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llvm-mirror/include/llvm/Analysis/ObjCARCAliasAnalysis.h
Alina Sbirlea 3fc1696aca [AliasAnalysis] Second prototype to cache BasicAA / anyAA state.
Summary:
Adding contained caching to AliasAnalysis. BasicAA is currently the only one using it.

AA changes:
- This patch is pulling the caches from BasicAAResults to AAResults, meaning the getModRefInfo call benefits from the IsCapturedCache as well when in "batch mode".
- All AAResultBase implementations add the QueryInfo member to all APIs. AAResults APIs maintain wrapper APIs such that all alias()/getModRefInfo call sites are unchanged.
- AA now provides a BatchAAResults type as a wrapper to AAResults. It keeps the AAResults instance and a QueryInfo instantiated to batch mode. It delegates all work to the AAResults instance with the batched QueryInfo. More API wrappers may be needed in BatchAAResults; only the minimum needed is currently added.

MemorySSA changes:
- All walkers are now templated on the AA used (AliasAnalysis=AAResults or BatchAAResults).
- At build time, we optimize uses; now we create a local walker (lives only as long as OptimizeUses does) using BatchAAResults.
- All Walkers have an internal AA and only use that now, never the AA in MemorySSA. The Walkers receive the AA they will use when built.

- The walker we use for queries after the build is instantiated on AliasAnalysis and is built after building MemorySSA and setting AA.
- All static methods doing walking are now templated on AliasAnalysisType if they are used both during build and after. If used only during build, the method now only takes a BatchAAResults. If used only after build, the method now takes an AliasAnalysis.

Subscribers: sanjoy, arsenm, jvesely, nhaehnle, jlebar, george.burgess.iv, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59315

llvm-svn: 356783
2019-03-22 17:22:19 +00:00

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3.4 KiB
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//===- ObjCARCAliasAnalysis.h - ObjC ARC Alias Analysis ---------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
/// \file
/// This file declares a simple ARC-aware AliasAnalysis using special knowledge
/// of Objective C to enhance other optimization passes which rely on the Alias
/// Analysis infrastructure.
///
/// WARNING: This file knows about certain library functions. It recognizes them
/// by name, and hardwires knowledge of their semantics.
///
/// WARNING: This file knows about how certain Objective-C library functions are
/// used. Naive LLVM IR transformations which would otherwise be
/// behavior-preserving may break these assumptions.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
#define LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Pass.h"
namespace llvm {
namespace objcarc {
/// This is a simple alias analysis implementation that uses knowledge
/// of ARC constructs to answer queries.
///
/// TODO: This class could be generalized to know about other ObjC-specific
/// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing
/// even though their offsets are dynamic.
class ObjCARCAAResult : public AAResultBase<ObjCARCAAResult> {
friend AAResultBase<ObjCARCAAResult>;
const DataLayout &DL;
public:
explicit ObjCARCAAResult(const DataLayout &DL) : AAResultBase(), DL(DL) {}
ObjCARCAAResult(ObjCARCAAResult &&Arg)
: AAResultBase(std::move(Arg)), DL(Arg.DL) {}
/// Handle invalidation events from the new pass manager.
///
/// By definition, this result is stateless and so remains valid.
bool invalidate(Function &, const PreservedAnalyses &,
FunctionAnalysisManager::Invalidator &) {
return false;
}
AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB,
AAQueryInfo &AAQI);
bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
bool OrLocal);
using AAResultBase::getModRefBehavior;
FunctionModRefBehavior getModRefBehavior(const Function *F);
using AAResultBase::getModRefInfo;
ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
AAQueryInfo &AAQI);
};
/// Analysis pass providing a never-invalidated alias analysis result.
class ObjCARCAA : public AnalysisInfoMixin<ObjCARCAA> {
friend AnalysisInfoMixin<ObjCARCAA>;
static AnalysisKey Key;
public:
typedef ObjCARCAAResult Result;
ObjCARCAAResult run(Function &F, FunctionAnalysisManager &AM);
};
/// Legacy wrapper pass to provide the ObjCARCAAResult object.
class ObjCARCAAWrapperPass : public ImmutablePass {
std::unique_ptr<ObjCARCAAResult> Result;
public:
static char ID;
ObjCARCAAWrapperPass();
ObjCARCAAResult &getResult() { return *Result; }
const ObjCARCAAResult &getResult() const { return *Result; }
bool doInitialization(Module &M) override;
bool doFinalization(Module &M) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
};
} // namespace objcarc
} // namespace llvm
#endif