LLVM  6.0.0svn
Namespaces | Functions | Variables
ARC Optimization.

Namespaces

 llvm
 Compute iterated dominance frontiers using a linear time algorithm.
 

Functions

 STATISTIC (NumNoops, "Number of no-op objc calls eliminated")
 
 STATISTIC (NumPartialNoops, "Number of partially no-op objc calls eliminated")
 
 STATISTIC (NumAutoreleases,"Number of autoreleases converted to releases")
 
 STATISTIC (NumRets, "Number of return value forwarding " "retain+autoreleases eliminated")
 
 STATISTIC (NumRRs, "Number of retain+release paths eliminated")
 
 STATISTIC (NumPeeps, "Number of calls peephole-optimized")
 
 STATISTIC (NumRetainsBeforeOpt, "Number of retains before optimization")
 
 STATISTIC (NumReleasesBeforeOpt, "Number of releases before optimization")
 
 STATISTIC (NumRetainsAfterOpt, "Number of retains after optimization")
 
 STATISTIC (NumReleasesAfterOpt, "Number of releases after optimization")
 
 INITIALIZE_PASS_BEGIN (ObjCARCOpt, "objc-arc", "ObjC ARC optimization", false, false) INITIALIZE_PASS_END(ObjCARCOpt
 
static void CheckForUseCFGHazard (const Sequence SuccSSeq, const bool SuccSRRIKnownSafe, TopDownPtrState &S, bool &SomeSuccHasSame, bool &AllSuccsHaveSame, bool &NotAllSeqEqualButKnownSafe, bool &ShouldContinue)
 If we have a top down pointer in the S_Use state, make sure that there are no CFG hazards by checking the states of various bottom up pointers. More...
 
static void CheckForCanReleaseCFGHazard (const Sequence SuccSSeq, const bool SuccSRRIKnownSafe, TopDownPtrState &S, bool &SomeSuccHasSame, bool &AllSuccsHaveSame, bool &NotAllSeqEqualButKnownSafe)
 If we have a Top Down pointer in the S_CanRelease state, make sure that there are no CFG hazards by checking the states of various bottom up pointers. More...
 
static void ComputePostOrders (Function &F, SmallVectorImpl< BasicBlock *> &PostOrder, SmallVectorImpl< BasicBlock *> &ReverseCFGPostOrder, unsigned NoObjCARCExceptionsMDKind, DenseMap< const BasicBlock *, BBState > &BBStates)
 
static bool HasSafePathToPredecessorCall (const Value *Arg, Instruction *Retain, SmallPtrSetImpl< Instruction *> &DepInsts, SmallPtrSetImpl< const BasicBlock *> &Visited, ProvenanceAnalysis &PA)
 Check if there is a dependent call earlier that does not have anything in between the Retain and the call that can affect the reference count of their shared pointer argument. More...
 
static CallInstFindPredecessorRetainWithSafePath (const Value *Arg, BasicBlock *BB, Instruction *Autorelease, SmallPtrSetImpl< Instruction *> &DepInsts, SmallPtrSetImpl< const BasicBlock *> &Visited, ProvenanceAnalysis &PA)
 Find a dependent retain that precedes the given autorelease for which there is nothing in between the two instructions that can affect the ref count of Arg. More...
 
static CallInstFindPredecessorAutoreleaseWithSafePath (const Value *Arg, BasicBlock *BB, ReturnInst *Ret, SmallPtrSetImpl< Instruction *> &DepInsts, SmallPtrSetImpl< const BasicBlock *> &V, ProvenanceAnalysis &PA)
 Look for an ``autorelease'' instruction dependent on Arg such that there are no instructions dependent on Arg that need a positive ref count in between the autorelease and the ret. More...
 
raw_ostreamllvm::operator<< (raw_ostream &OS, BBState &BBState) LLVM_ATTRIBUTE_UNUSED
 
Passllvm::createObjCARCOptPass ()
 

Variables

objc arc
 
objc ObjC ARC optimization
 
objc ObjC ARC false
 
static const unsigned BBState::OverflowOccurredValue = 0xffffffff
 
static char ObjCARCOpt::ID = 0
 

Detailed Description

Function Documentation

◆ CheckForCanReleaseCFGHazard()

static void CheckForCanReleaseCFGHazard ( const Sequence  SuccSSeq,
const bool  SuccSRRIKnownSafe,
TopDownPtrState S,
bool SomeSuccHasSame,
bool AllSuccsHaveSame,
bool NotAllSeqEqualButKnownSafe 
)
static

If we have a Top Down pointer in the S_CanRelease state, make sure that there are no CFG hazards by checking the states of various bottom up pointers.

Definition at line 989 of file ObjCARCOpts.cpp.

References Arg, assert(), llvm::objcarc::AutoreleasepoolPop, llvm::objcarc::AutoreleasepoolPush, llvm::BasicBlock::back(), llvm::BasicBlock::begin(), CheckForUseCFGHazard(), llvm::objcarc::PtrState::ClearSequenceProgress(), llvm::dbgs(), DEBUG, E, llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::BasicBlock::end(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::find(), llvm::objcarc::GetARCInstKind(), llvm::objcarc::GetArgRCIdentityRoot(), llvm::objcarc::PtrState::GetRRInfo(), llvm::objcarc::PtrState::GetSeq(), llvm::objcarc::BottomUpPtrState::HandlePotentialAlterRefCount(), llvm::objcarc::TopDownPtrState::HandlePotentialAlterRefCount(), llvm::objcarc::BottomUpPtrState::HandlePotentialUse(), llvm::objcarc::TopDownPtrState::HandlePotentialUse(), I, llvm::objcarc::BottomUpPtrState::InitBottomUp(), llvm::objcarc::TopDownPtrState::InitTopDown(), llvm::objcarc::PtrState::IsKnownSafe(), llvm_unreachable, llvm::objcarc::TopDownPtrState::MatchWithRelease(), llvm::objcarc::BottomUpPtrState::MatchWithRetain(), MI, llvm::objcarc::None, llvm::objcarc::Release, llvm::objcarc::Retain, llvm::objcarc::RetainBlock, llvm::objcarc::RetainRV, llvm::objcarc::S_CanRelease, llvm::objcarc::S_MovableRelease, llvm::objcarc::S_None, llvm::objcarc::S_Release, llvm::objcarc::S_Retain, llvm::objcarc::S_Stop, llvm::objcarc::S_Use, llvm::objcarc::PtrState::SetCFGHazardAfflicted(), and SI.

◆ CheckForUseCFGHazard()

static void CheckForUseCFGHazard ( const Sequence  SuccSSeq,
const bool  SuccSRRIKnownSafe,
TopDownPtrState S,
bool SomeSuccHasSame,
bool AllSuccsHaveSame,
bool NotAllSeqEqualButKnownSafe,
bool ShouldContinue 
)
static

◆ ComputePostOrders()

static void ComputePostOrders ( Function F,
SmallVectorImpl< BasicBlock *> &  PostOrder,
SmallVectorImpl< BasicBlock *> &  ReverseCFGPostOrder,
unsigned  NoObjCARCExceptionsMDKind,
DenseMap< const BasicBlock *, BBState > &  BBStates 
)
static

The visited set, for doing DFS walks.

Definition at line 1350 of file ObjCARCOpts.cpp.

References Arg, assert(), llvm::objcarc::AutoreleasepoolPush, B, llvm::SmallVectorTemplateCommon< T >::back(), llvm::BasicBlock::back(), llvm::BlotMapVector< KeyT, ValueT >::begin(), llvm::BasicBlock::begin(), llvm::BlotMapVector< KeyT, ValueT >::blot(), llvm::objcarc::Call, llvm::objcarc::RRInfo::Calls, llvm::SmallPtrSetImplBase::clear(), llvm::objcarc::CopyWeak, llvm::SmallPtrSetImpl< PtrType >::count(), llvm::CallInst::Create(), llvm::dbgs(), DEBUG, llvm::objcarc::DestroyWeak, E, llvm::SmallVectorBase::empty(), llvm::BlotMapVector< KeyT, ValueT >::end(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::erase(), llvm::SmallPtrSetImpl< PtrType >::erase(), llvm::Instruction::eraseFromParent(), llvm::objcarc::EraseInstruction(), llvm::BlotMapVector< KeyT, ValueT >::find(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, KeyInfoT, BucketT >, KeyT, ValueT, KeyInfoT, BucketT >::find(), llvm::objcarc::GetARCInstKind(), llvm::CallInst::getArgOperand(), llvm::objcarc::GetArgRCIdentityRoot(), llvm::objcarc::GetBasicARCInstKind(), llvm::InstIterator< BB_t, BB_i_t, BI_t, II_t >::getBasicBlockIterator(), llvm::Type::getContext(), llvm::Function::getEntryBlock(), llvm::InstIterator< BB_t, BB_i_t, BI_t, II_t >::getInstructionIterator(), llvm::Type::getInt8Ty(), llvm::Instruction::getParent(), llvm::GlobalValue::getParent(), llvm::objcarc::GetRCIdentityRoot(), llvm::Value::getType(), llvm::PointerType::getUnqual(), I, llvm::objcarc::ImpreciseRelease, llvm::objcarc::InitWeak, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::inst_begin(), llvm::inst_end(), llvm::objcarc::IntrinsicUser, llvm::objcarc::RRInfo::IsTailCallRelease, llvm::objcarc::RRInfo::KnownSafe, llvm_unreachable, llvm::objcarc::LoadWeak, llvm::objcarc::LoadWeakRetained, llvm::MayAlias, llvm::objcarc::MoveWeak, llvm::MustAlias, llvm::NoAlias, llvm::objcarc::None, llvm::objcarc::NoObjCARCExceptions, llvm::PartialAlias, llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::pop_back(), llvm::SmallVectorImpl< T >::pop_back_val(), llvm::pred_begin(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), llvm::objcarc::Release, llvm::objcarc::RRInfo::ReleaseMetadata, llvm::Value::replaceAllUsesWith(), llvm::objcarc::Retain, llvm::reverse(), llvm::objcarc::RRInfo::ReverseInsertPts, llvm::CallInst::setDoesNotThrow(), llvm::Instruction::setMetadata(), llvm::CallInst::setTailCall(), llvm::objcarc::StoreWeak, llvm::Value::use_empty(), llvm::objcarc::User, and llvm::Value::users().

◆ createObjCARCOptPass()

objc ObjC ARC false Pass * llvm::createObjCARCOptPass ( )

Definition at line 563 of file ObjCARCOpts.cpp.

References llvm::AnalysisUsage::addRequired(), Arg, llvm::objcarc::Autorelease, llvm::objcarc::AutoreleasePoolBoundary, llvm::objcarc::AutoreleaseRV, llvm::BasicBlock::back(), llvm::BasicBlock::begin(), llvm::SmallPtrSetImpl< PtrType >::begin(), C, llvm::objcarc::Call, llvm::objcarc::ClaimRV, llvm::Instruction::clone(), llvm::objcarc::CopyWeak, llvm::CallInst::Create(), llvm::dbgs(), DEBUG, llvm::objcarc::DestroyWeak, llvm::dyn_cast(), E, llvm::SmallVectorBase::empty(), llvm::Instruction::eraseFromParent(), llvm::objcarc::EraseInstruction(), F(), llvm::objcarc::FindDependencies(), FindSingleUseIdentifiedObject(), llvm::MDNode::get(), llvm::UndefValue::get(), llvm::CallInst::getArgOperand(), llvm::objcarc::GetArgRCIdentityRoot(), llvm::objcarc::GetBasicARCInstKind(), llvm::Value::getContext(), llvm::PHINode::getIncomingBlock(), llvm::PHINode::getIncomingValue(), llvm::CallSiteBase< FunTy, BBTy, ValTy, UserTy, UseTy, InstrTy, CallTy, InvokeTy, IterTy >::getInstruction(), llvm::ilist_node_impl< OptionsT >::getIterator(), llvm::Instruction::getMetadata(), llvm::Constant::getNullValue(), llvm::PHINode::getNumIncomingValues(), llvm::Instruction::getParent(), llvm::objcarc::GetRCIdentityRoot(), llvm::Value::getType(), I, llvm::objcarc::ImpreciseRelease, llvm::objcarc::InitWeak, llvm::Instruction::insertBefore(), llvm::inst_begin(), llvm::inst_end(), llvm::objcarc::IsAlwaysTail(), llvm::objcarc::IsAutorelease(), llvm::objcarc::IsNeverTail(), llvm::objcarc::IsNoopInstruction(), llvm::objcarc::IsNoopOnNull(), llvm::objcarc::IsNoThrow(), llvm::objcarc::IsNullOrUndef(), llvm_unreachable, llvm::objcarc::LoadWeak, llvm::objcarc::LoadWeakRetained, llvm::objcarc::MoveWeak, llvm::objcarc::NeedsPositiveRetainCount, llvm::objcarc::None, llvm::objcarc::NoopCast, llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, isPodLike< T >::value >::push_back(), llvm::objcarc::Release, llvm::Value::replaceAllUsesWith(), llvm::objcarc::Retain, llvm::objcarc::RetainBlock, llvm::objcarc::RetainRV, llvm::CallInst::setArgOperand(), llvm::CallInst::setCalledFunction(), setDoesNotThrow(), llvm::Instruction::setMetadata(), llvm::AnalysisUsage::setPreservesCFG(), llvm::CallInst::setTailCall(), llvm::SmallPtrSetImplBase::size(), llvm::objcarc::StoreWeak, llvm::Value::use_empty(), Users, and llvm::Value::users().

◆ FindPredecessorAutoreleaseWithSafePath()

static CallInst* FindPredecessorAutoreleaseWithSafePath ( const Value Arg,
BasicBlock BB,
ReturnInst Ret,
SmallPtrSetImpl< Instruction *> &  DepInsts,
SmallPtrSetImpl< const BasicBlock *> &  V,
ProvenanceAnalysis PA 
)
static

◆ FindPredecessorRetainWithSafePath()

static CallInst* FindPredecessorRetainWithSafePath ( const Value Arg,
BasicBlock BB,
Instruction Autorelease,
SmallPtrSetImpl< Instruction *> &  DepInsts,
SmallPtrSetImpl< const BasicBlock *> &  Visited,
ProvenanceAnalysis PA 
)
static

Find a dependent retain that precedes the given autorelease for which there is nothing in between the two instructions that can affect the ref count of Arg.

Definition at line 1980 of file ObjCARCOpts.cpp.

References Arg, llvm::SmallPtrSetImpl< PtrType >::begin(), llvm::objcarc::CanChangeRetainCount, llvm::objcarc::FindDependencies(), llvm::objcarc::GetArgRCIdentityRoot(), llvm::objcarc::GetBasicARCInstKind(), llvm::objcarc::IsRetain(), llvm::objcarc::Retain, and llvm::SmallPtrSetImplBase::size().

Referenced by FindPredecessorAutoreleaseWithSafePath().

◆ HasSafePathToPredecessorCall()

static bool HasSafePathToPredecessorCall ( const Value Arg,
Instruction Retain,
SmallPtrSetImpl< Instruction *> &  DepInsts,
SmallPtrSetImpl< const BasicBlock *> &  Visited,
ProvenanceAnalysis PA 
)
static

Check if there is a dependent call earlier that does not have anything in between the Retain and the call that can affect the reference count of their shared pointer argument.

Note that Retain need not be in BB.

Definition at line 1956 of file ObjCARCOpts.cpp.

References llvm::objcarc::Call, llvm::objcarc::CallOrUser, llvm::objcarc::CanChangeRetainCount, llvm::objcarc::FindDependencies(), llvm::objcarc::GetBasicARCInstKind(), llvm::Instruction::getParent(), and llvm::objcarc::Retain.

Referenced by FindPredecessorAutoreleaseWithSafePath().

◆ INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN ( ObjCARCOpt  ,
"objc-arc ,
"ObjC ARC optimization ,
false  ,
false   
)

◆ operator<<()

raw_ostream & llvm::operator<< ( raw_ostream OS,
BBState &  BBState 
)

◆ STATISTIC() [1/10]

STATISTIC ( NumNoops  ,
"Number of no-op objc calls eliminated"   
)

◆ STATISTIC() [2/10]

STATISTIC ( NumPartialNoops  ,
"Number of partially no-op objc calls eliminated"   
)

◆ STATISTIC() [3/10]

STATISTIC ( NumAutoreleases  ,
"Number of autoreleases converted to releases"   
)

◆ STATISTIC() [4/10]

STATISTIC ( NumRets  ,
"Number of return value forwarding " "retain+autoreleases eliminated"   
)

◆ STATISTIC() [5/10]

STATISTIC ( NumRRs  ,
"Number of retain+release paths eliminated"   
)

◆ STATISTIC() [6/10]

STATISTIC ( NumPeeps  ,
"Number of calls peephole-optimized"   
)

◆ STATISTIC() [7/10]

STATISTIC ( NumRetainsBeforeOpt  ,
"Number of retains before optimization  
)

◆ STATISTIC() [8/10]

STATISTIC ( NumReleasesBeforeOpt  ,
"Number of releases before optimization  
)

◆ STATISTIC() [9/10]

STATISTIC ( NumRetainsAfterOpt  ,
"Number of retains after optimization  
)

◆ STATISTIC() [10/10]

STATISTIC ( NumReleasesAfterOpt  ,
"Number of releases after optimization  
)

Variable Documentation

◆ arc

objc arc

Definition at line 561 of file ObjCARCOpts.cpp.

◆ false

objc ObjC ARC false

Definition at line 561 of file ObjCARCOpts.cpp.

◆ ID

char ObjCARCOpt::ID = 0
static

Definition at line 546 of file ObjCARCOpts.cpp.

◆ optimization

objc ObjC ARC optimization

Definition at line 561 of file ObjCARCOpts.cpp.

◆ OverflowOccurredValue

const unsigned BBState::OverflowOccurredValue = 0xffffffff
static

Definition at line 203 of file ObjCARCOpts.cpp.