Scala 3 inlining phase profile compiler plugin

build.sbt

// NIGHTLY require for ResearchPlugin
// https://github.com/lampepfl/dotty/blob/ed9267e8e1af6472db2b9164d92668de5b61376f/compiler/src/dotty/tools/dotc/plugins/Plugins.scala#L129-L133
scalaVersion := "3.1.3-RC1-bin-20220328-ed9267e-NIGHTLY"

organization := "com.github.xuwei-k"

name := "inlining-profile"

libraryDependencies += "org.scala-lang" %% "scala3-compiler" % scalaVersion.value

version := "0.1.0-SNAPSHOT"

InliningProfile.scala

package example

import dotty.tools.dotc.CompilationUnit
import dotty.tools.dotc.core.Contexts.Context
import dotty.tools.dotc.core.Phases.Phase
import dotty.tools.dotc.plugins.ResearchPlugin
import dotty.tools.dotc.transform.Inlining

class InliningProfile extends ResearchPlugin {
  override val name: String = "my-inlining"
  override val description: String = "my inlining plugin"

  def init(options: List[String], phasesList: List[List[Phase]])(implicit ctx: Context): List[List[Phase]] = {
    phasesList.map {
      _.map {
        case phase if phase.phaseName == "inlining" =>
          println("replace inlining phase")
          new MyInliningPhase()
        case other =>
          other
      }
    }
  }
}

class MyInliningPhase extends Inlining {
  private[this] val compileTimeResults = scala.collection.concurrent.TrieMap.empty[String, Long]

  override def runOn(units: List[CompilationUnit])(using Context): List[CompilationUnit] = {
    println("start inlining")
    val result = super.runOn(units)
    println("end inlining")
    compileTimeResults.toList.sortBy(-_._2).take(50).foreach(println)
    result
  }
  override def run(using c: Context): Unit = {
    val start = System.currentTimeMillis()
    super.run
    val end = System.currentTimeMillis()
    compileTimeResults += (c.compilationUnit.source.path -> (end - start))
  }
}

plugin.properties

pluginClass=example.InliningProfile

usage-setting-example.sbt

scalaVersion := "3.1.3-RC1-bin-20220328-ed9267e-NIGHTLY"

addCompilerPlugin("com.github.xuwei-k" %% "inlining-profile" % "0.1.0-SNAPSHOT")