de.rwth.dfa.jvm
Class Solver

java.lang.Object
  |
  +--de.rwth.dfa.jvm.Solver

Direct Known Subclasses:

ExecutionSolver, GraphSolver

public abstract class Solver

extends java.lang.Object

An abstract class for a JVM abstraction solver. It contains the basic data structures describing the JVM abstraction and the method to be analyzed. Furthermore, it provides the general framework for runtime and memory statistics. To get a working implementation, the method compute() must be provided. Implementations should guarantee that all computation is done there and not in constructors!. Otherwise, the statistics will be wrong.

Version:

$Id: Solver.java,v 1.2 2002/09/17 06:53:53 mohnen Exp $

Author:

Markus Mohnen

Field Summary

protected Abstraction	abstraction The JVM abstraction of this solver.
protected long	iterations The number of iterations used by the computation.
protected long	memory The approximation of the amount of memory used by the solution.
protected de.fub.bytecode.classfile.CodeException[]	methodExceptions The code exception array of the method to be analyses.
protected de.fub.bytecode.generic.InstructionList	methodInstrs The instruction list of the method to be analyses.
protected java.lang.String	methodName The name of the method to be analyses.
protected Stopwatch	stopwatch The stop watch to be used for timing the computation.

Constructor Summary

Solver(Abstraction abstraction, java.lang.String methodName, de.fub.bytecode.generic.InstructionList methodInstrs, de.fub.bytecode.classfile.CodeException[] methodExceptions)
Creates a new Solver instance without stop watch.

Solver(Abstraction abstraction, java.lang.String methodName, de.fub.bytecode.generic.InstructionList methodInstrs, de.fub.bytecode.classfile.CodeException[] methodExceptions, Stopwatch stopwatch)
Creates a new Solver instance with stop watch.

Method Summary

protected abstract void	compute(java.lang.Object[] solution, boolean isForward, boolean isAll) Implementations must provide this method.
long	getIterations() Returns the number of iterations during the computation.
long	getMemory() Returns an approximation of the amount of memory used during the computation.
java.lang.Object[]	getSolution() Computes the solution by calling compute() and does memory and timing statistics.

Methods inherited from class java.lang.Object

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

Field Detail

abstraction

protected Abstraction abstraction

The JVM abstraction of this solver.

methodName

protected java.lang.String methodName

The name of the method to be analyses.

methodInstrs

protected de.fub.bytecode.generic.InstructionList methodInstrs

The instruction list of the method to be analyses.

methodExceptions

protected de.fub.bytecode.classfile.CodeException[] methodExceptions

The code exception array of the method to be analyses.

stopwatch

protected Stopwatch stopwatch

The stop watch to be used for timing the computation. This may be null if there is no stop watch to be used.

iterations

protected long iterations

The number of iterations used by the computation.

memory

protected long memory

The approximation of the amount of memory used by the solution.

Constructor Detail

Solver

public Solver(Abstraction abstraction,
              java.lang.String methodName,
              de.fub.bytecode.generic.InstructionList methodInstrs,
              de.fub.bytecode.classfile.CodeException[] methodExceptions,
              Stopwatch stopwatch)

Creates a new Solver instance with stop watch.

Parameters:

abstraction - an Abstraction value

methodName - a String value

methodInstrs - an InstructionList value

methodExceptions - a CodeException[] value

stopwatch - a Stopwatch value

Solver

public Solver(Abstraction abstraction,
              java.lang.String methodName,
              de.fub.bytecode.generic.InstructionList methodInstrs,
              de.fub.bytecode.classfile.CodeException[] methodExceptions)

Creates a new Solver instance without stop watch.

Parameters:

abstraction - an Abstraction value

methodName - a String value

methodInstrs - an InstructionList value

methodExceptions - a CodeException[] value

Method Detail

compute

protected abstract void compute(java.lang.Object[] solution,
                                boolean isForward,
                                boolean isAll)

Implementations must provide this method. Given the JVM abstraction and the method in this classes data structures, the method must compute a correct solution, i.e. an approximation of the meet over paths solution (for isAll==true). This method is called from getSolution().

1. Implementations must set the variable iterations to a sensible value.
2. If there is a stop watch, it is already running. Implementations of this method may use the split() method as often as they wish. They may not call start() or stop().
3. An approximation of the memory usage is done by getSolution(). Hence, setting memory in this method has no effect.

Parameters:

solution - an Object[] value: A newly created array for the solution. It has one entry for each instruction.

isForward - a boolean value: Analysis control flow

isAll - a boolean value: Use meet or join

getSolution

public java.lang.Object[] getSolution()

Computes the solution by calling compute() and does memory and timing statistics.

Returns:

an Object[] value

getIterations

public long getIterations()

Returns the number of iterations during the computation.

Returns:

a long value

getMemory

public long getMemory()

Returns an approximation of the amount of memory used during the computation.

Returns:

a long value