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/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Martin Odersky
*/
package scala.tools.nsc
package transform
import symtab._
import Flags._
import scala.collection.{ mutable, immutable }
import scala.collection.mutable.ListBuffer
abstract class Flatten extends InfoTransform {
import global._
import definitions._
/** the following two members override abstract members in Transform */
val phaseName: String = "flatten"
/** Updates the owning scope with the given symbol; returns the old symbol.
*/
private def replaceSymbolInCurrentScope(sym: Symbol): Symbol = afterFlatten {
val scope = sym.owner.info.decls
val old = scope lookup sym.name andAlso scope.unlink
scope enter sym
if (old eq NoSymbol)
log(s"lifted ${sym.fullLocationString}")
else
log(s"lifted ${sym.fullLocationString} after unlinking existing $old from scope.")
old
}
private def liftClass(sym: Symbol) {
if (!sym.isLifted) {
sym setFlag LIFTED
debuglog("re-enter " + sym.fullLocationString)
replaceSymbolInCurrentScope(sym)
}
}
private def liftSymbol(sym: Symbol) {
liftClass(sym)
if (sym.needsImplClass)
liftClass(erasure implClass sym)
}
// This is a short-term measure partially working around objects being
// lifted out of parameterized classes, leaving them referencing
// invisible type parameters.
private def isFlattenablePrefix(pre: Type) = {
val clazz = pre.typeSymbol
clazz.isClass && !clazz.isPackageClass && {
// Cannot flatten here: class A[T] { object B }
// was "at erasurePhase.prev"
beforeErasure(clazz.typeParams.isEmpty)
}
}
private val flattened = new TypeMap {
def apply(tp: Type): Type = tp match {
case TypeRef(pre, sym, args) if isFlattenablePrefix(pre) =>
assert(args.isEmpty && sym.enclosingTopLevelClass != NoSymbol, sym.ownerChain)
typeRef(sym.enclosingTopLevelClass.owner.thisType, sym, Nil)
case ClassInfoType(parents, decls, clazz) =>
var parents1 = parents
val decls1 = scopeTransform(clazz) {
val decls1 = newScope
if (clazz.isPackageClass) {
afterFlatten { decls foreach (decls1 enter _) }
}
else {
val oldowner = clazz.owner
afterFlatten { oldowner.info }
parents1 = parents mapConserve (this)
for (sym <- decls) {
if (sym.isTerm && !sym.isStaticModule) {
decls1 enter sym
if (sym.isModule)
sym.moduleClass setFlag LIFTED
} else if (sym.isClass)
liftSymbol(sym)
}
}
decls1
}
ClassInfoType(parents1, decls1, clazz)
case MethodType(params, restp) =>
val restp1 = apply(restp)
if (restp1 eq restp) tp else copyMethodType(tp, params, restp1)
case PolyType(tparams, restp) =>
val restp1 = apply(restp);
if (restp1 eq restp) tp else PolyType(tparams, restp1)
case _ =>
mapOver(tp)
}
}
def transformInfo(sym: Symbol, tp: Type): Type = flattened(tp)
protected def newTransformer(unit: CompilationUnit): Transformer = new Flattener
class Flattener extends Transformer {
/** Buffers for lifted out classes */
private val liftedDefs = perRunCaches.newMap[Symbol, ListBuffer[Tree]]()
override def transform(tree: Tree): Tree = {
tree match {
case PackageDef(_, _) =>
liftedDefs(tree.symbol.moduleClass) = new ListBuffer
case Template(_, _, _) if tree.symbol.isDefinedInPackage =>
liftedDefs(tree.symbol.owner) = new ListBuffer
case _ =>
}
postTransform(super.transform(tree))
}
private def postTransform(tree: Tree): Tree = {
val sym = tree.symbol
val tree1 = tree match {
case ClassDef(_, _, _, _) if sym.isNestedClass =>
liftedDefs(sym.enclosingTopLevelClass.owner) += tree
EmptyTree
case Select(qual, name) if (sym.isStaticModule && !sym.owner.isPackageClass) =>
afterFlatten(atPos(tree.pos)(gen.mkAttributedRef(sym)))
case _ =>
tree
}
tree1 setType flattened(tree1.tpe)
}
/** Transform statements and add lifted definitions to them. */
override def transformStats(stats: List[Tree], exprOwner: Symbol): List[Tree] = {
val stats1 = super.transformStats(stats, exprOwner)
if (currentOwner.isPackageClass) stats1 ::: liftedDefs(currentOwner).toList
else stats1
}
}
}
|
