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6150530377
This was originally a pointer to support pass managers which didn't use AnalysisManagers. However, that doesn't realistically come up much and the complexity of supporting it doesn't really make sense. In fact, *many* parts of the pass manager were just assuming the pointer was never null already. This at least makes it much more explicit and clear. llvm-svn: 263219
148 lines
4.5 KiB
C++
148 lines
4.5 KiB
C++
//===- CFLAliasAnalysis.h - CFL-Based Alias Analysis Interface ---*- 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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/// \file
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/// This is the interface for LLVM's primary stateless and local alias analysis.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_CFLALIASANALYSIS_H
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#define LLVM_ANALYSIS_CFLALIASANALYSIS_H
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#include "llvm/Analysis/AliasAnalysis.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/None.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/ValueHandle.h"
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#include "llvm/Pass.h"
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#include <forward_list>
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namespace llvm {
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class CFLAAResult : public AAResultBase<CFLAAResult> {
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friend AAResultBase<CFLAAResult>;
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struct FunctionInfo;
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public:
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explicit CFLAAResult();
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CFLAAResult(CFLAAResult &&Arg);
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~CFLAAResult();
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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 &) { return false; }
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/// \brief 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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/// \brief 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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AliasResult query(const MemoryLocation &LocA, const MemoryLocation &LocB);
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AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
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if (LocA.Ptr == LocB.Ptr)
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return LocA.Size == LocB.Size ? MustAlias : PartialAlias;
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// Comparisons between global variables and other constants should be
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// handled by BasicAA.
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// TODO: ConstantExpr handling -- CFLAA may report NoAlias when comparing
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// a GlobalValue and ConstantExpr, but every query needs to have at least
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// one Value tied to a Function, and neither GlobalValues nor ConstantExprs
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// are.
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if (isa<Constant>(LocA.Ptr) && isa<Constant>(LocB.Ptr))
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return AAResultBase::alias(LocA, LocB);
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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);
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return QueryResult;
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}
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private:
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struct FunctionHandle final : public CallbackVH {
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FunctionHandle(Function *Fn, CFLAAResult *Result)
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: CallbackVH(Fn), Result(Result) {
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assert(Fn != nullptr);
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assert(Result != nullptr);
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}
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void deleted() override { removeSelfFromCache(); }
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void allUsesReplacedWith(Value *) override { removeSelfFromCache(); }
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private:
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CFLAAResult *Result;
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void removeSelfFromCache() {
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assert(Result != nullptr);
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auto *Val = getValPtr();
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Result->evict(cast<Function>(Val));
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setValPtr(nullptr);
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}
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};
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/// \brief 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<FunctionHandle> 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 CFLAA : public AnalysisInfoMixin<CFLAA> {
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friend AnalysisInfoMixin<CFLAA>;
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static char PassID;
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public:
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typedef CFLAAResult Result;
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CFLAAResult run(Function &F, AnalysisManager<Function> &AM);
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};
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/// Legacy wrapper pass to provide the CFLAAResult object.
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class CFLAAWrapperPass : public ImmutablePass {
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std::unique_ptr<CFLAAResult> Result;
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public:
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static char ID;
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CFLAAWrapperPass();
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CFLAAResult &getResult() { return *Result; }
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const CFLAAResult &getResult() const { return *Result; }
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bool doInitialization(Module &M) override;
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bool doFinalization(Module &M) override;
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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};
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//===--------------------------------------------------------------------===//
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//
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// createCFLAAWrapperPass - This pass implements a set-based approach to
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// alias analysis.
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//
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ImmutablePass *createCFLAAWrapperPass();
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}
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#endif
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