How to generate control flow graph from Scala code?

Question

I want to see the control flow graph generated by the Scala compiler. Is there a way to do so? I tried searching online but only found Eclipse plugins for Java like the one from here www.drgarbage.com but none for Scala.

Thanks

EDIT: I took the .class file generated by scalac and opened that with the dr garbage plug in to see the bytecode visualized as a control flow graph. But scalac makes 3 different .class files: Foo, Foo$, and Foo$delayedInit$body. I see a bunch of disconnected graphs and only one of the graphs in Foo$ looks reasonable. I tried searching online for the difference between the 3 .class files but couldn't find anything.

I believe `Foo` is your class, `Foo$` is the companion object, but I'm not sure about the last one. — Daenyth, Jun 02 '15 at 01:46

score 0 · Accepted Answer · answered Jul 05 '15 at 02:53

0

I didn't realize that the IR (intermediate representation) for scala in the backend was actually called icode. The option in the compiler -Xprint-icode actually shows the IR separated into basic blocks. This was what I was looking for.

answered Jul 05 '15 at 02:53

Lotus Fenn

85
7

This feature might be removed as of scala 2.12 - [see here](http://www.scala-lang.org/news/2.12.0-M2). A better approach might be a compiler plugin. – matanster Nov 18 '15 at 09:25

score 0 · Answer 2 · answered Nov 18 '15 at 09:37

A compiler plugin can do just that. However, it requires abstracting away some internals introduced by the compiler - which are more specific than what you'd expect from how a project's source code looks. You can use this plugin to get the raw information extracted for you, whereas the re-abstraction from the raw data is still work-in-progress, and you'd have to sbt publishLocal before you can include this plugin in your sbt definition.

How to generate control flow graph from Scala code?

2 Answers2