improvement: Better source positions relativization

nir/src/main/scala/scala/scalanative/nir/Position.scala

@@ -45,12 +45,12 @@ object Position {
 sealed trait SourceFile {
   def filename: Option[String] = this match {
     case SourceFile.Virtual => None
-    case source: SourceFile.SourceRootRelative =>
+    case source: SourceFile.Relative =>
       Option(source.path.getFileName()).map(_.toString())
   }
   def directory: Option[String] = this match {
     case SourceFile.Virtual => None
-    case source: SourceFile.SourceRootRelative =>
+    case source: SourceFile.Relative =>
       Option(source.path.getParent()).map(_.toString())
   }
 }
@@ -65,7 +65,7 @@ object SourceFile {
    *    path relative to `-sourceroot` setting defined when compiling source -
    *    typically it's root directory of workspace
    */
-  case class SourceRootRelative(pathString: String) extends SourceFile {
+  case class Relative(pathString: String) extends SourceFile {
     lazy val path: Path = Paths.get(pathString)
   }
 }

nir/src/main/scala/scala/scalanative/nir/serialization/BinaryDeserializer.scala

@@ -489,7 +489,7 @@ final class BinaryDeserializer(buffer: ByteBuffer, nirSource: NIRSource) {
   def getPosition(): nir.Position = in(prelude.sections.positions) {
     val file = getString() match {
       case ""   => nir.SourceFile.Virtual
-      case path => nir.SourceFile.SourceRootRelative(path)
+      case path => nir.SourceFile.Relative(path)
     }
     val line = getLebUnsignedInt()
     val column = getLebUnsignedInt()

nir/src/main/scala/scala/scalanative/nir/serialization/BinarySerializer.scala

@@ -81,8 +81,8 @@ final class BinarySerializer(channel: WritableByteChannel) {
     override def put(pos: nir.Position): Unit = {
       putString {
         pos.source match { // interned
-          case nir.SourceFile.Virtual                        => ""
-          case nir.SourceFile.SourceRootRelative(pathString) => pathString
+          case nir.SourceFile.Virtual              => ""
+          case nir.SourceFile.Relative(pathString) => pathString
         }
       }
       putLebUnsignedInt(pos.line)

nscplugin/src/main/scala-2/scala/scalanative/nscplugin/NirGenPhase.scala

@@ -1,7 +1,7 @@
 package scala.scalanative
 package nscplugin
 
-import java.nio.file.{Path => JPath}
+import java.nio.file.{Path => JPath, Paths => JPaths}
 import java.util.stream.{Stream => JStream}
 import java.util.function.{Consumer => JConsumer}
 import scala.collection.mutable
@@ -206,15 +206,14 @@ abstract class NirGenPhase[G <: Global with Singleton](override val global: G)
      *  It returns the absolute path of `source` if it is not contained in
      *  `reference`.
      */
-    def relativePath(source: CompilerSourceFile, reference: String): String = {
+    def relativePath(source: CompilerSourceFile, reference: JPath): String = {
       val file = source.file
       val jfile = file.file
       if (jfile eq null)
         file.path // repl and other custom tests use abstract files with no path
       else {
         val sourcePath = jfile.toPath.toAbsolutePath.normalize
-        val refPath =
-          java.nio.file.Paths.get(reference).toAbsolutePath.normalize
+        val refPath = reference.normalize
         if (sourcePath.startsWith(refPath)) {
           val path = refPath.relativize(sourcePath)
           import scala.collection.JavaConverters._
@@ -223,20 +222,26 @@ abstract class NirGenPhase[G <: Global with Singleton](override val global: G)
       }
     }
 
-    private val sourceRoot: String = {
-      val sourcePath = settings.sourcepath.value
-      if (sourcePath.isEmpty) settings.rootdir.value
-      else sourcePath
-    }
+    private val sourceRoot = JPaths
+      .get {
+        val sourcePath = settings.sourcepath.value
+        if (sourcePath.isEmpty) settings.rootdir.value
+        else sourcePath
+      }
+      .toAbsolutePath()
+
     private[this] def convert(
         nscSource: CompilerSourceFile
     ): nir.SourceFile = {
       if (nscSource.file.isVirtual) nir.SourceFile.Virtual
       else {
-        val sourceRelativePath = relativePath(nscSource, sourceRoot)
-        nir.SourceFile.SourceRootRelative(sourceRelativePath)
+        val absSourcePath = nscSource.file.absolute.file.toPath()
+        val relativeTo = scalaNativeOpts.positionRelativizationPaths
+          .find(absSourcePath.startsWith(_))
+          .map(_.toAbsolutePath())
+          .getOrElse(sourceRoot)
+        nir.SourceFile.Relative(relativePath(nscSource, relativeTo))
       }
-
     }
   }
 }

nscplugin/src/main/scala-2/scala/scalanative/nscplugin/NirGenStat.scala

@@ -486,11 +486,11 @@ trait NirGenStat[G <: nsc.Global with Singleton] { self: NirGenPhase[G] =>
         // initialising and returning an instance of the class, using C.
         for ((ctor, ctorIdx) <- ctors.zipWithIndex) {
           val ctorSig = genMethodSig(ctor)
-          val ctorArgsSig = ctorSig.args.map(_.mangle).mkString
+          val ctorSuffix = if (ctorIdx == 0) "" else s"$$$ctorIdx"
           implicit val pos: nir.Position = ctor.pos
 
           reflectiveInstantiationInfo += ReflectiveInstantiationBuffer(
-            fqSymId + ctorArgsSig
+            fqSymId + ctorSuffix
           )
           val reflInstBuffer = reflectiveInstantiationInfo.last
 

nscplugin/src/main/scala-2/scala/scalanative/nscplugin/ScalaNativeOptions.scala

@@ -1,6 +1,6 @@
 package scala.scalanative.nscplugin
 
-import java.net.URI
+import java.nio.file.Path
 
 /** This trait allows to query all options to the ScalaNative Plugin
  *
@@ -16,4 +16,7 @@ trait ScalaNativeOptions {
    *  of JDK classes.
    */
   def genStaticForwardersForNonTopLevelObjects: Boolean
+
+  /** List of paths usd for relativization of source file positions */
+  def positionRelativizationPaths: Seq[Path]
 }

nscplugin/src/main/scala-2/scala/scalanative/nscplugin/ScalaNativePlugin.scala

@@ -3,8 +3,7 @@ package nscplugin
 
 import scala.tools.nsc._
 import scala.tools.nsc.plugins._
-import java.net.URI
-import java.net.URISyntaxException
+import java.nio.file.{Path, Paths}
 
 class ScalaNativePlugin(val global: Global) extends Plugin {
   val name = "scalanative"
@@ -25,6 +24,8 @@ class ScalaNativePlugin(val global: Global) extends Plugin {
 
   object scalaNativeOpts extends ScalaNativeOptions {
     var genStaticForwardersForNonTopLevelObjects: Boolean = false
+
+    var positionRelativizationPaths: Seq[Path] = Nil
   }
 
   object prepNativeInterop extends PrepNativeInterop[global.type](global) {
@@ -48,6 +49,16 @@ class ScalaNativePlugin(val global: Global) extends Plugin {
     options.foreach {
       case "genStaticForwardersForNonTopLevelObjects" =>
         genStaticForwardersForNonTopLevelObjects = true
+
+      case opt if opt.startsWith("positionRelativizationPaths:") =>
+        positionRelativizationPaths = {
+          positionRelativizationPaths ++ opt
+            .stripPrefix("positionRelativizationPaths:")
+            .split(';')
+            .map(Paths.get(_))
+            .filter(_.isAbsolute())
+        }.distinct.sortBy(-_.getNameCount())
+
       case opt if opt.startsWith("mapSourceURI:") =>
         global.reporter.warning(
           global.NoPosition,
@@ -65,6 +76,12 @@ class ScalaNativePlugin(val global: Global) extends Plugin {
       |     Generate static forwarders for non-top-level objects.
       |     This option should be used by codebases that implement JDK classes.
       |     When used together with -Xno-forwarders, this option has no effect.
+      |  -P:$name:positionRelativizationPaths
+      |     Change the source file positions in generated outputs based on list of provided paths.
+      |     It would strip the prefix of the source file if it matches given path.
+      |     Non-absolute paths would be ignored.
+      |     Multiple paths should be seperated by a single semicolon ';' character.
+      |     If none of the patches matches path would be relative to -sourcepath if defined or -sourceroot otherwise.
       """.stripMargin)
 
 }

nscplugin/src/main/scala-3/scala/scalanative/nscplugin/GenNIR.scala

@@ -7,6 +7,7 @@ import core._
 import Contexts._
 
 import java.net.URI
+import java.nio.file.Path
 
 class GenNIR(settings: GenNIR.Settings) extends PluginPhase {
   val phaseName = GenNIR.name
@@ -28,6 +29,10 @@ object GenNIR {
        *  this option can be used to opt in. This is necessary for
        *  implementations of JDK classes.
        */
-      genStaticForwardersForNonTopLevelObjects: Boolean = false
+      genStaticForwardersForNonTopLevelObjects: Boolean = false,
+
+      /** List of paths usd for relativization of source file positions
+       */
+      positionRelativizationPaths: Seq[Path] = Nil
   )
 }

nscplugin/src/main/scala-3/scala/scalanative/nscplugin/GenReflectiveInstantisation.scala

@@ -290,10 +290,10 @@ trait GenReflectiveInstantisation(using Context) {
     // initialising and returning an instance of the class, using C.
     for ((ctor, ctorIdx) <- ctors.zipWithIndex) {
       val ctorSig = genMethodSig(ctor)
-      val ctorArgsSig = ctorSig.args.map(_.mangle).mkString
       given nir.Position = ctor.span
+      val ctorSuffix = if (ctorIdx == 0) "" else s"$$$ctorIdx"
       given reflInstBuffer: ReflectiveInstantiationBuffer =
-        ReflectiveInstantiationBuffer(fqSymName.id + ctorArgsSig)
+        ReflectiveInstantiationBuffer(fqSymName.id + ctorSuffix)
 
       // Lambda generation consists of generating a class which extends
       // scala.runtime.AbstractFunction1, with an apply method that accepts

nscplugin/src/main/scala-3/scala/scalanative/nscplugin/NirCodeGen.scala

@@ -29,7 +29,9 @@ class NirCodeGen(val settings: GenNIR.Settings)(using ctx: Context)
 
   protected val defnNir = NirDefinitions.get
   protected val nirPrimitives = new NirPrimitives()
-  protected val positionsConversions = new NirPositions()
+  protected val positionsConversions = new NirPositions(
+    settings.positionRelativizationPaths
+  )
   protected val cachedMethodSig =
     collection.mutable.Map.empty[(Symbol, Boolean), nir.Type.Function]
 

nscplugin/src/main/scala-3/scala/scalanative/nscplugin/NirPositions.scala

@@ -7,8 +7,9 @@ import dotty.tools.dotc.util.{SourceFile, SourcePosition}
 import dotty.tools.dotc.util.Spans.Span
 import scalanative.nir
 import scala.compiletime.uninitialized
+import java.nio.file.{Path, Paths}
 
-class NirPositions()(using Context) {
+class NirPositions(positionRelativizationPaths: Seq[Path])(using Context) {
   given fromSourcePosition: Conversion[SourcePosition, nir.Position] = {
     sourcePos =>
       sourceAndSpanToNirPos(sourcePos.source, sourcePos.span)
@@ -44,16 +45,24 @@ class NirPositions()(using Context) {
       lastNIRSource
     }
 
-    private val sourceRoot =
-      if !ctx.settings.sourcepath.isDefault
-      then ctx.settings.sourcepath.value
-      else ctx.settings.sourceroot.value
+    private val sourceRoot = Paths
+      .get(
+        if !ctx.settings.sourcepath.isDefault
+        then ctx.settings.sourcepath.value
+        else ctx.settings.sourceroot.value
+      )
+      .toAbsolutePath()
     private def convert(dotcSource: SourceFile): nir.SourceFile = {
       if dotcSource.file.isVirtual
       then nir.SourceFile.Virtual
-      else
-        val sourceRelativePath = SourceFile.relativePath(dotcSource, sourceRoot)
-        nir.SourceFile.SourceRootRelative(sourceRelativePath)
+      else {
+        val absSourcePath = dotcSource.file.absolute.jpath
+        val relativeTo = positionRelativizationPaths
+          .find(absSourcePath.startsWith(_))
+          .getOrElse(sourceRoot)
+          .toString()
+        nir.SourceFile.Relative(SourceFile.relativePath(dotcSource, relativeTo))
+      }
     }
   }
 }

nscplugin/src/main/scala-3/scala/scalanative/nscplugin/ScalaNativePlugin.scala

@@ -6,6 +6,7 @@ import dotty.tools.dotc.core.Contexts.NoContext
 import java.net.URI
 import java.net.URISyntaxException
 import dotty.tools.dotc.core.Contexts.Context
+import java.nio.file.Paths
 
 class ScalaNativePlugin extends StandardPlugin:
   val name: String = "scalanative"
@@ -17,13 +18,26 @@ class ScalaNativePlugin extends StandardPlugin:
       |     Generate static forwarders for non-top-level objects.
       |     This option should be used by codebases that implement JDK classes.
       |     When used together with -Xno-forwarders, this option has no effect.
+      |  -P:$name:positionRelativizationPaths
+      |     Change the source file positions in generated outputs based on list of provided paths.
+      |     It would strip the prefix of the source file if it matches given path.
+      |     Non-absolute paths would be ignored.
+      |     Multiple paths should be seperated by a single semicolon ';' character. 
+      |     If none of the patches matches path would be relative to -sourcepath if defined or -sourceroot otherwise.
       """.stripMargin)
 
   override def init(options: List[String]): List[PluginPhase] = {
     val genNirSettings = options
       .foldLeft(GenNIR.Settings()) {
         case (config, "genStaticForwardersForNonTopLevelObjects") =>
           config.copy(genStaticForwardersForNonTopLevelObjects = true)
+        case (config, s"positionRelativizationPaths:${paths}") =>
+          config.copy(positionRelativizationPaths =
+            (config.positionRelativizationPaths ++ paths
+              .split(';')
+              .map(Paths.get(_))
+              .filter(_.isAbsolute())).distinct.sortBy(-_.getNameCount())
+          )
         case (config, s"mapSourceURI:${mapping}") =>
           given Context = NoContext
           report.warning("'mapSourceURI' is deprecated, it's ignored.")

project/Settings.scala

@@ -720,12 +720,12 @@ object Settings {
       libraryDependencies += "org.scala-lang" % libraryName % scalaVersion.value,
       fetchScalaSource / artifactPath :=
         baseDirectory.value.getParentFile / "target" / "scalaSources" / scalaVersion.value,
-      scalacOptions ++= Seq(
-        // Create nir.SourceFile relative to Scala sources dir instead of root dir
-        // It should use -sourcepath for both, but it fails to compile under Scala 2
-        if (scalaVersion.value.startsWith("2.")) "-rootdir" else "-sourcepath",
-        (fetchScalaSource / artifactPath).value.toString
-      ),
+      // Create nir.SourceFile relative to Scala sources dir instead of root dir
+      // It should use -sourcepath for both, but it fails to compile under Scala 2
+      scalacOptions ++=
+        scalaNativeCompilerOptions(
+          s"positionRelativizationPaths:${crossTarget.value / "patched"};${(fetchScalaSource / artifactPath).value}"
+        ),
       // Scala.js original comment modified to clarify issue is Scala.js.
       /* Work around for https://github.com/scala-js/scala-js/issues/2649
        * We would like to always use `update`, but

sbt-scala-native/src/main/scala/scala/scalanative/sbtplugin/ScalaNativePluginInternal.scala

@@ -188,6 +188,8 @@ object ScalaNativePluginInternal {
    *  times per project.
    */
   def scalaNativeConfigSettings(testConfig: Boolean): Seq[Setting[_]] = Seq(
+    scalacOptions +=
+      s"-P:scalanative:positionRelativizationPaths:${sourceDirectories.value.map(_.getAbsolutePath()).mkString(";")}",
     nativeLinkReleaseFull := Def
       .task {
         val sbtLogger = streams.value.log