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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
package scalac.transformer;
import scalac.Global;
import scalac.util.Name;
import scalac.util.Names;
import scalac.ast.Tree;
import Tree.*;
import scalac.ast.Transformer;
import scalac.symtab.Type;
import scalac.symtab.Symbol;
import scalac.symtab.TermSymbol;
import scalac.symtab.Scope;
import scalac.symtab.Kinds;
import scalac.symtab.Modifiers;
import java.util.HashMap;
import java.util.HashSet;
import java.util.ArrayList;
import scalac.util.Debug;
/**
* 1. For each class add a single method (DefDef) designated as
* constructor whose parameters are the class parameters and the
* owner is the constructed class. The constructor contains:
*
* - call to the constructor of the supertype with the appropriate arguments
* - initialize the fields corresponding to the class ValDefs
* - the bodies of the class level expressions;
* they are also removed from the ClassDef body
*
* 2. Additional constructors are assigned new symbols owned by the class
*
* 3. The right hand sides of the ValDefs are left empty
*
* 4. Substitute the appropriate constructor symbol into the
* 'new' expressions and constructor applications
*
* @author Nikolay Mihaylov
* @version 1.2
*/
public class AddConstructors extends Transformer {
// True iff we generate code for INT backend.
protected final boolean forINT;
// True iff we generate code for JVM backend.
protected final boolean forJVM;
protected final HashMap/*<Symbol, Symbol>*/ constructors;
public AddConstructors(Global global, HashMap constructors) {
super(global);
this.constructors = constructors;
this.forINT = global.target == global.TARGET_INT;
this.forJVM = (global.target == global.TARGET_JVM
|| global.target == global.TARGET_JVM_BCEL);
}
/** return new constructor symbol if it isn't already defined
*/
Symbol getConstructor(Symbol classConstr) {
assert classConstr.isConstructor() :
"Class constructor expected: " + Debug.show(classConstr);
Symbol owner = classConstr.constructorClass();
Symbol[] tparamSyms = classConstr.typeParams();
Symbol[] paramSyms = classConstr.valueParams();
Symbol constr = (Symbol) constructors.get(classConstr);
if (constr == null) {
assert !owner.isInterface() : Debug.show(owner) + " is interface";
int flags =
classConstr.flags & (Modifiers.PRIVATE | Modifiers.PROTECTED);
constr =
new TermSymbol(classConstr.pos, classConstr.name, owner, flags);
Type constrType = Type.MethodType
(paramSyms, forJVM ?
global.definitions.UNIT_TYPE : owner.type());
if (tparamSyms.length != 0)
constrType = Type.PolyType(tparamSyms, constrType);
constr.setInfo(constrType);
constructors.put(classConstr, constr);
constructors.put(constr, constr);
owner.members().enterOrOverload(constr);
}
return constr;
}
/** process the tree
*/
public Tree transform(Tree tree) {
final Symbol treeSym = tree.symbol();
switch (tree) {
case ClassDef(_, _, _, _, _, Template impl):
if (treeSym.isInterface())
return super.transform(tree);
// expressions that go before the call to the super constructor
final ArrayList constrBody = new ArrayList();
// expressions that go after the call to the super constructor
final ArrayList constrBody2 = new ArrayList();
// the body of the class after the transformation
final ArrayList classBody = new ArrayList();
// the Symbol of the new primary constructor
final Symbol constrSym =
getConstructor(treeSym.primaryConstructor());
assert constrSym.owner() == treeSym :
"Wrong owner of the constructor: \n\tfound: " +
Debug.show(constrSym.owner()) + "\n\texpected: " +
Debug.show(treeSym);
for (int i = 0; i < impl.body.length; i++) {
Tree t = impl.body[i];
if (t.definesSymbol()) {
Symbol sym = t.symbol();
switch (t) {
// for ValDefs move the initialization code to the constructor
case ValDef(_, _, _, Tree rhs):
if (rhs != Tree.Empty) {
Tree lhs =
gen.Select(gen.This(t.pos, treeSym), sym);
Tree assign =
gen.Assign(t.pos, lhs, transform(rhs));
t = gen.ValDef(sym, Tree.Empty);
if (rhs.hasSymbol() && rhs.symbol().isParameter()) {
constrBody.add(assign);
} else {
constrBody2.add(assign);
}
}
break;
// assign new symbols to the alternative constructors
case DefDef(_, _, _, _, _, Tree rhs):
if (sym.isConstructor()) {
// add result expression consistent with the
// result type of the constructor
Tree result = forJVM
? gen.mkUnitLit(t.pos)
: gen.This(t.pos, treeSym);
rhs = gen.mkBlock(new Tree[] { rhs, result });
t = gen.DefDef(getConstructor(sym), rhs);
}
break;
}
// do not transform(t). It will be done at the end
classBody.add(t);
} else {
// move class-level expressions into the constructor
constrBody2.add(transform(impl.body[i]));
}
}
// inline the call to the super constructor
if ( !forINT || !treeSym.parents()[0].symbol().isJava()) {
switch (impl.parents[0]) {
case Apply(TypeApply(Tree fun, Tree[] targs), Tree[] args):
int pos = impl.parents[0].pos;
Tree superConstr = gen.Select
(gen.Super(pos, treeSym),
getConstructor(fun.symbol()));
constrBody.add(gen.mkApplyTV(superConstr, transform(targs), transform(args)));
break;
case Apply(Tree fun, Tree[] args):
int pos = impl.parents[0].pos;
Tree superConstr = gen.Select
(gen.Super(pos, treeSym),
getConstructor(fun.symbol()));
constrBody.add(gen.mkApply_V(superConstr, transform(args)));
break;
default:
throw Debug.abort("illegal case", impl.parents[0]);
}
}
// inline initialization of module values
if (forINT && treeSym.isModuleClass()) {
Symbol module = treeSym.module();
if (module.isGlobalModule()) {
constrBody.add(
gen.Assign(
gen.mkRef(tree.pos, module),
gen.This(tree.pos, treeSym)));
} else {
Symbol owner = module.owner();
Name module_eqname = module.name.append(Names._EQ);
Symbol module_eq = owner.lookup(module_eqname);
assert module != Symbol.NONE :Debug.show(treeSym.module());
if (owner.isModuleClass() && owner.module().isStable()) {
constrBody.add(
gen.mkApply_V(
gen.mkRef(tree.pos, module_eq),
new Tree[] {gen.This(tree.pos, treeSym)}));
} else {
// !!! module_eq must be accessed via some outer field
}
}
}
// add valdefs and class-level expression to the constructorr body
constrBody.addAll(constrBody2);
// add result expression consistent with the
// result type of the constructor
if (! forJVM)
constrBody.add(gen.This(tree.pos, treeSym));
else
constrBody.add(gen.mkUnitLit(tree.pos));
Tree constrTree = constrBody.size() > 1 ?
gen.Block((Tree[])constrBody.
toArray(new Tree[constrBody.size()])):
(Tree) constrBody.get(0);
classBody.add(gen.DefDef(constrSym, constrTree));
Tree[] newBody = (Tree[]) classBody.toArray(Tree.EMPTY_ARRAY);
// transform the bodies of all members in order to substitute
// the constructor references with the new ones
for (int i = 0; i < newBody.length - 1; i ++)
newBody[i] = transform(newBody[i]);
return gen.ClassDef(treeSym, newBody);
// Substitute the constructor into the 'new' expressions
case New(Template(Tree[] baseClasses, _)):
Tree base = baseClasses[0];
switch (base) {
case Apply(TypeApply(Tree fun, Tree[] targs), Tree[] args):
return gen.New(
tree.pos,
gen.mkApplyTV(
base.pos,
gen.Ident(fun.pos, getConstructor(fun.symbol())),
transform(targs),
transform(args)));
case Apply(Tree fun, Tree[] args):
return gen.New(
tree.pos,
gen.mkApply_V(
base.pos,
gen.Ident(fun.pos, getConstructor(fun.symbol())),
transform(args)));
default:
assert false;
}
break;
// Substitute the constructor aplication;
// this only occurs within constructors that terminate
// by a call to another constructor of the same class
case Apply(TypeApply(Tree fun, Tree[] targs), Tree[] args):
Symbol constr = (Symbol)constructors.get(fun.symbol());
if (constr != null)
return gen.mkApplyTV(
tree.pos,
gen.Select(fun.pos, gen.This(fun.pos, constr.owner()), constr),
transform(targs),
transform(args));
break;
case Apply(Tree fun, Tree[] args):
Symbol constr = (Symbol)constructors.get(fun.symbol());
if (constr != null)
return gen.mkApply_V(
tree.pos,
gen.Select(fun.pos, gen.This(fun.pos, constr.owner()), constr),
transform(args));
break;
} // switch(tree)
return super.transform(tree);
} // transform()
} // class AddConstructors
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