#include "llvm/CodeGen/SpillPlacement.h"

Classes
struct	BlockConstraint
	BlockConstraint - Entry and exit constraints for a basic block. More...

struct	Node
	Node - Each edge bundle corresponds to a Hopfield node. More...

Public Types
enum	BorderConstraint { DontCare , PrefReg , PrefSpill , PrefBoth , MustSpill }
	BorderConstraint - A basic block has separate constraints for entry and exit. More...

Public Member Functions
void	prepare (BitVector &RegBundles)
	prepare - Reset state and prepare for a new spill placement computation.

void	addConstraints (ArrayRef< BlockConstraint > LiveBlocks)
	addConstraints - Add constraints and biases.

void	addPrefSpill (ArrayRef< unsigned > Blocks, bool Strong)
	addPrefSpill - Add PrefSpill constraints to all blocks listed.

void	addLinks (ArrayRef< unsigned > Links)
	addLinks - Add transparent blocks with the given numbers.

bool	scanActiveBundles ()
	scanActiveBundles - Perform an initial scan of all bundles activated by addConstraints and addLinks, updating their state.

void	iterate ()
	iterate - Update the network iteratively until convergence, or new bundles are found.

ArrayRef< unsigned >	getRecentPositive ()
	getRecentPositive - Return an array of bundles that became positive during the previous call to scanActiveBundles or iterate.

bool	finish ()
	finish - Compute the optimal spill code placement given the constraints.

BlockFrequency	getBlockFrequency (unsigned Number) const
	getBlockFrequency - Return the estimated block execution frequency per function invocation.

bool	invalidate (MachineFunction &MF, const PreservedAnalyses &PA, MachineFunctionAnalysisManager::Invalidator &Inv)

	SpillPlacement (SpillPlacement &&)

	~SpillPlacement ()

Friends
class	SpillPlacementWrapperLegacy

class	SpillPlacementAnalysis

Detailed Description

Definition at line 45 of file SpillPlacement.h.

Member Enumeration Documentation

◆ BorderConstraint

enum llvm::SpillPlacement::BorderConstraint

BorderConstraint - A basic block has separate constraints for entry and exit.

Enumerator
DontCare	Block doesn't care / variable not live.
PrefReg	Block entry/exit prefers a register.
PrefSpill	Block entry/exit prefers a stack slot.
PrefBoth	Block entry prefers both register and stack.
MustSpill	A register is impossible, variable must be spilled.

Definition at line 81 of file SpillPlacement.h.

Constructor & Destructor Documentation

◆ SpillPlacement()

SpillPlacement::SpillPlacement ( SpillPlacement && )

default

◆ ~SpillPlacement()

SpillPlacement::~SpillPlacement ( )

default

Member Function Documentation

◆ addConstraints()

void SpillPlacement::addConstraints ( ArrayRef< BlockConstraint > LiveBlocks )

addConstraints - Add constraints and biases.

addConstraints - Compute node biases and weights from a set of constraints.

This method may be called more than once to accumulate constraints.

Parameters

LiveBlocks Constraints for blocks that have the variable live in or live out.

Set a bit in NodeMask for each active node.

Definition at line 292 of file SpillPlacement.cpp.

References DontCare, and llvm::EdgeBundles::getBundle().

◆ addLinks()

void SpillPlacement::addLinks ( ArrayRef< unsigned > Links )

addLinks - Add transparent blocks with the given numbers.

Definition at line 327 of file SpillPlacement.cpp.

References llvm::EdgeBundles::getBundle(), and llvm::Number.

◆ addPrefSpill()

void SpillPlacement::addPrefSpill	(	ArrayRef< unsigned >	Blocks,
		bool	Strong
	)

addPrefSpill - Add PrefSpill constraints to all blocks listed.

addPrefSpill - Same as addConstraints(PrefSpill)

This is equivalent to calling addConstraint with identical BlockConstraints with Entry = Exit = PrefSpill, and ChangesValue = false.

Parameters

Blocks	Array of block numbers that prefer to spill in and out.
Strong	When true, double the negative bias for these blocks.

Definition at line 313 of file SpillPlacement.cpp.

References B, Blocks, llvm::EdgeBundles::getBundle(), and PrefSpill.

◆ finish()

bool SpillPlacement::finish ( )

finish - Compute the optimal spill code placement given the constraints.

No MustSpill constraints will be violated, and the smallest possible number of PrefX constraints will be violated, weighted by expected execution frequencies. The selected bundles are returned in the bitvector passed to prepare().

Returns: True if a perfect solution was found, allowing the variable to be in a register through all relevant bundles.

Definition at line 395 of file SpillPlacement.cpp.

References assert(), llvm::BitVector::reset(), and llvm::BitVector::set_bits().

◆ getBlockFrequency()

BlockFrequency llvm::SpillPlacement::getBlockFrequency ( unsigned Number ) const

inline

getBlockFrequency - Return the estimated block execution frequency per function invocation.

Definition at line 156 of file SpillPlacement.h.

References llvm::Number.

◆ getRecentPositive()

ArrayRef< unsigned > llvm::SpillPlacement::getRecentPositive ( )

inline

getRecentPositive - Return an array of bundles that became positive during the previous call to scanActiveBundles or iterate.

Definition at line 143 of file SpillPlacement.h.

◆ invalidate()

bool SpillPlacementAnalysis::Result::invalidate	(	MachineFunction &	MF,
		const PreservedAnalyses &	PA,
		MachineFunctionAnalysisManager::Invalidator &	Inv
	)

Definition at line 212 of file SpillPlacement.cpp.

References llvm::PreservedAnalyses::getChecker(), and llvm::AnalysisManager< IRUnitT, ExtraArgTs >::Invalidator::invalidate().

◆ iterate()

void SpillPlacement::iterate ( )

iterate - Update the network iteratively until convergence, or new bundles are found.

iterate - Repeatedly update the Hopfield nodes until stability or the maximum number of iterations is reached.

Definition at line 366 of file SpillPlacement.cpp.

References llvm::SmallVectorImpl< T >::clear(), llvm::SparseSet< ValueT, KeyFunctorT, SparseT >::empty(), llvm::EdgeBundles::getNumBundles(), llvm::SparseSet< ValueT, KeyFunctorT, SparseT >::pop_back_val(), and llvm::SmallVectorTemplateBase< T, bool >::push_back().

◆ prepare()

void SpillPlacement::prepare ( BitVector & RegBundles )

prepare - Reset state and prepare for a new spill placement computation.

Parameters

RegBundles Bit vector to receive the edge bundles where the variable should be kept in a register. Each bit corresponds to an edge bundle, a set bit means the variable should be kept in a register through the bundle. A clear bit means the variable should be spilled. This vector is retained.

Definition at line 385 of file SpillPlacement.cpp.

References llvm::BitVector::clear(), llvm::SmallVectorImpl< T >::clear(), llvm::SparseSet< ValueT, KeyFunctorT, SparseT >::clear(), llvm::EdgeBundles::getNumBundles(), and llvm::BitVector::resize().

◆ scanActiveBundles()

bool SpillPlacement::scanActiveBundles ( )

scanActiveBundles - Perform an initial scan of all bundles activated by addConstraints and addLinks, updating their state.

Add all the bundles that now prefer a register to RecentPositive. Prepare internal data structures for iterate. Return true is there are any positive nodes.

Definition at line 343 of file SpillPlacement.cpp.

References llvm::SmallVectorImpl< T >::clear(), llvm::SmallVectorBase< Size_T >::empty(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::BitVector::set_bits().

Friends And Related Function Documentation

◆ SpillPlacementAnalysis

friend class SpillPlacementAnalysis

friend

Definition at line 47 of file SpillPlacement.h.

◆ SpillPlacementWrapperLegacy

friend class SpillPlacementWrapperLegacy

friend

Definition at line 46 of file SpillPlacement.h.

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

include/llvm/CodeGen/SpillPlacement.h
lib/CodeGen/SpillPlacement.cpp

Classes

Public Types

Public Member Functions

Friends

Detailed Description

Member Enumeration Documentation

◆ BorderConstraint

Constructor & Destructor Documentation

◆ SpillPlacement()

◆ ~SpillPlacement()

Member Function Documentation

◆ addConstraints()

◆ addLinks()

◆ addPrefSpill()

◆ finish()

◆ getBlockFrequency()

◆ getRecentPositive()

◆ invalidate()

◆ iterate()

◆ prepare()

◆ scanActiveBundles()

Friends And Related Function Documentation

◆ SpillPlacementAnalysis

◆ SpillPlacementWrapperLegacy