llvm/llvm/lib/Analysis/PhiValues.cpp

//===- PhiValues.cpp - Phi Value Analysis ---------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/PhiValues.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/Instructions.h"
#include "llvm/InitializePasses.h"

usingnamespacellvm;

void PhiValues::PhiValuesCallbackVH::deleted() { … }

void PhiValues::PhiValuesCallbackVH::allUsesReplacedWith(Value *) { … }

bool PhiValues::invalidate(Function &, const PreservedAnalyses &PA,
                           FunctionAnalysisManager::Invalidator &) { … }

// The goal here is to find all of the non-phi values reachable from this phi,
// and to do the same for all of the phis reachable from this phi, as doing so
// is necessary anyway in order to get the values for this phi. We do this using
// Tarjan's algorithm with Nuutila's improvements to find the strongly connected
// components of the phi graph rooted in this phi:
//  * All phis in a strongly connected component will have the same reachable
//    non-phi values. The SCC may not be the maximal subgraph for that set of
//    reachable values, but finding out that isn't really necessary (it would
//    only reduce the amount of memory needed to store the values).
//  * Tarjan's algorithm completes components in a bottom-up manner, i.e. it
//    never completes a component before the components reachable from it have
//    been completed. This means that when we complete a component we have
//    everything we need to collect the values reachable from that component.
//  * We collect both the non-phi values reachable from each SCC, as that's what
//    we're ultimately interested in, and all of the reachable values, i.e.
//    including phis, as that makes invalidateValue easier.
void PhiValues::processPhi(const PHINode *Phi,
                           SmallVectorImpl<const PHINode *> &Stack) { … }

const PhiValues::ValueSet &PhiValues::getValuesForPhi(const PHINode *PN) { … }

void PhiValues::invalidateValue(const Value *V) { … }

void PhiValues::releaseMemory() { … }

void PhiValues::print(raw_ostream &OS) const { … }

AnalysisKey PhiValuesAnalysis::Key;
PhiValues PhiValuesAnalysis::run(Function &F, FunctionAnalysisManager &) { … }

PreservedAnalyses PhiValuesPrinterPass::run(Function &F,
                                            FunctionAnalysisManager &AM) { … }

PhiValuesWrapperPass::PhiValuesWrapperPass() : … { … }

bool PhiValuesWrapperPass::runOnFunction(Function &F) { … }

void PhiValuesWrapperPass::releaseMemory() { … }

void PhiValuesWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { … }

char PhiValuesWrapperPass::ID = …;

INITIALIZE_PASS(…)