RABasic provides a minimal implementation of the basic register allocation algorithm. More...

#include "CodeGen/RegAllocBasic.h"

Inheritance diagram for llvm::RABasic:

Public Member Functions
	RABasic (const RegAllocFilterFunc F=nullptr)
StringRef	getPassName () const override
	Return the pass name.
void	getAnalysisUsage (AnalysisUsage &AU) const override
	RABasic analysis usage.
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.
Spiller &	spiller () override
void	enqueueImpl (const LiveInterval *LI) override
	enqueue - Add VirtReg to the priority queue of unassigned registers.
const LiveInterval *	dequeue () override
	dequeue - Return the next unassigned register, or NULL.
MCRegister	selectOrSplit (const LiveInterval &VirtReg, SmallVectorImpl< Register > &SplitVRegs) override
bool	runOnMachineFunction (MachineFunction &mf) override
	Perform register allocation.
MachineFunctionProperties	getRequiredProperties () const override
MachineFunctionProperties	getClearedProperties () const override
bool	spillInterferences (const LiveInterval &VirtReg, MCRegister PhysReg, SmallVectorImpl< Register > &SplitVRegs)
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
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
Static Public Attributes inherited from llvm::RegAllocBase
static bool	VerifyEnabled = false
	VerifyEnabled - True when -verify-regalloc is given.

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
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.
Protected Member Functions inherited from llvm::RegAllocBase
	RegAllocBase (const RegAllocFilterFunc F=nullptr)
virtual	~RegAllocBase ()=default
void	init (VirtRegMap &vrm, LiveIntervals &lis, LiveRegMatrix &mat)
bool	shouldAllocateRegister (Register Reg)
	Get whether a given register should be allocated.
void	allocatePhysRegs ()
virtual void	postOptimization ()
void	cleanupFailedVReg (Register FailedVReg, MCRegister PhysReg, SmallVectorImpl< Register > &SplitRegs)
	Perform cleanups on registers that failed to allocate.
void	enqueue (const LiveInterval *LI)
	enqueue - Add VirtReg to the priority queue of unassigned registers.
MCPhysReg	getErrorAssignment (const TargetRegisterClass &RC, const MachineInstr *CtxMI=nullptr)
	Query a physical register to use as a filler in contexts where the allocation has failed.
virtual void	aboutToRemoveInterval (const LiveInterval &LI)
	Method called when the allocator is about to remove a LiveInterval.
Protected Attributes inherited from llvm::RegAllocBase
const TargetRegisterInfo *	TRI = nullptr
MachineRegisterInfo *	MRI = nullptr
VirtRegMap *	VRM = nullptr
LiveIntervals *	LIS = nullptr
LiveRegMatrix *	Matrix = nullptr
RegisterClassInfo	RegClassInfo
SmallPtrSet< MachineInstr *, 32 >	DeadRemats
	Inst which is a def of an original reg and whose defs are already all dead after remat is saved in DeadRemats.
SmallSet< Register, 2 >	FailedVRegs
Static Protected Attributes inherited from llvm::RegAllocBase
static const char	TimerGroupName [] = "regalloc"
static const char	TimerGroupDescription [] = "Register Allocation"

Detailed Description

RABasic provides a minimal implementation of the basic register allocation algorithm.

It prioritizes live virtual registers by spill weight and spills whenever a register is unavailable. This is not practical in production but provides a useful baseline both for measuring other allocators and comparing the speed of the basic algorithm against other styles of allocators.

Definition at line 37 of file RegAllocBasic.h.

Constructor & Destructor Documentation

◆ RABasic()

RABasic::RABasic ( const RegAllocFilterFunc F = nullptr )

Definition at line 87 of file RegAllocBasic.cpp.

References F, ID, llvm::MachineFunctionPass::MachineFunctionPass(), and llvm::RegAllocBase::RegAllocBase().

Member Function Documentation

◆ dequeue()

const LiveInterval * llvm::RABasic::dequeue ( )

inlineoverridevirtual

dequeue - Return the next unassigned register, or NULL.

Implements llvm::RegAllocBase.

Definition at line 71 of file RegAllocBasic.h.

◆ enqueueImpl()

void llvm::RABasic::enqueueImpl ( const LiveInterval * LI )

inlineoverridevirtual

enqueue - Add VirtReg to the priority queue of unassigned registers.

Implements llvm::RegAllocBase.

Definition at line 69 of file RegAllocBasic.h.

◆ getAnalysisUsage()

void RABasic::getAnalysisUsage ( AnalysisUsage & AU ) const

overridevirtual

RABasic analysis usage.

Reimplemented from llvm::MachineFunctionPass.

Definition at line 90 of file RegAllocBasic.cpp.

References llvm::AnalysisUsage::addPreserved(), llvm::AnalysisUsage::addPreservedID(), llvm::AnalysisUsage::addRequired(), llvm::AnalysisUsage::addRequiredID(), llvm::MachineFunctionPass::getAnalysisUsage(), llvm::MachineDominatorsID, and llvm::AnalysisUsage::setPreservesCFG().

◆ getClearedProperties()

MachineFunctionProperties llvm::RABasic::getClearedProperties ( ) const

inlineoverridevirtual

Reimplemented from llvm::MachineFunctionPass.

Definition at line 90 of file RegAllocBasic.h.

References llvm::MachineFunctionProperties::IsSSA, and llvm::MachineFunctionProperties::set().

◆ getPassName()

StringRef llvm::RABasic::getPassName ( ) const

inlineoverridevirtual

Return the pass name.

Reimplemented from llvm::Pass.

Definition at line 60 of file RegAllocBasic.h.

◆ getRequiredProperties()

MachineFunctionProperties llvm::RABasic::getRequiredProperties ( ) const

inlineoverridevirtual

Reimplemented from llvm::MachineFunctionPass.

Definition at line 85 of file RegAllocBasic.h.

References llvm::MachineFunctionProperties::NoPHIs, and llvm::MachineFunctionProperties::set().

◆ releaseMemory()

void RABasic::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 116 of file RegAllocBasic.cpp.

Referenced by runOnMachineFunction().