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.internal.dynalink.CallSiteDescriptor; 36 import jdk.internal.dynalink.linker.GuardedInvocation; 37 import jdk.internal.dynalink.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_NUMBER; 47 48 // These extend the type index constants in JSType 49 private static final int VOID_TYPE_INDEX; 50 private static final int BOOLEAN_TYPE_INDEX; 51 private static final int CHAR_TYPE_INDEX; 52 private static final int LONG_TYPE_INDEX; 53 private static final int FLOAT_TYPE_INDEX; 54 55 static { 56 final MethodHandle INT_DOUBLE = findOwnMH("ensureInt", int.class, double.class, int.class); 57 ENSURE_INT = new MethodHandle[] { 58 null, 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 findOwnMH("ensureInt", int.class, long.class, int.class), 65 INT_DOUBLE.asType(INT_DOUBLE.type().changeParameterType(0, float.class)), 66 }; 67 68 VOID_TYPE_INDEX = ENSURE_INT.length - 5; 69 BOOLEAN_TYPE_INDEX = ENSURE_INT.length - 4; 70 CHAR_TYPE_INDEX = ENSURE_INT.length - 3; 71 LONG_TYPE_INDEX = ENSURE_INT.length - 2; 72 FLOAT_TYPE_INDEX = ENSURE_INT.length - 1; 73 74 ENSURE_NUMBER = new MethodHandle[] { 75 null, 76 null, 77 findOwnMH("ensureNumber", double.class, Object.class, int.class), 78 ENSURE_INT[VOID_TYPE_INDEX].asType(ENSURE_INT[VOID_TYPE_INDEX].type().changeReturnType(double.class)), 79 ENSURE_INT[BOOLEAN_TYPE_INDEX].asType(ENSURE_INT[BOOLEAN_TYPE_INDEX].type().changeReturnType(double.class)), 80 ENSURE_INT[CHAR_TYPE_INDEX].asType(ENSURE_INT[CHAR_TYPE_INDEX].type().changeReturnType(double.class)), 81 findOwnMH("ensureNumber", double.class, long.class, int.class), 82 null 83 }; 84 } 85 86 /** 87 * Given a method handle and an expected return type, perform return value filtering 88 * according to the optimistic type coercion rules 89 * @param mh method handle 90 * @param expectedReturnType expected return type 91 * @param programPoint program point 92 * @return filtered method 93 */ 94 public static MethodHandle filterOptimisticReturnValue(final MethodHandle mh, final Class<?> expectedReturnType, final int programPoint) { 95 if(!isValid(programPoint)) { 96 return mh; 97 } 98 99 final MethodType type = mh.type(); 100 final Class<?> actualReturnType = type.returnType(); 101 if(TypeUtilities.isConvertibleWithoutLoss(actualReturnType, expectedReturnType)) { 102 return mh; 103 } 104 105 final MethodHandle guard = getOptimisticTypeGuard(expectedReturnType, actualReturnType); 106 return guard == null ? mh : MH.filterReturnValue(mh, MH.insertArguments(guard, guard.type().parameterCount() - 1, programPoint)); 107 } 108 109 /** 110 * Given a guarded invocation and a callsite descriptor, perform return value filtering 111 * according to the optimistic type coercion rules, using the return value from the descriptor 112 * @param inv the invocation 113 * @param desc the descriptor 114 * @return filtered invocation 115 */ 116 public static GuardedInvocation filterOptimisticReturnValue(final GuardedInvocation inv, final CallSiteDescriptor desc) { 117 if(!NashornCallSiteDescriptor.isOptimistic(desc)) { 118 return inv; 119 } 120 return inv.replaceMethods(filterOptimisticReturnValue(inv.getInvocation(), desc.getMethodType().returnType(), 121 NashornCallSiteDescriptor.getProgramPoint(desc)), inv.getGuard()); 122 } 123 124 private static MethodHandle getOptimisticTypeGuard(final Class<?> actual, final Class<?> provable) { 125 final MethodHandle guard; 126 final int provableTypeIndex = getProvableTypeIndex(provable); 127 if (actual == int.class) { 128 guard = ENSURE_INT[provableTypeIndex]; 129 } else if (actual == double.class) { 130 guard = ENSURE_NUMBER[provableTypeIndex]; 131 } else { 132 guard = null; 133 assert !actual.isPrimitive() : actual + ", " + provable; 134 } 135 if(guard != null && !(provable.isPrimitive())) { 136 // Make sure filtering a MethodHandle(...)String works with a filter MethodHandle(Object, int)... Note that 137 // if the return type of the method is incompatible with Number, then the guard will always throw an 138 // UnwarrantedOperationException when invoked, but we must link it anyway as we need the guarded function to 139 // successfully execute and return the non-convertible return value that it'll put into the thrown 140 // UnwarrantedOptimismException. 141 return guard.asType(guard.type().changeParameterType(0, provable)); 142 } 143 return guard; 144 } 145 146 private static int getProvableTypeIndex(final Class<?> provable) { 147 final int accTypeIndex = getAccessorTypeIndex(provable); 148 if(accTypeIndex != -1) { 149 return accTypeIndex; 150 } else if(provable == boolean.class) { 151 return BOOLEAN_TYPE_INDEX; 152 } else if(provable == void.class) { 153 return VOID_TYPE_INDEX; 154 } else if(provable == byte.class || provable == short.class) { 155 return 0; // never needs a guard, as it's assignable to int 156 } else if(provable == char.class) { 157 return CHAR_TYPE_INDEX; 158 } else if(provable == long.class) { 159 return LONG_TYPE_INDEX; 160 } else if(provable == float.class) { 161 return FLOAT_TYPE_INDEX; 162 } 163 throw new AssertionError(provable.getName()); 164 } 165 166 //maps staticallyProvableCallSiteType to actualCallSiteType, throws exception if impossible 167 @SuppressWarnings("unused") 168 private static int ensureInt(final long arg, final int programPoint) { 169 if (JSType.isRepresentableAsInt(arg)) { 170 return (int)arg; 171 } 172 throw UnwarrantedOptimismException.createNarrowest(arg, programPoint); 173 } 174 175 @SuppressWarnings("unused") 176 private static int ensureInt(final double arg, final int programPoint) { 177 if (JSType.isStrictlyRepresentableAsInt(arg)) { 178 return (int)arg; 179 } 180 throw new UnwarrantedOptimismException(arg, programPoint, Type.NUMBER); 181 } 182 183 /** 184 * Returns the argument value as an int. If the argument is not a wrapper for a primitive numeric type 185 * with a value that can be exactly represented as an int, throw an {@link UnwarrantedOptimismException}. 186 * This method is only public so that generated script code can use it. See {code CodeGenerator.ENSURE_INT}. 187 * @param arg the original argument. 188 * @param programPoint the program point used in the exception 189 * @return the value of the argument as an int. 190 * @throws UnwarrantedOptimismException if the argument is not a wrapper for a primitive numeric type with 191 * a value that can be exactly represented as an int. 192 */ 193 public static int ensureInt(final Object arg, final int programPoint) { 194 // NOTE: this doesn't delegate to ensureInt(double, int) as in that case if arg were a Long, it would throw a 195 // (potentially imprecise) Double in the UnwarrantedOptimismException. This way, it will put the correct valued 196 // Long into the exception. 197 if (isPrimitiveNumberWrapper(arg)) { 198 final double d = ((Number)arg).doubleValue(); 199 if (JSType.isStrictlyRepresentableAsInt(d)) { 200 return (int)d; 201 } 202 } 203 throw UnwarrantedOptimismException.createNarrowest(arg, programPoint); 204 } 205 206 private static boolean isPrimitiveNumberWrapper(final Object obj) { 207 if (obj == null) { 208 return false; 209 } 210 final Class<?> c = obj.getClass(); 211 return c == Integer.class || c == Double.class || c == Long.class || 212 c == Float.class || c == Short.class || c == Byte.class; 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 @SuppressWarnings("unused") 232 private static double ensureNumber(final long arg, final int programPoint) { 233 if (JSType.isRepresentableAsDouble(arg)) { 234 return (double) arg; 235 } 236 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT); 237 } 238 239 /** 240 * Returns the argument value as a double. If the argument is not a wrapper for a primitive numeric type 241 * that can be represented as double throw an {@link UnwarrantedOptimismException}. 242 * This method is only public so that generated script code can use it. See {code CodeGenerator.ENSURE_NUMBER}. 243 * @param arg the original argument. 244 * @param programPoint the program point used in the exception 245 * @return the value of the argument as a double. 246 * @throws UnwarrantedOptimismException if the argument is not a wrapper for a primitive numeric type. 247 */ 248 public static double ensureNumber(final Object arg, final int programPoint) { 249 if (isPrimitiveNumberWrapper(arg) 250 && (arg.getClass() != Long.class || JSType.isRepresentableAsDouble((Long) arg))) { 251 return ((Number) arg).doubleValue(); 252 } 253 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT); 254 } 255 256 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 257 return MH.findStatic(MethodHandles.lookup(), OptimisticReturnFilters.class, name, MH.type(rtype, types)); 258 } 259 }