[mlir] Use dialect interfaces to translate OpenMP dialect to LLVM IR

Migrate the translation of the OpenMP dialect operations to LLVM IR to the new
dialect-based mechanism.

Depends On D96503

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D96504

Author: ftynse

mlir/include/mlir/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.h

@@ -0,0 +1,37 @@
+//===- OpenMPToLLVMIRTranslation.h - OpenMP Dialect to LLVM IR --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the dialect interface for translating the OpenMP dialect
+// to LLVM IR.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_TARGET_LLVMIR_DIALECT_OPENMP_OPENMPTOLLVMIRTRANSLATION_H
+#define MLIR_TARGET_LLVMIR_DIALECT_OPENMP_OPENMPTOLLVMIRTRANSLATION_H
+
+#include "mlir/Target/LLVMIR/LLVMTranslationInterface.h"
+
+namespace mlir {
+
+/// Implementation of the dialect interface that converts operations beloning to
+/// the OpenMP dialect to LLVM IR.
+class OpenMPDialectLLVMIRTranslationInterface
+    : public LLVMTranslationDialectInterface {
+public:
+  using LLVMTranslationDialectInterface::LLVMTranslationDialectInterface;
+
+  /// Translates the given operation to LLVM IR using the provided IR builder
+  /// and saving the state in `moduleTranslation`.
+  LogicalResult
+  convertOperation(Operation *op, llvm::IRBuilderBase &builder,
+                   LLVM::ModuleTranslation &moduleTranslation) const final;
+};
+
+} // namespace mlir
+
+#endif // MLIR_TARGET_LLVMIR_DIALECT_OPENMP_OPENMPTOLLVMIRTRANSLATION_H

mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h

@@ -22,6 +22,7 @@
 #include "mlir/Target/LLVMIR/LLVMTranslationInterface.h"
 #include "mlir/Target/LLVMIR/TypeTranslation.h"
 
+#include "llvm/ADT/SetVector.h"
 #include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Function.h"
@@ -160,6 +161,29 @@ class ModuleTranslation {
     return globalsMapping.lookup(op);
   }
 
+  /// Returns the OpenMP IR builder associated with the LLVM IR module being
+  /// constructed.
+  llvm::OpenMPIRBuilder *getOpenMPBuilder() {
+    if (!ompBuilder) {
+      ompBuilder = std::make_unique<llvm::OpenMPIRBuilder>(*llvmModule);
+      ompBuilder->initialize();
+    }
+    return ompBuilder.get();
+  }
+
+  /// Translates the given location.
+  const llvm::DILocation *translateLoc(Location loc, llvm::DILocalScope *scope);
+
+  /// Translates the contents of the given block to LLVM IR using this
+  /// translator. The LLVM IR basic block corresponding to the given block is
+  /// expected to exist in the mapping of this translator. Uses `builder` to
+  /// translate the IR, leaving it at the end of the block. If `ignoreArguments`
+  /// is set, does not produce PHI nodes for the block arguments. Otherwise, the
+  /// PHI nodes are constructed for block arguments but are _not_ connected to
+  /// the predecessors that may not exist yet.
+  LogicalResult convertBlock(Block &bb, bool ignoreArguments,
+                             llvm::IRBuilder<> &builder);
+
 protected:
   /// Translate the given MLIR module expressed in MLIR LLVM IR dialect into an
   /// LLVM IR module. The MLIR LLVM IR dialect holds a pointer to an
@@ -170,19 +194,6 @@ class ModuleTranslation {
 
   virtual LogicalResult convertOperation(Operation &op,
                                          llvm::IRBuilder<> &builder);
-  virtual LogicalResult convertOmpOperation(Operation &op,
-                                            llvm::IRBuilder<> &builder);
-  virtual LogicalResult convertOmpParallel(Operation &op,
-                                           llvm::IRBuilder<> &builder);
-  virtual LogicalResult convertOmpMaster(Operation &op,
-                                         llvm::IRBuilder<> &builder);
-  void convertOmpOpRegions(Region &region, StringRef blockName,
-                           llvm::BasicBlock &sourceBlock,
-                           llvm::BasicBlock &continuationBlock,
-                           llvm::IRBuilder<> &builder,
-                           LogicalResult &bodyGenStatus);
-  virtual LogicalResult convertOmpWsLoop(Operation &opInst,
-                                         llvm::IRBuilder<> &builder);
 
   static std::unique_ptr<llvm::Module>
   prepareLLVMModule(Operation *m, llvm::LLVMContext &llvmContext,
@@ -196,8 +207,6 @@ class ModuleTranslation {
   LogicalResult convertFunctions();
   LogicalResult convertGlobals();
   LogicalResult convertOneFunction(LLVMFuncOp func);
-  LogicalResult convertBlock(Block &bb, bool ignoreArguments,
-                             llvm::IRBuilder<> &builder);
 
   /// Original and translated module.
   Operation *mlirModule;
@@ -232,6 +241,16 @@ class ModuleTranslation {
   DenseMap<Operation *, llvm::Instruction *> branchMapping;
 };
 
+namespace detail {
+/// For all blocks in the region that were converted to LLVM IR using the given
+/// ModuleTranslation, connect the PHI nodes of the corresponding LLVM IR blocks
+/// to the results of preceding blocks.
+void connectPHINodes(Region &region, const ModuleTranslation &state);
+
+/// Get a topologically sorted list of blocks of the given region.
+llvm::SetVector<Block *> getTopologicallySortedBlocks(Region &region);
+} // namespace detail
+
 } // namespace LLVM
 } // namespace mlir
 

mlir/lib/Target/CMakeLists.txt

@@ -57,6 +57,7 @@ add_mlir_translation_library(MLIRTargetLLVMIR
 
   LINK_LIBS PUBLIC
   MLIRLLVMToLLVMIRTranslation
+  MLIROpenMPToLLVMIRTranslation
   MLIRTargetLLVMIRModuleTranslation
   )
 

mlir/lib/Target/LLVMIR/ConvertToLLVMIR.cpp

@@ -14,6 +14,7 @@
 
 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
 #include "mlir/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.h"
+#include "mlir/Target/LLVMIR/Dialect/OpenMP/OpenMPToLLVMIRTranslation.h"
 #include "mlir/Target/LLVMIR/ModuleTranslation.h"
 #include "mlir/Translation.h"
 
@@ -70,6 +71,8 @@ void registerToLLVMIRTranslation() {
       },
       [](DialectRegistry &registry) {
         registry.insert<omp::OpenMPDialect>();
+        registry.addDialectInterface<omp::OpenMPDialect,
+                                     OpenMPDialectLLVMIRTranslationInterface>();
         registerLLVMDialectTranslation(registry);
       });
 }

mlir/lib/Target/LLVMIR/Dialect/CMakeLists.txt

@@ -1 +1,2 @@
 add_subdirectory(LLVMIR)
+add_subdirectory(OpenMP)

mlir/lib/Target/LLVMIR/Dialect/OpenMP/CMakeLists.txt

@@ -0,0 +1,13 @@
+add_mlir_translation_library(MLIROpenMPToLLVMIRTranslation
+  OpenMPToLLVMIRTranslation.cpp
+
+  LINK_COMPONENTS
+  Core
+
+  LINK_LIBS PUBLIC
+  MLIRIR
+  MLIRLLVMIR
+  MLIROpenMP
+  MLIRSupport
+  MLIRTargetLLVMIRModuleTranslation
+  )