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/StandardToLLVM/ConvertStandardToLLVM.h"
13 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
14 #include "mlir/Dialect/OpenMP/OpenMPDialect.h"
15 
16 using namespace mlir;
17 
18 namespace {
19 /// A pattern that converts the region arguments in a single-region OpenMP
20 /// operation to the LLVM dialect. The body of the region is not modified and is
21 /// expected to either be processed by the conversion infrastructure or already
22 /// contain ops compatible with LLVM dialect types.
23 template <typename OpType>
24 struct RegionOpConversion : public ConvertToLLVMPattern {
25   explicit RegionOpConversion(MLIRContext *context,
26                               LLVMTypeConverter &typeConverter)
27       : ConvertToLLVMPattern(OpType::getOperationName(), context,
28                              typeConverter) {}
29 
30   LogicalResult
31   matchAndRewrite(Operation *op, ArrayRef<Value> operands,
32                   ConversionPatternRewriter &rewriter) const override {
33     auto curOp = cast<OpType>(op);
34     auto newOp = rewriter.create<OpType>(curOp.getLoc(), TypeRange(), operands,
35                                          curOp.getAttrs());
36     rewriter.inlineRegionBefore(curOp.region(), newOp.region(),
37                                 newOp.region().end());
38     if (failed(rewriter.convertRegionTypes(&newOp.region(), *typeConverter)))
39       return failure();
40 
41     rewriter.eraseOp(op);
42     return success();
43   }
44 };
45 } // namespace
46 
47 void mlir::populateOpenMPToLLVMConversionPatterns(
48     MLIRContext *context, LLVMTypeConverter &converter,
49     OwningRewritePatternList &patterns) {
50   patterns.insert<RegionOpConversion<omp::ParallelOp>,
51                   RegionOpConversion<omp::WsLoopOp>>(context, converter);
52 }
53 
54 namespace {
55 struct ConvertOpenMPToLLVMPass
56     : public ConvertOpenMPToLLVMBase<ConvertOpenMPToLLVMPass> {
57   void runOnOperation() override;
58 };
59 } // namespace
60 
61 void ConvertOpenMPToLLVMPass::runOnOperation() {
62   auto module = getOperation();
63   MLIRContext *context = &getContext();
64 
65   // Convert to OpenMP operations with LLVM IR dialect
66   OwningRewritePatternList patterns;
67   LLVMTypeConverter converter(&getContext());
68   populateStdToLLVMConversionPatterns(converter, patterns);
69   populateOpenMPToLLVMConversionPatterns(context, converter, patterns);
70 
71   LLVMConversionTarget target(getContext());
72   target.addDynamicallyLegalOp<omp::ParallelOp, omp::WsLoopOp>(
73       [&](Operation *op) { return converter.isLegal(&op->getRegion(0)); });
74   target.addLegalOp<omp::TerminatorOp, omp::TaskyieldOp, omp::FlushOp,
75                     omp::BarrierOp, omp::TaskwaitOp>();
76   if (failed(applyPartialConversion(module, target, std::move(patterns))))
77     signalPassFailure();
78 }
79 
80 std::unique_ptr<OperationPass<ModuleOp>> mlir::createConvertOpenMPToLLVMPass() {
81   return std::make_unique<ConvertOpenMPToLLVMPass>();
82 }
83