| /* |
| * Copyright 1999-2007 Sun Microsystems, Inc. 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. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| package com.sun.tools.javac.jvm; |
| |
| import com.sun.tools.javac.util.*; |
| import com.sun.tools.javac.code.*; |
| |
| import com.sun.tools.javac.code.Symbol.*; |
| import com.sun.tools.javac.code.Type.*; |
| import com.sun.tools.javac.jvm.Code.*; |
| import com.sun.tools.javac.tree.JCTree; |
| |
| import static com.sun.tools.javac.code.TypeTags.*; |
| import static com.sun.tools.javac.jvm.ByteCodes.*; |
| |
| /** A helper class for code generation. Items are objects |
| * that stand for addressable entities in the bytecode. Each item |
| * supports a fixed protocol for loading the item on the stack, storing |
| * into it, converting it into a jump condition, and several others. |
| * There are many individual forms of items, such as local, static, |
| * indexed, or instance variables, values on the top of stack, the |
| * special values this or super, etc. Individual items are represented as |
| * inner classes in class Items. |
| * |
| * <p><b>This is NOT part of any API supported by Sun Microsystems. 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.</b> |
| */ |
| public class Items { |
| |
| /** The current constant pool. |
| */ |
| Pool pool; |
| |
| /** The current code buffer. |
| */ |
| Code code; |
| |
| /** The current symbol table. |
| */ |
| Symtab syms; |
| |
| /** Type utilities. */ |
| Types types; |
| |
| /** Items that exist only once (flyweight pattern). |
| */ |
| private final Item voidItem; |
| private final Item thisItem; |
| private final Item superItem; |
| private final Item[] stackItem = new Item[TypeCodeCount]; |
| |
| public Items(Pool pool, Code code, Symtab syms, Types types) { |
| this.code = code; |
| this.pool = pool; |
| this.types = types; |
| voidItem = new Item(VOIDcode) { |
| public String toString() { return "void"; } |
| }; |
| thisItem = new SelfItem(false); |
| superItem = new SelfItem(true); |
| for (int i = 0; i < VOIDcode; i++) stackItem[i] = new StackItem(i); |
| stackItem[VOIDcode] = voidItem; |
| this.syms = syms; |
| } |
| |
| /** Make a void item |
| */ |
| Item makeVoidItem() { |
| return voidItem; |
| } |
| /** Make an item representing `this'. |
| */ |
| Item makeThisItem() { |
| return thisItem; |
| } |
| |
| /** Make an item representing `super'. |
| */ |
| Item makeSuperItem() { |
| return superItem; |
| } |
| |
| /** Make an item representing a value on stack. |
| * @param type The value's type. |
| */ |
| Item makeStackItem(Type type) { |
| return stackItem[Code.typecode(type)]; |
| } |
| |
| /** Make an item representing an indexed expression. |
| * @param type The expression's type. |
| */ |
| Item makeIndexedItem(Type type) { |
| return new IndexedItem(type); |
| } |
| |
| /** Make an item representing a local variable. |
| * @param v The represented variable. |
| */ |
| LocalItem makeLocalItem(VarSymbol v) { |
| return new LocalItem(v.erasure(types), v.adr); |
| } |
| |
| /** Make an item representing a local anonymous variable. |
| * @param type The represented variable's type. |
| * @param reg The represented variable's register. |
| */ |
| private LocalItem makeLocalItem(Type type, int reg) { |
| return new LocalItem(type, reg); |
| } |
| |
| /** Make an item representing a static variable or method. |
| * @param member The represented symbol. |
| */ |
| Item makeStaticItem(Symbol member) { |
| return new StaticItem(member); |
| } |
| |
| /** Make an item representing an instance variable or method. |
| * @param member The represented symbol. |
| * @param nonvirtual Is the reference not virtual? (true for constructors |
| * and private members). |
| */ |
| Item makeMemberItem(Symbol member, boolean nonvirtual) { |
| return new MemberItem(member, nonvirtual); |
| } |
| |
| /** Make an item representing a literal. |
| * @param type The literal's type. |
| * @param value The literal's value. |
| */ |
| Item makeImmediateItem(Type type, Object value) { |
| return new ImmediateItem(type, value); |
| } |
| |
| /** Make an item representing an assignment expression. |
| * @param lhs The item representing the assignment's left hand side. |
| */ |
| Item makeAssignItem(Item lhs) { |
| return new AssignItem(lhs); |
| } |
| |
| /** Make an item representing a conditional or unconditional jump. |
| * @param opcode The jump's opcode. |
| * @param trueJumps A chain encomassing all jumps that can be taken |
| * if the condition evaluates to true. |
| * @param falseJumps A chain encomassing all jumps that can be taken |
| * if the condition evaluates to false. |
| */ |
| CondItem makeCondItem(int opcode, Chain trueJumps, Chain falseJumps) { |
| return new CondItem(opcode, trueJumps, falseJumps); |
| } |
| |
| /** Make an item representing a conditional or unconditional jump. |
| * @param opcode The jump's opcode. |
| */ |
| CondItem makeCondItem(int opcode) { |
| return makeCondItem(opcode, null, null); |
| } |
| |
| /** The base class of all items, which implements default behavior. |
| */ |
| abstract class Item { |
| |
| /** The type code of values represented by this item. |
| */ |
| int typecode; |
| |
| Item(int typecode) { |
| this.typecode = typecode; |
| } |
| |
| /** Generate code to load this item onto stack. |
| */ |
| Item load() { |
| throw new AssertionError(); |
| } |
| |
| /** Generate code to store top of stack into this item. |
| */ |
| void store() { |
| throw new AssertionError("store unsupported: " + this); |
| } |
| |
| /** Generate code to invoke method represented by this item. |
| */ |
| Item invoke() { |
| throw new AssertionError(this); |
| } |
| |
| /** Generate code to use this item twice. |
| */ |
| void duplicate() {} |
| |
| /** Generate code to avoid having to use this item. |
| */ |
| void drop() {} |
| |
| /** Generate code to stash a copy of top of stack - of typecode toscode - |
| * under this item. |
| */ |
| void stash(int toscode) { |
| stackItem[toscode].duplicate(); |
| } |
| |
| /** Generate code to turn item into a testable condition. |
| */ |
| CondItem mkCond() { |
| load(); |
| return makeCondItem(ifne); |
| } |
| |
| /** Generate code to coerce item to given type code. |
| * @param targetcode The type code to coerce to. |
| */ |
| Item coerce(int targetcode) { |
| if (typecode == targetcode) |
| return this; |
| else { |
| load(); |
| int typecode1 = Code.truncate(typecode); |
| int targetcode1 = Code.truncate(targetcode); |
| if (typecode1 != targetcode1) { |
| int offset = targetcode1 > typecode1 ? targetcode1 - 1 |
| : targetcode1; |
| code.emitop0(i2l + typecode1 * 3 + offset); |
| } |
| if (targetcode != targetcode1) { |
| code.emitop0(int2byte + targetcode - BYTEcode); |
| } |
| return stackItem[targetcode]; |
| } |
| } |
| |
| /** Generate code to coerce item to given type. |
| * @param targettype The type to coerce to. |
| */ |
| Item coerce(Type targettype) { |
| return coerce(Code.typecode(targettype)); |
| } |
| |
| /** Return the width of this item on stack as a number of words. |
| */ |
| int width() { |
| return 0; |
| } |
| |
| public abstract String toString(); |
| } |
| |
| /** An item representing a value on stack. |
| */ |
| class StackItem extends Item { |
| |
| StackItem(int typecode) { |
| super(typecode); |
| } |
| |
| Item load() { |
| return this; |
| } |
| |
| void duplicate() { |
| code.emitop0(width() == 2 ? dup2 : dup); |
| } |
| |
| void drop() { |
| code.emitop0(width() == 2 ? pop2 : pop); |
| } |
| |
| void stash(int toscode) { |
| code.emitop0( |
| (width() == 2 ? dup_x2 : dup_x1) + 3 * (Code.width(toscode) - 1)); |
| } |
| |
| int width() { |
| return Code.width(typecode); |
| } |
| |
| public String toString() { |
| return "stack(" + typecodeNames[typecode] + ")"; |
| } |
| } |
| |
| /** An item representing an indexed expression. |
| */ |
| class IndexedItem extends Item { |
| |
| IndexedItem(Type type) { |
| super(Code.typecode(type)); |
| } |
| |
| Item load() { |
| code.emitop0(iaload + typecode); |
| return stackItem[typecode]; |
| } |
| |
| void store() { |
| code.emitop0(iastore + typecode); |
| } |
| |
| void duplicate() { |
| code.emitop0(dup2); |
| } |
| |
| void drop() { |
| code.emitop0(pop2); |
| } |
| |
| void stash(int toscode) { |
| code.emitop0(dup_x2 + 3 * (Code.width(toscode) - 1)); |
| } |
| |
| int width() { |
| return 2; |
| } |
| |
| public String toString() { |
| return "indexed(" + ByteCodes.typecodeNames[typecode] + ")"; |
| } |
| } |
| |
| /** An item representing `this' or `super'. |
| */ |
| class SelfItem extends Item { |
| |
| /** Flag which determines whether this item represents `this' or `super'. |
| */ |
| boolean isSuper; |
| |
| SelfItem(boolean isSuper) { |
| super(OBJECTcode); |
| this.isSuper = isSuper; |
| } |
| |
| Item load() { |
| code.emitop0(aload_0); |
| return stackItem[typecode]; |
| } |
| |
| public String toString() { |
| return isSuper ? "super" : "this"; |
| } |
| } |
| |
| /** An item representing a local variable. |
| */ |
| class LocalItem extends Item { |
| |
| /** The variable's register. |
| */ |
| int reg; |
| |
| /** The variable's type. |
| */ |
| Type type; |
| |
| LocalItem(Type type, int reg) { |
| super(Code.typecode(type)); |
| assert reg >= 0; |
| this.type = type; |
| this.reg = reg; |
| } |
| |
| Item load() { |
| if (reg <= 3) |
| code.emitop0(iload_0 + Code.truncate(typecode) * 4 + reg); |
| else |
| code.emitop1w(iload + Code.truncate(typecode), reg); |
| return stackItem[typecode]; |
| } |
| |
| void store() { |
| if (reg <= 3) |
| code.emitop0(istore_0 + Code.truncate(typecode) * 4 + reg); |
| else |
| code.emitop1w(istore + Code.truncate(typecode), reg); |
| code.setDefined(reg); |
| } |
| |
| void incr(int x) { |
| if (typecode == INTcode && x >= -32768 && x <= 32767) { |
| code.emitop1w(iinc, reg, x); |
| } else { |
| load(); |
| if (x >= 0) { |
| makeImmediateItem(syms.intType, x).load(); |
| code.emitop0(iadd); |
| } else { |
| makeImmediateItem(syms.intType, -x).load(); |
| code.emitop0(isub); |
| } |
| makeStackItem(syms.intType).coerce(typecode); |
| store(); |
| } |
| } |
| |
| public String toString() { |
| return "localItem(type=" + type + "; reg=" + reg + ")"; |
| } |
| } |
| |
| /** An item representing a static variable or method. |
| */ |
| class StaticItem extends Item { |
| |
| /** The represented symbol. |
| */ |
| Symbol member; |
| |
| StaticItem(Symbol member) { |
| super(Code.typecode(member.erasure(types))); |
| this.member = member; |
| } |
| |
| Item load() { |
| code.emitop2(getstatic, pool.put(member)); |
| return stackItem[typecode]; |
| } |
| |
| void store() { |
| code.emitop2(putstatic, pool.put(member)); |
| } |
| |
| Item invoke() { |
| MethodType mtype = (MethodType)member.erasure(types); |
| int argsize = Code.width(mtype.argtypes); |
| int rescode = Code.typecode(mtype.restype); |
| int sdiff = Code.width(rescode) - argsize; |
| code.emitInvokestatic(pool.put(member), mtype); |
| return stackItem[rescode]; |
| } |
| |
| public String toString() { |
| return "static(" + member + ")"; |
| } |
| } |
| |
| /** An item representing an instance variable or method. |
| */ |
| class MemberItem extends Item { |
| |
| /** The represented symbol. |
| */ |
| Symbol member; |
| |
| /** Flag that determines whether or not access is virtual. |
| */ |
| boolean nonvirtual; |
| |
| MemberItem(Symbol member, boolean nonvirtual) { |
| super(Code.typecode(member.erasure(types))); |
| this.member = member; |
| this.nonvirtual = nonvirtual; |
| } |
| |
| Item load() { |
| code.emitop2(getfield, pool.put(member)); |
| return stackItem[typecode]; |
| } |
| |
| void store() { |
| code.emitop2(putfield, pool.put(member)); |
| } |
| |
| Item invoke() { |
| MethodType mtype = (MethodType)member.externalType(types); |
| int rescode = Code.typecode(mtype.restype); |
| if ((member.owner.flags() & Flags.INTERFACE) != 0) { |
| code.emitInvokeinterface(pool.put(member), mtype); |
| } else if (nonvirtual) { |
| code.emitInvokespecial(pool.put(member), mtype); |
| } else { |
| code.emitInvokevirtual(pool.put(member), mtype); |
| } |
| return stackItem[rescode]; |
| } |
| |
| void duplicate() { |
| stackItem[OBJECTcode].duplicate(); |
| } |
| |
| void drop() { |
| stackItem[OBJECTcode].drop(); |
| } |
| |
| void stash(int toscode) { |
| stackItem[OBJECTcode].stash(toscode); |
| } |
| |
| int width() { |
| return 1; |
| } |
| |
| public String toString() { |
| return "member(" + member + (nonvirtual ? " nonvirtual)" : ")"); |
| } |
| } |
| |
| /** An item representing a literal. |
| */ |
| class ImmediateItem extends Item { |
| |
| /** The literal's value. |
| */ |
| Object value; |
| |
| ImmediateItem(Type type, Object value) { |
| super(Code.typecode(type)); |
| this.value = value; |
| } |
| |
| private void ldc() { |
| int idx = pool.put(value); |
| if (typecode == LONGcode || typecode == DOUBLEcode) { |
| code.emitop2(ldc2w, idx); |
| } else if (idx <= 255) { |
| code.emitop1(ldc1, idx); |
| } else { |
| code.emitop2(ldc2, idx); |
| } |
| } |
| |
| Item load() { |
| switch (typecode) { |
| case INTcode: case BYTEcode: case SHORTcode: case CHARcode: |
| int ival = ((Number)value).intValue(); |
| if (-1 <= ival && ival <= 5) |
| code.emitop0(iconst_0 + ival); |
| else if (Byte.MIN_VALUE <= ival && ival <= Byte.MAX_VALUE) |
| code.emitop1(bipush, ival); |
| else if (Short.MIN_VALUE <= ival && ival <= Short.MAX_VALUE) |
| code.emitop2(sipush, ival); |
| else |
| ldc(); |
| break; |
| case LONGcode: |
| long lval = ((Number)value).longValue(); |
| if (lval == 0 || lval == 1) |
| code.emitop0(lconst_0 + (int)lval); |
| else |
| ldc(); |
| break; |
| case FLOATcode: |
| float fval = ((Number)value).floatValue(); |
| if (isPosZero(fval) || fval == 1.0 || fval == 2.0) |
| code.emitop0(fconst_0 + (int)fval); |
| else { |
| ldc(); |
| } |
| break; |
| case DOUBLEcode: |
| double dval = ((Number)value).doubleValue(); |
| if (isPosZero(dval) || dval == 1.0) |
| code.emitop0(dconst_0 + (int)dval); |
| else |
| ldc(); |
| break; |
| case OBJECTcode: |
| ldc(); |
| break; |
| default: |
| assert false; |
| } |
| return stackItem[typecode]; |
| } |
| //where |
| /** Return true iff float number is positive 0. |
| */ |
| private boolean isPosZero(float x) { |
| return x == 0.0f && 1.0f / x > 0.0f; |
| } |
| /** Return true iff double number is positive 0. |
| */ |
| private boolean isPosZero(double x) { |
| return x == 0.0d && 1.0d / x > 0.0d; |
| } |
| |
| CondItem mkCond() { |
| int ival = ((Number)value).intValue(); |
| return makeCondItem(ival != 0 ? goto_ : dontgoto); |
| } |
| |
| Item coerce(int targetcode) { |
| if (typecode == targetcode) { |
| return this; |
| } else { |
| switch (targetcode) { |
| case INTcode: |
| if (Code.truncate(typecode) == INTcode) |
| return this; |
| else |
| return new ImmediateItem( |
| syms.intType, |
| ((Number)value).intValue()); |
| case LONGcode: |
| return new ImmediateItem( |
| syms.longType, |
| ((Number)value).longValue()); |
| case FLOATcode: |
| return new ImmediateItem( |
| syms.floatType, |
| ((Number)value).floatValue()); |
| case DOUBLEcode: |
| return new ImmediateItem( |
| syms.doubleType, |
| ((Number)value).doubleValue()); |
| case BYTEcode: |
| return new ImmediateItem( |
| syms.byteType, |
| (int)(byte)((Number)value).intValue()); |
| case CHARcode: |
| return new ImmediateItem( |
| syms.charType, |
| (int)(char)((Number)value).intValue()); |
| case SHORTcode: |
| return new ImmediateItem( |
| syms.shortType, |
| (int)(short)((Number)value).intValue()); |
| default: |
| return super.coerce(targetcode); |
| } |
| } |
| } |
| |
| public String toString() { |
| return "immediate(" + value + ")"; |
| } |
| } |
| |
| /** An item representing an assignment expressions. |
| */ |
| class AssignItem extends Item { |
| |
| /** The item representing the assignment's left hand side. |
| */ |
| Item lhs; |
| |
| AssignItem(Item lhs) { |
| super(lhs.typecode); |
| this.lhs = lhs; |
| } |
| |
| Item load() { |
| lhs.stash(typecode); |
| lhs.store(); |
| return stackItem[typecode]; |
| } |
| |
| void duplicate() { |
| load().duplicate(); |
| } |
| |
| void drop() { |
| lhs.store(); |
| } |
| |
| void stash(int toscode) { |
| assert false; |
| } |
| |
| int width() { |
| return lhs.width() + Code.width(typecode); |
| } |
| |
| public String toString() { |
| return "assign(lhs = " + lhs + ")"; |
| } |
| } |
| |
| /** An item representing a conditional or unconditional jump. |
| */ |
| class CondItem extends Item { |
| |
| /** A chain encomassing all jumps that can be taken |
| * if the condition evaluates to true. |
| */ |
| Chain trueJumps; |
| |
| /** A chain encomassing all jumps that can be taken |
| * if the condition evaluates to false. |
| */ |
| Chain falseJumps; |
| |
| /** The jump's opcode. |
| */ |
| int opcode; |
| |
| /* |
| * An abstract syntax tree of this item. It is needed |
| * for branch entries in 'CharacterRangeTable' attribute. |
| */ |
| JCTree tree; |
| |
| CondItem(int opcode, Chain truejumps, Chain falsejumps) { |
| super(BYTEcode); |
| this.opcode = opcode; |
| this.trueJumps = truejumps; |
| this.falseJumps = falsejumps; |
| } |
| |
| Item load() { |
| Chain trueChain = null; |
| Chain falseChain = jumpFalse(); |
| if (!isFalse()) { |
| code.resolve(trueJumps); |
| code.emitop0(iconst_1); |
| trueChain = code.branch(goto_); |
| } |
| if (falseChain != null) { |
| code.resolve(falseChain); |
| code.emitop0(iconst_0); |
| } |
| code.resolve(trueChain); |
| return stackItem[typecode]; |
| } |
| |
| void duplicate() { |
| load().duplicate(); |
| } |
| |
| void drop() { |
| load().drop(); |
| } |
| |
| void stash(int toscode) { |
| assert false; |
| } |
| |
| CondItem mkCond() { |
| return this; |
| } |
| |
| Chain jumpTrue() { |
| if (tree == null) return code.mergeChains(trueJumps, code.branch(opcode)); |
| // we should proceed further in -Xjcov mode only |
| int startpc = code.curPc(); |
| Chain c = code.mergeChains(trueJumps, code.branch(opcode)); |
| code.crt.put(tree, CRTable.CRT_BRANCH_TRUE, startpc, code.curPc()); |
| return c; |
| } |
| |
| Chain jumpFalse() { |
| if (tree == null) return code.mergeChains(falseJumps, code.branch(code.negate(opcode))); |
| // we should proceed further in -Xjcov mode only |
| int startpc = code.curPc(); |
| Chain c = code.mergeChains(falseJumps, code.branch(code.negate(opcode))); |
| code.crt.put(tree, CRTable.CRT_BRANCH_FALSE, startpc, code.curPc()); |
| return c; |
| } |
| |
| CondItem negate() { |
| CondItem c = new CondItem(code.negate(opcode), falseJumps, trueJumps); |
| c.tree = tree; |
| return c; |
| } |
| |
| int width() { |
| // a CondItem doesn't have a size on the stack per se. |
| throw new AssertionError(); |
| } |
| |
| boolean isTrue() { |
| return falseJumps == null && opcode == goto_; |
| } |
| |
| boolean isFalse() { |
| return trueJumps == null && opcode == dontgoto; |
| } |
| |
| public String toString() { |
| return "cond(" + Code.mnem(opcode) + ")"; |
| } |
| } |
| } |
