Package edu.umd.cs.findbugs.ba

Interface DataflowAnalysis<Fact>

All Known Implementing Classes:
AbstractDataflowAnalysis, AbstractDominatorsAnalysis, BackwardDataflowAnalysis, BackwardTypeQualifierDataflowAnalysis, BasicAbstractDataflowAnalysis, BlockTypeAnalysis, CallListAnalysis, ConstantAnalysis, DominatorsAnalysis, FieldSetAnalysis, ForwardDataflowAnalysis, ForwardTypeQualifierDataflowAnalysis, FrameDataflowAnalysis, IsNullValueAnalysis, LiveLocalStoreAnalysis, LoadAnalysis, LockAnalysis, NonExceptionDominatorsAnalysis, NonExceptionPostDominatorsAnalysis, NonImplicitExceptionDominatorsAnalysis, NonImplicitExceptionPostDominatorsAnalysis, ObligationAnalysis, PostDominatorsAnalysis, ResourceValueAnalysis, ReturnPathAnalysis, ReturnPathTypeAnalysis, StackDepthAnalysis, StoreAnalysis, TypeAnalysis, TypeQualifierDataflowAnalysis, UnconditionalValueDerefAnalysis, ValueNumberAnalysis
public interface DataflowAnalysis<Fact>
A dataflow analysis to be used with the Dataflow class.

In order to avoid duplicating functionality (such as caching of start and result facts), most analyses should extend the BasicAbstractDataflowAnalysis or AbstractDataflowAnalysis classes rather than directly implementing this interface.

Author:
David Hovemeyer
See Also:

  • Method Details

    • createFact

      Fact createFact()
      Create empty (uninitialized) dataflow facts for one program point. A valid value will be copied into it before it is used.

    • getStartFact

      Fact getStartFact(BasicBlock block)
      Get the start fact for given basic block.
      Parameters:
      block - the basic block

    • getResultFact

      Fact getResultFact(BasicBlock block)
      Get the result fact for given basic block.
      Parameters:
      block - the basic block

    • getFactAtLocation

      Fact getFactAtLocation(Location location) throws DataflowAnalysisException
      Get dataflow fact at (just before) given Location. Note "before" is meant in the logical sense, so for backward analyses, before means after the location in the control flow sense.
      Parameters:
      location - the Location
      Returns:
      the dataflow value at given Location
      Throws:
      DataflowAnalysisException

    • getFactAfterLocation

      Fact getFactAfterLocation(Location location) throws DataflowAnalysisException
      Get the dataflow fact representing the point just after given Location. Note "after" is meant in the logical sense, so for backward analyses, after means before the location in the control flow sense.
      Parameters:
      location - the Location
      Returns:
      the dataflow value after given Location
      Throws:
      DataflowAnalysisException

    • getFactOnEdge

      Fact getFactOnEdge(Edge edge) throws DataflowAnalysisException
      Get the fact that is true on the given control edge.
      Parameters:
      edge - the edge
      Returns:
      the fact that is true on the edge
      Throws:
      DataflowAnalysisException

    • copy

      void copy(Fact source, Fact dest)
      Copy dataflow facts.

    • initEntryFact

      void initEntryFact(Fact result) throws DataflowAnalysisException
      Initialize the "entry" fact for the graph.
      Throws:
      DataflowAnalysisException

    • makeFactTop

      void makeFactTop(Fact fact)
      Make given fact the top value.

    • isTop

      boolean isTop(Fact fact)
      Is the given fact the top value.

    • isForwards

      boolean isForwards()
      Returns true if the analysis is forwards, false if backwards.

    • getBlockOrder

      BlockOrder getBlockOrder(CFG cfg)
      Return the BlockOrder specifying the order in which BasicBlocks should be visited in the main dataflow loop.
      Parameters:
      cfg - the CFG upon which we're performing dataflow analysis

    • same

      boolean same(Fact fact1, Fact fact2)
      Are given dataflow facts the same?

    • transfer

      void transfer(BasicBlock basicBlock, @CheckForNull org.apache.bcel.generic.InstructionHandle end, Fact start, Fact result) throws DataflowAnalysisException
      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.
      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

      void edgeTransfer(Edge edge, Fact fact) throws DataflowAnalysisException
      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.

      Parameters:
      edge - the Edge
      fact - a dataflow fact
      Throws:
      DataflowAnalysisException

    • meetInto

      void meetInto(Fact fact, Edge edge, Fact result) throws DataflowAnalysisException
      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

    • startIteration

      void startIteration()
      Called before beginning an iteration of analysis. Each iteration visits every basic block in the CFG.

    • finishIteration

      void finishIteration()
      Called after finishing an iteration of analysis.

    • getLastUpdateTimestamp

      int getLastUpdateTimestamp(Fact fact)

    • setLastUpdateTimestamp

      void setLastUpdateTimestamp(Fact fact, int timestamp)

    • factToString

      String factToString(Fact fact)
      Return a String representation of given Fact. For debugging purposes.
      Parameters:
      fact - a dataflow fact
      Returns:
      String representation of the fact