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The treecheckers revealed that auxiliary constr...
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The treecheckers revealed that auxiliary constructors, which must follow
the primary at the source level, are reordered to precede the primary
during the constructors phase. Added some logic to preserve the original
ordering. Also tweaked treePrinters to not confusingly print object Foo
as "final class Foo". Review by moors.
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@paulp
paulp committed Oct 26, 2010
1 parent 2212fd6 commit 6b6d214
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Showing 2 changed files with 57 additions and 51 deletions.
23 changes: 16 additions & 7 deletions src/compiler/scala/tools/nsc/ast/TreePrinters.scala
View file
Expand Up @@ -95,15 +95,19 @@ trait TreePrinters { trees: SymbolTable =>
}
}

private def symFn[T](tree: Tree, f: Symbol => T, orElse: => T): T = tree.symbol match {
case null | NoSymbol => orElse
case sym => f(sym)
}
private def ifSym(tree: Tree, p: Symbol => Boolean) = symFn(tree, p, false)

private def symNameInternal(tree: Tree, name: Name, decoded: Boolean): String = {
val nameToString: Name => String = if (decoded) _.decode else _.toString

tree.symbol match {
case null | NoSymbol => nameToString(name)
case sym =>
val prefix = if (sym.isMixinConstructor) "/*%s*/".format(nameToString(sym.owner.name)) else ""
prefix + tree.symbol.nameString
def nameFn(sym: Symbol) = {
val prefix = if (sym.isMixinConstructor) "/*%s*/".format(nameToString(sym.owner.name)) else ""
prefix + tree.symbol.nameString
}
symFn(tree, nameFn, nameToString(name))
}

def decodedSymName(tree: Tree, name: Name) = symNameInternal(tree, name, true)
Expand Down Expand Up @@ -149,7 +153,12 @@ trait TreePrinters { trees: SymbolTable =>
case ClassDef(mods, name, tparams, impl) =>
printAnnotations(tree)
printModifiers(tree, mods)
print((if (mods hasFlag TRAIT) "trait " else "class ") + symName(tree, name))
val word =
if (mods.isTrait) "trait"
else if (ifSym(tree, _.isModuleClass)) "object"
else "class"

print(word + " " + symName(tree, name))
printTypeParams(tparams)
print(if (mods.isDeferred) " <: " else " extends "); print(impl) // (part of DEVIRTUALIZE)

Expand Down
85 changes: 41 additions & 44 deletions src/compiler/scala/tools/nsc/transform/Constructors.scala
View file
Expand Up @@ -37,23 +37,20 @@ abstract class Constructors extends Transform with ast.TreeDSL {
val specializedFlag: Symbol = clazz.info.decl(nme.SPECIALIZED_INSTANCE)
val shouldGuard = (specializedFlag != NoSymbol) && !clazz.hasFlag(SPECIALIZED)

var constr: DefDef = null // The primary constructor
var constrParams: List[Symbol] = null // ... and its parameters
var constrBody: Block = null // ... and its body

case class ConstrInfo(
constr: DefDef, // The primary constructor
constrParams: List[Symbol], // ... and its parameters
constrBody: Block // ... and its body
)
// decompose primary constructor into the three entities above.
for (stat <- stats) {
stat match {
case ddef @ DefDef(_, _, _, List(vparams), _, rhs @ Block(_, Literal(_))) =>
if (ddef.symbol.isPrimaryConstructor) {
constr = ddef
constrParams = vparams map (_.symbol)
constrBody = rhs
}
case _ =>
}
val constrInfo: ConstrInfo = {
val primary = stats find (_.symbol.isPrimaryConstructor)
assert(primary.isDefined, "no constructor in template: impl = " + impl)

val ddef @ DefDef(_, _, _, List(vparams), _, rhs @ Block(_, _)) = primary.get
ConstrInfo(ddef, vparams map (_.symbol), rhs)
}
assert((constr ne null) && (constrBody ne null), impl)
import constrInfo._

// The parameter accessor fields which are members of the class
val paramAccessors = clazz.constrParamAccessors
Expand All @@ -65,12 +62,12 @@ abstract class Constructors extends Transform with ast.TreeDSL {
// The constructor parameter with given name. This means the parameter
// has given name, or starts with given name, and continues with a `$' afterwards.
def parameterNamed(name: Name): Symbol = {
def matchesName(param: Symbol) =
param.name == name ||
param.name.startsWith(name) && param.name(name.length) == '$'
val ps = constrParams filter matchesName
if (ps.isEmpty) assert(false, "" + name + " not in " + constrParams)
ps.head
def matchesName(param: Symbol) = param.name == name || param.name.startsWith(name + "$")

(constrParams filter matchesName) match {
case Nil => assert(false, name + " not in " + constrParams) ; null
case p :: _ => p
}
}

var thisRefSeen: Boolean = false
Expand All @@ -79,7 +76,7 @@ abstract class Constructors extends Transform with ast.TreeDSL {
// A transformer for expressions that go into the constructor
val intoConstructorTransformer = new Transformer {
def isParamRef(sym: Symbol) =
(sym hasFlag PARAMACCESSOR) &&
sym.isParamAccessor &&
sym.owner == clazz &&
!(sym.isGetter && sym.accessed.isVariable) &&
!sym.isSetter
Expand Down Expand Up @@ -133,33 +130,28 @@ abstract class Constructors extends Transform with ast.TreeDSL {

// Create an assignment to class field `to' with rhs `from'
def mkAssign(to: Symbol, from: Tree): Tree =
localTyper.typed {
//util.trace("compiling "+unit+" ") {
atPos(to.pos) {
Assign(Select(This(clazz), to), from)
}
//}
}
localTyper.typedPos(to.pos) { Assign(Select(This(clazz), to), from) }

// Create code to copy parameter to parameter accessor field.
// If parameter is $outer, check that it is not null.
// If parameter is $outer, check that it is not null so that we NPE
// here instead of at some unknown future $outer access.
def copyParam(to: Symbol, from: Symbol): Tree = {
import CODE._
var result = mkAssign(to, Ident(from))
if (from.name == nme.OUTER)
result =
atPos(to.pos) {
localTyper.typed {
IF (from OBJ_EQ NULL) THEN THROW(NullPointerExceptionClass) ELSE result
}
}
val result = mkAssign(to, Ident(from))

result
if (from.name != nme.OUTER) result
else localTyper.typedPos(to.pos) {
IF (from OBJ_EQ NULL) THEN THROW(NullPointerExceptionClass) ELSE result
}
}

// The list of definitions that go into class
val defBuf = new ListBuffer[Tree]

// The auxiliary constructors, separate from the defBuf since they should
// follow the primary constructor
val auxConstructorBuf = new ListBuffer[Tree]

// The list of statements that go into constructor after superclass constructor call
val constrStatBuf = new ListBuffer[Tree]

Expand All @@ -183,7 +175,7 @@ abstract class Constructors extends Transform with ast.TreeDSL {
}
}

// Triage all template definitions to go into defBuf, constrStatBuf, or constrPrefixBuf.
// Triage all template definitions to go into defBuf/auxConstructorBuf, constrStatBuf, or constrPrefixBuf.
for (stat <- stats) stat match {
case DefDef(mods, name, tparams, vparamss, tpt, rhs) =>
// methods with constant result type get literals as their body
Expand All @@ -194,7 +186,9 @@ abstract class Constructors extends Transform with ast.TreeDSL {
stat, mods, name, tparams, vparamss, tpt,
Literal(c) setPos rhs.pos setType tp)
case _ =>
if (!stat.symbol.isPrimaryConstructor) defBuf += stat
if (stat.symbol.isPrimaryConstructor) ()
else if (stat.symbol.isConstructor) auxConstructorBuf += stat
else defBuf += stat
}
case ValDef(mods, name, tpt, rhs) =>
// val defs with constant right-hand sides are eliminated.
Expand Down Expand Up @@ -238,8 +232,7 @@ abstract class Constructors extends Transform with ast.TreeDSL {

// Is symbol known to be accessed outside of the primary constructor,
// or is it a symbol whose definition cannot be omitted anyway?
def mustbeKept(sym: Symbol) =
!maybeOmittable(sym) || (accessedSyms contains sym)
def mustbeKept(sym: Symbol) = !maybeOmittable(sym) || accessedSyms(sym)

// A traverser to set accessedSyms and outerAccessors
val accessTraverser = new Traverser {
Expand All @@ -263,7 +256,8 @@ abstract class Constructors extends Transform with ast.TreeDSL {

// first traverse all definitions except outeraccesors
// (outeraccessors are avoided in accessTraverser)
for (stat <- defBuf.iterator) accessTraverser.traverse(stat)
for (stat <- defBuf.iterator ++ auxConstructorBuf.iterator)
accessTraverser.traverse(stat)

// then traverse all bodies of outeraccessors which are accessed themselves
// note: this relies on the fact that an outer accessor never calls another
Expand Down Expand Up @@ -418,6 +412,9 @@ abstract class Constructors extends Transform with ast.TreeDSL {
paramInits ::: constrPrefixBuf.toList ::: guardSpecializedInitializer(constrStatBuf.toList),
constrBody.expr));

// Followed by any auxiliary constructors
defBuf ++= auxConstructorBuf

// Unlink all fields that can be dropped from class scope
for (sym <- clazz.info.decls.toList)
if (!mustbeKept(sym)) clazz.info.decls unlink sym
Expand Down

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