what's the most updated resource for someone approaching writing a compiler plugin for the first time? I saw the from Kevin Most at KotlinConf '18 Then I saw this blog entry, and this with Arrow Meta.. or I could go completely in my own trying to modify and existing plugin what would you suggest me to follow?

Hi, i know kotlin is a null safe language, but jvm has recently (JDK14) added Helpful NPE (for NullPointer exceptions thrown by JVM https://openjdk.java.net/jeps/358) which will describe precisely which variable is null. Can we get the same message in the NPE thrown by kotlin compiler in the following scenario?

hi! I’m trying to develop a plug-in with the new FIR infrastructure, and I have a couple of questions: • in order for the plug-in to work, we need to scrape information from all functions in the CLASSPATH with a certain attribute: is the

FirTypeAttributeExtension

ensured to be run over all possible functions before the next steps in the analysis continue; if not, what is the best way to perform this? • the analysis works in two stages; what is the best way for a FIR plug-in to introduce several stages? thanks very much in advance!

Hi everyone! I have a question regarding type inference of a lamda. Why does compiler infers different type depends of whether a lambda is used as an argument or initialize a variable? Is this the expected behavior? This thing also breaks the inline refactoring making it a changing semantic one.

fun <S> create(code: () -> S): S {
    println("string")
    return code()
}

fun create(code: () -> Unit) {
    println("unit")
}

fun main() {
    create { "a" } // prints unit
    val a = { "a" }
    create(a) // prints string
}

is there any way to have the compiler dump IR from the CLI or API? i think a great addition to the Kotlin support on godbolt would be the IR output in addition to Java bytecode

Hi, I'm writing (trying) a kotlin compiler plugin, which uses the IrGenerationExtension. I am trying to access dependencies of the module, and to iterate the declarations (Classes, etc) in each depended on module. How should I do this? I tried `

moduleFragment.descriptor.allDependencyModules

but it does not seem to give me the depended on modules? I also tried `

(pluginContext.symbolTable as SymbolTable).forEachPublicSymbol {

but I only get the symbols from the current module. some pointers in the right direction for either of these would be great, thanks

hi! what is the status of using a FIR plugin? we are doing some investigation, and would like to know how to specify that we want to use our plug-in in the build, and in the IDE 🙏

Did i understand the k2 talk from today correctly in that if we are explicit with our return types we can expect a potential performance boost in compilation in the future?

I wonder if this is the right place, however I'm feeding

kotlinc

this way (via gradle

project.exe

):

[C:\Users\elect\IdeaProjects\lwjgl3\bin2\libs\kotlinc\bin\kotlinc.bat, -d, C:\Users\elect\IdeaProjects\lwjgl3\bin2\classes\generator, -jvm-target, 1.8, -module-name, generator, -progressive, -version, -Xlambdas=indy, -Xno-call-assertions, -Xno-param-assertions, -Xreport-perf, C:\Users\elect\IdeaProjects\lwjgl3\modules\generator\src\main\kotlin]

And I see on the output:

info: kotlinc-jvm 1.5.31 (JRE 11.0.9.1+1-LTS)

warning: advanced option value is passed in an obsolete form. Please use the '=' character to specify the value: -Xlambdas=...

Which is weird, because I'm actually using that form.. This is on Windows though, on Linux no issues..

Hello everyone, I’m a novice at kotlin compiler. I’m trying to write a compiler plugin. I want to change the

val

of property to

var

in

IrElementTransformerVoid.visitPropertyNew

, but I found that

isVar

is a immutable value. What should I do?

How should I return multi expressions in

IrGenerationExtension.visitCall

?

❓ I have been working on a gradle plugin to support including IR plugins in gradle submodules for a project, without requiring separate gradle plugins. Similar to what KSP does, but for arbitrary IR plugins. It is working already, but I have not published it to central yet. Do you know if there is anything already for that or some efforts in that direction, to avoid doing it twice?

Maybe someone knows before I file a ticket. I have a compiler plugin that currently supports the IR and old backend. It uses

IrGenerationExtension

for the IR implementation and

ExpressionCodegenExtension

. When KAPT is enabled in the stub generating task I see the

ExpressionCodegenExtension

being called rather than the IR implementation. Is the stub generating task not using the IR backend and still relies on the old backend? I’ve tested with

1.5.31

and

1.6.0-RC2

.

was there ever a discussion about trying to avoid autoboxing in the case where you have a data type like

public class DoubleArrayList(): AbstractList<Double> {
  public operator fun get(index: Int): Double //I want the signature (I)D. 
  // I do NOT want the signature (I)Ljava/lang/Double;
}

? I cant help but feel like with all the sophistication of inline classes, kotlins type unification and etc, I could finally have a

List<Double>

that doesnt do an enormous amount of boxing/unboxing. Like, why not generate a function

get()

that's

(I)Lj/l/Double;

and a function

get_$D()

that's

(I)D

, and where the compiler can be certain ahead of time that we're calling DoubleArrayList's

get

, it generates code for`get_$D` instead of

get()

? Again, I know theres a good reason, im just curious. I'm doing some profiling of my app right now, which itself delegates most work to some (fairly recent) fortran code, but it does have some hot loops on the VM, and most are related to poor performance of

Map<String, Double>

and

List<Double>

Some of those are architectural but, it would be nice if i could flip a kind of switch to say "stop using

Double[]

as your backing data types and start using

double[]

" to see how that helps performance

Hello everyone, a noob about compiler plugins here. Please, I have question: Is it possible to write a compiler plugin that targets a language or platform not officially supported by the Kotlin compiler? If so, how does one start? Thanks.

Hi, I’m writing a simple compiler plugin to do slight modifications in the generated code for our JS target. I’m invoking the

compileProductionLibraryKotlinJs

task and it seems JS gets compiled twice - once into a klib where the compiler plugin is called correctly and later into a JS library where the compiler plugin is not invoked at all. This means that my changes are visible in the klib but not in the resulting JS library code. Is this an expected behavior? Can I get the IR plugin to execute every time a JS compilation is running? It also seems inefficient to run it twice (I don’t necessarily need the klib...). I’m on Kotlin 1.5.31, Gradle 7.2. My Gradle configuration:

js(IR) {
    moduleName = "facemoji-core"
    browser {
        webpackTask {
            output.libraryTarget = "commonjs-module"
        }
    }
    binaries.library()

    compilations.all {
        kotlinOptions {
            freeCompilerArgs = freeCompilerArgs + "-Xopt-in=kotlin.ExperimentalStdlibApi -Xopt-in=kotlin.RequiresOptIn"
        }
    }
}

Hello, I’d link to build a replacement to

android-kotlin-extensions

! I love it and I don’t want to use

ViewBinding

as we have lots and lots of layout and running its annotation processor is making the project quite unstable. So the question is, where do I start for the core of its functionality, meaning adding a Hashmap to any class that uses it, and call

findViewById

on the first use of a property? 😄

Hi, does anyone know how to obtain a

ModuleDescriptor

from a

KtFile

in version 1.5.0 of the

kotlin-compiler-embeddable

? I'm working on a compiler plugin, and using some utilities from forge that require a

ModuleDescriptor

in their API, but I can't figure out how to properly construct one from a

KtFile

.

Hi, why is a SAM implementation producing different compiler outputs depending on if object or lambda style notation are being used?

fun interface SmthgSAMGeneric<T> {
    fun foo(): (T, T) -> String
}

 val samAsObject = object : SmthgSAMGeneric<String> {
        override fun foo(): (String, String) -> String {
            return { s: String, s2: String -> "42" }
        }
    }

val inlineSam = SmthgSAMGeneric<String> {
    { s: String, s2: String -> "42" }
}

See also https://github.com/EsotericSoftware/kryo/issues/867

Was

KType.javaType

intentionally left out of the 1.6 API promotions to stable or an oversight? Seems surprising to see that not included with the

typeOf()

promotions Edit: filed a request here in case it helps https://youtrack.jetbrains.com/issue/KT-49743

Not sure where to start. Let me know if this is a known issue and if I should just file a bug.

Hi folks, is there a way to get furthest parent KtClassOrObject from KtClassOrObject?

Hi, are there instructions on how to compile the embeddable version of the compiler? I would like to experiment with some stuffs and run it on an android environment.

I'm trying to compile and test the kotlin compiler, but I alsways get plenty of tests failing after a while with StackOverflowErrors, I'm guessing it is a memory exhaustion problem but I don't know how to overcome it. I tried running the tests in sequential mode with things like:

org.gradle.workers.max=1
kotlin.test.junit5.maxParallelForks=1
kotlin.parallel.tasks.in.project=false
org.gradle.parallel=false

in my gradle.properfies file, but it just made the tests much slower and the same errors appeared. The command I am running is:

./gradlew -Porg.gradle.java.installations.auto-detect=false compilerTest

. Maybe it's too wide a task, but how to refine it? Especially, how would I specifically test tweaks to the lexer and the parser? Thanks for your help.

Just hit this again, this time trying to do this:

typealias Result<F : Throwable, S> = Either<F, S>

Still curious what the reason for

Bounds are not allowed on type alias parameters

is.

I saw parcelize has a new commit of FIR. I still don’t quite understand the difference between FIR and IR. Who can solve my doubts? In addition, does the plugin implemented with Fir need to open

useFir

in Gradle before it can be used?

been doing some kotlin 1.6.0 compilation profiling and it's not looking good. Anyone else seeing similar? incremental abi change in a library and app and incremental build • 39s before, 58s after incremental change in just a feature project • 36s before, 55s after

What is 'EE' as in '[EE-IR] Support Inline functions'?

Can I get a warning on unused

@OptIn(SomeExperimentalApi::class)

usages? It's quite easy to leave them cluttering the codebase after the declarations have been promoted to stable (or something else is used).

I am using the embeddable Kotlin compiler to analyze code and obtain the

BindingContext

. Now this takes quite a while and I know the compiler is doing a lot of work in that time. Is it possible to run the compiler multi-threaded, so that I can make use of multiple cores when available and hence speed up the analysis?