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 26 package jdk.nashorn.internal.runtime; 27 28 import static jdk.nashorn.internal.lookup.Lookup.MH; 29 import static jdk.nashorn.internal.runtime.JSType.getAccessorTypeIndex; 30 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid; 31 32 import java.lang.invoke.MethodHandle; 33 import java.lang.invoke.MethodHandles; 34 import java.lang.invoke.MethodType; 35 import jdk.dynalink.CallSiteDescriptor; 36 import jdk.dynalink.linker.GuardedInvocation; 37 import jdk.dynalink.linker.support.TypeUtilities; 38 import jdk.nashorn.internal.codegen.types.Type; 39 import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor; 40 41 /** 42 * Optimistic return value filters 43 */ 44 public 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.isStrictlyRepresentableAsInt(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 wrapper for a primitive numeric type 195 * with a value that can be exactly represented as an int, throw an {@link UnwarrantedOptimismException}. 196 * This method is only public so that generated script code 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 wrapper for a primitive numeric type with 201 * a value that can be exactly represented as an int. 202 */ 203 public static int ensureInt(final Object arg, final int programPoint) { 204 // NOTE: this doesn't delegate to ensureInt(double, int) as in that case if arg were a Long, it would throw a 205 // (potentially imprecise) Double in the UnwarrantedOptimismException. This way, it will put the correct valued 206 // Long into the exception. 207 if (isPrimitiveNumberWrapper(arg)) { 208 final double d = ((Number)arg).doubleValue(); 209 if (JSType.isStrictlyRepresentableAsInt(d)) { 210 return (int)d; 211 } 212 } 213 throw new UnwarrantedOptimismException(arg, programPoint); 214 } 215 216 private static boolean isPrimitiveNumberWrapper(final Object obj) { 217 if (obj == null) { 218 return false; 219 } 220 final Class<?> c = obj.getClass(); 221 return c == Integer.class || c == Double.class || c == Long.class || 222 c == Float.class || c == Short.class || c == Byte.class; 223 } 224 225 @SuppressWarnings("unused") 226 private static int ensureInt(final boolean arg, final int programPoint) { 227 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT); 228 } 229 230 @SuppressWarnings("unused") 231 private static int ensureInt(final char arg, final int programPoint) { 232 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT); 233 } 234 235 @SuppressWarnings("unused") 236 private static int ensureInt(final int programPoint) { 237 // Turns a void into UNDEFINED 238 throw new UnwarrantedOptimismException(ScriptRuntime.UNDEFINED, programPoint, Type.OBJECT); 239 } 240 241 private static long ensureLong(final double arg, final int programPoint) { 242 if (JSType.isStrictlyRepresentableAsLong(arg)) { 243 return (long)arg; 244 } 245 throw new UnwarrantedOptimismException(arg, programPoint); 246 } 247 248 /** 249 * Returns the argument value as a long. If the argument is not a wrapper for a primitive numeric type 250 * with a value that can be exactly represented as a long, throw an {@link UnwarrantedOptimismException}. 251 * This method is only public so that generated script code can use it. See {code CodeGenerator.ENSURE_LONG}. 252 * @param arg the original argument. 253 * @param programPoint the program point used in the exception 254 * @return the value of the argument as a long. 255 * @throws UnwarrantedOptimismException if the argument is not a wrapper for a primitive numeric type with 256 * a value that can be exactly represented as a long 257 */ 258 public static long ensureLong(final Object arg, final int programPoint) { 259 if (arg != null) { 260 final Class<?> c = arg.getClass(); 261 if (c == Long.class) { 262 // Must check for Long separately, as Long.doubleValue() isn't precise. 263 return ((Long)arg); 264 } else if (c == Integer.class || c == Double.class || c == Float.class || c == Short.class || 265 c == Byte.class) { 266 return ensureLong(((Number)arg).doubleValue(), programPoint); 267 } 268 } 269 throw new UnwarrantedOptimismException(arg, programPoint); 270 } 271 272 /** 273 * Returns the argument value as a double. If the argument is not a a wrapper for a primitive numeric type 274 * throw an {@link UnwarrantedOptimismException}.This method is only public so that generated script code 275 * can use it. See {code CodeGenerator.ENSURE_NUMBER}. 276 * @param arg the original argument. 277 * @param programPoint the program point used in the exception 278 * @return the value of the argument as a double. 279 * @throws UnwarrantedOptimismException if the argument is not a wrapper for a primitive numeric type. 280 */ 281 public static double ensureNumber(final Object arg, final int programPoint) { 282 if (isPrimitiveNumberWrapper(arg)) { 283 return ((Number)arg).doubleValue(); 284 } 285 throw new UnwarrantedOptimismException(arg, programPoint); 286 } 287 288 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 289 return MH.findStatic(MethodHandles.lookup(), OptimisticReturnFilters.class, name, MH.type(rtype, types)); 290 } 291 }