com.ibm.wala.analysis.stackMachine
Class AbstractIntStackMachine

java.lang.Object
  com.ibm.wala.analysis.stackMachine.AbstractIntStackMachine

All Implemented Interfaces:

FixedPointConstants

Direct Known Subclasses:

SSABuilder

public abstract class AbstractIntStackMachine
extends java.lang.Object
implements FixedPointConstants

Skeleton of functionality to propogate information through the Java bytecode stack machine using ShrikeBT. This class computes properties the Java operand stack and of the local variables at the beginning of each basic block. In this implementation, each dataflow variable value is an integer, and the "meeter" object provides the meets

Nested Class Summary

protected static class	AbstractIntStackMachine.BasicStackFlowProvider This gives some basic facilities for shoving things around on the stack.
static interface	AbstractIntStackMachine.FlowProvider Interface which defines a flow function for a basic block
class	AbstractIntStackMachine.MachineState Representation of the state of the JVM stack machine at some program point.
protected static interface	AbstractIntStackMachine.Meeter A Meeter object provides the dataflow logic needed to meet the abstract machine state for a dataflow meet.

Field Summary

static int	BOTTOM
static int	IGNORE
protected int	maxLocals the max number of locals in play
static boolean	OPTIMISTIC Should uninitialized variables be considered TOP (optimistic) or BOTTOM (pessimistic);
static int	TOP
static int	UNANALYZED

Fields inherited from interface com.ibm.wala.fixpoint.FixedPointConstants

CHANGED, CHANGED_AND_FIXED, CHANGED_MASK, FIXED_MASK, NOT_CHANGED, NOT_CHANGED_AND_FIXED, SIDE_EFFECT_MASK

Constructor Summary

protected

AbstractIntStackMachine(ShrikeCFG G)

Method Summary

int[]	allocateNewLocalsArray()
AbstractIntStackMachine.MachineState	getEntryState()
AbstractIntStackMachine.MachineState	getIn(ShrikeCFG.BasicBlock bb)
protected void	init(AbstractIntStackMachine.Meeter meeter, AbstractIntStackMachine.FlowProvider flow)
protected void	initializeVariables() Convenience method ...
boolean	solve()

Methods inherited from class java.lang.Object

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

Field Detail

TOP

public static final int TOP

See Also:

Constant Field Values

BOTTOM

public static final int BOTTOM

See Also:

Constant Field Values

UNANALYZED

public static final int UNANALYZED

See Also:

Constant Field Values

IGNORE

public static final int IGNORE

See Also:

Constant Field Values

maxLocals

protected final int maxLocals

the max number of locals in play

OPTIMISTIC

public static final boolean OPTIMISTIC

Should uninitialized variables be considered TOP (optimistic) or BOTTOM (pessimistic);

See Also:

Constant Field Values

Constructor Detail

AbstractIntStackMachine

protected AbstractIntStackMachine(ShrikeCFG G)

Method Detail

init

protected void init(AbstractIntStackMachine.Meeter meeter,
                    AbstractIntStackMachine.FlowProvider flow)

Parameters:

meeter -

flow -

solve

public boolean solve()

initializeVariables

protected void initializeVariables()

Convenience method ... a little ugly .. perhaps delete later.

getEntryState

public AbstractIntStackMachine.MachineState getEntryState()

getIn

public AbstractIntStackMachine.MachineState getIn(ShrikeCFG.BasicBlock bb)

Returns:

the state at the entry to a given block

allocateNewLocalsArray

public int[] allocateNewLocalsArray()