9a277af2d4
This revision adds support for generating utilities for passes such as options/statistics/etc. that can be inferred from the tablegen definition. This removes additional boilerplate from the pass, and also makes it easier to remove the reliance on the pass registry to provide certain things(e.g. the pass argument). Differential Revision: https://reviews.llvm.org/D76659
74 lines
2.7 KiB
C++
74 lines
2.7 KiB
C++
//===- LegalizeForExport.cpp - Prepare for translation to LLVM IR ---------===//
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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/LegalizeForExport.h"
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#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
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#include "mlir/IR/Block.h"
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#include "mlir/IR/Builders.h"
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#include "mlir/IR/Module.h"
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#include "mlir/Pass/Pass.h"
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using namespace mlir;
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static void ensureDistinctSuccessors(Block &bb) {
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auto *terminator = bb.getTerminator();
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// Find repeated successors with arguments.
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llvm::SmallDenseMap<Block *, SmallVector<int, 4>> successorPositions;
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for (int i = 0, e = terminator->getNumSuccessors(); i < e; ++i) {
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Block *successor = terminator->getSuccessor(i);
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// Blocks with no arguments are safe even if they appear multiple times
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// because they don't need PHI nodes.
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if (successor->getNumArguments() == 0)
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continue;
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successorPositions[successor].push_back(i);
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}
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// If a successor appears for the second or more time in the terminator,
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// create a new dummy block that unconditionally branches to the original
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// destination, and retarget the terminator to branch to this new block.
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// There is no need to pass arguments to the dummy block because it will be
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// dominated by the original block and can therefore use any values defined in
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// the original block.
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OpBuilder builder(terminator->getContext());
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for (const auto &successor : successorPositions) {
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// Start from the second occurrence of a block in the successor list.
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for (int position : llvm::drop_begin(successor.second, 1)) {
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Block *dummyBlock = builder.createBlock(bb.getParent());
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terminator->setSuccessor(dummyBlock, position);
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dummyBlock->addArguments(successor.first->getArgumentTypes());
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builder.create<LLVM::BrOp>(terminator->getLoc(),
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dummyBlock->getArguments(), successor.first);
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}
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}
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}
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void mlir::LLVM::ensureDistinctSuccessors(Operation *op) {
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op->walk([](LLVMFuncOp f) {
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for (auto &bb : f.getBlocks()) {
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::ensureDistinctSuccessors(bb);
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}
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});
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}
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namespace {
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struct LegalizeForExportPass : public OperationPass<LegalizeForExportPass> {
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/// Include the generated pass utilities.
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#define GEN_PASS_LLVMLegalizeForExport
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#include "mlir/Dialect/LLVMIR/Transforms/Passes.h.inc"
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void runOnOperation() override {
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LLVM::ensureDistinctSuccessors(getOperation());
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}
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};
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} // end namespace
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std::unique_ptr<Pass> LLVM::createLegalizeForExportPass() {
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return std::make_unique<LegalizeForExportPass>();
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}
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