Package de.fraunhofer.aisec.cpg.passes

Class EvaluationOrderGraphPass

java.lang.Object
de.fraunhofer.aisec.cpg.passes.Pass
de.fraunhofer.aisec.cpg.passes.EvaluationOrderGraphPass
All Implemented Interfaces:
java.util.function.Consumer<TranslationResult>
public class EvaluationOrderGraphPass
extends Pass
Creates an Evaluation Order Graph (EOG) based on AST.

An EOG is an intraprocedural directed graph whose vertices are executable AST nodes and edges connect them in the order they would be executed when running the program.

An EOG always starts at the header of a method/function and ends in one (virtual) or multiple return statements. A virtual return statement with a code location of (-1,-1) is used if the actual source code does not have an explicit return statement.

The EOG is similar to the CFG ControlFlowGraphPass, but there are some subtle differences:

  • For methods without explicit return statement, EOF will have an edge to a virtual return node with line number -1 which does not exist in the original code. A CFG will always end with the last reachable statement(s) and not insert any virtual return statements.
  • EOG considers an opening blocking ("CompoundStatement", indicated by a "{") as a separate node. A CFG will rather use the first actual executable statement within the block.
  • For IF statements, EOG treats the "if" keyword and the condition as separate nodes. CFG treats this as one "if" statement.
  • EOG considers a method header as a node. CFG will consider the first executable statement of the methods as a node.

  • Field Summary

    Fields
    Modifier and Type Field Description
    protected java.util.Map<java.lang.Class<? extends de.fraunhofer.aisec.cpg.graph.Node>,​CallableInterface<? extends de.fraunhofer.aisec.cpg.graph.Node>> map  

    Fields inherited from class de.fraunhofer.aisec.cpg.passes.Pass

    lang, log

  • Constructor Summary

    Constructors
    Constructor Description
    EvaluationOrderGraphPass()  

  • Method Summary

    Modifier and Type Method Description
    void accept​(TranslationResult result)  
    void addEOGEdge​(de.fraunhofer.aisec.cpg.graph.Node prev, de.fraunhofer.aisec.cpg.graph.Node next)
    Builds an EOG edge from prev to next.
    void addMultipleIncomingEOGEdges​(java.util.List<de.fraunhofer.aisec.cpg.graph.Node> prevs, de.fraunhofer.aisec.cpg.graph.Node next)  
    void addToCurrentEOG​(java.util.List<de.fraunhofer.aisec.cpg.graph.Node> nodes)  
    static boolean checkEOGInvariant​(de.fraunhofer.aisec.cpg.graph.Node n)
    Checks if every node that has another node in its next or previous EOG List is also contained in that nodes previous or next EOG list to ensure the bidirectionality of the relation in both lists.
    void cleanup()  
    void connectCurrentToLoopStart()
    Connects current EOG nodes to the previously saved loop start to mimic control flow of loops
    void createEOG​(@Nullable de.fraunhofer.aisec.cpg.graph.Node node)  
    void exitLoop​(@NonNull Statement loopStatement, @NonNull LoopScope loopScope)
    Connects the current EOG leaf nodes to the last stacked node, e.g.
    java.util.List<de.fraunhofer.aisec.cpg.graph.Node> getCurrentEOG()  
    void pushToEOG​(@NonNull de.fraunhofer.aisec.cpg.graph.Node node)
    Creates an EOG-edge between the given argument node and the saved currentEOG Edges.
    void setCurrentEOG​(de.fraunhofer.aisec.cpg.graph.Node node)  
    void setCurrentEOG​(java.util.List<de.fraunhofer.aisec.cpg.graph.Node> currentEOG)  
    <T extends de.fraunhofer.aisec.cpg.graph.Node>
    void    		 setCurrentEOGs​(java.util.List<T> nodes)  

    Methods inherited from class de.fraunhofer.aisec.cpg.passes.Pass

    getLang, setLang, supportsLanguageFrontend

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface java.util.function.Consumer

    andThen

  • Field Details

    • map

      protected final java.util.Map<java.lang.Class<? extends de.fraunhofer.aisec.cpg.graph.Node>,​CallableInterface<? extends de.fraunhofer.aisec.cpg.graph.Node>> map

  • Constructor Details

    • EvaluationOrderGraphPass

      public EvaluationOrderGraphPass()

  • Method Details

    • cleanup

      public void cleanup()
      Specified by:
      cleanup in class Pass

    • accept

      public void accept​(TranslationResult result)

    • checkEOGInvariant

      public static boolean checkEOGInvariant​(de.fraunhofer.aisec.cpg.graph.Node n)
      Checks if every node that has another node in its next or previous EOG List is also contained in that nodes previous or next EOG list to ensure the bidirectionality of the relation in both lists.
      Parameters:
      n -
      Returns:

    • createEOG

      public void createEOG​(@Nullable de.fraunhofer.aisec.cpg.graph.Node node)

    • pushToEOG

      public void pushToEOG​(@NonNull de.fraunhofer.aisec.cpg.graph.Node node)
      Creates an EOG-edge between the given argument node and the saved currentEOG Edges.
      Parameters:
      node - node that gets the incoming edge

    • getCurrentEOG

      public java.util.List<de.fraunhofer.aisec.cpg.graph.Node> getCurrentEOG()

    • setCurrentEOG

      public void setCurrentEOG​(java.util.List<de.fraunhofer.aisec.cpg.graph.Node> currentEOG)

    • setCurrentEOG

      public void setCurrentEOG​(de.fraunhofer.aisec.cpg.graph.Node node)

    • setCurrentEOGs

      public <T extends de.fraunhofer.aisec.cpg.graph.Node> void setCurrentEOGs​(java.util.List<T> nodes)

    • addToCurrentEOG

      public void addToCurrentEOG​(java.util.List<de.fraunhofer.aisec.cpg.graph.Node> nodes)

    • exitLoop

      public void exitLoop​(@NonNull Statement loopStatement, @NonNull LoopScope loopScope)
      Connects the current EOG leaf nodes to the last stacked node, e.g. loop head, and removes the nodes.
      Parameters:
      loopStatement - the loop statement
      loopScope - the loop scope

    • connectCurrentToLoopStart

      public void connectCurrentToLoopStart()
      Connects current EOG nodes to the previously saved loop start to mimic control flow of loops

    • addEOGEdge

      public void addEOGEdge​(de.fraunhofer.aisec.cpg.graph.Node prev, de.fraunhofer.aisec.cpg.graph.Node next)
      Builds an EOG edge from prev to next. 'eogDirection' defines how the node instances save the references constituting the edge. 'FORWARD': only the nodes nextEOG member contains references, an points to the next nodes. 'BACKWARD': only the nodes prevEOG member contains references and points to the previous nodes. 'BIDIRECTIONAL': nextEOG and prevEOG contain references and point to the previous and the next nodes.
      Parameters:
      prev - the previous node
      next - the next node

    • addMultipleIncomingEOGEdges

      public void addMultipleIncomingEOGEdges​(java.util.List<de.fraunhofer.aisec.cpg.graph.Node> prevs, de.fraunhofer.aisec.cpg.graph.Node next)