[CIR][OpenMP] Taskwait, Taskyield and Barrier implementation (#555)

This PR is the final fix for issue #499.

clang/lib/CIR/CodeGen/CIRGenFunction.h

@@ -30,6 +30,7 @@
 
 #include "mlir/IR/TypeRange.h"
 #include "mlir/IR/Value.h"
+#include "mlir/Support/LogicalResult.h"
 
 namespace clang {
 class Expr;
@@ -993,6 +994,10 @@ class CIRGenFunction : public CIRGenTypeCache {
 
   // OpenMP gen functions:
   mlir::LogicalResult buildOMPParallelDirective(const OMPParallelDirective &S);
+  mlir::LogicalResult buildOMPTaskwaitDirective(const OMPTaskwaitDirective &S);
+  mlir::LogicalResult
+  buildOMPTaskyieldDirective(const OMPTaskyieldDirective &S);
+  mlir::LogicalResult buildOMPBarrierDirective(const OMPBarrierDirective &S);
 
   LValue buildOpaqueValueLValue(const OpaqueValueExpr *e);
 

clang/lib/CIR/CodeGen/CIRGenOpenMPRuntime.cpp

@@ -52,3 +52,55 @@ bool CIRGenOpenMPRuntime::emitTargetGlobal(clang::GlobalDecl &GD) {
   assert(!UnimplementedFeature::openMPRuntime());
   return false;
 }
+
+void CIRGenOpenMPRuntime::emitTaskWaitCall(CIRGenBuilderTy &builder,
+                                           CIRGenFunction &CGF,
+                                           mlir::Location Loc,
+                                           const OMPTaskDataTy &Data) {
+
+  if (!CGF.HaveInsertPoint())
+    return;
+
+  if (CGF.CGM.getLangOpts().OpenMPIRBuilder && Data.Dependences.empty()) {
+    // TODO: Need to support taskwait with dependences in the OpenMPIRBuilder.
+    // TODO(cir): This could change in the near future when OpenMP 5.0 gets
+    // supported by MLIR
+    builder.create<mlir::omp::TaskwaitOp>(Loc);
+  } else {
+    llvm_unreachable("NYI");
+  }
+  assert(!UnimplementedFeature::openMPRegionInfo());
+}
+
+void CIRGenOpenMPRuntime::emitBarrierCall(CIRGenBuilderTy &builder,
+                                          CIRGenFunction &CGF,
+                                          mlir::Location Loc) {
+
+  assert(!UnimplementedFeature::openMPRegionInfo());
+
+  if (CGF.CGM.getLangOpts().OpenMPIRBuilder) {
+    builder.create<mlir::omp::BarrierOp>(Loc);
+    return;
+  }
+
+  if (!CGF.HaveInsertPoint())
+    return;
+
+  llvm_unreachable("NYI");
+}
+
+void CIRGenOpenMPRuntime::emitTaskyieldCall(CIRGenBuilderTy &builder,
+                                            CIRGenFunction &CGF,
+                                            mlir::Location Loc) {
+
+  if (!CGF.HaveInsertPoint())
+    return;
+
+  if (CGF.CGM.getLangOpts().OpenMPIRBuilder) {
+    builder.create<mlir::omp::TaskyieldOp>(Loc);
+  } else {
+    llvm_unreachable("NYI");
+  }
+
+  assert(!UnimplementedFeature::openMPRegionInfo());
+}

clang/lib/CIR/CodeGen/CIRGenOpenMPRuntime.h

@@ -13,9 +13,21 @@
 #ifndef LLVM_CLANG_LIB_CIR_CODEGEN_CIRGENOPENMPRUNTIME_H
 #define LLVM_CLANG_LIB_CIR_CODEGEN_CIRGENOPENMPRUNTIME_H
 
+#include "CIRGenBuilder.h"
 #include "CIRGenValue.h"
+
+#include "clang/AST/Redeclarable.h"
+#include "clang/Basic/OpenMPKinds.h"
 #include "clang/CIR/Dialect/IR/CIRDialect.h"
 
+#include "llvm/Support/ErrorHandling.h"
+
+#include "mlir/Dialect/OpenMP/OpenMPDialect.h"
+#include "mlir/IR/Dialect.h"
+#include "mlir/IR/Location.h"
+
+#include "UnimplementedFeatureGuarding.h"
+
 namespace clang {
 class Decl;
 class Expr;
@@ -27,6 +39,20 @@ namespace cir {
 class CIRGenModule;
 class CIRGenFunction;
 
+struct OMPTaskDataTy final {
+  struct DependData {
+    clang::OpenMPDependClauseKind DepKind = clang::OMPC_DEPEND_unknown;
+    const clang::Expr *IteratorExpr = nullptr;
+    llvm::SmallVector<const clang::Expr *, 4> DepExprs;
+    explicit DependData() = default;
+    DependData(clang::OpenMPDependClauseKind DepKind,
+               const clang::Expr *IteratorExpr)
+        : DepKind(DepKind), IteratorExpr(IteratorExpr) {}
+  };
+  llvm::SmallVector<DependData, 4> Dependences;
+  bool HasNowaitClause = false;
+};
+
 class CIRGenOpenMPRuntime {
 public:
   explicit CIRGenOpenMPRuntime(CIRGenModule &CGM);
@@ -69,6 +95,16 @@ class CIRGenOpenMPRuntime {
   /// \param GD Global to scan.
   virtual bool emitTargetGlobal(clang::GlobalDecl &D);
 
+  /// Emit code for 'taskwait' directive
+  virtual void emitTaskWaitCall(CIRGenBuilderTy &builder, CIRGenFunction &CGF,
+                                mlir::Location Loc, const OMPTaskDataTy &Data);
+
+  virtual void emitBarrierCall(CIRGenBuilderTy &builder, CIRGenFunction &CGF,
+                               mlir::Location Loc);
+
+  virtual void emitTaskyieldCall(CIRGenBuilderTy &builder, CIRGenFunction &CGF,
+                                 mlir::Location Loc);
+
 protected:
   CIRGenModule &CGM;
 };

clang/lib/CIR/CodeGen/CIRGenStmt.cpp

@@ -180,6 +180,12 @@ mlir::LogicalResult CIRGenFunction::buildStmt(const Stmt *S,
   // OMP directives:
   case Stmt::OMPParallelDirectiveClass:
     return buildOMPParallelDirective(cast<OMPParallelDirective>(*S));
+  case Stmt::OMPTaskwaitDirectiveClass:
+    return buildOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
+  case Stmt::OMPTaskyieldDirectiveClass:
+    return buildOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
+  case Stmt::OMPBarrierDirectiveClass:
+    return buildOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
   // Unsupported AST nodes:
   case Stmt::CapturedStmtClass:
   case Stmt::ObjCAtTryStmtClass:
@@ -205,9 +211,6 @@ mlir::LogicalResult CIRGenFunction::buildStmt(const Stmt *S,
   case Stmt::OMPParallelMasterDirectiveClass:
   case Stmt::OMPParallelSectionsDirectiveClass:
   case Stmt::OMPTaskDirectiveClass:
-  case Stmt::OMPTaskyieldDirectiveClass:
-  case Stmt::OMPBarrierDirectiveClass:
-  case Stmt::OMPTaskwaitDirectiveClass:
   case Stmt::OMPTaskgroupDirectiveClass:
   case Stmt::OMPFlushDirectiveClass:
   case Stmt::OMPDepobjDirectiveClass:

clang/lib/CIR/CodeGen/CIRGenStmtOpenMP.cpp

@@ -9,15 +9,63 @@
 // This contains code to emit OpenMP Stmt nodes as MLIR code.
 //
 //===----------------------------------------------------------------------===//
+#include "clang/AST/ASTFwd.h"
+#include "clang/AST/StmtIterator.h"
+#include "clang/AST/StmtOpenMP.h"
+#include "clang/Basic/OpenMPKinds.h"
 
 #include "CIRGenFunction.h"
 #include "CIRGenOpenMPRuntime.h"
+
+#include "mlir/Dialect/Arith/IR/Arith.h"
 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
+#include "mlir/IR/Attributes.h"
+#include "mlir/IR/Builders.h"
+#include "mlir/IR/BuiltinAttributeInterfaces.h"
+#include "mlir/IR/BuiltinAttributes.h"
+#include "mlir/IR/BuiltinTypes.h"
+#include "mlir/IR/Location.h"
+#include "mlir/IR/Value.h"
+#include "mlir/Support/LogicalResult.h"
 
 using namespace cir;
 using namespace clang;
 using namespace mlir::omp;
 
+static void buildDependences(const OMPExecutableDirective &S,
+                             OMPTaskDataTy &Data) {
+
+  // First look for 'omp_all_memory' and add this first.
+  bool OmpAllMemory = false;
+  if (llvm::any_of(
+          S.getClausesOfKind<OMPDependClause>(), [](const OMPDependClause *C) {
+            return C->getDependencyKind() == OMPC_DEPEND_outallmemory ||
+                   C->getDependencyKind() == OMPC_DEPEND_inoutallmemory;
+          })) {
+    OmpAllMemory = true;
+    // Since both OMPC_DEPEND_outallmemory and OMPC_DEPEND_inoutallmemory are
+    // equivalent to the runtime, always use OMPC_DEPEND_outallmemory to
+    // simplify.
+    OMPTaskDataTy::DependData &DD =
+        Data.Dependences.emplace_back(OMPC_DEPEND_outallmemory,
+                                      /*IteratorExpr=*/nullptr);
+    // Add a nullptr Expr to simplify the codegen in emitDependData.
+    DD.DepExprs.push_back(nullptr);
+  }
+  // Add remaining dependences skipping any 'out' or 'inout' if they are
+  // overridden by 'omp_all_memory'.
+  for (const auto *C : S.getClausesOfKind<OMPDependClause>()) {
+    OpenMPDependClauseKind Kind = C->getDependencyKind();
+    if (Kind == OMPC_DEPEND_outallmemory || Kind == OMPC_DEPEND_inoutallmemory)
+      continue;
+    if (OmpAllMemory && (Kind == OMPC_DEPEND_out || Kind == OMPC_DEPEND_inout))
+      continue;
+    OMPTaskDataTy::DependData &DD =
+        Data.Dependences.emplace_back(C->getDependencyKind(), C->getModifier());
+    DD.DepExprs.append(C->varlist_begin(), C->varlist_end());
+  }
+}
+
 mlir::LogicalResult
 CIRGenFunction::buildOMPParallelDirective(const OMPParallelDirective &S) {
   mlir::LogicalResult res = mlir::success();
@@ -43,3 +91,31 @@ CIRGenFunction::buildOMPParallelDirective(const OMPParallelDirective &S) {
   builder.create<TerminatorOp>(getLoc(S.getSourceRange().getEnd()));
   return res;
 }
+
+mlir::LogicalResult
+CIRGenFunction::buildOMPTaskwaitDirective(const OMPTaskwaitDirective &S) {
+  mlir::LogicalResult res = mlir::success();
+  OMPTaskDataTy Data;
+  buildDependences(S, Data);
+  Data.HasNowaitClause = S.hasClausesOfKind<OMPNowaitClause>();
+  CGM.getOpenMPRuntime().emitTaskWaitCall(builder, *this,
+                                          getLoc(S.getSourceRange()), Data);
+  return res;
+}
+mlir::LogicalResult
+CIRGenFunction::buildOMPTaskyieldDirective(const OMPTaskyieldDirective &S) {
+  mlir::LogicalResult res = mlir::success();
+  // Creation of an omp.taskyield operation
+  CGM.getOpenMPRuntime().emitTaskyieldCall(builder, *this,
+                                           getLoc(S.getSourceRange()));
+  return res;
+}
+
+mlir::LogicalResult
+CIRGenFunction::buildOMPBarrierDirective(const OMPBarrierDirective &S) {
+  mlir::LogicalResult res = mlir::success();
+  // Creation of an omp.barrier operation
+  CGM.getOpenMPRuntime().emitBarrierCall(builder, *this,
+                                         getLoc(S.getSourceRange()));
+  return res;
+}

clang/lib/CIR/CodeGen/UnimplementedFeatureGuarding.h

@@ -135,6 +135,7 @@ struct UnimplementedFeature {
   static bool CUDA() { return false; }
   static bool openMP() { return false; }
   static bool openMPRuntime() { return false; }
+  static bool openMPRegionInfo() { return false; }
   static bool openMPTarget() { return false; }
   static bool isVarArg() { return false; }
   static bool setNonGC() { return false; }

clang/test/CIR/CodeGen/OpenMP/barrier.cpp

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fopenmp-enable-irbuilder -fopenmp -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s
+
+// CHECK: cir.func
+void omp_barrier_1(){
+// CHECK: omp.barrier
+  #pragma omp barrier
+}

clang/test/CIR/CodeGen/OpenMP/taskwait.cpp

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fopenmp-enable-irbuilder -fopenmp -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s
+
+// CHECK: cir.func
+void omp_taskwait_1(){
+// CHECK: omp.taskwait
+  #pragma omp taskwait
+}

clang/test/CIR/CodeGen/OpenMP/taskyield.cpp

@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fopenmp-enable-irbuilder -fopenmp -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s
+
+// CHECK: cir.func
+void omp_taskyield_1(){
+// CHECK: omp.taskyield
+  #pragma omp taskyield
+}

clang/test/CIR/Lowering/OpenMP/barrier.cir

@@ -0,0 +1,15 @@
+
+// RUN: cir-translate %s -cir-to-llvmir | FileCheck %s
+
+
+module {
+  cir.func @omp_barrier_1() {
+    omp.barrier
+    cir.return
+  }
+}
+
+// CHECK: define void @omp_barrier_1()
+// CHECK: call i32 @__kmpc_global_thread_num(ptr {{.*}})
+// CHECK: call void @__kmpc_barrier(ptr {{.*}}, i32 {{.*}})
+// CHECK: ret void

clang/test/CIR/Lowering/OpenMP/taskwait.cir

@@ -0,0 +1,14 @@
+// RUN: cir-translate %s -cir-to-llvmir | FileCheck %s
+
+
+module {
+  cir.func @omp_taskwait_1() {
+    omp.taskwait
+    cir.return
+  }
+}
+
+// CHECK: define void @omp_taskwait_1()
+// CHECK: call i32 @__kmpc_global_thread_num(ptr {{.*}})
+// CHECK: call i32 @__kmpc_omp_taskwait(ptr {{.*}}, i32 {{.*}})
+// CHECK: ret void

clang/test/CIR/Lowering/OpenMP/taskyield.cir

@@ -0,0 +1,14 @@
+// RUN: cir-translate %s -cir-to-llvmir | FileCheck %s
+
+
+module {
+  cir.func @omp_taskyield_1() {
+    omp.taskyield
+    cir.return
+  }
+}
+
+// CHECK: define void @omp_taskyield_1()
+// CHECK: call i32 @__kmpc_global_thread_num(ptr {{.*}})
+// CHECK: call i32 @__kmpc_omp_taskyield(ptr {{.*}}, i32 {{.*}}, i32 {{.*}})
+// CHECK: ret void