class LiveVariables

Declaration

class LiveVariables : public MachineFunctionPass { /* full declaration omitted */ };

Description

MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of passes that operate on the MachineFunction representation. Instead of overriding runOnFunction, subclasses override runOnMachineFunction.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:47

Inherits from: MachineFunctionPass

Member Variables

private IndexedMap<llvm::LiveVariables::VarInfo, llvm::VirtReg2IndexFunctor> VirtRegInfo

VirtRegInfo - This list is a mapping from virtual register number to variable information.

private SparseBitVector<> PHIJoins

PHIJoins - list of virtual registers that are PHI joins. These registers may have multiple definitions, and they require special handling when building live intervals.

private llvm::MachineFunction* MF

private llvm::MachineRegisterInfo* MRI

private const llvm::TargetRegisterInfo* TRI

private std::vector<MachineInstr*> PhysRegDef

private std::vector<MachineInstr*> PhysRegUse

private std::vector<SmallVector<unsigned int, 4>> PHIVarInfo

private DenseMap<llvm::MachineInstr*, unsigned int> DistanceMap

public static char ID

Method Overview

• private llvm::MachineInstr * FindLastPartialDef(llvm::Register Reg, SmallSet<unsigned int, 4> & PartDefRegs)
• private llvm::MachineInstr * FindLastRefOrPartRef(llvm::Register Reg)
• private void HandlePhysRegDef(llvm::Register Reg, llvm::MachineInstr * MI, SmallVectorImpl<unsigned int> & Defs)
• private bool HandlePhysRegKill(llvm::Register Reg, llvm::MachineInstr * MI)
• private void HandlePhysRegUse(llvm::Register Reg, llvm::MachineInstr & MI)
• private void HandleRegMask(const llvm::MachineOperand &)
• public void HandleVirtRegDef(llvm::Register reg, llvm::MachineInstr & MI)
• public void HandleVirtRegUse(llvm::Register reg, llvm::MachineBasicBlock * MBB, llvm::MachineInstr & MI)
• public LiveVariables()
• public void MarkVirtRegAliveInBlock(llvm::LiveVariables::VarInfo & VRInfo, llvm::MachineBasicBlock * DefBlock, llvm::MachineBasicBlock * BB, SmallVectorImpl<llvm::MachineBasicBlock *> & WorkList)
• public void MarkVirtRegAliveInBlock(llvm::LiveVariables::VarInfo & VRInfo, llvm::MachineBasicBlock * DefBlock, llvm::MachineBasicBlock * BB)
• public bool RegisterDefIsDead(llvm::MachineInstr & MI, llvm::Register Reg) const
• private void UpdatePhysRegDefs(llvm::MachineInstr & MI, SmallVectorImpl<unsigned int> & Defs)
• public void addNewBlock(llvm::MachineBasicBlock * BB, llvm::MachineBasicBlock * DomBB, llvm::MachineBasicBlock * SuccBB, std::vector<SparseBitVector<>> & LiveInSets)
• public void addNewBlock(llvm::MachineBasicBlock * BB, llvm::MachineBasicBlock * DomBB, llvm::MachineBasicBlock * SuccBB)
• public void addVirtualRegisterDead(llvm::Register IncomingReg, llvm::MachineInstr & MI, bool AddIfNotFound = false)
• public void addVirtualRegisterKilled(llvm::Register IncomingReg, llvm::MachineInstr & MI, bool AddIfNotFound = false)
• private void analyzePHINodes(const llvm::MachineFunction & Fn)
• public void getAnalysisUsage(llvm::AnalysisUsage & AU) const
• public llvm::LiveVariables::VarInfo & getVarInfo(llvm::Register Reg)
• public bool isLiveIn(llvm::Register Reg, const llvm::MachineBasicBlock & MBB)
• public bool isLiveOut(llvm::Register Reg, const llvm::MachineBasicBlock & MBB)
• public bool isPHIJoin(llvm::Register Reg)
• public void recomputeForSingleDefVirtReg(llvm::Register Reg)
• public void releaseMemory()
• public bool removeVirtualRegisterDead(llvm::Register Reg, llvm::MachineInstr & MI)
• public bool removeVirtualRegisterKilled(llvm::Register Reg, llvm::MachineInstr & MI)
• public void removeVirtualRegistersKilled(llvm::MachineInstr & MI)
• public void replaceKillInstruction(llvm::Register Reg, llvm::MachineInstr & OldMI, llvm::MachineInstr & NewMI)
• private void runOnBlock(llvm::MachineBasicBlock * MBB, unsigned int NumRegs)
• private void runOnInstr(llvm::MachineInstr & MI, SmallVectorImpl<unsigned int> & Defs)
• public bool runOnMachineFunction(llvm::MachineFunction & MF)
• public void setPHIJoin(llvm::Register Reg)

Inherited from MachineFunctionPass:

• public doInitialization
• protected getAnalysisUsage
• protected getClearedProperties
• protected getRequiredProperties
• protected getSetProperties
• protected runOnMachineFunction

Inherited from FunctionPass:

• public assignPassManager
• public createPrinterPass
• public getPotentialPassManagerType
• public runOnFunction
• protected skipFunction

Inherited from Pass:

• public assignPassManager
• public createPass
• public createPrinterPass
• public doFinalization
• public doInitialization
• public dump
• public dumpPassStructure
• public getAdjustedAnalysisPointer
• public getAnalysis
• public getAnalysis
• public getAnalysisID
• public getAnalysisID
• public getAnalysisIfAvailable
• public getAnalysisUsage
• public getAsImmutablePass
• public getAsPMDataManager
• public getPassID
• public getPassKind
• public getPassName
• public getPotentialPassManagerType
• public getResolver
• public lookupPassInfo
• public lookupPassInfo
• public mustPreserveAnalysisID
• public preparePassManager
• public print
• public releaseMemory
• public setResolver
• public verifyAnalysis

Methods

¶llvm::MachineInstr* FindLastPartialDef(
    llvm::Register Reg,
    SmallSet<unsigned int, 4>& PartDefRegs)

Description

FindLastPartialDef - Return the last partial def of the specified register. Also returns the sub-registers that're defined by the instruction.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:169

Parameters

llvm::Register Reg

SmallSet<unsigned int, 4>& PartDefRegs

¶llvm::MachineInstr* FindLastRefOrPartRef(
    llvm::Register Reg)

Description

FindLastRefOrPartRef - Return the last reference or partial reference of the specified register.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:164

Parameters

llvm::Register Reg

¶void HandlePhysRegDef(
    llvm::Register Reg,
    llvm::MachineInstr* MI,
    SmallVectorImpl<unsigned int>& Defs)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:158

Parameters

llvm::Register Reg

llvm::MachineInstr* MI

SmallVectorImpl<unsigned int>& Defs

¶bool HandlePhysRegKill(llvm::Register Reg,
                       llvm::MachineInstr* MI)

Description

HandlePhysRegKill - Add kills of Reg and its sub-registers to the uses. Pay special attention to the sub-register uses which may come below the last use of the whole register.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:152

Parameters

llvm::Register Reg

llvm::MachineInstr* MI

¶void HandlePhysRegUse(llvm::Register Reg,
                      llvm::MachineInstr& MI)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:157

Parameters

llvm::Register Reg

llvm::MachineInstr& MI

¶void HandleRegMask(const llvm::MachineOperand&)

Description

HandleRegMask - Call HandlePhysRegKill for all registers clobbered by Mask.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:155

Parameters

const llvm::MachineOperand&

¶void HandleVirtRegDef(llvm::Register reg,
                      llvm::MachineInstr& MI)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:285

Parameters

llvm::Register reg

llvm::MachineInstr& MI

¶void HandleVirtRegUse(
    llvm::Register reg,
    llvm::MachineBasicBlock* MBB,
    llvm::MachineInstr& MI)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:286

Parameters

llvm::Register reg

llvm::MachineBasicBlock* MBB

llvm::MachineInstr& MI

¶LiveVariables()

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:50

¶void MarkVirtRegAliveInBlock(
    llvm::LiveVariables::VarInfo& VRInfo,
    llvm::MachineBasicBlock* DefBlock,
    llvm::MachineBasicBlock* BB,
    SmallVectorImpl<llvm::MachineBasicBlock*>&
        WorkList)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:281

Parameters

llvm::LiveVariables::VarInfo& VRInfo

llvm::MachineBasicBlock* DefBlock

llvm::MachineBasicBlock* BB

SmallVectorImpl<llvm::MachineBasicBlock*>& WorkList

¶void MarkVirtRegAliveInBlock(
    llvm::LiveVariables::VarInfo& VRInfo,
    llvm::MachineBasicBlock* DefBlock,
    llvm::MachineBasicBlock* BB)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:279

Parameters

llvm::LiveVariables::VarInfo& VRInfo

llvm::MachineBasicBlock* DefBlock

llvm::MachineBasicBlock* BB

¶bool RegisterDefIsDead(llvm::MachineInstr& MI,
                       llvm::Register Reg) const

Description

RegisterDefIsDead - Return true if the specified instruction defines the specified register, but that definition is dead.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:187

Parameters

llvm::MachineInstr& MI

llvm::Register Reg

¶void UpdatePhysRegDefs(
    llvm::MachineInstr& MI,
    SmallVectorImpl<unsigned int>& Defs)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:160

Parameters

llvm::MachineInstr& MI

SmallVectorImpl<unsigned int>& Defs

¶void addNewBlock(
    llvm::MachineBasicBlock* BB,
    llvm::MachineBasicBlock* DomBB,
    llvm::MachineBasicBlock* SuccBB,
    std::vector<SparseBitVector<>>& LiveInSets)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:305

Parameters

llvm::MachineBasicBlock* BB

llvm::MachineBasicBlock* DomBB

llvm::MachineBasicBlock* SuccBB

std::vector<SparseBitVector<>>& LiveInSets

¶void addNewBlock(llvm::MachineBasicBlock* BB,
                 llvm::MachineBasicBlock* DomBB,
                 llvm::MachineBasicBlock* SuccBB)

Description

addNewBlock - Add a new basic block BB between DomBB and SuccBB. All variables that are live out of DomBB and live into SuccBB will be marked as passing live through BB. This method assumes that the machine code is still in SSA form.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:301

Parameters

llvm::MachineBasicBlock* BB

llvm::MachineBasicBlock* DomBB

llvm::MachineBasicBlock* SuccBB

¶void addVirtualRegisterDead(
    llvm::Register IncomingReg,
    llvm::MachineInstr& MI,
    bool AddIfNotFound = false)

Description

addVirtualRegisterDead - Add information about the fact that the specified register is dead after being used by the specified instruction. If AddIfNotFound is true, add a implicit operand if it's not found.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:242

Parameters

llvm::Register IncomingReg

llvm::MachineInstr& MI

bool AddIfNotFound = false

¶void addVirtualRegisterKilled(
    llvm::Register IncomingReg,
    llvm::MachineInstr& MI,
    bool AddIfNotFound = false)

Description

addVirtualRegisterKilled - Add information about the fact that the specified register is killed after being used by the specified instruction. If AddIfNotFound is true, add a implicit operand if it's not found.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:207

Parameters

llvm::Register IncomingReg

llvm::MachineInstr& MI

bool AddIfNotFound = false

¶void analyzePHINodes(
    const llvm::MachineFunction& Fn)

Description

analyzePHINodes - Gather information about the PHI nodes in here. In particular, we want to map the variable information of a virtual register which is used in a PHI node. We map that to the BB the vreg is coming from.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:176

Parameters

const llvm::MachineFunction& Fn

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

Description

getAnalysisUsage - Subclasses that override getAnalysisUsage must call this. For MachineFunctionPasses, calling AU.preservesCFG() indicates that the pass does not modify the MachineBasicBlock CFG.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:269

Parameters

llvm::AnalysisUsage& AU

¶llvm::LiveVariables::VarInfo& getVarInfo(
    llvm::Register Reg)

Description

getVarInfo - Return the VarInfo structure for the specified VIRTUAL register.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:277

Parameters

llvm::Register Reg

¶bool isLiveIn(llvm::Register Reg,
              const llvm::MachineBasicBlock& MBB)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:288

Parameters

llvm::Register Reg

const llvm::MachineBasicBlock& MBB

¶bool isLiveOut(llvm::Register Reg,
               const llvm::MachineBasicBlock& MBB)

Description

isLiveOut - Determine if Reg is live out from MBB, when not considering PHI nodes. This means that Reg is either killed by a successor block or passed through one.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:295

Parameters

llvm::Register Reg

const llvm::MachineBasicBlock& MBB

¶bool isPHIJoin(llvm::Register Reg)

Description

isPHIJoin - Return true if Reg is a phi join register.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:311

Parameters

llvm::Register Reg

¶void recomputeForSingleDefVirtReg(
    llvm::Register Reg)

Description

Recompute liveness from scratch for a virtual register \p Reg that is known to have a single def that dominates all uses. This can be useful after removing some uses of \p Reg. It is not necessary for the whole machine function to be in SSA form.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:196

Parameters

llvm::Register Reg

¶void releaseMemory()

Description

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.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:271

¶bool removeVirtualRegisterDead(
    llvm::Register Reg,
    llvm::MachineInstr& MI)

Description

removeVirtualRegisterDead - Remove the specified kill of the virtual register from the live variable information. Returns true if the variable was marked dead at the specified instruction, false otherwise.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:252

Parameters

llvm::Register Reg

llvm::MachineInstr& MI

¶bool removeVirtualRegisterKilled(
    llvm::Register Reg,
    llvm::MachineInstr& MI)

Description

removeVirtualRegisterKilled - Remove the specified kill of the virtual register from the live variable information. Returns true if the variable was marked as killed by the specified instruction, false otherwise.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:217

Parameters

llvm::Register Reg

llvm::MachineInstr& MI

¶void removeVirtualRegistersKilled(
    llvm::MachineInstr& MI)

Description

removeVirtualRegistersKilled - Remove all killed info for the specified instruction.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:237

Parameters

llvm::MachineInstr& MI

¶void replaceKillInstruction(
    llvm::Register Reg,
    llvm::MachineInstr& OldMI,
    llvm::MachineInstr& NewMI)

Description

replaceKillInstruction - Update register kill info by replacing a kill instruction with a new one.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:200

Parameters

llvm::Register Reg

llvm::MachineInstr& OldMI

llvm::MachineInstr& NewMI

¶void runOnBlock(llvm::MachineBasicBlock* MBB,
                unsigned int NumRegs)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:180

Parameters

llvm::MachineBasicBlock* MBB

unsigned int NumRegs

¶void runOnInstr(
    llvm::MachineInstr& MI,
    SmallVectorImpl<unsigned int>& Defs)

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:178

Parameters

llvm::MachineInstr& MI

SmallVectorImpl<unsigned int>& Defs

¶bool runOnMachineFunction(
    llvm::MachineFunction& MF)

Description

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

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:183

Parameters

llvm::MachineFunction& MF

¶void setPHIJoin(llvm::Register Reg)

Description

setPHIJoin - Mark Reg as a phi join register.

Declared at: llvm/include/llvm/CodeGen/LiveVariables.h:314

Parameters

llvm::Register Reg