Add support for nativeLto options in command line and using directives

modules/cli/src/main/scala/scala/cli/commands/shared/ScalaNativeOptions.scala

@@ -23,6 +23,10 @@ final case class ScalaNativeOptions(
   @Tag(tags.should)
     nativeMode: Option[String] = None,
   @Group(HelpGroup.ScalaNative.toString)
+  @HelpMessage("Link-time optimisation mode")
+  @Tag(tags.should)
+    nativeLto: Option[String] = None,
+  @Group(HelpGroup.ScalaNative.toString)
   @HelpMessage("Set the Scala Native garbage collector")
   @Tag(tags.should)
     nativeGc: Option[String] = None,

modules/cli/src/main/scala/scala/cli/commands/shared/SharedOptions.scala

@@ -245,6 +245,7 @@ final case class SharedOptions(
     options.ScalaNativeOptions(
       nativeVersion,
       nativeMode,
+      nativeLto,
       nativeGc,
       nativeClang,
       nativeClangpp,

modules/directives/src/main/scala/scala/build/preprocessing/directives/ScalaNative.scala

@@ -14,6 +14,8 @@ import scala.cli.commands.SpecificationLevel
     |
     |`//> using nativeMode` _value_
     |
+    |`//> using nativeLto` _value_
+    |
     |`//> using nativeVersion` _value_
     |
     |`//> using nativeCompile` _value1_, _value2_
@@ -32,6 +34,7 @@ import scala.cli.commands.SpecificationLevel
 final case class ScalaNative(
   nativeGc: Option[String] = None,
   nativeMode: Option[String] = None,
+  nativeLto: Option[String] = None,
   nativeVersion: Option[String] = None,
   nativeCompile: List[String] = Nil,
   nativeLinking: List[String] = Nil,
@@ -45,6 +48,7 @@ final case class ScalaNative(
     val nativeOptions = ScalaNativeOptions(
       gcStr = nativeGc,
       modeStr = nativeMode,
+      ltoStr = nativeLto,
       version = nativeVersion,
       compileOptions = nativeCompile,
       linkingOptions = nativeLinking,

modules/integration/src/test/scala/scala/cli/integration/RunScalaNativeTestDefinitions.scala

@@ -33,6 +33,28 @@ trait RunScalaNativeTestDefinitions { _: RunTestDefinitions =>
     simpleNativeTests()
   }
 
+  def scalaNativeLtoTests(): Unit = {
+    val fileName = "hello.sc"
+    val message  = "Hello"
+    val inputs = TestInputs(
+      os.rel / fileName ->
+        s"""//> using nativeLto "thin"
+           |println("$message")
+           |""".stripMargin
+    )
+    inputs.fromRoot { root =>
+      val output =
+        os.proc(TestUtil.cli, extraOptions, fileName, "--native")
+          .call(cwd = root)
+          .out.trim()
+      expect(output == message)
+    }
+  }
+
+  test("scala native with lto optimisation") {
+    scalaNativeLtoTests()
+  }
+
   test("simple script native command") {
     val fileName = "simple.sc"
     val message  = "Hello"

modules/options/src/main/scala/scala/build/options/ScalaNativeOptions.scala

@@ -6,11 +6,13 @@ import dependency._
 import java.nio.file.Paths
 
 import scala.build.internal.Constants
+import scala.scalanative.build.LTO
 import scala.scalanative.{build => sn}
 
 final case class ScalaNativeOptions(
   version: Option[String] = None,
   modeStr: Option[String] = None,
+  ltoStr: Option[String] = None,
   gcStr: Option[String] = None,
   clang: Option[String] = None,
   clangpp: Option[String] = None,
@@ -65,7 +67,10 @@ final case class ScalaNativeOptions(
 
   private def compileCliOptions(): List[String] =
     finalCompileOptions().flatMap(option => List("--compile-option", option))
-
+  private def ltoOptions(): List[String] =
+    ltoStr.map(_.trim).filter(_.nonEmpty)
+      .map(lto => LTO.apply(lto))
+      .map(lto => List("--lto", lto.name)).getOrElse(Nil)
   private def resourcesCliOptions(resourcesExist: Boolean): List[String] =
     if (embedResources.getOrElse(true))
       (numeralVersion, resourcesExist) match {
@@ -113,6 +118,7 @@ final case class ScalaNativeOptions(
   def configCliOptions(resourcesExist: Boolean): List[String] =
     gcCliOption() ++
       modeCliOption() ++
+      ltoOptions() ++
       clangCliOption() ++
       clangppCliOption() ++
       linkingCliOptions() ++

website/docs/reference/cli-options.md

@@ -1285,12 +1285,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 ### `--native-version`
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 ### `--native-mode`
 
 Set Scala Native compilation mode
 
+### `--native-lto`
+
+Link-time optimisation mode
+
 ### `--native-gc`
 
 Set the Scala Native garbage collector

website/docs/reference/directives.md

@@ -242,6 +242,8 @@ Add Scala Native options
 
 `//> using nativeMode` _value_
 
+`//> using nativeLto` _value_
+
 `//> using nativeVersion` _value_
 
 `//> using nativeCompile` _value1_, _value2_

website/docs/reference/scala-command/cli-options.md

@@ -794,14 +794,20 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 `SHOULD have` per Scala Runner specification
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 ### `--native-mode`
 
 `SHOULD have` per Scala Runner specification
 
 Set Scala Native compilation mode
 
+### `--native-lto`
+
+`SHOULD have` per Scala Runner specification
+
+Link-time optimisation mode
+
 ### `--native-gc`
 
 `SHOULD have` per Scala Runner specification

website/docs/reference/scala-command/directives.md

@@ -187,6 +187,8 @@ Add Scala Native options
 
 `//> using nativeMode` _value_
 
+`//> using nativeLto` _value_
+
 `//> using nativeVersion` _value_
 
 `//> using nativeCompile` _value1_, _value2_

website/docs/reference/scala-command/runner-specification.md

@@ -158,12 +158,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -864,12 +868,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -1387,12 +1395,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -1936,12 +1948,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -2504,12 +2520,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -3048,12 +3068,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -3629,12 +3653,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -4255,12 +4283,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector
@@ -5094,12 +5126,16 @@ Enable Scala Native. To show more options for Scala Native pass `--help-native`
 
 **--native-version**
 
-Set the Scala Native version (0.4.9 by default).
+Set the Scala Native version (0.4.12 by default).
 
 **--native-mode**
 
 Set Scala Native compilation mode
 
+**--native-lto**
+
+Link-time optimisation mode
+
 **--native-gc**
 
 Set the Scala Native garbage collector