[OpenMP][OpenMPIRBuilder] Add kernel launch codegen to emitTargetCall

[jsjodin]

Summary

This patch adds code emission in emitTargetCall to call the OpenMP runtime to launch an kernel, and to call the fallback host implementation if the launch fails.

[jsjodin]

Remove llvm::

[jsjodin]

Rebase.

[jdoerfert]

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4390

Is the AllocaIP expected to be used later?

4403

Is this NumThreads or ThreadLimit, I assume the latter.

4419

[jsjodin]

Fixes from review feedback. Rebase.

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4390

Even if it is, it should not be part of this patch. I will remove it. Good catch.

4403

It should be the equivalent of llvm::Value *NumThreads = OMPRuntime->emitNumThreadsForTargetDirective(CGF, D); in clang, which looks a bit involved, but is essentially ThreadLimit from what I can tell.

[jsjodin]

Ping for review. If someone can take a look at this patch I would appreciate it.

[kiranchandramohan]

This patch adds code emission in emitTargetCall to call the OpenMP runtime to launch an kernel, and to call the fallback host implementation if the launch fails.

This is not visible in the IR generated from MLIR. Could you add a test?

Also could @TIFitis review this patch?

[TIFitis]

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4411

Expand type here.

4416

This allows debug info to be accurately generated.

4452–4455

No need to explicitly specify OpenMPIRBuilder namespace here.

4453

Same, remove explicit namespace.

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

5077–5078

Maybe we can replace this with OMPBuilder.getOrCreateDefaultSrcLocStr?

Also it is fine to leave the Names empty if not available.

5084

Can you please check if this works with function arguments?

AFAIK getTypeAllocSize doesn't work on function arguments, in that case we might want to move this function as a callback to MLIR.

[TIFitis]

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

5066–5073

Given the args are added by this tests themselves, I think this condition is not needed.

5084

Sorry, forgot this function is inside test. Please ignore above comment.

[jsjodin]

Updated test to check new kernel launch codegen. Fixed nits.

[jsjodin]

Marked fixed items, one more to do that I didn't get to.

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

5066–5073

Given the args are added by this tests themselves, I think this condition is not needed.

Sure, I will remove the if.

5077–5078

I'm leaving it for now since it doesn't affect the test.

[jsjodin]

Removed useless condition in test.

[jsjodin]

Finished addressing feedback.

[TIFitis]

LGTM

[jsjodin]

@kiranchandramohan did you have any more feedback about the patch?

[kiranchandramohan]

In D155633#4586255, @jsjodin wrote:

@kiranchandramohan did you have any more feedback about the patch?

I have not gone through the patch in detail. If you feel the patch is in good shape and @jdoerfert has not further comments you may go ahead.

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

5137–5154

Nit: leftover debug?

[jsjodin]

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

5137–5154

Nit: leftover debug?

Yes, thank you for finding that. I will remove this and update the parameter names CreateDefaultMapInfos.

llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h

public:
   /// DupNoPriv: If we need device pointer privatization, we need
   /// to emit the body of the region with no privatization in the 'else' branch
   /// of the conditional.
   /// NoPriv: If we don't require privatization of device
   /// pointers, we emit the body in between the runtime calls. This avoids
   /// duplicating the body code.
   enum BodyGenTy { Priv, DupNoPriv, NoPriv };
 
+  /// Callback type for creating the map infos for the kernel parameters.
+  /// \param CodeGenIP is the insertion point where code should be generated,
+  ///        if any.
+  using GenMapInfoCallbackTy =
+      function_ref<MapInfosTy &(InsertPointTy CodeGenIP)>;
+
   /// Generator for '#omp target data'
   ///
   /// \param Loc The location where the target data construct was encountered.
   /// \param AllocaIP The insertion points to be used for alloca instructions.
   /// \param CodeGenIP The insertion point at which the target directive code
   /// should be placed.
   /// \param IsBegin If true then emits begin mapper call otherwise emits
   /// end mapper call.
   /// \param DeviceID Stores the DeviceID from the device clause.
   /// \param IfCond Value which corresponds to the if clause condition.
   /// \param Info Stores all information realted to the Target Data directive.
   /// \param GenMapInfoCB Callback that populates the MapInfos and returns.
   /// \param BodyGenCB Optional Callback to generate the region code.
   /// \param DeviceAddrCB Optional callback to generate code related to
   /// use_device_ptr and use_device_addr.
   /// \param CustomMapperCB Optional callback to generate code related to
   /// custom mappers.
   OpenMPIRBuilder::InsertPointTy createTargetData(
       const LocationDescription &Loc, InsertPointTy AllocaIP,
       InsertPointTy CodeGenIP, Value *DeviceID, Value *IfCond,
-      TargetDataInfo &Info,
-      function_ref<MapInfosTy &(InsertPointTy CodeGenIP)> GenMapInfoCB,
+      TargetDataInfo &Info, GenMapInfoCallbackTy GenMapInfoCB,
       omp::RuntimeFunction *MapperFunc = nullptr,
       function_ref<InsertPointTy(InsertPointTy CodeGenIP,
                                  BodyGenTy BodyGenType)>
           BodyGenCB = nullptr,
       function_ref<void(unsigned int, Value *)> DeviceAddrCB = nullptr,
       function_ref<Value *(unsigned int)> CustomMapperCB = nullptr,
       Value *SrcLocInfo = nullptr);
 
   using TargetBodyGenCallbackTy = function_ref<InsertPointTy(
       InsertPointTy AllocaIP, InsertPointTy CodeGenIP)>;
 
   /// Generator for '#omp target'
   ///
   /// \param Loc where the target data construct was encountered.
   /// \param CodeGenIP The insertion point where the call to the outlined
   /// function should be emitted.
   /// \param EntryInfo The entry information about the function.
   /// \param NumTeams Number of teams specified in the num_teams clause.
   /// \param NumThreads Number of teams specified in the thread_limit clause.
   /// \param Inputs The input values to the region that will be passed.
   /// as arguments to the outlined function.
   /// \param BodyGenCB Callback that will generate the region code.
   InsertPointTy createTarget(const LocationDescription &Loc,
+                             OpenMPIRBuilder::InsertPointTy AllocaIP,
                              OpenMPIRBuilder::InsertPointTy CodeGenIP,
                              TargetRegionEntryInfo &EntryInfo, int32_t NumTeams,
                              int32_t NumThreads,
                              SmallVectorImpl<Value *> &Inputs,
+                             GenMapInfoCallbackTy GenMapInfoCB,
                              TargetBodyGenCallbackTy BodyGenCB);
 
   /// Declarations for LLVM-IR types (simple, array, function and structure) are
   /// generated below. Their names are defined and used in OpenMPKinds.def. Here
   /// we provide the declarations, the initializeTypes function will provide the
   /// values.
   ///
   ///{

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

OffloadInfoManager.registerTargetRegionEntryInfo(
       EntryInfo, EntryAddr, OutlinedFnID,
       OffloadEntriesInfoManager::OMPTargetRegionEntryTargetRegion);
   return OutlinedFnID;
 }
 
 OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createTargetData(
     const LocationDescription &Loc, InsertPointTy AllocaIP,
     InsertPointTy CodeGenIP, Value *DeviceID, Value *IfCond,
-    TargetDataInfo &Info,
-    function_ref<MapInfosTy &(InsertPointTy CodeGenIP)> GenMapInfoCB,
+    TargetDataInfo &Info, GenMapInfoCallbackTy GenMapInfoCB,
     omp::RuntimeFunction *MapperFunc,
     function_ref<InsertPointTy(InsertPointTy CodeGenIP, BodyGenTy BodyGenType)>
         BodyGenCB,
     function_ref<void(unsigned int, Value *)> DeviceAddrCB,
     function_ref<Value *(unsigned int)> CustomMapperCB, Value *SrcLocInfo) {
   if (!updateToLocation(Loc))
     return InsertPointTy();
 
createOutlinedFunction(OpenMPIRBuilder &OMPBuilder, IRBuilderBase &Builder,
   Builder.restoreIP(OldInsertPoint);
 
   return Func;
 }
 
 static void
 emitTargetOutlinedFunction(OpenMPIRBuilder &OMPBuilder, IRBuilderBase &Builder,
                            TargetRegionEntryInfo &EntryInfo,
-                           Function *&OutlinedFn, int32_t NumTeams,
-                           int32_t NumThreads, SmallVectorImpl<Value *> &Inputs,
-                           OpenMPIRBuilder::TargetBodyGenCallbackTy &CBFunc) {
+                           Function *&OutlinedFn, Constant *&OutlinedFnID,
+                           int32_t NumTeams, int32_t NumThreads,
+                           SmallVectorImpl<Value *> &Inputs,
+                           OpenMPIRBuilder::TargetBodyGenCallbackTy &CBFunc,
+                           OpenMPIRBuilder::InsertPointTy AllocaIP) {
 
   OpenMPIRBuilder::FunctionGenCallback &&GenerateOutlinedFunction =
-      [&OMPBuilder, &Builder, &Inputs, &CBFunc](StringRef EntryFnName) {
+      [&OMPBuilder, &Builder, &Inputs, &CBFunc,
+       &AllocaIP](StringRef EntryFnName) {
         return createOutlinedFunction(OMPBuilder, Builder, EntryFnName, Inputs,
                                       CBFunc);
       };
 
-  Constant *OutlinedFnID;
   OMPBuilder.emitTargetRegionFunction(EntryInfo, GenerateOutlinedFunction,
                                       NumTeams, NumThreads, true, OutlinedFn,
                                       OutlinedFnID);
 }
 
-static void emitTargetCall(IRBuilderBase &Builder, Function *OutlinedFn,
-                           SmallVectorImpl<Value *> &Args) {
-  // TODO: Add kernel launch call
+static void emitTargetCall(OpenMPIRBuilder &OMPBuilder, IRBuilderBase &Builder,
+                           OpenMPIRBuilder::InsertPointTy AllocaIP,
+                           Function *OutlinedFn, Constant *OutlinedFnID,
+                           int32_t NumTeams, int32_t NumThreads,
+                           SmallVectorImpl<Value *> &Args,
+                           OpenMPIRBuilder::GenMapInfoCallbackTy GenMapInfoCB) {
+
+  OpenMPIRBuilder::TargetDataInfo Info(
+      /*RequiresDevicePointerInfo=*/false,
+      /*SeparateBeginEndCalls=*/true);
+
+  auto MapInfo = GenMapInfoCB(Builder.saveIP());
+  OMPBuilder.emitOffloadingArrays(AllocaIP, Builder.saveIP(), MapInfo, Info,
+                                  /*IsNonContiguous=*/true);
+
+  OpenMPIRBuilder::TargetDataRTArgs RTArgs;
+  OMPBuilder.emitOffloadingArraysArgument(Builder, RTArgs, Info);
+
+  //  emitKernelLaunch
+  auto &&emitTargetCallFallbackCB =
+      [&](OpenMPIRBuilder::InsertPointTy IP) -> OpenMPIRBuilder::InsertPointTy {
+    Builder.restoreIP(IP);
     Builder.CreateCall(OutlinedFn, Args);
+    return Builder.saveIP();
+  };
+
+  unsigned NumTargetItems = MapInfo.BasePointers.size();
+  // TODO: Use correct device ID
+  Value *DeviceID = Builder.getInt64(OMP_DEVICEID_UNDEF);
+  Value *NumTeamsVal = Builder.getInt32(NumTeams);
+  Value *NumThreadsVal = Builder.getInt32(NumThreads);
+  uint32_t SrcLocStrSize;
+  Constant *SrcLocStr = OMPBuilder.getOrCreateDefaultSrcLocStr(SrcLocStrSize);
+  Value *RTLoc = OMPBuilder.getOrCreateIdent(SrcLocStr, SrcLocStrSize,
+                                             llvm::omp::IdentFlag(0), 0);
+  // TODO: Use correct NumIterations
+  Value *NumIterations = Builder.getInt64(0);
+  // TODO: Use correct DynCGGroupMem
+  Value *DynCGGroupMem = Builder.getInt32(0);
+
+  bool HasNoWait = false;
+
+  OpenMPIRBuilder::TargetKernelArgs KArgs(NumTargetItems, RTArgs, NumIterations,
+                                          NumTeamsVal, NumThreadsVal,
+                                          DynCGGroupMem, HasNoWait);
+
+  Builder.restoreIP(OMPBuilder.emitKernelLaunch(
+      Builder, OutlinedFn, OutlinedFnID, emitTargetCallFallbackCB, KArgs,
+      DeviceID, RTLoc, AllocaIP));
 }
 
 OpenMPIRBuilder::InsertPointTy OpenMPIRBuilder::createTarget(
-    const LocationDescription &Loc, OpenMPIRBuilder::InsertPointTy CodeGenIP,
-    TargetRegionEntryInfo &EntryInfo, int32_t NumTeams, int32_t NumThreads,
-    SmallVectorImpl<Value *> &Args, TargetBodyGenCallbackTy CBFunc) {
+    const LocationDescription &Loc, OpenMPIRBuilder::InsertPointTy AllocaIP,
+    OpenMPIRBuilder::InsertPointTy CodeGenIP, TargetRegionEntryInfo &EntryInfo,
+    int32_t NumTeams, int32_t NumThreads, SmallVectorImpl<Value *> &Args,
+    GenMapInfoCallbackTy GenMapInfoCB, TargetBodyGenCallbackTy CBFunc) {
   if (!updateToLocation(Loc))
     return InsertPointTy();
 
   Builder.restoreIP(CodeGenIP);
 
   Function *OutlinedFn;
-  emitTargetOutlinedFunction(*this, Builder, EntryInfo, OutlinedFn, NumTeams,
-                             NumThreads, Args, CBFunc);
+  Constant *OutlinedFnID;
+  emitTargetOutlinedFunction(*this, Builder, EntryInfo, OutlinedFn,
+                             OutlinedFnID, NumTeams, NumThreads, Args, CBFunc,
+                             AllocaIP);
   if (!Config.isTargetDevice())
-    emitTargetCall(Builder, OutlinedFn, Args);
+    emitTargetCall(*this, Builder, AllocaIP, OutlinedFn, OutlinedFnID, NumTeams,
+                   NumThreads, Args, GenMapInfoCB);
+
   return Builder.saveIP();
 }
 
 std::string OpenMPIRBuilder::getNameWithSeparators(ArrayRef<StringRef> Parts,
                                                    StringRef FirstSeparator,
                                                    StringRef Separator) {
   SmallString<128> Buffer;
   llvm::raw_svector_ostream OS(Buffer);

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

TEST_F(OpenMPIRBuilderTest, TargetDataRegion) {
   EXPECT_TRUE(TargetDataCall->getOperand(1)->getType()->isIntegerTy(64));
   EXPECT_TRUE(TargetDataCall->getOperand(2)->getType()->isIntegerTy(32));
   EXPECT_TRUE(TargetDataCall->getOperand(8)->getType()->isPointerTy());
 
   Builder.CreateRetVoid();
   EXPECT_FALSE(verifyModule(*M, &errs()));
 }
 
+namespace {
+// Some basic handling of argument mapping for the moment
+void CreateDefaultMapInfos(llvm::OpenMPIRBuilder &ompBuilder,
+                           llvm::SmallVectorImpl<llvm::Value *> &args,
+                           llvm::OpenMPIRBuilder::MapInfosTy &combinedInfo) {
+  for (auto arg : args) {
+    if (!arg->getType()->isPointerTy()) {
+      combinedInfo.BasePointers.clear();
+      combinedInfo.Pointers.clear();
+      combinedInfo.Sizes.clear();
+      combinedInfo.Types.clear();
+      combinedInfo.Names.clear();
+      return;
+    }
+    combinedInfo.BasePointers.emplace_back(arg);
+    combinedInfo.Pointers.emplace_back(arg);
+    uint32_t SrcLocStrSize;
+    combinedInfo.Names.emplace_back(ompBuilder.getOrCreateSrcLocStr(
+        "Unknown loc - stub implementation", SrcLocStrSize));
+    combinedInfo.Types.emplace_back(llvm::omp::OpenMPOffloadMappingFlags(
+        llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_TO |
+        llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_FROM |
+        llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_TARGET_PARAM));
+    combinedInfo.Sizes.emplace_back(ompBuilder.Builder.getInt64(
+        ompBuilder.M.getDataLayout().getTypeAllocSize(arg->getType())));
+  }
+}
+} // namespace
+
 TEST_F(OpenMPIRBuilderTest, TargetRegion) {
   using InsertPointTy = OpenMPIRBuilder::InsertPointTy;
   OpenMPIRBuilder OMPBuilder(*M);
   OMPBuilder.initialize();
   OpenMPIRBuilderConfig Config(false, false, false, false);
   OMPBuilder.setConfig(Config);
   F->setName("func");
   IRBuilder<> Builder(BB);
auto BodyGenCB = [&](InsertPointTy AllocaIP,
     return Builder.saveIP();
   };
 
   llvm::SmallVector<llvm::Value *> Inputs;
   Inputs.push_back(APtr);
   Inputs.push_back(BPtr);
   Inputs.push_back(CPtr);
 
+  llvm::OpenMPIRBuilder::MapInfosTy CombinedInfos;
+  auto GenMapInfoCB = [&](llvm::OpenMPIRBuilder::InsertPointTy codeGenIP)
+      -> llvm::OpenMPIRBuilder::MapInfosTy & {
+    CreateDefaultMapInfos(OMPBuilder, Inputs, CombinedInfos);
+    return CombinedInfos;
+  };
+
   TargetRegionEntryInfo EntryInfo("func", 42, 4711, 17);
   OpenMPIRBuilder::LocationDescription OmpLoc({Builder.saveIP(), DL});
-  Builder.restoreIP(OMPBuilder.createTarget(OmpLoc, Builder.saveIP(), EntryInfo,
-                                            -1, -1, Inputs, BodyGenCB));
+  Builder.restoreIP(OMPBuilder.createTarget(OmpLoc, Builder.saveIP(),
+                                            Builder.saveIP(), EntryInfo, -1, 0,
+                                            Inputs, GenMapInfoCB, BodyGenCB));
   OMPBuilder.finalize();
   Builder.CreateRetVoid();
 
-  // Check the outlined call
+  // Check the kernel launch sequence
   auto Iter = F->getEntryBlock().rbegin();
-  CallInst *Call = dyn_cast<CallInst>(&*(++Iter));
-  EXPECT_NE(Call, nullptr);
+  F->dump();
+  EXPECT_TRUE(isa<BranchInst>(&*(Iter)));
+  BranchInst *Branch = dyn_cast<BranchInst>(&*(Iter));
+  EXPECT_TRUE(isa<CmpInst>(&*(++Iter)));
+  EXPECT_TRUE(isa<CallInst>(&*(++Iter)));
+  CallInst *Call = dyn_cast<CallInst>(&*(Iter));
+
+  // Check that the kernel launch function is called
+  Function *KernelLaunchFunc = Call->getCalledFunction();
+  EXPECT_NE(KernelLaunchFunc, nullptr);
+  StringRef FunctionName = KernelLaunchFunc->getName();
+  EXPECT_TRUE(FunctionName.startswith("__tgt_target_kernel"));
+
+  // Check the fallback call
+  BasicBlock *FallbackBlock = Branch->getSuccessor(0);
+  Iter = FallbackBlock->rbegin();
+  CallInst *FCall = dyn_cast<CallInst>(&*(++Iter));
+  EXPECT_NE(FCall, nullptr);
 
   // Check that the correct aguments are passed in
-  for (auto ArgInput : zip(Call->args(), Inputs)) {
+  for (auto ArgInput : zip(FCall->args(), Inputs)) {
     EXPECT_EQ(std::get<0>(ArgInput), std::get<1>(ArgInput));
   }
 
   // Check that the outlined function exists with the expected prefix
-  Function *OutlinedFunc = Call->getCalledFunction();
+  Function *OutlinedFunc = FCall->getCalledFunction();
   EXPECT_NE(OutlinedFunc, nullptr);
-  StringRef FunctionName = OutlinedFunc->getName();
-  EXPECT_TRUE(FunctionName.startswith("__omp_offloading"));
+  StringRef FunctionName2 = OutlinedFunc->getName();
+  EXPECT_TRUE(FunctionName2.startswith("__omp_offloading"));
+
   EXPECT_FALSE(verifyModule(*M, &errs()));
 }
 
 TEST_F(OpenMPIRBuilderTest, TargetRegionDevice) {
   OpenMPIRBuilder OMPBuilder(*M);
   OMPBuilder.setConfig(OpenMPIRBuilderConfig(true, false, false, false));
   OMPBuilder.initialize();
 
   F->setName("func");
   IRBuilder<> Builder(BB);
   OpenMPIRBuilder::LocationDescription Loc({Builder.saveIP(), DL});
 
   LoadInst *Value = nullptr;
   StoreInst *TargetStore = nullptr;
   llvm::SmallVector<llvm::Value *, 2> CapturedArgs = {
       Constant::getNullValue(Type::getInt32PtrTy(Ctx)),
       Constant::getNullValue(Type::getInt32PtrTy(Ctx))};
 
+  llvm::OpenMPIRBuilder::MapInfosTy CombinedInfos;
+  auto GenMapInfoCB = [&](llvm::OpenMPIRBuilder::InsertPointTy codeGenIP)
+      -> llvm::OpenMPIRBuilder::MapInfosTy & {
+    CreateDefaultMapInfos(OMPBuilder, CapturedArgs, CombinedInfos);
+    return CombinedInfos;
+  };
+
   auto BodyGenCB = [&](OpenMPIRBuilder::InsertPointTy AllocaIP,
                        OpenMPIRBuilder::InsertPointTy CodeGenIP)
       -> OpenMPIRBuilder::InsertPointTy {
     Builder.restoreIP(CodeGenIP);
     Value = Builder.CreateLoad(Type::getInt32Ty(Ctx), CapturedArgs[0]);
     TargetStore = Builder.CreateStore(Value, CapturedArgs[1]);
     return Builder.saveIP();
   };
 
   IRBuilder<>::InsertPoint EntryIP(&F->getEntryBlock(),
                                    F->getEntryBlock().getFirstInsertionPt());
   TargetRegionEntryInfo EntryInfo("parent", /*DeviceID=*/1, /*FileID=*/2,
                                   /*Line=*/3, /*Count=*/0);
 
-  Builder.restoreIP(
-      OMPBuilder.createTarget(Loc, EntryIP, EntryInfo, /*NumTeams=*/-1,
-                              /*NumThreads=*/-1, CapturedArgs, BodyGenCB));
+  Builder.restoreIP(OMPBuilder.createTarget(
+      Loc, EntryIP, EntryIP, EntryInfo, /*NumTeams=*/-1,
+      /*NumThreads=*/0, CapturedArgs, GenMapInfoCB, BodyGenCB));
+
   Builder.CreateRetVoid();
   OMPBuilder.finalize();
 
   // Check outlined function
   EXPECT_FALSE(verifyModule(*M, &errs()));
   EXPECT_NE(TargetStore, nullptr);
   Function *OutlinedFn = TargetStore->getFunction();
   EXPECT_NE(F, OutlinedFn);

mlir/lib/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.cpp

int64_t getSizeInBytes(DataLayout &DL, const mlir::Type &type) {
   return 0;
 }
 
 static void genMapInfos(llvm::IRBuilderBase &builder,
                         LLVM::ModuleTranslation &moduleTranslation,
                         DataLayout &DL,
                         llvm::OpenMPIRBuilder::MapInfosTy &combinedInfo,
                         const SmallVector<Value> &mapOperands,
-                        const ArrayAttr &mapTypes) {
+                        const ArrayAttr &mapTypes,
+                        bool IsTargetParams = false) {
   // Get map clause information.
   llvm::OpenMPIRBuilder *ompBuilder = moduleTranslation.getOpenMPBuilder();
   unsigned index = 0;
   for (const auto &mapOp : mapOperands) {
     if (!mapOp.getType().isa<LLVM::LLVMPointerType>()) {
       // TODO: Only LLVMPointerTypes are handled.
       combinedInfo.BasePointers.clear();
       combinedInfo.Pointers.clear();
       combinedInfo.Sizes.clear();
       combinedInfo.Types.clear();
       combinedInfo.Names.clear();
       return;
     }
 
     llvm::Value *mapOpValue = moduleTranslation.lookupValue(mapOp);
     combinedInfo.BasePointers.emplace_back(mapOpValue);
     combinedInfo.Pointers.emplace_back(mapOpValue);
     combinedInfo.Names.emplace_back(
         mlir::LLVM::createMappingInformation(mapOp.getLoc(), *ompBuilder));
-    combinedInfo.Types.emplace_back(llvm::omp::OpenMPOffloadMappingFlags(
-        mapTypes[index].dyn_cast<mlir::IntegerAttr>().getInt()));
+    combinedInfo.Types.emplace_back(
+        llvm::omp::OpenMPOffloadMappingFlags(
+            mapTypes[index].dyn_cast<mlir::IntegerAttr>().getInt()) |
+        (IsTargetParams
+             ? llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_TARGET_PARAM
+             : llvm::omp::OpenMPOffloadMappingFlags::OMP_MAP_NONE));
     combinedInfo.Sizes.emplace_back(
         builder.getInt64(getSizeInBytes(DL, mapOp.getType())));
     index++;
   }
 }
 
 static LogicalResult
 convertOmpTargetData(Operation *op, llvm::IRBuilderBase &builder,
convertOmpTarget(Operation &opInst, llvm::IRBuilderBase &builder,
   }
 
   llvm::TargetRegionEntryInfo entryInfo;
 
   if (!getTargetEntryUniqueInfo(entryInfo, targetOp, parentName))
     return failure();
 
   int32_t defaultValTeams = -1;
-  int32_t defaultValThreads = -1;
+  int32_t defaultValThreads = 0;
+
+  llvm::OpenMPIRBuilder::InsertPointTy allocaIP =
+      findAllocaInsertPoint(builder, moduleTranslation);
+
+  DataLayout DL = DataLayout(opInst.getParentOfType<ModuleOp>());
+  SmallVector<Value> mapOperands = targetOp.getMapOperands();
+  ArrayAttr mapTypes = targetOp.getMapTypes().value();
+
+  llvm::OpenMPIRBuilder::MapInfosTy combinedInfos;
+  auto genMapInfoCB = [&](llvm::OpenMPIRBuilder::InsertPointTy codeGenIP)
+      -> llvm::OpenMPIRBuilder::MapInfosTy & {
+    builder.restoreIP(codeGenIP);
+    genMapInfos(builder, moduleTranslation, DL, combinedInfos, mapOperands,
+                mapTypes, true);
+    return combinedInfos;
+  };
 
   builder.restoreIP(moduleTranslation.getOpenMPBuilder()->createTarget(
-      ompLoc, builder.saveIP(), entryInfo, defaultValTeams, defaultValThreads,
-      inputs, bodyCB));
+      ompLoc, allocaIP, builder.saveIP(), entryInfo, defaultValTeams,
+      defaultValThreads, inputs, genMapInfoCB, bodyCB));
 
   return bodyGenStatus;
 }
 
 static LogicalResult
 convertDeclareTargetAttr(Operation *op,
                          omp::DeclareTargetAttr declareTargetAttr,
                          LLVM::ModuleTranslation &moduleTranslation) {

mlir/test/Target/LLVMIR/omptarget-region-device-llvm.mlir

 // RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
 
 module attributes {omp.is_target_device = true} {
   llvm.func @omp_target_region_() {
     %0 = llvm.mlir.constant(20 : i32) : i32
     %1 = llvm.mlir.constant(10 : i32) : i32
     %2 = llvm.mlir.constant(1 : i64) : i64
     %3 = llvm.alloca %2 x i32 {bindc_name = "a", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEa"} : (i64) -> !llvm.ptr<i32>
     %4 = llvm.mlir.constant(1 : i64) : i64
     %5 = llvm.alloca %4 x i32 {bindc_name = "b", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEb"} : (i64) -> !llvm.ptr<i32>
     %6 = llvm.mlir.constant(1 : i64) : i64
     %7 = llvm.alloca %6 x i32 {bindc_name = "c", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEc"} : (i64) -> !llvm.ptr<i32>
     llvm.store %1, %3 : !llvm.ptr<i32>
     llvm.store %0, %5 : !llvm.ptr<i32>
-    omp.target   {
+    omp.target map((to -> %3 : !llvm.ptr<i32>), (to -> %5 : !llvm.ptr<i32>), (from -> %7 : !llvm.ptr<i32>)) {
       %8 = llvm.load %3 : !llvm.ptr<i32>
       %9 = llvm.load %5 : !llvm.ptr<i32>
       %10 = llvm.add %8, %9  : i32
       llvm.store %10, %7 : !llvm.ptr<i32>
       omp.terminator
     }
     llvm.return
   }

mlir/test/Target/LLVMIR/omptarget-region-llvm.mlir

 // RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
 
 module attributes {omp.is_target_device = false} {
   llvm.func @omp_target_region_() {
     %0 = llvm.mlir.constant(20 : i32) : i32
     %1 = llvm.mlir.constant(10 : i32) : i32
     %2 = llvm.mlir.constant(1 : i64) : i64
     %3 = llvm.alloca %2 x i32 {bindc_name = "a", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEa"} : (i64) -> !llvm.ptr<i32>
     %4 = llvm.mlir.constant(1 : i64) : i64
     %5 = llvm.alloca %4 x i32 {bindc_name = "b", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEb"} : (i64) -> !llvm.ptr<i32>
     %6 = llvm.mlir.constant(1 : i64) : i64
     %7 = llvm.alloca %6 x i32 {bindc_name = "c", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEc"} : (i64) -> !llvm.ptr<i32>
     llvm.store %1, %3 : !llvm.ptr<i32>
     llvm.store %0, %5 : !llvm.ptr<i32>
-    omp.target   {
+    omp.target map((to -> %3 : !llvm.ptr<i32>), (to -> %5 : !llvm.ptr<i32>), (from -> %7 : !llvm.ptr<i32>)) {
       %8 = llvm.load %3 : !llvm.ptr<i32>
       %9 = llvm.load %5 : !llvm.ptr<i32>
       %10 = llvm.add %8, %9  : i32
       llvm.store %10, %7 : !llvm.ptr<i32>
       omp.terminator
     }
     llvm.return
   }

mlir/test/Target/LLVMIR/omptarget-region-parallel-llvm.mlir

 // RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
 
 module attributes {omp.is_target_device = false} {
   llvm.func @omp_target_region_() {
     %0 = llvm.mlir.constant(20 : i32) : i32
     %1 = llvm.mlir.constant(10 : i32) : i32
     %2 = llvm.mlir.constant(1 : i64) : i64
     %3 = llvm.alloca %2 x i32 {bindc_name = "a", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEa"} : (i64) -> !llvm.ptr<i32>
     %4 = llvm.mlir.constant(1 : i64) : i64
     %5 = llvm.alloca %4 x i32 {bindc_name = "b", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEb"} : (i64) -> !llvm.ptr<i32>
     %6 = llvm.mlir.constant(1 : i64) : i64
     %7 = llvm.alloca %6 x i32 {bindc_name = "c", in_type = i32, operand_segment_sizes = array<i32: 0, 0>, uniq_name = "_QFomp_target_regionEc"} : (i64) -> !llvm.ptr<i32>
     llvm.store %1, %3 : !llvm.ptr<i32>
     llvm.store %0, %5 : !llvm.ptr<i32>
-    omp.target {
+    omp.target map((to -> %3 : !llvm.ptr<i32>), (to -> %5 : !llvm.ptr<i32>), (from -> %7 : !llvm.ptr<i32>)) {
       omp.parallel {
         %8 = llvm.load %3 : !llvm.ptr<i32>
         %9 = llvm.load %5 : !llvm.ptr<i32>
         %10 = llvm.add %8, %9  : i32
         llvm.store %10, %7 : !llvm.ptr<i32>
         omp.terminator
         }
       omp.terminator