145 lines
4.6 KiB
C++
145 lines
4.6 KiB
C++
//==- CFLSteensAliasAnalysis.h - Unification-based Alias Analysis -*- C++-*-==//
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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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/// \file
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/// This is the interface for LLVM's unification-based alias analysis
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/// implemented with CFL graph reachability.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_CFLSTEENSALIASANALYSIS_H
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#define LLVM_ANALYSIS_CFLSTEENSALIASANALYSIS_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/Analysis/CFLAliasAnalysisUtils.h"
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#include "llvm/Analysis/MemoryLocation.h"
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#include "llvm/IR/PassManager.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/Casting.h"
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#include <forward_list>
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#include <memory>
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namespace llvm {
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class Function;
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class TargetLibraryInfo;
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namespace cflaa {
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struct AliasSummary;
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} // end namespace cflaa
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class CFLSteensAAResult : public AAResultBase<CFLSteensAAResult> {
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friend AAResultBase<CFLSteensAAResult>;
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class FunctionInfo;
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public:
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explicit CFLSteensAAResult(
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std::function<const TargetLibraryInfo &(Function &)> GetTLI);
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CFLSteensAAResult(CFLSteensAAResult &&Arg);
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~CFLSteensAAResult();
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/// Handle invalidation events from the new pass manager.
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///
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/// By definition, this result is stateless and so remains valid.
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bool invalidate(Function &, const PreservedAnalyses &,
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FunctionAnalysisManager::Invalidator &) {
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return false;
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}
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/// Inserts the given Function into the cache.
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void scan(Function *Fn);
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void evict(Function *Fn);
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/// Ensures that the given function is available in the cache.
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/// Returns the appropriate entry from the cache.
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const Optional<FunctionInfo> &ensureCached(Function *Fn);
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/// Get the alias summary for the given function
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/// Return nullptr if the summary is not found or not available
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const cflaa::AliasSummary *getAliasSummary(Function &Fn);
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AliasResult query(const MemoryLocation &LocA, const MemoryLocation &LocB);
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AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
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AAQueryInfo &AAQI) {
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if (LocA.Ptr == LocB.Ptr)
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return MustAlias;
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// Comparisons between global variables and other constants should be
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// handled by BasicAA.
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// CFLSteensAA may report NoAlias when comparing a GlobalValue and
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// ConstantExpr, but every query needs to have at least one Value tied to a
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// Function, and neither GlobalValues nor ConstantExprs are.
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if (isa<Constant>(LocA.Ptr) && isa<Constant>(LocB.Ptr))
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return AAResultBase::alias(LocA, LocB, AAQI);
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AliasResult QueryResult = query(LocA, LocB);
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if (QueryResult == MayAlias)
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return AAResultBase::alias(LocA, LocB, AAQI);
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return QueryResult;
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}
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private:
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std::function<const TargetLibraryInfo &(Function &)> GetTLI;
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/// Cached mapping of Functions to their StratifiedSets.
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/// If a function's sets are currently being built, it is marked
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/// in the cache as an Optional without a value. This way, if we
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/// have any kind of recursion, it is discernable from a function
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/// that simply has empty sets.
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DenseMap<Function *, Optional<FunctionInfo>> Cache;
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std::forward_list<cflaa::FunctionHandle<CFLSteensAAResult>> Handles;
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FunctionInfo buildSetsFrom(Function *F);
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};
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/// Analysis pass providing a never-invalidated alias analysis result.
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///
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/// FIXME: We really should refactor CFL to use the analysis more heavily, and
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/// in particular to leverage invalidation to trigger re-computation of sets.
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class CFLSteensAA : public AnalysisInfoMixin<CFLSteensAA> {
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friend AnalysisInfoMixin<CFLSteensAA>;
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static AnalysisKey Key;
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public:
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using Result = CFLSteensAAResult;
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CFLSteensAAResult run(Function &F, FunctionAnalysisManager &AM);
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};
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/// Legacy wrapper pass to provide the CFLSteensAAResult object.
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class CFLSteensAAWrapperPass : public ImmutablePass {
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std::unique_ptr<CFLSteensAAResult> Result;
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public:
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static char ID;
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CFLSteensAAWrapperPass();
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CFLSteensAAResult &getResult() { return *Result; }
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const CFLSteensAAResult &getResult() const { return *Result; }
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void initializePass() override;
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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};
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// createCFLSteensAAWrapperPass - This pass implements a set-based approach to
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// alias analysis.
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ImmutablePass *createCFLSteensAAWrapperPass();
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} // end namespace llvm
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#endif // LLVM_ANALYSIS_CFLSTEENSALIASANALYSIS_H
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