/* * Copyright (c) 1999, 2008, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.sun.tools.javac.comp; import java.util.*; import javax.lang.model.element.ElementKind; import com.sun.tools.javac.code.*; import com.sun.tools.javac.code.Symbol.*; import com.sun.tools.javac.tree.*; import com.sun.tools.javac.tree.JCTree.*; import com.sun.tools.javac.util.*; import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition; import com.sun.tools.javac.util.List; import static com.sun.tools.javac.code.Flags.*; import static com.sun.tools.javac.code.Kinds.*; import static com.sun.tools.javac.code.TypeTags.*; /** This pass translates Generic Java to conventional Java. * *

This is NOT part of any supported API. * If you write code that depends on this, you do so at your own risk. * This code and its internal interfaces are subject to change or * deletion without notice. */ public class TransTypes extends TreeTranslator { /** The context key for the TransTypes phase. */ protected static final Context.Key transTypesKey = new Context.Key(); /** Get the instance for this context. */ public static TransTypes instance(Context context) { TransTypes instance = context.get(transTypesKey); if (instance == null) instance = new TransTypes(context); return instance; } private Names names; private Log log; private Symtab syms; private TreeMaker make; private Enter enter; private boolean allowEnums; private Types types; private final Resolve resolve; private final TypeAnnotations typeAnnotations; /** * Flag to indicate whether or not to generate bridge methods. * For pre-Tiger source there is no need for bridge methods, so it * can be skipped to get better performance for -source 1.4 etc. */ private final boolean addBridges; protected TransTypes(Context context) { context.put(transTypesKey, this); names = Names.instance(context); log = Log.instance(context); syms = Symtab.instance(context); enter = Enter.instance(context); overridden = new HashMap(); Source source = Source.instance(context); allowEnums = source.allowEnums(); addBridges = source.addBridges(); types = Types.instance(context); make = TreeMaker.instance(context); resolve = Resolve.instance(context); typeAnnotations = TypeAnnotations.instance(context); } /** A hashtable mapping bridge methods to the methods they override after * type erasure. */ Map overridden; /** Construct an attributed tree for a cast of expression to target type, * unless it already has precisely that type. * @param tree The expression tree. * @param target The target type. */ JCExpression cast(JCExpression tree, Type target) { int oldpos = make.pos; make.at(tree.pos); if (!types.isSameType(tree.type, target)) { if (!resolve.isAccessible(env, target.tsym)) resolve.logAccessError(env, tree, target); tree = make.TypeCast(make.Type(target), tree).setType(target); } make.pos = oldpos; return tree; } /** Construct an attributed tree to coerce an expression to some erased * target type, unless the expression is already assignable to that type. * If target type is a constant type, use its base type instead. * @param tree The expression tree. * @param target The target type. */ JCExpression coerce(JCExpression tree, Type target) { Type btarget = target.baseType(); if (tree.type.isPrimitive() == target.isPrimitive()) { return types.isAssignable(tree.type, btarget, Warner.noWarnings) ? tree : cast(tree, btarget); } return tree; } /** Given an erased reference type, assume this type as the tree's type. * Then, coerce to some given target type unless target type is null. * This operation is used in situations like the following: * * class Cell { A value; } * ... * Cell cell; * Integer x = cell.value; * * Since the erasure of Cell.value is Object, but the type * of cell.value in the assignment is Integer, we need to * adjust the original type of cell.value to Object, and insert * a cast to Integer. That is, the last assignment becomes: * * Integer x = (Integer)cell.value; * * @param tree The expression tree whose type might need adjustment. * @param erasedType The expression's type after erasure. * @param target The target type, which is usually the erasure of the * expression's original type. */ JCExpression retype(JCExpression tree, Type erasedType, Type target) { // System.err.println("retype " + tree + " to " + erasedType);//DEBUG if (erasedType.tag > lastBaseTag) { if (target != null && target.isPrimitive()) target = erasure(tree.type); tree.type = erasedType; if (target != null) return coerce(tree, target); } return tree; } /** Translate method argument list, casting each argument * to its corresponding type in a list of target types. * @param _args The method argument list. * @param parameters The list of target types. * @param varargsElement The erasure of the varargs element type, * or null if translating a non-varargs invocation */ List translateArgs(List _args, List parameters, Type varargsElement) { if (parameters.isEmpty()) return _args; List args = _args; while (parameters.tail.nonEmpty()) { args.head = translate(args.head, parameters.head); args = args.tail; parameters = parameters.tail; } Type parameter = parameters.head; assert varargsElement != null || args.length() == 1; if (varargsElement != null) { while (args.nonEmpty()) { args.head = translate(args.head, varargsElement); args = args.tail; } } else { args.head = translate(args.head, parameter); } return _args; } /** Add a bridge definition and enter corresponding method symbol in * local scope of origin. * * @param pos The source code position to be used for the definition. * @param meth The method for which a bridge needs to be added * @param impl That method's implementation (possibly the method itself) * @param origin The class to which the bridge will be added * @param hypothetical * True if the bridge method is not strictly necessary in the * binary, but is represented in the symbol table to detect * erasure clashes. * @param bridges The list buffer to which the bridge will be added */ void addBridge(DiagnosticPosition pos, MethodSymbol meth, MethodSymbol impl, ClassSymbol origin, boolean hypothetical, ListBuffer bridges) { make.at(pos); Type origType = types.memberType(origin.type, meth); Type origErasure = erasure(origType); // Create a bridge method symbol and a bridge definition without a body. Type bridgeType = meth.erasure(types); long flags = impl.flags() & AccessFlags | SYNTHETIC | BRIDGE; if (hypothetical) flags |= HYPOTHETICAL; MethodSymbol bridge = new MethodSymbol(flags, meth.name, bridgeType, origin); if (!hypothetical) { JCMethodDecl md = make.MethodDef(bridge, null); // The bridge calls this.impl(..), if we have an implementation // in the current class, super.impl(...) otherwise. JCExpression receiver = (impl.owner == origin) ? make.This(origin.erasure(types)) : make.Super(types.supertype(origin.type).tsym.erasure(types), origin); // The type returned from the original method. Type calltype = erasure(impl.type.getReturnType()); // Construct a call of this.impl(params), or super.impl(params), // casting params and possibly results as needed. JCExpression call = make.Apply( null, make.Select(receiver, impl).setType(calltype), translateArgs(make.Idents(md.params), origErasure.getParameterTypes(), null)) .setType(calltype); JCStatement stat = (origErasure.getReturnType().tag == VOID) ? make.Exec(call) : make.Return(coerce(call, bridgeType.getReturnType())); md.body = make.Block(0, List.of(stat)); // Add bridge to `bridges' buffer bridges.append(md); } // Add bridge to scope of enclosing class and `overridden' table. origin.members().enter(bridge); overridden.put(bridge, meth); } /** Add bridge if given symbol is a non-private, non-static member * of the given class, which is either defined in the class or non-final * inherited, and one of the two following conditions holds: * 1. The method's type changes in the given class, as compared to the * class where the symbol was defined, (in this case * we have extended a parameterized class with non-trivial parameters). * 2. The method has an implementation with a different erased return type. * (in this case we have used co-variant returns). * If a bridge already exists in some other class, no new bridge is added. * Instead, it is checked that the bridge symbol overrides the method symbol. * (Spec ???). * todo: what about bridges for privates??? * * @param pos The source code position to be used for the definition. * @param sym The symbol for which a bridge might have to be added. * @param origin The class in which the bridge would go. * @param bridges The list buffer to which the bridge would be added. */ void addBridgeIfNeeded(DiagnosticPosition pos, Symbol sym, ClassSymbol origin, ListBuffer bridges) { if (sym.kind == MTH && sym.name != names.init && (sym.flags() & (PRIVATE | SYNTHETIC | STATIC)) == 0 && sym.isMemberOf(origin, types)) { MethodSymbol meth = (MethodSymbol)sym; MethodSymbol bridge = meth.binaryImplementation(origin, types); MethodSymbol impl = meth.implementation(origin, types, true); if (bridge == null || bridge == meth || (impl != null && !bridge.owner.isSubClass(impl.owner, types))) { // No bridge was added yet. if (impl != null && isBridgeNeeded(meth, impl, origin.type)) { addBridge(pos, meth, impl, origin, bridge==impl, bridges); } else if (impl == meth && impl.owner != origin && (impl.flags() & FINAL) == 0 && (meth.flags() & (ABSTRACT|PUBLIC)) == PUBLIC && (origin.flags() & PUBLIC) > (impl.owner.flags() & PUBLIC)) { // this is to work around a horrible but permanent // reflection design error. addBridge(pos, meth, impl, origin, false, bridges); } } else if ((bridge.flags() & SYNTHETIC) != 0) { MethodSymbol other = overridden.get(bridge); if (other != null && other != meth) { if (impl == null || !impl.overrides(other, origin, types, true)) { // Bridge for other symbol pair was added log.error(pos, "name.clash.same.erasure.no.override", other, other.location(origin.type, types), meth, meth.location(origin.type, types)); } } } else if (!bridge.overrides(meth, origin, types, true)) { // Accidental binary override without source override. if (bridge.owner == origin || types.asSuper(bridge.owner.type, meth.owner) == null) // Don't diagnose the problem if it would already // have been reported in the superclass log.error(pos, "name.clash.same.erasure.no.override", bridge, bridge.location(origin.type, types), meth, meth.location(origin.type, types)); } } } // where /** * @param method The symbol for which a bridge might have to be added * @param impl The implementation of method * @param dest The type in which the bridge would go */ private boolean isBridgeNeeded(MethodSymbol method, MethodSymbol impl, Type dest) { if (impl != method) { // If either method or impl have different erasures as // members of dest, a bridge is needed. Type method_erasure = method.erasure(types); if (!isSameMemberWhenErased(dest, method, method_erasure)) return true; Type impl_erasure = impl.erasure(types); if (!isSameMemberWhenErased(dest, impl, impl_erasure)) return true; // If the erasure of the return type is different, a // bridge is needed. return !types.isSameType(impl_erasure.getReturnType(), method_erasure.getReturnType()); } else { // method and impl are the same... if ((method.flags() & ABSTRACT) != 0) { // ...and abstract so a bridge is not needed. // Concrete subclasses will bridge as needed. return false; } // The erasure of the return type is always the same // for the same symbol. Reducing the three tests in // the other branch to just one: return !isSameMemberWhenErased(dest, method, method.erasure(types)); } } /** * Lookup the method as a member of the type. Compare the * erasures. * @param type the class where to look for the method * @param method the method to look for in class * @param erasure the erasure of method */ private boolean isSameMemberWhenErased(Type type, MethodSymbol method, Type erasure) { return types.isSameType(erasure(types.memberType(type, method)), erasure); } void addBridges(DiagnosticPosition pos, TypeSymbol i, ClassSymbol origin, ListBuffer bridges) { for (Scope.Entry e = i.members().elems; e != null; e = e.sibling) addBridgeIfNeeded(pos, e.sym, origin, bridges); for (List l = types.interfaces(i.type); l.nonEmpty(); l = l.tail) addBridges(pos, l.head.tsym, origin, bridges); } /** Add all necessary bridges to some class appending them to list buffer. * @param pos The source code position to be used for the bridges. * @param origin The class in which the bridges go. * @param bridges The list buffer to which the bridges are added. */ void addBridges(DiagnosticPosition pos, ClassSymbol origin, ListBuffer bridges) { Type st = types.supertype(origin.type); while (st.tag == CLASS) { // if (isSpecialization(st)) addBridges(pos, st.tsym, origin, bridges); st = types.supertype(st); } for (List l = types.interfaces(origin.type); l.nonEmpty(); l = l.tail) // if (isSpecialization(l.head)) addBridges(pos, l.head.tsym, origin, bridges); } /* ************************************************************************ * Visitor methods *************************************************************************/ /** Visitor argument: proto-type. */ private Type pt; /** Visitor method: perform a type translation on tree. */ public T translate(T tree, Type pt) { Type prevPt = this.pt; try { this.pt = pt; return translate(tree); } finally { this.pt = prevPt; } } /** Visitor method: perform a type translation on list of trees. */ public List translate(List trees, Type pt) { Type prevPt = this.pt; List res; try { this.pt = pt; res = translate(trees); } finally { this.pt = prevPt; } return res; } public void visitClassDef(JCClassDecl tree) { typeAnnotations.taFillAndLift(tree, true); translateClass(tree.sym); result = tree; } JCMethodDecl currentMethod = null; public void visitMethodDef(JCMethodDecl tree) { tree.sym.typeAnnotations = tree.sym.typeAnnotations; JCMethodDecl previousMethod = currentMethod; try { currentMethod = tree; tree.restype = translate(tree.restype, null); tree.typarams = List.nil(); tree.params = translateVarDefs(tree.params); tree.thrown = translate(tree.thrown, null); tree.body = translate(tree.body, tree.sym.erasure(types).getReturnType()); tree.type = erasure(tree.type); result = tree; } finally { currentMethod = previousMethod; } // Check that we do not introduce a name clash by erasing types. for (Scope.Entry e = tree.sym.owner.members().lookup(tree.name); e.sym != null; e = e.next()) { if (e.sym != tree.sym && types.isSameType(erasure(e.sym.type), tree.type)) { log.error(tree.pos(), "name.clash.same.erasure", tree.sym, e.sym); return; } } } public void visitVarDef(JCVariableDecl tree) { tree.vartype = translate(tree.vartype, null); tree.init = translate(tree.init, tree.sym.erasure(types)); tree.type = erasure(tree.type); result = tree; } public void visitDoLoop(JCDoWhileLoop tree) { tree.body = translate(tree.body); tree.cond = translate(tree.cond, syms.booleanType); result = tree; } public void visitWhileLoop(JCWhileLoop tree) { tree.cond = translate(tree.cond, syms.booleanType); tree.body = translate(tree.body); result = tree; } public void visitForLoop(JCForLoop tree) { tree.init = translate(tree.init, null); if (tree.cond != null) tree.cond = translate(tree.cond, syms.booleanType); tree.step = translate(tree.step, null); tree.body = translate(tree.body); result = tree; } public void visitForeachLoop(JCEnhancedForLoop tree) { tree.var = translate(tree.var, null); Type iterableType = tree.expr.type; tree.expr = translate(tree.expr, erasure(tree.expr.type)); if (types.elemtype(tree.expr.type) == null) tree.expr.type = iterableType; // preserve type for Lower tree.body = translate(tree.body); result = tree; } public void visitSwitch(JCSwitch tree) { Type selsuper = types.supertype(tree.selector.type); boolean enumSwitch = selsuper != null && selsuper.tsym == syms.enumSym; Type target = enumSwitch ? erasure(tree.selector.type) : syms.intType; tree.selector = translate(tree.selector, target); tree.cases = translateCases(tree.cases); result = tree; } public void visitCase(JCCase tree) { tree.pat = translate(tree.pat, null); tree.stats = translate(tree.stats); result = tree; } public void visitSynchronized(JCSynchronized tree) { tree.lock = translate(tree.lock, erasure(tree.lock.type)); tree.body = translate(tree.body); result = tree; } public void visitTry(JCTry tree) { tree.resources = translate(tree.resources, syms.autoCloseableType); tree.body = translate(tree.body); tree.catchers = translateCatchers(tree.catchers); tree.finalizer = translate(tree.finalizer); result = tree; } public void visitConditional(JCConditional tree) { tree.cond = translate(tree.cond, syms.booleanType); tree.truepart = translate(tree.truepart, erasure(tree.type)); tree.falsepart = translate(tree.falsepart, erasure(tree.type)); tree.type = erasure(tree.type); result = retype(tree, tree.type, pt); } public void visitIf(JCIf tree) { tree.cond = translate(tree.cond, syms.booleanType); tree.thenpart = translate(tree.thenpart); tree.elsepart = translate(tree.elsepart); result = tree; } public void visitExec(JCExpressionStatement tree) { tree.expr = translate(tree.expr, null); result = tree; } public void visitReturn(JCReturn tree) { tree.expr = translate(tree.expr, currentMethod.sym.erasure(types).getReturnType()); result = tree; } public void visitThrow(JCThrow tree) { tree.expr = translate(tree.expr, erasure(tree.expr.type)); result = tree; } public void visitAssert(JCAssert tree) { tree.cond = translate(tree.cond, syms.booleanType); if (tree.detail != null) tree.detail = translate(tree.detail, erasure(tree.detail.type)); result = tree; } public void visitApply(JCMethodInvocation tree) { tree.meth = translate(tree.meth, null); Symbol meth = TreeInfo.symbol(tree.meth); Type mt = meth.erasure(types); List argtypes = mt.getParameterTypes(); if (allowEnums && meth.name==names.init && meth.owner == syms.enumSym) argtypes = argtypes.tail.tail; if (tree.varargsElement != null) tree.varargsElement = types.erasure(tree.varargsElement); else assert tree.args.length() == argtypes.length(); tree.args = translateArgs(tree.args, argtypes, tree.varargsElement); // Insert casts of method invocation results as needed. result = retype(tree, mt.getReturnType(), pt); } public void visitNewClass(JCNewClass tree) { if (tree.encl != null) tree.encl = translate(tree.encl, erasure(tree.encl.type)); tree.clazz = translate(tree.clazz, null); if (tree.varargsElement != null) tree.varargsElement = types.erasure(tree.varargsElement); tree.args = translateArgs( tree.args, tree.constructor.erasure(types).getParameterTypes(), tree.varargsElement); tree.def = translate(tree.def, null); tree.type = erasure(tree.type); result = tree; } public void visitNewArray(JCNewArray tree) { tree.elemtype = translate(tree.elemtype, null); translate(tree.dims, syms.intType); if (tree.type != null) { tree.elems = translate(tree.elems, erasure(types.elemtype(tree.type))); tree.type = erasure(tree.type); } else { tree.elems = translate(tree.elems, null); } result = tree; } public void visitParens(JCParens tree) { tree.expr = translate(tree.expr, pt); tree.type = erasure(tree.type); result = tree; } public void visitAssign(JCAssign tree) { tree.lhs = translate(tree.lhs, null); tree.rhs = translate(tree.rhs, erasure(tree.lhs.type)); tree.type = erasure(tree.type); result = tree; } public void visitAssignop(JCAssignOp tree) { tree.lhs = translate(tree.lhs, null); tree.rhs = translate(tree.rhs, tree.operator.type.getParameterTypes().tail.head); tree.type = erasure(tree.type); result = tree; } public void visitUnary(JCUnary tree) { tree.arg = translate(tree.arg, tree.operator.type.getParameterTypes().head); result = tree; } public void visitBinary(JCBinary tree) { tree.lhs = translate(tree.lhs, tree.operator.type.getParameterTypes().head); tree.rhs = translate(tree.rhs, tree.operator.type.getParameterTypes().tail.head); result = tree; } public void visitTypeCast(JCTypeCast tree) { tree.clazz = translate(tree.clazz, null); tree.type = erasure(tree.type); tree.expr = translate(tree.expr, tree.type); result = tree; } public void visitTypeTest(JCInstanceOf tree) { tree.expr = translate(tree.expr, null); tree.clazz = translate(tree.clazz, null); result = tree; } public void visitIndexed(JCArrayAccess tree) { tree.indexed = translate(tree.indexed, erasure(tree.indexed.type)); tree.index = translate(tree.index, syms.intType); // Insert casts of indexed expressions as needed. result = retype(tree, types.elemtype(tree.indexed.type), pt); } // There ought to be nothing to rewrite here; // we don't generate code. public void visitAnnotation(JCAnnotation tree) { result = tree; } public void visitIdent(JCIdent tree) { Type et = tree.sym.erasure(types); // Map type variables to their bounds. if (tree.sym.kind == TYP && tree.sym.type.tag == TYPEVAR) { result = make.at(tree.pos).Type(et); } else // Map constants expressions to themselves. if (tree.type.constValue() != null) { result = tree; } // Insert casts of variable uses as needed. else if (tree.sym.kind == VAR) { result = retype(tree, et, pt); } else { tree.type = erasure(tree.type); result = tree; } } public void visitSelect(JCFieldAccess tree) { Type t = tree.selected.type; while (t.tag == TYPEVAR) t = t.getUpperBound(); if (t.isCompound()) { if ((tree.sym.flags() & IPROXY) != 0) { tree.sym = ((MethodSymbol)tree.sym). implemented((TypeSymbol)tree.sym.owner, types); } tree.selected = cast( translate(tree.selected, erasure(tree.selected.type)), erasure(tree.sym.owner.type)); } else tree.selected = translate(tree.selected, erasure(t)); // Map constants expressions to themselves. if (tree.type.constValue() != null) { result = tree; } // Insert casts of variable uses as needed. else if (tree.sym.kind == VAR) { result = retype(tree, tree.sym.erasure(types), pt); } else { tree.type = erasure(tree.type); result = tree; } } public void visitTypeArray(JCArrayTypeTree tree) { tree.elemtype = translate(tree.elemtype, null); tree.type = erasure(tree.type); result = tree; } /** Visitor method for parameterized types. */ public void visitTypeApply(JCTypeApply tree) { JCTree clazz = translate(tree.clazz, null); result = clazz; } /************************************************************************** * utility methods *************************************************************************/ private Type erasure(Type t) { return types.erasure(t); } /************************************************************************** * main method *************************************************************************/ private Env env; void translateClass(ClassSymbol c) { Type st = types.supertype(c.type); // process superclass before derived if (st.tag == CLASS) translateClass((ClassSymbol)st.tsym); Env myEnv = enter.typeEnvs.remove(c); if (myEnv == null) return; Env oldEnv = env; try { env = myEnv; // class has not been translated yet TreeMaker savedMake = make; Type savedPt = pt; make = make.forToplevel(env.toplevel); pt = null; try { JCClassDecl tree = (JCClassDecl) env.tree; tree.typarams = List.nil(); super.visitClassDef(tree); make.at(tree.pos); if (addBridges) { ListBuffer bridges = new ListBuffer(); if ((tree.sym.flags() & INTERFACE) == 0) addBridges(tree.pos(), tree.sym, bridges); tree.defs = bridges.toList().prependList(tree.defs); } tree.type = erasure(tree.type); } finally { make = savedMake; pt = savedPt; } } finally { env = oldEnv; } } /** Translate a toplevel class definition. * @param cdef The definition to be translated. */ public JCTree translateTopLevelClass(JCTree cdef, TreeMaker make) { // note that this method does NOT support recursion. this.make = make; pt = null; return translate(cdef, null); } }