Class ControlFlow


  • public class ControlFlow
    extends java.lang.Object
    Represents the control flow graph of a given method.

    To obtain the control flow graph, do the following:

    CtMethod m = ...
     ControlFlow cf = new ControlFlow(m);
     Block[] blocks = cf.basicBlocks();
     

    blocks is an array of basic blocks in that method body.

    Since:
    3.16
    Author:
    Shigeru Chiba
    See Also:
    CtMethod, ControlFlow.Block, Frame, Analyzer
    • Method Summary

      Modifier and Type Method Description
      ControlFlow.Block[] basicBlocks()
      Returns all the basic blocks in the method body.
      ControlFlow.Node[] dominatorTree()
      Constructs a dominator tree.
      Frame frameAt​(int pos)
      Returns the types of the local variables and stack frame entries available at the given position.
      ControlFlow.Node[] postDominatorTree()
      Constructs a post dominator tree.
      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Method Detail

      • basicBlocks

        public ControlFlow.Block[] basicBlocks()
        Returns all the basic blocks in the method body.
        Returns:
        an array of basic blocks, the array has length 0 if the method doesn't have code.
      • frameAt

        public Frame frameAt​(int pos)
                      throws BadBytecode
        Returns the types of the local variables and stack frame entries available at the given position. If the byte at the position is not the first byte of an instruction, then this method returns null.
        Parameters:
        pos - the position.
        Throws:
        BadBytecode
      • dominatorTree

        public ControlFlow.Node[] dominatorTree()
        Constructs a dominator tree. This method returns an array of the tree nodes. The first element of the array is the root of the tree.

        The order of the elements is the same as that of the elements in the Block array returned by the basicBlocks method. If a Block object is at the i-th position in the Block array, then the Node object referring to that Block object is at the i-th position in the array returned by this method. For every array element node, its index in the array is equivalent to node.block().index().

        Returns:
        an array of the tree nodes, or null if the method doesn't have code.
        See Also:
        ControlFlow.Node.block(), ControlFlow.Block.index()
      • postDominatorTree

        public ControlFlow.Node[] postDominatorTree()
        Constructs a post dominator tree. This method returns an array of the tree nodes. Note that the tree has multiple roots. The parent of the root nodes is null.

        The order of the elements is the same as that of the elements in the Block array returned by the basicBlocks method. If a Block object is at the i-th position in the Block array, then the Node object referring to that Block object is at the i-th position in the array returned by this method. For every array element node, its index in the array is equivalent to node.block().index().

        Returns:
        an array of the tree nodes, or null if the method doesn't have code.
        See Also:
        ControlFlow.Node.block(), ControlFlow.Block.index()