[OpenMP][Clang] Add codegen support for dyn_groupprivate clause (llvm#152830)

This adds the codegen support for the dyn_groupprivate clause.

Author: kevinsala

clang/lib/CodeGen/CGOpenMPRuntime.cpp

@@ -10013,19 +10013,44 @@ static llvm::Value *emitDeviceID(
   return DeviceID;
 }
 
-static llvm::Value *emitDynCGGroupMem(const OMPExecutableDirective &D,
-                                      CodeGenFunction &CGF) {
-  llvm::Value *DynCGroupMem = CGF.Builder.getInt32(0);
-
-  if (auto *DynMemClause = D.getSingleClause<OMPXDynCGroupMemClause>()) {
-    CodeGenFunction::RunCleanupsScope DynCGroupMemScope(CGF);
-    llvm::Value *DynCGroupMemVal = CGF.EmitScalarExpr(
-        DynMemClause->getSize(), /*IgnoreResultAssign=*/true);
-    DynCGroupMem = CGF.Builder.CreateIntCast(DynCGroupMemVal, CGF.Int32Ty,
-                                             /*isSigned=*/false);
+static std::pair<llvm::Value *, OMPDynGroupprivateFallbackType>
+emitDynCGroupMem(const OMPExecutableDirective &D, CodeGenFunction &CGF) {
+  llvm::Value *DynGP = CGF.Builder.getInt32(0);
+  auto DynGPFallback = OMPDynGroupprivateFallbackType::Abort;
+
+  if (auto *DynGPClause = D.getSingleClause<OMPDynGroupprivateClause>()) {
+    CodeGenFunction::RunCleanupsScope DynGPScope(CGF);
+    llvm::Value *DynGPVal =
+        CGF.EmitScalarExpr(DynGPClause->getSize(), /*IgnoreResultAssign=*/true);
+    DynGP = CGF.Builder.CreateIntCast(DynGPVal, CGF.Int32Ty,
+                                      /*isSigned=*/false);
+    auto FallbackModifier = DynGPClause->getDynGroupprivateFallbackModifier();
+    switch (FallbackModifier) {
+    case OMPC_DYN_GROUPPRIVATE_FALLBACK_abort:
+      DynGPFallback = OMPDynGroupprivateFallbackType::Abort;
+      break;
+    case OMPC_DYN_GROUPPRIVATE_FALLBACK_null:
+      DynGPFallback = OMPDynGroupprivateFallbackType::Null;
+      break;
+    case OMPC_DYN_GROUPPRIVATE_FALLBACK_default_mem:
+    case OMPC_DYN_GROUPPRIVATE_FALLBACK_unknown:
+      // This is the default for dyn_groupprivate.
+      DynGPFallback = OMPDynGroupprivateFallbackType::DefaultMem;
+      break;
+    default:
+      llvm_unreachable("Unknown fallback modifier for OpenMP dyn_groupprivate");
+    }
+  } else if (auto *OMPXDynCGClause =
+                 D.getSingleClause<OMPXDynCGroupMemClause>()) {
+    CodeGenFunction::RunCleanupsScope DynCGMemScope(CGF);
+    llvm::Value *DynCGMemVal = CGF.EmitScalarExpr(OMPXDynCGClause->getSize(),
+                                                  /*IgnoreResultAssign=*/true);
+    DynGP = CGF.Builder.CreateIntCast(DynCGMemVal, CGF.Int32Ty,
+                                      /*isSigned=*/false);
   }
-  return DynCGroupMem;
+  return {DynGP, DynGPFallback};
 }
+
 static void genMapInfoForCaptures(
     MappableExprsHandler &MEHandler, CodeGenFunction &CGF,
     const CapturedStmt &CS, llvm::SmallVectorImpl<llvm::Value *> &CapturedVars,
@@ -10234,7 +10259,7 @@ static void emitTargetCallKernelLaunch(
     llvm::Value *RTLoc = OMPRuntime->emitUpdateLocation(CGF, D.getBeginLoc());
     llvm::Value *NumIterations =
         OMPRuntime->emitTargetNumIterationsCall(CGF, D, SizeEmitter);
-    llvm::Value *DynCGGroupMem = emitDynCGGroupMem(D, CGF);
+    auto [DynCGroupMem, DynCGroupMemFallback] = emitDynCGroupMem(D, CGF);
     llvm::OpenMPIRBuilder::InsertPointTy AllocaIP(
         CGF.AllocaInsertPt->getParent(), CGF.AllocaInsertPt->getIterator());
 
@@ -10244,7 +10269,7 @@ static void emitTargetCallKernelLaunch(
 
     llvm::OpenMPIRBuilder::TargetKernelArgs Args(
         NumTargetItems, RTArgs, NumIterations, NumTeams, NumThreads,
-        DynCGGroupMem, HasNoWait);
+        DynCGroupMem, HasNoWait, DynCGroupMemFallback);
 
     llvm::OpenMPIRBuilder::InsertPointTy AfterIP =
         cantFail(OMPRuntime->getOMPBuilder().emitKernelLaunch(