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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. 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. The right hand sides of the ValDefs are left empty
*
* 3. Substitute the appropriate constructor symbol into the
* 'new' expressions
*
* @author Nikolay Mihaylov
* @version 1.2
*/
public class AddConstructors extends Transformer {
public final static Name CTOR_N = Names.CONSTRUCTOR;
// True iff we generate code for INT backend.
protected final boolean forINT;
// True iff we generate code for JVM backend.
protected final boolean forJVM;
// True iff we generate code for MSIL backend.
protected final boolean forMSIL;
final HashMap 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);
this.forMSIL = global.target == global.TARGET_MSIL;
}
/** return new constructor symbol if it isn't already defined
*/
Symbol getConstructor(Symbol classConstr) {
return getConstructor(classConstr,
(((Type.MethodType)classConstr.info()).vparams),
classConstr.primaryConstructorClass());
}
Symbol getConstructor(Symbol classConstr, Symbol[] paramSyms, Symbol owner) {
assert classConstr.isConstructor() :
"Class constructor expected: " + Debug.show(classConstr);
Symbol constr = (Symbol) constructors.get(classConstr);
if (constr == null) {
assert !owner.isInterface() : Debug.show(owner) + " is interface";
int flags = forJVM
? classConstr.flags & (Modifiers.PRIVATE | Modifiers.PROTECTED)
: classConstr.flags;
constr =
new TermSymbol(classConstr.pos, CTOR_N, owner, flags);
Type constrType = Type.MethodType
(paramSyms, forJVM ?
global.definitions.UNIT_TYPE : owner.type()).erasure();
constr.setInfo(constrType.erasure());
constructors.put(classConstr, constr);
constructors.put(constr, constr);
}
return constr;
}
/** process the tree
*/
public Tree transform(Tree tree) {
Symbol treeSym = tree.symbol();
switch (tree) {
case ClassDef(_, _, _, ValDef[][] vparams, _, //:
Template(Tree[] baseClasses, Tree[] body)):
assert treeSym.name.isTypeName();
if (treeSym.isInterface())
return super.transform(tree);
Symbol[] paramSyms = new Symbol[vparams[0].length];
for (int i = 0; i < paramSyms.length; i++)
paramSyms[i] = vparams[0][i].symbol();
ArrayList constrBody = new ArrayList();
ArrayList constrBody2 = new ArrayList();
ArrayList classBody = new ArrayList();
Symbol constrSym =
getConstructor(treeSym.constructor(), paramSyms, treeSym);
Scope classScope = new Scope();
classScope.enter(constrSym);
assert constrSym.owner() == treeSym :
"Wrong owner of the constructor: \n\tfound: " +
Debug.show(constrSym.owner()) + "\n\texpected: " +
Debug.show(treeSym);
// for every ValDef move the initialization code into the constructor
for (int i = 0; i < body.length; i++) {
Tree t = body[i];
if (t.definesSymbol()) {
Symbol sym = t.symbol();
switch (t) {
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;
}
classBody.add(transform(t));
classScope.enterOrOverload(sym);
} else {
// move class-level expressions into the constructor
constrBody2.add(transform(body[i]));
}
}
// inline the call to the super constructor
if ( !forINT || !treeSym.parents()[0].symbol().isJava()) {
switch (baseClasses[0]) {
case Apply(Tree fun, Tree[] args):
int pos = baseClasses[0].pos;
Tree superConstr = gen.Select
(gen.Super(pos, treeSym),
getConstructor(fun.symbol()));
constrBody.add(gen.Apply(superConstr, transform(args)));
break;
default:
new scalac.ast.printer.TextTreePrinter().
print(baseClasses[0]).println().end();
assert false;
}
}
// 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.Apply(
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));
Tree constrTree = constrBody.size() > 1 ?
gen.Block((Tree[])constrBody.
toArray(new Tree[constrBody.size()])):
(Tree) constrBody.get(0);
classBody.add(gen.DefDef(tree.pos, constrSym, constrTree));
// strip off the class constructor from parameters
switch (treeSym.constructor().info()) {
case MethodType(_, Type result):
treeSym.constructor().
updateInfo(Type.MethodType(Symbol.EMPTY_ARRAY, result));
break;
default : assert false;
}
Type classType =
Type.compoundType(treeSym.parents(), classScope, treeSym);
Symbol classSym = treeSym.updateInfo(classType);
Tree[] newBody = (Tree[]) classBody.toArray(Tree.EMPTY_ARRAY);
return gen.ClassDef(classSym, baseClasses, newBody);
// Substitute the constructor into the 'new' expressions
case New(Template(Tree[] baseClasses, _)):
Tree base = baseClasses[0];
switch (base) {
case Apply(Tree fun, Tree[] args):
return gen.New(copy.Apply
(base,
gen.Ident(base.pos, getConstructor(fun.symbol())),
transform(args)));
default:
assert false;
}
break;
} // switch(tree)
return super.transform(tree);
} // transform()
} // class AddConstructors
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