class BasicAAResult

Declaration

class BasicAAResult : public AAResultBase { /* full declaration omitted */ };

Description

This is the AA result object for the basic, local, and stateless alias analysis. It implements the AA query interface in an entirely stateless manner. As one consequence, it is never invalidated due to IR changes. While it does retain some storage, that is used as an optimization and not to preserve information from query to query. However it does retain handles to various other analyses and must be recomputed when those analyses are.

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:44

Inherits from: AAResultBase

Member Variables

private const llvm::DataLayout& DL

private const llvm::Function& F

private const llvm::TargetLibraryInfo& TLI

private llvm::AssumptionCache& AC

private llvm::DominatorTree* DT

private llvm::PhiValues* PV

private SmallPtrSet<const llvm::BasicBlock*, 8> VisitedPhiBBs

The following example shows the problem: %p = phi(%alloca1, %addr2) %l = load %ptr %addr1 = gep, %alloca2, 0, %l %addr2 = gep %alloca2, 0, (%l + 1) alias(%p, %addr1) -> MayAlias ! store %l, ...

private SmallPtrSet<const llvm::Value*, 16> Visited

Tracks instructions visited by pointsToConstantMemory.

Method Overview

• public BasicAAResult(const llvm::BasicAAResult & Arg)
• public BasicAAResult(llvm::BasicAAResult && Arg)
• public BasicAAResult(const llvm::DataLayout & DL, const llvm::Function & F, const llvm::TargetLibraryInfo & TLI, llvm::AssumptionCache & AC, llvm::DominatorTree * DT = nullptr, llvm::PhiValues * PV = nullptr)
• private static llvm::BasicAAResult::DecomposedGEP DecomposeGEPExpression(const llvm::Value * V, const llvm::DataLayout & DL, llvm::AssumptionCache * AC, llvm::DominatorTree * DT)
• public llvm::AliasResult alias(const llvm::MemoryLocation & LocA, const llvm::MemoryLocation & LocB, llvm::AAQueryInfo & AAQI)
• private llvm::AliasResult aliasCheck(const llvm::Value * V1, llvm::LocationSize V1Size, const llvm::Value * V2, llvm::LocationSize V2Size, llvm::AAQueryInfo & AAQI)
• private llvm::AliasResult aliasCheckRecursive(const llvm::Value * V1, llvm::LocationSize V1Size, const llvm::Value * V2, llvm::LocationSize V2Size, llvm::AAQueryInfo & AAQI, const llvm::Value * O1, const llvm::Value * O2)
• private llvm::AliasResult aliasGEP(const llvm::GEPOperator * V1, llvm::LocationSize V1Size, const llvm::Value * V2, llvm::LocationSize V2Size, const llvm::Value * UnderlyingV1, const llvm::Value * UnderlyingV2, llvm::AAQueryInfo & AAQI)
• private llvm::AliasResult aliasPHI(const llvm::PHINode * PN, llvm::LocationSize PNSize, const llvm::Value * V2, llvm::LocationSize V2Size, llvm::AAQueryInfo & AAQI)
• private llvm::AliasResult aliasSelect(const llvm::SelectInst * SI, llvm::LocationSize SISize, const llvm::Value * V2, llvm::LocationSize V2Size, llvm::AAQueryInfo & AAQI)
• private bool constantOffsetHeuristic(const llvm::BasicAAResult::DecomposedGEP & GEP, llvm::LocationSize V1Size, llvm::LocationSize V2Size, llvm::AssumptionCache * AC, llvm::DominatorTree * DT)
• public llvm::ModRefInfo getArgModRefInfo(const llvm::CallBase * Call, unsigned int ArgIdx)
• public llvm::FunctionModRefBehavior getModRefBehavior(const llvm::CallBase * Call)
• public llvm::FunctionModRefBehavior getModRefBehavior(const llvm::Function * Fn)
• public llvm::ModRefInfo getModRefInfo(const llvm::CallBase * Call1, const llvm::CallBase * Call2, llvm::AAQueryInfo & AAQI)
• public llvm::ModRefInfo getModRefInfo(const llvm::CallBase * Call, const llvm::MemoryLocation & Loc, llvm::AAQueryInfo & AAQI)
• public bool invalidate(llvm::Function & Fn, const llvm::PreservedAnalyses & PA, FunctionAnalysisManager::Invalidator & Inv)
• private bool isValueEqualInPotentialCycles(const llvm::Value * V1, const llvm::Value * V2)
• public bool pointsToConstantMemory(const llvm::MemoryLocation & Loc, llvm::AAQueryInfo & AAQI, bool OrLocal)
• private void subtractDecomposedGEPs(llvm::BasicAAResult::DecomposedGEP & DestGEP, const llvm::BasicAAResult::DecomposedGEP & SrcGEP)

Methods

¶BasicAAResult(const llvm::BasicAAResult& Arg)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:60

Parameters

const llvm::BasicAAResult& Arg

¶BasicAAResult(llvm::BasicAAResult&& Arg)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:63

Parameters

llvm::BasicAAResult&& Arg

¶BasicAAResult(const llvm::DataLayout& DL,
              const llvm::Function& F,
              const llvm::TargetLibraryInfo& TLI,
              llvm::AssumptionCache& AC,
              llvm::DominatorTree* DT = nullptr,
              llvm::PhiValues* PV = nullptr)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:55

Parameters

const llvm::DataLayout& DL

const llvm::Function& F

const llvm::TargetLibraryInfo& TLI

llvm::AssumptionCache& AC

llvm::DominatorTree* DT = nullptr

llvm::PhiValues* PV = nullptr

¶static llvm::BasicAAResult::DecomposedGEP
DecomposeGEPExpression(const llvm::Value* V,
                       const llvm::DataLayout& DL,
                       llvm::AssumptionCache* AC,
                       llvm::DominatorTree* DT)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:117

Parameters

const llvm::Value* V

const llvm::DataLayout& DL

llvm::AssumptionCache* AC

llvm::DominatorTree* DT

¶llvm::AliasResult alias(
    const llvm::MemoryLocation& LocA,
    const llvm::MemoryLocation& LocB,
    llvm::AAQueryInfo& AAQI)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:71

Parameters

const llvm::MemoryLocation& LocA

const llvm::MemoryLocation& LocB

llvm::AAQueryInfo& AAQI

¶llvm::AliasResult aliasCheck(
    const llvm::Value* V1,
    llvm::LocationSize V1Size,
    const llvm::Value* V2,
    llvm::LocationSize V2Size,
    llvm::AAQueryInfo& AAQI)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:150

Parameters

const llvm::Value* V1

llvm::LocationSize V1Size

const llvm::Value* V2

llvm::LocationSize V2Size

llvm::AAQueryInfo& AAQI

¶llvm::AliasResult aliasCheckRecursive(
    const llvm::Value* V1,
    llvm::LocationSize V1Size,
    const llvm::Value* V2,
    llvm::LocationSize V2Size,
    llvm::AAQueryInfo& AAQI,
    const llvm::Value* O1,
    const llvm::Value* O2)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:154

Parameters

const llvm::Value* V1

llvm::LocationSize V1Size

const llvm::Value* V2

llvm::LocationSize V2Size

llvm::AAQueryInfo& AAQI

const llvm::Value* O1

const llvm::Value* O2

¶llvm::AliasResult aliasGEP(
    const llvm::GEPOperator* V1,
    llvm::LocationSize V1Size,
    const llvm::Value* V2,
    llvm::LocationSize V2Size,
    const llvm::Value* UnderlyingV1,
    const llvm::Value* UnderlyingV2,
    llvm::AAQueryInfo& AAQI)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:138

Parameters

const llvm::GEPOperator* V1

llvm::LocationSize V1Size

const llvm::Value* V2

llvm::LocationSize V2Size

const llvm::Value* UnderlyingV1

const llvm::Value* UnderlyingV2

llvm::AAQueryInfo& AAQI

¶llvm::AliasResult aliasPHI(
    const llvm::PHINode* PN,
    llvm::LocationSize PNSize,
    const llvm::Value* V2,
    llvm::LocationSize V2Size,
    llvm::AAQueryInfo& AAQI)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:143

Parameters

const llvm::PHINode* PN

llvm::LocationSize PNSize

const llvm::Value* V2

llvm::LocationSize V2Size

llvm::AAQueryInfo& AAQI

¶llvm::AliasResult aliasSelect(
    const llvm::SelectInst* SI,
    llvm::LocationSize SISize,
    const llvm::Value* V2,
    llvm::LocationSize V2Size,
    llvm::AAQueryInfo& AAQI)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:146

Parameters

const llvm::SelectInst* SI

llvm::LocationSize SISize

const llvm::Value* V2

llvm::LocationSize V2Size

llvm::AAQueryInfo& AAQI

¶bool constantOffsetHeuristic(
    const llvm::BasicAAResult::DecomposedGEP& GEP,
    llvm::LocationSize V1Size,
    llvm::LocationSize V2Size,
    llvm::AssumptionCache* AC,
    llvm::DominatorTree* DT)

Description

A Heuristic for aliasGEP that searches for a constant offset between the variables. GetLinearExpression has some limitations, as generally zext(%x + 1) != zext(%x) + zext(1) if the arithmetic overflows. GetLinearExpression will therefore conservatively refuse to decompose these expressions. However, we know that, for all %x, zext(%x) != zext(%x + 1), even if the addition overflows.

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:129

Parameters

const llvm::BasicAAResult::DecomposedGEP& GEP

llvm::LocationSize V1Size

llvm::LocationSize V2Size

llvm::AssumptionCache* AC

llvm::DominatorTree* DT

¶llvm::ModRefInfo getArgModRefInfo(
    const llvm::CallBase* Call,
    unsigned int ArgIdx)

Description

Get the location associated with a pointer argument of a callsite.

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:85

Parameters

const llvm::CallBase* Call

unsigned int ArgIdx

¶llvm::FunctionModRefBehavior getModRefBehavior(
    const llvm::CallBase* Call)

Description

Returns the behavior when calling the given call site.

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:88

Parameters

const llvm::CallBase* Call

¶llvm::FunctionModRefBehavior getModRefBehavior(
    const llvm::Function* Fn)

Description

Returns the behavior when calling the given function. For use when the call site is not known.

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:92

Parameters

const llvm::Function* Fn

¶llvm::ModRefInfo getModRefInfo(
    const llvm::CallBase* Call1,
    const llvm::CallBase* Call2,
    llvm::AAQueryInfo& AAQI)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:77

Parameters

const llvm::CallBase* Call1

const llvm::CallBase* Call2

llvm::AAQueryInfo& AAQI

¶llvm::ModRefInfo getModRefInfo(
    const llvm::CallBase* Call,
    const llvm::MemoryLocation& Loc,
    llvm::AAQueryInfo& AAQI)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:74

Parameters

const llvm::CallBase* Call

const llvm::MemoryLocation& Loc

llvm::AAQueryInfo& AAQI

¶bool invalidate(
    llvm::Function& Fn,
    const llvm::PreservedAnalyses& PA,
    FunctionAnalysisManager::Invalidator& Inv)

Description

Handle invalidation events in the new pass manager.

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:68

Parameters

llvm::Function& Fn

const llvm::PreservedAnalyses& PA

FunctionAnalysisManager::Invalidator& Inv

¶bool isValueEqualInPotentialCycles(
    const llvm::Value* V1,
    const llvm::Value* V2)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:133

Parameters

const llvm::Value* V1

const llvm::Value* V2

¶bool pointsToConstantMemory(
    const llvm::MemoryLocation& Loc,
    llvm::AAQueryInfo& AAQI,
    bool OrLocal)

Description

Chases pointers until we find a (constant global) or not.

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:81

Parameters

const llvm::MemoryLocation& Loc

llvm::AAQueryInfo& AAQI

bool OrLocal

¶void subtractDecomposedGEPs(
    llvm::BasicAAResult::DecomposedGEP& DestGEP,
    const llvm::BasicAAResult::DecomposedGEP&
        SrcGEP)

Declared at: llvm/include/llvm/Analysis/BasicAliasAnalysis.h:135

Parameters

llvm::BasicAAResult::DecomposedGEP& DestGEP

const llvm::BasicAAResult::DecomposedGEP& SrcGEP