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_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).longValue();
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 }