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package dotty.tools.dotc
package transform
import TreeTransforms._
import core.DenotTransformers._
import core.Symbols._
import core.Contexts._
import core.Types._
import core.Flags._
import core.Decorators._
import core.SymDenotations._
import core.StdNames.nme
import core.Names._
import core.NameOps._
import ast.Trees._
import SymUtils._
import collection.{ mutable, immutable }
import collection.mutable.{ LinkedHashMap, LinkedHashSet, TreeSet }
class CapturedVars extends MiniPhaseTransform with IdentityDenotTransformer { thisTransform =>
import ast.tpd._
/** the following two members override abstract members in Transform */
val phaseName: String = "capturedVars"
override def treeTransformPhase = thisTransform.next
private var captured: mutable.HashSet[Symbol] = _
private class CollectCaptured(implicit ctx: Context) extends EnclosingMethodTraverser {
def traverse(enclMeth: Symbol, tree: Tree) = tree match {
case id: Ident =>
val sym = id.symbol
if (sym.is(Mutable, butNot = Method) && sym.owner.isTerm && sym.enclosingMethod != enclMeth) {
ctx.log(i"capturing $sym in ${sym.enclosingMethod}, referenced from $enclMeth")
captured += sym
}
case _ =>
foldOver(enclMeth, tree)
}
def runOver(tree: Tree) = {
captured = mutable.HashSet()
apply(NoSymbol, tree)
}
}
override def prepareForUnit(tree: Tree)(implicit ctx: Context) = {
(new CollectCaptured)(ctx.withPhase(thisTransform)).runOver(ctx.compilationUnit.tpdTree)
this
}
/** The {Volatile|}{Int|Double|...|Object}Ref class corresponding to the class `cls`,
* depending on whether the reference should be @volatile
*/
def refCls(cls: Symbol, isVolatile: Boolean)(implicit ctx: Context): Symbol = {
val refMap = if (isVolatile) defn.volatileRefClass else defn.refClass
refMap.getOrElse(cls, refMap(defn.ObjectClass))
}
def capturedType(vble: Symbol)(implicit ctx: Context): Type = {
val oldInfo = vble.denot(ctx.withPhase(thisTransform)).info
refCls(oldInfo.classSymbol, vble.isVolatile).typeRef
}
override def prepareForValDef(vdef: ValDef)(implicit ctx: Context) = {
val sym = vdef.symbol
if (captured contains sym) {
val newd = sym.denot(ctx.withPhase(thisTransform)).copySymDenotation(
info = refCls(sym.info.classSymbol, sym.hasAnnotation(defn.VolatileAnnot)).typeRef)
newd.removeAnnotation(defn.VolatileAnnot)
newd.installAfter(thisTransform)
}
this
}
override def transformValDef(vdef: ValDef)(implicit ctx: Context, info: TransformerInfo): Tree = {
val vble = vdef.symbol
if (captured contains vble) {
def boxMethod(name: TermName): Tree =
ref(vble.info.classSymbol.companionModule.info.member(name).symbol)
cpy.ValDef(vdef)(
rhs = vdef.rhs match {
case EmptyTree => boxMethod(nme.zero).appliedToNone.withPos(vdef.pos)
case arg => boxMethod(nme.create).appliedTo(arg)
},
tpt = TypeTree(vble.info).withPos(vdef.tpt.pos))
}
else vdef
}
override def transformIdent(id: Ident)(implicit ctx: Context, info: TransformerInfo): Tree = {
val vble = id.symbol
if (captured(vble))
(id select nme.elem).ensureConforms(vble.denot(ctx.withPhase(thisTransform)).info)
else id
}
override def transformAssign(tree: Assign)(implicit ctx: Context, info: TransformerInfo): Tree = {
val lhs1 = tree.lhs match {
case TypeApply(Select(qual @ Select(qual2, nme.elem), nme.asInstanceOf_), _) =>
assert(captured(qual2.symbol))
qual
case _ => tree.lhs
}
cpy.Assign(tree)(lhs1, tree.rhs)
}
}
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