This class provides the reaching def analysis. More...

#include "llvm/CodeGen/ReachingDefAnalysis.h"

Inheritance diagram for llvm::ReachingDefAnalysis:

Public Member Functions
	ReachingDefAnalysis ()
void	releaseMemory () override
	releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memory when it is no longer needed.
void	getAnalysisUsage (AnalysisUsage &AU) const override
	getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
void	printAllReachingDefs (MachineFunction &MF)
bool	runOnMachineFunction (MachineFunction &MF) override
	runOnMachineFunction - This method must be overloaded to perform the desired machine code transformation or analysis.
MachineFunctionProperties	getRequiredProperties () const override
void	reset ()
	Re-run the analysis.
void	init ()
	Initialize data structures.
void	traverse ()
	Traverse the machine function, mapping definitions.
int	getReachingDef (MachineInstr *MI, Register Reg) const
	Provides the instruction id of the closest reaching def instruction of Reg that reaches MI, relative to the begining of MI's basic block.
bool	hasSameReachingDef (MachineInstr A, MachineInstr B, Register Reg) const
	Return whether A and B use the same def of Reg.
bool	isReachingDefLiveOut (MachineInstr *MI, Register Reg) const
	Return whether the reaching def for MI also is live out of its parent block.
MachineInstr *	getLocalLiveOutMIDef (MachineBasicBlock *MBB, Register Reg) const
	Return the local MI that produces the live out value for Reg, or nullptr for a non-live out or non-local def.
MachineInstr *	getUniqueReachingMIDef (MachineInstr *MI, Register Reg) const
	If a single MachineInstr creates the reaching definition, then return it.
MachineInstr *	getMIOperand (MachineInstr *MI, unsigned Idx) const
	If a single MachineInstr creates the reaching definition, for MIs operand at Idx, then return it.
MachineInstr *	getMIOperand (MachineInstr *MI, MachineOperand &MO) const
	If a single MachineInstr creates the reaching definition, for MIs MO, then return it.
bool	hasLocalDefBefore (MachineInstr *MI, Register Reg) const
	Provide whether the register has been defined in the same basic block as, and before, MI.
bool	isRegUsedAfter (MachineInstr *MI, Register Reg) const
	Return whether the given register is used after MI, whether it's a local use or a live out.
bool	isRegDefinedAfter (MachineInstr *MI, Register Reg) const
	Return whether the given register is defined after MI.
int	getClearance (MachineInstr *MI, Register Reg) const
	Provides the clearance - the number of instructions since the closest reaching def instuction of Reg that reaches MI.
void	getReachingLocalUses (MachineInstr *MI, Register Reg, InstSet &Uses) const
	Provides the uses, in the same block as MI, of register that MI defines.
void	getLiveOuts (MachineBasicBlock *MBB, Register Reg, InstSet &Defs, BlockSet &VisitedBBs) const
	Search MBB for a definition of Reg and insert it into Defs.
void	getLiveOuts (MachineBasicBlock *MBB, Register Reg, InstSet &Defs) const
bool	getLiveInUses (MachineBasicBlock *MBB, Register Reg, InstSet &Uses) const
	For the given block, collect the instructions that use the live-in value of the provided register.
void	getGlobalUses (MachineInstr *MI, Register Reg, InstSet &Uses) const
	Collect the users of the value stored in Reg, which is defined by MI.
void	getGlobalReachingDefs (MachineInstr *MI, Register Reg, InstSet &Defs) const
	Collect all possible definitions of the value stored in Reg, which is used by MI.
bool	isSafeToMoveForwards (MachineInstr From, MachineInstr To) const
	Return whether From can be moved forwards to just before To.
bool	isSafeToMoveBackwards (MachineInstr From, MachineInstr To) const
	Return whether From can be moved backwards to just after To.
void	collectKilledOperands (MachineInstr *MI, InstSet &Dead) const
	Assuming MI is dead, recursively search the incoming operands which are killed by MI and collect those that would become dead.
bool	isSafeToRemove (MachineInstr *MI, InstSet &ToRemove) const
	Return whether removing this instruction will have no effect on the program, returning the redundant use-def chain.
bool	isSafeToRemove (MachineInstr *MI, InstSet &ToRemove, InstSet &Ignore) const
	Return whether removing this instruction will have no effect on the program, ignoring the possible effects on some instructions, returning the redundant use-def chain.
bool	isSafeToDefRegAt (MachineInstr *MI, Register Reg) const
	Return whether a MachineInstr could be inserted at MI and safely define the given register without affecting the program.
bool	isSafeToDefRegAt (MachineInstr *MI, Register Reg, InstSet &Ignore) const
	Return whether a MachineInstr could be inserted at MI and safely define the given register without affecting the program, ignoring any effects on the provided instructions.
Public Member Functions inherited from llvm::MachineFunctionPass
bool	doInitialization (Module &) override
	doInitialization - Virtual method overridden by subclasses to do any necessary initialization before any pass is run.
Public Member Functions inherited from llvm::FunctionPass
	FunctionPass (char &pid)
void	assignPassManager (PMStack &PMS, PassManagerType T) override
	Find appropriate Function Pass Manager or Call Graph Pass Manager in the PM Stack and add self into that manager.
PassManagerType	getPotentialPassManagerType () const override
	Return what kind of Pass Manager can manage this pass.
Public Member Functions inherited from llvm::Pass
	Pass (PassKind K, char &pid)
	Pass (const Pass &)=delete
Pass &	operator= (const Pass &)=delete
virtual	~Pass ()
PassKind	getPassKind () const
virtual StringRef	getPassName () const
	getPassName - Return a nice clean name for a pass.
StringRef	getPassArgument () const
	Return a nice clean name for a pass corresponding to that used to enable the pass in opt.
AnalysisID	getPassID () const
	getPassID - Return the PassID number that corresponds to this pass.
virtual bool	doFinalization (Module &)
	doFinalization - Virtual method overriden by subclasses to do any necessary clean up after all passes have run.
virtual void	print (raw_ostream &OS, const Module *M) const
	print - Print out the internal state of the pass.
void	dump () const
virtual void	preparePassManager (PMStack &)
	Check if available pass managers are suitable for this pass or not.
void	setResolver (AnalysisResolver *AR)
AnalysisResolver *	getResolver () const
virtual ImmutablePass *	getAsImmutablePass ()
virtual PMDataManager *	getAsPMDataManager ()
virtual void	verifyAnalysis () const
	verifyAnalysis() - This member can be implemented by a analysis pass to check state of analysis information.
virtual void	dumpPassStructure (unsigned Offset=0)
template<typename AnalysisType>
AnalysisType *	getAnalysisIfAvailable () const
	getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to get analysis information that might be around, for example to update it.
bool	mustPreserveAnalysisID (char &AID) const
	mustPreserveAnalysisID - This method serves the same function as getAnalysisIfAvailable, but works if you just have an AnalysisID.
template<typename AnalysisType>
AnalysisType &	getAnalysis () const
	getAnalysis<AnalysisType>() - This function is used by subclasses to get to the analysis information that they claim to use by overriding the getAnalysisUsage function.
template<typename AnalysisType>
AnalysisType &	getAnalysis (Function &F, bool *Changed=nullptr)
	getAnalysis<AnalysisType>() - This function is used by subclasses to get to the analysis information that they claim to use by overriding the getAnalysisUsage function.
template<typename AnalysisType>
AnalysisType &	getAnalysisID (AnalysisID PI) const
template<typename AnalysisType>
AnalysisType &	getAnalysisID (AnalysisID PI, Function &F, bool *Changed=nullptr)

Static Public Attributes
static char	ID = 0

Additional Inherited Members
Static Public Member Functions inherited from llvm::Pass
static const PassInfo *	lookupPassInfo (const void *TI)
static const PassInfo *	lookupPassInfo (StringRef Arg)
static Pass *	createPass (AnalysisID ID)
Protected Member Functions inherited from llvm::MachineFunctionPass
	MachineFunctionPass (char &ID)
virtual MachineFunctionProperties	getSetProperties () const
virtual MachineFunctionProperties	getClearedProperties () const
Protected Member Functions inherited from llvm::FunctionPass
bool	skipFunction (const Function &F) const
	Optional passes call this function to check whether the pass should be skipped.

Detailed Description

This class provides the reaching def analysis.

Definition at line 113 of file ReachingDefAnalysis.h.

Constructor & Destructor Documentation

◆ ReachingDefAnalysis()

llvm::ReachingDefAnalysis::ReachingDefAnalysis ( )

inline

Definition at line 161 of file ReachingDefAnalysis.h.

References llvm::PassRegistry::getPassRegistry(), ID, llvm::initializeReachingDefAnalysisPass(), and llvm::MachineFunctionPass::MachineFunctionPass().

Member Function Documentation

◆ collectKilledOperands()

void ReachingDefAnalysis::collectKilledOperands	(	MachineInstr *	MI,
		InstSet &	Dead ) const

Assuming MI is dead, recursively search the incoming operands which are killed by MI and collect those that would become dead.

Definition at line 736 of file ReachingDefAnalysis.cpp.

References collectKilledOperands(), getGlobalUses(), getMIOperand(), IsDead, isValidRegDef(), isValidRegUse(), mayHaveSideEffects(), MI, llvm::set_is_subset(), and Uses.

Referenced by collectKilledOperands().

◆ getAnalysisUsage()

void llvm::ReachingDefAnalysis::getAnalysisUsage ( AnalysisUsage & AU ) const

inlineoverridevirtual

getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.

For MachineFunctionPasses, calling AU.preservesCFG() indicates that the pass does not modify the MachineBasicBlock CFG.

Reimplemented from llvm::MachineFunctionPass.

Definition at line 166 of file ReachingDefAnalysis.h.

References llvm::MachineFunctionPass::getAnalysisUsage(), and llvm::AnalysisUsage::setPreservesAll().

◆ getClearance()

int ReachingDefAnalysis::getClearance	(	MachineInstr *	MI,
		Register	Reg ) const

Provides the clearance - the number of instructions since the closest reaching def instuction of Reg that reaches MI.

Definition at line 407 of file ReachingDefAnalysis.cpp.

References assert(), getReachingDef(), and MI.

◆ getGlobalReachingDefs()

void ReachingDefAnalysis::getGlobalReachingDefs	(	MachineInstr *	MI,
		Register	Reg,
		InstSet &	Defs ) const

Collect all possible definitions of the value stored in Reg, which is used by MI.

Definition at line 484 of file ReachingDefAnalysis.cpp.

References getLiveOuts(), getUniqueReachingMIDef(), llvm::SmallPtrSetImpl< PtrType >::insert(), MBB, and MI.

Referenced by printAllReachingDefs().

◆ getGlobalUses()

void ReachingDefAnalysis::getGlobalUses	(	MachineInstr *	MI,
		Register	Reg,
		InstSet &	Uses ) const

Collect the users of the value stored in Reg, which is defined by MI.

Definition at line 459 of file ReachingDefAnalysis.cpp.

References llvm::append_range(), llvm::SmallPtrSetImpl< PtrType >::count(), llvm::SmallVectorTemplateCommon< T, typename >::empty(), getLiveInUses(), getLocalLiveOutMIDef(), getReachingLocalUses(), llvm::SmallPtrSetImpl< PtrType >::insert(), MBB, MI, llvm::SmallVectorImpl< T >::pop_back_val(), and Uses.

Referenced by collectKilledOperands(), and isSafeToDefRegAt().

◆ getLiveInUses()

bool ReachingDefAnalysis::getLiveInUses	(	MachineBasicBlock *	MBB,
		Register	Reg,
		InstSet &	Uses ) const

For the given block, collect the instructions that use the live-in value of the provided register.

Return whether the value is still live on exit.

Definition at line 441 of file ReachingDefAnalysis.cpp.

References getReachingDef(), llvm::instructionsWithoutDebug(), isReachingDefLiveOut(), isValidRegUseOf(), llvm::Last, MBB, MI, and Uses.

Referenced by getGlobalUses().

◆ getLiveOuts() [1/2]

void ReachingDefAnalysis::getLiveOuts	(	MachineBasicBlock *	MBB,
		Register	Reg,
		InstSet &	Defs ) const

Definition at line 495 of file ReachingDefAnalysis.cpp.

References getLiveOuts(), and MBB.

◆ getLiveOuts() [2/2]

void ReachingDefAnalysis::getLiveOuts	(	MachineBasicBlock *	MBB,
		Register	Reg,
		InstSet &	Defs,
		BlockSet &	VisitedBBs ) const

Search MBB for a definition of Reg and insert it into Defs.

If no definition is found, recursively search the predecessor blocks for them.

Definition at line 501 of file ReachingDefAnalysis.cpp.

References llvm::SmallPtrSetImpl< PtrType >::count(), getLiveOuts(), getLocalLiveOutMIDef(), llvm::SmallPtrSetImpl< PtrType >::insert(), and MBB.

Referenced by getGlobalReachingDefs(), getLiveOuts(), getLiveOuts(), and getUniqueReachingMIDef().

◆ getLocalLiveOutMIDef()

MachineInstr * ReachingDefAnalysis::getLocalLiveOutMIDef	(	MachineBasicBlock *	MBB,
		Register	Reg ) const

Return the local MI that produces the live out value for Reg, or nullptr for a non-live out or non-local def.

Definition at line 607 of file ReachingDefAnalysis.cpp.

References getReachingDef(), isFIDef(), isValidRegDefOf(), llvm::Last, and MBB.

Referenced by getGlobalUses(), getLiveOuts(), and isRegDefinedAfter().

◆ getMIOperand() [1/2]

MachineInstr * ReachingDefAnalysis::getMIOperand	(	MachineInstr *	MI,
		MachineOperand &	MO ) const

If a single MachineInstr creates the reaching definition, for MIs MO, then return it.

Otherwise return null.

Definition at line 546 of file ReachingDefAnalysis.cpp.

References assert(), llvm::MachineOperand::getReg(), getUniqueReachingMIDef(), llvm::MachineOperand::isReg(), and MI.

◆ getMIOperand() [2/2]

MachineInstr * ReachingDefAnalysis::getMIOperand	(	MachineInstr *	MI,
		unsigned	Idx ) const

If a single MachineInstr creates the reaching definition, for MIs operand at Idx, then return it.

Otherwise return null.

Definition at line 540 of file ReachingDefAnalysis.cpp.

References assert(), getUniqueReachingMIDef(), and MI.

Referenced by collectKilledOperands().

◆ getReachingDef()

int ReachingDefAnalysis::getReachingDef	(	MachineInstr *	MI,
		Register	Reg ) const

Provides the instruction id of the closest reaching def instruction of Reg that reaches MI, relative to the begining of MI's basic block.

Note that Reg may represent a stack slot.

Definition at line 334 of file ReachingDefAnalysis.cpp.

References assert(), Lookup(), and MI.

Referenced by getClearance(), getLiveInUses(), getLocalLiveOutMIDef(), hasLocalDefBefore(), hasSameReachingDef(), isReachingDefLiveOut(), and isRegDefinedAfter().

◆ getReachingLocalUses()

void ReachingDefAnalysis::getReachingLocalUses	(	MachineInstr *	MI,
		Register	Reg,
		InstSet &	Uses ) const

Provides the uses, in the same block as MI, of register that MI defines.

This does not consider live-outs.

Definition at line 417 of file ReachingDefAnalysis.cpp.

References isValidRegUseOf(), MBB, MI, and Uses.

Referenced by getGlobalUses().

◆ getRequiredProperties()

MachineFunctionProperties llvm::ReachingDefAnalysis::getRequiredProperties ( ) const

inlineoverridevirtual

Reimplemented from llvm::MachineFunctionPass.

Definition at line 174 of file ReachingDefAnalysis.h.

◆ getUniqueReachingMIDef()

MachineInstr * ReachingDefAnalysis::getUniqueReachingMIDef	(	MachineInstr *	MI,
		Register	Reg ) const

If a single MachineInstr creates the reaching definition, then return it.

Otherwise return null.

Definition at line 520 of file ReachingDefAnalysis.cpp.

References getLiveOuts(), MI, and llvm::MachineBasicBlock::predecessors().

Referenced by getGlobalReachingDefs(), getMIOperand(), and getMIOperand().

◆ hasLocalDefBefore()

bool ReachingDefAnalysis::hasLocalDefBefore	(	MachineInstr *	MI,
		Register	Reg ) const

Provide whether the register has been defined in the same basic block as, and before, MI.

Definition at line 412 of file ReachingDefAnalysis.cpp.

References getReachingDef(), and MI.

◆ hasSameReachingDef()

bool ReachingDefAnalysis::hasSameReachingDef	(	MachineInstr *	A,
		MachineInstr *	B,
		Register	Reg ) const

Return whether A and B use the same def of Reg.

Definition at line 377 of file ReachingDefAnalysis.cpp.

References A(), B(), and getReachingDef().

◆ init()

void ReachingDefAnalysis::init ( )

Initialize data structures.

Definition at line 304 of file ReachingDefAnalysis.cpp.

References llvm::LoopTraversal::traverse().

Referenced by reset(), and runOnMachineFunction().

◆ isReachingDefLiveOut()

bool ReachingDefAnalysis::isReachingDefLiveOut	(	MachineInstr *	MI,
		Register	Reg ) const

Return whether the reaching def for MI also is live out of its parent block.

Definition at line 586 of file ReachingDefAnalysis.cpp.

References getReachingDef(), isValidRegDefOf(), llvm::Last, MBB, and MI.

Referenced by getLiveInUses().

◆ isRegDefinedAfter()

bool ReachingDefAnalysis::isRegDefinedAfter	(	MachineInstr *	MI,
		Register	Reg ) const

Return whether the given register is defined after MI.

Definition at line 572 of file ReachingDefAnalysis.cpp.

References getLocalLiveOutMIDef(), getReachingDef(), llvm::Last, MBB, and MI.

Referenced by isSafeToDefRegAt().

◆ isRegUsedAfter()

bool ReachingDefAnalysis::isRegUsedAfter	(	MachineInstr *	MI,
		Register	Reg ) const

Return whether the given register is used after MI, whether it's a local use or a live out.

Definition at line 552 of file ReachingDefAnalysis.cpp.

References llvm::instructionsWithoutDebug(), llvm::Last, MBB, and MI.

Referenced by isSafeToDefRegAt().

◆ isSafeToDefRegAt() [1/2]

bool ReachingDefAnalysis::isSafeToDefRegAt	(	MachineInstr *	MI,
		Register	Reg ) const

Return whether a MachineInstr could be inserted at MI and safely define the given register without affecting the program.

Definition at line 768 of file ReachingDefAnalysis.cpp.

References Ignore, isSafeToDefRegAt(), and MI.

Referenced by isSafeToDefRegAt().

◆ isSafeToDefRegAt() [2/2]

bool ReachingDefAnalysis::isSafeToDefRegAt	(	MachineInstr *	MI,
		Register	Reg,
		InstSet &	Ignore ) const

Return whether a MachineInstr could be inserted at MI and safely define the given register without affecting the program, ignoring any effects on the provided instructions.

Definition at line 774 of file ReachingDefAnalysis.cpp.

References getGlobalUses(), I, Ignore, isRegDefinedAfter(), isRegUsedAfter(), isValidRegDefOf(), MBB, MI, llvm::set_is_subset(), and Uses.

◆ isSafeToMoveBackwards()

bool ReachingDefAnalysis::isSafeToMoveBackwards	(	MachineInstr *	From,
		MachineInstr *	To ) const

Return whether From can be moved backwards to just after To.

Definition at line 682 of file ReachingDefAnalysis.cpp.

References llvm::MachineInstr::getParent(), I, and llvm::MachineBasicBlock::rend().

◆ isSafeToMoveForwards()

bool ReachingDefAnalysis::isSafeToMoveForwards	(	MachineInstr *	From,
		MachineInstr *	To ) const

Return whether From can be moved forwards to just before To.

Definition at line 672 of file ReachingDefAnalysis.cpp.

References llvm::MachineBasicBlock::end(), llvm::MachineInstr::getParent(), and I.

◆ isSafeToRemove() [1/2]

bool ReachingDefAnalysis::isSafeToRemove	(	MachineInstr *	MI,
		InstSet &	ToRemove ) const

Return whether removing this instruction will have no effect on the program, returning the redundant use-def chain.

Definition at line 692 of file ReachingDefAnalysis.cpp.

References Ignore, isSafeToRemove(), MI, and ToRemove.

Referenced by isSafeToRemove(), and isSafeToRemove().

◆ isSafeToRemove() [2/2]

bool ReachingDefAnalysis::isSafeToRemove	(	MachineInstr *	MI,
		InstSet &	ToRemove,
		InstSet &	Ignore ) const

Return whether removing this instruction will have no effect on the program, ignoring the possible effects on some instructions, returning the redundant use-def chain.

Definition at line 700 of file ReachingDefAnalysis.cpp.

References Ignore, isSafeToRemove(), MI, and ToRemove.

◆ printAllReachingDefs()

void ReachingDefAnalysis::printAllReachingDefs ( MachineFunction & MF )

Definition at line 235 of file ReachingDefAnalysis.cpp.

References assert(), llvm::SmallPtrSetImplBase::clear(), llvm::dbgs(), getGlobalReachingDefs(), llvm::Register::index2StackSlot(), MBB, MI, llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::sort().

Referenced by runOnMachineFunction().

◆ releaseMemory()

void ReachingDefAnalysis::releaseMemory ( )

overridevirtual

releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memory when it is no longer needed.

The default behavior of passes is to hold onto memory for the entire duration of their lifetime (which is the entire compile time). For pipelined passes, this is not a big deal because that memory gets recycled every time the pass is invoked on another program unit. For IP passes, it is more important to free memory when it is unused.

Optionally implement this function to release pass memory when it is no longer used.

Reimplemented from llvm::Pass.

Definition at line 289 of file ReachingDefAnalysis.cpp.

Referenced by reset().

◆ reset()

void ReachingDefAnalysis::reset ( )

Re-run the analysis.

Definition at line 298 of file ReachingDefAnalysis.cpp.

References init(), releaseMemory(), and traverse().

◆ runOnMachineFunction()

bool ReachingDefAnalysis::runOnMachineFunction ( MachineFunction & MF )

overridevirtual

runOnMachineFunction - This method must be overloaded to perform the desired machine code transformation or analysis.

Implements llvm::MachineFunctionPass.

Definition at line 276 of file ReachingDefAnalysis.cpp.

References llvm::dbgs(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::TargetSubtargetInfo::getRegisterInfo(), init(), LLVM_DEBUG, PrintAllReachingDefs, printAllReachingDefs(), and traverse().

◆ traverse()

void ReachingDefAnalysis::traverse ( )

Traverse the machine function, mapping definitions.

Definition at line 315 of file ReachingDefAnalysis.cpp.

References assert().

Referenced by reset(), and runOnMachineFunction().

Member Data Documentation

◆ ID

char ReachingDefAnalysis::ID = 0

static

Definition at line 159 of file ReachingDefAnalysis.h.

Referenced by ReachingDefAnalysis().

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

include/llvm/CodeGen/ReachingDefAnalysis.h
lib/CodeGen/ReachingDefAnalysis.cpp

Public Member Functions

Static Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ReachingDefAnalysis()

Member Function Documentation

◆ collectKilledOperands()

◆ getAnalysisUsage()

◆ getClearance()

◆ getGlobalReachingDefs()

◆ getGlobalUses()

◆ getLiveInUses()

◆ getLiveOuts() [1/2]

◆ getLiveOuts() [2/2]

◆ getLocalLiveOutMIDef()

◆ getMIOperand() [1/2]

◆ getMIOperand() [2/2]

◆ getReachingDef()

◆ getReachingLocalUses()

◆ getRequiredProperties()

◆ getUniqueReachingMIDef()

◆ hasLocalDefBefore()

◆ hasSameReachingDef()

◆ init()

◆ isReachingDefLiveOut()

◆ isRegDefinedAfter()

◆ isRegUsedAfter()

◆ isSafeToDefRegAt() [1/2]

◆ isSafeToDefRegAt() [2/2]

◆ isSafeToMoveBackwards()

◆ isSafeToMoveForwards()

◆ isSafeToRemove() [1/2]

◆ isSafeToRemove() [2/2]

◆ printAllReachingDefs()

◆ releaseMemory()

◆ reset()

◆ runOnMachineFunction()

◆ traverse()

Member Data Documentation

◆ ID