Package org.checkerframework.dataflow.analysis

Class BackwardAnalysisImpl<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>

java.lang.Object
org.checkerframework.dataflow.analysis.AbstractAnalysis<V,S,T>
org.checkerframework.dataflow.analysis.BackwardAnalysisImpl<V,S,T>
Type Parameters:
V - the abstract value type to be tracked by the analysis
S - the store type used in the analysis
T - the transfer function type that is used to approximate runtime behavior
All Implemented Interfaces:
Analysis<V,S,T>, BackwardAnalysis<V,S,T>
public class BackwardAnalysisImpl<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>> extends AbstractAnalysis<V,S,T> implements BackwardAnalysis<V,S,T>
An implementation of a backward analysis to solve a org.checkerframework.dataflow problem given a control flow graph and a backward transfer function.

  • Field Details

    • outStores

      protected final IdentityHashMap<Block,S extends Store<S>> outStores
      Out stores after every basic block (assumed to be 'no information' if not present).

    • exceptionStores

      protected final IdentityHashMap<ExceptionBlock,S extends Store<S>> exceptionStores
      Exception store of an exception block, propagated by exceptional successors of its exception block, and merged with the normal TransferResult.

    • storeAtEntry

      protected @Nullable S extends Store<S> storeAtEntry
      The store right before the entry block.

  • Constructor Details

    • BackwardAnalysisImpl

      public BackwardAnalysisImpl()
      Construct an object that can perform a org.checkerframework.dataflow backward analysis over a control flow graph. When using this constructor, the transfer function is set later by the subclass, e.g., org.checkerframework.framework.flow.CFAbstractAnalysis.

    • BackwardAnalysisImpl

      public BackwardAnalysisImpl(T transferFunction)
      Construct an object that can perform a org.checkerframework.dataflow backward analysis over a control flow graph given a transfer function.
      Parameters:
      transferFunction - the transfer function

  • Method Details

    • performAnalysis

      public void performAnalysis(ControlFlowGraph cfg)
      Description copied from interface: Analysis
      Perform the actual analysis.
      Specified by:
      performAnalysis in interface Analysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>
      Parameters:
      cfg - the control flow graph

    • performAnalysisBlock

      public void performAnalysisBlock(Block b)
      Description copied from interface: Analysis
      Perform the actual analysis on one block.
      Specified by:
      performAnalysisBlock in interface Analysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>
      Parameters:
      b - the block to analyze

    • getInput

      public @Nullable TransferInput<V,S> getInput(Block b)
      Description copied from interface: Analysis
      Get the transfer input of a given Block b.
      Specified by:
      getInput in interface Analysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>
      Parameters:
      b - a given Block
      Returns:
      the transfer input of this Block

    • getEntryStore

      public @Nullable S getEntryStore()
      Description copied from interface: BackwardAnalysis
      Get the output store at the entry block of a given control flow graph. For a backward analysis, the output store contains the analyzed flow information from the exit block to the entry block.
      Specified by:
      getEntryStore in interface BackwardAnalysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>
      Returns:
      the output store at the entry block of a given control flow graph

    • initFields

      protected void initFields(ControlFlowGraph cfg)
      Description copied from class: AbstractAnalysis
      Initialize fields of this object based on a given control flow graph. Sub-class may override this method to initialize customized fields.
      Overrides:
      initFields in class AbstractAnalysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>
      Parameters:
      cfg - a given control flow graph

    • initInitialInputs

      @RequiresNonNull("cfg") protected void initInitialInputs()
      Description copied from class: AbstractAnalysis
      Initialize the transfer inputs of every basic block before performing the analysis.
      Specified by:
      initInitialInputs in class AbstractAnalysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>

    • propagateStoresTo

      protected void propagateStoresTo(Block pred, @Nullable Node node, TransferInput<V,S> currentInput, Store.FlowRule flowRule, boolean addToWorklistAgain)
      Description copied from class: AbstractAnalysis
      Propagate the stores in currentInput to the next block in the direction of analysis, according to the flowRule.
      Specified by:
      propagateStoresTo in class AbstractAnalysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>
      Parameters:
      pred - the target block to propagate the stores to
      node - the node of the target block
      currentInput - the current transfer input
      flowRule - the flow rule being used
      addToWorklistAgain - whether the block should be added to AbstractAnalysis.worklist again

    • addStoreAfter

      protected void addStoreAfter(Block pred, @Nullable Node node, S s, boolean addBlockToWorklist)
      Add a store after the basic block pred by merging with the existing stores for that location.
      Parameters:
      pred - the basic block
      node - the node of the basic block b
      s - the store being added
      addBlockToWorklist - whether the basic block b should be added back to Worklist

    • getStoreAfter

      protected @Nullable S getStoreAfter(Block b)
      Returns the store corresponding to the location right after the basic block b.
      Parameters:
      b - the given block
      Returns:
      the store right after the given block

    • runAnalysisFor

      public S runAnalysisFor(@FindDistinct Node node, Analysis.BeforeOrAfter preOrPost, TransferInput<V,S> blockTransferInput, IdentityHashMap<Node,V> nodeValues, @Nullable Map<TransferInput<V,S>,IdentityHashMap<Node,TransferResult<V,S>>> analysisCaches)
      Description copied from interface: Analysis
      Runs the analysis again within the block of node and returns the store at the location of node. If before is true, then the store immediately before the Node node is returned. Otherwise, the store immediately after node is returned. If analysisCaches is not null, this method uses a cache. analysisCaches is a map of a block of node to the cached analysis result. If the cache for transferInput is not in analysisCaches, this method creates new cache and stores it in analysisCaches. The cache is a map of nodes to the analysis results of the nodes.
      Specified by:
      runAnalysisFor in interface Analysis<V extends AbstractValue<V>,S extends Store<S>,T extends BackwardTransferFunction<V,S>>
      Parameters:
      node - the node to analyze
      preOrPost - which store to return: the store immediately before node or the store after node
      blockTransferInput - the transfer input of the block of this node
      nodeValues - abstract values of nodes
      analysisCaches - caches of analysis results
      Returns:
      the store before or after node (depends on the value of before) after running the analysis