Remove scala-backend submodule

Author: OlivierBlanvillain

.gitmodules

@@ -1,7 +1,3 @@
-[submodule "scala-backend"]
-	path = scala-backend
-	url = https://github.com/lampepfl/scala.git
-	branch = sharing-backend
 [submodule "scala2-library"]
 	path = scala2-library
 	url = https://github.com/lampepfl/scala.git

.vscode-template/settings.json

@@ -11,12 +11,6 @@
     "**/target/": true,
     "community-build/community-projects": true,
     "scala2-library/{doc,docs,lib,META-INF,scripts,spec,test,tools}/": true, // only allow scala-backend/src
-    "scala2-library/src/[abcefimprs]*": true,  // only allow scala-backend/src/library
-    "scala-backend/{doc,docs,lib,META-INF,scripts,spec,test,tools}/": true, // only allow scala-backend/src
-    "scala-backend/src/[abefilmprs]*": true, // only allow scala-backend/src/compiler
-    "scala-backend/src/scala/reflect/": true,
-    "scala-backend/src/scala/tools/{ant,cmd,reflect,util}*": true,
-    "scala-backend/src/scala/tools/nsc/*.scala": true,
-    "scala-backend/src/scala/tools/nsc/[aijrstu]*": true // only allow scala-backend/src/scala/tools/nsc/backend
+    "scala2-library/src/[abcefimprs]*": true
   }
 }

compiler/src/scala/tools/nsc/io/package.scala

@@ -6,8 +6,6 @@ package scala.tools.nsc
  * Our backend is based on the Scala 2.11 GenBCode backend and modified so that
  * it compiles both with dotty and scalac, since the backend uses
  * scala.tools.nsc.io.*, we need to also provide it.
- *
- * See http://dotty.epfl.ch/docs/contributing/backend.html for more information.
  */
 package object io {
   type AbstractFile = dotty.tools.io.AbstractFile

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -15,7 +15,6 @@ import scala.concurrent.duration._
 import vulpix._
 import dotty.tools.io.JFile
 
-
 class CompilationTests extends ParallelTesting {
   import ParallelTesting._
   import TestConfiguration._
@@ -239,25 +238,11 @@ class CompilationTests extends ParallelTesting {
     val compilerDir = Paths.get("compiler/src")
     val compilerSources = sources(Files.walk(compilerDir))
 
-    val backendDir = Paths.get("scala-backend/src/compiler/scala/tools/nsc/backend")
-    val backendJvmDir = Paths.get("scala-backend/src/compiler/scala/tools/nsc/backend/jvm")
     val scalaJSIRDir = Paths.get("compiler/target/scala-2.12/src_managed/main/scalajs-ir-src/org/scalajs/ir")
+    val scalaJSIRSources = sources(Files.list(scalaJSIRDir))
 
-    // NOTE: Keep these exclusions synchronized with the ones in the sbt build (Build.scala)
-    val backendExcluded =
-      List("JavaPlatform.scala", "Platform.scala", "ScalaPrimitives.scala")
-    val backendJvmExcluded =
-      List("BCodeICodeCommon.scala", "GenASM.scala", "GenBCode.scala", "ScalacBackendInterface.scala", "BackendStats.scala", "BCodeAsmEncode.scala")
-
-    val backendSources =
-      sources(Files.list(backendDir), excludedFiles = backendExcluded)
-    val backendJvmSources =
-      sources(Files.list(backendJvmDir), excludedFiles = backendJvmExcluded)
-    val scalaJSIRSources =
-      sources(Files.list(scalaJSIRDir))
-
-    val dotty1 = compileList("dotty", compilerSources ++ backendSources ++ backendJvmSources ++ scalaJSIRSources, opt)(dotty1Group)
-    val dotty2 = compileList("dotty", compilerSources ++ backendSources ++ backendJvmSources ++ scalaJSIRSources, opt)(dotty2Group)
+    val dotty1 = compileList("dotty", compilerSources ++ scalaJSIRSources, opt)(dotty1Group)
+    val dotty2 = compileList("dotty", compilerSources ++ scalaJSIRSources, opt)(dotty2Group)
 
     val tests = {
       lib.keepOutput :: dotty1.keepOutput :: {
@@ -273,8 +258,8 @@ class CompilationTests extends ParallelTesting {
         compileShallowFilesInDir("compiler/src/dotty/tools/dotc/transform", opt) +
         compileShallowFilesInDir("compiler/src/dotty/tools/dotc/typer", opt) +
         compileShallowFilesInDir("compiler/src/dotty/tools/dotc/util", opt) +
-        compileList("shallow-backend", backendSources, opt) +
-        compileList("shallow-backend-jvm", backendJvmSources, opt) +
+        compileShallowFilesInDir("compiler/src/scala/tools/nsc/backend", opt) +
+        compileShallowFilesInDir("compiler/src/scala/tools/nsc/backend/jvm", opt) +
         compileList("shallow-scalajs-ir", scalaJSIRSources, opt)
       }.keepOutput :: Nil
     }.map(_.checkCompile())

docs/docs/contributing/backend.md

@@ -145,8 +145,6 @@ sidebar:
           url: docs/contributing/intellij-idea.html
         - title: Testing
           url: docs/contributing/testing.html
-        - title: Working with the Backend
-          url: docs/contributing/backend.html
     - title: Internals
       subsection:
         - title: Backend

docs/sidebar.yml

@@ -464,48 +464,6 @@ object Build {
 
   // Settings shared between dotty-compiler and dotty-compiler-bootstrapped
   lazy val commonDottyCompilerSettings = Seq(
-
-      // The scala-backend folder is a git submodule that contains a fork of the Scala 2.11
-      // compiler developed at https://github.com/lampepfl/scala/tree/sharing-backend.
-      // We do not compile the whole submodule, only the part of the Scala 2.11 GenBCode backend
-      // that we reuse for dotty.
-      // See http://dotty.epfl.ch/docs/contributing/backend.html for more information.
-      //
-      // NOTE: We link (or copy if symbolic links are not supported) these sources in
-      // the current project using `sourceGenerators` instead of simply
-      // referencing them using `unmanagedSourceDirectories` because the latter
-      // breaks some IDEs.
-      sourceGenerators in Compile += Def.task {
-        val outputDir = (sourceManaged in Compile).value
-
-        val submoduleCompilerDir = baseDirectory.value / ".." / "scala-backend" / "src" / "compiler"
-        val backendDir = submoduleCompilerDir / "scala" / "tools" / "nsc" / "backend"
-        val allScalaFiles = GlobFilter("*.scala")
-
-        // NOTE: Keep these exclusions synchronized with the ones in the tests (CompilationTests.scala)
-        val files = ((backendDir *
-          (allScalaFiles - "JavaPlatform.scala" - "Platform.scala" - "ScalaPrimitives.scala")) +++
-         (backendDir / "jvm") *
-          (allScalaFiles - "BCodeICodeCommon.scala" - "GenASM.scala" - "GenBCode.scala" - "ScalacBackendInterface.scala" - "BackendStats.scala")
-        ).get
-
-        val pairs = files.pair(sbt.Path.rebase(submoduleCompilerDir, outputDir))
-
-        try {
-          pairs.foreach { case (src, dst) =>
-            sbt.IO.createDirectory(dst.getParentFile)
-            if (!dst.exists)
-              Files.createSymbolicLink(/*link = */ dst.toPath, /*existing = */src.toPath)
-          }
-        } catch {
-          case _: UnsupportedOperationException | _: FileSystemException =>
-            // If the OS doesn't support symbolic links, copy the directory instead.
-            sbt.IO.copy(pairs, CopyOptions(overwrite = true, preserveLastModified = true, preserveExecutable = true))
-        }
-
-        pairs.map(_._2)
-      }.taskValue,
-
       // set system in/out for repl
       connectInput in run := true,
       outputStrategy := Some(StdoutOutput),