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|
/* NSC -- new Scala compiler
* Copyright 2005-2009 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc
package transform
import scala.tools.nsc.symtab.classfile.ClassfileConstants._
import scala.collection.mutable.{HashMap,ListBuffer}
import scala.collection.immutable.Set
import scala.tools.nsc.util.Position
import symtab._
import Flags._
abstract class Erasure extends AddInterfaces with typechecker.Analyzer with ast.TreeDSL
{
import global._ // the global environment
import definitions._ // standard classes and methods
// @S: XXX: why is this here? earsure is a typer, if you comment this
// out erasure still works, uses its own typed methods.
lazy val typerXXX = this.typer
import typerXXX.{typed} // methods to type trees
import CODE._
def typedPos(pos: Position)(tree: Tree) = typed { atPos(pos)(tree) }
val phaseName: String = "erasure"
def newTransformer(unit: CompilationUnit): Transformer =
new ErasureTransformer(unit)
// -------- erasure on types --------------------------------------------------------
/** An extractor objec for generic arrays */
object GenericArray {
/** Is `tp` an unbounded generic type (i.e. which could be instantiated
* with primitive as well as class types)?.
*/
private def genericCore(tp: Type): Type = tp match {
case TypeRef(_, argsym, _) if (argsym.isAbstractType && !(argsym.owner hasFlag JAVA)) =>
tp
case ExistentialType(tparams, restp) =>
genericCore(restp)
case _ =>
NoType
}
/** If `tp` is of the form Array[...Array[T]...] where `T` is an abstract type
* then Some(N, T) where N is the number of Array constructors enclosing `T`,
* otherwise None. Existentials on any level are ignored.
*/
def unapply(tp: Type): Option[(Int, Type)] = tp match {
case TypeRef(_, ArrayClass, List(arg)) =>
genericCore(arg) match {
case NoType =>
unapply(arg) match {
case Some((level, core)) => Some((level + 1, core))
case None => None
}
case core =>
Some(1, core)
}
case ExistentialType(tparams, restp) =>
unapply(restp)
case _ =>
None
}
}
private def unboundedGenericArrayLevel(tp: Type): Int = tp match {
case GenericArray(level, core) if !(core <:< AnyRefClass.tpe) => level
case _ => 0
}
/** <p>
* The erasure <code>|T|</code> of a type <code>T</code>. This is:
* </p>
* <ul>
* <li>For a constant type, itself.</li>
* <li>For a type-bounds structure, the erasure of its upper bound.</li>
* <li>For every other singleton type, the erasure of its supertype.</li>
* <li>
* For a typeref <code>scala.Array+[T]</code> where <code>T</code> is
* an abstract type, <code>AnyRef</code>.
* </li>
* <li>
* - For a typeref scala.Array+[T] where T is not an abstract type, scala.Array+[|T|].
* - For a typeref scala.Any or scala.AnyVal, java.lang.Object.
* - For a typeref scala.Unit, scala.runtime.BoxedUnit.
* - For a typeref P.C[Ts] where C refers to a class, |P|.C.
* - For a typeref P.C[Ts] where C refers to an alias type, the erasure of C's alias.
* - For a typeref P.C[Ts] where C refers to an abstract type, the
* erasure of C's upper bound.
* - For a non-empty type intersection (possibly with refinement),
* the erasure of its first parent.
* - For an empty type intersection, java.lang.Object
* - For a method type (Fs)scala.Unit, (|Fs|)scala#Unit.
* - For any other method type (Fs)Y, (|Fs|)|T|.
* - For a polymorphic type, the erasure of its result type
* - For the class info type of java.lang.Object, the same type without any parents
* - For a class info type of a value class, the same type without any parents
* - For any other class info type with parents Ps, the same type with
* parents |Ps|, but with duplicate references of Object removed.
* - for all other types, the type itself (with any sub-components erased)
* </li>
* </ul>
*/
val erasure = new TypeMap {
def apply(tp: Type): Type = {
tp match {
case ConstantType(_) =>
tp
case st: SubType =>
apply(st.supertype)
case TypeRef(pre, sym, args) =>
def isGeneric(tp: Type): Boolean = tp match {
case TypeRef(pre, sym, args) =>
sym.isAbstractType && !(sym.owner hasFlag JAVA) ||
sym == ArrayClass && args.length == 1 && isGeneric(args.head)
case ExistentialType(tparams, restp) =>
isGeneric(restp)
case _ =>
false
}
if (sym == ArrayClass)
if (unboundedGenericArrayLevel(tp) == 1) ObjectClass.tpe
else if (args.head.typeSymbol == NothingClass || args.head.typeSymbol == NullClass) arrayType(ObjectClass.tpe)
else typeRef(apply(pre), sym, args map this)
else if (sym == AnyClass || sym == AnyValClass || sym == SingletonClass) erasedTypeRef(ObjectClass)
else if (sym == UnitClass) erasedTypeRef(BoxedUnitClass)
else if (sym.isClass)
typeRef(apply(if (sym.owner.isClass) sym.owner.tpe else pre), sym, List())
else apply(sym.info)
case PolyType(tparams, restpe) =>
apply(restpe)
case ExistentialType(tparams, restpe) =>
apply(restpe)
case mt @ MethodType(params, restpe) =>
MethodType(
cloneSymbols(params) map (p => p.setInfo(apply(p.tpe))),
if (restpe.typeSymbol == UnitClass)
erasedTypeRef(UnitClass)
else if (settings.Xexperimental.value)
apply(mt.resultType(params map (_.tpe))) // this gets rid of DeBruijnTypes
else
apply(restpe))
case RefinedType(parents, decls) =>
if (parents.isEmpty) erasedTypeRef(ObjectClass)
else apply(parents.head)
case AnnotatedType(_, atp, _) =>
apply(atp)
case ClassInfoType(parents, decls, clazz) =>
ClassInfoType(
if ((clazz == ObjectClass) || (isValueType(clazz))) List()
else if (clazz == ArrayClass) List(erasedTypeRef(ObjectClass))
else removeDoubleObject(parents map this),
decls, clazz)
case _ =>
mapOver(tp)
}
}
}
private object NeedsSigCollector extends TypeCollector(false) {
def traverse(tp: Type) {
if (!result) {
tp match {
case st: SubType =>
traverse(st.supertype)
case TypeRef(pre, sym, args) =>
if (sym == ArrayClass) args foreach traverse
else if (sym.isTypeParameterOrSkolem || sym.isExistential || !args.isEmpty) result = true
else if (!sym.owner.isPackageClass) traverse(pre)
case PolyType(_, _) | ExistentialType(_, _) =>
result = true
case RefinedType(parents, decls) =>
if (!parents.isEmpty) traverse(parents.head)
case ClassInfoType(parents, _, _) =>
parents foreach traverse
case AnnotatedType(_, atp, _) =>
traverse(atp)
case _ =>
mapOver(tp)
}
}
}
}
private def needsJavaSig(tp: Type) = !settings.Ynogenericsig.value && NeedsSigCollector.collect(tp)
private lazy val tagOfClass = Map[Symbol,Char](
ByteClass -> BYTE_TAG,
CharClass -> CHAR_TAG,
DoubleClass -> DOUBLE_TAG,
FloatClass -> FLOAT_TAG,
IntClass -> INT_TAG,
LongClass -> LONG_TAG,
ShortClass -> SHORT_TAG,
BooleanClass -> BOOL_TAG,
UnitClass -> VOID_TAG
)
/** The Java signature of type 'info', for symbol sym. The symbol is used to give the right return
* type for constructors.
*/
def javaSig(sym: Symbol, info: Type): Option[String] = atPhase(currentRun.erasurePhase) {
def jsig(tp: Type): String = jsig2(false, List(), tp)
def jsig2(toplevel: Boolean, tparams: List[Symbol], tp0: Type): String = {
val tp = tp0.dealias
tp match {
case st: SubType =>
jsig2(toplevel, tparams, st.supertype)
case ExistentialType(tparams, tpe) =>
jsig2(toplevel, tparams, tpe)
case TypeRef(pre, sym, args) =>
def argSig(tp: Type) =
if (tparams contains tp.typeSymbol) {
val bounds = tp.typeSymbol.info.bounds
if (!(AnyRefClass.tpe <:< bounds.hi)) "+"+jsig(bounds.hi)
else if (!(bounds.lo <:< NullClass.tpe)) "-"+jsig(bounds.lo)
else "*"
} else if (tp.typeSymbol == UnitClass) {
jsig(ObjectClass.tpe)
} else {
boxedClass get tp.typeSymbol match {
case Some(boxed) => jsig(boxed.tpe)
case None => jsig(tp)
}
}
def classSig: String =
"L"+atPhase(currentRun.icodePhase)(sym.fullNameString + global.genJVM.moduleSuffix(sym)).replace('.', '/')
def classSigSuffix: String =
"."+sym.name
if (sym == ArrayClass)
ARRAY_TAG.toString+(args map jsig).mkString
else if (sym.isTypeParameterOrSkolem && !sym.owner.isTypeParameterOrSkolem /*not a higher-order type parameter, as these are suppressed*/)
TVAR_TAG.toString+sym.name+";"
else if (sym == AnyClass || sym == AnyValClass || sym == SingletonClass)
jsig(ObjectClass.tpe)
else if (sym == UnitClass)
jsig(BoxedUnitClass.tpe)
else if (sym == NothingClass)
jsig(RuntimeNothingClass.tpe)
else if (sym == NullClass)
jsig(RuntimeNullClass.tpe)
else if (isValueClass(sym))
tagOfClass(sym).toString
else if (sym.isClass)
{
if (needsJavaSig(pre)) {
val s = jsig(pre)
if (s.charAt(0) == 'L') s.substring(0, s.length - 1) + classSigSuffix
else classSig
} else classSig
} + {
if (args.isEmpty) "" else "<"+(args map argSig).mkString+">"
} + ";"
else jsig(erasure(tp))
case PolyType(tparams, restpe) =>
def hiBounds(bounds: TypeBounds): List[Type] = bounds.hi.normalize match {
case RefinedType(parents, _) => parents map normalize
case tp => List(tp)
}
def boundSig(bounds: List[Type]) = {
def isClassBound(t: Type) = !t.typeSymbol.isTrait
val classBound = bounds find isClassBound match {
case Some(t) => jsig(t)
case None => ""
}
":"+classBound+(for (t <- bounds if !isClassBound(t)) yield ":"+jsig(t)).mkString
}
assert(!tparams.isEmpty)
def paramSig(tsym: Symbol) = tsym.name+boundSig(hiBounds(tsym.info.bounds))
(if (toplevel) "<"+(tparams map paramSig).mkString+">" else "")+jsig(restpe)
case MethodType(params, restpe) =>
"("+(params map (_.tpe) map jsig).mkString+")"+
(if (restpe.typeSymbol == UnitClass || sym.isConstructor) VOID_TAG.toString else jsig(restpe))
case RefinedType(parents, decls) if (!parents.isEmpty) =>
jsig(parents.head)
case ClassInfoType(parents, _, _) =>
(parents map jsig).mkString
case AnnotatedType(_, atp, _) =>
jsig(atp)
case _ =>
val etp = erasure(tp)
if (etp eq tp) throw new UnknownSig
else jsig(etp)
}
}
if (needsJavaSig(info)) {
try {
//println("Java sig of "+sym+" is "+jsig2(true, List(), sym.info))//DEBUG
Some(jsig2(true, List(), info))
} catch {
case ex: UnknownSig => None
}
}
else None
}
class UnknownSig extends Exception
/** Type reference after erasure */
def erasedTypeRef(sym: Symbol): Type =
typeRef(erasure(sym.owner.tpe), sym, List())
/** Remove duplicate references to class Object in a list of parent classes
* todo: needed?
*/
private def removeDoubleObject(tps: List[Type]): List[Type] = tps match {
case List() => List()
case tp :: tps1 =>
if (tp.typeSymbol == ObjectClass) tp :: tps1.filter(_.typeSymbol != ObjectClass)
else tp :: removeDoubleObject(tps1)
}
/** <p>
* The symbol's erased info. This is the type's erasure, except for the
* following symbols:
* </p>
* <ul>
* <li>
* For <code>$asInstanceOf</code> : <code>[T]T</code>
* </li>
* <li>
* For <code>$isInstanceOf</code> : <code>[T]scala#Boolean</code>
* </li>
* <li>
* For class <code>Array</code> : <code>[T]C</code> where
* <code>C</code> is the erased classinfo of the <code>Array</code> class
* </li>
* <li>
* For <code>Array[T].<init></code> : <code>{scala#Int)Array[T]</code>
* </li>
* <li>
* For a type parameter : A type bounds type consisting of the erasures
* of its bounds.
* </li>
* </ul>
*/
def transformInfo(sym: Symbol, tp: Type): Type =
if (sym == Object_asInstanceOf)
sym.info
else if (sym == Object_isInstanceOf || sym == ArrayClass)
PolyType(sym.info.typeParams, erasure(sym.info.resultType))
else if (sym.isAbstractType)
mkTypeBounds(WildcardType, WildcardType)
else if (sym.isTerm && sym.owner == ArrayClass) {
if (sym.isClassConstructor)
tp match {
case MethodType(params, TypeRef(pre, sym, args)) =>
MethodType(cloneSymbols(params) map (p => p.setInfo(erasure(p.tpe))),
typeRef(erasure(pre), sym, args))
}
else if (sym.name == nme.apply)
tp
else if (sym.name == nme.update)
tp match {
case MethodType(List(index, tvar), restpe) =>
MethodType(List(index.cloneSymbol.setInfo(erasure(index.tpe)), tvar),
erasedTypeRef(UnitClass))
}
else erasure(tp)
} else if (
sym.owner != NoSymbol &&
sym.owner.owner == ArrayClass &&
sym == Array_update.paramss.head(1)) {
// special case for Array.update: the non-erased type remains, i.e. (Int,A)Unit
// since the erasure type map gets applied to every symbol, we have to catch the
// symbol here
tp
} else {
/*
val erased =
if (sym.isGetter && sym.tpe.isInstanceOf[MethodType])
erasure mapOver sym.tpe // for getters, unlike for normal methods, always convert Unit to BoxedUnit.
else
erasure(tp)
*/
transformMixinInfo(erasure(tp))
}
val deconstMap = new TypeMap {
def apply(tp: Type): Type = tp match {
case PolyType(_, _) => mapOver(tp)
case MethodType(_, _) => mapOver(tp)
case _ => tp.deconst
}
}
private def isSeqClass(sym: Symbol) =
(SeqClass isNonBottomSubClass sym) && (sym != ObjectClass)
/** The symbol which is called by a bridge;
* @pre phase > erasure
*/
def bridgedSym(bridge: Symbol) =
bridge.owner.info.nonPrivateDecl(bridge.name) suchThat {
sym => !(sym hasFlag BRIDGE) &&
matchesType(sym.tpe, bridge.tpe, true) &&
sym.tpe.resultType <:< bridge.tpe.resultType
}
// -------- boxing/unboxing --------------------------------------------------------
override def newTyper(context: Context) = new Eraser(context)
/** The modifier typer which retypes with erased types. */
class Eraser(context: Context) extends Typer(context) {
/** Box `tree' of unboxed type */
private def box(tree: Tree): Tree = tree match {
case LabelDef(name, params, rhs) =>
val rhs1 = box(rhs)
treeCopy.LabelDef(tree, name, params, rhs1) setType rhs1.tpe
case _ =>
typedPos(tree.pos)(tree.tpe.typeSymbol match {
case UnitClass =>
if (treeInfo isPureExpr tree) REF(BoxedUnit_UNIT)
else BLOCK(tree, REF(BoxedUnit_UNIT))
case x =>
assert(x != ArrayClass)
(REF(boxMethod(x)) APPLY tree) setPos (tree.pos) setType ObjectClass.tpe
})
}
/** generate ScalaRuntime.boxArray(tree)
* !!! todo: optimize this in case the runtime type is known
*/
private def boxArray(tree: Tree): Tree = tree match {
case LabelDef(name, params, rhs) =>
val rhs1 = boxArray(rhs)
treeCopy.LabelDef(tree, name, params, rhs1) setType rhs1.tpe
case _ =>
typedPos(tree.pos) { gen.mkRuntimeCall(nme.boxArray, List(tree)) }
}
/** Unbox <code>tree</code> of boxed type to expected type <code>pt</code>.
*
* @param tree the given tree
* @param pt the expected type.
* @return the unboxed tree
*/
private def unbox(tree: Tree, pt: Type): Tree = tree match {
case LabelDef(name, params, rhs) =>
val rhs1 = unbox(rhs, pt)
treeCopy.LabelDef(tree, name, params, rhs1) setType rhs1.tpe
case _ =>
typedPos(tree.pos)(pt.typeSymbol match {
case UnitClass =>
if (treeInfo isPureExpr tree) UNIT
else BLOCK(tree, UNIT)
case x =>
assert(x != ArrayClass)
(REF(unboxMethod(pt.typeSymbol)) APPLY tree) setType pt
})
}
/** Generate a synthetic cast operation from <code>tree.tpe</code> to <code>pt</code>.
*/
private def cast(tree: Tree, pt: Type): Tree =
tree AS_ATTR pt
/** Is symbol a member of unboxed arrays (which will be expanded directly
* later)?
*
* @param sym ..
* @return <code>true</code> if ..
*/
private def isUnboxedArrayMember(sym: Symbol) = sym.name match {
case nme.apply | nme.length | nme.update => true
case _ => sym.owner == ObjectClass
}
private def isUnboxedValueMember(sym: Symbol) =
sym != NoSymbol && isValueClass(sym.owner)
/** Adapt <code>tree</code> to expected type <code>pt</code>.
*
* @param tree the given tree
* @param pt the expected type.
* @return the adapted tree
*/
private def adaptToType(tree: Tree, pt: Type): Tree = {
if (settings.debug.value && pt != WildcardType)
log("adapting " + tree + ":" + tree.tpe + " : " + tree.tpe.parents + " to " + pt)//debug
if (tree.tpe <:< pt)
tree
else if (isValueClass(tree.tpe.typeSymbol) && !isValueClass(pt.typeSymbol))
adaptToType(box(tree), pt)
else if (tree.tpe.isInstanceOf[MethodType] && tree.tpe.paramTypes.isEmpty) {
if (!tree.symbol.isStable) assert(false, "adapt "+tree+":"+tree.tpe+" to "+pt)
adaptToType(Apply(tree, List()) setPos tree.pos setType tree.tpe.resultType, pt)
} else if (pt <:< tree.tpe)
cast(tree, pt)
else if (isValueClass(pt.typeSymbol) && !isValueClass(tree.tpe.typeSymbol))
adaptToType(unbox(tree, pt), pt)
else
cast(tree, pt)
}
/** <p>
* Replace member references as follows:
* </p>
* <ul>
* <li>
* <code>x == y</code> for <code>==</code> in class <code>Any</code>
* becomes <code>x equals y</code> with <code>equals</code> in class
* <code>Object</code>.
* </li>
* <li>
* <code>x != y</code> for <code>!=</code> in class <code>Any</code>
* becomes <code>!(x equals y)</code> with <code>equals</code> in
* class <code>Object</code>.
* </li>
* <li>
* <code>new BoxedArray.<init>(len)</code> becomes
* <code>new BoxedAnyArray.<init>(len): BoxedArray</code>
* (the widening typing is necessary so that subsequent member
* symbols stay the same)
* </li>
* <li>
* <code>x.asInstanceOf[T]</code> and <code>x.asInstanceOf$erased[T]</code>
* become <code>x.$asInstanceOf[T]</code>
* </li>
* <li>
* <code>x.isInstanceOf[T]</code> and <code>x.isInstanceOf$erased[T]</code>
* become <code>x.$isInstanceOf[T]</code>
* </li>
* <li>
* <code>x.m</code> where <code>m</code> is some other member of
* <code>Any</code> becomes <code>x.m</code> where m is a member
* of class <code>Object</code>
* </li>
* <li>
* <code>x.m</code> where <code>x</code> has unboxed value type
* <code>T</code> and <code>m</code> is not a directly translated
* member of <code>T</code> becomes <code>T.box(x).m</code>
* </li>
* <li>
* <code>x.m</code> where <code>x</code> has type <code>Array[T]</code>
* and <code>m</code> is not a directly translated member of
* <code>Array</code> becomes <code>new BoxedTArray.<init>(x).m</code>
* </li>
* <li>
* <code>x.m</code> where <code>x</code> is a reference type and
* <code>m</code> is a directly translated member of value type
* <code>T</code> becomes <code>x.TValue().m</code>
* </li>
* <li>
* All forms of <code>x.m</code> where <code>x</code> is a boxed type
* and <code>m</code> is a member of an unboxed class become
* <code>x.m</code> where <code>m</code> is the corresponding member
* of the boxed class.
* </li>
* </ul>
*/
private def adaptMember(tree: Tree): Tree = {
//Console.println("adaptMember: " + tree);
tree match {
case Apply(TypeApply(sel @ Select(qual, name), List(targ)), List()) if tree.symbol == Any_asInstanceOf =>
val qual1 = typedQualifier(qual)
val qualClass = qual1.tpe.typeSymbol
val targClass = targ.tpe.typeSymbol
/*
if (isNumericValueClass(qualClass) && isNumericValueClass(targClass))
// convert numeric type casts
atPos(tree.pos)(Apply(Select(qual1, "to" + targClass.name), List()))
else
*/
if (isValueType(targClass)) unbox(qual1, targ.tpe)
else tree
case Select(qual, name) if (name != nme.CONSTRUCTOR) =>
if (tree.symbol == NoSymbol)
tree
else if (tree.symbol == Any_asInstanceOf)
adaptMember(atPos(tree.pos)(Select(qual, Object_asInstanceOf)))
else if (tree.symbol == Any_isInstanceOf)
adaptMember(atPos(tree.pos)(Select(qual, Object_isInstanceOf)))
else if (tree.symbol.owner == AnyClass)
adaptMember(atPos(tree.pos)(Select(qual, getMember(ObjectClass, name))))
else {
var qual1 = typedQualifier(qual);
if ((isValueType(qual1.tpe.typeSymbol) && !isUnboxedValueMember(tree.symbol)))
qual1 = box(qual1)
else if (!isValueType(qual1.tpe.typeSymbol) && isUnboxedValueMember(tree.symbol))
qual1 = unbox(qual1, tree.symbol.owner.tpe)
if (isValueClass(tree.symbol.owner) && !isValueClass(qual1.tpe.typeSymbol))
tree.symbol = NoSymbol
else if (qual1.tpe.isInstanceOf[MethodType] && qual1.tpe.paramTypes.isEmpty) {
assert(qual1.symbol.isStable, qual1.symbol);
qual1 = Apply(qual1, List()) setPos qual1.pos setType qual1.tpe.resultType
} else if (!(qual1.isInstanceOf[Super] || (qual1.tpe.typeSymbol isSubClass tree.symbol.owner))) {
// println("member cast "+tree.symbol+" "+tree.symbol.ownerChain+" "+qual1+" "+qual1.tpe)
qual1 = cast(qual1, tree.symbol.owner.tpe)
}
treeCopy.Select(tree, qual1, name)
}
case _ =>
tree
}
}
/** A replacement for the standard typer's <code>adapt</code> method.
*
* @param tree ...
* @param mode ...
* @param pt ...
* @return the adapted tree
*/
override protected def adapt(tree: Tree, mode: Int, pt: Type): Tree =
adaptToType(tree, pt)
/** A replacement for the standard typer's `typed1' method */
override protected def typed1(tree: Tree, mode: Int, pt: Type): Tree = {
var tree1 = try {
super.typed1(adaptMember(tree), mode, pt)
} catch {
case ex: Exception =>
//if (settings.debug.value)
Console.println("exception when typing " + tree);
throw ex
case er: TypeError =>
Console.println("exception when typing " + tree)
Console.println(er.msg + " in file " + context.owner.sourceFile)
er.printStackTrace
throw new Error
}
def adaptCase(cdef: CaseDef): CaseDef = {
val body1 = adaptToType(cdef.body, tree1.tpe)
treeCopy.CaseDef(cdef, cdef.pat, cdef.guard, body1) setType body1.tpe
}
def adaptBranch(branch: Tree): Tree =
if (branch == EmptyTree) branch else adaptToType(branch, tree1.tpe);
tree1 match {
case If(cond, thenp, elsep) =>
treeCopy.If(tree1, cond, adaptBranch(thenp), adaptBranch(elsep))
case Match(selector, cases) =>
treeCopy.Match(tree1, selector, cases map adaptCase)
case Try(block, catches, finalizer) =>
treeCopy.Try(tree1, adaptBranch(block), catches map adaptCase, finalizer)
case Ident(_) | Select(_, _) =>
if (tree1.symbol hasFlag OVERLOADED) {
val first = tree1.symbol.alternatives.head
val sym1 = tree1.symbol.filter {
alt => alt == first || !(first.tpe looselyMatches alt.tpe)
}
if (tree.symbol ne sym1) {
tree1.symbol = sym1
tree1.tpe = sym1.tpe
}
}
tree1
case _ =>
tree1
}
}
}
/** The erasure transformer */
class ErasureTransformer(unit: CompilationUnit) extends Transformer {
/** <p>
* Emit an error if there is a double definition. This can happen in
* the following circumstances:
* </p>
* <ul>
* <li>
* A template defines two members with the same name and erased type.
* </li>
* <li>
* A template defines and inherits two members <code>m</code> with
* different types, but their erased types are the same.
* </li>
* <li>
* A template inherits two members <code>m</code> with different
* types, but their erased types are the same.
* </li>
* </ul>
*/
private def checkNoDoubleDefs(root: Symbol) {
def doubleDefError(sym1: Symbol, sym2: Symbol) {
// the .toString must also be computed at the earlier phase
def atRefc[T](op: => T) = atPhase[T](currentRun.refchecksPhase.next)(op)
val tpe1 = atRefc(root.thisType.memberType(sym1))
val tpe2 = atRefc(root.thisType.memberType(sym2))
if (!tpe1.isErroneous && !tpe2.isErroneous)
unit.error(
if (sym1.owner == root) sym1.pos else root.pos,
(if (sym1.owner == sym2.owner) "double definition:\n"
else if (sym1.owner == root) "name clash between defined and inherited member:\n"
else "name clash between inherited members:\n") +
sym1 + ":" + atRefc(tpe1.toString) +
(if (sym1.owner == root) "" else sym1.locationString) + " and\n" +
sym2 + ":" + atRefc(tpe2.toString) +
(if (sym2.owner == root) " at line " + (sym2.pos).line else sym2.locationString) +
"\nhave same type" +
(if (atRefc(tpe1 =:= tpe2)) "" else " after erasure: " + atPhase(phase.next)(sym1.tpe)))
sym1.setInfo(ErrorType)
}
val decls = root.info.decls
var e = decls.elems
while (e ne null) {
if (e.sym.isTerm) {
var e1 = decls.lookupNextEntry(e)
while (e1 ne null) {
if (atPhase(phase.next)(e1.sym.info =:= e.sym.info)) doubleDefError(e.sym, e1.sym)
e1 = decls.lookupNextEntry(e1)
}
}
e = e.next
}
val opc = new overridingPairs.Cursor(root) {
override def exclude(sym: Symbol): Boolean =
(!sym.isTerm || sym.hasFlag(PRIVATE) || super.exclude(sym)
// specialized members have no type history before 'specialize', causing duble def errors for curried defs
|| !sym.hasTypeAt(currentRun.refchecksPhase.id))
override def matches(sym1: Symbol, sym2: Symbol): Boolean =
atPhase(phase.next)(sym1.tpe =:= sym2.tpe)
}
while (opc.hasNext) {
if (!atPhase(currentRun.refchecksPhase.next)(
root.thisType.memberType(opc.overriding) matches
root.thisType.memberType(opc.overridden))) {
if (settings.debug.value)
log("" + opc.overriding.locationString + " " +
opc.overriding.infosString +
opc.overridden.locationString + " " +
opc.overridden.infosString)
doubleDefError(opc.overriding, opc.overridden)
}
opc.next
}
}
/*
for (bc <- root.info.baseClasses.tail; other <- bc.info.decls.toList) {
if (other.isTerm && !other.isConstructor && !(other hasFlag (PRIVATE | BRIDGE))) {
for (member <- root.info.nonPrivateMember(other.name).alternatives) {
if (member != other &&
!(member hasFlag BRIDGE) &&
atPhase(phase.next)(member.tpe =:= other.tpe) &&
!atPhase(refchecksPhase.next)(
root.thisType.memberType(member) matches root.thisType.memberType(other))) {
if (settings.debug.value) log("" + member.locationString + " " + member.infosString + other.locationString + " " + other.infosString);
doubleDefError(member, other)
}
}
}
}
*/
/** <p>
* Add bridge definitions to a template. This means:
* </p>
* <p>
* If there is a concrete member <code>m</code> which overrides a
* member in a base class of the template, and the erased types of
* the two members differ, and the two members are not inherited or
* defined by some parent class of the template, then a bridge from
* the overridden member <code>m1</code> to the member <code>m0</code>
* is added. The bridge has the erased type of <code>m1</code> and
* forwards to <code>m0</code>.
* </p>
* <p>
* No bridge is added if there is already a bridge to <code>m0</code>
* with the erased type of <code>m1</code> in the template.
* </p>
*/
private def bridgeDefs(owner: Symbol): (List[Tree], Set[Symbol]) = {
var toBeRemoved: Set[Symbol] = Set()
//println("computing bridges for " + owner)//DEBUG
assert(phase == currentRun.erasurePhase)
val site = owner.thisType
val bridgesScope = newScope
val bridgeTarget = new HashMap[Symbol, Symbol]
var bridges: List[Tree] = List()
val opc = atPhase(currentRun.explicitOuterPhase) {
new overridingPairs.Cursor(owner) {
override def parents: List[Type] = List(owner.info.parents.head)
override def exclude(sym: Symbol): Boolean =
!sym.isMethod || sym.hasFlag(PRIVATE) || super.exclude(sym)
}
}
while (opc.hasNext) {
val member = opc.overriding
val other = opc.overridden
//Console.println("bridge? " + member + ":" + member.tpe + member.locationString + " to " + other + ":" + other.tpe + other.locationString);//DEBUG
if (atPhase(currentRun.explicitOuterPhase)(!member.isDeferred)) {
val otpe = erasure(other.tpe);
val bridgeNeeded = atPhase(phase.next) (
!(other.tpe =:= member.tpe) &&
!(deconstMap(other.tpe) =:= deconstMap(member.tpe)) &&
{ var e = bridgesScope.lookupEntry(member.name)
while ((e ne null) && !((e.sym.tpe =:= otpe) && (bridgeTarget(e.sym) == member)))
e = bridgesScope.lookupNextEntry(e);
(e eq null)
}
);
if (bridgeNeeded) {
val bridge = other.cloneSymbolImpl(owner)
.setPos(owner.pos)
.setFlag(member.flags | BRIDGE)
.resetFlag(ACCESSOR | DEFERRED | LAZY | lateDEFERRED)
// the parameter symbols need to have the new owner
bridge.setInfo(otpe.cloneInfo(bridge))
bridgeTarget(bridge) = member
atPhase(phase.next) { owner.info.decls.enter(bridge) }
if (other.owner == owner) {
//println("bridge to same: "+other+other.locationString)//DEBUG
atPhase(phase.next) { owner.info.decls.unlink(other) }
toBeRemoved += other
}
bridgesScope enter bridge
bridges =
atPhase(phase.next) {
atPos(bridge.pos) {
val bridgeDef =
DefDef(bridge,
member.tpe match {
case MethodType(List(), ConstantType(c)) => Literal(c)
case _ =>
(((Select(This(owner), member): Tree) /: bridge.paramss)
((fun, vparams) => Apply(fun, vparams map Ident)))
});
if (settings.debug.value)
log("generating bridge from " + other + "(" + Flags.flagsToString(bridge.flags) + ")" + ":" + otpe + other.locationString + " to " + member + ":" + erasure(member.tpe) + member.locationString + " =\n " + bridgeDef);
bridgeDef
}
} :: bridges;
}
}
opc.next
}
(bridges, toBeRemoved)
}
/*
for (bc <- site.baseClasses.tail; other <- bc.info.decls.toList) {
if (other.isMethod && !other.isConstructor) {
for (member <- site.nonPrivateMember(other.name).alternatives) {
if (member != other &&
!(member hasFlag DEFERRED) &&
(site.memberType(member) matches site.memberType(other)) &&
!(site.parents exists (p =>
(p.symbol isSubClass member.owner) && (p.symbol isSubClass other.owner)))) {
...
}
}
*/
def addBridges(stats: List[Tree], base: Symbol): List[Tree] =
if (base.isTrait) stats
else {
val (bridges, toBeRemoved) = bridgeDefs(base)
if (bridges.isEmpty) stats
else (stats filterNot (stat => toBeRemoved contains stat.symbol)) ::: bridges
}
/** <p>
* Transform tree at phase <code>erasure</code> before retyping it.
* This entails the following:
* </p>
* <ul>
* <li>Remove all type parameters in class and method definitions.</li>
* <li>Remove all abstract and alias type definitions.</li>
* <li>
* Remove all type applications other than those involving a type
* test or cast.
* </li>
* <li>
* Remove all empty trees in statements and definitions in a
* <code>PackageDef</code>.
* </li>
* <li>Check that there are no double definitions in a template.</li>
* <li>Add bridge definitions to a template.</li>
* <li>
* Replace all types in type nodes and the <code>EmptyTree</code>
* object by their erasure. Type nodes of type <code>Unit</code>
* representing result types of methods are left alone.
* </li>
* <li>
* Reset all other type attributes to <code>null</code>, thus
* enforcing a retyping.
* </li>
* </ul>
*/
private val preTransformer = new Transformer {
override def transform(tree: Tree): Tree = {
if (tree.symbol == ArrayClass && !tree.isType) return tree // !!! needed?
val tree1 = tree match {
case ClassDef(mods, name, tparams, impl) =>
if (settings.debug.value)
log("defs of " + tree.symbol + " = " + tree.symbol.info.decls)
treeCopy.ClassDef(tree, mods, name, List(), impl)
case DefDef(mods, name, tparams, vparamss, tpt, rhs) =>
treeCopy.DefDef(tree, mods, name, List(), vparamss, tpt, rhs)
case TypeDef(_, _, _, _) =>
EmptyTree
case TypeApply(fun, args @ List(arg)) // !!! todo: simplify by having GenericArray also extract trees
if ((fun.symbol == Any_isInstanceOf || fun.symbol == Object_isInstanceOf) &&
unboundedGenericArrayLevel(arg.tpe) > 0) =>
val level = unboundedGenericArrayLevel(arg.tpe)
def isArrayTest(arg: Tree) =
gen.mkRuntimeCall("isArray", List(arg, Literal(Constant(level))))
typedPos(tree.pos) {
if (level == 1) isArrayTest(fun)
else
gen.evalOnce(fun, currentOwner, unit) { fun1 =>
gen.mkAnd(
treeCopy.TypeApply(tree, fun1(), args),
isArrayTest(fun1()))
}
}
case TypeApply(fun, args) if (fun.symbol.owner != AnyClass &&
fun.symbol != Object_asInstanceOf &&
fun.symbol != Object_isInstanceOf) =>
// leave all other type tests/type casts, remove all other type applications
fun
case Apply(fn @ Select(qual, name), args)
if (fn.symbol.owner == ArrayClass && (unboundedGenericArrayLevel(qual.tpe.widen) == 1)) =>
// convert calls to apply/update/length on generic arrays to
// calls of ScalaRunTime.array_xxx method calls
typedPos(tree.pos) { gen.mkRuntimeCall("array_"+name, qual :: args) }
case Apply(fn, args) =>
if (fn.symbol == Any_asInstanceOf)
fn match {
case TypeApply(Select(qual, _), List(targ)) =>
if (qual.tpe <:< targ.tpe) {
atPos(tree.pos) { Typed(qual, TypeTree(targ.tpe)) }
} else if (isNumericValueClass(qual.tpe.typeSymbol) &&
isNumericValueClass(targ.tpe.typeSymbol)) {
// convert numeric type casts
val cname = newTermName("to" + targ.tpe.typeSymbol.name)
val csym = qual.tpe.member(cname)
assert(csym != NoSymbol)
atPos(tree.pos) { Apply(Select(qual, csym), List()) }
} else
tree
}
// todo: also handle the case where the singleton type is buried in a compound
else if (fn.symbol == Any_isInstanceOf)
fn match {
case TypeApply(sel @ Select(qual, name), List(targ)) =>
def mkIsInstanceOf(q: () => Tree)(tp: Type): Tree =
Apply(
TypeApply(
Select(q(), Object_isInstanceOf) setPos sel.pos,
List(TypeTree(tp) setPos targ.pos)) setPos fn.pos,
List()) setPos tree.pos
targ.tpe match {
case SingleType(_, _) | ThisType(_) | SuperType(_, _) =>
val cmpOp = if (targ.tpe <:< AnyValClass.tpe) Any_equals else Object_eq
atPos(tree.pos) {
Apply(Select(qual, cmpOp), List(gen.mkAttributedQualifier(targ.tpe)))
}
case RefinedType(parents, decls) if (parents.length >= 2) =>
gen.evalOnce(qual, currentOwner, unit) { q =>
atPos(tree.pos) {
parents map mkIsInstanceOf(q) reduceRight gen.mkAnd
}
}
case _ =>
tree
}
case _ => tree
}
else {
def doDynamic(fn: Tree, qual: Tree): Tree = {
if (fn.symbol.owner.isRefinementClass && fn.symbol.allOverriddenSymbols.isEmpty)
ApplyDynamic(qual, args) setSymbol fn.symbol setPos tree.pos
else tree
}
fn match {
case Select(qual, _) => doDynamic(fn, qual)
case TypeApply(fni@Select(qual, _), _) => doDynamic(fni, qual)// type parameters are irrelevant in case of dynamic call
case _ =>
tree
}
}
case Select(_, _) =>
if (tree.symbol.owner.isRefinementClass) {
val overridden = tree.symbol.allOverriddenSymbols
assert(!overridden.isEmpty, tree.symbol)
tree.symbol = overridden.head
}
tree
case Template(parents, self, body) =>
assert(!currentOwner.isImplClass)
//Console.println("checking no dble defs " + tree)//DEBUG
checkNoDoubleDefs(tree.symbol.owner)
treeCopy.Template(tree, parents, emptyValDef, addBridges(body, currentOwner))
case Match(selector, cases) =>
Match(Typed(selector, TypeTree(selector.tpe)), cases)
case Literal(ct) if ct.tag == ClassTag
&& ct.typeValue.typeSymbol != definitions.UnitClass =>
treeCopy.Literal(tree, Constant(erasure(ct.typeValue)))
case _ =>
tree
}
tree1 match {
case EmptyTree | TypeTree() =>
tree1 setType erasure(tree1.tpe)
case DefDef(mods, name, tparams, vparamss, tpt, rhs) =>
val result = super.transform(tree1) setType null
tpt.tpe = erasure(tree.symbol.tpe).resultType
result
case _ =>
case class MyError(count : Int, ex : AssertionError) extends Error(ex.getMessage)
try {
super.transform(tree1) setType null
} catch {
case e @ MyError(n, ex) if n > 5 => throw e
case MyError(n,ex) =>
Console.println(tree1)
throw MyError(n + 1, ex)
// case ex : AssertionError =>
// Console.println(tree1)
// throw MyError(0, ex)
// case ex => throw ex
}
}
}
}
/** The main transform function: Pretransfom the tree, and then
* re-type it at phase erasure.next.
*/
override def transform(tree: Tree): Tree = {
val tree1 = preTransformer.transform(tree)
atPhase(phase.next) {
val tree2 = mixinTransformer.transform(tree1)
if (settings.debug.value) log("tree after addinterfaces: \n" + tree2)
newTyper(rootContext(unit, tree, true)).typed(tree2)
}
}
}
}
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