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Visualize IonMonkey CFGs using GraphViz.

branch: master
  Primitive visualizer for IonMonkey graphs using GraphViz.
  Doesn't involve Java. Generated images and DOT files are saved on disk.

  Copyright Sean Stangl <>, 2011-2012.


  IonMonkey is a compiler for JavaScript that uses an SSA-form IR.

  Mozilla-Central ( includes IonMonkey
  as part of the SpiderMonkey JavaScript engine in js/src.


  Make a debug build of IonMonkey, then run with the envvar IONFLAGS=logs.
  IonMonkey will then dump observations about graph state into /tmp/ion.json.

  Executing 'make' reads in this file, outputs a DOT file for each function
  and for each pass for each function, and then generates visualizations
  of those DOT files in PNG and PDF format.

  Iterating over those files crudely shows changes to the graph over time.


  Blocks with green borders are loop headers.
  Blocks with red borders contain loop backedges (successor is a header).
  Blocks with dashed borders were created during critical edge splitting.

  Instructions that are movable are blue.
  Instructions that cannot be hoisted even if movable are underlined.

  MResumePoints are placed as instructions, colored gray.

  Edges from blocks ending with conditional branches are annotated with
    the truth value associated with each edge, given as '0' or '1'.

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