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     TypeConverter *converter = ConvertToLLVMPattern::getTypeConverter();
56     SmallVector<Type> resTypes;
57     if (failed(converter->convertTypes(curOp->getResultTypes(), resTypes)))
58       return failure();
59     SmallVector<Value> convertedOperands;
60     for (unsigned idx = 0; idx < curOp.getNumVariableOperands(); ++idx) {
61       Value originalVariableOperand = curOp.getVariableOperand(idx);
62       if (!originalVariableOperand)
63         return failure();
64       if (originalVariableOperand.getType().isa<MemRefType>()) {
65         // TODO: Support memref type in variable operands
66         return rewriter.notifyMatchFailure(curOp,
67                                            "memref is not supported yet");
68       }
69       convertedOperands.emplace_back(adaptor.getOperands()[idx]);
70     }
71     rewriter.replaceOpWithNewOp<T>(curOp, resTypes, convertedOperands,
72                                    curOp->getAttrs());
73     return success();
74   }
75 };
76 } // namespace
77 
78 void mlir::configureOpenMPToLLVMConversionLegality(
79     ConversionTarget &target, LLVMTypeConverter &typeConverter) {
80   target.addDynamicallyLegalOp<mlir::omp::ParallelOp, mlir::omp::WsLoopOp,
81                                mlir::omp::MasterOp>(
82       [&](Operation *op) { return typeConverter.isLegal(&op->getRegion(0)); });
83   target
84       .addDynamicallyLegalOp<mlir::omp::AtomicReadOp, mlir::omp::AtomicWriteOp,
85                              mlir::omp::ThreadprivateOp>([&](Operation *op) {
86         return typeConverter.isLegal(op->getOperandTypes());
87       });
88 }
89 
90 void mlir::populateOpenMPToLLVMConversionPatterns(LLVMTypeConverter &converter,
91                                                   RewritePatternSet &patterns) {
92   patterns.add<RegionOpConversion<omp::MasterOp>,
93                RegionOpConversion<omp::ParallelOp>,
94                RegionOpConversion<omp::WsLoopOp>,
95                RegionLessOpConversion<omp::AtomicReadOp>,
96                RegionLessOpConversion<omp::AtomicWriteOp>,
97                RegionLessOpConversion<omp::ThreadprivateOp>>(converter);
98 }
99 
100 namespace {
101 struct ConvertOpenMPToLLVMPass
102     : public ConvertOpenMPToLLVMBase<ConvertOpenMPToLLVMPass> {
103   void runOnOperation() override;
104 };
105 } // namespace
106 
107 void ConvertOpenMPToLLVMPass::runOnOperation() {
108   auto module = getOperation();
109 
110   // Convert to OpenMP operations with LLVM IR dialect
111   RewritePatternSet patterns(&getContext());
112   LLVMTypeConverter converter(&getContext());
113   arith::populateArithmeticToLLVMConversionPatterns(converter, patterns);
114   cf::populateControlFlowToLLVMConversionPatterns(converter, patterns);
115   populateMemRefToLLVMConversionPatterns(converter, patterns);
116   populateFuncToLLVMConversionPatterns(converter, patterns);
117   populateOpenMPToLLVMConversionPatterns(converter, patterns);
118 
119   LLVMConversionTarget target(getContext());
120   target.addLegalOp<omp::TerminatorOp, omp::TaskyieldOp, omp::FlushOp,
121                     omp::BarrierOp, omp::TaskwaitOp>();
122   configureOpenMPToLLVMConversionLegality(target, converter);
123   if (failed(applyPartialConversion(module, target, std::move(patterns))))
124     signalPassFailure();
125 }
126 
127 std::unique_ptr<OperationPass<ModuleOp>> mlir::createConvertOpenMPToLLVMPass() {
128   return std::make_unique<ConvertOpenMPToLLVMPass>();
129 }
130