#include "llvm/CodeGen/RegisterScavenging.h"

Public Member Functions
	RegScavenger ()=default

void	assignRegToScavengingIndex (int FI, Register Reg, MachineInstr *Restore=nullptr)
	Record that `Reg` is in use at scavenging index `FI`.

void	enterBasicBlock (MachineBasicBlock &MBB)
	Start tracking liveness from the begin of basic block `MBB`.

void	enterBasicBlockEnd (MachineBasicBlock &MBB)
	Start tracking liveness from the end of basic block `MBB`.

void	forward ()
	Move the internal MBB iterator and update register states.

void	forward (MachineBasicBlock::iterator I)
	Move the internal MBB iterator and update register states until it has processed the specific iterator.

void	backward ()
	Update internal register state and move MBB iterator backwards.

void	backward (MachineBasicBlock::iterator I)
	Call backward() as long as the internal iterator does not point to `I`.

void	skipTo (MachineBasicBlock::iterator I)
	Move the internal MBB iterator but do not update register states.

MachineBasicBlock::iterator	getCurrentPosition () const

bool	isRegUsed (Register Reg, bool includeReserved=true) const
	Return if a specific register is currently used.

BitVector	getRegsAvailable (const TargetRegisterClass *RC)
	Return all available registers in the register class in Mask.

Register	FindUnusedReg (const TargetRegisterClass *RC) const
	Find an unused register of the specified register class.

void	addScavengingFrameIndex (int FI)
	Add a scavenging frame index.

bool	isScavengingFrameIndex (int FI) const
	Query whether a frame index is a scavenging frame index.

void	getScavengingFrameIndices (SmallVectorImpl< int > &A) const
	Get an array of scavenging frame indices.

Register	scavengeRegister (const TargetRegisterClass *RC, MachineBasicBlock::iterator I, int SPAdj, bool AllowSpill=true)
	Make a register of the specific register class available and do the appropriate bookkeeping.

Register	scavengeRegister (const TargetRegisterClass *RegClass, int SPAdj, bool AllowSpill=true)

Register	scavengeRegisterBackwards (const TargetRegisterClass &RC, MachineBasicBlock::iterator To, bool RestoreAfter, int SPAdj, bool AllowSpill=true)
	Make a register of the specific register class available from the current position backwards to the place before `To`.

void	setRegUsed (Register Reg, LaneBitmask LaneMask=LaneBitmask::getAll())
	Tell the scavenger a register is used.

Detailed Description

Definition at line 34 of file RegisterScavenging.h.

Constructor & Destructor Documentation

◆ RegScavenger()

llvm::RegScavenger::RegScavenger ( )

default

Member Function Documentation

◆ addScavengingFrameIndex()

void llvm::RegScavenger::addScavengingFrameIndex ( int FI )

inline

Add a scavenging frame index.

Definition at line 143 of file RegisterScavenging.h.

References llvm::SmallVectorTemplateBase< T, bool >::push_back().

Referenced by llvm::PPCFrameLowering::addScavengingSpillSlot(), llvm::AArch64FrameLowering::determineCalleeSaves(), llvm::ARMFrameLowering::determineCalleeSaves(), llvm::CSKYFrameLowering::determineCalleeSaves(), llvm::HexagonFrameLowering::determineCalleeSaves(), llvm::MipsSEFrameLowering::determineCalleeSaves(), llvm::ARCFrameLowering::processFunctionBeforeFrameFinalized(), llvm::LoongArchFrameLowering::processFunctionBeforeFrameFinalized(), llvm::RISCVFrameLowering::processFunctionBeforeFrameFinalized(), llvm::SystemZELFFrameLowering::processFunctionBeforeFrameFinalized(), llvm::SIFrameLowering::processFunctionBeforeFrameFinalized(), and llvm::XCoreFrameLowering::processFunctionBeforeFrameFinalized().

◆ assignRegToScavengingIndex()

void llvm::RegScavenger::assignRegToScavengingIndex	(	int	FI,
		Register	Reg,
		MachineInstr *	Restore = `nullptr`
	)

inline

Record that Reg is in use at scavenging index FI.

This is for targets which need to directly manage the spilling process, and need to update the scavenger's internal state. It's expected this be called a second time with Restore set to a non-null value, so that the externally inserted restore instruction resets the scavenged slot liveness when encountered.

Definition at line 79 of file RegisterScavenging.h.

References assert(), llvm_unreachable, and Reg.

Referenced by llvm::SGPRSpillBuilder::prepare(), and llvm::SGPRSpillBuilder::restore().

◆ backward() [1/2]

void RegScavenger::backward ( )

Update internal register state and move MBB iterator backwards.

Contrary to unprocess() this method gives precise results even in the absence of kill flags.

Definition at line 227 of file RegisterScavenging.cpp.

References assert(), llvm::MachineBasicBlock::begin(), I, MBB, MI, and llvm::LiveRegUnits::stepBackward().

Referenced by analyzeCompressibleUses(), backward(), indirectCopyToAGPR(), llvm::Mips16InstrInfo::loadImmediate(), llvm::AArch64FrameLowering::processFunctionBeforeFrameFinalized(), and scavengeFrameVirtualRegsInBlock().

◆ backward() [2/2]

void llvm::RegScavenger::backward ( MachineBasicBlock::iterator I )

inline

Call backward() as long as the internal iterator does not point to I.

Definition at line 118 of file RegisterScavenging.h.

References backward(), I, and MBBI.

◆ enterBasicBlock()

void RegScavenger::enterBasicBlock ( MachineBasicBlock & MBB )

Start tracking liveness from the begin of basic block MBB.

Definition at line 82 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::addLiveIns(), and MBB.

Referenced by llvm::RISCVFrameLowering::canUseAsPrologue(), and llvm::SIFrameLowering::processFunctionBeforeFrameFinalized().

◆ enterBasicBlockEnd()

void RegScavenger::enterBasicBlockEnd ( MachineBasicBlock & MBB )

Start tracking liveness from the end of basic block MBB.

Use backward() to move towards the beginning of the block. This is preferred to enterBasicBlock() and forward() because it does not depend on the presence of kill flags.

Definition at line 87 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::addLiveOuts(), llvm::MachineBasicBlock::empty(), llvm::MachineBasicBlock::end(), and MBB.

Referenced by analyzeCompressibleUses(), indirectCopyToAGPR(), llvm::SIInstrInfo::insertIndirectBranch(), llvm::LoongArchInstrInfo::insertIndirectBranch(), llvm::RISCVInstrInfo::insertIndirectBranch(), llvm::Mips16InstrInfo::loadImmediate(), llvm::AArch64FrameLowering::processFunctionBeforeFrameFinalized(), and scavengeFrameVirtualRegsInBlock().

◆ FindUnusedReg()

Register RegScavenger::FindUnusedReg ( const TargetRegisterClass * RC ) const

Find an unused register of the specified register class.

Return 0 if none is found.

Definition at line 254 of file RegisterScavenging.cpp.

References llvm::dbgs(), isRegUsed(), LLVM_DEBUG, and llvm::printReg().

Referenced by llvm::LanaiRegisterInfo::eliminateFrameIndex(), llvm::AArch64FrameLowering::processFunctionBeforeFrameFinalized(), and replaceFrameIndex().

◆ forward() [1/2]

void RegScavenger::forward ( )

Move the internal MBB iterator and update register states.

Definition at line 155 of file RegisterScavenging.cpp.

References assert(), llvm::MachineBasicBlock::begin(), llvm::MachineBasicBlock::end(), llvm::MachineBasicBlock::getParent(), I, isRegUsed(), llvm_unreachable, MBB, MI, llvm::none_of(), llvm::MCRegisterInfo::subregs(), llvm::MCRegisterInfo::superregs(), and llvm::MachineFunction::verify().

Referenced by forward().

◆ forward() [2/2]

void llvm::RegScavenger::forward ( MachineBasicBlock::iterator I )

inline

Move the internal MBB iterator and update register states until it has processed the specific iterator.

Definition at line 107 of file RegisterScavenging.h.

References forward(), I, and MBBI.

◆ getCurrentPosition()

MachineBasicBlock::iterator llvm::RegScavenger::getCurrentPosition ( ) const

inline

Definition at line 130 of file RegisterScavenging.h.

References MBBI.

◆ getRegsAvailable()

BitVector RegScavenger::getRegsAvailable ( const TargetRegisterClass * RC )

Return all available registers in the register class in Mask.

Definition at line 265 of file RegisterScavenging.cpp.

References llvm::MCRegisterInfo::getNumRegs(), and isRegUsed().

Referenced by llvm::PPCRegisterInfo::eliminateFrameIndex(), llvm::Mips16InstrInfo::loadImmediate(), and scavengeRegister().

◆ getScavengingFrameIndices()

void llvm::RegScavenger::getScavengingFrameIndices ( SmallVectorImpl< int > & A ) const

inline

Get an array of scavenging frame indices.

Definition at line 157 of file RegisterScavenging.h.

References A, and I.

◆ isRegUsed()

bool RegScavenger::isRegUsed	(	Register	Reg,
		bool	includeReserved = `true`
	)		const

Return if a specific register is currently used.

Definition at line 248 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::available().

Referenced by llvm::SIRegisterInfo::buildSpillLoadStore(), llvm::RISCVFrameLowering::canUseAsPrologue(), llvm::SIRegisterInfo::eliminateFrameIndex(), FindUnusedReg(), forward(), llvm::SIInstrInfo::getAddNoCarry(), getRegsAvailable(), llvm::SGPRSpillBuilder::prepare(), llvm::SGPRSpillBuilder::readWriteTmpVGPR(), and scavengeRegister().

◆ isScavengingFrameIndex()

bool llvm::RegScavenger::isScavengingFrameIndex ( int FI ) const

inline

Query whether a frame index is a scavenging frame index.

Definition at line 148 of file RegisterScavenging.h.

References SI.

Referenced by llvm::AArch64RegisterInfo::eliminateFrameIndex(), llvm::ARMBaseRegisterInfo::eliminateFrameIndex(), and llvm::ThumbRegisterInfo::eliminateFrameIndex().

◆ scavengeRegister() [1/2]

Register RegScavenger::scavengeRegister	(	const TargetRegisterClass *	RC,
		MachineBasicBlock::iterator	I,
		int	SPAdj,
		bool	AllowSpill = `true`
	)

Make a register of the specific register class available and do the appropriate bookkeeping.

SPAdj is the stack adjustment due to call frame, it's passed along to eliminateFrameIndex(). Returns the scavenged register. This is deprecated as it depends on the quality of the kill flags being present; Use scavengeRegisterBackwards() instead!

If AllowSpill is false, fail if a spill is required to make the register available, and return NoRegister.

Definition at line 522 of file RegisterScavenging.cpp.

References assert(), Available, llvm::dbgs(), llvm::TargetRegisterInfo::getAllocatableSet(), llvm::TargetRegisterClass::getRawAllocationOrder(), getRegsAvailable(), I, isRegUsed(), llvm::MCRegAliasIterator::isValid(), LLVM_DEBUG, MI, llvm::printReg(), llvm::BitVector::reset(), SI, and UseMI.

Referenced by llvm::SIRegisterInfo::buildSpillLoadStore(), llvm::SIRegisterInfo::eliminateFrameIndex(), llvm::SGPRSpillBuilder::prepare(), and scavengeRegister().

◆ scavengeRegister() [2/2]

Register llvm::RegScavenger::scavengeRegister	(	const TargetRegisterClass *	RegClass,
		int	SPAdj,
		bool	AllowSpill = `true`
	)

inline

Definition at line 175 of file RegisterScavenging.h.

References MBBI, and scavengeRegister().

◆ scavengeRegisterBackwards()

Register RegScavenger::scavengeRegisterBackwards	(	const TargetRegisterClass &	RC,
		MachineBasicBlock::iterator	To,
		bool	RestoreAfter,
		int	SPAdj,
		bool	AllowSpill = `true`
	)

Make a register of the specific register class available from the current position backwards to the place before To.

If RestoreAfter is true this includes the instruction following the current position. SPAdj is the stack adjustment due to call frame, it's passed along to eliminateFrameIndex(). Returns the scavenged register.

If AllowSpill is false, fail if a spill is required to make the register available, and return NoRegister.

Definition at line 590 of file RegisterScavenging.cpp.

References assert(), llvm::dbgs(), llvm::MachineBasicBlock::end(), findSurvivorBackwards(), llvm::MachineBasicBlock::getParent(), llvm::TargetRegisterClass::getRawAllocationOrder(), LLVM_DEBUG, MBB, P, llvm::printReg(), llvm::LiveRegUnits::removeReg(), and UseMI.

Referenced by analyzeCompressibleUses(), llvm::SIRegisterInfo::buildSpillLoadStore(), llvm::LanaiRegisterInfo::eliminateFrameIndex(), llvm::SIInstrInfo::getAddNoCarry(), indirectCopyToAGPR(), InsertFPConstInst(), llvm::SIInstrInfo::insertIndirectBranch(), llvm::LoongArchInstrInfo::insertIndirectBranch(), llvm::RISCVInstrInfo::insertIndirectBranch(), InsertSPConstInst(), replaceFrameIndex(), and scavengeVReg().

◆ setRegUsed()

void RegScavenger::setRegUsed	(	Register	Reg,
		LaneBitmask	LaneMask = `LaneBitmask::getAll()`
	)

Tell the scavenger a register is used.

Definition at line 51 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::addRegMasked().

Referenced by llvm::SIRegisterInfo::buildSpillLoadStore(), indirectCopyToAGPR(), InsertFPConstInst(), llvm::SIInstrInfo::insertIndirectBranch(), llvm::LoongArchInstrInfo::insertIndirectBranch(), llvm::RISCVInstrInfo::insertIndirectBranch(), InsertSPConstInst(), llvm::SGPRSpillBuilder::prepare(), replaceFrameIndex(), and scavengeFrameVirtualRegsInBlock().

◆ skipTo()

void llvm::RegScavenger::skipTo ( MachineBasicBlock::iterator I )

inline

Move the internal MBB iterator but do not update register states.

Definition at line 124 of file RegisterScavenging.h.

References I, and MBBI.

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

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

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ RegScavenger()

Member Function Documentation

◆ addScavengingFrameIndex()

◆ assignRegToScavengingIndex()

◆ backward() [1/2]

◆ backward() [2/2]

◆ enterBasicBlock()

◆ enterBasicBlockEnd()

◆ FindUnusedReg()

◆ forward() [1/2]

◆ forward() [2/2]

◆ getCurrentPosition()

◆ getRegsAvailable()

◆ getScavengingFrameIndices()

◆ isRegUsed()

◆ isScavengingFrameIndex()

◆ scavengeRegister() [1/2]

◆ scavengeRegister() [2/2]

◆ scavengeRegisterBackwards()

◆ setRegUsed()

◆ skipTo()