#include <SpillPlacement.h>

Inheritance diagram for llvm::SpillPlacement:

Collaboration diagram for llvm::SpillPlacement:

Classes
struct	BlockConstraint
	BlockConstraint - Entry and exit constraints for a basic block. More...
struct	Node
Public Types
enum	BorderConstraint { DontCare, PrefReg, PrefSpill, PrefBoth, MustSpill }
Public Member Functions
	SpillPlacement ()
	~SpillPlacement ()
void	prepare (BitVector &RegBundles)
void	addConstraints (ArrayRef< BlockConstraint > LiveBlocks)
void	addPrefSpill (ArrayRef< unsigned > Blocks, bool Strong)
	addPrefSpill - Same as addConstraints(PrefSpill)
void	addLinks (ArrayRef< unsigned > Links)
	addLinks - Add transparent blocks with the given numbers.
bool	scanActiveBundles ()
void	iterate ()
ArrayRef< unsigned >	getRecentPositive ()
bool	finish ()
float	getBlockFrequency (unsigned Number) const
Static Public Attributes
static char	ID = 0

Detailed Description

Definition at line 41 of file SpillPlacement.h.

Member Enumeration Documentation

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 70 of file SpillPlacement.h.

Constructor & Destructor Documentation

llvm::SpillPlacement::SpillPlacement ( ) [inline]

Definition at line 65 of file SpillPlacement.h.

llvm::SpillPlacement::~SpillPlacement ( ) [inline]

Definition at line 66 of file SpillPlacement.h.

Member Function Documentation

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

addConstraints - Add constraints and biases. 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.

addConstraints - Compute node biases and weights from a set of constraints. Set a bit in NodeMask for each active node.

Definition at line 227 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::addBias(), llvm::ArrayRef< T >::begin(), DontCare, llvm::ArrayRef< T >::end(), getBlockFrequency(), llvm::EdgeBundles::getBundle(), HUGE_VALF, I, and llvm::ARM_AM::ib.

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

addLinks - Add transparent blocks with the given numbers.

Definition at line 271 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::addLink(), llvm::ArrayRef< T >::begin(), llvm::ArrayRef< T >::empty(), llvm::ArrayRef< T >::end(), getBlockFrequency(), llvm::EdgeBundles::getBundle(), I, llvm::ARM_AM::ib, llvm::SpillPlacement::Node::mustSpill(), and llvm::SmallVectorTemplateBase< T, isPodLike >::push_back().

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

addPrefSpill - Same as addConstraints(PrefSpill)

addPrefSpill - Add PrefSpill constraints to all blocks listed. 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 256 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::addBias(), llvm::ArrayRef< T >::begin(), llvm::ArrayRef< T >::end(), getBlockFrequency(), llvm::EdgeBundles::getBundle(), I, and llvm::ARM_AM::ib.

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 369 of file SpillPlacement.cpp.

References llvm::BitVector::find_first(), llvm::BitVector::find_next(), and llvm::BitVector::reset().

float llvm::SpillPlacement::getBlockFrequency ( unsigned Number ) const [inline]

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

Definition at line 142 of file SpillPlacement.h.

Referenced by addConstraints(), addLinks(), and addPrefSpill().

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 129 of file SpillPlacement.h.

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.

Parameters:

Linked - Numbers of linked nodes that need updating.

Definition at line 313 of file SpillPlacement.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::SmallVectorBase::empty(), llvm::SmallVectorTemplateCommon< T, typename >::end(), I, llvm::next(), llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), llvm::SmallVectorTemplateCommon< T, typename >::rbegin(), llvm::SmallVectorTemplateCommon< T, typename >::rend(), and llvm::SpillPlacement::Node::update().

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 359 of file SpillPlacement.cpp.

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

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 293 of file SpillPlacement.cpp.

References llvm::SmallVectorImpl< T >::clear(), llvm::SmallVectorBase::empty(), llvm::BitVector::find_first(), llvm::BitVector::find_next(), llvm::SmallVectorTemplateBase< T, isPodLike >::push_back(), and llvm::SpillPlacement::Node::update().

Member Data Documentation

char SpillPlacement::ID = 0 [static]

Definition at line 63 of file SpillPlacement.h.

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

Classes

Public Types

Public Member Functions

Static Public Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation