LLVM: llvm::SpillPlacement Class Reference (original) (raw)

#include "[llvm/CodeGen/SpillPlacement.h](SpillPlacement%5F8h%5Fsource.html)"

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 ()

Definition at line 45 of file SpillPlacement.h.

◆ 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.

References SpillPlacement().

Referenced by SpillPlacement().

◆ ~SpillPlacement()

SpillPlacement::~SpillPlacement ( ) default

◆ addConstraints()

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.

◆ addPrefSpill()

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(), 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().

◆ getBlockFrequency()

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

Definition at line 156 of file SpillPlacement.h.

References llvm::Number.

◆ getRecentPositive()

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()

◆ 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.

◆ 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().

◆ 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.

◆ SpillPlacementAnalysis

◆ SpillPlacementWrapperLegacy

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