Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 365 insertions, 163 deletions

diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp b/contrib/llvm/tools/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
index d64f6df..6a6d832 100644
--- a/contrib/llvm/tools/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
+++ b/contrib/llvm/tools/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
@@ -20,53 +20,118 @@
 using namespace clang;
 using namespace CodeGen;
 
-/// \brief Get the GPU warp size.
-llvm::Value *CGOpenMPRuntimeNVPTX::getNVPTXWarpSize(CodeGenFunction &CGF) {
+namespace {
+enum OpenMPRTLFunctionNVPTX {
+  /// \brief Call to void __kmpc_kernel_init(kmp_int32 thread_limit);
+  OMPRTL_NVPTX__kmpc_kernel_init,
+  /// \brief Call to void __kmpc_kernel_deinit();
+  OMPRTL_NVPTX__kmpc_kernel_deinit,
+  /// \brief Call to void __kmpc_kernel_prepare_parallel(void
+  /// *outlined_function);
+  OMPRTL_NVPTX__kmpc_kernel_prepare_parallel,
+  /// \brief Call to bool __kmpc_kernel_parallel(void **outlined_function);
+  OMPRTL_NVPTX__kmpc_kernel_parallel,
+  /// \brief Call to void __kmpc_kernel_end_parallel();
+  OMPRTL_NVPTX__kmpc_kernel_end_parallel,
+  /// Call to void __kmpc_serialized_parallel(ident_t *loc, kmp_int32
+  /// global_tid);
+  OMPRTL_NVPTX__kmpc_serialized_parallel,
+  /// Call to void __kmpc_end_serialized_parallel(ident_t *loc, kmp_int32
+  /// global_tid);
+  OMPRTL_NVPTX__kmpc_end_serialized_parallel,
+};
+
+/// Pre(post)-action for different OpenMP constructs specialized for NVPTX.
+class NVPTXActionTy final : public PrePostActionTy {
+  llvm::Value *EnterCallee;
+  ArrayRef<llvm::Value *> EnterArgs;
+  llvm::Value *ExitCallee;
+  ArrayRef<llvm::Value *> ExitArgs;
+  bool Conditional;
+  llvm::BasicBlock *ContBlock = nullptr;
+
+public:
+  NVPTXActionTy(llvm::Value *EnterCallee, ArrayRef<llvm::Value *> EnterArgs,
+                llvm::Value *ExitCallee, ArrayRef<llvm::Value *> ExitArgs,
+                bool Conditional = false)
+      : EnterCallee(EnterCallee), EnterArgs(EnterArgs), ExitCallee(ExitCallee),
+        ExitArgs(ExitArgs), Conditional(Conditional) {}
+  void Enter(CodeGenFunction &CGF) override {
+    llvm::Value *EnterRes = CGF.EmitRuntimeCall(EnterCallee, EnterArgs);
+    if (Conditional) {
+      llvm::Value *CallBool = CGF.Builder.CreateIsNotNull(EnterRes);
+      auto *ThenBlock = CGF.createBasicBlock("omp_if.then");
+      ContBlock = CGF.createBasicBlock("omp_if.end");
+      // Generate the branch (If-stmt)
+      CGF.Builder.CreateCondBr(CallBool, ThenBlock, ContBlock);
+      CGF.EmitBlock(ThenBlock);
+    }
+  }
+  void Done(CodeGenFunction &CGF) {
+    // Emit the rest of blocks/branches
+    CGF.EmitBranch(ContBlock);
+    CGF.EmitBlock(ContBlock, true);
+  }
+  void Exit(CodeGenFunction &CGF) override {
+    CGF.EmitRuntimeCall(ExitCallee, ExitArgs);
+  }
+};
+} // anonymous namespace
+
+/// Get the GPU warp size.
+static llvm::Value *getNVPTXWarpSize(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   return Bld.CreateCall(
       llvm::Intrinsic::getDeclaration(
-          &CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_warpsize),
+          &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_warpsize),
       llvm::None, "nvptx_warp_size");
 }
 
-/// \brief Get the id of the current thread on the GPU.
-llvm::Value *CGOpenMPRuntimeNVPTX::getNVPTXThreadID(CodeGenFunction &CGF) {
+/// Get the id of the current thread on the GPU.
+static llvm::Value *getNVPTXThreadID(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   return Bld.CreateCall(
       llvm::Intrinsic::getDeclaration(
-          &CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_tid_x),
+          &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_tid_x),
       llvm::None, "nvptx_tid");
 }
 
-// \brief Get the maximum number of threads in a block of the GPU.
-llvm::Value *CGOpenMPRuntimeNVPTX::getNVPTXNumThreads(CodeGenFunction &CGF) {
+/// Get the maximum number of threads in a block of the GPU.
+static llvm::Value *getNVPTXNumThreads(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   return Bld.CreateCall(
       llvm::Intrinsic::getDeclaration(
-          &CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_ntid_x),
+          &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_read_ptx_sreg_ntid_x),
       llvm::None, "nvptx_num_threads");
 }
 
-/// \brief Get barrier to synchronize all threads in a block.
-void CGOpenMPRuntimeNVPTX::getNVPTXCTABarrier(CodeGenFunction &CGF) {
+/// Get barrier to synchronize all threads in a block.
+static void getNVPTXCTABarrier(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   Bld.CreateCall(llvm::Intrinsic::getDeclaration(
-      &CGM.getModule(), llvm::Intrinsic::nvvm_barrier0));
+      &CGF.CGM.getModule(), llvm::Intrinsic::nvvm_barrier0));
 }
 
-// \brief Synchronize all GPU threads in a block.
-void CGOpenMPRuntimeNVPTX::syncCTAThreads(CodeGenFunction &CGF) {
-  getNVPTXCTABarrier(CGF);
+/// Synchronize all GPU threads in a block.
+static void syncCTAThreads(CodeGenFunction &CGF) { getNVPTXCTABarrier(CGF); }
+
+/// Get the value of the thread_limit clause in the teams directive.
+/// The runtime encodes thread_limit in the launch parameter, always starting
+/// thread_limit+warpSize threads per team.
+static llvm::Value *getThreadLimit(CodeGenFunction &CGF) {
+  CGBuilderTy &Bld = CGF.Builder;
+  return Bld.CreateSub(getNVPTXNumThreads(CGF), getNVPTXWarpSize(CGF),
+                       "thread_limit");
 }
 
-/// \brief Get the thread id of the OMP master thread.
+/// Get the thread id of the OMP master thread.
 /// The master thread id is the first thread (lane) of the last warp in the
 /// GPU block.  Warp size is assumed to be some power of 2.
 /// Thread id is 0 indexed.
 /// E.g: If NumThreads is 33, master id is 32.
 ///      If NumThreads is 64, master id is 32.
 ///      If NumThreads is 1024, master id is 992.
-llvm::Value *CGOpenMPRuntimeNVPTX::getMasterThreadID(CodeGenFunction &CGF) {
+static llvm::Value *getMasterThreadID(CodeGenFunction &CGF) {
   CGBuilderTy &Bld = CGF.Builder;
   llvm::Value *NumThreads = getNVPTXNumThreads(CGF);
 
@@ -77,19 +142,6 @@ llvm::Value *CGOpenMPRuntimeNVPTX::getMasterThreadID(CodeGenFunction &CGF) {
                        Bld.CreateNot(Mask), "master_tid");
 }
 
-namespace {
-enum OpenMPRTLFunctionNVPTX {
-  /// \brief Call to void __kmpc_kernel_init(kmp_int32 omp_handle,
-  /// kmp_int32 thread_limit);
-  OMPRTL_NVPTX__kmpc_kernel_init,
-};
-
-// NVPTX Address space
-enum ADDRESS_SPACE {
-  ADDRESS_SPACE_SHARED = 3,
-};
-} // namespace
-
 CGOpenMPRuntimeNVPTX::WorkerFunctionState::WorkerFunctionState(
     CodeGenModule &CGM)
     : WorkerFn(nullptr), CGFI(nullptr) {
@@ -105,35 +157,106 @@ void CGOpenMPRuntimeNVPTX::WorkerFunctionState::createWorkerFunction(
       CGM.getTypes().GetFunctionType(*CGFI), llvm::GlobalValue::InternalLinkage,
       /* placeholder */ "_worker", &CGM.getModule());
   CGM.SetInternalFunctionAttributes(/*D=*/nullptr, WorkerFn, *CGFI);
-  WorkerFn->setLinkage(llvm::GlobalValue::InternalLinkage);
-  WorkerFn->addFnAttr(llvm::Attribute::NoInline);
 }
 
-void CGOpenMPRuntimeNVPTX::initializeEnvironment() {
-  //
-  // Initialize master-worker control state in shared memory.
-  //
+void CGOpenMPRuntimeNVPTX::emitGenericKernel(const OMPExecutableDirective &D,
+                                             StringRef ParentName,
+                                             llvm::Function *&OutlinedFn,
+                                             llvm::Constant *&OutlinedFnID,
+                                             bool IsOffloadEntry,
+                                             const RegionCodeGenTy &CodeGen) {
+  EntryFunctionState EST;
+  WorkerFunctionState WST(CGM);
+  Work.clear();
+
+  // Emit target region as a standalone region.
+  class NVPTXPrePostActionTy : public PrePostActionTy {
+    CGOpenMPRuntimeNVPTX &RT;
+    CGOpenMPRuntimeNVPTX::EntryFunctionState &EST;
+    CGOpenMPRuntimeNVPTX::WorkerFunctionState &WST;
+
+  public:
+    NVPTXPrePostActionTy(CGOpenMPRuntimeNVPTX &RT,
+                         CGOpenMPRuntimeNVPTX::EntryFunctionState &EST,
+                         CGOpenMPRuntimeNVPTX::WorkerFunctionState &WST)
+        : RT(RT), EST(EST), WST(WST) {}
+    void Enter(CodeGenFunction &CGF) override {
+      RT.emitGenericEntryHeader(CGF, EST, WST);
+    }
+    void Exit(CodeGenFunction &CGF) override {
+      RT.emitGenericEntryFooter(CGF, EST);
+    }
+  } Action(*this, EST, WST);
+  CodeGen.setAction(Action);
+  emitTargetOutlinedFunctionHelper(D, ParentName, OutlinedFn, OutlinedFnID,
+                                   IsOffloadEntry, CodeGen);
+
+  // Create the worker function
+  emitWorkerFunction(WST);
+
+  // Now change the name of the worker function to correspond to this target
+  // region's entry function.
+  WST.WorkerFn->setName(OutlinedFn->getName() + "_worker");
+}
+
+// Setup NVPTX threads for master-worker OpenMP scheme.
+void CGOpenMPRuntimeNVPTX::emitGenericEntryHeader(CodeGenFunction &CGF,
+                                                  EntryFunctionState &EST,
+                                                  WorkerFunctionState &WST) {
+  CGBuilderTy &Bld = CGF.Builder;
+
+  llvm::BasicBlock *WorkerBB = CGF.createBasicBlock(".worker");
+  llvm::BasicBlock *MasterCheckBB = CGF.createBasicBlock(".mastercheck");
+  llvm::BasicBlock *MasterBB = CGF.createBasicBlock(".master");
+  EST.ExitBB = CGF.createBasicBlock(".exit");
+
+  auto *IsWorker =
+      Bld.CreateICmpULT(getNVPTXThreadID(CGF), getThreadLimit(CGF));
+  Bld.CreateCondBr(IsWorker, WorkerBB, MasterCheckBB);
 
-  auto DL = CGM.getDataLayout();
-  ActiveWorkers = new llvm::GlobalVariable(
-      CGM.getModule(), CGM.Int32Ty, /*isConstant=*/false,
-      llvm::GlobalValue::CommonLinkage,
-      llvm::Constant::getNullValue(CGM.Int32Ty), "__omp_num_threads", 0,
-      llvm::GlobalVariable::NotThreadLocal, ADDRESS_SPACE_SHARED);
-  ActiveWorkers->setAlignment(DL.getPrefTypeAlignment(CGM.Int32Ty));
-
-  WorkID = new llvm::GlobalVariable(
-      CGM.getModule(), CGM.Int64Ty, /*isConstant=*/false,
-      llvm::GlobalValue::CommonLinkage,
-      llvm::Constant::getNullValue(CGM.Int64Ty), "__tgt_work_id", 0,
-      llvm::GlobalVariable::NotThreadLocal, ADDRESS_SPACE_SHARED);
-  WorkID->setAlignment(DL.getPrefTypeAlignment(CGM.Int64Ty));
+  CGF.EmitBlock(WorkerBB);
+  CGF.EmitCallOrInvoke(WST.WorkerFn, llvm::None);
+  CGF.EmitBranch(EST.ExitBB);
+
+  CGF.EmitBlock(MasterCheckBB);
+  auto *IsMaster =
+      Bld.CreateICmpEQ(getNVPTXThreadID(CGF), getMasterThreadID(CGF));
+  Bld.CreateCondBr(IsMaster, MasterBB, EST.ExitBB);
+
+  CGF.EmitBlock(MasterBB);
+  // First action in sequential region:
+  // Initialize the state of the OpenMP runtime library on the GPU.
+  llvm::Value *Args[] = {getThreadLimit(CGF)};
+  CGF.EmitRuntimeCall(
+      createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_init), Args);
+}
+
+void CGOpenMPRuntimeNVPTX::emitGenericEntryFooter(CodeGenFunction &CGF,
+                                                  EntryFunctionState &EST) {
+  if (!EST.ExitBB)
+    EST.ExitBB = CGF.createBasicBlock(".exit");
+
+  llvm::BasicBlock *TerminateBB = CGF.createBasicBlock(".termination.notifier");
+  CGF.EmitBranch(TerminateBB);
+
+  CGF.EmitBlock(TerminateBB);
+  // Signal termination condition.
+  CGF.EmitRuntimeCall(
+      createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_deinit), None);
+  // Barrier to terminate worker threads.
+  syncCTAThreads(CGF);
+  // Master thread jumps to exit point.
+  CGF.EmitBranch(EST.ExitBB);
+
+  CGF.EmitBlock(EST.ExitBB);
+  EST.ExitBB = nullptr;
 }
 
 void CGOpenMPRuntimeNVPTX::emitWorkerFunction(WorkerFunctionState &WST) {
   auto &Ctx = CGM.getContext();
 
   CodeGenFunction CGF(CGM, /*suppressNewContext=*/true);
+  CGF.disableDebugInfo();
   CGF.StartFunction(GlobalDecl(), Ctx.VoidTy, WST.WorkerFn, *WST.CGFI, {});
   emitWorkerLoop(CGF, WST);
   CGF.FinishFunction();
@@ -165,28 +288,68 @@ void CGOpenMPRuntimeNVPTX::emitWorkerLoop(CodeGenFunction &CGF,
   CGF.EmitBlock(AwaitBB);
   // Wait for parallel work
   syncCTAThreads(CGF);
+
+  Address WorkFn =
+      CGF.CreateDefaultAlignTempAlloca(CGF.Int8PtrTy, /*Name=*/"work_fn");
+  Address ExecStatus =
+      CGF.CreateDefaultAlignTempAlloca(CGF.Int8Ty, /*Name=*/"exec_status");
+  CGF.InitTempAlloca(ExecStatus, Bld.getInt8(/*C=*/0));
+  CGF.InitTempAlloca(WorkFn, llvm::Constant::getNullValue(CGF.Int8PtrTy));
+
+  llvm::Value *Args[] = {WorkFn.getPointer()};
+  llvm::Value *Ret = CGF.EmitRuntimeCall(
+      createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_parallel), Args);
+  Bld.CreateStore(Bld.CreateZExt(Ret, CGF.Int8Ty), ExecStatus);
+
   // On termination condition (workid == 0), exit loop.
-  llvm::Value *ShouldTerminate = Bld.CreateICmpEQ(
-      Bld.CreateAlignedLoad(WorkID, WorkID->getAlignment()),
-      llvm::Constant::getNullValue(WorkID->getType()->getElementType()),
-      "should_terminate");
+  llvm::Value *ShouldTerminate =
+      Bld.CreateIsNull(Bld.CreateLoad(WorkFn), "should_terminate");
   Bld.CreateCondBr(ShouldTerminate, ExitBB, SelectWorkersBB);
 
   // Activate requested workers.
   CGF.EmitBlock(SelectWorkersBB);
-  llvm::Value *ThreadID = getNVPTXThreadID(CGF);
-  llvm::Value *ActiveThread = Bld.CreateICmpSLT(
-      ThreadID,
-      Bld.CreateAlignedLoad(ActiveWorkers, ActiveWorkers->getAlignment()),
-      "active_thread");
-  Bld.CreateCondBr(ActiveThread, ExecuteBB, BarrierBB);
+  llvm::Value *IsActive =
+      Bld.CreateIsNotNull(Bld.CreateLoad(ExecStatus), "is_active");
+  Bld.CreateCondBr(IsActive, ExecuteBB, BarrierBB);
 
   // Signal start of parallel region.
   CGF.EmitBlock(ExecuteBB);
-  // TODO: Add parallel work.
+
+  // Process work items: outlined parallel functions.
+  for (auto *W : Work) {
+    // Try to match this outlined function.
+    auto *ID = Bld.CreatePointerBitCastOrAddrSpaceCast(W, CGM.Int8PtrTy);
+
+    llvm::Value *WorkFnMatch =
+        Bld.CreateICmpEQ(Bld.CreateLoad(WorkFn), ID, "work_match");
+
+    llvm::BasicBlock *ExecuteFNBB = CGF.createBasicBlock(".execute.fn");
+    llvm::BasicBlock *CheckNextBB = CGF.createBasicBlock(".check.next");
+    Bld.CreateCondBr(WorkFnMatch, ExecuteFNBB, CheckNextBB);
+
+    // Execute this outlined function.
+    CGF.EmitBlock(ExecuteFNBB);
+
+    // Insert call to work function.
+    // FIXME: Pass arguments to outlined function from master thread.
+    auto *Fn = cast<llvm::Function>(W);
+    Address ZeroAddr =
+        CGF.CreateDefaultAlignTempAlloca(CGF.Int32Ty, /*Name=*/".zero.addr");
+    CGF.InitTempAlloca(ZeroAddr, CGF.Builder.getInt32(/*C=*/0));
+    llvm::Value *FnArgs[] = {ZeroAddr.getPointer(), ZeroAddr.getPointer()};
+    CGF.EmitCallOrInvoke(Fn, FnArgs);
+
+    // Go to end of parallel region.
+    CGF.EmitBranch(TerminateBB);
+
+    CGF.EmitBlock(CheckNextBB);
+  }
 
   // Signal end of parallel region.
   CGF.EmitBlock(TerminateBB);
+  CGF.EmitRuntimeCall(
+      createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_end_parallel),
+      llvm::None);
   CGF.EmitBranch(BarrierBB);
 
   // All active and inactive workers wait at a barrier after parallel region.
@@ -199,68 +362,6 @@ void CGOpenMPRuntimeNVPTX::emitWorkerLoop(CodeGenFunction &CGF,
   CGF.EmitBlock(ExitBB);
 }
 
-// Setup NVPTX threads for master-worker OpenMP scheme.
-void CGOpenMPRuntimeNVPTX::emitEntryHeader(CodeGenFunction &CGF,
-                                           EntryFunctionState &EST,
-                                           WorkerFunctionState &WST) {
-  CGBuilderTy &Bld = CGF.Builder;
-
-  // Get the master thread id.
-  llvm::Value *MasterID = getMasterThreadID(CGF);
-  // Current thread's identifier.
-  llvm::Value *ThreadID = getNVPTXThreadID(CGF);
-
-  // Setup BBs in entry function.
-  llvm::BasicBlock *WorkerCheckBB = CGF.createBasicBlock(".check.for.worker");
-  llvm::BasicBlock *WorkerBB = CGF.createBasicBlock(".worker");
-  llvm::BasicBlock *MasterBB = CGF.createBasicBlock(".master");
-  EST.ExitBB = CGF.createBasicBlock(".exit");
-
-  // The head (master thread) marches on while its body of companion threads in
-  // the warp go to sleep.
-  llvm::Value *ShouldDie =
-      Bld.CreateICmpUGT(ThreadID, MasterID, "excess_in_master_warp");
-  Bld.CreateCondBr(ShouldDie, EST.ExitBB, WorkerCheckBB);
-
-  // Select worker threads...
-  CGF.EmitBlock(WorkerCheckBB);
-  llvm::Value *IsWorker = Bld.CreateICmpULT(ThreadID, MasterID, "is_worker");
-  Bld.CreateCondBr(IsWorker, WorkerBB, MasterBB);
-
-  // ... and send to worker loop, awaiting parallel invocation.
-  CGF.EmitBlock(WorkerBB);
-  CGF.EmitCallOrInvoke(WST.WorkerFn, llvm::None);
-  CGF.EmitBranch(EST.ExitBB);
-
-  // Only master thread executes subsequent serial code.
-  CGF.EmitBlock(MasterBB);
-
-  // First action in sequential region:
-  // Initialize the state of the OpenMP runtime library on the GPU.
-  llvm::Value *Args[] = {Bld.getInt32(/*OmpHandle=*/0), getNVPTXThreadID(CGF)};
-  CGF.EmitRuntimeCall(createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_init),
-                      Args);
-}
-
-void CGOpenMPRuntimeNVPTX::emitEntryFooter(CodeGenFunction &CGF,
-                                           EntryFunctionState &EST) {
-  CGBuilderTy &Bld = CGF.Builder;
-  llvm::BasicBlock *TerminateBB = CGF.createBasicBlock(".termination.notifier");
-  CGF.EmitBranch(TerminateBB);
-
-  CGF.EmitBlock(TerminateBB);
-  // Signal termination condition.
-  Bld.CreateAlignedStore(
-      llvm::Constant::getNullValue(WorkID->getType()->getElementType()), WorkID,
-      WorkID->getAlignment());
-  // Barrier to terminate worker threads.
-  syncCTAThreads(CGF);
-  // Master thread jumps to exit point.
-  CGF.EmitBranch(EST.ExitBB);
-
-  CGF.EmitBlock(EST.ExitBB);
-}
-
 /// \brief Returns specified OpenMP runtime function for the current OpenMP
 /// implementation.  Specialized for the NVPTX device.
 /// \param Function OpenMP runtime function.
@@ -270,21 +371,70 @@ CGOpenMPRuntimeNVPTX::createNVPTXRuntimeFunction(unsigned Function) {
   llvm::Constant *RTLFn = nullptr;
   switch (static_cast<OpenMPRTLFunctionNVPTX>(Function)) {
   case OMPRTL_NVPTX__kmpc_kernel_init: {
-    // Build void __kmpc_kernel_init(kmp_int32 omp_handle,
-    // kmp_int32 thread_limit);
-    llvm::Type *TypeParams[] = {CGM.Int32Ty, CGM.Int32Ty};
+    // Build void __kmpc_kernel_init(kmp_int32 thread_limit);
+    llvm::Type *TypeParams[] = {CGM.Int32Ty};
     llvm::FunctionType *FnTy =
         llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
     RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_init");
     break;
   }
+  case OMPRTL_NVPTX__kmpc_kernel_deinit: {
+    // Build void __kmpc_kernel_deinit();
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.VoidTy, llvm::None, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_deinit");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_kernel_prepare_parallel: {
+    /// Build void __kmpc_kernel_prepare_parallel(
+    /// void *outlined_function);
+    llvm::Type *TypeParams[] = {CGM.Int8PtrTy};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_prepare_parallel");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_kernel_parallel: {
+    /// Build bool __kmpc_kernel_parallel(void **outlined_function);
+    llvm::Type *TypeParams[] = {CGM.Int8PtrPtrTy};
+    llvm::Type *RetTy = CGM.getTypes().ConvertType(CGM.getContext().BoolTy);
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(RetTy, TypeParams, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_parallel");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_kernel_end_parallel: {
+    /// Build void __kmpc_kernel_end_parallel();
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.VoidTy, llvm::None, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_kernel_end_parallel");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_serialized_parallel: {
+    // Build void __kmpc_serialized_parallel(ident_t *loc, kmp_int32
+    // global_tid);
+    llvm::Type *TypeParams[] = {getIdentTyPointerTy(), CGM.Int32Ty};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_serialized_parallel");
+    break;
+  }
+  case OMPRTL_NVPTX__kmpc_end_serialized_parallel: {
+    // Build void __kmpc_end_serialized_parallel(ident_t *loc, kmp_int32
+    // global_tid);
+    llvm::Type *TypeParams[] = {getIdentTyPointerTy(), CGM.Int32Ty};
+    llvm::FunctionType *FnTy =
+        llvm::FunctionType::get(CGM.VoidTy, TypeParams, /*isVarArg*/ false);
+    RTLFn = CGM.CreateRuntimeFunction(FnTy, "__kmpc_end_serialized_parallel");
+    break;
+  }
   }
   return RTLFn;
 }
 
 void CGOpenMPRuntimeNVPTX::createOffloadEntry(llvm::Constant *ID,
                                               llvm::Constant *Addr,
-                                              uint64_t Size) {
+                                              uint64_t Size, int32_t) {
   auto *F = dyn_cast<llvm::Function>(Addr);
   // TODO: Add support for global variables on the device after declare target
   // support.
@@ -313,44 +463,14 @@ void CGOpenMPRuntimeNVPTX::emitTargetOutlinedFunction(
 
   assert(!ParentName.empty() && "Invalid target region parent name!");
 
-  EntryFunctionState EST;
-  WorkerFunctionState WST(CGM);
-
-  // Emit target region as a standalone region.
-  class NVPTXPrePostActionTy : public PrePostActionTy {
-    CGOpenMPRuntimeNVPTX &RT;
-    CGOpenMPRuntimeNVPTX::EntryFunctionState &EST;
-    CGOpenMPRuntimeNVPTX::WorkerFunctionState &WST;
-
-  public:
-    NVPTXPrePostActionTy(CGOpenMPRuntimeNVPTX &RT,
-                         CGOpenMPRuntimeNVPTX::EntryFunctionState &EST,
-                         CGOpenMPRuntimeNVPTX::WorkerFunctionState &WST)
-        : RT(RT), EST(EST), WST(WST) {}
-    void Enter(CodeGenFunction &CGF) override {
-      RT.emitEntryHeader(CGF, EST, WST);
-    }
-    void Exit(CodeGenFunction &CGF) override { RT.emitEntryFooter(CGF, EST); }
-  } Action(*this, EST, WST);
-  CodeGen.setAction(Action);
-  emitTargetOutlinedFunctionHelper(D, ParentName, OutlinedFn, OutlinedFnID,
-                                   IsOffloadEntry, CodeGen);
-
-  // Create the worker function
-  emitWorkerFunction(WST);
-
-  // Now change the name of the worker function to correspond to this target
-  // region's entry function.
-  WST.WorkerFn->setName(OutlinedFn->getName() + "_worker");
+  emitGenericKernel(D, ParentName, OutlinedFn, OutlinedFnID, IsOffloadEntry,
+                    CodeGen);
 }
 
 CGOpenMPRuntimeNVPTX::CGOpenMPRuntimeNVPTX(CodeGenModule &CGM)
-    : CGOpenMPRuntime(CGM), ActiveWorkers(nullptr), WorkID(nullptr) {
+    : CGOpenMPRuntime(CGM) {
   if (!CGM.getLangOpts().OpenMPIsDevice)
     llvm_unreachable("OpenMP NVPTX can only handle device code.");
-
-  // Called once per module during initialization.
-  initializeEnvironment();
 }
 
 void CGOpenMPRuntimeNVPTX::emitNumTeamsClause(CodeGenFunction &CGF,
@@ -368,10 +488,14 @@ llvm::Value *CGOpenMPRuntimeNVPTX::emitParallelOrTeamsOutlinedFunction(
         CGOpenMPRuntime::emitParallelOrTeamsOutlinedFunction(
             D, ThreadIDVar, InnermostKind, CodeGen);
     OutlinedFun = cast<llvm::Function>(OutlinedFunVal);
+    OutlinedFun->removeFnAttr(llvm::Attribute::NoInline);
     OutlinedFun->addFnAttr(llvm::Attribute::AlwaysInline);
-  } else
-    llvm_unreachable("parallel directive is not yet supported for nvptx "
-                     "backend.");
+  } else {
+    llvm::Value *OutlinedFunVal =
+        CGOpenMPRuntime::emitParallelOrTeamsOutlinedFunction(
+            D, ThreadIDVar, InnermostKind, CodeGen);
+    OutlinedFun = cast<llvm::Function>(OutlinedFunVal);
+  }
 
   return OutlinedFun;
 }
@@ -394,3 +518,81 @@ void CGOpenMPRuntimeNVPTX::emitTeamsCall(CodeGenFunction &CGF,
   OutlinedFnArgs.append(CapturedVars.begin(), CapturedVars.end());
   CGF.EmitCallOrInvoke(OutlinedFn, OutlinedFnArgs);
 }
+
+void CGOpenMPRuntimeNVPTX::emitParallelCall(
+    CodeGenFunction &CGF, SourceLocation Loc, llvm::Value *OutlinedFn,
+    ArrayRef<llvm::Value *> CapturedVars, const Expr *IfCond) {
+  if (!CGF.HaveInsertPoint())
+    return;
+
+  emitGenericParallelCall(CGF, Loc, OutlinedFn, CapturedVars, IfCond);
+}
+
+void CGOpenMPRuntimeNVPTX::emitGenericParallelCall(
+    CodeGenFunction &CGF, SourceLocation Loc, llvm::Value *OutlinedFn,
+    ArrayRef<llvm::Value *> CapturedVars, const Expr *IfCond) {
+  llvm::Function *Fn = cast<llvm::Function>(OutlinedFn);
+
+  auto &&L0ParallelGen = [this, Fn, &CapturedVars](CodeGenFunction &CGF,
+                                                   PrePostActionTy &) {
+    CGBuilderTy &Bld = CGF.Builder;
+
+    // Prepare for parallel region. Indicate the outlined function.
+    llvm::Value *Args[] = {Bld.CreateBitOrPointerCast(Fn, CGM.Int8PtrTy)};
+    CGF.EmitRuntimeCall(
+        createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_kernel_prepare_parallel),
+        Args);
+
+    // Activate workers. This barrier is used by the master to signal
+    // work for the workers.
+    syncCTAThreads(CGF);
+
+    // OpenMP [2.5, Parallel Construct, p.49]
+    // There is an implied barrier at the end of a parallel region. After the
+    // end of a parallel region, only the master thread of the team resumes
+    // execution of the enclosing task region.
+    //
+    // The master waits at this barrier until all workers are done.
+    syncCTAThreads(CGF);
+
+    // Remember for post-processing in worker loop.
+    Work.push_back(Fn);
+  };
+
+  auto *RTLoc = emitUpdateLocation(CGF, Loc);
+  auto *ThreadID = getThreadID(CGF, Loc);
+  llvm::Value *Args[] = {RTLoc, ThreadID};
+
+  auto &&SeqGen = [this, Fn, &CapturedVars, &Args](CodeGenFunction &CGF,
+                                                   PrePostActionTy &) {
+    auto &&CodeGen = [this, Fn, &CapturedVars, &Args](CodeGenFunction &CGF,
+                                                      PrePostActionTy &Action) {
+      Action.Enter(CGF);
+
+      llvm::SmallVector<llvm::Value *, 16> OutlinedFnArgs;
+      OutlinedFnArgs.push_back(
+          llvm::ConstantPointerNull::get(CGM.Int32Ty->getPointerTo()));
+      OutlinedFnArgs.push_back(
+          llvm::ConstantPointerNull::get(CGM.Int32Ty->getPointerTo()));
+      OutlinedFnArgs.append(CapturedVars.begin(), CapturedVars.end());
+      CGF.EmitCallOrInvoke(Fn, OutlinedFnArgs);
+    };
+
+    RegionCodeGenTy RCG(CodeGen);
+    NVPTXActionTy Action(
+        createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_serialized_parallel),
+        Args,
+        createNVPTXRuntimeFunction(OMPRTL_NVPTX__kmpc_end_serialized_parallel),
+        Args);
+    RCG.setAction(Action);
+    RCG(CGF);
+  };
+
+  if (IfCond)
+    emitOMPIfClause(CGF, IfCond, L0ParallelGen, SeqGen);
+  else {
+    CodeGenFunction::RunCleanupsScope Scope(CGF);
+    RegionCodeGenTy ThenRCG(L0ParallelGen);
+    ThenRCG(CGF);
+  }
+}