Hi! I've been poking around `IrGenerationExtension...

# compiler

[Shannon Yang]

Hi! I've been poking around IrGenerationExtension, and am trying to add a function to annotated classes that just prints "Hello World". I got stuck figuring out how to find the println descriptor or symbol to build the function call through IrCallImpl. Does anyone know where I could find an example, or another way I could go about this? Thanks!

[raulraja]

Not sure if relevant but you may find some of these functions that go from descriptors to IR useful https://github.com/47deg/arrow-meta-prototype/blob/rr-idea-improvements/compiler-plugin/src/main/kotlin/arrow/meta/ir/IrUtils.kt

[raulraja]

That is if you can get a hold of any descriptor by name you can get the Ir with one of those function or similar way. Maybe there is a better way but this is what I came up reading the compiler sources

[Shannon Yang]

Thanks for sending that, Raul. definitely helps as a reference for getting the call. 😄 Do you know how to get a descriptor by name?

[Shannon Yang]

Updating with possible leads in DescriptorUtils, haven't gotten anything working yet though: https://github.com/facebookincubator/differentiable-kotlin/blob/7ff01b02a98a815fa32df4fed2d24fb1a172545a/core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java#L602

[raulraja]

I think you may be able to get a hold of it via a ClassId or something like:

module.getPackageByName("<http://kotlin.io|kotlin.io>").getContributedDescriptors(name, filter)

[raulraja]

or something like that if I recall, sorry not near the sources now

[raulraja]

also you can always type it in a string use the KtPsiFactory to parse it then feed it to the analysis to get an AnalysisResult and ask it in the binding trace for the resulting descriptor

[raulraja]

But that implies you are attempting to do half of the compilation manually and I’m sure if what you want is just get println as a descriptor there is some other way to do that.

[raulraja]

There is also a slice in the Binding Context that is called FQNAME_TO_CLASS_DESCRIPTOR but I’m not sure if it holds references to external symbols or just the local ones in the module being compiled

[Shannon Yang]

That seems to do it. Thanks, @raulraja!

[Dominaezzz]

What seems do do it? I happen to be doing the exact same thing, of trying to look up IrFunctionSymbol based on a some name.

[Dominaezzz]

Nvm, I found some other way.

[andylamax]

Is there some kind of repo for this? I am trying to do this "Hello World" thing as well