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_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
232 @SuppressWarnings("unused")
233 private static double ensureNumber(final long arg, final int programPoint) {
234 if (JSType.isRepresentableAsDouble(arg)) {
235 return (double) arg;
236 }
237 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT);
238 }
239
240 /**
241 * Returns the argument value as a double. If the argument is not a wrapper for a primitive numeric type
242 * that can be represented as double throw an {@link UnwarrantedOptimismException}.
243 * This method is only public so that generated script code can use it. See {code CodeGenerator.ENSURE_NUMBER}.
244 * @param arg the original argument.
245 * @param programPoint the program point used in the exception
246 * @return the value of the argument as a double.
247 * @throws UnwarrantedOptimismException if the argument is not a wrapper for a primitive numeric type.
248 */
249 public static double ensureNumber(final Object arg, final int programPoint) {
250 if (isPrimitiveNumberWrapper(arg)
251 && (arg.getClass() != Long.class || JSType.isRepresentableAsDouble((Long) arg))) {
252 return ((Number) arg).doubleValue();
253 }
254 throw new UnwarrantedOptimismException(arg, programPoint, Type.OBJECT);
255 }
256
257 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
258 return MH.findStatic(MethodHandles.lookup(), OptimisticReturnFilters.class, name, MH.type(rtype, types));
259 }
260 }