aoqi@0: /*
aoqi@0:  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: package com.sun.tools.javac.jvm;
aoqi@0: 
aoqi@0: import com.sun.tools.javac.code.*;
aoqi@0: import com.sun.tools.javac.code.Symbol.*;
aoqi@0: import com.sun.tools.javac.code.Type.*;
aoqi@0: import com.sun.tools.javac.jvm.Code.*;
aoqi@0: import com.sun.tools.javac.tree.JCTree;
aoqi@0: import com.sun.tools.javac.util.Assert;
aoqi@0: 
aoqi@0: import static com.sun.tools.javac.jvm.ByteCodes.*;
aoqi@0: 
aoqi@0: /** A helper class for code generation. Items are objects
aoqi@0:  *  that stand for addressable entities in the bytecode. Each item
aoqi@0:  *  supports a fixed protocol for loading the item on the stack, storing
aoqi@0:  *  into it, converting it into a jump condition, and several others.
aoqi@0:  *  There are many individual forms of items, such as local, static,
aoqi@0:  *  indexed, or instance variables, values on the top of stack, the
aoqi@0:  *  special values this or super, etc. Individual items are represented as
aoqi@0:  *  inner classes in class Items.
aoqi@0:  *
aoqi@0:  *  <p><b>This is NOT part of any supported API.
aoqi@0:  *  If you write code that depends on this, you do so at your own risk.
aoqi@0:  *  This code and its internal interfaces are subject to change or
aoqi@0:  *  deletion without notice.</b>
aoqi@0:  */
aoqi@0: public class Items {
aoqi@0: 
aoqi@0:     /** The current constant pool.
aoqi@0:      */
aoqi@0:     Pool pool;
aoqi@0: 
aoqi@0:     /** The current code buffer.
aoqi@0:      */
aoqi@0:     Code code;
aoqi@0: 
aoqi@0:     /** The current symbol table.
aoqi@0:      */
aoqi@0:     Symtab syms;
aoqi@0: 
aoqi@0:     /** Type utilities. */
aoqi@0:     Types types;
aoqi@0: 
aoqi@0:     /** Items that exist only once (flyweight pattern).
aoqi@0:      */
aoqi@0:     private final Item voidItem;
aoqi@0:     private final Item thisItem;
aoqi@0:     private final Item superItem;
aoqi@0:     private final Item[] stackItem = new Item[TypeCodeCount];
aoqi@0: 
aoqi@0:     public Items(Pool pool, Code code, Symtab syms, Types types) {
aoqi@0:         this.code = code;
aoqi@0:         this.pool = pool;
aoqi@0:         this.types = types;
aoqi@0:         voidItem = new Item(VOIDcode) {
aoqi@0:                 public String toString() { return "void"; }
aoqi@0:             };
aoqi@0:         thisItem = new SelfItem(false);
aoqi@0:         superItem = new SelfItem(true);
aoqi@0:         for (int i = 0; i < VOIDcode; i++) stackItem[i] = new StackItem(i);
aoqi@0:         stackItem[VOIDcode] = voidItem;
aoqi@0:         this.syms = syms;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make a void item
aoqi@0:      */
aoqi@0:     Item makeVoidItem() {
aoqi@0:         return voidItem;
aoqi@0:     }
aoqi@0:     /** Make an item representing `this'.
aoqi@0:      */
aoqi@0:     Item makeThisItem() {
aoqi@0:         return thisItem;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing `super'.
aoqi@0:      */
aoqi@0:     Item makeSuperItem() {
aoqi@0:         return superItem;
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a value on stack.
aoqi@0:      *  @param type    The value's type.
aoqi@0:      */
aoqi@0:     Item makeStackItem(Type type) {
aoqi@0:         return stackItem[Code.typecode(type)];
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a dynamically invoked method.
aoqi@0:      *  @param member   The represented symbol.
aoqi@0:      */
aoqi@0:     Item makeDynamicItem(Symbol member) {
aoqi@0:         return new DynamicItem(member);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing an indexed expression.
aoqi@0:      *  @param type    The expression's type.
aoqi@0:      */
aoqi@0:     Item makeIndexedItem(Type type) {
aoqi@0:         return new IndexedItem(type);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a local variable.
aoqi@0:      *  @param v    The represented variable.
aoqi@0:      */
aoqi@0:     LocalItem makeLocalItem(VarSymbol v) {
aoqi@0:         return new LocalItem(v.erasure(types), v.adr);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a local anonymous variable.
aoqi@0:      *  @param type  The represented variable's type.
aoqi@0:      *  @param reg   The represented variable's register.
aoqi@0:      */
aoqi@0:     private LocalItem makeLocalItem(Type type, int reg) {
aoqi@0:         return new LocalItem(type, reg);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a static variable or method.
aoqi@0:      *  @param member   The represented symbol.
aoqi@0:      */
aoqi@0:     Item makeStaticItem(Symbol member) {
aoqi@0:         return new StaticItem(member);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing an instance variable or method.
aoqi@0:      *  @param member       The represented symbol.
aoqi@0:      *  @param nonvirtual   Is the reference not virtual? (true for constructors
aoqi@0:      *                      and private members).
aoqi@0:      */
aoqi@0:     Item makeMemberItem(Symbol member, boolean nonvirtual) {
aoqi@0:         return new MemberItem(member, nonvirtual);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a literal.
aoqi@0:      *  @param type     The literal's type.
aoqi@0:      *  @param value    The literal's value.
aoqi@0:      */
aoqi@0:     Item makeImmediateItem(Type type, Object value) {
aoqi@0:         return new ImmediateItem(type, value);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing an assignment expression.
aoqi@0:      *  @param lhs      The item representing the assignment's left hand side.
aoqi@0:      */
aoqi@0:     Item makeAssignItem(Item lhs) {
aoqi@0:         return new AssignItem(lhs);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a conditional or unconditional jump.
aoqi@0:      *  @param opcode      The jump's opcode.
aoqi@0:      *  @param trueJumps   A chain encomassing all jumps that can be taken
aoqi@0:      *                     if the condition evaluates to true.
aoqi@0:      *  @param falseJumps  A chain encomassing all jumps that can be taken
aoqi@0:      *                     if the condition evaluates to false.
aoqi@0:      */
aoqi@0:     CondItem makeCondItem(int opcode, Chain trueJumps, Chain falseJumps) {
aoqi@0:         return new CondItem(opcode, trueJumps, falseJumps);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** Make an item representing a conditional or unconditional jump.
aoqi@0:      *  @param opcode      The jump's opcode.
aoqi@0:      */
aoqi@0:     CondItem makeCondItem(int opcode) {
aoqi@0:         return makeCondItem(opcode, null, null);
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** The base class of all items, which implements default behavior.
aoqi@0:      */
aoqi@0:     abstract class Item {
aoqi@0: 
aoqi@0:         /** The type code of values represented by this item.
aoqi@0:          */
aoqi@0:         int typecode;
aoqi@0: 
aoqi@0:         Item(int typecode) {
aoqi@0:             this.typecode = typecode;
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Generate code to load this item onto stack.
aoqi@0:          */
aoqi@0:         Item load() {
aoqi@0:             throw new AssertionError();
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Generate code to store top of stack into this item.
aoqi@0:          */
aoqi@0:         void store() {
aoqi@0:             throw new AssertionError("store unsupported: " + this);
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Generate code to invoke method represented by this item.
aoqi@0:          */
aoqi@0:         Item invoke() {
aoqi@0:             throw new AssertionError(this);
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Generate code to use this item twice.
aoqi@0:          */
aoqi@0:         void duplicate() {}
aoqi@0: 
aoqi@0:         /** Generate code to avoid having to use this item.
aoqi@0:          */
aoqi@0:         void drop() {}
aoqi@0: 
aoqi@0:         /** Generate code to stash a copy of top of stack - of typecode toscode -
aoqi@0:          *  under this item.
aoqi@0:          */
aoqi@0:         void stash(int toscode) {
aoqi@0:             stackItem[toscode].duplicate();
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Generate code to turn item into a testable condition.
aoqi@0:          */
aoqi@0:         CondItem mkCond() {
aoqi@0:             load();
aoqi@0:             return makeCondItem(ifne);
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Generate code to coerce item to given type code.
aoqi@0:          *  @param targetcode    The type code to coerce to.
aoqi@0:          */
aoqi@0:         Item coerce(int targetcode) {
aoqi@0:             if (typecode == targetcode)
aoqi@0:                 return this;
aoqi@0:             else {
aoqi@0:                 load();
aoqi@0:                 int typecode1 = Code.truncate(typecode);
aoqi@0:                 int targetcode1 = Code.truncate(targetcode);
aoqi@0:                 if (typecode1 != targetcode1) {
aoqi@0:                     int offset = targetcode1 > typecode1 ? targetcode1 - 1
aoqi@0:                         : targetcode1;
aoqi@0:                     code.emitop0(i2l + typecode1 * 3 + offset);
aoqi@0:                 }
aoqi@0:                 if (targetcode != targetcode1) {
aoqi@0:                     code.emitop0(int2byte + targetcode - BYTEcode);
aoqi@0:                 }
aoqi@0:                 return stackItem[targetcode];
aoqi@0:             }
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Generate code to coerce item to given type.
aoqi@0:          *  @param targettype    The type to coerce to.
aoqi@0:          */
aoqi@0:         Item coerce(Type targettype) {
aoqi@0:             return coerce(Code.typecode(targettype));
aoqi@0:         }
aoqi@0: 
aoqi@0:         /** Return the width of this item on stack as a number of words.
aoqi@0:          */
aoqi@0:         int width() {
aoqi@0:             return 0;
aoqi@0:         }
aoqi@0: 
aoqi@0:         public abstract String toString();
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing a value on stack.
aoqi@0:      */
aoqi@0:     class StackItem extends Item {
aoqi@0: 
aoqi@0:         StackItem(int typecode) {
aoqi@0:             super(typecode);
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             return this;
aoqi@0:         }
aoqi@0: 
aoqi@0:         void duplicate() {
aoqi@0:             code.emitop0(width() == 2 ? dup2 : dup);
aoqi@0:         }
aoqi@0: 
aoqi@0:         void drop() {
aoqi@0:             code.emitop0(width() == 2 ? pop2 : pop);
aoqi@0:         }
aoqi@0: 
aoqi@0:         void stash(int toscode) {
aoqi@0:             code.emitop0(
aoqi@0:                 (width() == 2 ? dup_x2 : dup_x1) + 3 * (Code.width(toscode) - 1));
aoqi@0:         }
aoqi@0: 
aoqi@0:         int width() {
aoqi@0:             return Code.width(typecode);
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "stack(" + typecodeNames[typecode] + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing an indexed expression.
aoqi@0:      */
aoqi@0:     class IndexedItem extends Item {
aoqi@0: 
aoqi@0:         IndexedItem(Type type) {
aoqi@0:             super(Code.typecode(type));
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             code.emitop0(iaload + typecode);
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         void store() {
aoqi@0:             code.emitop0(iastore + typecode);
aoqi@0:         }
aoqi@0: 
aoqi@0:         void duplicate() {
aoqi@0:             code.emitop0(dup2);
aoqi@0:         }
aoqi@0: 
aoqi@0:         void drop() {
aoqi@0:             code.emitop0(pop2);
aoqi@0:         }
aoqi@0: 
aoqi@0:         void stash(int toscode) {
aoqi@0:             code.emitop0(dup_x2 + 3 * (Code.width(toscode) - 1));
aoqi@0:         }
aoqi@0: 
aoqi@0:         int width() {
aoqi@0:             return 2;
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "indexed(" + ByteCodes.typecodeNames[typecode] + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing `this' or `super'.
aoqi@0:      */
aoqi@0:     class SelfItem extends Item {
aoqi@0: 
aoqi@0:         /** Flag which determines whether this item represents `this' or `super'.
aoqi@0:          */
aoqi@0:         boolean isSuper;
aoqi@0: 
aoqi@0:         SelfItem(boolean isSuper) {
aoqi@0:             super(OBJECTcode);
aoqi@0:             this.isSuper = isSuper;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             code.emitop0(aload_0);
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return isSuper ? "super" : "this";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing a local variable.
aoqi@0:      */
aoqi@0:     class LocalItem extends Item {
aoqi@0: 
aoqi@0:         /** The variable's register.
aoqi@0:          */
aoqi@0:         int reg;
aoqi@0: 
aoqi@0:         /** The variable's type.
aoqi@0:          */
aoqi@0:         Type type;
aoqi@0: 
aoqi@0:         LocalItem(Type type, int reg) {
aoqi@0:             super(Code.typecode(type));
aoqi@0:             Assert.check(reg >= 0);
aoqi@0:             this.type = type;
aoqi@0:             this.reg = reg;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             if (reg <= 3)
aoqi@0:                 code.emitop0(iload_0 + Code.truncate(typecode) * 4 + reg);
aoqi@0:             else
aoqi@0:                 code.emitop1w(iload + Code.truncate(typecode), reg);
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         void store() {
aoqi@0:             if (reg <= 3)
aoqi@0:                 code.emitop0(istore_0 + Code.truncate(typecode) * 4 + reg);
aoqi@0:             else
aoqi@0:                 code.emitop1w(istore + Code.truncate(typecode), reg);
aoqi@0:             code.setDefined(reg);
aoqi@0:         }
aoqi@0: 
aoqi@0:         void incr(int x) {
aoqi@0:             if (typecode == INTcode && x >= -32768 && x <= 32767) {
aoqi@0:                 code.emitop1w(iinc, reg, x);
aoqi@0:             } else {
aoqi@0:                 load();
aoqi@0:                 if (x >= 0) {
aoqi@0:                     makeImmediateItem(syms.intType, x).load();
aoqi@0:                     code.emitop0(iadd);
aoqi@0:                 } else {
aoqi@0:                     makeImmediateItem(syms.intType, -x).load();
aoqi@0:                     code.emitop0(isub);
aoqi@0:                 }
aoqi@0:                 makeStackItem(syms.intType).coerce(typecode);
aoqi@0:                 store();
aoqi@0:             }
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "localItem(type=" + type + "; reg=" + reg + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing a static variable or method.
aoqi@0:      */
aoqi@0:     class StaticItem extends Item {
aoqi@0: 
aoqi@0:         /** The represented symbol.
aoqi@0:          */
aoqi@0:         Symbol member;
aoqi@0: 
aoqi@0:         StaticItem(Symbol member) {
aoqi@0:             super(Code.typecode(member.erasure(types)));
aoqi@0:             this.member = member;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             code.emitop2(getstatic, pool.put(member));
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         void store() {
aoqi@0:             code.emitop2(putstatic, pool.put(member));
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item invoke() {
aoqi@0:             MethodType mtype = (MethodType)member.erasure(types);
aoqi@0:             int rescode = Code.typecode(mtype.restype);
aoqi@0:             code.emitInvokestatic(pool.put(member), mtype);
aoqi@0:             return stackItem[rescode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "static(" + member + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing a dynamic call site.
aoqi@0:      */
aoqi@0:     class DynamicItem extends StaticItem {
aoqi@0:         DynamicItem(Symbol member) {
aoqi@0:             super(member);
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             assert false;
aoqi@0:             return null;
aoqi@0:         }
aoqi@0: 
aoqi@0:         void store() {
aoqi@0:             assert false;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item invoke() {
aoqi@0:             // assert target.hasNativeInvokeDynamic();
aoqi@0:             MethodType mtype = (MethodType)member.erasure(types);
aoqi@0:             int rescode = Code.typecode(mtype.restype);
aoqi@0:             code.emitInvokedynamic(pool.put(member), mtype);
aoqi@0:             return stackItem[rescode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "dynamic(" + member + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing an instance variable or method.
aoqi@0:      */
aoqi@0:     class MemberItem extends Item {
aoqi@0: 
aoqi@0:         /** The represented symbol.
aoqi@0:          */
aoqi@0:         Symbol member;
aoqi@0: 
aoqi@0:         /** Flag that determines whether or not access is virtual.
aoqi@0:          */
aoqi@0:         boolean nonvirtual;
aoqi@0: 
aoqi@0:         MemberItem(Symbol member, boolean nonvirtual) {
aoqi@0:             super(Code.typecode(member.erasure(types)));
aoqi@0:             this.member = member;
aoqi@0:             this.nonvirtual = nonvirtual;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             code.emitop2(getfield, pool.put(member));
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         void store() {
aoqi@0:             code.emitop2(putfield, pool.put(member));
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item invoke() {
aoqi@0:             MethodType mtype = (MethodType)member.externalType(types);
aoqi@0:             int rescode = Code.typecode(mtype.restype);
aoqi@0:             if ((member.owner.flags() & Flags.INTERFACE) != 0 && !nonvirtual) {
aoqi@0:                 code.emitInvokeinterface(pool.put(member), mtype);
aoqi@0:             } else if (nonvirtual) {
aoqi@0:                 code.emitInvokespecial(pool.put(member), mtype);
aoqi@0:             } else {
aoqi@0:                 code.emitInvokevirtual(pool.put(member), mtype);
aoqi@0:             }
aoqi@0:             return stackItem[rescode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         void duplicate() {
aoqi@0:             stackItem[OBJECTcode].duplicate();
aoqi@0:         }
aoqi@0: 
aoqi@0:         void drop() {
aoqi@0:             stackItem[OBJECTcode].drop();
aoqi@0:         }
aoqi@0: 
aoqi@0:         void stash(int toscode) {
aoqi@0:             stackItem[OBJECTcode].stash(toscode);
aoqi@0:         }
aoqi@0: 
aoqi@0:         int width() {
aoqi@0:             return 1;
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "member(" + member + (nonvirtual ? " nonvirtual)" : ")");
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing a literal.
aoqi@0:      */
aoqi@0:     class ImmediateItem extends Item {
aoqi@0: 
aoqi@0:         /** The literal's value.
aoqi@0:          */
aoqi@0:         Object value;
aoqi@0: 
aoqi@0:         ImmediateItem(Type type, Object value) {
aoqi@0:             super(Code.typecode(type));
aoqi@0:             this.value = value;
aoqi@0:         }
aoqi@0: 
aoqi@0:         private void ldc() {
aoqi@0:             int idx = pool.put(value);
aoqi@0:             if (typecode == LONGcode || typecode == DOUBLEcode) {
aoqi@0:                 code.emitop2(ldc2w, idx);
aoqi@0:             } else {
aoqi@0:                 code.emitLdc(idx);
aoqi@0:             }
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             switch (typecode) {
aoqi@0:             case INTcode: case BYTEcode: case SHORTcode: case CHARcode:
aoqi@0:                 int ival = ((Number)value).intValue();
aoqi@0:                 if (-1 <= ival && ival <= 5)
aoqi@0:                     code.emitop0(iconst_0 + ival);
aoqi@0:                 else if (Byte.MIN_VALUE <= ival && ival <= Byte.MAX_VALUE)
aoqi@0:                     code.emitop1(bipush, ival);
aoqi@0:                 else if (Short.MIN_VALUE <= ival && ival <= Short.MAX_VALUE)
aoqi@0:                     code.emitop2(sipush, ival);
aoqi@0:                 else
aoqi@0:                     ldc();
aoqi@0:                 break;
aoqi@0:             case LONGcode:
aoqi@0:                 long lval = ((Number)value).longValue();
aoqi@0:                 if (lval == 0 || lval == 1)
aoqi@0:                     code.emitop0(lconst_0 + (int)lval);
aoqi@0:                 else
aoqi@0:                     ldc();
aoqi@0:                 break;
aoqi@0:             case FLOATcode:
aoqi@0:                 float fval = ((Number)value).floatValue();
aoqi@0:                 if (isPosZero(fval) || fval == 1.0 || fval == 2.0)
aoqi@0:                     code.emitop0(fconst_0 + (int)fval);
aoqi@0:                 else {
aoqi@0:                     ldc();
aoqi@0:                 }
aoqi@0:                 break;
aoqi@0:             case DOUBLEcode:
aoqi@0:                 double dval = ((Number)value).doubleValue();
aoqi@0:                 if (isPosZero(dval) || dval == 1.0)
aoqi@0:                     code.emitop0(dconst_0 + (int)dval);
aoqi@0:                 else
aoqi@0:                     ldc();
aoqi@0:                 break;
aoqi@0:             case OBJECTcode:
aoqi@0:                 ldc();
aoqi@0:                 break;
aoqi@0:             default:
aoqi@0:                 Assert.error();
aoqi@0:             }
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0:         //where
aoqi@0:             /** Return true iff float number is positive 0.
aoqi@0:              */
aoqi@0:             private boolean isPosZero(float x) {
aoqi@0:                 return x == 0.0f && 1.0f / x > 0.0f;
aoqi@0:             }
aoqi@0:             /** Return true iff double number is positive 0.
aoqi@0:              */
aoqi@0:             private boolean isPosZero(double x) {
aoqi@0:                 return x == 0.0d && 1.0d / x > 0.0d;
aoqi@0:             }
aoqi@0: 
aoqi@0:         CondItem mkCond() {
aoqi@0:             int ival = ((Number)value).intValue();
aoqi@0:             return makeCondItem(ival != 0 ? goto_ : dontgoto);
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item coerce(int targetcode) {
aoqi@0:             if (typecode == targetcode) {
aoqi@0:                 return this;
aoqi@0:             } else {
aoqi@0:                 switch (targetcode) {
aoqi@0:                 case INTcode:
aoqi@0:                     if (Code.truncate(typecode) == INTcode)
aoqi@0:                         return this;
aoqi@0:                     else
aoqi@0:                         return new ImmediateItem(
aoqi@0:                             syms.intType,
aoqi@0:                             ((Number)value).intValue());
aoqi@0:                 case LONGcode:
aoqi@0:                     return new ImmediateItem(
aoqi@0:                         syms.longType,
aoqi@0:                         ((Number)value).longValue());
aoqi@0:                 case FLOATcode:
aoqi@0:                     return new ImmediateItem(
aoqi@0:                         syms.floatType,
aoqi@0:                         ((Number)value).floatValue());
aoqi@0:                 case DOUBLEcode:
aoqi@0:                     return new ImmediateItem(
aoqi@0:                         syms.doubleType,
aoqi@0:                         ((Number)value).doubleValue());
aoqi@0:                 case BYTEcode:
aoqi@0:                     return new ImmediateItem(
aoqi@0:                         syms.byteType,
aoqi@0:                         (int)(byte)((Number)value).intValue());
aoqi@0:                 case CHARcode:
aoqi@0:                     return new ImmediateItem(
aoqi@0:                         syms.charType,
aoqi@0:                         (int)(char)((Number)value).intValue());
aoqi@0:                 case SHORTcode:
aoqi@0:                     return new ImmediateItem(
aoqi@0:                         syms.shortType,
aoqi@0:                         (int)(short)((Number)value).intValue());
aoqi@0:                 default:
aoqi@0:                     return super.coerce(targetcode);
aoqi@0:                 }
aoqi@0:             }
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "immediate(" + value + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing an assignment expressions.
aoqi@0:      */
aoqi@0:     class AssignItem extends Item {
aoqi@0: 
aoqi@0:         /** The item representing the assignment's left hand side.
aoqi@0:          */
aoqi@0:         Item lhs;
aoqi@0: 
aoqi@0:         AssignItem(Item lhs) {
aoqi@0:             super(lhs.typecode);
aoqi@0:             this.lhs = lhs;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             lhs.stash(typecode);
aoqi@0:             lhs.store();
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         void duplicate() {
aoqi@0:             load().duplicate();
aoqi@0:         }
aoqi@0: 
aoqi@0:         void drop() {
aoqi@0:             lhs.store();
aoqi@0:         }
aoqi@0: 
aoqi@0:         void stash(int toscode) {
aoqi@0:             Assert.error();
aoqi@0:         }
aoqi@0: 
aoqi@0:         int width() {
aoqi@0:             return lhs.width() + Code.width(typecode);
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "assign(lhs = " + lhs + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /** An item representing a conditional or unconditional jump.
aoqi@0:      */
aoqi@0:     class CondItem extends Item {
aoqi@0: 
aoqi@0:         /** A chain encomassing all jumps that can be taken
aoqi@0:          *  if the condition evaluates to true.
aoqi@0:          */
aoqi@0:         Chain trueJumps;
aoqi@0: 
aoqi@0:         /** A chain encomassing all jumps that can be taken
aoqi@0:          *  if the condition evaluates to false.
aoqi@0:          */
aoqi@0:         Chain falseJumps;
aoqi@0: 
aoqi@0:         /** The jump's opcode.
aoqi@0:          */
aoqi@0:         int opcode;
aoqi@0: 
aoqi@0:         /*
aoqi@0:          *  An abstract syntax tree of this item. It is needed
aoqi@0:          *  for branch entries in 'CharacterRangeTable' attribute.
aoqi@0:          */
aoqi@0:         JCTree tree;
aoqi@0: 
aoqi@0:         CondItem(int opcode, Chain truejumps, Chain falsejumps) {
aoqi@0:             super(BYTEcode);
aoqi@0:             this.opcode = opcode;
aoqi@0:             this.trueJumps = truejumps;
aoqi@0:             this.falseJumps = falsejumps;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Item load() {
aoqi@0:             Chain trueChain = null;
aoqi@0:             Chain falseChain = jumpFalse();
aoqi@0:             if (!isFalse()) {
aoqi@0:                 code.resolve(trueJumps);
aoqi@0:                 code.emitop0(iconst_1);
aoqi@0:                 trueChain = code.branch(goto_);
aoqi@0:             }
aoqi@0:             if (falseChain != null) {
aoqi@0:                 code.resolve(falseChain);
aoqi@0:                 code.emitop0(iconst_0);
aoqi@0:             }
aoqi@0:             code.resolve(trueChain);
aoqi@0:             return stackItem[typecode];
aoqi@0:         }
aoqi@0: 
aoqi@0:         void duplicate() {
aoqi@0:             load().duplicate();
aoqi@0:         }
aoqi@0: 
aoqi@0:         void drop() {
aoqi@0:             load().drop();
aoqi@0:         }
aoqi@0: 
aoqi@0:         void stash(int toscode) {
aoqi@0:             Assert.error();
aoqi@0:         }
aoqi@0: 
aoqi@0:         CondItem mkCond() {
aoqi@0:             return this;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Chain jumpTrue() {
aoqi@0:             if (tree == null) return Code.mergeChains(trueJumps, code.branch(opcode));
aoqi@0:             // we should proceed further in -Xjcov mode only
aoqi@0:             int startpc = code.curCP();
aoqi@0:             Chain c = Code.mergeChains(trueJumps, code.branch(opcode));
aoqi@0:             code.crt.put(tree, CRTable.CRT_BRANCH_TRUE, startpc, code.curCP());
aoqi@0:             return c;
aoqi@0:         }
aoqi@0: 
aoqi@0:         Chain jumpFalse() {
aoqi@0:             if (tree == null) return Code.mergeChains(falseJumps, code.branch(Code.negate(opcode)));
aoqi@0:             // we should proceed further in -Xjcov mode only
aoqi@0:             int startpc = code.curCP();
aoqi@0:             Chain c = Code.mergeChains(falseJumps, code.branch(Code.negate(opcode)));
aoqi@0:             code.crt.put(tree, CRTable.CRT_BRANCH_FALSE, startpc, code.curCP());
aoqi@0:             return c;
aoqi@0:         }
aoqi@0: 
aoqi@0:         CondItem negate() {
aoqi@0:             CondItem c = new CondItem(Code.negate(opcode), falseJumps, trueJumps);
aoqi@0:             c.tree = tree;
aoqi@0:             return c;
aoqi@0:         }
aoqi@0: 
aoqi@0:         int width() {
aoqi@0:             // a CondItem doesn't have a size on the stack per se.
aoqi@0:             throw new AssertionError();
aoqi@0:         }
aoqi@0: 
aoqi@0:         boolean isTrue() {
aoqi@0:             return falseJumps == null && opcode == goto_;
aoqi@0:         }
aoqi@0: 
aoqi@0:         boolean isFalse() {
aoqi@0:             return trueJumps == null && opcode == dontgoto;
aoqi@0:         }
aoqi@0: 
aoqi@0:         public String toString() {
aoqi@0:             return "cond(" + Code.mnem(opcode) + ")";
aoqi@0:         }
aoqi@0:     }
aoqi@0: }