/* * Copyright (c) 1999, 2016, 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 com.sun.tools.javac.code.*; import com.sun.tools.javac.code.Kinds.KindSelector; import com.sun.tools.javac.code.Scope.WriteableScope; import com.sun.tools.javac.jvm.*; import com.sun.tools.javac.main.Option.PkgInfo; import com.sun.tools.javac.tree.*; import com.sun.tools.javac.util.*; import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition; import com.sun.tools.javac.util.List; import com.sun.tools.javac.code.Symbol.*; import com.sun.tools.javac.code.Symbol.OperatorSymbol.AccessCode; import com.sun.tools.javac.tree.JCTree.*; import com.sun.tools.javac.code.Type.*; import com.sun.tools.javac.jvm.Target; import com.sun.tools.javac.tree.EndPosTable; import static com.sun.tools.javac.code.Flags.*; import static com.sun.tools.javac.code.Flags.BLOCK; import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE; import static com.sun.tools.javac.code.TypeTag.*; import static com.sun.tools.javac.code.Kinds.Kind.*; import static com.sun.tools.javac.code.Symbol.OperatorSymbol.AccessCode.DEREF; import static com.sun.tools.javac.jvm.ByteCodes.*; import static com.sun.tools.javac.tree.JCTree.JCOperatorExpression.OperandPos.LEFT; import static com.sun.tools.javac.tree.JCTree.Tag.*; /** This pass translates away some syntactic sugar: inner classes, * class literals, assertions, foreach loops, etc. * *

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 Lower extends TreeTranslator { protected static final Context.Key lowerKey = new Context.Key<>(); public static Lower instance(Context context) { Lower instance = context.get(lowerKey); if (instance == null) instance = new Lower(context); return instance; } private final Names names; private final Log log; private final Symtab syms; private final Resolve rs; private final Operators operators; private final Check chk; private final Attr attr; private TreeMaker make; private DiagnosticPosition make_pos; private final ClassWriter writer; private final ConstFold cfolder; private final Target target; private final Source source; private final TypeEnvs typeEnvs; private final Name dollarAssertionsDisabled; private final Name classDollar; private final Name dollarCloseResource; private final Types types; private final boolean debugLower; private final PkgInfo pkginfoOpt; protected Lower(Context context) { context.put(lowerKey, this); names = Names.instance(context); log = Log.instance(context); syms = Symtab.instance(context); rs = Resolve.instance(context); operators = Operators.instance(context); chk = Check.instance(context); attr = Attr.instance(context); make = TreeMaker.instance(context); writer = ClassWriter.instance(context); cfolder = ConstFold.instance(context); target = Target.instance(context); source = Source.instance(context); typeEnvs = TypeEnvs.instance(context); dollarAssertionsDisabled = names. fromString(target.syntheticNameChar() + "assertionsDisabled"); classDollar = names. fromString("class" + target.syntheticNameChar()); dollarCloseResource = names. fromString(target.syntheticNameChar() + "closeResource"); types = Types.instance(context); Options options = Options.instance(context); debugLower = options.isSet("debuglower"); pkginfoOpt = PkgInfo.get(options); } /** The currently enclosing class. */ ClassSymbol currentClass; /** A queue of all translated classes. */ ListBuffer translated; /** Environment for symbol lookup, set by translateTopLevelClass. */ Env attrEnv; /** A hash table mapping syntax trees to their ending source positions. */ EndPosTable endPosTable; /************************************************************************** * Global mappings *************************************************************************/ /** A hash table mapping local classes to their definitions. */ Map classdefs; /** A hash table mapping local classes to a list of pruned trees. */ public Map> prunedTree = new WeakHashMap<>(); /** A hash table mapping virtual accessed symbols in outer subclasses * to the actually referred symbol in superclasses. */ Map actualSymbols; /** The current method definition. */ JCMethodDecl currentMethodDef; /** The current method symbol. */ MethodSymbol currentMethodSym; /** The currently enclosing outermost class definition. */ JCClassDecl outermostClassDef; /** The currently enclosing outermost member definition. */ JCTree outermostMemberDef; /** A map from local variable symbols to their translation (as per LambdaToMethod). * This is required when a capturing local class is created from a lambda (in which * case the captured symbols should be replaced with the translated lambda symbols). */ Map lambdaTranslationMap = null; /** A navigator class for assembling a mapping from local class symbols * to class definition trees. * There is only one case; all other cases simply traverse down the tree. */ class ClassMap extends TreeScanner { /** All encountered class defs are entered into classdefs table. */ public void visitClassDef(JCClassDecl tree) { classdefs.put(tree.sym, tree); super.visitClassDef(tree); } } ClassMap classMap = new ClassMap(); /** Map a class symbol to its definition. * @param c The class symbol of which we want to determine the definition. */ JCClassDecl classDef(ClassSymbol c) { // First lookup the class in the classdefs table. JCClassDecl def = classdefs.get(c); if (def == null && outermostMemberDef != null) { // If this fails, traverse outermost member definition, entering all // local classes into classdefs, and try again. classMap.scan(outermostMemberDef); def = classdefs.get(c); } if (def == null) { // If this fails, traverse outermost class definition, entering all // local classes into classdefs, and try again. classMap.scan(outermostClassDef); def = classdefs.get(c); } return def; } /** A hash table mapping class symbols to lists of free variables. * accessed by them. Only free variables of the method immediately containing * a class are associated with that class. */ Map> freevarCache; /** A navigator class for collecting the free variables accessed * from a local class. There is only one case; all other cases simply * traverse down the tree. This class doesn't deal with the specific * of Lower - it's an abstract visitor that is meant to be reused in * order to share the local variable capture logic. */ abstract class BasicFreeVarCollector extends TreeScanner { /** Add all free variables of class c to fvs list * unless they are already there. */ abstract void addFreeVars(ClassSymbol c); /** If tree refers to a variable in owner of local class, add it to * free variables list. */ public void visitIdent(JCIdent tree) { visitSymbol(tree.sym); } // where abstract void visitSymbol(Symbol _sym); /** If tree refers to a class instance creation expression * add all free variables of the freshly created class. */ public void visitNewClass(JCNewClass tree) { ClassSymbol c = (ClassSymbol)tree.constructor.owner; addFreeVars(c); super.visitNewClass(tree); } /** If tree refers to a superclass constructor call, * add all free variables of the superclass. */ public void visitApply(JCMethodInvocation tree) { if (TreeInfo.name(tree.meth) == names._super) { addFreeVars((ClassSymbol) TreeInfo.symbol(tree.meth).owner); } super.visitApply(tree); } } /** * Lower-specific subclass of {@code BasicFreeVarCollector}. */ class FreeVarCollector extends BasicFreeVarCollector { /** The owner of the local class. */ Symbol owner; /** The local class. */ ClassSymbol clazz; /** The list of owner's variables accessed from within the local class, * without any duplicates. */ List fvs; FreeVarCollector(ClassSymbol clazz) { this.clazz = clazz; this.owner = clazz.owner; this.fvs = List.nil(); } /** Add free variable to fvs list unless it is already there. */ private void addFreeVar(VarSymbol v) { for (List l = fvs; l.nonEmpty(); l = l.tail) if (l.head == v) return; fvs = fvs.prepend(v); } @Override void addFreeVars(ClassSymbol c) { List fvs = freevarCache.get(c); if (fvs != null) { for (List l = fvs; l.nonEmpty(); l = l.tail) { addFreeVar(l.head); } } } @Override void visitSymbol(Symbol _sym) { Symbol sym = _sym; if (sym.kind == VAR || sym.kind == MTH) { while (sym != null && sym.owner != owner) sym = proxies.findFirst(proxyName(sym.name)); if (sym != null && sym.owner == owner) { VarSymbol v = (VarSymbol)sym; if (v.getConstValue() == null) { addFreeVar(v); } } else { if (outerThisStack.head != null && outerThisStack.head != _sym) visitSymbol(outerThisStack.head); } } } /** If tree refers to a class instance creation expression * add all free variables of the freshly created class. */ public void visitNewClass(JCNewClass tree) { ClassSymbol c = (ClassSymbol)tree.constructor.owner; if (tree.encl == null && c.hasOuterInstance() && outerThisStack.head != null) visitSymbol(outerThisStack.head); super.visitNewClass(tree); } /** If tree refers to a qualified this or super expression * for anything but the current class, add the outer this * stack as a free variable. */ public void visitSelect(JCFieldAccess tree) { if ((tree.name == names._this || tree.name == names._super) && tree.selected.type.tsym != clazz && outerThisStack.head != null) visitSymbol(outerThisStack.head); super.visitSelect(tree); } /** If tree refers to a superclass constructor call, * add all free variables of the superclass. */ public void visitApply(JCMethodInvocation tree) { if (TreeInfo.name(tree.meth) == names._super) { Symbol constructor = TreeInfo.symbol(tree.meth); ClassSymbol c = (ClassSymbol)constructor.owner; if (c.hasOuterInstance() && !tree.meth.hasTag(SELECT) && outerThisStack.head != null) visitSymbol(outerThisStack.head); } super.visitApply(tree); } } ClassSymbol ownerToCopyFreeVarsFrom(ClassSymbol c) { if (!c.isLocal()) { return null; } Symbol currentOwner = c.owner; while (currentOwner.owner.kind.matches(KindSelector.TYP) && currentOwner.isLocal()) { currentOwner = currentOwner.owner; } if (currentOwner.owner.kind.matches(KindSelector.VAL_MTH) && c.isSubClass(currentOwner, types)) { return (ClassSymbol)currentOwner; } return null; } /** Return the variables accessed from within a local class, which * are declared in the local class' owner. * (in reverse order of first access). */ List freevars(ClassSymbol c) { List fvs = freevarCache.get(c); if (fvs != null) { return fvs; } if (c.owner.kind.matches(KindSelector.VAL_MTH)) { FreeVarCollector collector = new FreeVarCollector(c); collector.scan(classDef(c)); fvs = collector.fvs; freevarCache.put(c, fvs); return fvs; } else { ClassSymbol owner = ownerToCopyFreeVarsFrom(c); if (owner != null) { fvs = freevarCache.get(owner); freevarCache.put(c, fvs); return fvs; } else { return List.nil(); } } } Map enumSwitchMap = new LinkedHashMap<>(); EnumMapping mapForEnum(DiagnosticPosition pos, TypeSymbol enumClass) { EnumMapping map = enumSwitchMap.get(enumClass); if (map == null) enumSwitchMap.put(enumClass, map = new EnumMapping(pos, enumClass)); return map; } /** This map gives a translation table to be used for enum * switches. * *

For each enum that appears as the type of a switch * expression, we maintain an EnumMapping to assist in the * translation, as exemplified by the following example: * *

we translate * 

     *          switch(colorExpression) {
     *          case red: stmt1;
     *          case green: stmt2;
     *          }
     *
* into * 
     *          switch(Outer$0.$EnumMap$Color[colorExpression.ordinal()]) {
     *          case 1: stmt1;
     *          case 2: stmt2
     *          }
     *
* with the auxiliary table initialized as follows: * 
     *          class Outer$0 {
     *              synthetic final int[] $EnumMap$Color = new int[Color.values().length];
     *              static {
     *                  try { $EnumMap$Color[red.ordinal()] = 1; } catch (NoSuchFieldError ex) {}
     *                  try { $EnumMap$Color[green.ordinal()] = 2; } catch (NoSuchFieldError ex) {}
     *              }
     *          }
     *
* class EnumMapping provides mapping data and support methods for this translation. */ class EnumMapping { EnumMapping(DiagnosticPosition pos, TypeSymbol forEnum) { this.forEnum = forEnum; this.values = new LinkedHashMap<>(); this.pos = pos; Name varName = names .fromString(target.syntheticNameChar() + "SwitchMap" + target.syntheticNameChar() + writer.xClassName(forEnum.type).toString() .replace('/', '.') .replace('.', target.syntheticNameChar())); ClassSymbol outerCacheClass = outerCacheClass(); this.mapVar = new VarSymbol(STATIC | SYNTHETIC | FINAL, varName, new ArrayType(syms.intType, syms.arrayClass), outerCacheClass); enterSynthetic(pos, mapVar, outerCacheClass.members()); } DiagnosticPosition pos = null; // the next value to use int next = 1; // 0 (unused map elements) go to the default label // the enum for which this is a map final TypeSymbol forEnum; // the field containing the map final VarSymbol mapVar; // the mapped values final Map values; JCLiteral forConstant(VarSymbol v) { Integer result = values.get(v); if (result == null) values.put(v, result = next++); return make.Literal(result); } // generate the field initializer for the map void translate() { make.at(pos.getStartPosition()); JCClassDecl owner = classDef((ClassSymbol)mapVar.owner); // synthetic static final int[] $SwitchMap$Color = new int[Color.values().length]; MethodSymbol valuesMethod = lookupMethod(pos, names.values, forEnum.type, List.nil()); JCExpression size = make // Color.values().length .Select(make.App(make.QualIdent(valuesMethod)), syms.lengthVar); JCExpression mapVarInit = make .NewArray(make.Type(syms.intType), List.of(size), null) .setType(new ArrayType(syms.intType, syms.arrayClass)); // try { $SwitchMap$Color[red.ordinal()] = 1; } catch (java.lang.NoSuchFieldError ex) {} ListBuffer stmts = new ListBuffer<>(); Symbol ordinalMethod = lookupMethod(pos, names.ordinal, forEnum.type, List.nil()); List catcher = List.nil() .prepend(make.Catch(make.VarDef(new VarSymbol(PARAMETER, names.ex, syms.noSuchFieldErrorType, syms.noSymbol), null), make.Block(0, List.nil()))); for (Map.Entry e : values.entrySet()) { VarSymbol enumerator = e.getKey(); Integer mappedValue = e.getValue(); JCExpression assign = make .Assign(make.Indexed(mapVar, make.App(make.Select(make.QualIdent(enumerator), ordinalMethod))), make.Literal(mappedValue)) .setType(syms.intType); JCStatement exec = make.Exec(assign); JCStatement _try = make.Try(make.Block(0, List.of(exec)), catcher, null); stmts.append(_try); } owner.defs = owner.defs .prepend(make.Block(STATIC, stmts.toList())) .prepend(make.VarDef(mapVar, mapVarInit)); } } /************************************************************************** * Tree building blocks *************************************************************************/ /** Equivalent to make.at(pos.getStartPosition()) with side effect of caching * pos as make_pos, for use in diagnostics. **/ TreeMaker make_at(DiagnosticPosition pos) { make_pos = pos; return make.at(pos); } /** Make an attributed tree representing a literal. This will be an * Ident node in the case of boolean literals, a Literal node in all * other cases. * @param type The literal's type. * @param value The literal's value. */ JCExpression makeLit(Type type, Object value) { return make.Literal(type.getTag(), value).setType(type.constType(value)); } /** Make an attributed tree representing null. */ JCExpression makeNull() { return makeLit(syms.botType, null); } /** Make an attributed class instance creation expression. * @param ctype The class type. * @param args The constructor arguments. */ JCNewClass makeNewClass(Type ctype, List args) { JCNewClass tree = make.NewClass(null, null, make.QualIdent(ctype.tsym), args, null); tree.constructor = rs.resolveConstructor( make_pos, attrEnv, ctype, TreeInfo.types(args), List.nil()); tree.type = ctype; return tree; } /** Make an attributed unary expression. * @param optag The operators tree tag. * @param arg The operator's argument. */ JCUnary makeUnary(JCTree.Tag optag, JCExpression arg) { JCUnary tree = make.Unary(optag, arg); tree.operator = operators.resolveUnary(tree, optag, arg.type); tree.type = tree.operator.type.getReturnType(); return tree; } /** Make an attributed binary expression. * @param optag The operators tree tag. * @param lhs The operator's left argument. * @param rhs The operator's right argument. */ JCBinary makeBinary(JCTree.Tag optag, JCExpression lhs, JCExpression rhs) { JCBinary tree = make.Binary(optag, lhs, rhs); tree.operator = operators.resolveBinary(tree, optag, lhs.type, rhs.type); tree.type = tree.operator.type.getReturnType(); return tree; } /** Make an attributed assignop expression. * @param optag The operators tree tag. * @param lhs The operator's left argument. * @param rhs The operator's right argument. */ JCAssignOp makeAssignop(JCTree.Tag optag, JCTree lhs, JCTree rhs) { JCAssignOp tree = make.Assignop(optag, lhs, rhs); tree.operator = operators.resolveBinary(tree, tree.getTag().noAssignOp(), lhs.type, rhs.type); tree.type = lhs.type; return tree; } /** Convert tree into string object, unless it has already a * reference type.. */ JCExpression makeString(JCExpression tree) { if (!tree.type.isPrimitiveOrVoid()) { return tree; } else { Symbol valueOfSym = lookupMethod(tree.pos(), names.valueOf, syms.stringType, List.of(tree.type)); return make.App(make.QualIdent(valueOfSym), List.of(tree)); } } /** Create an empty anonymous class definition and enter and complete * its symbol. Return the class definition's symbol. * and create * @param flags The class symbol's flags * @param owner The class symbol's owner */ JCClassDecl makeEmptyClass(long flags, ClassSymbol owner) { return makeEmptyClass(flags, owner, null, true); } JCClassDecl makeEmptyClass(long flags, ClassSymbol owner, Name flatname, boolean addToDefs) { // Create class symbol. ClassSymbol c = syms.defineClass(names.empty, owner); if (flatname != null) { c.flatname = flatname; } else { c.flatname = chk.localClassName(c); } c.sourcefile = owner.sourcefile; c.completer = Completer.NULL_COMPLETER; c.members_field = WriteableScope.create(c); c.flags_field = flags; ClassType ctype = (ClassType) c.type; ctype.supertype_field = syms.objectType; ctype.interfaces_field = List.nil(); JCClassDecl odef = classDef(owner); // Enter class symbol in owner scope and compiled table. enterSynthetic(odef.pos(), c, owner.members()); chk.putCompiled(c); // Create class definition tree. JCClassDecl cdef = make.ClassDef( make.Modifiers(flags), names.empty, List.nil(), null, List.nil(), List.nil()); cdef.sym = c; cdef.type = c.type; // Append class definition tree to owner's definitions. if (addToDefs) odef.defs = odef.defs.prepend(cdef); return cdef; } /************************************************************************** * Symbol manipulation utilities *************************************************************************/ /** Enter a synthetic symbol in a given scope, but complain if there was already one there. * @param pos Position for error reporting. * @param sym The symbol. * @param s The scope. */ private void enterSynthetic(DiagnosticPosition pos, Symbol sym, WriteableScope s) { s.enter(sym); } /** Create a fresh synthetic name within a given scope - the unique name is * obtained by appending '$' chars at the end of the name until no match * is found. * * @param name base name * @param s scope in which the name has to be unique * @return fresh synthetic name */ private Name makeSyntheticName(Name name, Scope s) { do { name = name.append( target.syntheticNameChar(), names.empty); } while (lookupSynthetic(name, s) != null); return name; } /** Check whether synthetic symbols generated during lowering conflict * with user-defined symbols. * * @param translatedTrees lowered class trees */ void checkConflicts(List translatedTrees) { for (JCTree t : translatedTrees) { t.accept(conflictsChecker); } } JCTree.Visitor conflictsChecker = new TreeScanner() { TypeSymbol currentClass; @Override public void visitMethodDef(JCMethodDecl that) { chk.checkConflicts(that.pos(), that.sym, currentClass); super.visitMethodDef(that); } @Override public void visitVarDef(JCVariableDecl that) { if (that.sym.owner.kind == TYP) { chk.checkConflicts(that.pos(), that.sym, currentClass); } super.visitVarDef(that); } @Override public void visitClassDef(JCClassDecl that) { TypeSymbol prevCurrentClass = currentClass; currentClass = that.sym; try { super.visitClassDef(that); } finally { currentClass = prevCurrentClass; } } }; /** Look up a synthetic name in a given scope. * @param s The scope. * @param name The name. */ private Symbol lookupSynthetic(Name name, Scope s) { Symbol sym = s.findFirst(name); return (sym==null || (sym.flags()&SYNTHETIC)==0) ? null : sym; } /** Look up a method in a given scope. */ private MethodSymbol lookupMethod(DiagnosticPosition pos, Name name, Type qual, List args) { return rs.resolveInternalMethod(pos, attrEnv, qual, name, args, List.nil()); } /** Look up a constructor. */ private MethodSymbol lookupConstructor(DiagnosticPosition pos, Type qual, List args) { return rs.resolveInternalConstructor(pos, attrEnv, qual, args, null); } /** Look up a field. */ private VarSymbol lookupField(DiagnosticPosition pos, Type qual, Name name) { return rs.resolveInternalField(pos, attrEnv, qual, name); } /** Anon inner classes are used as access constructor tags. * accessConstructorTag will use an existing anon class if one is available, * and synthethise a class (with makeEmptyClass) if one is not available. * However, there is a small possibility that an existing class will not * be generated as expected if it is inside a conditional with a constant * expression. If that is found to be the case, create an empty class tree here. */ private void checkAccessConstructorTags() { for (List l = accessConstrTags; l.nonEmpty(); l = l.tail) { ClassSymbol c = l.head; if (isTranslatedClassAvailable(c)) continue; // Create class definition tree. JCClassDecl cdec = makeEmptyClass(STATIC | SYNTHETIC, c.outermostClass(), c.flatname, false); swapAccessConstructorTag(c, cdec.sym); translated.append(cdec); } } // where private boolean isTranslatedClassAvailable(ClassSymbol c) { for (JCTree tree: translated) { if (tree.hasTag(CLASSDEF) && ((JCClassDecl) tree).sym == c) { return true; } } return false; } void swapAccessConstructorTag(ClassSymbol oldCTag, ClassSymbol newCTag) { for (MethodSymbol methodSymbol : accessConstrs.values()) { Assert.check(methodSymbol.type.hasTag(METHOD)); MethodType oldMethodType = (MethodType)methodSymbol.type; if (oldMethodType.argtypes.head.tsym == oldCTag) methodSymbol.type = types.createMethodTypeWithParameters(oldMethodType, oldMethodType.getParameterTypes().tail .prepend(newCTag.erasure(types))); } } /************************************************************************** * Access methods *************************************************************************/ /** A mapping from symbols to their access numbers. */ private Map accessNums; /** A mapping from symbols to an array of access symbols, indexed by * access code. */ private Map accessSyms; /** A mapping from (constructor) symbols to access constructor symbols. */ private Map accessConstrs; /** A list of all class symbols used for access constructor tags. */ private List accessConstrTags; /** A queue for all accessed symbols. */ private ListBuffer accessed; /** return access code for identifier, * @param tree The tree representing the identifier use. * @param enclOp The closest enclosing operation node of tree, * null if tree is not a subtree of an operation. */ private static int accessCode(JCTree tree, JCTree enclOp) { if (enclOp == null) return AccessCode.DEREF.code; else if (enclOp.hasTag(ASSIGN) && tree == TreeInfo.skipParens(((JCAssign) enclOp).lhs)) return AccessCode.ASSIGN.code; else if ((enclOp.getTag().isIncOrDecUnaryOp() || enclOp.getTag().isAssignop()) && tree == TreeInfo.skipParens(((JCOperatorExpression) enclOp).getOperand(LEFT))) return (((JCOperatorExpression) enclOp).operator).getAccessCode(enclOp.getTag()); else return AccessCode.DEREF.code; } /** Return binary operator that corresponds to given access code. */ private OperatorSymbol binaryAccessOperator(int acode, Tag tag) { return operators.lookupBinaryOp(op -> op.getAccessCode(tag) == acode); } /** Return tree tag for assignment operation corresponding * to given binary operator. */ private static JCTree.Tag treeTag(OperatorSymbol operator) { switch (operator.opcode) { case ByteCodes.ior: case ByteCodes.lor: return BITOR_ASG; case ByteCodes.ixor: case ByteCodes.lxor: return BITXOR_ASG; case ByteCodes.iand: case ByteCodes.land: return BITAND_ASG; case ByteCodes.ishl: case ByteCodes.lshl: case ByteCodes.ishll: case ByteCodes.lshll: return SL_ASG; case ByteCodes.ishr: case ByteCodes.lshr: case ByteCodes.ishrl: case ByteCodes.lshrl: return SR_ASG; case ByteCodes.iushr: case ByteCodes.lushr: case ByteCodes.iushrl: case ByteCodes.lushrl: return USR_ASG; case ByteCodes.iadd: case ByteCodes.ladd: case ByteCodes.fadd: case ByteCodes.dadd: case ByteCodes.string_add: return PLUS_ASG; case ByteCodes.isub: case ByteCodes.lsub: case ByteCodes.fsub: case ByteCodes.dsub: return MINUS_ASG; case ByteCodes.imul: case ByteCodes.lmul: case ByteCodes.fmul: case ByteCodes.dmul: return MUL_ASG; case ByteCodes.idiv: case ByteCodes.ldiv: case ByteCodes.fdiv: case ByteCodes.ddiv: return DIV_ASG; case ByteCodes.imod: case ByteCodes.lmod: case ByteCodes.fmod: case ByteCodes.dmod: return MOD_ASG; default: throw new AssertionError(); } } /** The name of the access method with number `anum' and access code `acode'. */ Name accessName(int anum, int acode) { return names.fromString( "access" + target.syntheticNameChar() + anum + acode / 10 + acode % 10); } /** Return access symbol for a private or protected symbol from an inner class. * @param sym The accessed private symbol. * @param tree The accessing tree. * @param enclOp The closest enclosing operation node of tree, * null if tree is not a subtree of an operation. * @param protAccess Is access to a protected symbol in another * package? * @param refSuper Is access via a (qualified) C.super? */ MethodSymbol accessSymbol(Symbol sym, JCTree tree, JCTree enclOp, boolean protAccess, boolean refSuper) { ClassSymbol accOwner = refSuper && protAccess // For access via qualified super (T.super.x), place the // access symbol on T. ? (ClassSymbol)((JCFieldAccess) tree).selected.type.tsym // Otherwise pretend that the owner of an accessed // protected symbol is the enclosing class of the current // class which is a subclass of the symbol's owner. : accessClass(sym, protAccess, tree); Symbol vsym = sym; if (sym.owner != accOwner) { vsym = sym.clone(accOwner); actualSymbols.put(vsym, sym); } Integer anum // The access number of the access method. = accessNums.get(vsym); if (anum == null) { anum = accessed.length(); accessNums.put(vsym, anum); accessSyms.put(vsym, new MethodSymbol[AccessCode.numberOfAccessCodes]); accessed.append(vsym); // System.out.println("accessing " + vsym + " in " + vsym.location()); } int acode; // The access code of the access method. List argtypes; // The argument types of the access method. Type restype; // The result type of the access method. List thrown; // The thrown exceptions of the access method. switch (vsym.kind) { case VAR: acode = accessCode(tree, enclOp); if (acode >= AccessCode.FIRSTASGOP.code) { OperatorSymbol operator = binaryAccessOperator(acode, enclOp.getTag()); if (operator.opcode == string_add) argtypes = List.of(syms.objectType); else argtypes = operator.type.getParameterTypes().tail; } else if (acode == AccessCode.ASSIGN.code) argtypes = List.of(vsym.erasure(types)); else argtypes = List.nil(); restype = vsym.erasure(types); thrown = List.nil(); break; case MTH: acode = AccessCode.DEREF.code; argtypes = vsym.erasure(types).getParameterTypes(); restype = vsym.erasure(types).getReturnType(); thrown = vsym.type.getThrownTypes(); break; default: throw new AssertionError(); } // For references via qualified super, increment acode by one, // making it odd. if (protAccess && refSuper) acode++; // Instance access methods get instance as first parameter. // For protected symbols this needs to be the instance as a member // of the type containing the accessed symbol, not the class // containing the access method. if ((vsym.flags() & STATIC) == 0) { argtypes = argtypes.prepend(vsym.owner.erasure(types)); } MethodSymbol[] accessors = accessSyms.get(vsym); MethodSymbol accessor = accessors[acode]; if (accessor == null) { accessor = new MethodSymbol( STATIC | SYNTHETIC | (accOwner.isInterface() ? PUBLIC : 0), accessName(anum.intValue(), acode), new MethodType(argtypes, restype, thrown, syms.methodClass), accOwner); enterSynthetic(tree.pos(), accessor, accOwner.members()); accessors[acode] = accessor; } return accessor; } /** The qualifier to be used for accessing a symbol in an outer class. * This is either C.sym or C.this.sym, depending on whether or not * sym is static. * @param sym The accessed symbol. */ JCExpression accessBase(DiagnosticPosition pos, Symbol sym) { return (sym.flags() & STATIC) != 0 ? access(make.at(pos.getStartPosition()).QualIdent(sym.owner)) : makeOwnerThis(pos, sym, true); } /** Do we need an access method to reference private symbol? */ boolean needsPrivateAccess(Symbol sym) { if ((sym.flags() & PRIVATE) == 0 || sym.owner == currentClass) { return false; } else if (sym.name == names.init && sym.owner.isLocal()) { // private constructor in local class: relax protection sym.flags_field &= ~PRIVATE; return false; } else { return true; } } /** Do we need an access method to reference symbol in other package? */ boolean needsProtectedAccess(Symbol sym, JCTree tree) { if ((sym.flags() & PROTECTED) == 0 || sym.owner.owner == currentClass.owner || // fast special case sym.packge() == currentClass.packge()) return false; if (!currentClass.isSubClass(sym.owner, types)) return true; if ((sym.flags() & STATIC) != 0 || !tree.hasTag(SELECT) || TreeInfo.name(((JCFieldAccess) tree).selected) == names._super) return false; return !((JCFieldAccess) tree).selected.type.tsym.isSubClass(currentClass, types); } /** The class in which an access method for given symbol goes. * @param sym The access symbol * @param protAccess Is access to a protected symbol in another * package? */ ClassSymbol accessClass(Symbol sym, boolean protAccess, JCTree tree) { if (protAccess) { Symbol qualifier = null; ClassSymbol c = currentClass; if (tree.hasTag(SELECT) && (sym.flags() & STATIC) == 0) { qualifier = ((JCFieldAccess) tree).selected.type.tsym; while (!qualifier.isSubClass(c, types)) { c = c.owner.enclClass(); } return c; } else { while (!c.isSubClass(sym.owner, types)) { c = c.owner.enclClass(); } } return c; } else { // the symbol is private return sym.owner.enclClass(); } } private void addPrunedInfo(JCTree tree) { List infoList = prunedTree.get(currentClass); infoList = (infoList == null) ? List.of(tree) : infoList.prepend(tree); prunedTree.put(currentClass, infoList); } /** Ensure that identifier is accessible, return tree accessing the identifier. * @param sym The accessed symbol. * @param tree The tree referring to the symbol. * @param enclOp The closest enclosing operation node of tree, * null if tree is not a subtree of an operation. * @param refSuper Is access via a (qualified) C.super? */ JCExpression access(Symbol sym, JCExpression tree, JCExpression enclOp, boolean refSuper) { // Access a free variable via its proxy, or its proxy's proxy while (sym.kind == VAR && sym.owner.kind == MTH && sym.owner.enclClass() != currentClass) { // A constant is replaced by its constant value. Object cv = ((VarSymbol)sym).getConstValue(); if (cv != null) { make.at(tree.pos); return makeLit(sym.type, cv); } // Otherwise replace the variable by its proxy. sym = proxies.findFirst(proxyName(sym.name)); Assert.check(sym != null && (sym.flags_field & FINAL) != 0); tree = make.at(tree.pos).Ident(sym); } JCExpression base = (tree.hasTag(SELECT)) ? ((JCFieldAccess) tree).selected : null; switch (sym.kind) { case TYP: if (sym.owner.kind != PCK) { // Convert type idents to // or . Name flatname = Convert.shortName(sym.flatName()); while (base != null && TreeInfo.symbol(base) != null && TreeInfo.symbol(base).kind != PCK) { base = (base.hasTag(SELECT)) ? ((JCFieldAccess) base).selected : null; } if (tree.hasTag(IDENT)) { ((JCIdent) tree).name = flatname; } else if (base == null) { tree = make.at(tree.pos).Ident(sym); ((JCIdent) tree).name = flatname; } else { ((JCFieldAccess) tree).selected = base; ((JCFieldAccess) tree).name = flatname; } } break; case MTH: case VAR: if (sym.owner.kind == TYP) { // Access methods are required for // - private members, // - protected members in a superclass of an // enclosing class contained in another package. // - all non-private members accessed via a qualified super. boolean protAccess = refSuper && !needsPrivateAccess(sym) || needsProtectedAccess(sym, tree); boolean accReq = protAccess || needsPrivateAccess(sym); // A base has to be supplied for // - simple identifiers accessing variables in outer classes. boolean baseReq = base == null && sym.owner != syms.predefClass && !sym.isMemberOf(currentClass, types); if (accReq || baseReq) { make.at(tree.pos); // Constants are replaced by their constant value. if (sym.kind == VAR) { Object cv = ((VarSymbol)sym).getConstValue(); if (cv != null) { addPrunedInfo(tree); return makeLit(sym.type, cv); } } // Private variables and methods are replaced by calls // to their access methods. if (accReq) { List args = List.nil(); if ((sym.flags() & STATIC) == 0) { // Instance access methods get instance // as first parameter. if (base == null) base = makeOwnerThis(tree.pos(), sym, true); args = args.prepend(base); base = null; // so we don't duplicate code } Symbol access = accessSymbol(sym, tree, enclOp, protAccess, refSuper); JCExpression receiver = make.Select( base != null ? base : make.QualIdent(access.owner), access); return make.App(receiver, args); // Other accesses to members of outer classes get a // qualifier. } else if (baseReq) { return make.at(tree.pos).Select( accessBase(tree.pos(), sym), sym).setType(tree.type); } } } else if (sym.owner.kind == MTH && lambdaTranslationMap != null) { //sym is a local variable - check the lambda translation map to //see if sym has been translated to something else in the current //scope (by LambdaToMethod) Symbol translatedSym = lambdaTranslationMap.get(sym); if (translatedSym != null) { tree = make.at(tree.pos).Ident(translatedSym); } } } return tree; } /** Ensure that identifier is accessible, return tree accessing the identifier. * @param tree The identifier tree. */ JCExpression access(JCExpression tree) { Symbol sym = TreeInfo.symbol(tree); return sym == null ? tree : access(sym, tree, null, false); } /** Return access constructor for a private constructor, * or the constructor itself, if no access constructor is needed. * @param pos The position to report diagnostics, if any. * @param constr The private constructor. */ Symbol accessConstructor(DiagnosticPosition pos, Symbol constr) { if (needsPrivateAccess(constr)) { ClassSymbol accOwner = constr.owner.enclClass(); MethodSymbol aconstr = accessConstrs.get(constr); if (aconstr == null) { List argtypes = constr.type.getParameterTypes(); if ((accOwner.flags_field & ENUM) != 0) argtypes = argtypes .prepend(syms.intType) .prepend(syms.stringType); aconstr = new MethodSymbol( SYNTHETIC, names.init, new MethodType( argtypes.append( accessConstructorTag().erasure(types)), constr.type.getReturnType(), constr.type.getThrownTypes(), syms.methodClass), accOwner); enterSynthetic(pos, aconstr, accOwner.members()); accessConstrs.put(constr, aconstr); accessed.append(constr); } return aconstr; } else { return constr; } } /** Return an anonymous class nested in this toplevel class. */ ClassSymbol accessConstructorTag() { ClassSymbol topClass = currentClass.outermostClass(); ModuleSymbol topModle = topClass.packge().modle; Name flatname = names.fromString("" + topClass.getQualifiedName() + target.syntheticNameChar() + "1"); ClassSymbol ctag = chk.getCompiled(topModle, flatname); if (ctag == null) ctag = makeEmptyClass(STATIC | SYNTHETIC, topClass).sym; // keep a record of all tags, to verify that all are generated as required accessConstrTags = accessConstrTags.prepend(ctag); return ctag; } /** Add all required access methods for a private symbol to enclosing class. * @param sym The symbol. */ void makeAccessible(Symbol sym) { JCClassDecl cdef = classDef(sym.owner.enclClass()); if (cdef == null) Assert.error("class def not found: " + sym + " in " + sym.owner); if (sym.name == names.init) { cdef.defs = cdef.defs.prepend( accessConstructorDef(cdef.pos, sym, accessConstrs.get(sym))); } else { MethodSymbol[] accessors = accessSyms.get(sym); for (int i = 0; i < AccessCode.numberOfAccessCodes; i++) { if (accessors[i] != null) cdef.defs = cdef.defs.prepend( accessDef(cdef.pos, sym, accessors[i], i)); } } } /** Construct definition of an access method. * @param pos The source code position of the definition. * @param vsym The private or protected symbol. * @param accessor The access method for the symbol. * @param acode The access code. */ JCTree accessDef(int pos, Symbol vsym, MethodSymbol accessor, int acode) { // System.err.println("access " + vsym + " with " + accessor);//DEBUG currentClass = vsym.owner.enclClass(); make.at(pos); JCMethodDecl md = make.MethodDef(accessor, null); // Find actual symbol Symbol sym = actualSymbols.get(vsym); if (sym == null) sym = vsym; JCExpression ref; // The tree referencing the private symbol. List args; // Any additional arguments to be passed along. if ((sym.flags() & STATIC) != 0) { ref = make.Ident(sym); args = make.Idents(md.params); } else { JCExpression site = make.Ident(md.params.head); if (acode % 2 != 0) { //odd access codes represent qualified super accesses - need to //emit reference to the direct superclass, even if the refered //member is from an indirect superclass (JLS 13.1) site.setType(types.erasure(types.supertype(vsym.owner.enclClass().type))); } ref = make.Select(site, sym); args = make.Idents(md.params.tail); } JCStatement stat; // The statement accessing the private symbol. if (sym.kind == VAR) { // Normalize out all odd access codes by taking floor modulo 2: int acode1 = acode - (acode & 1); JCExpression expr; // The access method's return value. AccessCode aCode = AccessCode.getFromCode(acode1); switch (aCode) { case DEREF: expr = ref; break; case ASSIGN: expr = make.Assign(ref, args.head); break; case PREINC: case POSTINC: case PREDEC: case POSTDEC: expr = makeUnary(aCode.tag, ref); break; default: expr = make.Assignop( treeTag(binaryAccessOperator(acode1, JCTree.Tag.NO_TAG)), ref, args.head); ((JCAssignOp) expr).operator = binaryAccessOperator(acode1, JCTree.Tag.NO_TAG); } stat = make.Return(expr.setType(sym.type)); } else { stat = make.Call(make.App(ref, args)); } md.body = make.Block(0, List.of(stat)); // Make sure all parameters, result types and thrown exceptions // are accessible. for (List l = md.params; l.nonEmpty(); l = l.tail) l.head.vartype = access(l.head.vartype); md.restype = access(md.restype); for (List l = md.thrown; l.nonEmpty(); l = l.tail) l.head = access(l.head); return md; } /** Construct definition of an access constructor. * @param pos The source code position of the definition. * @param constr The private constructor. * @param accessor The access method for the constructor. */ JCTree accessConstructorDef(int pos, Symbol constr, MethodSymbol accessor) { make.at(pos); JCMethodDecl md = make.MethodDef(accessor, accessor.externalType(types), null); JCIdent callee = make.Ident(names._this); callee.sym = constr; callee.type = constr.type; md.body = make.Block(0, List.of( make.Call( make.App( callee, make.Idents(md.params.reverse().tail.reverse()))))); return md; } /************************************************************************** * Free variables proxies and this$n *************************************************************************/ /** A scope containing all free variable proxies for currently translated * class, as well as its this$n symbol (if needed). * Proxy scopes are nested in the same way classes are. * Inside a constructor, proxies and any this$n symbol are duplicated * in an additional innermost scope, where they represent the constructor * parameters. */ WriteableScope proxies; /** A scope containing all unnamed resource variables/saved * exception variables for translated TWR blocks */ WriteableScope twrVars; /** A stack containing the this$n field of the currently translated * classes (if needed) in innermost first order. * Inside a constructor, proxies and any this$n symbol are duplicated * in an additional innermost scope, where they represent the constructor * parameters. */ List outerThisStack; /** The name of a free variable proxy. */ Name proxyName(Name name) { return names.fromString("val" + target.syntheticNameChar() + name); } /** Proxy definitions for all free variables in given list, in reverse order. * @param pos The source code position of the definition. * @param freevars The free variables. * @param owner The class in which the definitions go. */ List freevarDefs(int pos, List freevars, Symbol owner) { return freevarDefs(pos, freevars, owner, 0); } List freevarDefs(int pos, List freevars, Symbol owner, long additionalFlags) { long flags = FINAL | SYNTHETIC | additionalFlags; List defs = List.nil(); for (List l = freevars; l.nonEmpty(); l = l.tail) { VarSymbol v = l.head; VarSymbol proxy = new VarSymbol( flags, proxyName(v.name), v.erasure(types), owner); proxies.enter(proxy); JCVariableDecl vd = make.at(pos).VarDef(proxy, null); vd.vartype = access(vd.vartype); defs = defs.prepend(vd); } return defs; } /** The name of a this$n field * @param type The class referenced by the this$n field */ Name outerThisName(Type type, Symbol owner) { Type t = type.getEnclosingType(); int nestingLevel = 0; while (t.hasTag(CLASS)) { t = t.getEnclosingType(); nestingLevel++; } Name result = names.fromString("this" + target.syntheticNameChar() + nestingLevel); while (owner.kind == TYP && ((ClassSymbol)owner).members().findFirst(result) != null) result = names.fromString(result.toString() + target.syntheticNameChar()); return result; } private VarSymbol makeOuterThisVarSymbol(Symbol owner, long flags) { Type target = types.erasure(owner.enclClass().type.getEnclosingType()); VarSymbol outerThis = new VarSymbol(flags, outerThisName(target, owner), target, owner); outerThisStack = outerThisStack.prepend(outerThis); return outerThis; } private JCVariableDecl makeOuterThisVarDecl(int pos, VarSymbol sym) { JCVariableDecl vd = make.at(pos).VarDef(sym, null); vd.vartype = access(vd.vartype); return vd; } /** Definition for this$n field. * @param pos The source code position of the definition. * @param owner The method in which the definition goes. */ JCVariableDecl outerThisDef(int pos, MethodSymbol owner) { ClassSymbol c = owner.enclClass(); boolean isMandated = // Anonymous constructors (owner.isConstructor() && owner.isAnonymous()) || // Constructors of non-private inner member classes (owner.isConstructor() && c.isInner() && !c.isPrivate() && !c.isStatic()); long flags = FINAL | (isMandated ? MANDATED : SYNTHETIC) | PARAMETER; VarSymbol outerThis = makeOuterThisVarSymbol(owner, flags); owner.extraParams = owner.extraParams.prepend(outerThis); return makeOuterThisVarDecl(pos, outerThis); } /** Definition for this$n field. * @param pos The source code position of the definition. * @param owner The class in which the definition goes. */ JCVariableDecl outerThisDef(int pos, ClassSymbol owner) { VarSymbol outerThis = makeOuterThisVarSymbol(owner, FINAL | SYNTHETIC); return makeOuterThisVarDecl(pos, outerThis); } /** Return a list of trees that load the free variables in given list, * in reverse order. * @param pos The source code position to be used for the trees. * @param freevars The list of free variables. */ List loadFreevars(DiagnosticPosition pos, List freevars) { List args = List.nil(); for (List l = freevars; l.nonEmpty(); l = l.tail) args = args.prepend(loadFreevar(pos, l.head)); return args; } //where JCExpression loadFreevar(DiagnosticPosition pos, VarSymbol v) { return access(v, make.at(pos).Ident(v), null, false); } /** Construct a tree simulating the expression {@code C.this}. * @param pos The source code position to be used for the tree. * @param c The qualifier class. */ JCExpression makeThis(DiagnosticPosition pos, TypeSymbol c) { if (currentClass == c) { // in this case, `this' works fine return make.at(pos).This(c.erasure(types)); } else { // need to go via this$n return makeOuterThis(pos, c); } } /** * Optionally replace a try statement with the desugaring of a * try-with-resources statement. The canonical desugaring of * * try ResourceSpecification * Block * * is * * { * final VariableModifiers_minus_final R #resource = Expression; * Throwable #primaryException = null; * * try ResourceSpecificationtail * Block * catch (Throwable #t) { * #primaryException = t; * throw #t; * } finally { * if (#resource != null) { * if (#primaryException != null) { * try { * #resource.close(); * } catch(Throwable #suppressedException) { * #primaryException.addSuppressed(#suppressedException); * } * } else { * #resource.close(); * } * } * } * * @param tree The try statement to inspect. * @return A a desugared try-with-resources tree, or the original * try block if there are no resources to manage. */ JCTree makeTwrTry(JCTry tree) { make_at(tree.pos()); twrVars = twrVars.dup(); JCBlock twrBlock = makeTwrBlock(tree.resources, tree.body, tree.finallyCanCompleteNormally, 0); if (tree.catchers.isEmpty() && tree.finalizer == null) result = translate(twrBlock); else result = translate(make.Try(twrBlock, tree.catchers, tree.finalizer)); twrVars = twrVars.leave(); return result; } private JCBlock makeTwrBlock(List resources, JCBlock block, boolean finallyCanCompleteNormally, int depth) { if (resources.isEmpty()) return block; // Add resource declaration or expression to block statements ListBuffer stats = new ListBuffer<>(); JCTree resource = resources.head; JCExpression expr = null; boolean resourceNonNull; if (resource instanceof JCVariableDecl) { JCVariableDecl var = (JCVariableDecl) resource; expr = make.Ident(var.sym).setType(resource.type); resourceNonNull = var.init != null && TreeInfo.skipParens(var.init).hasTag(NEWCLASS); stats.add(var); } else { Assert.check(resource instanceof JCExpression); VarSymbol syntheticTwrVar = new VarSymbol(SYNTHETIC | FINAL, makeSyntheticName(names.fromString("twrVar" + depth), twrVars), (resource.type.hasTag(BOT)) ? syms.autoCloseableType : resource.type, currentMethodSym); twrVars.enter(syntheticTwrVar); JCVariableDecl syntheticTwrVarDecl = make.VarDef(syntheticTwrVar, (JCExpression)resource); expr = (JCExpression)make.Ident(syntheticTwrVar); resourceNonNull = TreeInfo.skipParens(resource).hasTag(NEWCLASS); stats.add(syntheticTwrVarDecl); } // Add primaryException declaration VarSymbol primaryException = new VarSymbol(SYNTHETIC, makeSyntheticName(names.fromString("primaryException" + depth), twrVars), syms.throwableType, currentMethodSym); twrVars.enter(primaryException); JCVariableDecl primaryExceptionTreeDecl = make.VarDef(primaryException, makeNull()); stats.add(primaryExceptionTreeDecl); // Create catch clause that saves exception and then rethrows it VarSymbol param = new VarSymbol(FINAL|SYNTHETIC, names.fromString("t" + target.syntheticNameChar()), syms.throwableType, currentMethodSym); JCVariableDecl paramTree = make.VarDef(param, null); JCStatement assign = make.Assignment(primaryException, make.Ident(param)); JCStatement rethrowStat = make.Throw(make.Ident(param)); JCBlock catchBlock = make.Block(0L, List.of(assign, rethrowStat)); JCCatch catchClause = make.Catch(paramTree, catchBlock); int oldPos = make.pos; make.at(TreeInfo.endPos(block)); JCBlock finallyClause = makeTwrFinallyClause(primaryException, expr, resourceNonNull); make.at(oldPos); JCTry outerTry = make.Try(makeTwrBlock(resources.tail, block, finallyCanCompleteNormally, depth + 1), List.of(catchClause), finallyClause); outerTry.finallyCanCompleteNormally = finallyCanCompleteNormally; stats.add(outerTry); JCBlock newBlock = make.Block(0L, stats.toList()); return newBlock; } /**If the estimated number of copies the close resource code in a single class is above this * threshold, generate and use a method for the close resource code, leading to smaller code. * As generating a method has overhead on its own, generating the method for cases below the * threshold could lead to an increase in code size. */ public static final int USE_CLOSE_RESOURCE_METHOD_THRESHOLD = 4; private JCBlock makeTwrFinallyClause(Symbol primaryException, JCExpression resource, boolean resourceNonNull) { MethodSymbol closeResource = (MethodSymbol)lookupSynthetic(dollarCloseResource, currentClass.members()); if (closeResource == null && shouldUseCloseResourceMethod()) { closeResource = new MethodSymbol( PRIVATE | STATIC | SYNTHETIC, dollarCloseResource, new MethodType( List.of(syms.throwableType, syms.autoCloseableType), syms.voidType, List.nil(), syms.methodClass), currentClass); enterSynthetic(resource.pos(), closeResource, currentClass.members()); JCMethodDecl md = make.MethodDef(closeResource, null); List params = md.getParameters(); md.body = make.Block(0, List.of(makeTwrCloseStatement(params.get(0).sym, make.Ident(params.get(1))))); JCClassDecl currentClassDecl = classDef(currentClass); currentClassDecl.defs = currentClassDecl.defs.prepend(md); } JCStatement closeStatement; if (closeResource != null) { //$closeResource(#primaryException, #resource) closeStatement = make.Exec(make.Apply(List.nil(), make.Ident(closeResource), List.of(make.Ident(primaryException), resource) ).setType(syms.voidType)); } else { closeStatement = makeTwrCloseStatement(primaryException, resource); } JCStatement finallyStatement; if (resourceNonNull) { finallyStatement = closeStatement; } else { // if (#resource != null) { $closeResource(...); } finallyStatement = make.If(makeNonNullCheck(resource), closeStatement, null); } return make.Block(0L, List.of(finallyStatement)); } //where: private boolean shouldUseCloseResourceMethod() { class TryFinder extends TreeScanner { int closeCount; @Override public void visitTry(JCTry tree) { boolean empty = tree.body.stats.isEmpty(); for (JCTree r : tree.resources) { closeCount += empty ? 1 : 2; empty = false; //with multiple resources, only the innermost try can be empty. } super.visitTry(tree); } @Override public void scan(JCTree tree) { if (useCloseResourceMethod()) return; super.scan(tree); } boolean useCloseResourceMethod() { return closeCount >= USE_CLOSE_RESOURCE_METHOD_THRESHOLD; } } TryFinder tryFinder = new TryFinder(); tryFinder.scan(classDef(currentClass)); return tryFinder.useCloseResourceMethod(); } private JCStatement makeTwrCloseStatement(Symbol primaryException, JCExpression resource) { // primaryException.addSuppressed(catchException); VarSymbol catchException = new VarSymbol(SYNTHETIC, make.paramName(2), syms.throwableType, currentMethodSym); JCStatement addSuppressionStatement = make.Exec(makeCall(make.Ident(primaryException), names.addSuppressed, List.of(make.Ident(catchException)))); // try { resource.close(); } catch (e) { primaryException.addSuppressed(e); } JCBlock tryBlock = make.Block(0L, List.of(makeResourceCloseInvocation(resource))); JCVariableDecl catchExceptionDecl = make.VarDef(catchException, null); JCBlock catchBlock = make.Block(0L, List.of(addSuppressionStatement)); List catchClauses = List.of(make.Catch(catchExceptionDecl, catchBlock)); JCTry tryTree = make.Try(tryBlock, catchClauses, null); tryTree.finallyCanCompleteNormally = true; // if (primaryException != null) {try...} else resourceClose; JCIf closeIfStatement = make.If(makeNonNullCheck(make.Ident(primaryException)), tryTree, makeResourceCloseInvocation(resource)); return closeIfStatement; } private JCStatement makeResourceCloseInvocation(JCExpression resource) { // convert to AutoCloseable if needed if (types.asSuper(resource.type, syms.autoCloseableType.tsym) == null) { resource = convert(resource, syms.autoCloseableType); } // create resource.close() method invocation JCExpression resourceClose = makeCall(resource, names.close, List.nil()); return make.Exec(resourceClose); } private JCExpression makeNonNullCheck(JCExpression expression) { return makeBinary(NE, expression, makeNull()); } /** Construct a tree that represents the outer instance * {@code C.this}. Never pick the current `this'. * @param pos The source code position to be used for the tree. * @param c The qualifier class. */ JCExpression makeOuterThis(DiagnosticPosition pos, TypeSymbol c) { List ots = outerThisStack; if (ots.isEmpty()) { log.error(pos, "no.encl.instance.of.type.in.scope", c); Assert.error(); return makeNull(); } VarSymbol ot = ots.head; JCExpression tree = access(make.at(pos).Ident(ot)); TypeSymbol otc = ot.type.tsym; while (otc != c) { do { ots = ots.tail; if (ots.isEmpty()) { log.error(pos, "no.encl.instance.of.type.in.scope", c); Assert.error(); // should have been caught in Attr return tree; } ot = ots.head; } while (ot.owner != otc); if (otc.owner.kind != PCK && !otc.hasOuterInstance()) { chk.earlyRefError(pos, c); Assert.error(); // should have been caught in Attr return makeNull(); } tree = access(make.at(pos).Select(tree, ot)); otc = ot.type.tsym; } return tree; } /** Construct a tree that represents the closest outer instance * {@code C.this} such that the given symbol is a member of C. * @param pos The source code position to be used for the tree. * @param sym The accessed symbol. * @param preciseMatch should we accept a type that is a subtype of * sym's owner, even if it doesn't contain sym * due to hiding, overriding, or non-inheritance * due to protection? */ JCExpression makeOwnerThis(DiagnosticPosition pos, Symbol sym, boolean preciseMatch) { Symbol c = sym.owner; if (preciseMatch ? sym.isMemberOf(currentClass, types) : currentClass.isSubClass(sym.owner, types)) { // in this case, `this' works fine return make.at(pos).This(c.erasure(types)); } else { // need to go via this$n return makeOwnerThisN(pos, sym, preciseMatch); } } /** * Similar to makeOwnerThis but will never pick "this". */ JCExpression makeOwnerThisN(DiagnosticPosition pos, Symbol sym, boolean preciseMatch) { Symbol c = sym.owner; List ots = outerThisStack; if (ots.isEmpty()) { log.error(pos, "no.encl.instance.of.type.in.scope", c); Assert.error(); return makeNull(); } VarSymbol ot = ots.head; JCExpression tree = access(make.at(pos).Ident(ot)); TypeSymbol otc = ot.type.tsym; while (!(preciseMatch ? sym.isMemberOf(otc, types) : otc.isSubClass(sym.owner, types))) { do { ots = ots.tail; if (ots.isEmpty()) { log.error(pos, "no.encl.instance.of.type.in.scope", c); Assert.error(); return tree; } ot = ots.head; } while (ot.owner != otc); tree = access(make.at(pos).Select(tree, ot)); otc = ot.type.tsym; } return tree; } /** Return tree simulating the assignment {@code this.name = name}, where * name is the name of a free variable. */ JCStatement initField(int pos, Name name) { Iterator it = proxies.getSymbolsByName(name).iterator(); Symbol rhs = it.next(); Assert.check(rhs.owner.kind == MTH); Symbol lhs = it.next(); Assert.check(rhs.owner.owner == lhs.owner); make.at(pos); return make.Exec( make.Assign( make.Select(make.This(lhs.owner.erasure(types)), lhs), make.Ident(rhs)).setType(lhs.erasure(types))); } /** Return tree simulating the assignment {@code this.this$n = this$n}. */ JCStatement initOuterThis(int pos) { VarSymbol rhs = outerThisStack.head; Assert.check(rhs.owner.kind == MTH); VarSymbol lhs = outerThisStack.tail.head; Assert.check(rhs.owner.owner == lhs.owner); make.at(pos); return make.Exec( make.Assign( make.Select(make.This(lhs.owner.erasure(types)), lhs), make.Ident(rhs)).setType(lhs.erasure(types))); } /************************************************************************** * Code for .class *************************************************************************/ /** Return the symbol of a class to contain a cache of * compiler-generated statics such as class$ and the * $assertionsDisabled flag. We create an anonymous nested class * (unless one already exists) and return its symbol. However, * for backward compatibility in 1.4 and earlier we use the * top-level class itself. */ private ClassSymbol outerCacheClass() { ClassSymbol clazz = outermostClassDef.sym; Scope s = clazz.members(); for (Symbol sym : s.getSymbols(NON_RECURSIVE)) if (sym.kind == TYP && sym.name == names.empty && (sym.flags() & INTERFACE) == 0) return (ClassSymbol) sym; return makeEmptyClass(STATIC | SYNTHETIC, clazz).sym; } /** Return symbol for "class$" method. If there is no method definition * for class$, construct one as follows: * * class class$(String x0) { * try { * return Class.forName(x0); * } catch (ClassNotFoundException x1) { * throw new NoClassDefFoundError(x1.getMessage()); * } * } */ private MethodSymbol classDollarSym(DiagnosticPosition pos) { ClassSymbol outerCacheClass = outerCacheClass(); MethodSymbol classDollarSym = (MethodSymbol)lookupSynthetic(classDollar, outerCacheClass.members()); if (classDollarSym == null) { classDollarSym = new MethodSymbol( STATIC | SYNTHETIC, classDollar, new MethodType( List.of(syms.stringType), types.erasure(syms.classType), List.nil(), syms.methodClass), outerCacheClass); enterSynthetic(pos, classDollarSym, outerCacheClass.members()); JCMethodDecl md = make.MethodDef(classDollarSym, null); try { md.body = classDollarSymBody(pos, md); } catch (CompletionFailure ex) { md.body = make.Block(0, List.nil()); chk.completionError(pos, ex); } JCClassDecl outerCacheClassDef = classDef(outerCacheClass); outerCacheClassDef.defs = outerCacheClassDef.defs.prepend(md); } return classDollarSym; } /** Generate code for class$(String name). */ JCBlock classDollarSymBody(DiagnosticPosition pos, JCMethodDecl md) { MethodSymbol classDollarSym = md.sym; ClassSymbol outerCacheClass = (ClassSymbol)classDollarSym.owner; JCBlock returnResult; // cache the current loader in cl$ // clsym = "private static ClassLoader cl$" VarSymbol clsym = new VarSymbol(STATIC | SYNTHETIC, names.fromString("cl" + target.syntheticNameChar()), syms.classLoaderType, outerCacheClass); enterSynthetic(pos, clsym, outerCacheClass.members()); // emit "private static ClassLoader cl$;" JCVariableDecl cldef = make.VarDef(clsym, null); JCClassDecl outerCacheClassDef = classDef(outerCacheClass); outerCacheClassDef.defs = outerCacheClassDef.defs.prepend(cldef); // newcache := "new cache$1[0]" JCNewArray newcache = make.NewArray(make.Type(outerCacheClass.type), List.of(make.Literal(INT, 0).setType(syms.intType)), null); newcache.type = new ArrayType(types.erasure(outerCacheClass.type), syms.arrayClass); // forNameSym := java.lang.Class.forName( // String s,boolean init,ClassLoader loader) Symbol forNameSym = lookupMethod(make_pos, names.forName, types.erasure(syms.classType), List.of(syms.stringType, syms.booleanType, syms.classLoaderType)); // clvalue := "(cl$ == null) ? // $newcache.getClass().getComponentType().getClassLoader() : cl$" JCExpression clvalue = make.Conditional( makeBinary(EQ, make.Ident(clsym), makeNull()), make.Assign(make.Ident(clsym), makeCall( makeCall(makeCall(newcache, names.getClass, List.nil()), names.getComponentType, List.nil()), names.getClassLoader, List.nil())).setType(syms.classLoaderType), make.Ident(clsym)).setType(syms.classLoaderType); // returnResult := "{ return Class.forName(param1, false, cl$); }" List args = List.of(make.Ident(md.params.head.sym), makeLit(syms.booleanType, 0), clvalue); returnResult = make.Block(0, List.of(make.Call(make.App(make.Ident(forNameSym), args)))); // catchParam := ClassNotFoundException e1 VarSymbol catchParam = new VarSymbol(SYNTHETIC, make.paramName(1), syms.classNotFoundExceptionType, classDollarSym); JCStatement rethrow; // rethrow = "throw new NoClassDefFoundError().initCause(e); JCExpression throwExpr = makeCall(makeNewClass(syms.noClassDefFoundErrorType, List.nil()), names.initCause, List.of(make.Ident(catchParam))); rethrow = make.Throw(throwExpr); // rethrowStmt := "( $rethrow )" JCBlock rethrowStmt = make.Block(0, List.of(rethrow)); // catchBlock := "catch ($catchParam) $rethrowStmt" JCCatch catchBlock = make.Catch(make.VarDef(catchParam, null), rethrowStmt); // tryCatch := "try $returnResult $catchBlock" JCStatement tryCatch = make.Try(returnResult, List.of(catchBlock), null); return make.Block(0, List.of(tryCatch)); } // where /** Create an attributed tree of the form left.name(). */ private JCMethodInvocation makeCall(JCExpression left, Name name, List args) { Assert.checkNonNull(left.type); Symbol funcsym = lookupMethod(make_pos, name, left.type, TreeInfo.types(args)); return make.App(make.Select(left, funcsym), args); } /** The Name Of The variable to cache T.class values. * @param sig The signature of type T. */ private Name cacheName(String sig) { StringBuilder buf = new StringBuilder(); if (sig.startsWith("[")) { buf = buf.append("array"); while (sig.startsWith("[")) { buf = buf.append(target.syntheticNameChar()); sig = sig.substring(1); } if (sig.startsWith("L")) { sig = sig.substring(0, sig.length() - 1); } } else { buf = buf.append("class" + target.syntheticNameChar()); } buf = buf.append(sig.replace('.', target.syntheticNameChar())); return names.fromString(buf.toString()); } /** The variable symbol that caches T.class values. * If none exists yet, create a definition. * @param sig The signature of type T. * @param pos The position to report diagnostics, if any. */ private VarSymbol cacheSym(DiagnosticPosition pos, String sig) { ClassSymbol outerCacheClass = outerCacheClass(); Name cname = cacheName(sig); VarSymbol cacheSym = (VarSymbol)lookupSynthetic(cname, outerCacheClass.members()); if (cacheSym == null) { cacheSym = new VarSymbol( STATIC | SYNTHETIC, cname, types.erasure(syms.classType), outerCacheClass); enterSynthetic(pos, cacheSym, outerCacheClass.members()); JCVariableDecl cacheDef = make.VarDef(cacheSym, null); JCClassDecl outerCacheClassDef = classDef(outerCacheClass); outerCacheClassDef.defs = outerCacheClassDef.defs.prepend(cacheDef); } return cacheSym; } /** The tree simulating a T.class expression. * @param clazz The tree identifying type T. */ private JCExpression classOf(JCTree clazz) { return classOfType(clazz.type, clazz.pos()); } private JCExpression classOfType(Type type, DiagnosticPosition pos) { switch (type.getTag()) { case BYTE: case SHORT: case CHAR: case INT: case LONG: case FLOAT: case DOUBLE: case BOOLEAN: case VOID: // replace with .TYPE ClassSymbol c = types.boxedClass(type); Symbol typeSym = rs.accessBase( rs.findIdentInType(attrEnv, c.type, names.TYPE, KindSelector.VAR), pos, c.type, names.TYPE, true); if (typeSym.kind == VAR) ((VarSymbol)typeSym).getConstValue(); // ensure initializer is evaluated return make.QualIdent(typeSym); case CLASS: case ARRAY: VarSymbol sym = new VarSymbol( STATIC | PUBLIC | FINAL, names._class, syms.classType, type.tsym); return make_at(pos).Select(make.Type(type), sym); default: throw new AssertionError(); } } /************************************************************************** * Code for enabling/disabling assertions. *************************************************************************/ private ClassSymbol assertionsDisabledClassCache; /**Used to create an auxiliary class to hold $assertionsDisabled for interfaces. */ private ClassSymbol assertionsDisabledClass() { if (assertionsDisabledClassCache != null) return assertionsDisabledClassCache; assertionsDisabledClassCache = makeEmptyClass(STATIC | SYNTHETIC, outermostClassDef.sym).sym; return assertionsDisabledClassCache; } // This code is not particularly robust if the user has // previously declared a member named '$assertionsDisabled'. // The same faulty idiom also appears in the translation of // class literals above. We should report an error if a // previous declaration is not synthetic. private JCExpression assertFlagTest(DiagnosticPosition pos) { // Outermost class may be either true class or an interface. ClassSymbol outermostClass = outermostClassDef.sym; //only classes can hold a non-public field, look for a usable one: ClassSymbol container = !currentClass.isInterface() ? currentClass : assertionsDisabledClass(); VarSymbol assertDisabledSym = (VarSymbol)lookupSynthetic(dollarAssertionsDisabled, container.members()); if (assertDisabledSym == null) { assertDisabledSym = new VarSymbol(STATIC | FINAL | SYNTHETIC, dollarAssertionsDisabled, syms.booleanType, container); enterSynthetic(pos, assertDisabledSym, container.members()); Symbol desiredAssertionStatusSym = lookupMethod(pos, names.desiredAssertionStatus, types.erasure(syms.classType), List.nil()); JCClassDecl containerDef = classDef(container); make_at(containerDef.pos()); JCExpression notStatus = makeUnary(NOT, make.App(make.Select( classOfType(types.erasure(outermostClass.type), containerDef.pos()), desiredAssertionStatusSym))); JCVariableDecl assertDisabledDef = make.VarDef(assertDisabledSym, notStatus); containerDef.defs = containerDef.defs.prepend(assertDisabledDef); if (currentClass.isInterface()) { //need to load the assertions enabled/disabled state while //initializing the interface: JCClassDecl currentClassDef = classDef(currentClass); make_at(currentClassDef.pos()); JCStatement dummy = make.If(make.QualIdent(assertDisabledSym), make.Skip(), null); JCBlock clinit = make.Block(STATIC, List.of(dummy)); currentClassDef.defs = currentClassDef.defs.prepend(clinit); } } make_at(pos); return makeUnary(NOT, make.Ident(assertDisabledSym)); } /************************************************************************** * Building blocks for let expressions *************************************************************************/ interface TreeBuilder { JCExpression build(JCExpression arg); } /** Construct an expression using the builder, with the given rval * expression as an argument to the builder. However, the rval * expression must be computed only once, even if used multiple * times in the result of the builder. We do that by * constructing a "let" expression that saves the rvalue into a * temporary variable and then uses the temporary variable in * place of the expression built by the builder. The complete * resulting expression is of the form * 
     *    (let TYPE TEMP = RVAL;
     *     in (BUILDER(TEMP)))
     *
* where TEMP is a newly declared variable * in the let expression. */ JCExpression abstractRval(JCExpression rval, Type type, TreeBuilder builder) { rval = TreeInfo.skipParens(rval); switch (rval.getTag()) { case LITERAL: return builder.build(rval); case IDENT: JCIdent id = (JCIdent) rval; if ((id.sym.flags() & FINAL) != 0 && id.sym.owner.kind == MTH) return builder.build(rval); } Name name = TreeInfo.name(rval); if (name == names._super || name == names._this) return builder.build(rval); VarSymbol var = new VarSymbol(FINAL|SYNTHETIC, names.fromString( target.syntheticNameChar() + "" + rval.hashCode()), type, currentMethodSym); rval = convert(rval,type); JCVariableDecl def = make.VarDef(var, rval); // XXX cast JCExpression built = builder.build(make.Ident(var)); JCExpression res = make.LetExpr(def, built); res.type = built.type; return res; } // same as above, with the type of the temporary variable computed JCExpression abstractRval(JCExpression rval, TreeBuilder builder) { return abstractRval(rval, rval.type, builder); } // same as above, but for an expression that may be used as either // an rvalue or an lvalue. This requires special handling for // Select expressions, where we place the left-hand-side of the // select in a temporary, and for Indexed expressions, where we // place both the indexed expression and the index value in temps. JCExpression abstractLval(JCExpression lval, final TreeBuilder builder) { lval = TreeInfo.skipParens(lval); switch (lval.getTag()) { case IDENT: return builder.build(lval); case SELECT: { final JCFieldAccess s = (JCFieldAccess)lval; Symbol lid = TreeInfo.symbol(s.selected); if (lid != null && lid.kind == TYP) return builder.build(lval); return abstractRval(s.selected, new TreeBuilder() { public JCExpression build(final JCExpression selected) { return builder.build(make.Select(selected, s.sym)); } }); } case INDEXED: { final JCArrayAccess i = (JCArrayAccess)lval; return abstractRval(i.indexed, new TreeBuilder() { public JCExpression build(final JCExpression indexed) { return abstractRval(i.index, syms.intType, new TreeBuilder() { public JCExpression build(final JCExpression index) { JCExpression newLval = make.Indexed(indexed, index); newLval.setType(i.type); return builder.build(newLval); } }); } }); } case TYPECAST: { return abstractLval(((JCTypeCast)lval).expr, builder); } } throw new AssertionError(lval); } // evaluate and discard the first expression, then evaluate the second. JCExpression makeComma(final JCExpression expr1, final JCExpression expr2) { return abstractRval(expr1, new TreeBuilder() { public JCExpression build(final JCExpression discarded) { return expr2; } }); } /************************************************************************** * Translation methods *************************************************************************/ /** Visitor argument: enclosing operator node. */ private JCExpression enclOp; /** Visitor method: Translate a single node. * Attach the source position from the old tree to its replacement tree. */ @Override public T translate(T tree) { if (tree == null) { return null; } else { make_at(tree.pos()); T result = super.translate(tree); if (endPosTable != null && result != tree) { endPosTable.replaceTree(tree, result); } return result; } } /** Visitor method: Translate a single node, boxing or unboxing if needed. */ public T translate(T tree, Type type) { return (tree == null) ? null : boxIfNeeded(translate(tree), type); } /** Visitor method: Translate tree. */ public T translate(T tree, JCExpression enclOp) { JCExpression prevEnclOp = this.enclOp; this.enclOp = enclOp; T res = translate(tree); this.enclOp = prevEnclOp; return res; } /** Visitor method: Translate list of trees. */ public List translate(List trees, JCExpression enclOp) { JCExpression prevEnclOp = this.enclOp; this.enclOp = enclOp; List res = translate(trees); this.enclOp = prevEnclOp; return res; } /** Visitor method: Translate list of trees. */ public List translate(List trees, Type type) { if (trees == null) return null; for (List l = trees; l.nonEmpty(); l = l.tail) l.head = translate(l.head, type); return trees; } public void visitPackageDef(JCPackageDecl tree) { if (!needPackageInfoClass(tree)) return; long flags = Flags.ABSTRACT | Flags.INTERFACE; // package-info is marked SYNTHETIC in JDK 1.6 and later releases flags = flags | Flags.SYNTHETIC; ClassSymbol c = tree.packge.package_info; c.setAttributes(tree.packge); c.flags_field |= flags; ClassType ctype = (ClassType) c.type; ctype.supertype_field = syms.objectType; ctype.interfaces_field = List.nil(); createInfoClass(tree.annotations, c); } // where private boolean needPackageInfoClass(JCPackageDecl pd) { switch (pkginfoOpt) { case ALWAYS: return true; case LEGACY: return pd.getAnnotations().nonEmpty(); case NONEMPTY: for (Attribute.Compound a : pd.packge.getDeclarationAttributes()) { Attribute.RetentionPolicy p = types.getRetention(a); if (p != Attribute.RetentionPolicy.SOURCE) return true; } return false; } throw new AssertionError(); } public void visitModuleDef(JCModuleDecl tree) { ModuleSymbol msym = tree.sym; ClassSymbol c = msym.module_info; c.flags_field |= Flags.MODULE; createInfoClass(List.nil(), tree.sym.module_info); } private void createInfoClass(List annots, ClassSymbol c) { long flags = Flags.ABSTRACT | Flags.INTERFACE; JCClassDecl infoClass = make.ClassDef(make.Modifiers(flags, annots), c.name, List.nil(), null, List.nil(), List.nil()); infoClass.sym = c; translated.append(infoClass); } public void visitClassDef(JCClassDecl tree) { Env prevEnv = attrEnv; ClassSymbol currentClassPrev = currentClass; MethodSymbol currentMethodSymPrev = currentMethodSym; currentClass = tree.sym; currentMethodSym = null; attrEnv = typeEnvs.remove(currentClass); if (attrEnv == null) attrEnv = prevEnv; classdefs.put(currentClass, tree); proxies = proxies.dup(currentClass); List prevOuterThisStack = outerThisStack; // If this is an enum definition if ((tree.mods.flags & ENUM) != 0 && (types.supertype(currentClass.type).tsym.flags() & ENUM) == 0) visitEnumDef(tree); // If this is a nested class, define a this$n field for // it and add to proxies. JCVariableDecl otdef = null; if (currentClass.hasOuterInstance()) otdef = outerThisDef(tree.pos, currentClass); // If this is a local class, define proxies for all its free variables. List fvdefs = freevarDefs( tree.pos, freevars(currentClass), currentClass); // Recursively translate superclass, interfaces. tree.extending = translate(tree.extending); tree.implementing = translate(tree.implementing); if (currentClass.isLocal()) { ClassSymbol encl = currentClass.owner.enclClass(); if (encl.trans_local == null) { encl.trans_local = List.nil(); } encl.trans_local = encl.trans_local.prepend(currentClass); } // Recursively translate members, taking into account that new members // might be created during the translation and prepended to the member // list `tree.defs'. List seen = List.nil(); while (tree.defs != seen) { List unseen = tree.defs; for (List l = unseen; l.nonEmpty() && l != seen; l = l.tail) { JCTree outermostMemberDefPrev = outermostMemberDef; if (outermostMemberDefPrev == null) outermostMemberDef = l.head; l.head = translate(l.head); outermostMemberDef = outermostMemberDefPrev; } seen = unseen; } // Convert a protected modifier to public, mask static modifier. if ((tree.mods.flags & PROTECTED) != 0) tree.mods.flags |= PUBLIC; tree.mods.flags &= ClassFlags; // Convert name to flat representation, replacing '.' by '$'. tree.name = Convert.shortName(currentClass.flatName()); // Add this$n and free variables proxy definitions to class. for (List l = fvdefs; l.nonEmpty(); l = l.tail) { tree.defs = tree.defs.prepend(l.head); enterSynthetic(tree.pos(), l.head.sym, currentClass.members()); } if (currentClass.hasOuterInstance()) { tree.defs = tree.defs.prepend(otdef); enterSynthetic(tree.pos(), otdef.sym, currentClass.members()); } proxies = proxies.leave(); outerThisStack = prevOuterThisStack; // Append translated tree to `translated' queue. translated.append(tree); attrEnv = prevEnv; currentClass = currentClassPrev; currentMethodSym = currentMethodSymPrev; // Return empty block {} as a placeholder for an inner class. result = make_at(tree.pos()).Block(SYNTHETIC, List.nil()); } /** Translate an enum class. */ private void visitEnumDef(JCClassDecl tree) { make_at(tree.pos()); // add the supertype, if needed if (tree.extending == null) tree.extending = make.Type(types.supertype(tree.type)); // classOfType adds a cache field to tree.defs JCExpression e_class = classOfType(tree.sym.type, tree.pos()). setType(types.erasure(syms.classType)); // process each enumeration constant, adding implicit constructor parameters int nextOrdinal = 0; ListBuffer values = new ListBuffer<>(); ListBuffer enumDefs = new ListBuffer<>(); ListBuffer otherDefs = new ListBuffer<>(); for (List defs = tree.defs; defs.nonEmpty(); defs=defs.tail) { if (defs.head.hasTag(VARDEF) && (((JCVariableDecl) defs.head).mods.flags & ENUM) != 0) { JCVariableDecl var = (JCVariableDecl)defs.head; visitEnumConstantDef(var, nextOrdinal++); values.append(make.QualIdent(var.sym)); enumDefs.append(var); } else { otherDefs.append(defs.head); } } // private static final T[] #VALUES = { a, b, c }; Name valuesName = names.fromString(target.syntheticNameChar() + "VALUES"); while (tree.sym.members().findFirst(valuesName) != null) // avoid name clash valuesName = names.fromString(valuesName + "" + target.syntheticNameChar()); Type arrayType = new ArrayType(types.erasure(tree.type), syms.arrayClass); VarSymbol valuesVar = new VarSymbol(PRIVATE|FINAL|STATIC|SYNTHETIC, valuesName, arrayType, tree.type.tsym); JCNewArray newArray = make.NewArray(make.Type(types.erasure(tree.type)), List.nil(), values.toList()); newArray.type = arrayType; enumDefs.append(make.VarDef(valuesVar, newArray)); tree.sym.members().enter(valuesVar); Symbol valuesSym = lookupMethod(tree.pos(), names.values, tree.type, List.nil()); List valuesBody; if (useClone()) { // return (T[]) $VALUES.clone(); JCTypeCast valuesResult = make.TypeCast(valuesSym.type.getReturnType(), make.App(make.Select(make.Ident(valuesVar), syms.arrayCloneMethod))); valuesBody = List.of(make.Return(valuesResult)); } else { // template: T[] $result = new T[$values.length]; Name resultName = names.fromString(target.syntheticNameChar() + "result"); while (tree.sym.members().findFirst(resultName) != null) // avoid name clash resultName = names.fromString(resultName + "" + target.syntheticNameChar()); VarSymbol resultVar = new VarSymbol(FINAL|SYNTHETIC, resultName, arrayType, valuesSym); JCNewArray resultArray = make.NewArray(make.Type(types.erasure(tree.type)), List.of(make.Select(make.Ident(valuesVar), syms.lengthVar)), null); resultArray.type = arrayType; JCVariableDecl decl = make.VarDef(resultVar, resultArray); // template: System.arraycopy($VALUES, 0, $result, 0, $VALUES.length); if (systemArraycopyMethod == null) { systemArraycopyMethod = new MethodSymbol(PUBLIC | STATIC, names.fromString("arraycopy"), new MethodType(List.of(syms.objectType, syms.intType, syms.objectType, syms.intType, syms.intType), syms.voidType, List.nil(), syms.methodClass), syms.systemType.tsym); } JCStatement copy = make.Exec(make.App(make.Select(make.Ident(syms.systemType.tsym), systemArraycopyMethod), List.of(make.Ident(valuesVar), make.Literal(0), make.Ident(resultVar), make.Literal(0), make.Select(make.Ident(valuesVar), syms.lengthVar)))); // template: return $result; JCStatement ret = make.Return(make.Ident(resultVar)); valuesBody = List.of(decl, copy, ret); } JCMethodDecl valuesDef = make.MethodDef((MethodSymbol)valuesSym, make.Block(0, valuesBody)); enumDefs.append(valuesDef); if (debugLower) System.err.println(tree.sym + ".valuesDef = " + valuesDef); /** The template for the following code is: * * public static E valueOf(String name) { * return (E)Enum.valueOf(E.class, name); * } * * where E is tree.sym */ MethodSymbol valueOfSym = lookupMethod(tree.pos(), names.valueOf, tree.sym.type, List.of(syms.stringType)); Assert.check((valueOfSym.flags() & STATIC) != 0); VarSymbol nameArgSym = valueOfSym.params.head; JCIdent nameVal = make.Ident(nameArgSym); JCStatement enum_ValueOf = make.Return(make.TypeCast(tree.sym.type, makeCall(make.Ident(syms.enumSym), names.valueOf, List.of(e_class, nameVal)))); JCMethodDecl valueOf = make.MethodDef(valueOfSym, make.Block(0, List.of(enum_ValueOf))); nameVal.sym = valueOf.params.head.sym; if (debugLower) System.err.println(tree.sym + ".valueOf = " + valueOf); enumDefs.append(valueOf); enumDefs.appendList(otherDefs.toList()); tree.defs = enumDefs.toList(); } // where private MethodSymbol systemArraycopyMethod; private boolean useClone() { try { return syms.objectType.tsym.members().findFirst(names.clone) != null; } catch (CompletionFailure e) { return false; } } /** Translate an enumeration constant and its initializer. */ private void visitEnumConstantDef(JCVariableDecl var, int ordinal) { JCNewClass varDef = (JCNewClass)var.init; varDef.args = varDef.args. prepend(makeLit(syms.intType, ordinal)). prepend(makeLit(syms.stringType, var.name.toString())); } public void visitMethodDef(JCMethodDecl tree) { if (tree.name == names.init && (currentClass.flags_field&ENUM) != 0) { // Add "String $enum$name, int $enum$ordinal" to the beginning of the // argument list for each constructor of an enum. JCVariableDecl nameParam = make_at(tree.pos()). Param(names.fromString(target.syntheticNameChar() + "enum" + target.syntheticNameChar() + "name"), syms.stringType, tree.sym); nameParam.mods.flags |= SYNTHETIC; nameParam.sym.flags_field |= SYNTHETIC; JCVariableDecl ordParam = make. Param(names.fromString(target.syntheticNameChar() + "enum" + target.syntheticNameChar() + "ordinal"), syms.intType, tree.sym); ordParam.mods.flags |= SYNTHETIC; ordParam.sym.flags_field |= SYNTHETIC; MethodSymbol m = tree.sym; tree.params = tree.params.prepend(ordParam).prepend(nameParam); m.extraParams = m.extraParams.prepend(ordParam.sym); m.extraParams = m.extraParams.prepend(nameParam.sym); Type olderasure = m.erasure(types); m.erasure_field = new MethodType( olderasure.getParameterTypes().prepend(syms.intType).prepend(syms.stringType), olderasure.getReturnType(), olderasure.getThrownTypes(), syms.methodClass); } JCMethodDecl prevMethodDef = currentMethodDef; MethodSymbol prevMethodSym = currentMethodSym; try { currentMethodDef = tree; currentMethodSym = tree.sym; visitMethodDefInternal(tree); } finally { currentMethodDef = prevMethodDef; currentMethodSym = prevMethodSym; } } private void visitMethodDefInternal(JCMethodDecl tree) { if (tree.name == names.init && (currentClass.isInner() || currentClass.isLocal())) { // We are seeing a constructor of an inner class. MethodSymbol m = tree.sym; // Push a new proxy scope for constructor parameters. // and create definitions for any this$n and proxy parameters. proxies = proxies.dup(m); List prevOuterThisStack = outerThisStack; List fvs = freevars(currentClass); JCVariableDecl otdef = null; if (currentClass.hasOuterInstance()) otdef = outerThisDef(tree.pos, m); List fvdefs = freevarDefs(tree.pos, fvs, m, PARAMETER); // Recursively translate result type, parameters and thrown list. tree.restype = translate(tree.restype); tree.params = translateVarDefs(tree.params); tree.thrown = translate(tree.thrown); // when compiling stubs, don't process body if (tree.body == null) { result = tree; return; } // Add this$n (if needed) in front of and free variables behind // constructor parameter list. tree.params = tree.params.appendList(fvdefs); if (currentClass.hasOuterInstance()) { tree.params = tree.params.prepend(otdef); } // If this is an initial constructor, i.e., it does not start with // this(...), insert initializers for this$n and proxies // before (pre-1.4, after) the call to superclass constructor. JCStatement selfCall = translate(tree.body.stats.head); List added = List.nil(); if (fvs.nonEmpty()) { List addedargtypes = List.nil(); for (List l = fvs; l.nonEmpty(); l = l.tail) { final Name pName = proxyName(l.head.name); m.capturedLocals = m.capturedLocals.prepend((VarSymbol) (proxies.findFirst(pName))); if (TreeInfo.isInitialConstructor(tree)) { added = added.prepend( initField(tree.body.pos, pName)); } addedargtypes = addedargtypes.prepend(l.head.erasure(types)); } Type olderasure = m.erasure(types); m.erasure_field = new MethodType( olderasure.getParameterTypes().appendList(addedargtypes), olderasure.getReturnType(), olderasure.getThrownTypes(), syms.methodClass); } if (currentClass.hasOuterInstance() && TreeInfo.isInitialConstructor(tree)) { added = added.prepend(initOuterThis(tree.body.pos)); } // pop local variables from proxy stack proxies = proxies.leave(); // recursively translate following local statements and // combine with this- or super-call List stats = translate(tree.body.stats.tail); tree.body.stats = stats.prepend(selfCall).prependList(added); outerThisStack = prevOuterThisStack; } else { Map prevLambdaTranslationMap = lambdaTranslationMap; try { lambdaTranslationMap = (tree.sym.flags() & SYNTHETIC) != 0 && tree.sym.name.startsWith(names.lambda) ? makeTranslationMap(tree) : null; super.visitMethodDef(tree); } finally { lambdaTranslationMap = prevLambdaTranslationMap; } } result = tree; } //where private Map makeTranslationMap(JCMethodDecl tree) { Map translationMap = new HashMap<>(); for (JCVariableDecl vd : tree.params) { Symbol p = vd.sym; if (p != p.baseSymbol()) { translationMap.put(p.baseSymbol(), p); } } return translationMap; } public void visitTypeCast(JCTypeCast tree) { tree.clazz = translate(tree.clazz); if (tree.type.isPrimitive() != tree.expr.type.isPrimitive()) tree.expr = translate(tree.expr, tree.type); else tree.expr = translate(tree.expr); result = tree; } public void visitNewClass(JCNewClass tree) { ClassSymbol c = (ClassSymbol)tree.constructor.owner; // Box arguments, if necessary boolean isEnum = (tree.constructor.owner.flags() & ENUM) != 0; List argTypes = tree.constructor.type.getParameterTypes(); if (isEnum) argTypes = argTypes.prepend(syms.intType).prepend(syms.stringType); tree.args = boxArgs(argTypes, tree.args, tree.varargsElement); tree.varargsElement = null; // If created class is local, add free variables after // explicit constructor arguments. if (c.isLocal()) { tree.args = tree.args.appendList(loadFreevars(tree.pos(), freevars(c))); } // If an access constructor is used, append null as a last argument. Symbol constructor = accessConstructor(tree.pos(), tree.constructor); if (constructor != tree.constructor) { tree.args = tree.args.append(makeNull()); tree.constructor = constructor; } // If created class has an outer instance, and new is qualified, pass // qualifier as first argument. If new is not qualified, pass the // correct outer instance as first argument. if (c.hasOuterInstance()) { JCExpression thisArg; if (tree.encl != null) { thisArg = attr.makeNullCheck(translate(tree.encl)); thisArg.type = tree.encl.type; } else if (c.isLocal()) { // local class thisArg = makeThis(tree.pos(), c.type.getEnclosingType().tsym); } else { // nested class thisArg = makeOwnerThis(tree.pos(), c, false); } tree.args = tree.args.prepend(thisArg); } tree.encl = null; // If we have an anonymous class, create its flat version, rather // than the class or interface following new. if (tree.def != null) { translate(tree.def); tree.clazz = access(make_at(tree.clazz.pos()).Ident(tree.def.sym)); tree.def = null; } else { tree.clazz = access(c, tree.clazz, enclOp, false); } result = tree; } // Simplify conditionals with known constant controlling expressions. // This allows us to avoid generating supporting declarations for // the dead code, which will not be eliminated during code generation. // Note that Flow.isFalse and Flow.isTrue only return true // for constant expressions in the sense of JLS 15.27, which // are guaranteed to have no side-effects. More aggressive // constant propagation would require that we take care to // preserve possible side-effects in the condition expression. // One common case is equality expressions involving a constant and null. // Since null is not a constant expression (because null cannot be // represented in the constant pool), equality checks involving null are // not captured by Flow.isTrue/isFalse. // Equality checks involving a constant and null, e.g. // "" == null // are safe to simplify as no side-effects can occur. private boolean isTrue(JCTree exp) { if (exp.type.isTrue()) return true; Boolean b = expValue(exp); return b == null ? false : b; } private boolean isFalse(JCTree exp) { if (exp.type.isFalse()) return true; Boolean b = expValue(exp); return b == null ? false : !b; } /* look for (in)equality relations involving null. * return true - if expression is always true * false - if expression is always false * null - if expression cannot be eliminated */ private Boolean expValue(JCTree exp) { while (exp.hasTag(PARENS)) exp = ((JCParens)exp).expr; boolean eq; switch (exp.getTag()) { case EQ: eq = true; break; case NE: eq = false; break; default: return null; } // we have a JCBinary(EQ|NE) // check if we have two literals (constants or null) JCBinary b = (JCBinary)exp; if (b.lhs.type.hasTag(BOT)) return expValueIsNull(eq, b.rhs); if (b.rhs.type.hasTag(BOT)) return expValueIsNull(eq, b.lhs); return null; } private Boolean expValueIsNull(boolean eq, JCTree t) { if (t.type.hasTag(BOT)) return Boolean.valueOf(eq); if (t.hasTag(LITERAL)) return Boolean.valueOf(!eq); return null; } /** Visitor method for conditional expressions. */ @Override public void visitConditional(JCConditional tree) { JCTree cond = tree.cond = translate(tree.cond, syms.booleanType); if (isTrue(cond)) { result = convert(translate(tree.truepart, tree.type), tree.type); addPrunedInfo(cond); } else if (isFalse(cond)) { result = convert(translate(tree.falsepart, tree.type), tree.type); addPrunedInfo(cond); } else { // Condition is not a compile-time constant. tree.truepart = translate(tree.truepart, tree.type); tree.falsepart = translate(tree.falsepart, tree.type); result = tree; } } //where private JCExpression convert(JCExpression tree, Type pt) { if (tree.type == pt || tree.type.hasTag(BOT)) return tree; JCExpression result = make_at(tree.pos()).TypeCast(make.Type(pt), tree); result.type = (tree.type.constValue() != null) ? cfolder.coerce(tree.type, pt) : pt; return result; } /** Visitor method for if statements. */ public void visitIf(JCIf tree) { JCTree cond = tree.cond = translate(tree.cond, syms.booleanType); if (isTrue(cond)) { result = translate(tree.thenpart); addPrunedInfo(cond); } else if (isFalse(cond)) { if (tree.elsepart != null) { result = translate(tree.elsepart); } else { result = make.Skip(); } addPrunedInfo(cond); } else { // Condition is not a compile-time constant. tree.thenpart = translate(tree.thenpart); tree.elsepart = translate(tree.elsepart); result = tree; } } /** Visitor method for assert statements. Translate them away. */ public void visitAssert(JCAssert tree) { DiagnosticPosition detailPos = (tree.detail == null) ? tree.pos() : tree.detail.pos(); tree.cond = translate(tree.cond, syms.booleanType); if (!tree.cond.type.isTrue()) { JCExpression cond = assertFlagTest(tree.pos()); List exnArgs = (tree.detail == null) ? List.nil() : List.of(translate(tree.detail)); if (!tree.cond.type.isFalse()) { cond = makeBinary (AND, cond, makeUnary(NOT, tree.cond)); } result = make.If(cond, make_at(tree). Throw(makeNewClass(syms.assertionErrorType, exnArgs)), null); } else { result = make.Skip(); } } public void visitApply(JCMethodInvocation tree) { Symbol meth = TreeInfo.symbol(tree.meth); List argtypes = meth.type.getParameterTypes(); if (meth.name == names.init && meth.owner == syms.enumSym) argtypes = argtypes.tail.tail; tree.args = boxArgs(argtypes, tree.args, tree.varargsElement); tree.varargsElement = null; Name methName = TreeInfo.name(tree.meth); if (meth.name==names.init) { // We are seeing a this(...) or super(...) constructor call. // If an access constructor is used, append null as a last argument. Symbol constructor = accessConstructor(tree.pos(), meth); if (constructor != meth) { tree.args = tree.args.append(makeNull()); TreeInfo.setSymbol(tree.meth, constructor); } // If we are calling a constructor of a local class, add // free variables after explicit constructor arguments. ClassSymbol c = (ClassSymbol)constructor.owner; if (c.isLocal()) { tree.args = tree.args.appendList(loadFreevars(tree.pos(), freevars(c))); } // If we are calling a constructor of an enum class, pass // along the name and ordinal arguments if ((c.flags_field&ENUM) != 0 || c.getQualifiedName() == names.java_lang_Enum) { List params = currentMethodDef.params; if (currentMethodSym.owner.hasOuterInstance()) params = params.tail; // drop this$n tree.args = tree.args .prepend(make_at(tree.pos()).Ident(params.tail.head.sym)) // ordinal .prepend(make.Ident(params.head.sym)); // name } // If we are calling a constructor of a class with an outer // instance, and the call // is qualified, pass qualifier as first argument in front of // the explicit constructor arguments. If the call // is not qualified, pass the correct outer instance as // first argument. if (c.hasOuterInstance()) { JCExpression thisArg; if (tree.meth.hasTag(SELECT)) { thisArg = attr. makeNullCheck(translate(((JCFieldAccess) tree.meth).selected)); tree.meth = make.Ident(constructor); ((JCIdent) tree.meth).name = methName; } else if (c.isLocal() || methName == names._this){ // local class or this() call thisArg = makeThis(tree.meth.pos(), c.type.getEnclosingType().tsym); } else { // super() call of nested class - never pick 'this' thisArg = makeOwnerThisN(tree.meth.pos(), c, false); } tree.args = tree.args.prepend(thisArg); } } else { // We are seeing a normal method invocation; translate this as usual. tree.meth = translate(tree.meth); // If the translated method itself is an Apply tree, we are // seeing an access method invocation. In this case, append // the method arguments to the arguments of the access method. if (tree.meth.hasTag(APPLY)) { JCMethodInvocation app = (JCMethodInvocation)tree.meth; app.args = tree.args.prependList(app.args); result = app; return; } } result = tree; } List boxArgs(List parameters, List _args, Type varargsElement) { List args = _args; if (parameters.isEmpty()) return args; boolean anyChanges = false; ListBuffer result = new ListBuffer<>(); while (parameters.tail.nonEmpty()) { JCExpression arg = translate(args.head, parameters.head); anyChanges |= (arg != args.head); result.append(arg); args = args.tail; parameters = parameters.tail; } Type parameter = parameters.head; if (varargsElement != null) { anyChanges = true; ListBuffer elems = new ListBuffer<>(); while (args.nonEmpty()) { JCExpression arg = translate(args.head, varargsElement); elems.append(arg); args = args.tail; } JCNewArray boxedArgs = make.NewArray(make.Type(varargsElement), List.nil(), elems.toList()); boxedArgs.type = new ArrayType(varargsElement, syms.arrayClass); result.append(boxedArgs); } else { if (args.length() != 1) throw new AssertionError(args); JCExpression arg = translate(args.head, parameter); anyChanges |= (arg != args.head); result.append(arg); if (!anyChanges) return _args; } return result.toList(); } /** Expand a boxing or unboxing conversion if needed. */ @SuppressWarnings("unchecked") // XXX unchecked T boxIfNeeded(T tree, Type type) { boolean havePrimitive = tree.type.isPrimitive(); if (havePrimitive == type.isPrimitive()) return tree; if (havePrimitive) { Type unboxedTarget = types.unboxedType(type); if (!unboxedTarget.hasTag(NONE)) { if (!types.isSubtype(tree.type, unboxedTarget)) //e.g. Character c = 89; tree.type = unboxedTarget.constType(tree.type.constValue()); return (T)boxPrimitive(tree, types.erasure(type)); } else { tree = (T)boxPrimitive(tree); } } else { tree = (T)unbox(tree, type); } return tree; } /** Box up a single primitive expression. */ JCExpression boxPrimitive(JCExpression tree) { return boxPrimitive(tree, types.boxedClass(tree.type).type); } /** Box up a single primitive expression. */ JCExpression boxPrimitive(JCExpression tree, Type box) { make_at(tree.pos()); Symbol valueOfSym = lookupMethod(tree.pos(), names.valueOf, box, List.nil() .prepend(tree.type)); return make.App(make.QualIdent(valueOfSym), List.of(tree)); } /** Unbox an object to a primitive value. */ JCExpression unbox(JCExpression tree, Type primitive) { Type unboxedType = types.unboxedType(tree.type); if (unboxedType.hasTag(NONE)) { unboxedType = primitive; if (!unboxedType.isPrimitive()) throw new AssertionError(unboxedType); make_at(tree.pos()); tree = make.TypeCast(types.boxedClass(unboxedType).type, tree); } else { // There must be a conversion from unboxedType to primitive. if (!types.isSubtype(unboxedType, primitive)) throw new AssertionError(tree); } make_at(tree.pos()); Symbol valueSym = lookupMethod(tree.pos(), unboxedType.tsym.name.append(names.Value), // x.intValue() tree.type, List.nil()); return make.App(make.Select(tree, valueSym)); } /** Visitor method for parenthesized expressions. * If the subexpression has changed, omit the parens. */ public void visitParens(JCParens tree) { JCTree expr = translate(tree.expr); result = ((expr == tree.expr) ? tree : expr); } public void visitIndexed(JCArrayAccess tree) { tree.indexed = translate(tree.indexed); tree.index = translate(tree.index, syms.intType); result = tree; } public void visitAssign(JCAssign tree) { tree.lhs = translate(tree.lhs, tree); tree.rhs = translate(tree.rhs, tree.lhs.type); // If translated left hand side is an Apply, we are // seeing an access method invocation. In this case, append // right hand side as last argument of the access method. if (tree.lhs.hasTag(APPLY)) { JCMethodInvocation app = (JCMethodInvocation)tree.lhs; app.args = List.of(tree.rhs).prependList(app.args); result = app; } else { result = tree; } } public void visitAssignop(final JCAssignOp tree) { final boolean boxingReq = !tree.lhs.type.isPrimitive() && tree.operator.type.getReturnType().isPrimitive(); AssignopDependencyScanner depScanner = new AssignopDependencyScanner(tree); depScanner.scan(tree.rhs); if (boxingReq || depScanner.dependencyFound) { // boxing required; need to rewrite as x = (unbox typeof x)(x op y); // or if x == (typeof x)z then z = (unbox typeof x)((typeof x)z op y) // (but without recomputing x) JCTree newTree = abstractLval(tree.lhs, new TreeBuilder() { public JCExpression build(final JCExpression lhs) { JCTree.Tag newTag = tree.getTag().noAssignOp(); // Erasure (TransTypes) can change the type of // tree.lhs. However, we can still get the // unerased type of tree.lhs as it is stored // in tree.type in Attr. OperatorSymbol newOperator = operators.resolveBinary(tree, newTag, tree.type, tree.rhs.type); JCExpression expr = (JCExpression) lhs.clone(); if (expr.type != tree.type) expr = make.TypeCast(tree.type, expr); JCBinary opResult = make.Binary(newTag, expr, tree.rhs); opResult.operator = newOperator; opResult.type = newOperator.type.getReturnType(); JCExpression newRhs = boxingReq ? make.TypeCast(types.unboxedType(tree.type), opResult) : opResult; return make.Assign(lhs, newRhs).setType(tree.type); } }); result = translate(newTree); return; } tree.lhs = translate(tree.lhs, tree); tree.rhs = translate(tree.rhs, tree.operator.type.getParameterTypes().tail.head); // If translated left hand side is an Apply, we are // seeing an access method invocation. In this case, append // right hand side as last argument of the access method. if (tree.lhs.hasTag(APPLY)) { JCMethodInvocation app = (JCMethodInvocation)tree.lhs; // if operation is a += on strings, // make sure to convert argument to string JCExpression rhs = tree.operator.opcode == string_add ? makeString(tree.rhs) : tree.rhs; app.args = List.of(rhs).prependList(app.args); result = app; } else { result = tree; } } class AssignopDependencyScanner extends TreeScanner { Symbol sym; boolean dependencyFound = false; AssignopDependencyScanner(JCAssignOp tree) { this.sym = TreeInfo.symbol(tree.lhs); } @Override public void scan(JCTree tree) { if (tree != null && sym != null) { tree.accept(this); } } @Override public void visitAssignop(JCAssignOp tree) { if (TreeInfo.symbol(tree.lhs) == sym) { dependencyFound = true; return; } super.visitAssignop(tree); } @Override public void visitUnary(JCUnary tree) { if (TreeInfo.symbol(tree.arg) == sym) { dependencyFound = true; return; } super.visitUnary(tree); } } /** Lower a tree of the form e++ or e-- where e is an object type */ JCExpression lowerBoxedPostop(final JCUnary tree) { // translate to tmp1=lval(e); tmp2=tmp1; tmp1 OP 1; tmp2 // or // translate to tmp1=lval(e); tmp2=tmp1; (typeof tree)tmp1 OP 1; tmp2 // where OP is += or -= final boolean cast = TreeInfo.skipParens(tree.arg).hasTag(TYPECAST); return abstractLval(tree.arg, new TreeBuilder() { public JCExpression build(final JCExpression tmp1) { return abstractRval(tmp1, tree.arg.type, new TreeBuilder() { public JCExpression build(final JCExpression tmp2) { JCTree.Tag opcode = (tree.hasTag(POSTINC)) ? PLUS_ASG : MINUS_ASG; JCExpression lhs = (JCExpression)tmp1.clone(); lhs = cast ? make.TypeCast(tree.arg.type, lhs) : lhs; JCExpression update = makeAssignop(opcode, lhs, make.Literal(1)); return makeComma(update, tmp2); } }); } }); } public void visitUnary(JCUnary tree) { boolean isUpdateOperator = tree.getTag().isIncOrDecUnaryOp(); if (isUpdateOperator && !tree.arg.type.isPrimitive()) { switch(tree.getTag()) { case PREINC: // ++ e // translate to e += 1 case PREDEC: // -- e // translate to e -= 1 { JCTree.Tag opcode = (tree.hasTag(PREINC)) ? PLUS_ASG : MINUS_ASG; JCAssignOp newTree = makeAssignop(opcode, tree.arg, make.Literal(1)); result = translate(newTree, tree.type); return; } case POSTINC: // e ++ case POSTDEC: // e -- { result = translate(lowerBoxedPostop(tree), tree.type); return; } } throw new AssertionError(tree); } tree.arg = boxIfNeeded(translate(tree.arg, tree), tree.type); if (tree.hasTag(NOT) && tree.arg.type.constValue() != null) { tree.type = cfolder.fold1(bool_not, tree.arg.type); } // If translated left hand side is an Apply, we are // seeing an access method invocation. In this case, return // that access method invocation as result. if (isUpdateOperator && tree.arg.hasTag(APPLY)) { result = tree.arg; } else { result = tree; } } public void visitBinary(JCBinary tree) { List formals = tree.operator.type.getParameterTypes(); JCTree lhs = tree.lhs = translate(tree.lhs, formals.head); switch (tree.getTag()) { case OR: if (isTrue(lhs)) { result = lhs; return; } if (isFalse(lhs)) { result = translate(tree.rhs, formals.tail.head); return; } break; case AND: if (isFalse(lhs)) { result = lhs; return; } if (isTrue(lhs)) { result = translate(tree.rhs, formals.tail.head); return; } break; } tree.rhs = translate(tree.rhs, formals.tail.head); result = tree; } public void visitIdent(JCIdent tree) { result = access(tree.sym, tree, enclOp, false); } /** Translate away the foreach loop. */ public void visitForeachLoop(JCEnhancedForLoop tree) { if (types.elemtype(tree.expr.type) == null) visitIterableForeachLoop(tree); else visitArrayForeachLoop(tree); } // where /** * A statement of the form * * 
         *     for ( T v : arrayexpr ) stmt;
         *
* * (where arrayexpr is of an array type) gets translated to * * 
{@code
         *     for ( { arraytype #arr = arrayexpr;
         *             int #len = array.length;
         *             int #i = 0; };
         *           #i < #len; i$++ ) {
         *         T v = arr$[#i];
         *         stmt;
         *     }
         * }
* * where #arr, #len, and #i are freshly named synthetic local variables. */ private void visitArrayForeachLoop(JCEnhancedForLoop tree) { make_at(tree.expr.pos()); VarSymbol arraycache = new VarSymbol(SYNTHETIC, names.fromString("arr" + target.syntheticNameChar()), tree.expr.type, currentMethodSym); JCStatement arraycachedef = make.VarDef(arraycache, tree.expr); VarSymbol lencache = new VarSymbol(SYNTHETIC, names.fromString("len" + target.syntheticNameChar()), syms.intType, currentMethodSym); JCStatement lencachedef = make. VarDef(lencache, make.Select(make.Ident(arraycache), syms.lengthVar)); VarSymbol index = new VarSymbol(SYNTHETIC, names.fromString("i" + target.syntheticNameChar()), syms.intType, currentMethodSym); JCVariableDecl indexdef = make.VarDef(index, make.Literal(INT, 0)); indexdef.init.type = indexdef.type = syms.intType.constType(0); List loopinit = List.of(arraycachedef, lencachedef, indexdef); JCBinary cond = makeBinary(LT, make.Ident(index), make.Ident(lencache)); JCExpressionStatement step = make.Exec(makeUnary(PREINC, make.Ident(index))); Type elemtype = types.elemtype(tree.expr.type); JCExpression loopvarinit = make.Indexed(make.Ident(arraycache), make.Ident(index)).setType(elemtype); JCVariableDecl loopvardef = (JCVariableDecl)make.VarDef(tree.var.mods, tree.var.name, tree.var.vartype, loopvarinit).setType(tree.var.type); loopvardef.sym = tree.var.sym; JCBlock body = make. Block(0, List.of(loopvardef, tree.body)); result = translate(make. ForLoop(loopinit, cond, List.of(step), body)); patchTargets(body, tree, result); } /** Patch up break and continue targets. */ private void patchTargets(JCTree body, final JCTree src, final JCTree dest) { class Patcher extends TreeScanner { public void visitBreak(JCBreak tree) { if (tree.target == src) tree.target = dest; } public void visitContinue(JCContinue tree) { if (tree.target == src) tree.target = dest; } public void visitClassDef(JCClassDecl tree) {} } new Patcher().scan(body); } /** * A statement of the form * * 
         *     for ( T v : coll ) stmt ;
         *
* * (where coll implements {@code Iterable}) gets translated to * * 
{@code
         *     for ( Iterator #i = coll.iterator(); #i.hasNext(); ) {
         *         T v = (T) #i.next();
         *         stmt;
         *     }
         * }
* * where #i is a freshly named synthetic local variable. */ private void visitIterableForeachLoop(JCEnhancedForLoop tree) { make_at(tree.expr.pos()); Type iteratorTarget = syms.objectType; Type iterableType = types.asSuper(types.cvarUpperBound(tree.expr.type), syms.iterableType.tsym); if (iterableType.getTypeArguments().nonEmpty()) iteratorTarget = types.erasure(iterableType.getTypeArguments().head); Type eType = types.skipTypeVars(tree.expr.type, false); tree.expr.type = types.erasure(eType); if (eType.isCompound()) tree.expr = make.TypeCast(types.erasure(iterableType), tree.expr); Symbol iterator = lookupMethod(tree.expr.pos(), names.iterator, eType, List.nil()); VarSymbol itvar = new VarSymbol(SYNTHETIC, names.fromString("i" + target.syntheticNameChar()), types.erasure(types.asSuper(iterator.type.getReturnType(), syms.iteratorType.tsym)), currentMethodSym); JCStatement init = make. VarDef(itvar, make.App(make.Select(tree.expr, iterator) .setType(types.erasure(iterator.type)))); Symbol hasNext = lookupMethod(tree.expr.pos(), names.hasNext, itvar.type, List.nil()); JCMethodInvocation cond = make.App(make.Select(make.Ident(itvar), hasNext)); Symbol next = lookupMethod(tree.expr.pos(), names.next, itvar.type, List.nil()); JCExpression vardefinit = make.App(make.Select(make.Ident(itvar), next)); if (tree.var.type.isPrimitive()) vardefinit = make.TypeCast(types.cvarUpperBound(iteratorTarget), vardefinit); else vardefinit = make.TypeCast(tree.var.type, vardefinit); JCVariableDecl indexDef = (JCVariableDecl)make.VarDef(tree.var.mods, tree.var.name, tree.var.vartype, vardefinit).setType(tree.var.type); indexDef.sym = tree.var.sym; JCBlock body = make.Block(0, List.of(indexDef, tree.body)); body.endpos = TreeInfo.endPos(tree.body); result = translate(make. ForLoop(List.of(init), cond, List.nil(), body)); patchTargets(body, tree, result); } public void visitVarDef(JCVariableDecl tree) { MethodSymbol oldMethodSym = currentMethodSym; tree.mods = translate(tree.mods); tree.vartype = translate(tree.vartype); if (currentMethodSym == null) { // A class or instance field initializer. currentMethodSym = new MethodSymbol((tree.mods.flags&STATIC) | BLOCK, names.empty, null, currentClass); } if (tree.init != null) tree.init = translate(tree.init, tree.type); result = tree; currentMethodSym = oldMethodSym; } public void visitBlock(JCBlock tree) { MethodSymbol oldMethodSym = currentMethodSym; if (currentMethodSym == null) { // Block is a static or instance initializer. currentMethodSym = new MethodSymbol(tree.flags | BLOCK, names.empty, null, currentClass); } super.visitBlock(tree); currentMethodSym = oldMethodSym; } 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); if (tree.cond != null) tree.cond = translate(tree.cond, syms.booleanType); tree.step = translate(tree.step); tree.body = translate(tree.body); result = tree; } public void visitReturn(JCReturn tree) { if (tree.expr != null) tree.expr = translate(tree.expr, types.erasure(currentMethodDef .restype.type)); result = tree; } public void visitSwitch(JCSwitch tree) { Type selsuper = types.supertype(tree.selector.type); boolean enumSwitch = selsuper != null && (tree.selector.type.tsym.flags() & ENUM) != 0; boolean stringSwitch = selsuper != null && types.isSameType(tree.selector.type, syms.stringType); Type target = enumSwitch ? tree.selector.type : (stringSwitch? syms.stringType : syms.intType); tree.selector = translate(tree.selector, target); tree.cases = translateCases(tree.cases); if (enumSwitch) { result = visitEnumSwitch(tree); } else if (stringSwitch) { result = visitStringSwitch(tree); } else { result = tree; } } public JCTree visitEnumSwitch(JCSwitch tree) { TypeSymbol enumSym = tree.selector.type.tsym; EnumMapping map = mapForEnum(tree.pos(), enumSym); make_at(tree.pos()); Symbol ordinalMethod = lookupMethod(tree.pos(), names.ordinal, tree.selector.type, List.nil()); JCArrayAccess selector = make.Indexed(map.mapVar, make.App(make.Select(tree.selector, ordinalMethod))); ListBuffer cases = new ListBuffer<>(); for (JCCase c : tree.cases) { if (c.pat != null) { VarSymbol label = (VarSymbol)TreeInfo.symbol(c.pat); JCLiteral pat = map.forConstant(label); cases.append(make.Case(pat, c.stats)); } else { cases.append(c); } } JCSwitch enumSwitch = make.Switch(selector, cases.toList()); patchTargets(enumSwitch, tree, enumSwitch); return enumSwitch; } public JCTree visitStringSwitch(JCSwitch tree) { List caseList = tree.getCases(); int alternatives = caseList.size(); if (alternatives == 0) { // Strange but legal possibility return make.at(tree.pos()).Exec(attr.makeNullCheck(tree.getExpression())); } else { /* * The general approach used is to translate a single * string switch statement into a series of two chained * switch statements: the first a synthesized statement * switching on the argument string's hash value and * computing a string's position in the list of original * case labels, if any, followed by a second switch on the * computed integer value. The second switch has the same * code structure as the original string switch statement * except that the string case labels are replaced with * positional integer constants starting at 0. * * The first switch statement can be thought of as an * inlined map from strings to their position in the case * label list. An alternate implementation would use an * actual Map for this purpose, as done for enum switches. * * With some additional effort, it would be possible to * use a single switch statement on the hash code of the * argument, but care would need to be taken to preserve * the proper control flow in the presence of hash * collisions and other complications, such as * fallthroughs. Switch statements with one or two * alternatives could also be specially translated into * if-then statements to omit the computation of the hash * code. * * The generated code assumes that the hashing algorithm * of String is the same in the compilation environment as * in the environment the code will run in. The string * hashing algorithm in the SE JDK has been unchanged * since at least JDK 1.2. Since the algorithm has been * specified since that release as well, it is very * unlikely to be changed in the future. * * Different hashing algorithms, such as the length of the * strings or a perfect hashing algorithm over the * particular set of case labels, could potentially be * used instead of String.hashCode. */ ListBuffer stmtList = new ListBuffer<>(); // Map from String case labels to their original position in // the list of case labels. Map caseLabelToPosition = new LinkedHashMap<>(alternatives + 1, 1.0f); // Map of hash codes to the string case labels having that hashCode. Map> hashToString = new LinkedHashMap<>(alternatives + 1, 1.0f); int casePosition = 0; for(JCCase oneCase : caseList) { JCExpression expression = oneCase.getExpression(); if (expression != null) { // expression for a "default" case is null String labelExpr = (String) expression.type.constValue(); Integer mapping = caseLabelToPosition.put(labelExpr, casePosition); Assert.checkNull(mapping); int hashCode = labelExpr.hashCode(); Set stringSet = hashToString.get(hashCode); if (stringSet == null) { stringSet = new LinkedHashSet<>(1, 1.0f); stringSet.add(labelExpr); hashToString.put(hashCode, stringSet); } else { boolean added = stringSet.add(labelExpr); Assert.check(added); } } casePosition++; } // Synthesize a switch statement that has the effect of // mapping from a string to the integer position of that // string in the list of case labels. This is done by // switching on the hashCode of the string followed by an // if-then-else chain comparing the input for equality // with all the case labels having that hash value. /* * s$ = top of stack; * tmp$ = -1; * switch($s.hashCode()) { * case caseLabel.hashCode: * if (s$.equals("caseLabel_1") * tmp$ = caseLabelToPosition("caseLabel_1"); * else if (s$.equals("caseLabel_2")) * tmp$ = caseLabelToPosition("caseLabel_2"); * ... * break; * ... * } */ VarSymbol dollar_s = new VarSymbol(FINAL|SYNTHETIC, names.fromString("s" + tree.pos + target.syntheticNameChar()), syms.stringType, currentMethodSym); stmtList.append(make.at(tree.pos()).VarDef(dollar_s, tree.getExpression()).setType(dollar_s.type)); VarSymbol dollar_tmp = new VarSymbol(SYNTHETIC, names.fromString("tmp" + tree.pos + target.syntheticNameChar()), syms.intType, currentMethodSym); JCVariableDecl dollar_tmp_def = (JCVariableDecl)make.VarDef(dollar_tmp, make.Literal(INT, -1)).setType(dollar_tmp.type); dollar_tmp_def.init.type = dollar_tmp.type = syms.intType; stmtList.append(dollar_tmp_def); ListBuffer caseBuffer = new ListBuffer<>(); // hashCode will trigger nullcheck on original switch expression JCMethodInvocation hashCodeCall = makeCall(make.Ident(dollar_s), names.hashCode, List.nil()).setType(syms.intType); JCSwitch switch1 = make.Switch(hashCodeCall, caseBuffer.toList()); for(Map.Entry> entry : hashToString.entrySet()) { int hashCode = entry.getKey(); Set stringsWithHashCode = entry.getValue(); Assert.check(stringsWithHashCode.size() >= 1); JCStatement elsepart = null; for(String caseLabel : stringsWithHashCode ) { JCMethodInvocation stringEqualsCall = makeCall(make.Ident(dollar_s), names.equals, List.of(make.Literal(caseLabel))); elsepart = make.If(stringEqualsCall, make.Exec(make.Assign(make.Ident(dollar_tmp), make.Literal(caseLabelToPosition.get(caseLabel))). setType(dollar_tmp.type)), elsepart); } ListBuffer lb = new ListBuffer<>(); JCBreak breakStmt = make.Break(null); breakStmt.target = switch1; lb.append(elsepart).append(breakStmt); caseBuffer.append(make.Case(make.Literal(hashCode), lb.toList())); } switch1.cases = caseBuffer.toList(); stmtList.append(switch1); // Make isomorphic switch tree replacing string labels // with corresponding integer ones from the label to // position map. ListBuffer lb = new ListBuffer<>(); JCSwitch switch2 = make.Switch(make.Ident(dollar_tmp), lb.toList()); for(JCCase oneCase : caseList ) { // Rewire up old unlabeled break statements to the // replacement switch being created. patchTargets(oneCase, tree, switch2); boolean isDefault = (oneCase.getExpression() == null); JCExpression caseExpr; if (isDefault) caseExpr = null; else { caseExpr = make.Literal(caseLabelToPosition.get((String)TreeInfo.skipParens(oneCase. getExpression()). type.constValue())); } lb.append(make.Case(caseExpr, oneCase.getStatements())); } switch2.cases = lb.toList(); stmtList.append(switch2); return make.Block(0L, stmtList.toList()); } } public void visitNewArray(JCNewArray tree) { tree.elemtype = translate(tree.elemtype); for (List t = tree.dims; t.tail != null; t = t.tail) if (t.head != null) t.head = translate(t.head, syms.intType); tree.elems = translate(tree.elems, types.elemtype(tree.type)); result = tree; } public void visitSelect(JCFieldAccess tree) { // need to special case-access of the form C.super.x // these will always need an access method, unless C // is a default interface subclassed by the current class. boolean qualifiedSuperAccess = tree.selected.hasTag(SELECT) && TreeInfo.name(tree.selected) == names._super && !types.isDirectSuperInterface(((JCFieldAccess)tree.selected).selected.type.tsym, currentClass); tree.selected = translate(tree.selected); if (tree.name == names._class) { result = classOf(tree.selected); } else if (tree.name == names._super && types.isDirectSuperInterface(tree.selected.type.tsym, currentClass)) { //default super call!! Not a classic qualified super call TypeSymbol supSym = tree.selected.type.tsym; Assert.checkNonNull(types.asSuper(currentClass.type, supSym)); result = tree; } else if (tree.name == names._this || tree.name == names._super) { result = makeThis(tree.pos(), tree.selected.type.tsym); } else result = access(tree.sym, tree, enclOp, qualifiedSuperAccess); } public void visitLetExpr(LetExpr tree) { tree.defs = translateVarDefs(tree.defs); tree.expr = translate(tree.expr, tree.type); result = tree; } // There ought to be nothing to rewrite here; // we don't generate code. public void visitAnnotation(JCAnnotation tree) { result = tree; } @Override public void visitTry(JCTry tree) { if (tree.resources.nonEmpty()) { result = makeTwrTry(tree); return; } boolean hasBody = tree.body.getStatements().nonEmpty(); boolean hasCatchers = tree.catchers.nonEmpty(); boolean hasFinally = tree.finalizer != null && tree.finalizer.getStatements().nonEmpty(); if (!hasCatchers && !hasFinally) { result = translate(tree.body); return; } if (!hasBody) { if (hasFinally) { result = translate(tree.finalizer); } else { result = translate(tree.body); } return; } // no optimizations possible super.visitTry(tree); } /************************************************************************** * main method *************************************************************************/ /** Translate a toplevel class and return a list consisting of * the translated class and translated versions of all inner classes. * @param env The attribution environment current at the class definition. * We need this for resolving some additional symbols. * @param cdef The tree representing the class definition. */ public List translateTopLevelClass(Env env, JCTree cdef, TreeMaker make) { ListBuffer translated = null; try { attrEnv = env; this.make = make; endPosTable = env.toplevel.endPositions; currentClass = null; currentMethodDef = null; outermostClassDef = (cdef.hasTag(CLASSDEF)) ? (JCClassDecl)cdef : null; outermostMemberDef = null; this.translated = new ListBuffer<>(); classdefs = new HashMap<>(); actualSymbols = new HashMap<>(); freevarCache = new HashMap<>(); proxies = WriteableScope.create(syms.noSymbol); twrVars = WriteableScope.create(syms.noSymbol); outerThisStack = List.nil(); accessNums = new HashMap<>(); accessSyms = new HashMap<>(); accessConstrs = new HashMap<>(); accessConstrTags = List.nil(); accessed = new ListBuffer<>(); translate(cdef, (JCExpression)null); for (List l = accessed.toList(); l.nonEmpty(); l = l.tail) makeAccessible(l.head); for (EnumMapping map : enumSwitchMap.values()) map.translate(); checkConflicts(this.translated.toList()); checkAccessConstructorTags(); translated = this.translated; } finally { // note that recursive invocations of this method fail hard attrEnv = null; this.make = null; endPosTable = null; currentClass = null; currentMethodDef = null; outermostClassDef = null; outermostMemberDef = null; this.translated = null; classdefs = null; actualSymbols = null; freevarCache = null; proxies = null; outerThisStack = null; accessNums = null; accessSyms = null; accessConstrs = null; accessConstrTags = null; accessed = null; enumSwitchMap.clear(); assertionsDisabledClassCache = null; } return translated.toList(); } }