BasicAliasAnalysis.cpp File Reference

#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/KnownBits.h"
#include "llvm/Support/SaveAndRestore.h"
#include <cassert>
#include <cstdint>
#include <cstdlib>
#include <optional>
#include <utility>

Go to the source code of this file.

Classes
struct	llvm::BasicAAResult::DecomposedGEP

Macros
#define	DEBUG_TYPE   "basicaa"

Functions
	STATISTIC (SearchLimitReached, "Number of times the limit to " "decompose GEPs is reached")
	SearchLimitReached / SearchTimes shows how often the limit of to decompose GEPs is reached.
	STATISTIC (SearchTimes, "Number of times a GEP is decomposed")
static std::optional< TypeSize >	getObjectSize (const Value *V, const DataLayout &DL, const TargetLibraryInfo &TLI, bool NullIsValidLoc, bool RoundToAlign=false)
	Returns the size of the object specified by V or UnknownSize if unknown.
static bool	isObjectSmallerThan (const Value *V, TypeSize Size, const DataLayout &DL, const TargetLibraryInfo &TLI, bool NullIsValidLoc)
	Returns true if we can prove that the object specified by V is smaller than Size.
static TypeSize	getMinimalExtentFrom (const Value &V, const LocationSize &LocSize, const DataLayout &DL, bool NullIsValidLoc)
	Return the minimal extent from V to the end of the underlying object, assuming the result is used in an aliasing query.
static bool	isObjectSize (const Value *V, TypeSize Size, const DataLayout &DL, const TargetLibraryInfo &TLI, bool NullIsValidLoc)
	Returns true if we can prove that the object specified by V has size Size.
static bool	areBothVScale (const Value *V1, const Value *V2)
	Return true if both V1 and V2 are VScale.
static bool	isNotInCycle (const Instruction *I, const DominatorTree *DT, const LoopInfo *LI)
static LinearExpression	GetLinearExpression (const CastedValue &Val, const DataLayout &DL, unsigned Depth, AssumptionCache *AC, DominatorTree *DT)
	Analyzes the specified value as a linear expression: "A*V + B", where A and B are constant integers.
static void	adjustToIndexSize (APInt &Offset, unsigned IndexSize)
	To ensure a pointer offset fits in an integer of size IndexSize (in bits) when that size is smaller than the maximum index size.
static bool	isIntrinsicCall (const CallBase *Call, Intrinsic::ID IID)
static const Function *	getParent (const Value *V)
static bool	notDifferentParent (const Value *O1, const Value *O2)
static bool	isBaseOfObject (const Value *V)
	Return true if we know V to the base address of the corresponding memory object.
static AliasResult	MergeAliasResults (AliasResult A, AliasResult B)
	INITIALIZE_PASS_BEGIN (BasicAAWrapperPass, "basic-aa", "Basic Alias Analysis (stateless AA impl)", true, true) INITIALIZE_PASS_END(BasicAAWrapperPass
basic Basic Alias	Analysis (stateless AA impl)"

Variables
static cl::opt< bool >	EnableRecPhiAnalysis ("basic-aa-recphi", cl::Hidden, cl::init(true))
	Enable analysis of recursive PHI nodes.
static cl::opt< bool >	EnableSeparateStorageAnalysis ("basic-aa-separate-storage", cl::Hidden, cl::init(true))
static const unsigned	MaxLookupSearchDepth = 6
basic	aa
basic Basic Alias	true

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "basicaa"

Definition at line 64 of file BasicAliasAnalysis.cpp.

Function Documentation

adjustToIndexSize()

static void adjustToIndexSize ( APInt &  Offset, unsigned  IndexSize  )

static

To ensure a pointer offset fits in an integer of size IndexSize (in bits) when that size is smaller than the maximum index size.

This is an issue, for example, in particular for 32b pointers with negative indices that rely on two's complement wrap-arounds for precise alias information where the maximum index size is 64b.

Definition at line 500 of file BasicAliasAnalysis.cpp.

References assert(), and llvm::Offset.

Analysis()

basic Basic Alias Analysis

(

stateless AA

impl

)

areBothVScale()

static bool areBothVScale ( const Value *  V1, const Value *  V2  )

static

Return true if both V1 and V2 are VScale.

Definition at line 193 of file BasicAliasAnalysis.cpp.

References llvm::PatternMatch::m_VScale(), and llvm::PatternMatch::match().

GetLinearExpression()

static LinearExpression GetLinearExpression ( const CastedValue &  Val, const DataLayout &  DL, unsigned  Depth, AssumptionCache *  AC, DominatorTree *  DT  )

static

Analyzes the specified value as a linear expression: "A*V + B", where A and B are constant integers.

Definition at line 402 of file BasicAliasAnalysis.cpp.

References llvm::Depth, DL, GetLinearExpression(), and RHS.

Referenced by GetLinearExpression().

getMinimalExtentFrom()

static TypeSize getMinimalExtentFrom ( const Value &  V, const LocationSize &  LocSize, const DataLayout &  DL, bool  NullIsValidLoc  )

static

Return the minimal extent from V to the end of the underlying object, assuming the result is used in an aliasing query.

E.g., we do use the query location size and the fact that null pointers cannot alias here.

Definition at line 165 of file BasicAliasAnalysis.cpp.

References DL, llvm::TypeSize::getFixed(), llvm::details::FixedOrScalableQuantity< LeafTy, ValueTy >::getKnownMinValue(), llvm::LocationSize::getValue(), and llvm::LocationSize::isPrecise().

getObjectSize()

static std::optional< TypeSize > getObjectSize ( const Value *  V, const DataLayout &  DL, const TargetLibraryInfo &  TLI, bool  NullIsValidLoc, bool  RoundToAlign = false  )

static

Returns the size of the object specified by V or UnknownSize if unknown.

Definition at line 105 of file BasicAliasAnalysis.cpp.

References DL, llvm::TypeSize::getFixed(), llvm::getObjectSize(), llvm::ObjectSizeOpts::NullIsUnknownSize, llvm::ObjectSizeOpts::RoundToAlign, and Size.

getParent()

static const Function * getParent ( const Value *  V )

static

Definition at line 878 of file BasicAliasAnalysis.cpp.

References llvm::GlobalValue::getParent().

Referenced by llvm::CanonicalLoopInfo::assertOK(), llvm::slpvectorizer::BoUpSLP::canVectorizeLoads(), llvm::CloneAndPruneIntoFromInst(), llvm::JumpThreadingPass::computeValueKnownInPredecessorsImpl(), detectPopcountIdiom(), ensureValueAvailableInSuccessor(), llvm::CodeExtractor::findAllocas(), llvm::InstCombinerImpl::foldOpIntoPhi(), llvm::RegionBase< Tr >::getDepth(), llvm::VPBasicBlock::getEnclosingLoopRegion(), llvm::getLiveRegMap(), getLocalFunctionMetadata(), llvm::CoroIdAsyncInst::getStorage(), isBlockValidForExtraction(), llvm::PHINode::isComplete(), llvm::VPBasicBlock::isExiting(), llvm::CodeExtractor::isLegalToShrinkwrapLifetimeMarkers(), isOnlyUsedInEntryBlock(), isUsedOutsideOfDefiningBlock(), LLVMGetBasicBlockParent(), LLVMGetGlobalParent(), LLVMGetInstructionParent(), LLVMGetParamParent(), notDifferentParent(), llvm::MachineFunction::print(), llvm::LoopVectorizePass::processLoop(), redirectValuesFromPredecessorsToPhi(), llvm::AssumptionCache::registerAssumption(), llvm::ScheduleDAGMI::schedule(), llvm::ScheduleDAGMILive::schedule(), llvm::VLIWMachineScheduler::schedule(), llvm::SIScheduleDAGMI::schedule(), splitCallSite(), and llvm::GenericCycle< ContextT >::verifyCycle().

INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	BasicAAWrapperPass	,
		"basic-aa"	,
		"Basic Alias Analysis (stateless AA impl)"	,
		true	,
		true
	)

isBaseOfObject()

static bool isBaseOfObject ( const Value *  V )

static

Return true if we know V to the base address of the corresponding memory object.

This implies that any address less than V must be out of bounds for the underlying object. Note that just being isIdentifiedObject() is not enough - For example, a negative offset from a noalias argument or call can be inbounds w.r.t the actual underlying object.

Definition at line 1070 of file BasicAliasAnalysis.cpp.

isIntrinsicCall()

static bool isIntrinsicCall ( const CallBase *  Call, Intrinsic::ID  IID  )

static

Definition at line 824 of file BasicAliasAnalysis.cpp.

References II.

Referenced by llvm::BasicAAResult::getModRefInfo(), isPreserveArrayIndex(), isPreserveStructIndex(), and isPreserveUnionIndex().

isNotInCycle()

static bool isNotInCycle ( const Instruction *  I, const DominatorTree *  DT, const LoopInfo *  LI  )

static

Definition at line 209 of file BasicAliasAnalysis.cpp.

References llvm::SmallVectorBase< Size_T >::empty(), I, llvm::isPotentiallyReachableFromMany(), and llvm::successors().

Referenced by llvm::EarliestEscapeInfo::isNotCapturedBefore().

isObjectSize()

static bool isObjectSize ( const Value *  V, TypeSize  Size, const DataLayout &  DL, const TargetLibraryInfo &  TLI, bool  NullIsValidLoc  )

static

Returns true if we can prove that the object specified by V has size Size.

Definition at line 185 of file BasicAliasAnalysis.cpp.

References DL, llvm::getObjectSize(), and Size.

isObjectSmallerThan()

static bool isObjectSmallerThan ( const Value *  V, TypeSize  Size, const DataLayout &  DL, const TargetLibraryInfo &  TLI, bool  NullIsValidLoc  )

static

Returns true if we can prove that the object specified by V is smaller than Size.

Definition at line 121 of file BasicAliasAnalysis.cpp.

References DL, llvm::getObjectSize(), llvm::isIdentifiedObject(), llvm::details::FixedOrScalableQuantity< TypeSize, uint64_t >::isKnownLT(), and Size.

MergeAliasResults()

static AliasResult MergeAliasResults ( AliasResult  A, AliasResult  B  )

static

Definition at line 1390 of file BasicAliasAnalysis.cpp.

References A, B, llvm::AliasResult::MayAlias, llvm::AliasResult::MustAlias, and llvm::AliasResult::PartialAlias.

notDifferentParent()

static bool notDifferentParent ( const Value *  O1, const Value *  O2  )

static

Definition at line 891 of file BasicAliasAnalysis.cpp.

References getParent().

Referenced by llvm::BasicAAResult::alias(), and llvm::BasicAAResult::getModRefInfo().

STATISTIC() [1/2]

STATISTIC	(	SearchLimitReached	,
		"Number of times the limit to " "decompose GEPs is reached"
	)

SearchLimitReached / SearchTimes shows how often the limit of to decompose GEPs is reached.

It will affect the precision of basic alias analysis.

STATISTIC() [2/2]

STATISTIC	(	SearchTimes	,
		"Number of times a GEP is decomposed"
	)

Variable Documentation

aa

basic aa

Definition at line 1993 of file BasicAliasAnalysis.cpp.

EnableRecPhiAnalysis

cl::opt< bool > EnableRecPhiAnalysis("basic-aa-recphi", cl::Hidden, cl::init(true)) ( "basic-aa-recphi"  , cl::Hidden  , cl::init(true)    )

static

Enable analysis of recursive PHI nodes.

EnableSeparateStorageAnalysis

cl::opt< bool > EnableSeparateStorageAnalysis("basic-aa-separate-storage", cl::Hidden, cl::init(true)) ( "basic-aa-separate-storage"  , cl::Hidden  , cl::init(true)    )

static

MaxLookupSearchDepth

const unsigned MaxLookupSearchDepth = 6

static

Definition at line 84 of file BasicAliasAnalysis.cpp.

true

print machine Print Machine Uniformity Info true

Examples

/home/buildbot/as-worker-4/publish-doxygen-docs/llvm-project/llvm/include/llvm/ADT/ilist_node.h.

Definition at line 1994 of file BasicAliasAnalysis.cpp.

Referenced by llvm::PotentialValuesState< MemberTy >::contains(), llvm::PPCInstrInfo::getFMAPatterns(), getIsFloat(), llvm::X86CallLowering::lowerCall(), llvm::MIPatternMatch::GCstAndRegMatch::match(), llvm::MIPatternMatch::GFCstAndRegMatch::match(), matchIntrinsicType(), llvm::ScopedHandle< HandleTraits >::operator bool(), llvm::orc::BlockFreqQuery::operator()(), and llvm::TargetLowering::SimplifyDemandedVectorElts().