#include "llvm/CodeGen/RegisterScavenging.h"

Public Member Functions
	RegScavenger ()=default

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

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

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

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

void	unprocess ()
	Invert the behavior of forward() on the current instruction (undo the changes to the available registers made by forward()). More...

void	unprocess (MachineBasicBlock::iterator I)
	Unprocess instructions until you reach the provided iterator. More...

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

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

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

MachineBasicBlock::iterator	getCurrentPosition () const

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

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

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

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

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

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

unsigned	scavengeRegister (const TargetRegisterClass *RC, MachineBasicBlock::iterator I, int SPAdj)
	Make a register of the specific register class available and do the appropriate bookkeeping. More...

unsigned	scavengeRegister (const TargetRegisterClass *RegClass, int SPAdj)

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

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

Detailed Description

Definition at line 35 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 133 of file RegisterScavenging.h.

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

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

◆ 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 261 of file RegisterScavenging.cpp.

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

Referenced by backward(), llvm::AArch64FrameLowering::processFunctionBeforeFrameFinalized(), scavengeFrameVirtualRegsInBlock(), and unprocess().

◆ 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 108 of file RegisterScavenging.h.

References backward().

◆ enterBasicBlock()

void RegScavenger::enterBasicBlock ( MachineBasicBlock & MBB )

Start tracking liveness from the begin of basic block MBB.

Definition at line 84 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::addLiveIns(), and llvm::cl::init().

Referenced by llvm::SIInstrInfo::calculateLDSSpillAddress(), INITIALIZE_PASS(), llvm::Mips16InstrInfo::loadImmediate(), and llvm::PPCFrameLowering::replaceFPWithRealFP().

◆ 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 89 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::addLiveOuts(), addRegUnits(), assert(), llvm::MachineBasicBlock::begin(), llvm::BitVector::clear(), llvm::MachineBasicBlock::end(), llvm::cl::init(), llvm::MachineInstr::isDebugInstr(), llvm::TargetRegisterInfo::isPhysicalRegister(), llvm::MCRegisterInfo::DiffListIterator::isValid(), llvm::MCRegUnitRootIterator::isValid(), MI, llvm::MachineInstr::operands(), Reg, llvm::BitVector::reset(), llvm::BitVector::set(), and TRI.

Referenced by llvm::RISCVInstrInfo::insertIndirectBranch(), llvm::SIInstrInfo::insertIndirectBranch(), llvm::AArch64FrameLowering::processFunctionBeforeFrameFinalized(), and scavengeFrameVirtualRegsInBlock().

◆ FindUnusedReg()

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

Find an unused register of the specified register class.

Return 0 if none is found.

Definition at line 288 of file RegisterScavenging.cpp.

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

Referenced by buildMUBUFOffsetLoadStore(), llvm::LanaiRegisterInfo::eliminateFrameIndex(), getCurrentPosition(), INITIALIZE_PASS(), llvm::AArch64FrameLowering::processFunctionBeforeFrameFinalized(), and ReplaceFrameIndex().

◆ forward() [1/2]

void RegScavenger::forward ( )

Move the internal MBB iterator and update register states.

Definition at line 176 of file RegisterScavenging.cpp.

References assert(), llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::MachineBasicBlock::begin(), llvm::SmallVectorTemplateCommon< T, typename >::end(), llvm::MachineBasicBlock::end(), llvm::MachineBasicBlock::getParent(), I, llvm::ARM_PROC::IE, llvm::TargetRegisterInfo::isPhysicalRegister(), isRegUsed(), llvm::MCRegisterInfo::DiffListIterator::isValid(), llvm_unreachable, MI, MRI, TRI, and llvm::MachineFunction::verify().

Referenced by forward(), INITIALIZE_PASS(), llvm::Mips16InstrInfo::loadImmediate(), and llvm::PPCFrameLowering::replaceFPWithRealFP().

◆ 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 88 of file RegisterScavenging.h.

References llvm::MachineBasicBlock::begin(), forward(), I, and unprocess().

◆ getCurrentPosition()

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

inline

Definition at line 120 of file RegisterScavenging.h.

References FindUnusedReg(), getRegsAvailable(), isRegUsed(), and Reg.

◆ getRegsAvailable()

BitVector RegScavenger::getRegsAvailable ( const TargetRegisterClass * RC )

Return all available registers in the register class in Mask.

Definition at line 299 of file RegisterScavenging.cpp.

References assert(), llvm::BitVector::clearBitsNotInMask(), llvm::BitVector::find_first(), llvm::MachineBasicBlock::getFirstTerminator(), InstrLimit, isRegUsed(), llvm::MCRegAliasIterator::isValid(), llvm::TargetRegisterInfo::isVirtualRegister(), llvm::BitmaskEnumDetail::Mask(), MI, llvm::BitVector::none(), llvm::BitVector::reset(), llvm::BitVector::test(), TRI, and UseMI.

Referenced by getCurrentPosition(), llvm::Mips16InstrInfo::loadImmediate(), llvm::PPCFrameLowering::replaceFPWithRealFP(), and scavengeRegister().

◆ getScavengingFrameIndices()

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

inline

Get an array of scavenging frame indices.

Definition at line 148 of file RegisterScavenging.h.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::SmallVectorTemplateCommon< T, typename >::end(), I, llvm::ARM_PROC::IE, llvm::SmallVectorTemplateBase< T, bool >::push_back(), and scavengeRegister().

◆ isRegUsed()

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

Return if a specific register is currently used.

Definition at line 282 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::available().

Referenced by FindUnusedReg(), forward(), getCurrentPosition(), getRegsAvailable(), llvm::PPCFrameLowering::replaceFPWithRealFP(), llvm::SIRegisterInfo::restoreSGPR(), scavengeRegister(), and llvm::SIRegisterInfo::spillSGPR().

◆ isScavengingFrameIndex()

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

inline

Query whether a frame index is a scavenging frame index.

Definition at line 138 of file RegisterScavenging.h.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::SmallVectorTemplateCommon< T, typename >::end(), I, and llvm::ARM_PROC::IE.

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

◆ scavengeRegister() [1/2]

unsigned RegScavenger::scavengeRegister	(	const TargetRegisterClass *	RC,
		MachineBasicBlock::iterator	I,
		int	SPAdj
	)

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!

Definition at line 535 of file RegisterScavenging.cpp.

References llvm::BitVector::any(), llvm::dbgs(), llvm::MachineInstr::getMF(), getRegsAvailable(), I, isRegUsed(), llvm::MCRegAliasIterator::isValid(), llvm::TargetRegisterInfo::isVirtualRegister(), LLVM_DEBUG, MI, llvm::MachineInstr::operands(), llvm::printReg(), llvm::BitVector::reset(), TRI, and UseMI.

Referenced by llvm::SIInstrInfo::calculateLDSSpillAddress(), llvm::LanaiRegisterInfo::eliminateFrameIndex(), getScavengingFrameIndices(), InsertFPConstInst(), InsertSPConstInst(), ReplaceFrameIndex(), and scavengeRegister().

◆ scavengeRegister() [2/2]

unsigned llvm::RegScavenger::scavengeRegister	(	const TargetRegisterClass *	RegClass,
		int	SPAdj
	)

inline

Definition at line 163 of file RegisterScavenging.h.

References llvm::LiveRegUnits::addUnits(), llvm::LaneBitmask::getAll(), InstrLimit, llvm::MachineRegisterInfo::isReserved(), llvm::LiveRegUnits::removeUnits(), llvm::scavengeFrameVirtualRegs(), scavengeRegister(), scavengeRegisterBackwards(), setRegUsed(), and UseMI.

◆ scavengeRegisterBackwards()

unsigned RegScavenger::scavengeRegisterBackwards	(	const TargetRegisterClass &	RC,
		MachineBasicBlock::iterator	To,
		bool	RestoreAfter,
		int	SPAdj
	)

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.

Definition at line 577 of file RegisterScavenging.cpp.

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

Referenced by llvm::RISCVInstrInfo::insertIndirectBranch(), llvm::SIInstrInfo::insertIndirectBranch(), scavengeRegister(), and scavengeVReg().

◆ setRegUsed()

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

Tell the scavenger a register is used.

Definition at line 53 of file RegisterScavenging.cpp.

References llvm::LiveRegUnits::addRegMasked(), assert(), llvm::TargetSubtargetInfo::getInstrInfo(), llvm::MachineBasicBlock::getParent(), llvm::MachineFunction::getRegInfo(), llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::MachineFunction::getSubtarget(), llvm::LiveRegUnits::init(), MRI, llvm::BitVector::resize(), SI, TII, and TRI.

Referenced by InsertFPConstInst(), llvm::RISCVInstrInfo::insertIndirectBranch(), llvm::SIInstrInfo::insertIndirectBranch(), InsertSPConstInst(), ReplaceFrameIndex(), scavengeFrameVirtualRegsInBlock(), and scavengeRegister().

◆ skipTo()

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

inline

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

Definition at line 114 of file RegisterScavenging.h.

References I.

◆ unprocess() [1/2]

void RegScavenger::unprocess ( )

Invert the behavior of forward() on the current instruction (undo the changes to the available registers made by forward()).

Definition at line 157 of file RegisterScavenging.cpp.

References assert(), llvm::MachineBasicBlock::begin(), llvm::MachineInstr::isDebugInstr(), and MI.

Referenced by forward(), and unprocess().

◆ unprocess() [2/2]

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

inline

Unprocess instructions until you reach the provided iterator.

Definition at line 98 of file RegisterScavenging.h.

References backward(), and unprocess().

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()

◆ 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()

◆ unprocess() [1/2]

◆ unprocess() [2/2]