[OpenMP] Use the OpenMP-IR-Builder

This is a follow up patch to use the OpenMP-IR-Builder, as discussed on
the mailing list ([1] and later) and at the US Dev Meeting'19.

[1] http://lists.flang-compiler.org/pipermail/flang-dev_lists.flang-compiler.org/2019-May/000197.html

Reviewers: kiranchandramohan, ABataev, RaviNarayanaswamy, gtbercea, grokos, sdmitriev, JonChesterfield, hfinkel, fghanim

Subscribers: ppenzin, penzn, llvm-commits, cfe-commits, jfb, guansong, bollu, hiraditya, mgorny

Tags: #clang

Differential Revision: https://reviews.llvm.org/D69922

6 files changed, 43 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index fda8dbe14db..e3e9bd4284c 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -23,6 +23,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SetOperations.h"
 #include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/Value.h"
@@ -3481,6 +3482,29 @@ void CGOpenMPRuntime::getDefaultScheduleAndChunk(
 void CGOpenMPRuntime::emitBarrierCall(CodeGenFunction &CGF, SourceLocation Loc,
                                       OpenMPDirectiveKind Kind, bool EmitChecks,
                                       bool ForceSimpleCall) {
+  // Check if we should use the OMPBuilder
+  auto *OMPRegionInfo =
+      dyn_cast_or_null<CGOpenMPRegionInfo>(CGF.CapturedStmtInfo);
+  llvm::OpenMPIRBuilder *OMPBuilder = CGF.CGM.getOpenMPIRBuilder();
+  if (OMPBuilder) {
+    // TODO: Move cancelation point handling into the IRBuilder.
+    if (EmitChecks && !ForceSimpleCall && OMPRegionInfo &&
+        OMPRegionInfo->hasCancel() && CGF.Builder.GetInsertBlock()) {
+      CGBuilderTy::InsertPointGuard IPG(CGF.Builder);
+      llvm::BasicBlock *ExitBB = CGF.createBasicBlock(
+          ".cancel.exit", CGF.Builder.GetInsertBlock()->getParent());
+      OMPBuilder->setCancellationBlock(ExitBB);
+      CGF.Builder.SetInsertPoint(ExitBB);
+      CodeGenFunction::JumpDest CancelDestination =
+          CGF.getOMPCancelDestination(OMPRegionInfo->getDirectiveKind());
+      CGF.EmitBranchThroughCleanup(CancelDestination);
+    }
+    auto IP = OMPBuilder->CreateBarrier(CGF.Builder, Kind, ForceSimpleCall,
+                                        EmitChecks);
+    CGF.Builder.restoreIP(IP);
+    return;
+  }
+
   if (!CGF.HaveInsertPoint())
     return;
   // Build call __kmpc_cancel_barrier(loc, thread_id);
@@ -3490,8 +3514,7 @@ void CGOpenMPRuntime::emitBarrierCall(CodeGenFunction &CGF, SourceLocation Loc,
   // thread_id);
   llvm::Value *Args[] = {emitUpdateLocation(CGF, Loc, Flags),
                          getThreadID(CGF, Loc)};
-  if (auto *OMPRegionInfo =
-          dyn_cast_or_null<CGOpenMPRegionInfo>(CGF.CapturedStmtInfo)) {
+  if (OMPRegionInfo) {
     if (!ForceSimpleCall && OMPRegionInfo->hasCancel()) {
       llvm::Value *Result = CGF.EmitRuntimeCall(
           createRuntimeFunction(OMPRTL__kmpc_cancel_barrier), Args);
diff --git a/clang/lib/CodeGen/CMakeLists.txt b/clang/lib/CodeGen/CMakeLists.txt
index 6d1f33b8924..a3980637c59 100644
--- a/clang/lib/CodeGen/CMakeLists.txt
+++ b/clang/lib/CodeGen/CMakeLists.txt
@@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS
   Core
   Coroutines
   Coverage
+  FrontendOpenMP
   IPO
   IRReader
   AggressiveInstCombine
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 3805eae17b3..1fc2beb12ed 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -47,6 +47,7 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Intrinsics.h"
@@ -218,6 +219,14 @@ void CodeGenModule::createOpenMPRuntime() {
       OpenMPRuntime.reset(new CGOpenMPRuntime(*this));
     break;
   }
+
+  // The OpenMP-IR-Builder should eventually replace the above runtime codegens
+  // but we are not there yet so they both reside in CGModule for now and the
+  // OpenMP-IR-Builder is opt-in only.
+  if (LangOpts.OpenMPIRBuilder) {
+    OMPBuilder.reset(new llvm::OpenMPIRBuilder(TheModule));
+    OMPBuilder->initialize();
+  }
 }
 
 void CodeGenModule::createCUDARuntime() {
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 8fd8cbcf5a3..9bf1c5ef610 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -44,6 +44,7 @@ class GlobalValue;
 class DataLayout;
 class FunctionType;
 class LLVMContext;
+class OpenMPIRBuilder;
 class IndexedInstrProfReader;
 }
 
@@ -321,6 +322,7 @@ private:
   std::unique_ptr<CGObjCRuntime> ObjCRuntime;
   std::unique_ptr<CGOpenCLRuntime> OpenCLRuntime;
   std::unique_ptr<CGOpenMPRuntime> OpenMPRuntime;
+  std::unique_ptr<llvm::OpenMPIRBuilder> OMPBuilder;
   std::unique_ptr<CGCUDARuntime> CUDARuntime;
   std::unique_ptr<CGDebugInfo> DebugInfo;
   std::unique_ptr<ObjCEntrypoints> ObjCData;
@@ -587,6 +589,9 @@ public:
     return *OpenMPRuntime;
   }
 
+  /// Return a pointer to the configured OpenMPIRBuilder, if any.
+  llvm::OpenMPIRBuilder *getOpenMPIRBuilder() { return OMPBuilder.get(); }
+
   /// Return a reference to the configured CUDA runtime.
   CGCUDARuntime &getCUDARuntime() {
     assert(CUDARuntime != nullptr);
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 4960f3e4248..c00d5d07bcf 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4955,6 +4955,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
         CmdArgs.push_back("-fnoopenmp-use-tls");
       Args.AddLastArg(CmdArgs, options::OPT_fopenmp_simd,
                       options::OPT_fno_openmp_simd);
+      Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_enable_irbuilder);
       Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_version_EQ);
       Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_cuda_number_of_sm_EQ);
       Args.AddAllArgs(CmdArgs, options::OPT_fopenmp_cuda_blocks_per_sm_EQ);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 1af2bdab61e..0e39560052d 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3014,6 +3014,8 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
       Opts.OpenMP && !Args.hasArg(options::OPT_fnoopenmp_use_tls);
   Opts.OpenMPIsDevice =
       Opts.OpenMP && Args.hasArg(options::OPT_fopenmp_is_device);
+  Opts.OpenMPIRBuilder =
+      Opts.OpenMP && Args.hasArg(options::OPT_fopenmp_enable_irbuilder);
   bool IsTargetSpecified =
       Opts.OpenMPIsDevice || Args.hasArg(options::OPT_fopenmp_targets_EQ);