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edu.umd.cs.findbugs.ba.obl
Class ObligationAnalysis

java.lang.Object
  extended by edu.umd.cs.findbugs.ba.BasicAbstractDataflowAnalysis<Fact>
      extended by edu.umd.cs.findbugs.ba.AbstractDataflowAnalysis<Fact>
          extended by edu.umd.cs.findbugs.ba.ForwardDataflowAnalysis<StateSet>
              extended by edu.umd.cs.findbugs.ba.obl.ObligationAnalysis
All Implemented Interfaces:
DataflowAnalysis<StateSet>

public class ObligationAnalysis
extends ForwardDataflowAnalysis<StateSet>

Dataflow analysis to track obligations (i/o streams and other resources which must be closed).

See Weimer and Necula, Finding and preventing run-time error handling mistakes, OOPSLA 2004.

Author:
David Hovemeyer

Constructor Summary
ObligationAnalysis(DepthFirstSearch dfs, XMethod xmethod, org.apache.bcel.generic.ConstantPoolGen cpg, ObligationFactory factory, ObligationPolicyDatabase database, TypeDataflow typeDataflow, IsNullValueDataflow invDataflow, IErrorLogger errorLogger)
          Constructor.
 
Method Summary
 void copy(StateSet src, StateSet dest)
          Copy dataflow facts.
 StateSet createFact()
          Create empty (uninitialized) dataflow facts for one program point.
 void edgeTransfer(Edge edge, StateSet fact)
          Edge transfer function.
 InstructionActionCache getActionCache()
           
 void initEntryFact(StateSet fact)
          Initialize the "entry" fact for the graph.
 boolean isFactValid(StateSet fact)
          Determine whether the given fact is valid (neither top nor bottom).
 boolean isTop(StateSet fact)
          Is the given fact the top value.
 void makeFactTop(StateSet fact)
          Make given fact the top value.
 void meetInto(StateSet fact, Edge edge, StateSet result)
          Meet a dataflow fact associated with an incoming edge into another fact.
 boolean same(StateSet a, StateSet b)
          Are given dataflow facts the same?
 void transfer(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle end, StateSet start, StateSet result)
          Transfer function for the analysis.
 void transferInstruction(org.apache.bcel.generic.InstructionHandle handle, BasicBlock basicBlock, StateSet fact)
          Transfer function for a single instruction.
 
Methods inherited from class edu.umd.cs.findbugs.ba.ForwardDataflowAnalysis
getBlockOrder, getDepthFirstSearch, isForwards
 
Methods inherited from class edu.umd.cs.findbugs.ba.AbstractDataflowAnalysis
getFactAfterLocation, getFactAtLocation
 
Methods inherited from class edu.umd.cs.findbugs.ba.BasicAbstractDataflowAnalysis
factToString, finishIteration, getFactOnEdge, getLastUpdateTimestamp, getResultFact, getStartFact, resultFactIterator, setLastUpdateTimestamp, startIteration
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ObligationAnalysis

public ObligationAnalysis(DepthFirstSearch dfs,
                          XMethod xmethod,
                          org.apache.bcel.generic.ConstantPoolGen cpg,
                          ObligationFactory factory,
                          ObligationPolicyDatabase database,
                          TypeDataflow typeDataflow,
                          IsNullValueDataflow invDataflow,
                          IErrorLogger errorLogger)
Constructor.

Parameters:
dfs - a DepthFirstSearch on the method to be analyzed
xmethod - method to analyze
cpg - ConstantPoolGen of the method to be analyzed
factory - the ObligationFactory defining the obligation types
database - the PolicyDatabase defining the methods which add and delete obligations
errorLogger - callback to use when reporting missing classes
Method Detail

getActionCache

public InstructionActionCache getActionCache()

createFact

public StateSet createFact()
Description copied from interface: DataflowAnalysis
Create empty (uninitialized) dataflow facts for one program point. A valid value will be copied into it before it is used.


isFactValid

public boolean isFactValid(StateSet fact)
Description copied from class: AbstractDataflowAnalysis
Determine whether the given fact is valid (neither top nor bottom).

Specified by:
isFactValid in class AbstractDataflowAnalysis<StateSet>

transferInstruction

public void transferInstruction(org.apache.bcel.generic.InstructionHandle handle,
                                BasicBlock basicBlock,
                                StateSet fact)
                         throws DataflowAnalysisException
Description copied from class: AbstractDataflowAnalysis
Transfer function for a single instruction.

Specified by:
transferInstruction in class AbstractDataflowAnalysis<StateSet>
Parameters:
handle - the instruction
basicBlock - the BasicBlock containing the instruction; needed to disambiguate instructions in inlined JSR subroutines
fact - which should be modified based on the instruction
Throws:
DataflowAnalysisException

transfer

public void transfer(BasicBlock basicBlock,
                     @CheckForNull
                     org.apache.bcel.generic.InstructionHandle end,
                     StateSet start,
                     StateSet result)
              throws DataflowAnalysisException
Description copied from interface: DataflowAnalysis
Transfer function for the analysis. Taking dataflow facts at start (which might be either the entry or exit of the block, depending on whether the analysis is forwards or backwards), modify result to be the facts at the other end of the block.

Specified by:
transfer in interface DataflowAnalysis<StateSet>
Overrides:
transfer in class AbstractDataflowAnalysis<StateSet>
Parameters:
basicBlock - the basic block
end - if nonnull, stop before considering this instruction; otherwise, consider all of the instructions in the basic block
start - dataflow facts at beginning of block (if forward analysis) or end of block (if backwards analysis)
result - resulting dataflow facts at other end of block
Throws:
DataflowAnalysisException

edgeTransfer

public void edgeTransfer(Edge edge,
                         StateSet fact)
                  throws DataflowAnalysisException
Description copied from interface: DataflowAnalysis
Edge transfer function. Modify the given fact that is true on the (logical) edge source to modify it so that it is true at the (logical) edge target.

A do-nothing implementation is legal, and appropriate for analyses where branches are not significant.

Specified by:
edgeTransfer in interface DataflowAnalysis<StateSet>
Overrides:
edgeTransfer in class BasicAbstractDataflowAnalysis<StateSet>
Parameters:
edge - the Edge
fact - a dataflow fact
Throws:
DataflowAnalysisException

copy

public void copy(StateSet src,
                 StateSet dest)
Description copied from interface: DataflowAnalysis
Copy dataflow facts.


initEntryFact

public void initEntryFact(StateSet fact)
                   throws DataflowAnalysisException
Description copied from interface: DataflowAnalysis
Initialize the "entry" fact for the graph.

Throws:
DataflowAnalysisException

makeFactTop

public void makeFactTop(StateSet fact)
Description copied from interface: DataflowAnalysis
Make given fact the top value.


isTop

public boolean isTop(StateSet fact)
Description copied from interface: DataflowAnalysis
Is the given fact the top value.


same

public boolean same(StateSet a,
                    StateSet b)
Description copied from interface: DataflowAnalysis
Are given dataflow facts the same?


meetInto

public void meetInto(StateSet fact,
                     Edge edge,
                     StateSet result)
              throws DataflowAnalysisException
Description copied from interface: DataflowAnalysis
Meet a dataflow fact associated with an incoming edge into another fact. This is used to determine the start fact for a basic block.

Parameters:
fact - the predecessor fact (incoming edge)
edge - the edge from the predecessor
result - the result fact
Throws:
DataflowAnalysisException

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