1 /*
2 * Copyright (c) 2009, 2015, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package jdk.vm.ci.meta;
24
25 import java.lang.annotation.*;
26 import java.net.*;
27
28 import jdk.vm.ci.meta.Assumptions.*;
29
30 /**
31 * Represents a resolved Java type. Types include primitives, objects, {@code void}, and arrays
32 * thereof. Types, like fields and methods, are resolved through {@link ConstantPool constant pools}
33 * .
34 */
35 public interface ResolvedJavaType extends JavaType, ModifiersProvider {
36 /**
37 * Gets the runtime representation of the Java class object of this type.
38 */
39 JavaConstant getJavaClass();
40
41 /**
42 * Gets the runtime representation of the "hub" of this type--that is, the closest part of the
43 * type representation which is typically stored in the object header.
44 */
45 Constant getObjectHub();
46
47 /**
48 * Checks whether this type has a finalizer method.
49 *
50 * @return {@code true} if this class has a finalizer
51 */
52 boolean hasFinalizer();
53
54 /**
55 * Checks whether this type has any finalizable subclasses so far. Any decisions based on this
56 * information require the registration of a dependency, since this information may change.
57 *
58 * @return {@code true} if this class has any subclasses with finalizers
59 */
60 AssumptionResult<Boolean> hasFinalizableSubclass();
61
62 /**
63 * Checks whether this type is an interface.
64 *
65 * @return {@code true} if this type is an interface
66 */
67 boolean isInterface();
68
69 /**
70 * Checks whether this type is an instance class.
71 *
72 * @return {@code true} if this type is an instance class
73 */
74 boolean isInstanceClass();
75
76 /**
77 * Checks whether this type is an array class.
78 *
79 * @return {@code true} if this type is an array class
80 */
81 boolean isArray();
82
83 /**
84 * Checks whether this type is primitive.
85 *
86 * @return {@code true} if this type is primitive
87 */
88 boolean isPrimitive();
89
90 /**
91 * {@inheritDoc}
92 * <p>
93 * Only the flags specified in the JVM specification will be included in the returned mask. This
94 * method is identical to {@link Class#getModifiers()} in terms of the value return for this
95 * type.
96 */
97 int getModifiers();
98
99 /*
100 * The setting of the final bit for types is a bit confusing since arrays are marked as final.
101 * This method provides a semantically equivalent test that appropriate for types.
102 */
103 default boolean isLeaf() {
104 return getElementalType().isFinalFlagSet();
105 }
106
107 /**
108 * Checks whether this type is initialized. If a type is initialized it implies that it was
109 * {@link #isLinked() linked} and that the static initializer has run.
110 *
111 * @return {@code true} if this type is initialized
112 */
113 boolean isInitialized();
114
115 /**
116 * Initializes this type.
117 */
118 void initialize();
119
120 /**
121 * Checks whether this type is linked and verified. When a type is linked the static initializer
122 * has not necessarily run. An {@link #isInitialized() initialized} type is always linked.
123 *
124 * @return {@code true} if this type is linked
125 */
126 boolean isLinked();
127
128 /**
129 * Determines if this type is either the same as, or is a superclass or superinterface of, the
130 * type represented by the specified parameter. This method is identical to
131 * {@link Class#isAssignableFrom(Class)} in terms of the value return for this type.
132 */
133 boolean isAssignableFrom(ResolvedJavaType other);
134
135 /**
136 * Returns true if this type is exactly the type {@link java.lang.Object}.
137 */
138 default boolean isJavaLangObject() {
139 // Removed assertion due to https://bugs.eclipse.org/bugs/show_bug.cgi?id=434442
140 return getSuperclass() == null && !isInterface() && getJavaKind() == JavaKind.Object;
141 }
142
143 /**
144 * Checks whether the specified object is an instance of this type.
145 *
146 * @param obj the object to test
147 * @return {@code true} if the object is an instance of this type
148 */
149 boolean isInstance(JavaConstant obj);
150
151 /**
152 * Returns this type if it is an exact type otherwise returns null. This type is exact if it is
153 * void, primitive, final, or an array of a final or primitive type.
154 *
155 * @return this type if it is exact; {@code null} otherwise
156 */
157 ResolvedJavaType asExactType();
158
159 /**
160 * Gets the super class of this type. If this type represents either the {@code Object} class,
161 * an interface, a primitive type, or void, then null is returned. If this object represents an
162 * array class then the type object representing the {@code Object} class is returned.
163 */
164 ResolvedJavaType getSuperclass();
165
166 /**
167 * Gets the interfaces implemented or extended by this type. This method is analogous to
168 * {@link Class#getInterfaces()} and as such, only returns the interfaces directly implemented
169 * or extended by this type.
170 */
171 ResolvedJavaType[] getInterfaces();
172
173 /**
174 * Gets the single implementor of this type. Calling this method on a non-interface type causes
175 * an exception.
176 * <p>
177 * If the compiler uses the result of this method for its compilation, the usage must be guarded
178 * because the verifier can not guarantee that the assigned type really implements this
179 * interface. Additionally, class loading can invalidate the result of this method.
180 *
181 * @return {@code null} if there is no implementor, the implementor if there is only one, or
182 * {@code this} if there are more than one.
183 */
184 ResolvedJavaType getSingleImplementor();
185
186 /**
187 * Walks the class hierarchy upwards and returns the least common class that is a superclass of
188 * both the current and the given type.
189 *
190 * @return the least common type that is a super type of both the current and the given type, or
191 * {@code null} if primitive types are involved.
192 */
193 ResolvedJavaType findLeastCommonAncestor(ResolvedJavaType otherType);
194
195 /**
196 * Attempts to get a leaf concrete subclass of this type.
197 * <p>
198 * For an {@linkplain #isArray() array} type A, the leaf concrete subclass is A if the
199 * {@linkplain #getElementalType() elemental} type of A is final (which includes primitive
200 * types). Otherwise {@code null} is returned for A.
201 * <p>
202 * For a non-array type T, the result is the leaf concrete type in the current hierarchy of T.
203 * <p>
204 * A runtime may decide not to manage or walk a large hierarchy and so the result is
205 * conservative. That is, a non-null result is guaranteed to be the leaf concrete class in T's
206 * hierarchy <b>at the current point in time</b> but a null result does not necessarily imply
207 * that there is no leaf concrete class in T's hierarchy.
208 * <p>
209 * If the compiler uses the result of this method for its compilation, it must register the
210 * {@link AssumptionResult} in its {@link Assumptions} because dynamic class loading can
211 * invalidate the result of this method.
212 *
213 * @return an {@link AssumptionResult} containing the leaf concrete subclass for this type as
214 * described above
215 */
216 AssumptionResult<ResolvedJavaType> findLeafConcreteSubtype();
217
218 ResolvedJavaType getComponentType();
219
220 default ResolvedJavaType getElementalType() {
221 ResolvedJavaType t = this;
222 while (t.isArray()) {
223 t = t.getComponentType();
224 }
225 return t;
226 }
227
228 ResolvedJavaType getArrayClass();
229
230 /**
231 * Resolves the method implementation for virtual dispatches on objects of this dynamic type.
232 * This resolution process only searches "up" the class hierarchy of this type.
233 *
234 * @param method the method to select the implementation of
235 * @param callerType the caller or context type used to perform access checks
236 * @return the link-time resolved method (might be abstract) or {@code null} if it can not be
237 * linked
238 */
239 ResolvedJavaMethod resolveMethod(ResolvedJavaMethod method, ResolvedJavaType callerType);
240
241 /**
242 * Resolves the method implementation for virtual dispatches on objects of this dynamic type.
243 * This resolution process only searches "up" the class hierarchy of this type. A broader search
244 * that also walks "down" the hierarchy is implemented by
245 * {@link #findUniqueConcreteMethod(ResolvedJavaMethod)}.
246 *
247 * @param method the method to select the implementation of
248 * @param callerType the caller or context type used to perform access checks
249 * @return the concrete method that would be selected at runtime, or {@code null} if there is no
250 * concrete implementation of {@code method} in this type or any of its superclasses
251 */
252 ResolvedJavaMethod resolveConcreteMethod(ResolvedJavaMethod method, ResolvedJavaType callerType);
253
254 /**
255 * Given a {@link ResolvedJavaMethod} A, returns a concrete {@link ResolvedJavaMethod} B that is
256 * the only possible unique target for a virtual call on A(). Returns {@code null} if either no
257 * such concrete method or more than one such method exists. Returns the method A if A is a
258 * concrete method that is not overridden.
259 * <p>
260 * If the compiler uses the result of this method for its compilation, it must register an
261 * assumption because dynamic class loading can invalidate the result of this method.
262 *
263 * @param method the method A for which a unique concrete target is searched
264 * @return the unique concrete target or {@code null} if no such target exists or assumptions
265 * are not supported by this runtime
266 */
267 AssumptionResult<ResolvedJavaMethod> findUniqueConcreteMethod(ResolvedJavaMethod method);
268
269 /**
270 * Returns the instance fields of this class, including
271 * {@linkplain ResolvedJavaField#isInternal() internal} fields. A zero-length array is returned
272 * for array and primitive types. The order of fields returned by this method is stable. That
273 * is, for a single JVM execution the same order is returned each time this method is called. It
274 * is also the "natural" order, which means that the JVM would expect the fields in this order
275 * if no specific order is given.
276 *
277 * @param includeSuperclasses if true, then instance fields for the complete hierarchy of this
278 * type are included in the result
279 * @return an array of instance fields
280 */
281 ResolvedJavaField[] getInstanceFields(boolean includeSuperclasses);
282
283 /**
284 * Returns the static fields of this class, including
285 * {@linkplain ResolvedJavaField#isInternal() internal} fields. A zero-length array is returned
286 * for array and primitive types. The order of fields returned by this method is stable. That
287 * is, for a single JVM execution the same order is returned each time this method is called.
288 */
289 ResolvedJavaField[] getStaticFields();
290
291 /**
292 * Returns all annotations of this class. If no annotations are present, an array of length 0 is
293 * returned.
294 */
295 Annotation[] getAnnotations();
296
297 /**
298 * Returns the annotation for the specified type of this class, if such an annotation is
299 * present.
300 *
301 * @param annotationClass the Class object corresponding to the annotation type
302 * @return this element's annotation for the specified annotation type if present on this class,
303 * else {@code null}
304 */
305 <T extends Annotation> T getAnnotation(Class<T> annotationClass);
306
307 /**
308 * Returns the instance field of this class (or one of its super classes) at the given offset,
309 * or {@code null} if there is no such field.
310 *
311 * @param offset the offset of the field to look for
312 * @return the field with the given offset, or {@code null} if there is no such field.
313 */
314 ResolvedJavaField findInstanceFieldWithOffset(long offset, JavaKind expectedKind);
315
316 /**
317 * Returns name of source file of this type.
318 */
319 String getSourceFileName();
320
321 /**
322 * Returns the class file path - if available - of this type, or {@code null}.
323 */
324 URL getClassFilePath();
325
326 /**
327 * Returns {@code true} if the type is a local type.
328 */
329 boolean isLocal();
330
331 /**
332 * Returns {@code true} if the type is a member type.
333 */
334 boolean isMember();
335
336 /**
337 * Returns the enclosing type of this type, if it exists, or {@code null}.
338 */
339 ResolvedJavaType getEnclosingType();
340
341 /**
342 * Returns an array reflecting all the constructors declared by this type. This method is
343 * similar to {@link Class#getDeclaredConstructors()} in terms of returned constructors.
344 */
345 ResolvedJavaMethod[] getDeclaredConstructors();
346
347 /**
348 * Returns an array reflecting all the methods declared by this type. This method is similar to
349 * {@link Class#getDeclaredMethods()} in terms of returned methods.
350 */
351 ResolvedJavaMethod[] getDeclaredMethods();
352
353 /**
354 * Returns the {@code <clinit>} method for this class if there is one.
355 */
356 ResolvedJavaMethod getClassInitializer();
357
358 /**
359 * Returns true if this type represents an interface and it should be trusted even in places
360 * where the JVM verifier would not give any guarantees other than {@link Object}.
361 */
362 boolean isTrustedInterfaceType();
363
364 default ResolvedJavaMethod findMethod(String name, Signature signature) {
365 for (ResolvedJavaMethod method : getDeclaredMethods()) {
366 if (method.getName().equals(name) && method.getSignature().equals(signature)) {
367 return method;
368 }
369 }
370 return null;
371 }
372 }