Package de.fraunhofer.aisec.cpg.passes

Class ControlFlowSensitiveDFGPass.FunctionLevelFixpointIterator

java.lang.Object
de.fraunhofer.aisec.cpg.passes.ControlFlowSensitiveDFGPass.FunctionLevelFixpointIterator
Enclosing class:
ControlFlowSensitiveDFGPass
protected class ControlFlowSensitiveDFGPass.FunctionLevelFixpointIterator
extends java.lang.Object

  • Field Summary

    Fields
    Modifier and Type Field Description
    protected java.util.Map<de.fraunhofer.aisec.cpg.graph.Node,​java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>>> joinPoints  
    protected java.util.Map<de.fraunhofer.aisec.cpg.graph.Node,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> removes
    A Node with refined DFG edges (key) is mapped to a set of nodes that were the previous (unrefined) DFG edges and need to be removed later on

  • Constructor Summary

    Constructors
    Modifier Constructor Description
    protected FunctionLevelFixpointIterator()  

  • Method Summary

    Modifier and Type Method Description
    protected void addDFGToMap​(VariableDeclaration variableDeclaration, de.fraunhofer.aisec.cpg.graph.Node prev, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
    Adds a DFG-Edge to the Mapping of variables.
    protected void addToRemoves​(de.fraunhofer.aisec.cpg.graph.Node curr, de.fraunhofer.aisec.cpg.graph.Node prev)  
    protected java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> createShallowCopy​(java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> state)
    Creates a shallow copy to the depth of the nodes.
    protected java.util.Set<de.fraunhofer.aisec.cpg.graph.Node> eogTraversal​(de.fraunhofer.aisec.cpg.graph.Node node)
    Traverses the EOG starting at a node until there is no more outgoing EOGs to new nodes.
    java.util.Map<de.fraunhofer.aisec.cpg.graph.Node,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> getRemoves()  
    void handle​(de.fraunhofer.aisec.cpg.graph.Node functionRoot)  
    protected de.fraunhofer.aisec.cpg.graph.Node handleDeclaredReferenceExpression​(DeclaredReferenceExpression currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables, ControlFlowSensitiveDFGPass.IterationFunction iterationFunction)
    Method that handles DeclaredReferenceExpressions when the EOG is traversed
    protected java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> iterateTillFixpoint​(de.fraunhofer.aisec.cpg.graph.Node node, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables, de.fraunhofer.aisec.cpg.graph.Node endNode, boolean stopBefore)
    This function collects the set of variable definitions valid for the VariableDeclarations defined in the program when reaching a join-point, a node reached by more than one incoming EOG-Edge.
    protected boolean mergeStates​(java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> currentJoinpoint, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
    Merges two states assuming that both states come from valid paths.
    protected void modifyDFGEdges​(de.fraunhofer.aisec.cpg.graph.Node currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
    Perform the actual modification of the DFG edges based on the values that are recorded in the variables map for every VariableDeclaration
    protected de.fraunhofer.aisec.cpg.graph.Node obtainAssignmentNode​(de.fraunhofer.aisec.cpg.graph.Node node)
    Get node of the BinaryOperator where the assignment is finished (last node of the Assignment)
    protected java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> propagateFromJoinPoints​(de.fraunhofer.aisec.cpg.graph.Node node, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables, de.fraunhofer.aisec.cpg.graph.Node endNode, boolean stopBefore)
    Propagates the state from the join-point until the next join-point is reached.
    protected void propagateValues()
    Iterates over all join-points and propagates the state that is valid for the sum of incoming eog-Paths to refine the dfg edges at variable usage points.
    protected void registerOutgoingDFG​(de.fraunhofer.aisec.cpg.graph.Node currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
    If a Node has a DFG to a VariableDeclaration we need to remove the nextDFG and store the value of the node in our tracking map
    protected void setIngoingDFG​(de.fraunhofer.aisec.cpg.graph.Node currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
    Stores the prevDFG to a VariableDeclaration of a node in the removes map and adds the values of the VariableDeclaration as prevDFGs to the node

    Methods inherited from class java.lang.Object

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

  • Field Details

    • removes

      protected java.util.Map<de.fraunhofer.aisec.cpg.graph.Node,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> removes
      A Node with refined DFG edges (key) is mapped to a set of nodes that were the previous (unrefined) DFG edges and need to be removed later on

    • joinPoints

      protected final java.util.Map<de.fraunhofer.aisec.cpg.graph.Node,​java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>>> joinPoints

  • Constructor Details

    • FunctionLevelFixpointIterator

      protected FunctionLevelFixpointIterator()

  • Method Details

    • handle

      public void handle​(de.fraunhofer.aisec.cpg.graph.Node functionRoot)

    • getRemoves

      public java.util.Map<de.fraunhofer.aisec.cpg.graph.Node,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> getRemoves()

    • addToRemoves

      protected void addToRemoves​(de.fraunhofer.aisec.cpg.graph.Node curr, de.fraunhofer.aisec.cpg.graph.Node prev)

    • eogTraversal

      protected java.util.Set<de.fraunhofer.aisec.cpg.graph.Node> eogTraversal​(de.fraunhofer.aisec.cpg.graph.Node node)
      Traverses the EOG starting at a node until there is no more outgoing EOGs to new nodes.
      Parameters:
      node - starting node
      Returns:
      set containing all nodes that have been reached

    • setIngoingDFG

      protected void setIngoingDFG​(de.fraunhofer.aisec.cpg.graph.Node currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
      Stores the prevDFG to a VariableDeclaration of a node in the removes map and adds the values of the VariableDeclaration as prevDFGs to the node
      Parameters:
      currNode - node that is analyzed

    • registerOutgoingDFG

      protected void registerOutgoingDFG​(de.fraunhofer.aisec.cpg.graph.Node currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
      If a Node has a DFG to a VariableDeclaration we need to remove the nextDFG and store the value of the node in our tracking map
      Parameters:
      currNode - Node that is being analyzed

    • obtainAssignmentNode

      protected de.fraunhofer.aisec.cpg.graph.Node obtainAssignmentNode​(de.fraunhofer.aisec.cpg.graph.Node node)
      Get node of the BinaryOperator where the assignment is finished (last node of the Assignment)
      Parameters:
      node - start node of the assignment LHS DeclaredReferenceExpression
      Returns:
      return the last (in eog order) node of the assignment

    • modifyDFGEdges

      protected void modifyDFGEdges​(de.fraunhofer.aisec.cpg.graph.Node currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
      Perform the actual modification of the DFG edges based on the values that are recorded in the variables map for every VariableDeclaration
      Parameters:
      currNode - node whose dfg edges have to be replaced

    • iterateTillFixpoint

      protected java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> iterateTillFixpoint​(de.fraunhofer.aisec.cpg.graph.Node node, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables, de.fraunhofer.aisec.cpg.graph.Node endNode, boolean stopBefore)
      This function collects the set of variable definitions valid for the VariableDeclarations defined in the program when reaching a join-point, a node reached by more than one incoming EOG-Edge. The state is computed whenever a write access to a variable is encountered. A node may be passed by multiple paths and therefore the states have to be merged at these join-points. However, the number of paths is finite and scales well enough to make a fixpoint iteration of states at join-points is therefore terminating and feasible.

      This function iterates over the entire EOG starting at a fixed node. If the execution of this function is started with the function-Node which also represents the EOG-Root-Node all Nodes that are part of a valid execution path will be traversed.

      Parameters:
      node - - Start of the fixpoint iteration
      variables - - The state, composed of a mapping from variables to expression that were prior written to it.
      endNode - - A node where the iteration shall stop, if null the iteration stops at a point once a fix-point no outgoing eog edge is reached
      stopBefore - - denotes whether the iteration shall stop before or after processing the reached node.
      Returns:
      The state after reaching on of the terminating conditions

    • handleDeclaredReferenceExpression

      protected de.fraunhofer.aisec.cpg.graph.Node handleDeclaredReferenceExpression​(DeclaredReferenceExpression currNode, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables, ControlFlowSensitiveDFGPass.IterationFunction iterationFunction)
      Method that handles DeclaredReferenceExpressions when the EOG is traversed
      Parameters:
      currNode - DeclaredReferenceExpression that is found in
      Returns:
      Node where the EOG traversal should continue

    • propagateValues

      protected void propagateValues()
      Iterates over all join-points and propagates the state that is valid for the sum of incoming eog-Paths to refine the dfg edges at variable usage points.

    • propagateFromJoinPoints

      protected java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> propagateFromJoinPoints​(de.fraunhofer.aisec.cpg.graph.Node node, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables, de.fraunhofer.aisec.cpg.graph.Node endNode, boolean stopBefore)
      Propagates the state from the join-point until the next join-point is reached.
      Parameters:
      node - - Start of the propagation
      variables - - The state, composed of a mapping from variables to expression that were prior written to it collected at some join-point.
      endNode - - A node where the iteration shall stop, if null the iteration stops at a point once a fix-point no outgoing eog edge is reached
      stopBefore - - denotes whether the iteration shall stop before or after processing the reached node.
      Returns:
      The state after reaching on of the terminating conditions

    • addDFGToMap

      protected void addDFGToMap​(VariableDeclaration variableDeclaration, de.fraunhofer.aisec.cpg.graph.Node prev, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
      Adds a DFG-Edge to the Mapping of variables. Updating the state.
      Parameters:
      variableDeclaration - - for which a new valid definition has to be added to the state
      prev - - the defining expression to the variable
      variables - - the state that is updated by the DFG edge

    • mergeStates

      protected boolean mergeStates​(java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> currentJoinpoint, java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> variables)
      Merges two states assuming that both states come from valid paths. All the definition for variables are collected into the current state represented by currentJoinpoint
      Parameters:
      currentJoinpoint - - The state we are merging into
      variables - - The state we are merging from
      Returns:
      whether or not the merging resulted into an update to currentJoinpoint

    • createShallowCopy

      protected java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> createShallowCopy​(java.util.Map<VariableDeclaration,​java.util.Set<de.fraunhofer.aisec.cpg.graph.Node>> state)
      Creates a shallow copy to the depth of the nodes. References to nodes are not copied as new objects. Only the collections are created sd new Objects.
      Parameters:
      state - The state to copy
      Returns:
      The copy