| /* |
| * Copyright 1999-2006 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.comp; |
| |
| import com.sun.tools.javac.code.*; |
| import com.sun.tools.javac.jvm.*; |
| import com.sun.tools.javac.util.*; |
| |
| import com.sun.tools.javac.code.Type.*; |
| |
| import static com.sun.tools.javac.code.TypeTags.*; |
| import static com.sun.tools.javac.jvm.ByteCodes.*; |
| |
| /** Helper class for constant folding, used by the attribution phase. |
| * This class is marked strictfp as mandated by JLS 15.4. |
| * |
| * <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> |
| */ |
| strictfp class ConstFold { |
| protected static final Context.Key<ConstFold> constFoldKey = |
| new Context.Key<ConstFold>(); |
| |
| private Symtab syms; |
| |
| public static ConstFold instance(Context context) { |
| ConstFold instance = context.get(constFoldKey); |
| if (instance == null) |
| instance = new ConstFold(context); |
| return instance; |
| } |
| |
| private ConstFold(Context context) { |
| context.put(constFoldKey, this); |
| |
| syms = Symtab.instance(context); |
| } |
| |
| static Integer minusOne = -1; |
| static Integer zero = 0; |
| static Integer one = 1; |
| |
| /** Convert boolean to integer (true = 1, false = 0). |
| */ |
| private static Integer b2i(boolean b) { |
| return b ? one : zero; |
| } |
| private static int intValue(Object x) { return ((Number)x).intValue(); } |
| private static long longValue(Object x) { return ((Number)x).longValue(); } |
| private static float floatValue(Object x) { return ((Number)x).floatValue(); } |
| private static double doubleValue(Object x) { return ((Number)x).doubleValue(); } |
| |
| /** Fold binary or unary operation, returning constant type reflecting the |
| * operations result. Return null if fold failed due to an |
| * arithmetic exception. |
| * @param opcode The operation's opcode instruction (usually a byte code), |
| * as entered by class Symtab. |
| * @param argtypes The operation's argument types (a list of length 1 or 2). |
| * Argument types are assumed to have non-null constValue's. |
| */ |
| Type fold(int opcode, List<Type> argtypes) { |
| int argCount = argtypes.length(); |
| if (argCount == 1) |
| return fold1(opcode, argtypes.head); |
| else if (argCount == 2) |
| return fold2(opcode, argtypes.head, argtypes.tail.head); |
| else |
| throw new AssertionError(); |
| } |
| |
| /** Fold unary operation. |
| * @param opcode The operation's opcode instruction (usually a byte code), |
| * as entered by class Symtab. |
| * opcode's ifeq to ifge are for postprocessing |
| * xcmp; ifxx pairs of instructions. |
| * @param operand The operation's operand type. |
| * Argument types are assumed to have non-null constValue's. |
| */ |
| Type fold1(int opcode, Type operand) { |
| try { |
| Object od = operand.constValue(); |
| switch (opcode) { |
| case nop: |
| return operand; |
| case ineg: // unary - |
| return syms.intType.constType(-intValue(od)); |
| case ixor: // ~ |
| return syms.intType.constType(~intValue(od)); |
| case bool_not: // ! |
| return syms.booleanType.constType(b2i(intValue(od) == 0)); |
| case ifeq: |
| return syms.booleanType.constType(b2i(intValue(od) == 0)); |
| case ifne: |
| return syms.booleanType.constType(b2i(intValue(od) != 0)); |
| case iflt: |
| return syms.booleanType.constType(b2i(intValue(od) < 0)); |
| case ifgt: |
| return syms.booleanType.constType(b2i(intValue(od) > 0)); |
| case ifle: |
| return syms.booleanType.constType(b2i(intValue(od) <= 0)); |
| case ifge: |
| return syms.booleanType.constType(b2i(intValue(od) >= 0)); |
| |
| case lneg: // unary - |
| return syms.longType.constType(new Long(-longValue(od))); |
| case lxor: // ~ |
| return syms.longType.constType(new Long(~longValue(od))); |
| |
| case fneg: // unary - |
| return syms.floatType.constType(new Float(-floatValue(od))); |
| |
| case dneg: // ~ |
| return syms.doubleType.constType(new Double(-doubleValue(od))); |
| |
| default: |
| return null; |
| } |
| } catch (ArithmeticException e) { |
| return null; |
| } |
| } |
| |
| /** Fold binary operation. |
| * @param opcode The operation's opcode instruction (usually a byte code), |
| * as entered by class Symtab. |
| * opcode's ifeq to ifge are for postprocessing |
| * xcmp; ifxx pairs of instructions. |
| * @param left The type of the operation's left operand. |
| * @param right The type of the operation's right operand. |
| */ |
| Type fold2(int opcode, Type left, Type right) { |
| try { |
| if (opcode > ByteCodes.preMask) { |
| // we are seeing a composite instruction of the form xcmp; ifxx. |
| // In this case fold both instructions separately. |
| Type t1 = fold2(opcode >> ByteCodes.preShift, left, right); |
| return (t1.constValue() == null) ? t1 |
| : fold1(opcode & ByteCodes.preMask, t1); |
| } else { |
| Object l = left.constValue(); |
| Object r = right.constValue(); |
| switch (opcode) { |
| case iadd: |
| return syms.intType.constType(intValue(l) + intValue(r)); |
| case isub: |
| return syms.intType.constType(intValue(l) - intValue(r)); |
| case imul: |
| return syms.intType.constType(intValue(l) * intValue(r)); |
| case idiv: |
| return syms.intType.constType(intValue(l) / intValue(r)); |
| case imod: |
| return syms.intType.constType(intValue(l) % intValue(r)); |
| case iand: |
| return (left.tag == BOOLEAN |
| ? syms.booleanType : syms.intType) |
| .constType(intValue(l) & intValue(r)); |
| case bool_and: |
| return syms.booleanType.constType(b2i((intValue(l) & intValue(r)) != 0)); |
| case ior: |
| return (left.tag == BOOLEAN |
| ? syms.booleanType : syms.intType) |
| .constType(intValue(l) | intValue(r)); |
| case bool_or: |
| return syms.booleanType.constType(b2i((intValue(l) | intValue(r)) != 0)); |
| case ixor: |
| return (left.tag == BOOLEAN |
| ? syms.booleanType : syms.intType) |
| .constType(intValue(l) ^ intValue(r)); |
| case ishl: case ishll: |
| return syms.intType.constType(intValue(l) << intValue(r)); |
| case ishr: case ishrl: |
| return syms.intType.constType(intValue(l) >> intValue(r)); |
| case iushr: case iushrl: |
| return syms.intType.constType(intValue(l) >>> intValue(r)); |
| case if_icmpeq: |
| return syms.booleanType.constType( |
| b2i(intValue(l) == intValue(r))); |
| case if_icmpne: |
| return syms.booleanType.constType( |
| b2i(intValue(l) != intValue(r))); |
| case if_icmplt: |
| return syms.booleanType.constType( |
| b2i(intValue(l) < intValue(r))); |
| case if_icmpgt: |
| return syms.booleanType.constType( |
| b2i(intValue(l) > intValue(r))); |
| case if_icmple: |
| return syms.booleanType.constType( |
| b2i(intValue(l) <= intValue(r))); |
| case if_icmpge: |
| return syms.booleanType.constType( |
| b2i(intValue(l) >= intValue(r))); |
| |
| case ladd: |
| return syms.longType.constType( |
| new Long(longValue(l) + longValue(r))); |
| case lsub: |
| return syms.longType.constType( |
| new Long(longValue(l) - longValue(r))); |
| case lmul: |
| return syms.longType.constType( |
| new Long(longValue(l) * longValue(r))); |
| case ldiv: |
| return syms.longType.constType( |
| new Long(longValue(l) / longValue(r))); |
| case lmod: |
| return syms.longType.constType( |
| new Long(longValue(l) % longValue(r))); |
| case land: |
| return syms.longType.constType( |
| new Long(longValue(l) & longValue(r))); |
| case lor: |
| return syms.longType.constType( |
| new Long(longValue(l) | longValue(r))); |
| case lxor: |
| return syms.longType.constType( |
| new Long(longValue(l) ^ longValue(r))); |
| case lshl: case lshll: |
| return syms.longType.constType( |
| new Long(longValue(l) << intValue(r))); |
| case lshr: case lshrl: |
| return syms.longType.constType( |
| new Long(longValue(l) >> intValue(r))); |
| case lushr: |
| return syms.longType.constType( |
| new Long(longValue(l) >>> intValue(r))); |
| case lcmp: |
| if (longValue(l) < longValue(r)) |
| return syms.intType.constType(minusOne); |
| else if (longValue(l) > longValue(r)) |
| return syms.intType.constType(one); |
| else |
| return syms.intType.constType(zero); |
| case fadd: |
| return syms.floatType.constType( |
| new Float(floatValue(l) + floatValue(r))); |
| case fsub: |
| return syms.floatType.constType( |
| new Float(floatValue(l) - floatValue(r))); |
| case fmul: |
| return syms.floatType.constType( |
| new Float(floatValue(l) * floatValue(r))); |
| case fdiv: |
| return syms.floatType.constType( |
| new Float(floatValue(l) / floatValue(r))); |
| case fmod: |
| return syms.floatType.constType( |
| new Float(floatValue(l) % floatValue(r))); |
| case fcmpg: case fcmpl: |
| if (floatValue(l) < floatValue(r)) |
| return syms.intType.constType(minusOne); |
| else if (floatValue(l) > floatValue(r)) |
| return syms.intType.constType(one); |
| else if (floatValue(l) == floatValue(r)) |
| return syms.intType.constType(zero); |
| else if (opcode == fcmpg) |
| return syms.intType.constType(one); |
| else |
| return syms.intType.constType(minusOne); |
| case dadd: |
| return syms.doubleType.constType( |
| new Double(doubleValue(l) + doubleValue(r))); |
| case dsub: |
| return syms.doubleType.constType( |
| new Double(doubleValue(l) - doubleValue(r))); |
| case dmul: |
| return syms.doubleType.constType( |
| new Double(doubleValue(l) * doubleValue(r))); |
| case ddiv: |
| return syms.doubleType.constType( |
| new Double(doubleValue(l) / doubleValue(r))); |
| case dmod: |
| return syms.doubleType.constType( |
| new Double(doubleValue(l) % doubleValue(r))); |
| case dcmpg: case dcmpl: |
| if (doubleValue(l) < doubleValue(r)) |
| return syms.intType.constType(minusOne); |
| else if (doubleValue(l) > doubleValue(r)) |
| return syms.intType.constType(one); |
| else if (doubleValue(l) == doubleValue(r)) |
| return syms.intType.constType(zero); |
| else if (opcode == dcmpg) |
| return syms.intType.constType(one); |
| else |
| return syms.intType.constType(minusOne); |
| case if_acmpeq: |
| return syms.booleanType.constType(b2i(l.equals(r))); |
| case if_acmpne: |
| return syms.booleanType.constType(b2i(!l.equals(r))); |
| case string_add: |
| return syms.stringType.constType( |
| left.stringValue() + right.stringValue()); |
| default: |
| return null; |
| } |
| } |
| } catch (ArithmeticException e) { |
| return null; |
| } |
| } |
| |
| /** Coerce constant type to target type. |
| * @param etype The source type of the coercion, |
| * which is assumed to be a constant type compatble with |
| * ttype. |
| * @param ttype The target type of the coercion. |
| */ |
| Type coerce(Type etype, Type ttype) { |
| // WAS if (etype.baseType() == ttype.baseType()) |
| if (etype.tsym.type == ttype.tsym.type) |
| return etype; |
| if (etype.tag <= DOUBLE) { |
| Object n = etype.constValue(); |
| switch (ttype.tag) { |
| case BYTE: |
| return syms.byteType.constType(0 + (byte)intValue(n)); |
| case CHAR: |
| return syms.charType.constType(0 + (char)intValue(n)); |
| case SHORT: |
| return syms.shortType.constType(0 + (short)intValue(n)); |
| case INT: |
| return syms.intType.constType(intValue(n)); |
| case LONG: |
| return syms.longType.constType(longValue(n)); |
| case FLOAT: |
| return syms.floatType.constType(floatValue(n)); |
| case DOUBLE: |
| return syms.doubleType.constType(doubleValue(n)); |
| } |
| } |
| return ttype; |
| } |
| } |
