LLVM 20.0.0git
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llvm::MemorySSA Class Reference

Encapsulates MemorySSA, including all data associated with memory accesses. More...

#include "llvm/Analysis/MemorySSA.h"

Classes

class  CachingWalker
 A MemorySSAWalker that does AA walks to disambiguate accesses. More...
 
class  ClobberWalkerBase
 
class  OptimizeUses
 This class is a batch walker of all MemoryUse's in the program, and points their defining access at the thing that actually clobbers them. More...
 
class  SkipSelfWalker
 

Public Types

enum class  VerificationLevel { Fast , Full }
 
enum  InsertionPlace { Beginning , End , BeforeTerminator }
 Used in various insertion functions to specify whether we are talking about the beginning or end of a block. More...
 
using AccessList = iplist< MemoryAccess, ilist_tag< MSSAHelpers::AllAccessTag > >
 
using DefsList = simple_ilist< MemoryAccess, ilist_tag< MSSAHelpers::DefsOnlyTag > >
 

Public Member Functions

 MemorySSA (Function &, AliasAnalysis *, DominatorTree *)
 
 MemorySSA (Loop &, AliasAnalysis *, DominatorTree *)
 
 MemorySSA (MemorySSA &&)=delete
 
 ~MemorySSA ()
 
MemorySSAWalkergetWalker ()
 
MemorySSAWalkergetSkipSelfWalker ()
 
MemoryUseOrDefgetMemoryAccess (const Instruction *I) const
 Given a memory Mod/Ref'ing instruction, get the MemorySSA access associated with it.
 
MemoryPhigetMemoryAccess (const BasicBlock *BB) const
 
DominatorTreegetDomTree () const
 
void dump () const
 
void print (raw_ostream &) const
 
bool isLiveOnEntryDef (const MemoryAccess *MA) const
 Return true if MA represents the live on entry value.
 
MemoryAccessgetLiveOnEntryDef () const
 
const AccessListgetBlockAccesses (const BasicBlock *BB) const
 Return the list of MemoryAccess's for a given basic block.
 
const DefsListgetBlockDefs (const BasicBlock *BB) const
 Return the list of MemoryDef's and MemoryPhi's for a given basic block.
 
bool locallyDominates (const MemoryAccess *A, const MemoryAccess *B) const
 Given two memory accesses in the same basic block, determine whether MemoryAccess A dominates MemoryAccess B.
 
bool dominates (const MemoryAccess *A, const MemoryAccess *B) const
 Given two memory accesses in potentially different blocks, determine whether MemoryAccess A dominates MemoryAccess B.
 
bool dominates (const MemoryAccess *A, const Use &B) const
 Given a MemoryAccess and a Use, determine whether MemoryAccess A dominates Use B.
 
void verifyMemorySSA (VerificationLevel=VerificationLevel::Fast) const
 Verify that MemorySSA is self consistent (IE definitions dominate all uses, uses appear in the right places).
 
void ensureOptimizedUses ()
 By default, uses are not optimized during MemorySSA construction.
 
AliasAnalysisgetAA ()
 

Protected Member Functions

template<typename IterT >
void verifyOrderingDominationAndDefUses (IterT Blocks, VerificationLevel=VerificationLevel::Fast) const
 Verify ordering: the order and existence of MemoryAccesses matches the order and existence of memory affecting instructions.
 
template<typename IterT >
void verifyDominationNumbers (IterT Blocks) const
 Verify that all of the blocks we believe to have valid domination numbers actually have valid domination numbers.
 
template<typename IterT >
void verifyPrevDefInPhis (IterT Blocks) const
 
AccessListgetWritableBlockAccesses (const BasicBlock *BB) const
 
DefsListgetWritableBlockDefs (const BasicBlock *BB) const
 
void moveTo (MemoryUseOrDef *What, BasicBlock *BB, AccessList::iterator Where)
 
void moveTo (MemoryAccess *What, BasicBlock *BB, InsertionPlace Point)
 
void renamePass (BasicBlock *BB, MemoryAccess *IncomingVal, SmallPtrSetImpl< BasicBlock * > &Visited)
 
void removeFromLookups (MemoryAccess *)
 Properly remove MA from all of MemorySSA's lookup tables.
 
void removeFromLists (MemoryAccess *, bool ShouldDelete=true)
 Properly remove MA from all of MemorySSA's lists.
 
void insertIntoListsForBlock (MemoryAccess *, const BasicBlock *, InsertionPlace)
 
void insertIntoListsBefore (MemoryAccess *, const BasicBlock *, AccessList::iterator)
 
MemoryUseOrDefcreateDefinedAccess (Instruction *, MemoryAccess *, const MemoryUseOrDef *Template=nullptr, bool CreationMustSucceed=true)
 

Friends

class MemorySSAUpdater
 

Detailed Description

Encapsulates MemorySSA, including all data associated with memory accesses.

Definition at line 701 of file MemorySSA.h.

Member Typedef Documentation

◆ AccessList

Definition at line 752 of file MemorySSA.h.

◆ DefsList

Definition at line 753 of file MemorySSA.h.

Member Enumeration Documentation

◆ InsertionPlace

Used in various insertion functions to specify whether we are talking about the beginning or end of a block.

Enumerator
Beginning 
End 
BeforeTerminator 

Definition at line 790 of file MemorySSA.h.

◆ VerificationLevel

Enumerator
Fast 
Full 

Definition at line 783 of file MemorySSA.h.

Constructor & Destructor Documentation

◆ MemorySSA() [1/3]

MemorySSA::MemorySSA ( Function Func,
AliasAnalysis AA,
DominatorTree DT 
)

Definition at line 1233 of file MemorySSA.cpp.

References assert(), llvm::Function::begin(), llvm::Function::end(), and getWalker().

◆ MemorySSA() [2/3]

MemorySSA::MemorySSA ( Loop L,
AliasAnalysis AA,
DominatorTree DT 
)

Definition at line 1251 of file MemorySSA.cpp.

References assert(), getWalker(), and llvm::map_range().

◆ MemorySSA() [3/3]

llvm::MemorySSA::MemorySSA ( MemorySSA &&  )
delete

◆ ~MemorySSA()

MemorySSA::~MemorySSA ( )

Definition at line 1272 of file MemorySSA.cpp.

References llvm::User::dropAllReferences().

Member Function Documentation

◆ createDefinedAccess()

MemoryUseOrDef * MemorySSA::createDefinedAccess ( Instruction I,
MemoryAccess Definition,
const MemoryUseOrDef Template = nullptr,
bool  CreationMustSucceed = true 
)
protected

◆ dominates() [1/2]

bool MemorySSA::dominates ( const MemoryAccess A,
const MemoryAccess B 
) const

Given two memory accesses in potentially different blocks, determine whether MemoryAccess A dominates MemoryAccess B.

Definition at line 2173 of file MemorySSA.cpp.

References llvm::DominatorTree::dominates(), llvm::MemoryAccess::getBlock(), isLiveOnEntryDef(), and locallyDominates().

Referenced by llvm::canSinkOrHoistInst(), checkClobberSanity(), dominates(), getMatchingValue(), verifyOrderingDominationAndDefUses(), and writtenBetween().

◆ dominates() [2/2]

bool MemorySSA::dominates ( const MemoryAccess A,
const Use B 
) const

Given a MemoryAccess and a Use, determine whether MemoryAccess A dominates Use B.

Definition at line 2186 of file MemorySSA.cpp.

References llvm::DominatorTree::dominates(), dominates(), llvm::MemoryAccess::getBlock(), llvm::Use::getUser(), and locallyDominates().

◆ dump()

LLVM_DUMP_METHOD void MemorySSA::dump ( ) const

Definition at line 1902 of file MemorySSA.cpp.

References llvm::dbgs(), and print().

◆ ensureOptimizedUses()

void MemorySSA::ensureOptimizedUses ( )

By default, uses are not optimized during MemorySSA construction.

Calling this method will attempt to optimize all MemoryUses, if this has not happened yet for this MemorySSA instance. This should be done if you plan to query the clobbering access for most uses, or if you walk the def-use chain of uses.

Definition at line 2200 of file MemorySSA.cpp.

References llvm::MemorySSA::OptimizeUses::optimizeUses().

Referenced by llvm::GVNHoist::GVNHoist(), and llvm::MemorySSAPrinterPass::run().

◆ getAA()

AliasAnalysis & llvm::MemorySSA::getAA ( )
inline

◆ getBlockAccesses()

const AccessList * llvm::MemorySSA::getBlockAccesses ( const BasicBlock BB) const
inline

◆ getBlockDefs()

const DefsList * llvm::MemorySSA::getBlockDefs ( const BasicBlock BB) const
inline

Return the list of MemoryDef's and MemoryPhi's for a given basic block.

This list is not modifiable by the user.

Definition at line 767 of file MemorySSA.h.

Referenced by llvm::MemorySSAUpdater::insertUse(), pointerInvalidatedByBlock(), unswitchAllTrivialConditions(), verifyOrderingDominationAndDefUses(), and verifyPrevDefInPhis().

◆ getDomTree()

DominatorTree & llvm::MemorySSA::getDomTree ( ) const
inline

◆ getLiveOnEntryDef()

MemoryAccess * llvm::MemorySSA::getLiveOnEntryDef ( ) const
inline

◆ getMemoryAccess() [1/2]

MemoryPhi * llvm::MemorySSA::getMemoryAccess ( const BasicBlock BB) const
inline

Definition at line 723 of file MemorySSA.h.

◆ getMemoryAccess() [2/2]

MemoryUseOrDef * llvm::MemorySSA::getMemoryAccess ( const Instruction I) const
inline

Given a memory Mod/Ref'ing instruction, get the MemorySSA access associated with it.

If passed a basic block gets the memory phi node that exists for that block, if there is one. Otherwise, this will get a MemoryUseOrDef.

Definition at line 719 of file MemorySSA.h.

References I.

Referenced by buildPartialInvariantUnswitchConditionalBranch(), llvm::canSinkOrHoistInst(), llvm::MemorySSAUpdater::changeToUnreachable(), cloneInstructionInExitBlock(), llvm::MemorySSAWalker::getClobberingMemoryAccess(), llvm::MemorySSA::ClobberWalkerBase::getClobberingMemoryAccessBase(), getMatchingValue(), getNewDefiningAccessForClone(), llvm::hasPartialIVCondition(), llvm::MemorySSAUpdater::insertDef(), llvm::Loop::makeLoopInvariant(), llvm::MergeBlockIntoPredecessor(), llvm::MemorySSAUpdater::moveAllAfterMergeBlocks(), llvm::MemorySSAUpdater::moveAllAfterSpliceBlocks(), moveInstructionBefore(), llvm::MemorySSAUpdater::moveToPlace(), llvm::MemorySSAUpdater::removeBlocks(), llvm::MemorySSAUpdater::removeDuplicatePhiEdgesBetween(), llvm::MemorySSAUpdater::removeEdge(), llvm::MemorySSAUpdater::removeMemoryAccess(), runMoveAutoInit(), simplifyLoopInst(), sinkInstruction(), turnGuardIntoBranch(), llvm::MemorySSAUpdater::updateForClonedBlockIntoPred(), llvm::MemorySSAUpdater::updateForClonedLoop(), llvm::MemorySSAUpdater::updatePhisWhenInsertingUniqueBackedgeBlock(), usersDominator(), verifyOrderingDominationAndDefUses(), verifyPrevDefInPhis(), and llvm::MemorySSAUpdater::wireOldPredecessorsToNewImmediatePredecessor().

◆ getSkipSelfWalker()

MemorySSAWalker * MemorySSA::getSkipSelfWalker ( )

Definition at line 1603 of file MemorySSA.cpp.

Referenced by getClobberingMemoryAccess().

◆ getWalker()

MemorySSAWalker * MemorySSA::getWalker ( )

◆ getWritableBlockAccesses()

AccessList * llvm::MemorySSA::getWritableBlockAccesses ( const BasicBlock BB) const
inlineprotected

◆ getWritableBlockDefs()

DefsList * llvm::MemorySSA::getWritableBlockDefs ( const BasicBlock BB) const
inlineprotected

◆ insertIntoListsBefore()

void MemorySSA::insertIntoListsBefore ( MemoryAccess What,
const BasicBlock BB,
AccessList::iterator  InsertPt 
)
protected

◆ insertIntoListsForBlock()

void MemorySSA::insertIntoListsForBlock ( MemoryAccess NewAccess,
const BasicBlock BB,
InsertionPlace  Point 
)
protected

Definition at line 1618 of file MemorySSA.cpp.

References Beginning, and llvm::find_if_not().

Referenced by llvm::MemorySSAUpdater::createMemoryAccessInBB(), and moveTo().

◆ isLiveOnEntryDef()

bool llvm::MemorySSA::isLiveOnEntryDef ( const MemoryAccess MA) const
inline

Return true if MA represents the live on entry value.

Loads and stores from pointer arguments and other global values may be defined by memory operations that do not occur in the current function, so they may be live on entry to the function. MemorySSA represents such memory state by the live on entry definition, which is guaranteed to occur before any other memory access in the function.

Definition at line 739 of file MemorySSA.h.

Referenced by llvm::canSinkOrHoistInst(), checkClobberSanity(), dominates(), llvm::MemorySSA::ClobberWalkerBase::getClobberingMemoryAccessBase(), getNewDefiningAccessForClone(), hasUndefContents(), llvm::AMDGPU::isClobberedInFunction(), locallyDominates(), pointerInvalidatedByLoop(), and llvm::MemorySSAUpdater::removeMemoryAccess().

◆ locallyDominates()

bool MemorySSA::locallyDominates ( const MemoryAccess Dominator,
const MemoryAccess Dominatee 
) const

Given two memory accesses in the same basic block, determine whether MemoryAccess A dominates MemoryAccess B.

Determine, for two memory accesses in the same block, whether Dominator dominates Dominatee.

Returns
True if Dominator dominates Dominatee.

Definition at line 2142 of file MemorySSA.cpp.

References assert(), llvm::MemoryAccess::getBlock(), and isLiveOnEntryDef().

Referenced by dominates(), and pointerInvalidatedByBlock().

◆ moveTo() [1/2]

void MemorySSA::moveTo ( MemoryAccess What,
BasicBlock BB,
InsertionPlace  Point 
)
protected

◆ moveTo() [2/2]

void MemorySSA::moveTo ( MemoryUseOrDef What,
BasicBlock BB,
AccessList::iterator  Where 
)
protected

◆ print()

void MemorySSA::print ( raw_ostream OS) const

◆ removeFromLists()

void MemorySSA::removeFromLists ( MemoryAccess MA,
bool  ShouldDelete = true 
)
protected

Properly remove MA from all of MemorySSA's lists.

Because of the way the intrusive list and use lists work, it is important to do removal in the right order. ShouldDelete defaults to true, and will cause the memory access to also be deleted, not just removed.

Definition at line 1866 of file MemorySSA.cpp.

References llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::erase(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::find(), and llvm::MemoryAccess::getBlock().

Referenced by llvm::MemorySSAUpdater::removeBlocks(), and llvm::MemorySSAUpdater::removeMemoryAccess().

◆ removeFromLookups()

void MemorySSA::removeFromLookups ( MemoryAccess MA)
protected

◆ renamePass()

void llvm::MemorySSA::renamePass ( BasicBlock BB,
MemoryAccess IncomingVal,
SmallPtrSetImpl< BasicBlock * > &  Visited 
)
inlineprotected

◆ verifyDominationNumbers()

template<typename IterT >
void MemorySSA::verifyDominationNumbers ( IterT  Blocks) const
protected

Verify that all of the blocks we believe to have valid domination numbers actually have valid domination numbers.

Definition at line 1979 of file MemorySSA.cpp.

References assert(), Blocks, llvm::SmallPtrSetImpl< PtrType >::count(), llvm::SmallPtrSetImplBase::empty(), llvm::SmallPtrSetImpl< PtrType >::erase(), and getBlockAccesses().

Referenced by verifyMemorySSA().

◆ verifyMemorySSA()

void MemorySSA::verifyMemorySSA ( VerificationLevel  VL = VerificationLevel::Fast) const

◆ verifyOrderingDominationAndDefUses()

template<typename IterT >
void MemorySSA::verifyOrderingDominationAndDefUses ( IterT  Blocks,
VerificationLevel  VL = VerificationLevel::Fast 
) const
protected

Verify ordering: the order and existence of MemoryAccesses matches the order and existence of memory affecting instructions.

Verify domination: each definition dominates all of its uses. Verify def-uses: the immediate use information - walk all the memory accesses and verifying that, for each use, it appears in the appropriate def's use list

Definition at line 2021 of file MemorySSA.cpp.

References assert(), B, llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::MachineBasicBlock::begin(), Blocks, llvm::SmallVectorImpl< T >::clear(), DL, dominates(), llvm::SmallVectorTemplateCommon< T, typename >::end(), llvm::MachineBasicBlock::end(), Full, getBlockAccesses(), getBlockDefs(), llvm::MemoryUseOrDef::getDefiningAccess(), getMemoryAccess(), I, llvm::is_contained(), llvm::pred_size(), llvm::predecessors(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::SmallVectorBase< Size_T >::size(), llvm::MachineBasicBlock::size(), and llvm::Value::uses().

Referenced by verifyMemorySSA().

◆ verifyPrevDefInPhis()

template<typename IterT >
void MemorySSA::verifyPrevDefInPhis ( IterT  Blocks) const
protected

Friends And Related Function Documentation

◆ MemorySSAUpdater

friend class MemorySSAUpdater
friend

Definition at line 803 of file MemorySSA.h.


The documentation for this class was generated from the following files: