422b84a771
Add a rewriter for DIExpressions & use it to run legalization patterns before exporting to llvm (because LLVM dialect allows DI Expressions that may not be valid in LLVM IR). The rewriter driver works similarly to the existing mlir rewriter drivers, except it operates on lists of DIExpressionElemAttr (i.e. DIExpressionAttr). Each rewrite pattern transforms a range of DIExpressionElemAttr into a new list of DIExpressionElemAttr. In addition, this PR sets up a place to add legalization patterns that are broadly applicable internally to the LLVM dialect, and they will always be applied prior to export. This PR adds one pattern for merging fragment operators. --------- Co-authored-by: Tobias Gysi <tobias.gysi@nextsilicon.com>
62 lines
2.1 KiB
C++
62 lines
2.1 KiB
C++
//===- DIExpressionLegalization.cpp - DIExpression Legalization Patterns --===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "mlir/Dialect/LLVMIR/Transforms/DIExpressionLegalization.h"
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#include "llvm/BinaryFormat/Dwarf.h"
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using namespace mlir;
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using namespace LLVM;
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//===----------------------------------------------------------------------===//
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// MergeFragments
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//===----------------------------------------------------------------------===//
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MergeFragments::OpIterT MergeFragments::match(OpIterRange operators) const {
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OpIterT it = operators.begin();
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if (it == operators.end() ||
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it->getOpcode() != llvm::dwarf::DW_OP_LLVM_fragment)
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return operators.begin();
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++it;
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if (it == operators.end() ||
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it->getOpcode() != llvm::dwarf::DW_OP_LLVM_fragment)
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return operators.begin();
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return ++it;
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}
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SmallVector<MergeFragments::OperatorT>
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MergeFragments::replace(OpIterRange operators) const {
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OpIterT it = operators.begin();
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OperatorT first = *(it++);
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OperatorT second = *it;
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// Add offsets & select the size of the earlier operator (the one closer to
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// the IR value).
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uint64_t offset = first.getArguments()[0] + second.getArguments()[0];
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uint64_t size = first.getArguments()[1];
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OperatorT newOp = OperatorT::get(
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first.getContext(), llvm::dwarf::DW_OP_LLVM_fragment, {offset, size});
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return SmallVector<OperatorT>{newOp};
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}
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//===----------------------------------------------------------------------===//
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// Runner
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//===----------------------------------------------------------------------===//
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void mlir::LLVM::legalizeDIExpressionsRecursively(Operation *op) {
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LLVM::DIExpressionRewriter rewriter;
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rewriter.addPattern(std::make_unique<MergeFragments>());
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AttrTypeReplacer replacer;
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replacer.addReplacement([&rewriter](LLVM::DIExpressionAttr expr) {
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return rewriter.simplify(expr);
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});
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replacer.recursivelyReplaceElementsIn(op);
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}
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