1 //===- OpenMPToLLVM.cpp - conversion from OpenMP to LLVM dialect ----------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "mlir/Conversion/OpenMPToLLVM/ConvertOpenMPToLLVM.h"
10 
11 #include "../PassDetail.h"
12 #include "mlir/Conversion/ArithmeticToLLVM/ArithmeticToLLVM.h"
13 #include "mlir/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.h"
14 #include "mlir/Conversion/FuncToLLVM/ConvertFuncToLLVM.h"
15 #include "mlir/Conversion/FuncToLLVM/ConvertFuncToLLVMPass.h"
16 #include "mlir/Conversion/LLVMCommon/ConversionTarget.h"
17 #include "mlir/Conversion/LLVMCommon/Pattern.h"
18 #include "mlir/Conversion/MemRefToLLVM/MemRefToLLVM.h"
19 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
20 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
21 
22 using namespace mlir;
23 
24 namespace {
25 /// A pattern that converts the region arguments in a single-region OpenMP
26 /// operation to the LLVM dialect. The body of the region is not modified and is
27 /// expected to either be processed by the conversion infrastructure or already
28 /// contain ops compatible with LLVM dialect types.
29 template <typename OpType>
30 struct RegionOpConversion : public ConvertOpToLLVMPattern<OpType> {
31   using ConvertOpToLLVMPattern<OpType>::ConvertOpToLLVMPattern;
32 
33   LogicalResult
34   matchAndRewrite(OpType curOp, typename OpType::Adaptor adaptor,
35                   ConversionPatternRewriter &rewriter) const override {
36     auto newOp = rewriter.create<OpType>(
37         curOp.getLoc(), TypeRange(), adaptor.getOperands(), curOp->getAttrs());
38     rewriter.inlineRegionBefore(curOp.region(), newOp.region(),
39                                 newOp.region().end());
40     if (failed(rewriter.convertRegionTypes(&newOp.region(),
41                                            *this->getTypeConverter())))
42       return failure();
43 
44     rewriter.eraseOp(curOp);
45     return success();
46   }
47 };
48 
49 template <typename T>
50 struct RegionLessOpConversion : public ConvertOpToLLVMPattern<T> {
51   using ConvertOpToLLVMPattern<T>::ConvertOpToLLVMPattern;
52   LogicalResult
53   matchAndRewrite(T curOp, typename T::Adaptor adaptor,
54                   ConversionPatternRewriter &rewriter) const override {
55     rewriter.replaceOpWithNewOp<T>(curOp, TypeRange(), adaptor.getOperands(),
56                                    curOp->getAttrs());
57     return success();
58   }
59 };
60 } // namespace
61 
62 void mlir::configureOpenMPToLLVMConversionLegality(
63     ConversionTarget &target, LLVMTypeConverter &typeConverter) {
64   target.addDynamicallyLegalOp<mlir::omp::ParallelOp, mlir::omp::WsLoopOp,
65                                mlir::omp::MasterOp>(
66       [&](Operation *op) { return typeConverter.isLegal(&op->getRegion(0)); });
67   target
68       .addDynamicallyLegalOp<mlir::omp::AtomicReadOp, mlir::omp::AtomicWriteOp>(
69           [&](Operation *op) {
70             return typeConverter.isLegal(op->getOperandTypes());
71           });
72 }
73 
74 void mlir::populateOpenMPToLLVMConversionPatterns(LLVMTypeConverter &converter,
75                                                   RewritePatternSet &patterns) {
76   patterns.add<RegionOpConversion<omp::MasterOp>,
77                RegionOpConversion<omp::ParallelOp>,
78                RegionOpConversion<omp::WsLoopOp>,
79                RegionLessOpConversion<omp::AtomicReadOp>,
80                RegionLessOpConversion<omp::AtomicWriteOp>>(converter);
81 }
82 
83 namespace {
84 struct ConvertOpenMPToLLVMPass
85     : public ConvertOpenMPToLLVMBase<ConvertOpenMPToLLVMPass> {
86   void runOnOperation() override;
87 };
88 } // namespace
89 
90 void ConvertOpenMPToLLVMPass::runOnOperation() {
91   auto module = getOperation();
92 
93   // Convert to OpenMP operations with LLVM IR dialect
94   RewritePatternSet patterns(&getContext());
95   LLVMTypeConverter converter(&getContext());
96   arith::populateArithmeticToLLVMConversionPatterns(converter, patterns);
97   cf::populateControlFlowToLLVMConversionPatterns(converter, patterns);
98   populateMemRefToLLVMConversionPatterns(converter, patterns);
99   populateFuncToLLVMConversionPatterns(converter, patterns);
100   populateOpenMPToLLVMConversionPatterns(converter, patterns);
101 
102   LLVMConversionTarget target(getContext());
103   target.addLegalOp<omp::TerminatorOp, omp::TaskyieldOp, omp::FlushOp,
104                     omp::BarrierOp, omp::TaskwaitOp>();
105   configureOpenMPToLLVMConversionLegality(target, converter);
106   if (failed(applyPartialConversion(module, target, std::move(patterns))))
107     signalPassFailure();
108 }
109 
110 std::unique_ptr<OperationPass<ModuleOp>> mlir::createConvertOpenMPToLLVMPass() {
111   return std::make_unique<ConvertOpenMPToLLVMPass>();
112 }
113