Package EDU.purdue.cs.bloat.codegen

Class RegisterAllocator

java.lang.Object

EDU.purdue.cs.bloat.codegen.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

Constructor Summary

Constructors

Constructor	Description
RegisterAllocator(FlowGraph cfg, Liveness liveness)	Constructor.

Method Summary

Modifier and Type	Method	Description
int	maxLocals()	Returns the maximum number of local variables used by the cfg after its "registers" (local variables) have been allocated.
LocalVariable	newLocal(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

Constructor Detail

RegisterAllocator

public RegisterAllocator(FlowGraph cfg,
                         Liveness 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

Method Detail

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 LocalVariable newLocal(Type type)

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