Hello, I've written a compiler plugin for the new ...

# compiler

[FalseHonesty]

Hello, I've written a compiler plugin for the new 1.4.0 IR compiler backend, and I am now using it in a project of mine. I want to see the bytecode output, and to do so I am using the IntelliJ "Kotlin Bytecode Viewer" built-in tool. In that tool, there is a checkbox for using IR, so I enabled it, but it caused this error when trying to display the bytecode: java.lang.IllegalStateException: No module deserializer found for <library Gradle: net.minecraft:minecraftSrc:1.12.2> is a module[ModuleDescriptorImpl@5c013a11]. I'm not sure what this means?

[udalov]

I’m also not sure what it means, but we basically do not guarantee anything about the Kotlin Bytecode toolwindow, and it might not even work sometimes at all. I recommend you to use javap (probably with -v for verbose) instead. It’s not as convenient, but is pretty fast if you’re used to it and it’s guaranteed to work

[FalseHonesty]

Oh okay, thank you. By the way, is there a way for me to check to make sure the compiler is even using the IR backend (I'm using Gradle)?

[FalseHonesty]

I have what I believe is the correct configuration, but my plugin doesn't seem to be doing anything.

[udalov]

The most fireproof method is to check the value of the flag xi in the kotlin.Metadata annotation on the class file. Using javap -v Some.class, you can see this at the end:

RuntimeVisibleAnnotations:
  0: #25(#26=[I#27,I#28,I#27],#29=[I#27,I#30,I#31],#32=I#33,#34=I#35,#36=[s#37],#38=[s#5,s#39,s#23,s#39])
    kotlin.Metadata(
      mv=[1,4,1]
      bv=[1,0,3]
      k=2
      xi=16
      d1=[...]
      d2=[...]
    )

If the value of xi & 16 is not zero, then the class file is compiled using the IR backend :). For example, 16 means that it is.
(As per https://github.com/JetBrains/kotlin/blob/master/libraries/stdlib/jvm/runtime/kotlin/Metadata.kt#L71)