/
Erasure.scala
1428 lines (1297 loc) · 64.9 KB
/
Erasure.scala
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/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala.tools.nsc
package transform
import scala.reflect.internal.ClassfileConstants._
import scala.collection.{ mutable, immutable }
import symtab._
import Flags._
import scala.reflect.internal.Mode._
abstract class Erasure extends InfoTransform
with scala.reflect.internal.transform.Erasure
with typechecker.Analyzer
with TypingTransformers
with ast.TreeDSL
with TypeAdaptingTransformer
{
import global._
import definitions._
import CODE._
val phaseName: String = "erasure"
val requiredDirectInterfaces = perRunCaches.newAnyRefMap[Symbol, mutable.Set[Symbol]]()
def newTransformer(unit: CompilationUnit): Transformer =
new ErasureTransformer(unit)
override def keepsTypeParams = false
// -------- erasure on types --------------------------------------------------------
// convert a numeric with a toXXX method
def numericConversion(tree: Tree, numericSym: Symbol): Tree = {
val mname = newTermName("to" + numericSym.name)
val conversion = tree.tpe member mname
assert(conversion != NoSymbol, tree + " => " + numericSym)
atPos(tree.pos)(Apply(Select(tree, conversion), Nil))
}
private object NeedsSigCollector {
private val NeedsSigCollector_true = new NeedsSigCollector(true)
private val NeedsSigCollector_false = new NeedsSigCollector(false)
def apply(isClassConstructor: Boolean) = if (isClassConstructor) NeedsSigCollector_true else NeedsSigCollector_false
}
private class NeedsSigCollector(isClassConstructor: Boolean) extends TypeCollector(false) {
def traverse(tp: Type): Unit =
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.isExistentiallyBound || !args.isEmpty) result = true
else if (sym.isClass) traverse(rebindInnerClass(pre, sym)) // #2585
else if (!sym.isTopLevel) traverse(pre)
case PolyType(_, _) | ExistentialType(_, _) =>
result = true
case RefinedType(parents, _) =>
parents foreach traverse
case ClassInfoType(parents, _, _) =>
parents foreach traverse
case AnnotatedType(_, atp) =>
traverse(atp)
case MethodType(params, resultType) =>
if (isClassConstructor) {
val sigParams = params match {
case head :: tail if head.isOuterParam => tail
case _ => params
}
mapOver(sigParams)
// skip the result type, it is Void in the signature.
} else {
mapOver(tp)
}
case _ =>
mapOver(tp)
}
}
}
override protected def verifyJavaErasure = settings.Xverify || settings.isDebug
private def needsJavaSig(sym: Symbol, tp: Type, throwsArgs: List[Type]) = !settings.Ynogenericsig && {
def needs(tp: Type) = NeedsSigCollector(sym.isClassConstructor).collect(tp)
needs(tp) || throwsArgs.exists(needs)
}
// only refer to type params that will actually make it into the sig, this excludes:
// * higher-order type parameters
// * type parameters appearing in method parameters
// * type members not visible in an enclosing template
private def isTypeParameterInSig(sym: Symbol, initialSymbol: Symbol) = (
!sym.isHigherOrderTypeParameter &&
sym.isTypeParameterOrSkolem && (
(initialSymbol.enclClassChain.exists(sym isNestedIn _)) ||
(initialSymbol.isMethod && initialSymbol.typeParams.contains(sym))
)
)
/** This object is only used for sanity testing when -check:genjvm is set.
* In that case we make sure that the erasure of the `normalized` type
* is the same as the erased type that's generated. Normalization means
* unboxing some primitive types and further simplifications as they are done in jsig.
*/
val prepareSigMap = new TypeMap {
def squashBoxed(tp: Type): Type = tp.dealiasWiden match {
case t @ RefinedType(parents, decls) =>
val parents1 = parents mapConserve squashBoxed
if (parents1 eq parents) tp
else RefinedType(parents1, decls)
case t @ ExistentialType(tparams, tpe) =>
val tpe1 = squashBoxed(tpe)
if (tpe1 eq tpe) t
else ExistentialType(tparams, tpe1)
case t =>
if (boxedClass contains t.typeSymbol) ObjectTpe
else tp
}
def apply(tp: Type): Type = tp.dealiasWiden match {
case tp1 @ TypeBounds(lo, hi) =>
val lo1 = squashBoxed(apply(lo))
val hi1 = squashBoxed(apply(hi))
if ((lo1 eq lo) && (hi1 eq hi)) tp1
else TypeBounds(lo1, hi1)
case tp1 @ TypeRef(pre, sym, args) =>
def argApply(tp: Type) = {
val tp1 = apply(tp)
if (tp1.typeSymbol == UnitClass) ObjectTpe
else squashBoxed(tp1)
}
if (sym == ArrayClass && args.nonEmpty)
if (unboundedGenericArrayLevel(tp1) == 1) ObjectTpe
else mapOver(tp1)
else if (sym == AnyClass || sym == AnyValClass || sym == SingletonClass)
ObjectTpe
else if (sym == UnitClass)
BoxedUnitTpe
else if (sym == NothingClass)
RuntimeNothingClass.tpe
else if (sym == NullClass)
RuntimeNullClass.tpe
else {
val pre1 = apply(pre)
val args1 = args mapConserve argApply
if ((pre1 eq pre) && (args1 eq args)) tp1
else TypeRef(pre1, sym, args1)
}
case tp1 @ MethodType(params, restpe) =>
val params1 = mapOver(params)
val restpe1 = if (restpe.typeSymbol == UnitClass) UnitTpe else apply(restpe)
if ((params1 eq params) && (restpe1 eq restpe)) tp1
else MethodType(params1, restpe1)
case tp1 @ RefinedType(parents, decls) =>
val parents1 = parents mapConserve apply
if (parents1 eq parents) tp1
else RefinedType(parents1, decls)
case t @ ExistentialType(tparams, tpe) =>
val tpe1 = apply(tpe)
if (tpe1 eq tpe) t
else ExistentialType(tparams, tpe1)
case tp1: ClassInfoType =>
tp1
case tp1 =>
mapOver(tp1)
}
}
private def hiBounds(bounds: TypeBounds): List[Type] = bounds.hi.dealiasWiden match {
case RefinedType(parents, _) => parents map (_.dealiasWiden)
case tp => tp :: Nil
}
private def isErasedValueType(tpe: Type) = tpe.isInstanceOf[ErasedValueType]
/* Drop redundant types (ones which are implemented by some other parent) from the immediate parents.
* This is important on Android because there is otherwise an interface explosion.
*/
def minimizeParents(cls: Symbol, parents: List[Type]): List[Type] = if (parents.isEmpty) parents else {
val requiredDirect: Symbol => Boolean = requiredDirectInterfaces.getOrElse(cls, Set.empty)
var rest = parents.tail
var leaves = collection.mutable.ListBuffer.empty[Type] += parents.head
while (rest.nonEmpty) {
val candidate = rest.head
val candidateSym = candidate.typeSymbol
val required = requiredDirect(candidateSym) || !leaves.exists(t => t.typeSymbol isSubClass candidateSym)
if (required) {
leaves = leaves filter { t =>
val ts = t.typeSymbol
requiredDirect(ts) || !ts.isTraitOrInterface || !candidateSym.isSubClass(ts)
}
leaves += candidate
}
rest = rest.tail
}
leaves.toList
}
/** The Java signature of type 'info', for symbol sym. The symbol is used to give the right return
* type for constructors.
*/
final def javaSig(sym0: Symbol, info: Type, markClassUsed: Symbol => Unit): Option[String] = enteringErasure { javaSig0(sym0, info, markClassUsed) }
@noinline
private final def javaSig0(sym0: Symbol, info: Type, markClassUsed: Symbol => Unit): Option[String] = {
val builder = new java.lang.StringBuilder(64)
val isTraitSignature = sym0.enclClass.isTrait
def superSig(cls: Symbol, parents: List[Type]): Unit = {
def isInterfaceOrTrait(sym: Symbol) = sym.isInterface || sym.isTrait
// a signature should always start with a class
def ensureClassAsFirstParent(tps: List[Type]) = tps match {
case Nil => ObjectTpe :: Nil
case head :: tail if isInterfaceOrTrait(head.typeSymbol) => ObjectTpe :: tps
case _ => tps
}
val minParents = minimizeParents(cls, parents)
val validParents =
if (isTraitSignature)
// java is unthrilled about seeing interfaces inherit from classes
minParents filter (p => isInterfaceOrTrait(p.typeSymbol))
else minParents
val ps = ensureClassAsFirstParent(validParents)
ps.foreach(boxedSig)
}
def boxedSig(tp: Type): Unit = jsig(tp, unboxedVCs = false)
def boundsSig(bounds: List[Type]): Unit = {
val (isTrait, isClass) = bounds partition (_.typeSymbol.isTrait)
isClass match {
case Nil => builder.append(':') // + boxedSig(ObjectTpe)
case x :: _ => builder.append(':'); boxedSig(x)
}
isTrait.foreach { tp =>
builder.append(':')
boxedSig(tp)
}
}
def paramSig(tsym: Symbol): Unit = {
builder.append(tsym.name)
boundsSig(hiBounds(tsym.info.bounds))
}
def polyParamSig(tparams: List[Symbol]): Unit = (
if (!tparams.isEmpty) {
builder.append('<')
tparams foreach paramSig
builder.append('>')
}
)
// Anything which could conceivably be a module (i.e. isn't known to be
// a type parameter or similar) must go through here or the signature is
// likely to end up with Foo<T>.Empty where it needs Foo<T>.Empty$.
def fullNameInSig(sym: Symbol): Unit = builder.append('L').append(enteringJVM(sym.javaBinaryNameString))
@noinline
def jsig(tp0: Type, existentiallyBound: List[Symbol] = Nil, toplevel: Boolean = false, unboxedVCs: Boolean = true): Unit = {
val tp = tp0.dealias
tp match {
case st: SubType =>
jsig(st.supertype, existentiallyBound, toplevel, unboxedVCs)
case ExistentialType(tparams, tpe) =>
jsig(tpe, tparams, toplevel, unboxedVCs)
case TypeRef(pre, sym, args) =>
def argSig(tp: Type): Unit =
if (existentiallyBound contains tp.typeSymbol) {
val bounds = tp.typeSymbol.info.bounds
if (!(AnyRefTpe <:< bounds.hi)) {
builder.append('+')
boxedSig(bounds.hi)
}
else if (!(bounds.lo <:< NullTpe)) {
builder.append('-')
boxedSig(bounds.lo)
}
else builder.append('*')
} else tp match {
case PolyType(_, res) =>
builder.append('*') // scala/bug#7932
case _ =>
boxedSig(tp)
}
def classSig: Unit = {
markClassUsed(sym)
val preRebound = pre.baseType(sym.owner) // #2585
if (needsJavaSig(sym, preRebound, Nil)) {
val i = builder.length()
jsig(preRebound, existentiallyBound)
if (builder.charAt(i) == 'L') {
builder.delete(builder.length() - 1, builder.length())// delete ';'
// If the prefix is a module, drop the '$'. Classes (or modules) nested in modules
// are separated by a single '$' in the filename: `object o { object i }` is o$i$.
if (preRebound.typeSymbol.isModuleClass)
builder.delete(builder.length() - 1, builder.length())
// Ensure every '.' in the generated signature immediately follows
// a close angle bracket '>'. Any which do not are replaced with '$'.
// This arises due to multiply nested classes in the face of the
// rewriting explained at rebindInnerClass.
// TODO revisit this. Does it align with javac for code that can be expressed in both languages?
val delimiter = if (builder.charAt(builder.length() - 1) == '>') '.' else '$'
builder.append(delimiter).append(sym.javaSimpleName)
} else fullNameInSig(sym)
} else fullNameInSig(sym)
if (!args.isEmpty) {
builder.append('<')
args foreach argSig
builder.append('>')
}
builder.append(';')
}
// If args isEmpty, Array is being used as a type constructor
if (sym == ArrayClass && args.nonEmpty) {
if (unboundedGenericArrayLevel(tp) == 1) jsig(ObjectTpe)
else {
builder.append(ARRAY_TAG)
args.foreach(jsig(_))
}
}
else if (isTypeParameterInSig(sym, sym0)) {
assert(!sym.isAliasType, "Unexpected alias type: " + sym)
builder.append(TVAR_TAG).append(sym.name).append(';')
}
else if (sym == AnyClass || sym == AnyValClass || sym == SingletonClass)
jsig(ObjectTpe)
else if (sym == UnitClass)
jsig(BoxedUnitTpe)
else if (sym == NothingClass)
jsig(RuntimeNothingClass.tpe)
else if (sym == NullClass)
jsig(RuntimeNullClass.tpe)
else if (isPrimitiveValueClass(sym)) {
if (!unboxedVCs) jsig(ObjectTpe)
else if (sym == UnitClass) jsig(BoxedUnitTpe)
else builder.append(abbrvTag(sym))
}
else if (sym.isDerivedValueClass) {
if (unboxedVCs) {
val unboxedSeen = (tp memberType sym.derivedValueClassUnbox).finalResultType
jsig(unboxedSeen, existentiallyBound, toplevel)
} else classSig
}
else if (sym.isClass)
classSig
else
jsig(erasure(sym0)(tp), existentiallyBound, toplevel, unboxedVCs)
case PolyType(tparams, restpe) =>
assert(tparams.nonEmpty)
if (toplevel) polyParamSig(tparams)
jsig(restpe)
case MethodType(params, restpe) =>
builder.append('(')
params foreach (p => {
val isClassOuterParam = sym0.isClassConstructor && p.isOuterParam
if (!isClassOuterParam) {
val tp = p.attachments.get[TypeParamVarargsAttachment] match {
case Some(att) =>
// For @varargs forwarders, a T* parameter has type Array[Object] in the forwarder
// instead of Array[T], as the latter would erase to Object (instead of Array[Object]).
// To make the generic signature correct ("[T", not "[Object"), an attachment on the
// parameter symbol stores the type T that was replaced by Object.
builder.append('['); att.typeParamRef
case _ => p.tpe
}
jsig(tp)
}
})
builder.append(')')
if (restpe.typeSymbol == UnitClass || sym0.isConstructor) builder.append(VOID_TAG) else jsig(restpe)
case RefinedType(parents, decls) =>
jsig(intersectionDominator(parents), unboxedVCs = unboxedVCs)
case ClassInfoType(parents, _, _) =>
superSig(tp.typeSymbol, parents)
case AnnotatedType(_, atp) =>
jsig(atp, existentiallyBound, toplevel, unboxedVCs)
case BoundedWildcardType(bounds) =>
println("something's wrong: "+sym0+":"+sym0.tpe+" has a bounded wildcard type")
jsig(bounds.hi, existentiallyBound, toplevel, unboxedVCs)
case _ =>
val etp = erasure(sym0)(tp)
if (etp eq tp) throw new UnknownSig
else jsig(etp)
}
}
val throwsArgs = sym0.annotations flatMap ThrownException.unapply
if (needsJavaSig(sym0, info, throwsArgs)) {
try {
jsig(info, toplevel = true)
throwsArgs.foreach { t =>
builder.append('^')
jsig(t, toplevel = true)
}
Some(builder.toString)
}
catch { case ex: UnknownSig => None }
}
else None
}
class UnknownSig extends Exception
/** Add calls to supermixin constructors
* `super[mix].$init$()`
* to tree, which is assumed to be the body of a constructor of class clazz.
*/
private def addMixinConstructorCalls(tree: Tree, clazz: Symbol): Tree = {
// TODO: move to constructors?
def mixinConstructorCalls: List[Tree] = {
for (mc <- clazz.mixinClasses.reverse if mc.isTrait && mc.primaryConstructor != NoSymbol)
yield atPos(tree.pos) {
Apply(SuperSelect(clazz, mc.primaryConstructor), Nil)
}
}
tree match {
case Block(Nil, expr) =>
// AnyVal constructor - have to provide a real body so the
// jvm doesn't throw a VerifyError. But we can't add the
// body until now, because the typer knows that Any has no
// constructor and won't accept a call to super.init.
assert((clazz isSubClass AnyValClass) || clazz.info.parents.isEmpty, clazz)
Block(List(Apply(gen.mkSuperInitCall, Nil)), expr)
case Block(stats, expr) =>
// needs `hasSymbolField` check because `supercall` could be a block (named / default args)
val (presuper, supercall :: rest) = stats span (t => t.hasSymbolWhich(_ hasFlag PRESUPER))
treeCopy.Block(tree, presuper ::: (supercall :: mixinConstructorCalls ::: rest), expr)
}
}
val deconstMap = new TypeMap {
// For some reason classOf[Foo] creates ConstantType(Constant(tpe)) with an actual Type for tpe,
// which is later translated to a Class. Unfortunately that means we have bugs like the erasure
// of Class[Foo] and classOf[Bar] not being seen as equivalent, leading to duplicate method
// generation and failing bytecode. See ticket #4753.
def apply(tp: Type): Type = tp match {
case PolyType(_, _) => mapOver(tp)
case MethodType(_, _) => mapOver(tp) // nullarymethod was eliminated during uncurry
case ConstantType(Constant(_: Type)) => ClassClass.tpe // all classOfs erase to Class
case _ => tp.deconst
}
}
// ## requires a little translation
private lazy val poundPoundMethods = Set[Symbol](Any_##, Object_##)
// Methods on Any/Object which we rewrite here while we still know what
// is a primitive and what arrived boxed.
private lazy val interceptedMethods = poundPoundMethods ++ primitiveGetClassMethods
// -------- erasure on trees ------------------------------------------
override def newTyper(context: Context) = new Eraser(context)
class EnterBridges(unit: CompilationUnit, root: Symbol) {
class BridgesCursor(root: Symbol) extends overridingPairs.Cursor(root) {
override def parents = root.info.firstParent :: Nil
// Varargs bridges may need generic bridges due to the non-repeated part of the signature of the involved methods.
// The vararg bridge is generated during refchecks (probably to simplify override checking),
// but then the resulting varargs "bridge" method may itself need an actual erasure bridge.
// TODO: like javac, generate just one bridge method that wraps Seq <-> varargs and does erasure-induced casts
override def exclude(sym: Symbol) = !sym.isMethod || super.exclude(sym)
}
val site = root.thisType
val bridgesScope = newScope
val bridgeTarget = mutable.HashMap[Symbol, Symbol]()
val opc = enteringExplicitOuter { new BridgesCursor(root) }
def computeAndEnter(): Unit = {
while (opc.hasNext) {
if (enteringExplicitOuter(!opc.low.isDeferred))
checkPair(opc. currentPair)
opc.next()
}
}
/** Check that a bridge only overrides members that are also overridden by the original member.
* This test is necessary only for members that have a value class in their type.
* Such members are special because their types after erasure and after post-erasure differ/.
* This means we generate them after erasure, but the post-erasure transform might introduce
* a name clash. The present method guards against these name clashes.
*
* @param member The original member
* @param other The overridden symbol for which the bridge was generated
* @param bridge The bridge
*/
def checkBridgeOverrides(member: Symbol, other: Symbol, bridge: Symbol): Seq[(Position, String)] = {
def fulldef(sym: Symbol) =
if (sym == NoSymbol) sym.toString
else s"$sym: ${sym.tpe} in ${sym.owner}"
val clashErrors = mutable.Buffer[(Position, String)]()
def clashError(what: String) = {
val pos = if (member.owner == root) member.pos else root.pos
val msg = sm"""bridge generated for member ${fulldef(member)}
|which overrides ${fulldef(other)}
|clashes with definition of $what;
|both have erased type ${exitingPostErasure(bridge.tpe)}"""
clashErrors += Tuple2(pos, msg)
}
for (bc <- root.baseClasses) {
if (settings.isDebug)
exitingPostErasure(println(
sm"""check bridge overrides in $bc
|${bc.info.nonPrivateDecl(bridge.name)}
|${site.memberType(bridge)}
|${site.memberType(bc.info.nonPrivateDecl(bridge.name) orElse IntClass)}
|${(bridge.matchingSymbol(bc, site))}"""))
def overriddenBy(sym: Symbol) =
sym.matchingSymbol(bc, site).alternatives filter (sym => !sym.isBridge)
for (overBridge <- exitingPostErasure(overriddenBy(bridge))) {
if (overBridge == member) {
clashError("the member itself")
} else {
val overMembers = overriddenBy(member)
if (!overMembers.exists(overMember =>
exitingPostErasure(overMember.tpe =:= overBridge.tpe))) {
clashError(fulldef(overBridge))
}
}
}
}
clashErrors
}
/** TODO - work through this logic with a fine-toothed comb, incorporating
* into SymbolPairs where appropriate.
*/
def checkPair(pair: SymbolPair) {
import pair._
val member = low
val other = high
val otpe = highErased
val bridgeNeeded = exitingErasure (
!member.isMacro &&
!(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)
return
var newFlags = (member.flags | BRIDGE | ARTIFACT) & ~(ACCESSOR | DEFERRED | LAZY)
// If `member` is a ModuleSymbol, the bridge should not also be a ModuleSymbol. Otherwise we
// end up with two module symbols with the same name in the same scope, which is surprising
// when implementing later phases.
if (member.isModule) newFlags = (newFlags | METHOD) & ~(MODULE | STABLE)
val bridge = other.cloneSymbolImpl(root, newFlags).setPos(root.pos).setAnnotations(member.annotations)
debuglog("generating bridge from %s (%s): %s to %s: %s".format(
other, flagsToString(newFlags),
otpe + other.locationString, member,
specialErasure(root)(member.tpe) + member.locationString)
)
// the parameter symbols need to have the new owner
bridge setInfo (otpe cloneInfo bridge)
bridgeTarget(bridge) = member
def sigContainsValueClass = (member.tpe exists (_.typeSymbol.isDerivedValueClass))
val shouldAdd = (
!sigContainsValueClass
|| (checkBridgeOverrides(member, other, bridge) match {
case Nil => true
case es if member.owner.isAnonymousClass => resolveAnonymousBridgeClash(member, bridge); true
case es => for ((pos, msg) <- es) reporter.error(pos, msg); false
})
)
if (shouldAdd) {
exitingErasure(root.info.decls enter bridge)
bridgesScope enter bridge
addBridge(bridge, member, other)
//bridges ::= makeBridgeDefDef(bridge, member, other)
}
}
protected def addBridge(bridge: Symbol, member: Symbol, other: Symbol) {} // hook for GenerateBridges
}
class GenerateBridges(unit: CompilationUnit, root: Symbol) extends EnterBridges(unit, root) {
var bridges = List.empty[Tree]
var toBeRemoved = immutable.Set.empty[Symbol]
def generate(): (List[Tree], immutable.Set[Symbol]) = {
super.computeAndEnter()
(bridges, toBeRemoved)
}
override def addBridge(bridge: Symbol, member: Symbol, other: Symbol): Unit = {
if (other.owner == root) {
exitingErasure(root.info.decls.unlink(other))
toBeRemoved += other
}
bridges ::= makeBridgeDefDef(bridge, member, other)
}
final def makeBridgeDefDef(bridge: Symbol, member: Symbol, other: Symbol) = exitingErasure {
// type checking ensures we can safely call `other`, but unless `member.tpe <:< other.tpe`,
// calling `member` is not guaranteed to succeed in general, there's
// nothing we can do about this, except for an unapply: when this subtype test fails,
// return None without calling `member`
//
// TODO: should we do this for user-defined unapplies as well?
// does the first argument list have exactly one argument -- for user-defined unapplies we can't be sure
def maybeWrap(bridgingCall: Tree): Tree = {
val guardExtractor = ( // can't statically know which member is going to be selected, so don't let this depend on member.isSynthetic
(member.name == nme.unapply || member.name == nme.unapplySeq)
&& !exitingErasure((member.tpe <:< other.tpe))) // no static guarantees (TODO: is the subtype test ever true?)
import CODE._
val _false = FALSE
val pt = member.tpe.resultType
lazy val zero =
if (_false.tpe <:< pt) _false
else if (NoneModule.tpe <:< pt) REF(NoneModule)
else EmptyTree
if (guardExtractor && (zero ne EmptyTree)) {
val typeTest = gen.mkIsInstanceOf(REF(bridge.firstParam), member.tpe.params.head.tpe)
IF (typeTest) THEN bridgingCall ELSE zero
} else bridgingCall
}
val rhs = member.tpe match {
case MethodType(Nil, ConstantType(c)) => Literal(c)
case _ =>
val sel: Tree = Select(This(root), member)
val bridgingCall = (sel /: bridge.paramss)((fun, vparams) => Apply(fun, vparams map Ident))
maybeWrap(bridgingCall)
}
DefDef(bridge, rhs)
}
}
/** The modifier typer which retypes with erased types. */
class Eraser(_context: Context) extends Typer(_context) {
val typeAdapter = new TypeAdapter { def typedPos(pos: Position)(tree: Tree): Tree = Eraser.this.typedPos(pos)(tree) }
import typeAdapter._
override protected def stabilize(tree: Tree, pre: Type, mode: Mode, pt: Type): Tree = tree
/** Replace member references as follows:
*
* - `x == y` for == in class Any becomes `x equals y` with equals in class Object.
* - `x != y` for != in class Any becomes `!(x equals y)` with equals in class Object.
* - x.asInstanceOf[T] becomes x.$asInstanceOf[T]
* - x.isInstanceOf[T] becomes x.$isInstanceOf[T]
* - x.isInstanceOf[ErasedValueType(tref)] becomes x.isInstanceOf[tref.sym.tpe]
* - x.m where m is some other member of Any becomes x.m where m is a member of class Object.
* - x.m where x has unboxed value type T and m is not a directly translated member of T becomes T.box(x).m
* - x.m where x is a reference type and m is a directly translated member of value type T becomes x.TValue().m
* - All forms of x.m where x is a boxed type and m is a member of an unboxed class become
* x.m where m is the corresponding member of the boxed class.
*/
private def adaptMember(tree: Tree): Tree = {
//Console.println("adaptMember: " + tree);
tree match {
case Apply(ta @ TypeApply(sel @ Select(qual, name), targ :: Nil), List())
if tree.symbol == Any_asInstanceOf =>
val qual1 = typedQualifier(qual, NOmode, ObjectTpe) // need to have an expected type, see #3037
// !!! Make pending/run/t5866b.scala work. The fix might be here and/or in unbox1.
if (isPrimitiveValueType(targ.tpe) || isErasedValueType(targ.tpe)) {
val noNullCheckNeeded = targ.tpe match {
case ErasedValueType(_, underlying) => isPrimitiveValueType(underlying)
case _ => true
}
if (noNullCheckNeeded) unbox(qual1, targ.tpe)
else {
val untyped =
// util.trace("new asinstanceof test") {
gen.evalOnce(qual1, context.owner, fresh) { qual =>
If(Apply(Select(qual(), nme.eq), List(Literal(Constant(null)) setType NullTpe)),
Literal(Constant(null)) setType targ.tpe,
unbox(qual(), targ.tpe))
}
// }
typed(untyped)
}
} else treeCopy.Apply(tree, treeCopy.TypeApply(ta, treeCopy.Select(sel, qual1, name), List(targ)), List())
case Apply(TypeApply(sel @ Select(qual, name), List(targ)), List())
if tree.symbol == Any_isInstanceOf =>
targ.tpe match {
case ErasedValueType(clazz, _) => targ.setType(clazz.tpe)
case _ =>
}
tree
case Select(qual, name) =>
if (tree.symbol == NoSymbol) {
tree
} else if (name == nme.CONSTRUCTOR) {
if (tree.symbol.owner == AnyValClass) tree.symbol = ObjectClass.primaryConstructor
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, tree.symbol.name))))
else {
var qual1 = typedQualifier(qual)
if ((isPrimitiveValueType(qual1.tpe) && !isPrimitiveValueMember(tree.symbol)) ||
isErasedValueType(qual1.tpe))
qual1 = box(qual1)
else if (!isPrimitiveValueType(qual1.tpe) && isPrimitiveValueMember(tree.symbol))
qual1 = unbox(qual1, tree.symbol.owner.tpe)
def selectFrom(qual: Tree) = treeCopy.Select(tree, qual, name)
if (isPrimitiveValueMember(tree.symbol) && !isPrimitiveValueType(qual1.tpe)) {
tree.symbol = NoSymbol
selectFrom(qual1)
} else if (isMethodTypeWithEmptyParams(qual1.tpe)) { // see also adaptToType in TypeAdapter
assert(qual1.symbol.isStable, qual1.symbol)
adaptMember(selectFrom(applyMethodWithEmptyParams(qual1)))
} else if (!qual1.isInstanceOf[Super] && (!isJvmAccessible(qual1.tpe.typeSymbol, context) || !qual1.tpe.typeSymbol.isSubClass(tree.symbol.owner))) {
// A selection requires a cast:
// - In `(foo: Option[String]).get.trim`, the qualifier has type `Object`. We cast
// to the owner of `trim` (`String`), unless the owner is a non-accessible Java
// class, in which case a `QualTypeSymAttachment` is present (see below).
// - In `a.b().c()`, the qualifier `a.b()` may have an accessible type `X` before
// erasure, but a non-accessible type `Y` after erasure (scala/bug#10450). Again
// we cast to the owner of `c`, or, if that is not accessible either, to the
// class stored in the `QualTypeSymAttachment`.
//
// A `QualTypeSymAttachment` is present if the selected member's owner is not an
// accessible (java-defined) class, see `preErase`.
//
// Selections from `super` are not handled here because inserting a cast would not be
// legal code. Instead there's a special case in `typedSelectInternal`.
val qualTpe = tree.getAndRemoveAttachment[QualTypeSymAttachment] match {
case Some(a) => a.sym.tpe
case None => tree.symbol.owner.tpe
}
selectFrom(cast(qual1, qualTpe))
} else {
selectFrom(qual1)
}
}
case SelectFromArray(qual, name, erasure) =>
var qual1 = typedQualifier(qual)
if (!(qual1.tpe <:< erasure)) qual1 = cast(qual1, erasure)
Select(qual1, name) copyAttrs tree
case _ =>
tree
}
}
/** A replacement for the standard typer's adapt method.
*/
override protected def adapt(tree: Tree, mode: Mode, pt: Type, original: Tree = EmptyTree): Tree =
adaptToType(tree, pt)
/** A replacement for the standard typer's `typed1` method.
*/
override def typed1(tree: Tree, mode: Mode, pt: Type): Tree = {
val tree1 = try {
tree match {
case DefDef(_,_,_,_,_,_) if tree.symbol.isClassConstructor && tree.symbol.isPrimaryConstructor && tree.symbol.owner != ArrayClass =>
super.typed1(deriveDefDef(tree)(addMixinConstructorCalls(_, tree.symbol.owner)), mode, pt) // (3)
case Template(parents, self, body) =>
val parents1 = tree.symbol.owner.info.parents map (t => TypeTree(t) setPos tree.pos)
super.typed1(treeCopy.Template(tree, parents1, noSelfType, body), mode, pt)
case InjectDerivedValue(arg) =>
(tree.attachments.get[TypeRefAttachment]: @unchecked) match {
case Some(itype) =>
val tref = itype.tpe
val argPt = enteringErasure(erasedValueClassArg(tref))
log(s"transforming inject $arg -> $tref/$argPt")
val result = typed(arg, mode, argPt)
log(s"transformed inject $arg -> $tref/$argPt = $result:${result.tpe}")
return result setType ErasedValueType(tref.sym, result.tpe)
}
case tree @ Block(_, _: LabelDef) =>
// Push adaptations out to the block to preserve patmat tree shapes.
// This helps the back-end to generate better code.
super.typed1(adaptMember(tree), mode, WildcardType)
case _ =>
super.typed1(adaptMember(tree), mode, pt)
}
} catch {
case er: TypeError =>
Console.println("exception when typing " + tree+"/"+tree.getClass)
Console.println(er.msg + " in file " + context.owner.sourceFile)
er.printStackTrace
abort("unrecoverable error")
case ex: Exception =>
//if (settings.debug.value)
try Console.println("exception when typing " + tree)
finally throw ex
throw ex
}
def adaptCase(cdef: CaseDef): CaseDef = {
val newCdef = deriveCaseDef(cdef)(adaptToType(_, tree1.tpe))
newCdef setType newCdef.body.tpe
}
def adaptBranch(branch: Tree): Tree =
if (branch == EmptyTree) branch else adaptToType(branch, tree1.tpe)
tree1 match {
case fun: Function =>
fun.attachments.get[SAMFunction] match {
case Some(SAMFunction(samTp, _, _)) => fun setType specialScalaErasure(samTp)
case _ => fun
}
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.isOverloaded) {
val first = tree1.symbol.alternatives.head
val firstTpe = first.tpe
val sym1 = tree1.symbol.filter {
alt => alt == first || !(firstTpe looselyMatches alt.tpe)
}
if (tree.symbol ne sym1) {
tree1 setSymbol sym1 setType sym1.tpe
}
}
tree1
case _ =>
tree1
}
}
}
/** The erasure transformer */
class ErasureTransformer(unit: CompilationUnit) extends Transformer {
import overridingPairs.Cursor
private def doubleDefError(pair: SymbolPair) {
import pair._
if (!pair.isErroneous) {
val what = (
if (low.owner == high.owner) "double definition"
else if (low.owner == base) "name clash between defined and inherited member"
else "name clash between inherited members"
)
val when = if (exitingRefchecks(lowType matches highType)) "" else " after erasure: " + exitingPostErasure(highType)
reporter.error(pos,
s"""|$what:
|${exitingRefchecks(highString)} and
|${exitingRefchecks(lowString)}
|have same type$when""".trim.stripMargin
)
}
low setInfo ErrorType
}
private def sameTypeAfterErasure(sym1: Symbol, sym2: Symbol) =
exitingPostErasure(sym1.info =:= sym2.info) && !sym1.isMacro && !sym2.isMacro
/** TODO - adapt SymbolPairs so it can be used here. */
private def checkNoDeclaredDoubleDefs(base: Symbol) {
val decls = base.info.decls
// scala/bug#8010 force infos, otherwise makeNotPrivate in ExplicitOuter info transformer can trigger
// a scope rehash while were iterating and we can see the same entry twice!
// Inspection of SymbolPairs (the basis of OverridingPairs), suggests that it is immune
// from this sort of bug as it copies the symbols into a temporary scope *before* any calls to `.info`,
// ie, no variant of it calls `info` or `tpe` in `SymbolPair#exclude`.
//
// Why not just create a temporary scope here? We need to force the name changes in any case before
// we do these checks, so that we're comparing same-named methods based on the expanded names that actually
// end up in the bytecode.
exitingPostErasure(decls.foreach(_.info))
var e = decls.elems
while (e ne null) {
if (e.sym.isTerm) {
var e1 = decls lookupNextEntry e
while (e1 ne null) {
assert(e.sym ne e1.sym, s"Internal error: encountered ${e.sym.debugLocationString} twice during scope traversal. This might be related to scala/bug#8010.")
if (sameTypeAfterErasure(e.sym, e1.sym))
doubleDefError(new SymbolPair(base, e.sym, e1.sym))
e1 = decls lookupNextEntry e1
}
}
e = e.next
}
}
private class DoubleDefsCursor(root: Symbol) extends Cursor(root) {
// specialized members have no type history before 'specialize', causing double def errors for curried defs
override def exclude(sym: Symbol): Boolean = (
sym.isType
|| super.exclude(sym)
|| !sym.hasTypeAt(currentRun.refchecksPhase.id)
)
override def matches(high: Symbol) = !high.isPrivate
}
/** Emit an error if there is a double definition. This can happen if:
*
* - A template defines two members with the same name and erased type.
* - A template defines and inherits two members `m` with different types,
* but their erased types are the same.
* - A template inherits two members `m` with different types,
* but their erased types are the same.
*/
private def checkNoDoubleDefs(root: Symbol) {
checkNoDeclaredDoubleDefs(root)
def isErasureDoubleDef(pair: SymbolPair) = {
import pair._
log(s"Considering for erasure clash:\n$pair")
!exitingRefchecks(lowType matches highType) && sameTypeAfterErasure(low, high)
}
(new DoubleDefsCursor(root)).iterator filter isErasureDoubleDef foreach doubleDefError
}
/** Add bridge definitions to a template. This means:
*
* If there is a concrete member `m` 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 `m1` to the
* member `m0` is added. The bridge has the erased type of `m1` and
* forwards to `m0`.
*
* No bridge is added if there is already a bridge to `m0` with the erased
* type of `m1` in the template.
*/
private def bridgeDefs(owner: Symbol): (List[Tree], immutable.Set[Symbol]) = {
assert(phase == currentRun.erasurePhase, phase)
new GenerateBridges(unit, owner).generate()
}
def addBridgesToTemplate(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
}
def addBridgesToLambda(lambdaClass: Symbol): Unit = {
assert(phase == currentRun.erasurePhase, phase)
assert(lambdaClass.isClass, lambdaClass)
new EnterBridges(unit, lambdaClass).computeAndEnter()
}
/** Transform tree at phase erasure before retyping it.
* This entails the following:
*
* - Remove all type parameters in class and method definitions.
* - Remove all abstract and alias type definitions.
* - Remove all type applications other than those involving a type test or cast.
* - Remove all empty trees in statements and definitions in a PackageDef.
* - Check that there are no double definitions in a template.
* - Add bridge definitions to a template.
* - Replace all types in type nodes and the EmptyTree object by their erasure.
* Type nodes of type Unit representing result types of methods are left alone.
* - Remove all instance creations new C(arg) where C is an inlined class.
* - Reset all other type attributes to null, thus enforcing a retyping.
*/
private val preTransformer = new TypingTransformer(unit) {
// Work around some incomplete path unification :( there are similar casts in SpecializeTypes
def context: Context = localTyper.context.asInstanceOf[Context]