Package ghidra.pcode.emu.jit.analysis

Class JitControlFlowModel.JitBlock

java.lang.Object
ghidra.pcode.exec.PcodeProgram
ghidra.pcode.emu.jit.analysis.JitControlFlowModel.JitBlock
Enclosing class:
JitControlFlowModel
public static class JitControlFlowModel.JitBlock extends PcodeProgram
A basic block of p-code

This follows the formal definition of a basic block, but at the p-code level. All flows into the block enter at its first op, and all flows out of the block exit at its last op. The block also contains information about these flows as well as branches out of the passage via this block.

  • Constructor Details

    • JitBlock

      public JitBlock(PcodeProgram program, List<PcodeOp> code)
      Construct a new block
      Parameters:
      program - the program (i.e., passage) from which this block is derived
      code - the subset of ops, in execution order, comprising this block

  • Method Details

    • getHead

      protected String getHead()
      Description copied from class: PcodeProgram
      For display purposes, get the header above the frame, usually the class name
      Overrides:
      getHead in class PcodeProgram
      Returns:
      the frame's display header

    • toString

      public String toString()
      Overrides:
      toString in class PcodeProgram

    • first

      public PcodeOp first()
      Get the first p-code op in this block
      Returns:
      the first p-code op

    • start

      public SequenceNumber start()
      Get the sequence number of the first op

      This is used for display and testing purposes only.

      Returns:
      the sequence number

    • end

      public SequenceNumber end()
      Get the sequence number of the last op

      This is used for display and testing purposes only.

      Returns:
      the sequence number

    • flowsFrom

      public Map<JitPassage.IntBranch,JitControlFlowModel.BlockFlow> flowsFrom()
      Get (internal) flows leaving this block
      Returns:
      the flows, keyed by branch

    • flowsTo

      public Map<JitPassage.IntBranch,JitControlFlowModel.BlockFlow> flowsTo()
      Get (internal) flows entering this block
      Returns:
      the flows, keyed by branch

    • branchesFrom

      public List<JitPassage.IntBranch> branchesFrom()
      Get internal branches leaving this block
      Returns:
      the list of branches

    • branchesTo

      public List<JitPassage.IntBranch> branchesTo()
      Get internal branches entering this block
      Returns:
      the list of branches

    • branchesOut

      public List<JitPassage.Branch> branchesOut()
      Get branches leaving the passage from this block
      Returns:
      the list of branches

    • getFallFrom

      public JitControlFlowModel.JitBlock getFallFrom()
      If this block has fall through, find the block into which it falls
      Returns:
      the block, or null

    • hasJumpTo

      public boolean hasJumpTo()
      Check if there is an internal non-fall-through branch to this block

      This is used by the JitCodeGenerator to determine whether or not a block's bytecode needs to be labeled.

      Returns:
      true if this block is targeted by a branch

    • getTargetBlock

      public JitControlFlowModel.JitBlock getTargetBlock(JitPassage.IntBranch branch)
      Get the target block for the given internal branch, assuming it's from this block
      Parameters:
      branch - the branch
      Returns:
      the target block or null

    • instructionCount

      public int instructionCount()
      Get the number of instructions represented in this block

      This may get dicey as blocks are not necessarily split on instruction boundaries. Nevertheless, we seek to count the number of instructions executed at runtime, so that we can replay an execution, step in reverse, etc. What we actually do here is count the number of ops which are the first op produced by a decoded instruction.

      Returns:
      the instruction count
      See Also:

    • trailingOpCount

      public int trailingOpCount()
      Get the number of trailing ops in this block

      It is possible a block represents only partial execution of an instruction. Though instructionCount() will count this partial instruction, we can tell how far we got into it by examining this value. With this, we should be able to replay an execution to exactly the same p-code op step.

      Returns:
      the trailing op count