Add chisel plugin to mill build system. (#1572)

* add chisel plugin to mill build system.

* update for review.

1 files changed, 88 insertions, 47 deletions

diff --git a/build.sc b/build.sc
index 8ae21352..20fa9edd 100644
--- a/build.sc
+++ b/build.sc
@@ -1,4 +1,3 @@
-// Build script for mill 0.6.0
 import mill._
 import mill.scalalib._
 import mill.scalalib.publish._
@@ -30,33 +29,29 @@ def getTestVersion(dep: String, org: String = "edu.berkeley.cs") = {
 }
 
 // Since chisel contains submodule core and macros, a CommonModule is needed
-trait CommonModule extends ScalaModule with SbtModule with PublishModule {
+trait CommonModule extends CrossSbtModule with PublishModule {
   def firrtlModule: Option[PublishModule] = None
 
-  def firrtlIvyDeps = if(firrtlModule.isEmpty) Agg(
+  def firrtlIvyDeps = if (firrtlModule.isEmpty) Agg(
     getVersion("firrtl")
   ) else Agg.empty[Dep]
 
   def treadleModule: Option[PublishModule] = None
-  
-  def treadleIvyDeps = if(treadleModule.isEmpty) Agg(
+
+  def treadleIvyDeps = if (treadleModule.isEmpty) Agg(
     getTestVersion("treadle")
   ) else Agg.empty[Dep]
-  
-  def moduleDeps = super.moduleDeps ++ firrtlModule 
 
-  def ivyDeps = super.ivyDeps() ++ firrtlIvyDeps
+  override def moduleDeps = super.moduleDeps ++ firrtlModule
+
+  override def ivyDeps = super.ivyDeps() ++ firrtlIvyDeps
 
   def publishVersion = "3.4-SNAPSHOT"
 
   // 2.12.10 -> Array("2", "12", "10") -> "12" -> 12
-  protected def majorVersion = crossVersion.split('.')(1).toInt
-
-  def crossVersion: String
-
-  def scalaVersion = crossVersion
+  protected def majorVersion = crossScalaVersion.split('.')(1).toInt
 
-  def repositories() = super.repositories ++ Seq(
+  override def repositories = super.repositories ++ Seq(
     MavenRepository("https://oss.sonatype.org/content/repositories/snapshots"),
     MavenRepository("https://oss.sonatype.org/content/repositories/releases")
   )
@@ -71,12 +66,16 @@ trait CommonModule extends ScalaModule with SbtModule with PublishModule {
     case _ => Seq("-source", "1.8", "-target", "1.8")
   }
 
-  override def scalacOptions = super.scalacOptions() ++ Agg(
-    "-deprecation",
-    "-feature"
-  ) ++ scalacCrossOptions
-  
-  override def javacOptions = super.javacOptions() ++ javacCrossOptions
+  override def scalacOptions = T {
+    super.scalacOptions() ++ Agg(
+      "-deprecation",
+      "-feature"
+    ) ++ scalacCrossOptions
+  }
+
+  override def javacOptions = T {
+    super.javacOptions() ++ javacCrossOptions
+  }
 
   private val macroParadise = ivy"org.scalamacros:::paradise:2.1.1"
 
@@ -96,24 +95,35 @@ trait CommonModule extends ScalaModule with SbtModule with PublishModule {
   )
 }
 
-class chisel3CrossModule(crossVersionValue: String) extends CommonModule with PublishModule with BuildInfo { m =>
-  // different scala version shares same sources
-  // mill use foo/2.11.12 foo/2.12.12 as millSourcePath by default
-  override def millSourcePath = super.millSourcePath / os.up / os.up
+class chisel3CrossModule(val crossScalaVersion: String) extends CommonModule with BuildInfo {
+  m =>
+  /** Default behavior assumes `build.sc` in the upper path of `src`.
+    * This override makes `src` folder stay with `build.sc` in the same directory,
+    * If chisel3 is used as a sub-project, [[millSourcePath]] should be overridden to the folder where `src` located.
+    */
+  override def millSourcePath = super.millSourcePath / os.up
 
-  def crossVersion = crossVersionValue
+  override def mainClass = T {
+    Some("chisel3.stage.ChiselMain")
+  }
 
-  def mainClass = Some("chisel3.stage.ChiselMain")
+  override def moduleDeps = super.moduleDeps ++ Seq(macros, core)
 
-  override def moduleDeps = super.moduleDeps ++ Seq(macros, core) ++ firrtlModule
+  override def scalacPluginClasspath = T {
+    super.scalacPluginClasspath() ++ Agg(
+      plugin.jar()
+    )
+  }
 
   object test extends Tests {
+    override def scalacPluginClasspath: T[Loose.Agg[PathRef]] = m.scalacPluginClasspath
+
     private def ivyCrossDeps = majorVersion match {
       case i if i < 12 => Agg(ivy"junit:junit:4.13")
       case _ => Agg()
     }
-    
-    def ivyDeps = m.ivyDeps() ++ Agg(
+
+    override def ivyDeps = m.ivyDeps() ++ Agg(
       ivy"org.scalatest::scalatest:3.1.2",
       ivy"org.scalatestplus::scalacheck-1-14:3.1.1.1",
       ivy"com.github.scopt::scopt:3.7.1"
@@ -121,7 +131,9 @@ class chisel3CrossModule(crossVersionValue: String) extends CommonModule with Pu
 
     override def moduleDeps = super.moduleDeps ++ treadleModule
 
-    def testFrameworks = Seq("org.scalatest.tools.Framework")
+    def testFrameworks = T {
+      Seq("org.scalatest.tools.Framework")
+    }
 
     // a sbt-like testOnly command.
     // for example, mill -i "chisel3[2.12.12].test.testOnly" "chiselTests.BitwiseOpsSpec"
@@ -132,7 +144,7 @@ class chisel3CrossModule(crossVersionValue: String) extends CommonModule with Pu
 
   override def buildInfoPackageName = Some("chisel3")
 
-  override def buildInfoMembers: T[Map[String, String]] = T {
+  override def buildInfoMembers = T {
     Map(
       "buildInfoPackage" -> artifactName(),
       "version" -> publishVersion(),
@@ -141,33 +153,62 @@ class chisel3CrossModule(crossVersionValue: String) extends CommonModule with Pu
   }
 
   object macros extends CommonModule {
-    def firrtlModule = m.firrtlModule
+    /** millOuterCtx.segment.pathSegments didn't detect error here. */
+    override def millSourcePath = m.millSourcePath / "macros"
 
-    def crossVersion = crossVersionValue
+    override def crossScalaVersion = m.crossScalaVersion
+
+    override def firrtlModule = m.firrtlModule
   }
 
-  object core extends CommonModule { 
-    def firrtlModule = m.firrtlModule
+  object core extends CommonModule {
+    /** millOuterCtx.segment.pathSegments didn't detect error here. */
+    override def millSourcePath = m.millSourcePath / "core"
 
-    def crossVersion = crossVersionValue
+    override def crossScalaVersion = m.crossScalaVersion
 
-    def moduleDeps = super.moduleDeps ++ Seq(macros)
+    override def moduleDeps = super.moduleDeps ++ Seq(macros)
 
-    def scalacOptions = super.scalacOptions() ++ Seq(
-      "-deprecation",
-      "-explaintypes",
-      "-feature",
-      "-language:reflectiveCalls",
-      "-unchecked",
-      "-Xcheckinit",
-      "-Xlint:infer-any"
-    )
+    override def firrtlModule = m.firrtlModule
+
+    def scalacOptions = T {
+      super.scalacOptions() ++ Seq(
+        "-deprecation",
+        "-explaintypes",
+        "-feature",
+        "-language:reflectiveCalls",
+        "-unchecked",
+        "-Xcheckinit",
+        "-Xlint:infer-any"
+      )
+    }
 
     override def generatedSources = T {
       Seq(generatedBuildInfo()._2)
     }
+  }
+
+  object plugin extends CommonModule {
+    /** millOuterCtx.segment.pathSegments didn't detect error here. */
+    override def millSourcePath = m.millSourcePath / "plugin"
+
+    override def crossScalaVersion = m.crossScalaVersion
+
+    override def firrtlModule = m.firrtlModule
+
+    override def ivyDeps = Agg(
+      ivy"${scalaOrganization()}:scala-library:$crossScalaVersion"
+    )
+
+    def scalacOptions = T {
+      Seq(
+        "-Xfatal-warnings"
+      )
+    }
 
+    override def artifactName = "chisel3-plugin"
   }
+
   // make mill publish sbt compatible package
-  def artifactName = "chisel3"
+  override def artifactName = "chisel3"
 }