Cache classloaders in Splicer

compiler/src/dotty/tools/dotc/transform/ReifyQuotes.scala

@@ -88,6 +88,16 @@ import dotty.tools.dotc.core.quoted._
 class ReifyQuotes extends MacroTransformWithImplicits with InfoTransformer {
   import ast.tpd._
 
+  /** Classloader used for loading macros */
+  private[this] var myMacroClassLoader: java.lang.ClassLoader = _
+  private def macroClassLoader(implicit ctx: Context): ClassLoader = {
+    if (myMacroClassLoader == null) {
+      val urls = ctx.settings.classpath.value.split(':').map(cp => java.nio.file.Paths.get(cp).toUri.toURL)
+      myMacroClassLoader = new java.net.URLClassLoader(urls, getClass.getClassLoader)
+    }
+    myMacroClassLoader
+  }
+
   override def phaseName: String = "reifyQuotes"
 
   override def run(implicit ctx: Context): Unit =
@@ -542,7 +552,7 @@ class ReifyQuotes extends MacroTransformWithImplicits with InfoTransformer {
                 // Simplification of the call done in PostTyper for non-macros can also be performed now
                 // see PostTyper `case Inlined(...) =>` for description of the simplification
                 val call2 = Ident(call.symbol.topLevelClass.typeRef).withPos(call.pos)
-                val spliced = Splicer.splice(body, call, bindings, tree.pos).withPos(tree.pos)
+                val spliced = Splicer.splice(body, call, bindings, tree.pos, macroClassLoader).withPos(tree.pos)
                 transform(cpy.Inlined(tree)(call2, bindings, spliced))
               }
               else super.transform(tree)

compiler/src/dotty/tools/dotc/transform/Splicer.scala

@@ -30,16 +30,13 @@ object Splicer {
    *
    *  See: `ReifyQuotes`
    */
-  def splice(tree: Tree, call: Tree, bindings: List[Tree], pos: Position)(implicit ctx: Context): Tree = tree match {
+  def splice(tree: Tree, call: Tree, bindings: List[Tree], pos: Position, classLoader: ClassLoader)(implicit ctx: Context): Tree = tree match {
     case Quoted(quotedTree) => quotedTree
-    case _ => reflectiveSplice(tree, call, bindings, pos)
-  }
-
-  private def reflectiveSplice(tree: Tree, call: Tree, bindings: List[Tree], pos: Position)(implicit ctx: Context): Tree = {
-    val liftedArgs = getLiftedArgs(call, bindings)
-    val interpreter = new Interpreter(pos)
-    val interpreted = interpreter.interpretCallToSymbol[Seq[Any] => Object](call.symbol)
-    interpreted.flatMap(lambda => evaluateLambda(lambda, liftedArgs, pos)).fold(tree)(PickledQuotes.quotedExprToTree)
+    case _ =>
+      val liftedArgs = getLiftedArgs(call, bindings)
+      val interpreter = new Interpreter(pos, classLoader)
+      val interpreted = interpreter.interpretCallToSymbol[Seq[Any] => Object](call.symbol)
+      interpreted.flatMap(lambda => evaluateLambda(lambda, liftedArgs, pos)).fold(tree)(PickledQuotes.quotedExprToTree)
   }
 
   /** Given the inline code and bindings, compute the lifted arguments that will be used to execute the macro
@@ -98,12 +95,7 @@ object Splicer {
    *  The interpreter assumes that all calls in the trees are to code that was
    *  previously compiled and is present in the classpath of the current context.
    */
-  private class Interpreter(pos: Position)(implicit ctx: Context) {
-
-    private[this] val classLoader = {
-      val urls = ctx.settings.classpath.value.split(':').map(cp => java.nio.file.Paths.get(cp).toUri.toURL)
-      new URLClassLoader(urls, getClass.getClassLoader)
-    }
+  private class Interpreter(pos: Position, classLoader: ClassLoader)(implicit ctx: Context) {
 
     /** Returns the interpreted result of interpreting the code a call to the symbol with default arguments.
      *  Return Some of the result or None if some error happen during the interpretation.