Class PatternMatcher

java.lang.Object

edu.umd.cs.findbugs.ba.bcp.PatternMatcher

All Implemented Interfaces:

DFSEdgeTypes, DFSEdgeTypes

public class PatternMatcher
extends Object
implements DFSEdgeTypes

Match a ByteCodePattern against the code of a method, represented by a CFG. Produces some number of ByteCodePatternMatch objects, which indicate how the pattern matched the bytecode instructions in the method.

This code is a hack and should probably be rewritten.

See Also:

• ByteCodePattern

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	PatternMatcher.State	Object representing the current state of the matching algorithm.

Field Summary

Fields

Modifier and Type	Field	Description
private final CFG	cfg
private final org.apache.bcel.generic.ConstantPoolGen	cpg
(package private) int	depth	Match a sequence of pattern elements, starting at the given one.
private final DepthFirstSearch	dfs
private final DominatorsAnalysis	domAnalysis
private static final org.slf4j.Logger	LOG
private int	nextPath
private final ByteCodePattern	pattern
private final LinkedList<ByteCodePatternMatch>	resultList
private static final boolean	SHOW_WILD
private final IdentityHashMap<BasicBlock, BasicBlock>	visitedBlockMap
private final ValueNumberDataflow	vnaDataflow
private final LinkedList<BasicBlock>	workList

Fields inherited from interface DFSEdgeTypes

BACK_EDGE, CROSS_EDGE, FORWARD_EDGE, TREE_EDGE, UNKNOWN_EDGE

Constructor Summary

Constructors

Constructor	Description
PatternMatcher(ByteCodePattern pattern, ClassContext classContext, org.apache.bcel.classfile.Method method)	Constructor.

Method Summary

Modifier and Type	Method	Description
private void	attemptMatch(BasicBlock basicBlock, BasicBlock.InstructionIterator instructionIterator)	Attempt to begin a match.
Iterator<ByteCodePatternMatch>	byteCodePatternMatchIterator()	Return an Iterator over the ByteCodePatternMatch objects representing successful matches of the ByteCodePattern.
private void	debug(String s)
PatternMatcher	execute()	Search for examples of the ByteCodePattern.
private void	work(PatternMatcher.State state)

Methods inherited from class Object

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

Field Details

LOG

private static final org.slf4j.Logger LOG

SHOW_WILD

private static final boolean SHOW_WILD

pattern

private final ByteCodePattern pattern

cfg

private final CFG cfg

cpg

private final org.apache.bcel.generic.ConstantPoolGen cpg

dfs

private final DepthFirstSearch dfs

vnaDataflow

private final ValueNumberDataflow vnaDataflow

domAnalysis

private final DominatorsAnalysis domAnalysis

workList

private final LinkedList<BasicBlock> workList

visitedBlockMap

private final IdentityHashMap<BasicBlock, BasicBlock> visitedBlockMap

resultList

private final LinkedList<ByteCodePatternMatch> resultList

nextPath

private int nextPath

depth

int depth

Match a sequence of pattern elements, starting at the given one. The InstructionIterator should generally be positioned just before the next instruction to be matched. However, it may be positioned at the end of a basic block, in which case nothing will happen except that we will try to continue the match in the non-backedge successors of the basic block.

Constructor Details

PatternMatcher

public PatternMatcher(ByteCodePattern pattern,
 ClassContext classContext,
 org.apache.bcel.classfile.Method method)
               throws CFGBuilderException,
DataflowAnalysisException

Constructor.

Parameters:

pattern - the ByteCodePattern to look for examples of

classContext - ClassContext for the class to analyze

method - the Method to analyze

Throws:

CFGBuilderException

DataflowAnalysisException

Method Details

execute

public PatternMatcher execute()
                       throws DataflowAnalysisException

Search for examples of the ByteCodePattern.

Returns:

this object

Throws:

DataflowAnalysisException - if the ValueNumberAnalysis did not produce useful values for the method

byteCodePatternMatchIterator

public Iterator<ByteCodePatternMatch> byteCodePatternMatchIterator()

Return an Iterator over the ByteCodePatternMatch objects representing successful matches of the ByteCodePattern.

attemptMatch

private void attemptMatch(BasicBlock basicBlock,
 BasicBlock.InstructionIterator instructionIterator)
                   throws DataflowAnalysisException

Attempt to begin a match.

Parameters:

basicBlock - the basic block

instructionIterator - the instruction iterator positioned just before the first instruction to be matched

Throws:

DataflowAnalysisException

debug

private void debug(String s)

work

private void work(PatternMatcher.State state)
           throws DataflowAnalysisException

Throws:

DataflowAnalysisException