class MLocTracker

Declaration

class MLocTracker { /* full declaration omitted */ };

Description

Tracker for what values are in machine locations. Listens to the Things being Done by various instructions, and maintains a table of what machine locations have what values (as defined by a ValueIDNum). There are potentially a much larger number of machine locations on the target machine than the actual working-set size of the function. On x86 for example, we're extremely unlikely to want to track values through control or debug registers. To avoid doing so, MLocTracker has several layers of indirection going on, described below, to avoid unnecessarily tracking any location. Here's a sort of diagram of the indexes, read from the bottom up: Size on stack Offset on stack \ / Stack Idx (Where in slot is this?) / / Slot Num (%stack.0) / FrameIdx => SpillNum / \ / SpillID (int) Register number (int) \ / LocationID => LocIdx | LocIdx => ValueIDNum The aim here is that the LocIdx => ValueIDNum vector is just an array of values in numbered locations, so that later analyses can ignore whether the location is a register or otherwise. To map a register / spill location to a LocIdx, you have to use the (sparse) LocationID => LocIdx map. And to build a LocationID for a stack slot, you need to combine identifiers for which stack slot it is and where within that slot is being described. Register mask operands cause trouble by technically defining every register; various hacks are used to avoid tracking registers that are never read and only written by regmasks.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:346

Member Variables

public llvm::MachineFunction& MF

public const llvm::TargetInstrInfo& TII

public const llvm::TargetRegisterInfo& TRI

public const llvm::TargetLowering& TLI

public LiveDebugValues::MLocTracker::LocToValueType LocIdxToIDNum

Map of LocIdxes to the ValueIDNums that they store. This is tightly packed, entries only exist for locations that are being tracked.

public std::vector<LocIdx> LocIDToLocIdx

"Map" of machine location IDs (i.e., raw register or spill number) to the LocIdx key / number for that location. There are always at least as many as the number of registers on the target -- if the value in the register is not being tracked, then the LocIdx value will be zero. New entries are appended if a new spill slot begins being tracked. This, and the corresponding reverse map persist for the analysis of the whole function, and is necessarying for decoding various vectors of values.

public IndexedMap<unsigned int, LiveDebugValues::LocIdxToIndexFunctor> LocIdxToLocID

Inverse map of LocIDToLocIdx.

public SmallSet<llvm::Register, 8> SPAliases

When clobbering register masks, we chose to not believe the machine model and don't clobber SP. Do the same for SP aliases, and for efficiency, keep a set of them here.

public UniqueVector<LiveDebugValues::SpillLoc> SpillLocs

Unique-ification of spill. Used to number them -- their LocID number is the index in SpillLocs minus one plus NumRegs.

public unsigned int CurBB

public unsigned int NumRegs

Cached local copy of the number of registers the target has.

public unsigned int NumSlotIdxes

Number of slot indexes the target has -- distinct segments of a stack slot that can take on the value of a subregister, when a super-register is written to the stack.

public SmallVector<std::pair<const MachineOperand*, unsigned int>, 32> Masks

Collection of register mask operands that have been observed. Second part of pair indicates the instruction that they happened in. Used to reconstruct where defs happened if we start tracking a location later on.

public DenseMap< LiveDebugValues::MLocTracker::StackSlotPos, unsigned int> StackSlotIdxes

Map from a size/offset pair describing a position in a stack slot, to a numeric identifier for that position. Allows easier identification of individual positions.

public DenseMap< unsigned int, LiveDebugValues::MLocTracker::StackSlotPos> StackIdxesToPos

Inverse of StackSlotIdxes.

Method Overview

• public std::string IDAsString(const LiveDebugValues::ValueIDNum & Num) const
• public std::string LocIdxToName(LiveDebugValues::LocIdx Idx) const
• public MLocTracker(llvm::MachineFunction & MF, const llvm::TargetInstrInfo & TII, const llvm::TargetRegisterInfo & TRI, const llvm::TargetLowering & TLI)
• public LiveDebugValues::MLocTracker::MLocIterator begin()
• public void clear()
• public void defReg(llvm::Register R, unsigned int BB, unsigned int Inst)
• public void dump()
• public void dump_mloc_map()
• public llvm::MachineInstrBuilder emitLoc(Optional<LiveDebugValues::LocIdx> MLoc, const llvm::DebugVariable & Var, const LiveDebugValues::DbgValueProperties & Properties)
• public LiveDebugValues::MLocTracker::MLocIterator end()
• public unsigned int getLocID(llvm::Register Reg)
• public unsigned int getLocID(LiveDebugValues::SpillLocationNo Spill, unsigned int SpillSubReg)
• public unsigned int getLocID(LiveDebugValues::SpillLocationNo Spill, LiveDebugValues::MLocTracker::StackSlotPos Idx)
• public unsigned int getLocSizeInBits(LiveDebugValues::LocIdx L) const
• public unsigned int getNumLocs() const
• public Optional<LiveDebugValues::SpillLocationNo> getOrTrackSpillLoc(LiveDebugValues::SpillLoc L)
• public LiveDebugValues::LocIdx getRegMLoc(llvm::Register R)
• public unsigned int getSpillIDWithIdx(LiveDebugValues::SpillLocationNo Spill, unsigned int Idx)
• public LiveDebugValues::LocIdx getSpillMLoc(unsigned int SpillID)
• public bool isRegisterTracked(llvm::Register R)
• public bool isSpill(LiveDebugValues::LocIdx Idx) const
• public void loadFromArray(LiveDebugValues::ValueTable & Locs, unsigned int NewCurBB)
• public LiveDebugValues::SpillLocationNo locIDToSpill(unsigned int ID) const
• public LiveDebugValues::MLocTracker::StackSlotPos locIDToSpillIdx(unsigned int ID) const
• public iterator_range<LiveDebugValues::MLocTracker::MLocIterator> locations()
• public LiveDebugValues::LocIdx lookupOrTrackRegister(unsigned int ID)
• public LiveDebugValues::ValueIDNum readMLoc(LiveDebugValues::LocIdx L)
• public LiveDebugValues::ValueIDNum readReg(llvm::Register R)
• public void reset()
• public void setMLoc(LiveDebugValues::LocIdx L, LiveDebugValues::ValueIDNum Num)
• public void setMPhis(unsigned int NewCurBB)
• public void setReg(llvm::Register R, LiveDebugValues::ValueIDNum ValueID)
• public LiveDebugValues::LocIdx trackRegister(unsigned int ID)
• public void wipeRegister(llvm::Register R)
• public void writeRegMask(const llvm::MachineOperand * MO, unsigned int CurBB, unsigned int InstID)

Methods

¶std::string IDAsString(
    const LiveDebugValues::ValueIDNum& Num) const

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:662

Parameters

const LiveDebugValues::ValueIDNum& Num

¶std::string LocIdxToName(
    LiveDebugValues::LocIdx Idx) const

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:660

Parameters

LiveDebugValues::LocIdx Idx

¶MLocTracker(llvm::MachineFunction& MF,
            const llvm::TargetInstrInfo& TII,
            const llvm::TargetRegisterInfo& TRI,
            const llvm::TargetLowering& TLI)

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:445

Parameters

llvm::MachineFunction& MF

const llvm::TargetInstrInfo& TII

const llvm::TargetRegisterInfo& TRI

const llvm::TargetLowering& TLI

¶LiveDebugValues::MLocTracker::MLocIterator begin()

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:649

¶void clear()

Description

Clear all data. Destroys the LocID < => LocIdx map, which makes most of the information in this pass uninterpretable.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:532

¶void defReg(llvm::Register R,
            unsigned int BB,
            unsigned int Inst)

Description

Record a definition of the specified register at the given block / inst. This doesn't take a ValueIDNum, because the definition and its location are synonymous.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:578

Parameters

llvm::Register R

unsigned int BB

unsigned int Inst

¶void dump()

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:665

¶void dump_mloc_map()

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:667

¶llvm::MachineInstrBuilder emitLoc(
    Optional<LiveDebugValues::LocIdx> MLoc,
    const llvm::DebugVariable& Var,
    const LiveDebugValues::DbgValueProperties&
        Properties)

Description

Create a DBG_VALUE based on machine location \p MLoc. Qualify it with the information in \pProperties, for variable Var. Don't insert it anywhere, just return the builder for it.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:673

Parameters

Optional<LiveDebugValues::LocIdx> MLoc

const llvm::DebugVariable& Var

const LiveDebugValues::DbgValueProperties& Properties

¶LiveDebugValues::MLocTracker::MLocIterator end()

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:651

¶unsigned int getLocID(llvm::Register Reg)

Description

Produce location ID number for a Register. Provides some small amount of type safety.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:451

Parameters

llvm::Register Reg

The register we're looking up.

¶unsigned int getLocID(
    LiveDebugValues::SpillLocationNo Spill,
    unsigned int SpillSubReg)

Description

Produce location ID number for a spill position.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:456

Parameters

LiveDebugValues::SpillLocationNo Spill

The number of the spill we're fetching the location for.

unsigned int SpillSubReg

Subregister within the spill we're addressing.

¶unsigned int getLocID(
    LiveDebugValues::SpillLocationNo Spill,
    LiveDebugValues::MLocTracker::StackSlotPos
        Idx)

Description

Produce location ID number for a spill position.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:465

Parameters

LiveDebugValues::SpillLocationNo Spill

The number of the spill we're fetching the location for.\apramSpillIdx size/offset within the spill slot to be addressed.

LiveDebugValues::MLocTracker::StackSlotPos Idx

¶unsigned int getLocSizeInBits(
    LiveDebugValues::LocIdx L) const

Description

How large is this location (aka, how wide is a value defined there?).

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:637

Parameters

LiveDebugValues::LocIdx L

¶unsigned int getNumLocs() const

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:501

¶Optional<LiveDebugValues::SpillLocationNo>
getOrTrackSpillLoc(LiveDebugValues::SpillLoc L)

Description

Find LocIdx for SpillLoc \p L, creating a new one if it's not tracked. Returns None when in scenarios where a spill slot could be tracked, but we would likely run into resource limitations.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:625

Parameters

LiveDebugValues::SpillLoc L

¶LiveDebugValues::LocIdx getRegMLoc(
    llvm::Register R)

Description

Determine the LocIdx of an existing register.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:610

Parameters

llvm::Register R

¶unsigned int getSpillIDWithIdx(
    LiveDebugValues::SpillLocationNo Spill,
    unsigned int Idx)

Description

Given a spill number, and a slot within the spill, calculate the ID number for that location.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:476

Parameters

LiveDebugValues::SpillLocationNo Spill

unsigned int Idx

¶LiveDebugValues::LocIdx getSpillMLoc(
    unsigned int SpillID)

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:628

Parameters

unsigned int SpillID

¶bool isRegisterTracked(llvm::Register R)

Description

Is register R currently tracked by MLocTracker?

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:570

Parameters

llvm::Register R

¶bool isSpill(LiveDebugValues::LocIdx Idx) const

Description

Return true if Idx is a spill machine location.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:634

Parameters

LiveDebugValues::LocIdx Idx

¶void loadFromArray(
    LiveDebugValues::ValueTable& Locs,
    unsigned int NewCurBB)

Description

Load values for each location from array of ValueIDNums. Take current bbnum just in case we read a value from a hitherto untouched register.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:514

Parameters

LiveDebugValues::ValueTable& Locs

unsigned int NewCurBB

¶LiveDebugValues::SpillLocationNo locIDToSpill(
    unsigned int ID) const

Description

Return the spill number that a location ID corresponds to.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:485

Parameters

unsigned int ID

¶LiveDebugValues::MLocTracker::StackSlotPos
locIDToSpillIdx(unsigned int ID) const

Description

Returns the spill-slot size/offs that a location ID corresponds to.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:494

Parameters

unsigned int ID

¶iterator_range<
    LiveDebugValues::MLocTracker::MLocIterator>
locations()

Description

Return a range over all locations currently tracked.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:656

¶LiveDebugValues::LocIdx lookupOrTrackRegister(
    unsigned int ID)

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:562

Parameters

unsigned int ID

¶LiveDebugValues::ValueIDNum readMLoc(
    LiveDebugValues::LocIdx L)

Description

Read the value of a particular location

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:553

Parameters

LiveDebugValues::LocIdx L

¶LiveDebugValues::ValueIDNum readReg(
    llvm::Register R)

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:593

Parameters

llvm::Register R

¶void reset()

Description

Wipe any un-necessary location records after traversing a block.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:523

¶void setMLoc(LiveDebugValues::LocIdx L,
             LiveDebugValues::ValueIDNum Num)

Description

Set a locaiton to a certain value.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:547

Parameters

LiveDebugValues::LocIdx L

LiveDebugValues::ValueIDNum Num

¶void setMPhis(unsigned int NewCurBB)

Description

Reset all locations to contain a PHI value at the designated block. Used sometimes for actual PHI values, othertimes to indicate the block entry value (before any more information is known).

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:506

Parameters

unsigned int NewCurBB

¶void setReg(llvm::Register R,
            LiveDebugValues::ValueIDNum ValueID)

Description

Set a register to a value number. To be used if the value number is known in advance.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:587

Parameters

llvm::Register R

LiveDebugValues::ValueIDNum ValueID

¶LiveDebugValues::LocIdx trackRegister(
    unsigned int ID)

Description

Create a LocIdx for an untracked register ID. Initialize it to either an mphi value representing a live-in, or a recent register mask clobber.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:560

Parameters

unsigned int ID

¶void wipeRegister(llvm::Register R)

Description

Reset a register value to zero / empty. Needed to replicate the VarLoc implementation where a copy to/from a register effectively clears the contents of the source register. (Values can only have one machine location in VarLocBasedImpl).

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:603

Parameters

llvm::Register R

¶void writeRegMask(const llvm::MachineOperand* MO,
                  unsigned int CurBB,
                  unsigned int InstID)

Description

Record a RegMask operand being executed. Defs any register we currently track, stores a pointer to the mask in case we have to account for it later.

Declared at: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.h:620

Parameters

const llvm::MachineOperand* MO

unsigned int CurBB

unsigned int InstID