sandmark.watermark.potkonjak
Class RegisterAllocator

java.lang.Object
  |
  +--sandmark.watermark.potkonjak.RegisterAllocator

public class RegisterAllocator

extends java.lang.Object

RegisterAllocator performs analysis on a control flow graph and determines the minimum amount of local variables needed in a method.

See Also:

LocalVariable

Nested Class Summary

(package private) class

RegisterAllocator.IGNode IGNode is a node in the interference graph.

Field Summary

(package private) EDU.purdue.cs.bloat.cfg.FlowGraph	cfg
(package private) java.util.Vector	coloring
(package private) java.util.Map	colors
(package private) int	colorsUsed
(package private) EDU.purdue.cs.bloat.util.Graph	ig
(package private) livenessAnalysis	liveness
(package private) static float	LOOP_FACTOR
(package private) static int	MAX_DEPTH
(package private) static float	MAX_WEIGHT

Constructor Summary

RegisterAllocator(EDU.purdue.cs.bloat.cfg.FlowGraph cfg, livenessAnalysis liveness)
Constructor.

RegisterAllocator(EDU.purdue.cs.bloat.cfg.FlowGraph cfg, livenessAnalysis liveness, java.util.Vector coloring, livenessAnalysis.IGNode[] sortedNodes)
This constructor was added so that a specific coloring could be passed.

Method Summary

EDU.purdue.cs.bloat.util.Graph	getRegIG()
int	maxLocals() Returns the maximum number of local variables used by the cfg after its "registers" (local variables) have been allocated.
EDU.purdue.cs.bloat.editor.LocalVariable	newLocal(EDU.purdue.cs.bloat.editor.Type type) Creates a new local variable in this method (as modeled by the cfg).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

cfg

EDU.purdue.cs.bloat.cfg.FlowGraph cfg

liveness

livenessAnalysis liveness

coloring

java.util.Vector coloring

colors

java.util.Map colors

colorsUsed

int colorsUsed

MAX_WEIGHT

static final float MAX_WEIGHT

See Also:

Constant Field Values

LOOP_FACTOR

static final float LOOP_FACTOR

See Also:

Constant Field Values

MAX_DEPTH

static final int MAX_DEPTH

ig

final EDU.purdue.cs.bloat.util.Graph ig

Constructor Detail

RegisterAllocator

public RegisterAllocator(EDU.purdue.cs.bloat.cfg.FlowGraph cfg,
                         livenessAnalysis liveness)

Constructor. Builds an interference graph based on the expression nodes found in liveness. Traverses the graph and determines which nodes needs to be precolored and which nodes can be coalesced (move statements). Nodes are coalesced and local variables are assigned to expressions.

See Also:

FlowGraph, LocalVariable

RegisterAllocator

public RegisterAllocator(EDU.purdue.cs.bloat.cfg.FlowGraph cfg,
                         livenessAnalysis liveness,
                         java.util.Vector coloring,
                         livenessAnalysis.IGNode[] sortedNodes)

This constructor was added so that a specific coloring could be passed. The vector coloring along with an array of sorted nodes are passed to the constructor so that the specific coloring can be assigned to the local variables.

Method Detail

getRegIG

public EDU.purdue.cs.bloat.util.Graph getRegIG()

maxLocals

public int maxLocals()

Returns the maximum number of local variables used by the cfg after its "registers" (local variables) have been allocated.

newLocal

public EDU.purdue.cs.bloat.editor.LocalVariable newLocal(EDU.purdue.cs.bloat.editor.Type type)

Creates a new local variable in this method (as modeled by the cfg). Updates the number of local variables appropriately.