forked from OSchip/llvm-project
59 lines
2.2 KiB
C++
59 lines
2.2 KiB
C++
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//- CFLAndersAliasAnalysis.cpp - Unification-based Alias Analysis ---*- C++-*-//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements a CFL-based, summary-based alias analysis algorithm. It
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// differs from CFLSteensAliasAnalysis in its inclusion-based nature while
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// CFLSteensAliasAnalysis is unification-based. This pass has worse performance
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// than CFLSteensAliasAnalysis (the worst case complexity of
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// CFLAndersAliasAnalysis is cubic, while the worst case complexity of
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// CFLSteensAliasAnalysis is almost linear), but it is able to yield more
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// precise analysis result. The precision of this analysis is roughly the same
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// as that of an one level context-sensitive Andersen's algorithm.
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//
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//===----------------------------------------------------------------------===//
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// N.B. AliasAnalysis as a whole is phrased as a FunctionPass at the moment, and
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// CFLAndersAA is interprocedural. This is *technically* A Bad Thing, because
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// FunctionPasses are only allowed to inspect the Function that they're being
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// run on. Realistically, this likely isn't a problem until we allow
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// FunctionPasses to run concurrently.
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#include "llvm/Analysis/CFLAndersAliasAnalysis.h"
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#include "llvm/Pass.h"
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using namespace llvm;
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#define DEBUG_TYPE "cfl-anders-aa"
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CFLAndersAAResult::CFLAndersAAResult() = default;
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char CFLAndersAA::PassID;
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CFLAndersAAResult CFLAndersAA::run(Function &F, AnalysisManager<Function> &AM) {
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return CFLAndersAAResult();
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}
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char CFLAndersAAWrapperPass::ID = 0;
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INITIALIZE_PASS(CFLAndersAAWrapperPass, "cfl-anders-aa",
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"Inclusion-Based CFL Alias Analysis", false, true)
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ImmutablePass *llvm::createCFLAndersAAWrapperPass() {
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return new CFLAndersAAWrapperPass();
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}
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CFLAndersAAWrapperPass::CFLAndersAAWrapperPass() : ImmutablePass(ID) {
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initializeCFLAndersAAWrapperPassPass(*PassRegistry::getPassRegistry());
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}
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void CFLAndersAAWrapperPass::initializePass() {}
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void CFLAndersAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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}
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