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//===- MachinePostDominators.cpp -Machine Post Dominator Calculation ------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements simple dominator construction algorithms for finding
// post dominators on machine functions.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachinePostDominators.h"
#include "llvm/InitializePasses.h"
using namespace llvm;
namespace llvm {
template class DominatorTreeBase<MachineBasicBlock, true>; // PostDomTreeBase
extern bool VerifyMachineDomInfo;
} // namespace llvm
char MachinePostDominatorTree::ID = 0;
//declare initializeMachinePostDominatorTreePass
INITIALIZE_PASS(MachinePostDominatorTree, "machinepostdomtree",
"MachinePostDominator Tree Construction", true, true)
MachinePostDominatorTree::MachinePostDominatorTree()
: MachineFunctionPass(ID), PDT(nullptr) {
initializeMachinePostDominatorTreePass(*PassRegistry::getPassRegistry());
}
FunctionPass *MachinePostDominatorTree::createMachinePostDominatorTreePass() {
return new MachinePostDominatorTree();
}
bool MachinePostDominatorTree::runOnMachineFunction(MachineFunction &F) {
PDT = std::make_unique<PostDomTreeT>();
PDT->recalculate(F);
return false;
}
void MachinePostDominatorTree::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
}
MachineBasicBlock *MachinePostDominatorTree::findNearestCommonDominator(
ArrayRef<MachineBasicBlock *> Blocks) const {
assert(!Blocks.empty());
MachineBasicBlock *NCD = Blocks.front();
for (MachineBasicBlock *BB : Blocks.drop_front()) {
NCD = PDT->findNearestCommonDominator(NCD, BB);
// Stop when the root is reached.
if (PDT->isVirtualRoot(PDT->getNode(NCD)))
return nullptr;
}
return NCD;
}
void MachinePostDominatorTree::verifyAnalysis() const {
if (PDT && VerifyMachineDomInfo)
if (!PDT->verify(PostDomTreeT::VerificationLevel::Basic)) {
errs() << "MachinePostDominatorTree verification failed\n";
abort();
}
}
void MachinePostDominatorTree::print(llvm::raw_ostream &OS,
const Module *M) const {
PDT->print(OS);
}