
-         DKind == OMPD_teams_distribute_simd ||
-         DKind == OMPD_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_teams_distribute_parallel_for ||
-         DKind == OMPD_teams_loop;
+  if (DKind == OMPD_teams)
+    return true;
+  ArrayRef<Directive> Leaves = getLeafConstructs(DKind);
+  return !Leaves.empty() && Leaves.front() == OMPD_teams;
 }
 
 bool clang::isOpenMPTeamsDirective(OpenMPDirectiveKind DKind) {
-  return isOpenMPNestingTeamsDirective(DKind) || DKind == OMPD_target_teams ||
-         DKind == OMPD_target_teams_distribute ||
-         DKind == OMPD_target_teams_distribute_parallel_for ||
-         DKind == OMPD_target_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_target_teams_distribute_simd ||
-         DKind == OMPD_target_teams_loop;
+  return DKind == OMPD_teams ||
+         llvm::is_contained(getLeafConstructs(DKind), OMPD_teams);
 }
 
 bool clang::isOpenMPSimdDirective(OpenMPDirectiveKind DKind) {
-  return DKind == OMPD_simd || DKind == OMPD_for_simd ||
-         DKind == OMPD_parallel_for_simd || DKind == OMPD_taskloop_simd ||
-         DKind == OMPD_master_taskloop_simd ||
-         DKind == OMPD_masked_taskloop_simd ||
-         DKind == OMPD_parallel_master_taskloop_simd ||
-         DKind == OMPD_parallel_masked_taskloop_simd ||
-         DKind == OMPD_distribute_parallel_for_simd ||
-         DKind == OMPD_distribute_simd || DKind == OMPD_target_simd ||
-         DKind == OMPD_teams_distribute_simd ||
-         DKind == OMPD_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_target_teams_distribute_parallel_for_simd ||
-         DKind == OMPD_target_teams_distribute_simd ||
-         DKind == OMPD_target_parallel_for_simd;
+  // Avoid OMPD_declare_simd
+  if (getDirectiveAssociation(DKind) != Association::Loop)
+    return false;
+  // Formally, OMPD_end_do_simd also has a loop association, but
+  // it's a Fortran-specific directive.
+
+  return DKind == OMPD_simd ||
+         llvm::is_contained(getLeafConstructs(DKind), OMPD_simd);
 }
 
 bool clang::isOpenMPNestingDistributeDirective(OpenMPDirectiveKind Kind) {
-  return Kind == OMPD_distribute || Kind == OMPD_distribute_parallel_for ||
-         Kind == OMPD_distribute_parallel_for_simd ||
-         Kind == OMPD_distribute_simd;
-  // TODO add next directives.
+  if (Kind == OMPD_distribute)
+    return true;
+  ArrayRef<Directive> Leaves = getLeafConstructs(Kind);
+  return !Leaves.empty() && Leaves.front() == OMPD_distribute;
 }
 
 bool clang::isOpenMPDistributeDirective(OpenMPDirectiveKind Kind) {
-  return isOpenMPNestingDistributeDirective(Kind) ||
-         Kind == OMPD_teams_distribute || Kind == OMPD_teams_distribute_simd ||
-         Kind == OMPD_teams_distribute_parallel_for_simd ||
-         Kind == OMPD_teams_distribute_parallel_for ||
-         Kind == OMPD_target_teams_distribute ||
-         Kind == OMPD_target_teams_distribute_parallel_for ||
-         Kind == OMPD_target_teams_distribute_parallel_for_simd ||
-         Kind == OMPD_target_teams_distribute_simd;
+  return Kind == OMPD_distribute ||
+         llvm::is_contained(getLeafConstructs(Kind), OMPD_distribute);
 }
 
 bool clang::isOpenMPGenericLoopDirective(OpenMPDirectiveKind Kind) {
-  return Kind == OMPD_loop || Kind == OMPD_teams_loop ||
-         Kind == OMPD_target_teams_loop || Kind == OMPD_parallel_loop ||
-         Kind == OMPD_target_parallel_loop;
+  if (Kind == OMPD_loop)
+    return true;
+  ArrayRef<Directive> Leaves = getLeafConstructs(Kind);
+  return !Leaves.empty() && Leaves.back() == OMPD_loop;
 }
 
 bool clang::isOpenMPPrivate(OpenMPClauseKind Kind) {

llvm/include/llvm/Frontend/Directive/DirectiveBase.td

@@ -127,6 +127,35 @@ class VersionedClause<Clause c, int min = 1, int max = 0x7FFFFFFF> {
   int maxVersion = max;
 }
 
+// Kinds of directive associations.
+class Association<string n> {
+  string name = n;  // Name of the enum value in enum class Association.
+}
+// All of the AS_Xyz names are recognized by TableGen in order to calculate
+// the association in the AS_FromLeaves case.
+def AS_None : Association<"None"> {}              // No association
+def AS_Block : Association<"Block"> {}            // Block (incl. single
+                                                  // statement)
+def AS_Declaration : Association<"Declaration"> {}   // Declaration
+def AS_Delimited : Association<"Delimited"> {}    // Region delimited with
+                                                  // begin/end
+def AS_Loop : Association<"Loop"> {}              // Loop
+def AS_Separating : Association<"Separating"> {}  // Separates parts of a
+                                                  // construct
+
+def AS_FromLeaves : Association<"FromLeaves"> {}    // See below
+// AS_FromLeaves can be used for combined/composite directives, and the actual
+// association will be computed based on associations of the leaf constructs:
+//   (x + y) + z = x + (y + z)
+//   x + y = y + x
+//   x + x = x
+//   AS_None + x = x
+//   AS_Block + AS_Loop = AS_Loop
+// Other combinations are not allowed.
+// This association is not valid for leaf constructs.
+// The name "AS_FromLeaves" is recognized by TableGen, and there is no enum
+// generated for it.
+
 // Information about a specific directive.
 class Directive<string d> {
   // Name of the directive. Can be composite directive sepearted by whitespace.
@@ -152,6 +181,13 @@ class Directive<string d> {
   // List of clauses that are required.
   list<VersionedClause> requiredClauses = [];
 
+  // List of leaf constituent directives in the order in which they appear
+  // in the combined/composite directive.
+  list<Directive> leafConstructs = [];
+
   // Set directive used by default when unknown.
   bit isDefault = false;
+
+  // What the directive is associated with.
+  Association association = AS_FromLeaves;
 }

llvm/include/llvm/Frontend/OpenACC/ACC.td

@@ -266,7 +266,9 @@ def ACCC_Unknown : Clause<"unknown"> {
 //===----------------------------------------------------------------------===//
 
 // 2.12
-def ACC_Atomic : Directive<"atomic"> {}
+def ACC_Atomic : Directive<"atomic"> {
+  let association = AS_Block;
+}
 
 // 2.6.5
 def ACC_Data : Directive<"data"> {
@@ -290,6 +292,7 @@ def ACC_Data : Directive<"data"> {
     VersionedClause<ACCC_NoCreate>,
     VersionedClause<ACCC_Present>
   ];
+  let association = AS_Block;
 }
 
 // 2.13
@@ -304,6 +307,7 @@ def ACC_Declare : Directive<"declare"> {
     VersionedClause<ACCC_DeviceResident>,
     VersionedClause<ACCC_Link>
   ];
+  let association = AS_None;
 }
 
 // 2.5.3
@@ -329,6 +333,7 @@ def ACC_Kernels : Directive<"kernels"> {
     VersionedClause<ACCC_Self>,
     VersionedClause<ACCC_VectorLength>
   ];
+  let association = AS_Block;
 }
 
 // 2.5.1
@@ -357,6 +362,7 @@ def ACC_Parallel : Directive<"parallel"> {
     VersionedClause<ACCC_If>,
     VersionedClause<ACCC_Self>
   ];
+  let association = AS_Block;
 }
 
 // 2.5.2
@@ -384,6 +390,7 @@ def ACC_Serial : Directive<"serial"> {
     VersionedClause<ACCC_If>,
     VersionedClause<ACCC_Self>
   ];
+  let association = AS_Block;
 }
 
 // 2.9
@@ -403,10 +410,13 @@ def ACC_Loop : Directive<"loop"> {
     VersionedClause<ACCC_Independent>,
     VersionedClause<ACCC_Seq>
   ];
+  let association = AS_Loop;
 }
 
 // 2.10
-def ACC_Cache : Directive<"cache"> {}
+def ACC_Cache : Directive<"cache"> {
+  let association = AS_None;
+}
 
 // 2.14.1
 def ACC_Init : Directive<"init"> {
@@ -415,6 +425,7 @@ def ACC_Init : Directive<"init"> {
     VersionedClause<ACCC_DeviceType>,
     VersionedClause<ACCC_If>
   ];
+  let association = AS_None;
 }
 
 // 2.15.1
@@ -430,6 +441,7 @@ def ACC_Routine : Directive<"routine"> {
   let allowedOnceClauses = [
     VersionedClause<ACCC_NoHost>
   ];
+  let association = AS_Declaration;
 }
 
 // 2.14.3
@@ -448,6 +460,7 @@ def ACC_Set : Directive<"set"> {
     VersionedClause<ACCC_DeviceNum>,
     VersionedClause<ACCC_DeviceType>
   ];
+  let association = AS_None;
 }
 
 // 2.14.2
@@ -457,6 +470,7 @@ def ACC_Shutdown : Directive<"shutdown"> {
     VersionedClause<ACCC_DeviceType>,
     VersionedClause<ACCC_If>
   ];
+  let association = AS_None;
 }
 
 // 2.14.4
@@ -475,6 +489,7 @@ def ACC_Update : Directive<"update"> {
     VersionedClause<ACCC_Host>,
     VersionedClause<ACCC_Self>
   ];
+  let association = AS_None;
 }
 
 // 2.16.3
@@ -483,6 +498,7 @@ def ACC_Wait : Directive<"wait"> {
     VersionedClause<ACCC_Async>,
     VersionedClause<ACCC_If>
   ];
+  let association = AS_None;
 }
 
 // 2.14.6
@@ -499,6 +515,7 @@ def ACC_EnterData : Directive<"enter data"> {
     VersionedClause<ACCC_Create>,
     VersionedClause<ACCC_Copyin>
   ];
+  let association = AS_None;
 }
 
 // 2.14.7
@@ -516,6 +533,7 @@ def ACC_ExitData : Directive<"exit data"> {
     VersionedClause<ACCC_Delete>,
     VersionedClause<ACCC_Detach>
   ];
+  let association = AS_None;
 }
 
 // 2.8
@@ -527,6 +545,7 @@ def ACC_HostData : Directive<"host_data"> {
   let requiredClauses = [
     VersionedClause<ACCC_UseDevice>
   ];
+  let association = AS_Block;
 }
 
 // 2.11
@@ -564,6 +583,7 @@ def ACC_KernelsLoop : Directive<"kernels loop"> {
     VersionedClause<ACCC_Independent>,
     VersionedClause<ACCC_Seq>
   ];
+  let leafConstructs = [ACC_Kernels, ACC_Loop];
 }
 
 // 2.11
@@ -602,6 +622,7 @@ def ACC_ParallelLoop : Directive<"parallel loop"> {
     VersionedClause<ACCC_Independent>,
     VersionedClause<ACCC_Seq>
   ];
+  let leafConstructs = [ACC_Parallel, ACC_Loop];
 }
 
 // 2.11
@@ -637,8 +658,10 @@ def ACC_SerialLoop : Directive<"serial loop"> {
     VersionedClause<ACCC_Independent>,
     VersionedClause<ACCC_Seq>
   ];
+  let leafConstructs = [ACC_Serial, ACC_Loop];
 }
 
 def ACC_Unknown : Directive<"unknown"> {
   let isDefault = true;
+  let association = AS_None;
 }