moves reflective compiler into scala.tools.reflect

1 files changed, 40 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/reflect/ReflectGlobal.scala b/src/compiler/scala/tools/reflect/ReflectGlobal.scala
new file mode 100644
index 0000000000..f8ded56ec6
--- /dev/null
+++ b/src/compiler/scala/tools/reflect/ReflectGlobal.scala
@@ -0,0 +1,40 @@
+package scala.tools
+package reflect
+
+import scala.tools.nsc.Global
+import scala.tools.nsc.reporters.Reporter
+import scala.tools.nsc.Settings
+
+/** A version of Global that uses reflection to get class
+ *  infos, instead of reading class or source files.
+ */
+class ReflectGlobal(currentSettings: Settings, reporter: Reporter, override val rootClassLoader: ClassLoader)
+  extends Global(currentSettings, reporter) with scala.tools.reflect.ReflectSetup with scala.reflect.runtime.SymbolTable {
+
+  override def transformedType(sym: Symbol) =
+    erasure.transformInfo(sym,
+      uncurry.transformInfo(sym,
+        refChecks.transformInfo(sym, sym.info)))
+
+  override def isCompilerUniverse = true
+
+  // Typically `runtimeMirror` creates a new mirror for every new classloader
+  // and shares symbols between the created mirrors.
+  //
+  // However we can't do that for the compiler.
+  // The problem is that symbol sharing violates owner chain assumptions that the compiler has.
+  //
+  // For example, we can easily end up with a situation when:
+  //
+  //   Predef defined in package scala loaded by the classloader that has scala-library.jar
+  //
+  // cannot be accessed in:
+  //
+  //   package scala for the rootMirror of ReflectGlobal that might correspond to a different classloader
+  //
+  // This happens because, despite the fact that `Predef` is shared between multiple `scala` packages (i.e. multiple scopes)
+  // (each mirror has its own set package symbols, because of the peculiarities of symbol loading in scala),
+  // that `Predef` symbol only has a single owner, and this messes up visibility, which is calculated based on owners, not scopes.
+  override def runtimeMirror(cl: ClassLoader): Mirror = rootMirror
+}
+