Tracker for converting machine value locations and variable values into variable locations (the output of LiveDebugValues), recorded as DBG_VALUEs specifying block live-in locations and transfers within blocks. More...

Collaboration diagram for TransferTracker:

[legend]

Classes
struct	LocAndProperties

struct	Transfer
	Record of all changes in variable locations at a block position. More...

struct	UseBeforeDef
	Record of a use-before-def: created when a value that's live-in to the current block isn't available in any machine location, but it will be defined in this block. More...

Public Member Functions
	TransferTracker (const TargetInstrInfo TII, MLocTracker MTracker, MachineFunction &MF, const TargetRegisterInfo &TRI, const BitVector &CalleeSavedRegs, const TargetPassConfig &TPC)

void	loadInlocs (MachineBasicBlock &MBB, ValueTable &MLocs, const SmallVectorImpl< std::pair< DebugVariable, DbgValue >> &VLocs, unsigned NumLocs)
	Load object with live-in variable values. More...

void	addUseBeforeDef (const DebugVariable &Var, const DbgValueProperties &Properties, ValueIDNum ID)
	Record that `Var` has value `ID`, a value that becomes available later in the function. More...

void	checkInstForNewValues (unsigned Inst, MachineBasicBlock::iterator pos)
	After the instruction at index `Inst` and position `pos` has been processed, check whether it defines a variable value in a use-before-def. More...

void	flushDbgValues (MachineBasicBlock::iterator Pos, MachineBasicBlock *MBB)
	Helper to move created DBG_VALUEs into Transfers collection. More...

bool	isEntryValueVariable (const DebugVariable &Var, const DIExpression *Expr) const

bool	isEntryValueValue (const ValueIDNum &Val) const

bool	recoverAsEntryValue (const DebugVariable &Var, const DbgValueProperties &Prop, const ValueIDNum &Num)

void	redefVar (const MachineInstr &MI)
	Change a variable value after encountering a DBG_VALUE inside a block. More...

void	redefVar (const MachineInstr &MI, const DbgValueProperties &Properties, Optional< LocIdx > OptNewLoc)
	Handle a change in variable location within a block. More...

void	clobberMloc (LocIdx MLoc, MachineBasicBlock::iterator Pos, bool MakeUndef=true)
	Account for a location `mloc` being clobbered. More...

void	transferMlocs (LocIdx Src, LocIdx Dst, MachineBasicBlock::iterator Pos)
	Transfer variables based on `Src` to be based on `Dst`. More...

MachineInstrBuilder	emitMOLoc (const MachineOperand &MO, const DebugVariable &Var, const DbgValueProperties &Properties)

Public Attributes
const TargetInstrInfo *	TII

const TargetLowering *	TLI

MLocTracker *	MTracker
	This machine location tracker is assumed to always contain the up-to-date value mapping for all machine locations. More...

MachineFunction &	MF

bool	ShouldEmitDebugEntryValues

SmallVector< Transfer, 32 >	Transfers
	Collection of transfers (DBG_VALUEs) to be inserted. More...

SmallVector< ValueIDNum, 32 >	VarLocs
	Local cache of what-value-is-in-what-LocIdx. More...

DenseMap< LocIdx, SmallSet< DebugVariable, 4 > >	ActiveMLocs
	Map from LocIdxes to which DebugVariables are based that location. More...

DenseMap< DebugVariable, LocAndProperties >	ActiveVLocs
	Map from DebugVariable to it's current location and qualifying meta information. More...

SmallVector< MachineInstr *, 4 >	PendingDbgValues
	Temporary cache of DBG_VALUEs to be entered into the Transfers collection. More...

DenseMap< unsigned, SmallVector< UseBeforeDef, 1 > >	UseBeforeDefs
	Map from instruction index (within the block) to the set of UseBeforeDefs that become defined at that instruction. More...

DenseSet< DebugVariable >	UseBeforeDefVariables
	The set of variables that are in UseBeforeDefs and can become a location once the relevant value is defined. More...

const TargetRegisterInfo &	TRI

const BitVector &	CalleeSavedRegs

Detailed Description

Tracker for converting machine value locations and variable values into variable locations (the output of LiveDebugValues), recorded as DBG_VALUEs specifying block live-in locations and transfers within blocks.

Operating on a per-block basis, this class takes a (pre-loaded) MLocTracker and must be initialized with the set of variable values that are live-in to the block. The caller then repeatedly calls process(). TransferTracker picks out variable locations for the live-in variable values (if there is a location) and creates the corresponding DBG_VALUEs. Then, as the block is stepped through, transfers of values between machine locations are identified and if profitable, a DBG_VALUE created.

This is where debug use-before-defs would be resolved: a variable with an unavailable value could materialize in the middle of a block, when the value becomes available. Or, we could detect clobbers and re-specify the variable in a backup location. (XXX these are unimplemented).

Definition at line 174 of file InstrRefBasedImpl.cpp.

Constructor & Destructor Documentation

◆ TransferTracker()

TransferTracker::TransferTracker	(	const TargetInstrInfo *	TII,
		MLocTracker *	MTracker,
		MachineFunction &	MF,
		const TargetRegisterInfo &	TRI,
		const BitVector &	CalleeSavedRegs,
		const TargetPassConfig &	TPC
	)

inline

Definition at line 245 of file InstrRefBasedImpl.cpp.

References llvm::MachineFunction::getSubtarget(), llvm::TargetSubtargetInfo::getTargetLowering(), llvm::TargetPassConfig::getTM(), and TM.

Member Function Documentation

◆ addUseBeforeDef()

void TransferTracker::addUseBeforeDef	(	const DebugVariable &	Var,
		const DbgValueProperties &	Properties,
		ValueIDNum	ID
	)

inline

Record that Var has value ID, a value that becomes available later in the function.

Definition at line 354 of file InstrRefBasedImpl.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert().

◆ checkInstForNewValues()

void TransferTracker::checkInstForNewValues	(	unsigned	Inst,
		MachineBasicBlock::iterator	pos
	)

inline

After the instruction at index Inst and position pos has been processed, check whether it defines a variable value in a use-before-def.

If so, and the variable value hasn't changed since the start of the block, create a DBG_VALUE.

Definition at line 365 of file InstrRefBasedImpl.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::count(), LiveDebugValues::MLocTracker::emitLoc(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::end(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::find(), and LiveDebugValues::MLocTracker::readMLoc().

◆ clobberMloc()

void TransferTracker::clobberMloc	(	LocIdx	MLoc,
		MachineBasicBlock::iterator	Pos,
		bool	MakeUndef = `true`
	)

inline

Account for a location mloc being clobbered.

Examine the variable locations that will be terminated: and try to recover them by using another location. Optionally, given MakeUndef, emit a DBG_VALUE to explicitly terminate a location if it can't be recovered.

Definition at line 531 of file InstrRefBasedImpl.cpp.

◆ emitMOLoc()

MachineInstrBuilder TransferTracker::emitMOLoc	(	const MachineOperand &	MO,
		const DebugVariable &	Var,
		const DbgValueProperties &	Properties
	)

inline

Definition at line 633 of file InstrRefBasedImpl.cpp.

References llvm::BuildMI(), LiveDebugValues::DbgValueProperties::DIExpr, DL, llvm::MDNode::get(), llvm::MDNode::getContext(), llvm::DebugVariable::getInlinedAt(), llvm::DILocalVariable::getScope(), llvm::DebugVariable::getVariable(), LiveDebugValues::DbgValueProperties::Indirect, and TII.

◆ flushDbgValues()

void TransferTracker::flushDbgValues	(	MachineBasicBlock::iterator	Pos,
		MachineBasicBlock *	MBB
	)

inline

Helper to move created DBG_VALUEs into Transfers collection.

Definition at line 391 of file InstrRefBasedImpl.cpp.

References llvm::MachineBasicBlock::begin(), llvm::SmallVectorImpl< T >::clear(), llvm::getBundleStart(), llvm::MachineBasicBlock::instr_begin(), and MBB.

◆ isEntryValueValue()

bool TransferTracker::isEntryValueValue ( const ValueIDNum & Val ) const

inline

Definition at line 420 of file InstrRefBasedImpl.cpp.

References FP, LiveDebugValues::ValueIDNum::getBlock(), llvm::TargetRegisterInfo::getFrameRegister(), LiveDebugValues::ValueIDNum::getLoc(), llvm::TargetLoweringBase::getStackPointerRegisterToSaveRestore(), LiveDebugValues::ValueIDNum::isPHI(), LiveDebugValues::MLocTracker::isSpill(), LiveDebugValues::MLocTracker::LocIdxToLocID, and TRI.

◆ isEntryValueVariable()

bool TransferTracker::isEntryValueVariable	(	const DebugVariable &	Var,
		const DIExpression *	Expr
	)		const

inline

Definition at line 406 of file InstrRefBasedImpl.cpp.

References llvm::DebugVariable::getInlinedAt(), llvm::DIExpression::getNumElements(), llvm::DebugVariable::getVariable(), and llvm::DILocalVariable::isParameter().

◆ loadInlocs()

void TransferTracker::loadInlocs	(	MachineBasicBlock &	MBB,
		ValueTable &	MLocs,
		const SmallVectorImpl< std::pair< DebugVariable, DbgValue >> &	VLocs,
		unsigned	NumLocs
	)

inline

Load object with live-in variable values.

mlocs contains the live-in values in each machine location, while vlocs the live-in variable values. This method picks variable locations for the live-in variables, creates DBG_VALUEs and puts them in Transfers, then prepares the other object fields to track variable locations as we step through the block. FIXME: could just examine mloctracker instead of passing in mlocs?

Definition at line 262 of file InstrRefBasedImpl.cpp.

◆ recoverAsEntryValue()

bool TransferTracker::recoverAsEntryValue	(	const DebugVariable &	Var,
		const DbgValueProperties &	Prop,
		const ValueIDNum &	Num
	)

inline

Definition at line 435 of file InstrRefBasedImpl.cpp.

References llvm::MachineOperand::CreateReg(), LiveDebugValues::DbgValueProperties::DIExpr, llvm::DIExpression::EntryValue, LiveDebugValues::ValueIDNum::getLoc(), LiveDebugValues::DbgValueProperties::Indirect, LiveDebugValues::MLocTracker::LocIdxToLocID, and llvm::DIExpression::prepend().

◆ redefVar() [1/2]

void TransferTracker::redefVar ( const MachineInstr & MI )

inline

Change a variable value after encountering a DBG_VALUE inside a block.

Definition at line 462 of file InstrRefBasedImpl.cpp.

References llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::end(), llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::erase(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::erase(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::find(), llvm::MachineOperand::getReg(), LiveDebugValues::MLocTracker::getRegMLoc(), llvm::MachineOperand::isReg(), and MI.

◆ redefVar() [2/2]

void TransferTracker::redefVar	(	const MachineInstr &	MI,
		const DbgValueProperties &	Properties,
		Optional< LocIdx >	OptNewLoc
	)

inline

Handle a change in variable location within a block.

Terminate the variables current location, and record the value it now refers to, so that we can detect location transfers later on.

Definition at line 489 of file InstrRefBasedImpl.cpp.

◆ transferMlocs()

void TransferTracker::transferMlocs	(	LocIdx	Src,
		LocIdx	Dst,
		MachineBasicBlock::iterator	Pos
	)

inline

Transfer variables based on Src to be based on Dst.

This handles both register copies as well as spills and restores. Creates DBG_VALUEs describing the movement.

Definition at line 600 of file InstrRefBasedImpl.cpp.

References assert(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::clear(), LiveDebugValues::MLocTracker::emitLoc(), LiveDebugValues::ValueIDNum::EmptyValue, EmulateOldLDV, llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::end(), llvm::DenseMapBase< DenseMap< KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >, KeyT, ValueT, DenseMapInfo< KeyT >, llvm::detail::DenseMapPair< KeyT, ValueT > >::find(), MI, and LiveDebugValues::MLocTracker::readMLoc().

Member Data Documentation

◆ ActiveMLocs

DenseMap<LocIdx, SmallSet<DebugVariable, 4> > TransferTracker::ActiveMLocs

Map from LocIdxes to which DebugVariables are based that location.

Mantained while stepping through the block. Not accurate if VarLocs[Idx] != MTracker->LocIdxToIDNum[Idx].

Definition at line 211 of file InstrRefBasedImpl.cpp.

◆ ActiveVLocs

DenseMap<DebugVariable, LocAndProperties> TransferTracker::ActiveVLocs

Map from DebugVariable to it's current location and qualifying meta information.

To be used in conjunction with ActiveMLocs to construct enough information for the DBG_VALUEs for a particular LocIdx.

Definition at line 216 of file InstrRefBasedImpl.cpp.

◆ CalleeSavedRegs

const BitVector& TransferTracker::CalleeSavedRegs

Definition at line 243 of file InstrRefBasedImpl.cpp.

◆ MF

MachineFunction& TransferTracker::MF

Definition at line 182 of file InstrRefBasedImpl.cpp.

◆ MTracker

MLocTracker* TransferTracker::MTracker

This machine location tracker is assumed to always contain the up-to-date value mapping for all machine locations.

TransferTracker only reads information from it. (XXX make it const?)

Definition at line 181 of file InstrRefBasedImpl.cpp.

◆ PendingDbgValues

SmallVector<MachineInstr *, 4> TransferTracker::PendingDbgValues

Temporary cache of DBG_VALUEs to be entered into the Transfers collection.

Definition at line 219 of file InstrRefBasedImpl.cpp.

◆ ShouldEmitDebugEntryValues

bool TransferTracker::ShouldEmitDebugEntryValues

Definition at line 183 of file InstrRefBasedImpl.cpp.

◆ TII

const TargetInstrInfo* TransferTracker::TII

Definition at line 176 of file InstrRefBasedImpl.cpp.

◆ TLI

const TargetLowering* TransferTracker::TLI

Definition at line 177 of file InstrRefBasedImpl.cpp.

◆ Transfers

SmallVector<Transfer, 32> TransferTracker::Transfers

Collection of transfers (DBG_VALUEs) to be inserted.

Definition at line 200 of file InstrRefBasedImpl.cpp.

◆ TRI

const TargetRegisterInfo& TransferTracker::TRI

Definition at line 242 of file InstrRefBasedImpl.cpp.

◆ UseBeforeDefs

DenseMap<unsigned, SmallVector<UseBeforeDef, 1> > TransferTracker::UseBeforeDefs

Map from instruction index (within the block) to the set of UseBeforeDefs that become defined at that instruction.

Definition at line 235 of file InstrRefBasedImpl.cpp.

◆ UseBeforeDefVariables

DenseSet<DebugVariable> TransferTracker::UseBeforeDefVariables

The set of variables that are in UseBeforeDefs and can become a location once the relevant value is defined.

An element being erased from this collection prevents the use-before-def materializing.

Definition at line 240 of file InstrRefBasedImpl.cpp.

◆ VarLocs

SmallVector<ValueIDNum, 32> TransferTracker::VarLocs

Local cache of what-value-is-in-what-LocIdx.

Used to identify differences between TransferTrackers view of variable locations and MLocTrackers. For example, MLocTracker observes all clobbers, but TransferTracker lazily does not.

Definition at line 206 of file InstrRefBasedImpl.cpp.

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

lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp

Classes

Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ TransferTracker()

Member Function Documentation

◆ addUseBeforeDef()

◆ checkInstForNewValues()

◆ clobberMloc()

◆ emitMOLoc()

◆ flushDbgValues()

◆ isEntryValueValue()

◆ isEntryValueVariable()

◆ loadInlocs()

◆ recoverAsEntryValue()

◆ redefVar() [1/2]

◆ redefVar() [2/2]

◆ transferMlocs()

Member Data Documentation

◆ ActiveMLocs

◆ ActiveVLocs

◆ CalleeSavedRegs

◆ MF

◆ MTracker

◆ PendingDbgValues

◆ ShouldEmitDebugEntryValues

◆ TII

◆ TLI

◆ Transfers

◆ TRI

◆ UseBeforeDefs

◆ UseBeforeDefVariables

◆ VarLocs