OptimisticReturnFilters.java revision 953:221a84ef44c0
1/* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package jdk.nashorn.internal.runtime; 27 28import static jdk.nashorn.internal.lookup.Lookup.MH; 29import static jdk.nashorn.internal.runtime.JSType.getAccessorTypeIndex; 30import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid; 31 32import java.lang.invoke.MethodHandle; 33import java.lang.invoke.MethodHandles; 34import java.lang.invoke.MethodType; 35import jdk.internal.dynalink.CallSiteDescriptor; 36import jdk.internal.dynalink.linker.GuardedInvocation; 37import jdk.internal.dynalink.support.TypeUtilities; 38import jdk.nashorn.internal.codegen.types.Type; 39import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor; 40 41/** 42 * Optimistic return value filters 43 */ 44public final class OptimisticReturnFilters { 45 private static final MethodHandle[] ENSURE_INT; 46 private static final MethodHandle[] ENSURE_LONG; 47 private static final MethodHandle[] ENSURE_NUMBER; 48 49 private static final int BOOLEAN_TYPE_INDEX; 50 private static final int CHAR_TYPE_INDEX; 51 private static final int FLOAT_TYPE_INDEX; 52 private static final int VOID_TYPE_INDEX; 53 54 static { 55 final MethodHandle INT_DOUBLE = findOwnMH("ensureInt", int.class, double.class, int.class); 56 ENSURE_INT = new MethodHandle[] { 57 null, 58 findOwnMH("ensureInt", int.class, long.class, int.class), 59 INT_DOUBLE, 60 findOwnMH("ensureInt", int.class, Object.class, int.class), 61 findOwnMH("ensureInt", int.class, int.class), 62 findOwnMH("ensureInt", int.class, boolean.class, int.class), 63 findOwnMH("ensureInt", int.class, char.class, int.class), 64 INT_DOUBLE.asType(INT_DOUBLE.type().changeParameterType(0, float.class)), 65 }; 66 67 VOID_TYPE_INDEX = ENSURE_INT.length - 4; 68 BOOLEAN_TYPE_INDEX = ENSURE_INT.length - 3; 69 CHAR_TYPE_INDEX = ENSURE_INT.length - 2; 70 FLOAT_TYPE_INDEX = ENSURE_INT.length - 1; 71 72 final MethodHandle LONG_DOUBLE = findOwnMH("ensureLong", long.class, double.class, int.class); 73 ENSURE_LONG = new MethodHandle[] { 74 null, 75 null, 76 LONG_DOUBLE, 77 findOwnMH("ensureLong", long.class, Object.class, int.class), 78 ENSURE_INT[VOID_TYPE_INDEX].asType(ENSURE_INT[VOID_TYPE_INDEX].type().changeReturnType(long.class)), 79 ENSURE_INT[BOOLEAN_TYPE_INDEX].asType(ENSURE_INT[BOOLEAN_TYPE_INDEX].type().changeReturnType(long.class)), 80 ENSURE_INT[CHAR_TYPE_INDEX].asType(ENSURE_INT[CHAR_TYPE_INDEX].type().changeReturnType(long.class)), 81 LONG_DOUBLE.asType(LONG_DOUBLE.type().changeParameterType(0, float.class)), 82 }; 83 84 ENSURE_NUMBER = new MethodHandle[] { 85 null, 86 null, 87 null, 88 findOwnMH("ensureNumber", double.class, Object.class, int.class), 89 ENSURE_INT[VOID_TYPE_INDEX].asType(ENSURE_INT[VOID_TYPE_INDEX].type().changeReturnType(double.class)), 90 ENSURE_INT[BOOLEAN_TYPE_INDEX].asType(ENSURE_INT[BOOLEAN_TYPE_INDEX].type().changeReturnType(double.class)), 91 ENSURE_INT[CHAR_TYPE_INDEX].asType(ENSURE_INT[CHAR_TYPE_INDEX].type().changeReturnType(double.class)), 92 null 93 }; 94 } 95 96 /** 97 * Given a method handle and an expected return type, perform return value filtering 98 * according to the optimistic type coercion rules 99 * @param mh method handle 100 * @param expectedReturnType expected return type 101 * @param programPoint program point 102 * @return filtered method 103 */ 104 public static MethodHandle filterOptimisticReturnValue(final MethodHandle mh, final Class<?> expectedReturnType, final int programPoint) { 105 if(!isValid(programPoint)) { 106 return mh; 107 } 108 109 final MethodType type = mh.type(); 110 final Class<?> actualReturnType = type.returnType(); 111 if(TypeUtilities.isConvertibleWithoutLoss(actualReturnType, expectedReturnType)) { 112 return mh; 113 } 114 115 final MethodHandle guard = getOptimisticTypeGuard(expectedReturnType, actualReturnType); 116 return guard == null ? mh : MH.filterReturnValue(mh, MH.insertArguments(guard, guard.type().parameterCount() - 1, programPoint)); 117 } 118 119 /** 120 * Given a guarded invocation and a callsite descriptor, perform return value filtering 121 * according to the optimistic type coercion rules, using the return value from the descriptor 122 * @param inv the invocation 123 * @param desc the descriptor 124 * @return filtered invocation 125 */ 126 public static GuardedInvocation filterOptimisticReturnValue(final GuardedInvocation inv, final CallSiteDescriptor desc) { 127 if(!NashornCallSiteDescriptor.isOptimistic(desc)) { 128 return inv; 129 } 130 return inv.replaceMethods(filterOptimisticReturnValue(inv.getInvocation(), desc.getMethodType().returnType(), 131 NashornCallSiteDescriptor.getProgramPoint(desc)), inv.getGuard()); 132 } 133 134 private static MethodHandle getOptimisticTypeGuard(final Class<?> actual, final Class<?> provable) { 135 final MethodHandle guard; 136 final int provableTypeIndex = getProvableTypeIndex(provable); 137 if (actual == int.class) { 138 guard = ENSURE_INT[provableTypeIndex]; 139 } else if (actual == long.class) { 140 guard = ENSURE_LONG[provableTypeIndex]; 141 } else if (actual == double.class) { 142 guard = ENSURE_NUMBER[provableTypeIndex]; 143 } else { 144 guard = null; 145 assert !actual.isPrimitive() : actual + ", " + provable; 146 } 147 if(guard != null && !(provable.isPrimitive())) { 148 // Make sure filtering a MethodHandle(...)String works with a filter MethodHandle(Object, int)... Note that 149 // if the return type of the method is incompatible with Number, then the guard will always throw an 150 // UnwarrantedOperationException when invoked, but we must link it anyway as we need the guarded function to 151 // successfully execute and return the non-convertible return value that it'll put into the thrown 152 // UnwarrantedOptimismException. 153 return guard.asType(guard.type().changeParameterType(0, provable)); 154 } 155 return guard; 156 } 157 158 private static int getProvableTypeIndex(final Class<?> provable) { 159 final int accTypeIndex = getAccessorTypeIndex(provable); 160 if(accTypeIndex != -1) { 161 return accTypeIndex; 162 } else if(provable == boolean.class) { 163 return BOOLEAN_TYPE_INDEX; 164 } else if(provable == void.class) { 165 return VOID_TYPE_INDEX; 166 } else if(provable == byte.class || provable == short.class) { 167 return 0; // never needs a guard, as it's assignable to int 168 } else if(provable == char.class) { 169 return CHAR_TYPE_INDEX; 170 } else if(provable == float.class) { 171 return FLOAT_TYPE_INDEX; 172 } 173 throw new AssertionError(provable.getName()); 174 } 175 176 //maps staticallyProvableCallSiteType to actualCallSiteType, throws exception if impossible 177 @SuppressWarnings("unused") 178 private static int ensureInt(final long arg, final int programPoint) { 179 if (JSType.isRepresentableAsInt(arg)) { 180 return (int)arg; 181 } 182 throw new UnwarrantedOptimismException(arg, programPoint); 183 } 184 185 @SuppressWarnings("unused") 186 private static int ensureInt(final double arg, final int programPoint) { 187 if (JSType.isRepresentableAsInt(arg) && !JSType.isNegativeZero(arg)) { 188 return (int)arg; 189 } 190 throw new UnwarrantedOptimismException(arg, programPoint); 191 } 192 193 /** 194 * Returns the argument value as an int. If the argument is not a Number object that can be exactly represented as 195 * an int, throw an {@link UnwarrantedOptimismException}.This method is only public so that generated script code 196 * can use it. See {code CodeGenerator.ENSURE_INT}. 197 * @param arg the original argument. 198 * @param programPoint the program point used in the exception 199 * @return the value of the argument as an int. 200 * @throws UnwarrantedOptimismException if the argument is not a Number that can be exactly represented as an int. 201 */ 202 public static int ensureInt(final Object arg, final int programPoint) { 203 // NOTE: this doesn't delegate to ensureInt(double, int) as in that case if arg were a Long, it would throw a 204 // (potentially imprecise) Double in the UnwarrantedOptimismException. This way, it will put the correct valued 205 // Long into the exception. 206 if (arg instanceof Number) { 207 final double d = ((Number)arg).doubleValue(); 208 if (JSType.isRepresentableAsInt(d) && !JSType.isNegativeZero(d)) { 209 return (int)d; 210 } 211 } 212 throw new UnwarrantedOptimismException(arg, programPoint); 213 } 214 215 @SuppressWarnings("unused") 216 private static int ensureInt(final boolean arg, final int programPoint) { 217 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT); 218 } 219 220 @SuppressWarnings("unused") 221 private static int ensureInt(final char arg, final int programPoint) { 222 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT); 223 } 224 225 @SuppressWarnings("unused") 226 private static int ensureInt(final int programPoint) { 227 // Turns a void into UNDEFINED 228 throw new UnwarrantedOptimismException(ScriptRuntime.UNDEFINED, programPoint, Type.OBJECT); 229 } 230 231 private static long ensureLong(final double arg, final int programPoint) { 232 if (JSType.isRepresentableAsLong(arg) && !JSType.isNegativeZero(arg)) { 233 return (long)arg; 234 } 235 throw new UnwarrantedOptimismException(arg, programPoint); 236 } 237 238 /** 239 * Returns the argument value as a long. If the argument is not a Number object that can be exactly represented as 240 * a long, throw an {@link UnwarrantedOptimismException}.This method is only public so that generated script code 241 * can use it. See {code CodeGenerator.ENSURE_LONG}. 242 * @param arg the original argument. 243 * @param programPoint the program point used in the exception 244 * @return the value of the argument as a long. 245 * @throws UnwarrantedOptimismException if the argument is not a Number that can be exactly represented as a long. 246 */ 247 public static long ensureLong(final Object arg, final int programPoint) { 248 if (arg instanceof Long) { 249 // Must check for Long separately, as Long.doubleValue() isn't precise. 250 return ((Long)arg).longValue(); 251 } else if (arg instanceof Number) { 252 return ensureLong(((Number)arg).doubleValue(), programPoint); 253 } 254 throw new UnwarrantedOptimismException(arg, programPoint); 255 } 256 257 /** 258 * Returns the argument value as a double. If the argument is not a Number object, throw an 259 * {@link UnwarrantedOptimismException}.This method is only public so that generated script code can use it. See 260 * {code CodeGenerator.ENSURE_NUMBER}. 261 * @param arg the original argument. 262 * @param programPoint the program point used in the exception 263 * @return the value of the argument as a double. 264 * @throws UnwarrantedOptimismException if the argument is not a Number that can be exactly represented as a long. 265 */ 266 public static double ensureNumber(final Object arg, final int programPoint) { 267 if (arg instanceof Number) { // arg == null -> false 268 return ((Number)arg).doubleValue(); 269 } 270 throw new UnwarrantedOptimismException(arg, programPoint); 271 } 272 273 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 274 return MH.findStatic(MethodHandles.lookup(), OptimisticReturnFilters.class, name, MH.type(rtype, types)); 275 } 276} 277