duke@1: /* jjg@1374: * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved. duke@1: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. duke@1: * duke@1: * This code is free software; you can redistribute it and/or modify it duke@1: * under the terms of the GNU General Public License version 2 only, as ohair@554: * published by the Free Software Foundation. Oracle designates this duke@1: * particular file as subject to the "Classpath" exception as provided ohair@554: * by Oracle in the LICENSE file that accompanied this code. duke@1: * duke@1: * This code is distributed in the hope that it will be useful, but WITHOUT duke@1: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or duke@1: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License duke@1: * version 2 for more details (a copy is included in the LICENSE file that duke@1: * accompanied this code). duke@1: * duke@1: * You should have received a copy of the GNU General Public License version duke@1: * 2 along with this work; if not, write to the Free Software Foundation, duke@1: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. duke@1: * ohair@554: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA ohair@554: * or visit www.oracle.com if you need additional information or have any ohair@554: * questions. duke@1: */ duke@1: duke@1: package com.sun.tools.javac.comp; duke@1: duke@1: import com.sun.tools.javac.code.*; duke@1: import com.sun.tools.javac.jvm.*; duke@1: import com.sun.tools.javac.util.*; duke@1: duke@1: import com.sun.tools.javac.code.Type.*; duke@1: jjg@1374: import static com.sun.tools.javac.code.TypeTag.BOOLEAN; jjg@1374: duke@1: import static com.sun.tools.javac.jvm.ByteCodes.*; duke@1: duke@1: /** Helper class for constant folding, used by the attribution phase. duke@1: * This class is marked strictfp as mandated by JLS 15.4. duke@1: * jjg@581: *

This is NOT part of any supported API. jjg@581: * If you write code that depends on this, you do so at your own risk. duke@1: * This code and its internal interfaces are subject to change or duke@1: * deletion without notice. duke@1: */ duke@1: strictfp class ConstFold { duke@1: protected static final Context.Key constFoldKey = duke@1: new Context.Key(); duke@1: duke@1: private Symtab syms; duke@1: duke@1: public static ConstFold instance(Context context) { duke@1: ConstFold instance = context.get(constFoldKey); duke@1: if (instance == null) duke@1: instance = new ConstFold(context); duke@1: return instance; duke@1: } duke@1: duke@1: private ConstFold(Context context) { duke@1: context.put(constFoldKey, this); duke@1: duke@1: syms = Symtab.instance(context); duke@1: } duke@1: vromero@1442: static final Integer minusOne = -1; vromero@1442: static final Integer zero = 0; vromero@1442: static final Integer one = 1; duke@1: duke@1: /** Convert boolean to integer (true = 1, false = 0). duke@1: */ duke@1: private static Integer b2i(boolean b) { duke@1: return b ? one : zero; duke@1: } duke@1: private static int intValue(Object x) { return ((Number)x).intValue(); } duke@1: private static long longValue(Object x) { return ((Number)x).longValue(); } duke@1: private static float floatValue(Object x) { return ((Number)x).floatValue(); } duke@1: private static double doubleValue(Object x) { return ((Number)x).doubleValue(); } duke@1: duke@1: /** Fold binary or unary operation, returning constant type reflecting the duke@1: * operations result. Return null if fold failed due to an duke@1: * arithmetic exception. duke@1: * @param opcode The operation's opcode instruction (usually a byte code), duke@1: * as entered by class Symtab. duke@1: * @param argtypes The operation's argument types (a list of length 1 or 2). duke@1: * Argument types are assumed to have non-null constValue's. duke@1: */ duke@1: Type fold(int opcode, List argtypes) { duke@1: int argCount = argtypes.length(); duke@1: if (argCount == 1) duke@1: return fold1(opcode, argtypes.head); duke@1: else if (argCount == 2) duke@1: return fold2(opcode, argtypes.head, argtypes.tail.head); duke@1: else duke@1: throw new AssertionError(); duke@1: } duke@1: duke@1: /** Fold unary operation. duke@1: * @param opcode The operation's opcode instruction (usually a byte code), duke@1: * as entered by class Symtab. duke@1: * opcode's ifeq to ifge are for postprocessing duke@1: * xcmp; ifxx pairs of instructions. duke@1: * @param operand The operation's operand type. duke@1: * Argument types are assumed to have non-null constValue's. duke@1: */ duke@1: Type fold1(int opcode, Type operand) { duke@1: try { duke@1: Object od = operand.constValue(); duke@1: switch (opcode) { duke@1: case nop: duke@1: return operand; duke@1: case ineg: // unary - duke@1: return syms.intType.constType(-intValue(od)); duke@1: case ixor: // ~ duke@1: return syms.intType.constType(~intValue(od)); duke@1: case bool_not: // ! duke@1: return syms.booleanType.constType(b2i(intValue(od) == 0)); duke@1: case ifeq: duke@1: return syms.booleanType.constType(b2i(intValue(od) == 0)); duke@1: case ifne: duke@1: return syms.booleanType.constType(b2i(intValue(od) != 0)); duke@1: case iflt: duke@1: return syms.booleanType.constType(b2i(intValue(od) < 0)); duke@1: case ifgt: duke@1: return syms.booleanType.constType(b2i(intValue(od) > 0)); duke@1: case ifle: duke@1: return syms.booleanType.constType(b2i(intValue(od) <= 0)); duke@1: case ifge: duke@1: return syms.booleanType.constType(b2i(intValue(od) >= 0)); duke@1: duke@1: case lneg: // unary - duke@1: return syms.longType.constType(new Long(-longValue(od))); duke@1: case lxor: // ~ duke@1: return syms.longType.constType(new Long(~longValue(od))); duke@1: duke@1: case fneg: // unary - duke@1: return syms.floatType.constType(new Float(-floatValue(od))); duke@1: duke@1: case dneg: // ~ duke@1: return syms.doubleType.constType(new Double(-doubleValue(od))); duke@1: duke@1: default: duke@1: return null; duke@1: } duke@1: } catch (ArithmeticException e) { duke@1: return null; duke@1: } duke@1: } duke@1: duke@1: /** Fold binary operation. duke@1: * @param opcode The operation's opcode instruction (usually a byte code), duke@1: * as entered by class Symtab. duke@1: * opcode's ifeq to ifge are for postprocessing duke@1: * xcmp; ifxx pairs of instructions. duke@1: * @param left The type of the operation's left operand. duke@1: * @param right The type of the operation's right operand. duke@1: */ duke@1: Type fold2(int opcode, Type left, Type right) { duke@1: try { duke@1: if (opcode > ByteCodes.preMask) { duke@1: // we are seeing a composite instruction of the form xcmp; ifxx. duke@1: // In this case fold both instructions separately. duke@1: Type t1 = fold2(opcode >> ByteCodes.preShift, left, right); duke@1: return (t1.constValue() == null) ? t1 duke@1: : fold1(opcode & ByteCodes.preMask, t1); duke@1: } else { duke@1: Object l = left.constValue(); duke@1: Object r = right.constValue(); duke@1: switch (opcode) { duke@1: case iadd: duke@1: return syms.intType.constType(intValue(l) + intValue(r)); duke@1: case isub: duke@1: return syms.intType.constType(intValue(l) - intValue(r)); duke@1: case imul: duke@1: return syms.intType.constType(intValue(l) * intValue(r)); duke@1: case idiv: duke@1: return syms.intType.constType(intValue(l) / intValue(r)); duke@1: case imod: duke@1: return syms.intType.constType(intValue(l) % intValue(r)); duke@1: case iand: jjg@1374: return (left.hasTag(BOOLEAN) duke@1: ? syms.booleanType : syms.intType) duke@1: .constType(intValue(l) & intValue(r)); duke@1: case bool_and: duke@1: return syms.booleanType.constType(b2i((intValue(l) & intValue(r)) != 0)); duke@1: case ior: jjg@1374: return (left.hasTag(BOOLEAN) duke@1: ? syms.booleanType : syms.intType) duke@1: .constType(intValue(l) | intValue(r)); duke@1: case bool_or: duke@1: return syms.booleanType.constType(b2i((intValue(l) | intValue(r)) != 0)); duke@1: case ixor: jjg@1374: return (left.hasTag(BOOLEAN) duke@1: ? syms.booleanType : syms.intType) duke@1: .constType(intValue(l) ^ intValue(r)); duke@1: case ishl: case ishll: duke@1: return syms.intType.constType(intValue(l) << intValue(r)); duke@1: case ishr: case ishrl: duke@1: return syms.intType.constType(intValue(l) >> intValue(r)); duke@1: case iushr: case iushrl: duke@1: return syms.intType.constType(intValue(l) >>> intValue(r)); duke@1: case if_icmpeq: duke@1: return syms.booleanType.constType( duke@1: b2i(intValue(l) == intValue(r))); duke@1: case if_icmpne: duke@1: return syms.booleanType.constType( duke@1: b2i(intValue(l) != intValue(r))); duke@1: case if_icmplt: duke@1: return syms.booleanType.constType( duke@1: b2i(intValue(l) < intValue(r))); duke@1: case if_icmpgt: duke@1: return syms.booleanType.constType( duke@1: b2i(intValue(l) > intValue(r))); duke@1: case if_icmple: duke@1: return syms.booleanType.constType( duke@1: b2i(intValue(l) <= intValue(r))); duke@1: case if_icmpge: duke@1: return syms.booleanType.constType( duke@1: b2i(intValue(l) >= intValue(r))); duke@1: duke@1: case ladd: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) + longValue(r))); duke@1: case lsub: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) - longValue(r))); duke@1: case lmul: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) * longValue(r))); duke@1: case ldiv: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) / longValue(r))); duke@1: case lmod: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) % longValue(r))); duke@1: case land: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) & longValue(r))); duke@1: case lor: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) | longValue(r))); duke@1: case lxor: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) ^ longValue(r))); duke@1: case lshl: case lshll: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) << intValue(r))); duke@1: case lshr: case lshrl: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) >> intValue(r))); duke@1: case lushr: duke@1: return syms.longType.constType( duke@1: new Long(longValue(l) >>> intValue(r))); duke@1: case lcmp: duke@1: if (longValue(l) < longValue(r)) duke@1: return syms.intType.constType(minusOne); duke@1: else if (longValue(l) > longValue(r)) duke@1: return syms.intType.constType(one); duke@1: else duke@1: return syms.intType.constType(zero); duke@1: case fadd: duke@1: return syms.floatType.constType( duke@1: new Float(floatValue(l) + floatValue(r))); duke@1: case fsub: duke@1: return syms.floatType.constType( duke@1: new Float(floatValue(l) - floatValue(r))); duke@1: case fmul: duke@1: return syms.floatType.constType( duke@1: new Float(floatValue(l) * floatValue(r))); duke@1: case fdiv: duke@1: return syms.floatType.constType( duke@1: new Float(floatValue(l) / floatValue(r))); duke@1: case fmod: duke@1: return syms.floatType.constType( duke@1: new Float(floatValue(l) % floatValue(r))); duke@1: case fcmpg: case fcmpl: duke@1: if (floatValue(l) < floatValue(r)) duke@1: return syms.intType.constType(minusOne); duke@1: else if (floatValue(l) > floatValue(r)) duke@1: return syms.intType.constType(one); duke@1: else if (floatValue(l) == floatValue(r)) duke@1: return syms.intType.constType(zero); duke@1: else if (opcode == fcmpg) duke@1: return syms.intType.constType(one); duke@1: else duke@1: return syms.intType.constType(minusOne); duke@1: case dadd: duke@1: return syms.doubleType.constType( duke@1: new Double(doubleValue(l) + doubleValue(r))); duke@1: case dsub: duke@1: return syms.doubleType.constType( duke@1: new Double(doubleValue(l) - doubleValue(r))); duke@1: case dmul: duke@1: return syms.doubleType.constType( duke@1: new Double(doubleValue(l) * doubleValue(r))); duke@1: case ddiv: duke@1: return syms.doubleType.constType( duke@1: new Double(doubleValue(l) / doubleValue(r))); duke@1: case dmod: duke@1: return syms.doubleType.constType( duke@1: new Double(doubleValue(l) % doubleValue(r))); duke@1: case dcmpg: case dcmpl: duke@1: if (doubleValue(l) < doubleValue(r)) duke@1: return syms.intType.constType(minusOne); duke@1: else if (doubleValue(l) > doubleValue(r)) duke@1: return syms.intType.constType(one); duke@1: else if (doubleValue(l) == doubleValue(r)) duke@1: return syms.intType.constType(zero); duke@1: else if (opcode == dcmpg) duke@1: return syms.intType.constType(one); duke@1: else duke@1: return syms.intType.constType(minusOne); duke@1: case if_acmpeq: duke@1: return syms.booleanType.constType(b2i(l.equals(r))); duke@1: case if_acmpne: duke@1: return syms.booleanType.constType(b2i(!l.equals(r))); duke@1: case string_add: duke@1: return syms.stringType.constType( duke@1: left.stringValue() + right.stringValue()); duke@1: default: duke@1: return null; duke@1: } duke@1: } duke@1: } catch (ArithmeticException e) { duke@1: return null; duke@1: } duke@1: } duke@1: duke@1: /** Coerce constant type to target type. duke@1: * @param etype The source type of the coercion, jjg@1374: * which is assumed to be a constant type compatible with duke@1: * ttype. duke@1: * @param ttype The target type of the coercion. duke@1: */ duke@1: Type coerce(Type etype, Type ttype) { duke@1: // WAS if (etype.baseType() == ttype.baseType()) duke@1: if (etype.tsym.type == ttype.tsym.type) duke@1: return etype; jjg@1374: if (etype.isNumeric()) { duke@1: Object n = etype.constValue(); jjg@1374: switch (ttype.getTag()) { duke@1: case BYTE: duke@1: return syms.byteType.constType(0 + (byte)intValue(n)); duke@1: case CHAR: duke@1: return syms.charType.constType(0 + (char)intValue(n)); duke@1: case SHORT: duke@1: return syms.shortType.constType(0 + (short)intValue(n)); duke@1: case INT: duke@1: return syms.intType.constType(intValue(n)); duke@1: case LONG: duke@1: return syms.longType.constType(longValue(n)); duke@1: case FLOAT: duke@1: return syms.floatType.constType(floatValue(n)); duke@1: case DOUBLE: duke@1: return syms.doubleType.constType(doubleValue(n)); duke@1: } duke@1: } duke@1: return ttype; duke@1: } duke@1: }