1 /*
2 * Copyright (c) 2009, 2016, 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.reflect.AnnotatedElement;
26
27 import jdk.vm.ci.meta.Assumptions.AssumptionResult;
28
29 /**
30 * Represents a resolved Java type. Types include primitives, objects, {@code void}, and arrays
31 * thereof. Types, like fields and methods, are resolved through {@link ConstantPool constant pools}
32 * .
33 */
34 public interface ResolvedJavaType extends JavaType, ModifiersProvider, AnnotatedElement {
35 /**
36 * Checks whether this type has a finalizer method.
37 *
38 * @return {@code true} if this class has a finalizer
39 */
40 boolean hasFinalizer();
41
42 /**
43 * Checks whether this type has any finalizable subclasses so far. Any decisions based on this
44 * information require the registration of a dependency, since this information may change.
45 *
46 * @return {@code true} if this class has any subclasses with finalizers
47 */
48 AssumptionResult<Boolean> hasFinalizableSubclass();
49
50 /**
51 * Checks whether this type is an interface.
52 *
53 * @return {@code true} if this type is an interface
54 */
55 boolean isInterface();
56
57 /**
58 * Checks whether this type is an instance class.
59 *
60 * @return {@code true} if this type is an instance class
61 */
62 boolean isInstanceClass();
63
64 /**
65 * Checks whether this type is primitive.
66 *
67 * @return {@code true} if this type is primitive
68 */
69 boolean isPrimitive();
70
71 /*
72 * The setting of the final bit for types is a bit confusing since arrays are marked as final.
73 * This method provides a semantically equivalent test that appropriate for types.
74 */
75 default boolean isLeaf() {
76 return getElementalType().isFinalFlagSet();
77 }
78
79 /**
80 * Checks whether this type is initialized. If a type is initialized it implies that it was
81 * {@link #isLinked() linked} and that the static initializer has run.
82 *
83 * @return {@code true} if this type is initialized
84 */
85 boolean isInitialized();
86
87 /**
88 * Initializes this type.
89 */
90 void initialize();
91
92 /**
93 * Checks whether this type is linked and verified. When a type is linked the static initializer
94 * has not necessarily run. An {@link #isInitialized() initialized} type is always linked.
95 *
96 * @return {@code true} if this type is linked
97 */
98 boolean isLinked();
99
100 /**
101 * Determines if this type is either the same as, or is a superclass or superinterface of, the
102 * type represented by the specified parameter. This method is identical to
103 * {@link Class#isAssignableFrom(Class)} in terms of the value return for this type.
104 */
105 boolean isAssignableFrom(ResolvedJavaType other);
106
107 /**
108 * Returns the {@link ResolvedJavaType} object representing the host class of this VM anonymous
109 * class (as opposed to the unrelated concept specified by {@link Class#isAnonymousClass()}) or
110 * {@code null} if this object does not represent a VM anonymous class.
111 */
112 ResolvedJavaType getHostClass();
113
114 /**
115 * Returns true if this type is exactly the type {@link java.lang.Object}.
116 */
117 default boolean isJavaLangObject() {
118 // Removed assertion due to https://bugs.eclipse.org/bugs/show_bug.cgi?id=434442
119 return getSuperclass() == null && !isInterface() && getJavaKind() == JavaKind.Object;
120 }
121
122 /**
123 * Checks whether the specified object is an instance of this type.
124 *
125 * @param obj the object to test
126 * @return {@code true} if the object is an instance of this type
127 */
128 boolean isInstance(JavaConstant obj);
129
130 /**
131 * Gets the super class of this type. If this type represents either the {@code Object} class,
132 * an interface, a primitive type, or void, then null is returned. If this object represents an
133 * array class then the type object representing the {@code Object} class is returned.
134 */
135 ResolvedJavaType getSuperclass();
136
137 /**
138 * Gets the interfaces implemented or extended by this type. This method is analogous to
139 * {@link Class#getInterfaces()} and as such, only returns the interfaces directly implemented
140 * or extended by this type.
141 */
142 ResolvedJavaType[] getInterfaces();
143
144 /**
145 * Gets the single implementor of this type. Calling this method on a non-interface type causes
146 * an exception.
147 * <p>
148 * If the compiler uses the result of this method for its compilation, the usage must be guarded
149 * because the verifier can not guarantee that the assigned type really implements this
150 * interface. Additionally, class loading can invalidate the result of this method.
151 *
152 * @return {@code null} if there is no implementor, the implementor if there is only one, or
153 * {@code this} if there are more than one.
154 */
155 ResolvedJavaType getSingleImplementor();
156
157 /**
158 * Walks the class hierarchy upwards and returns the least common class that is a superclass of
159 * both the current and the given type.
160 *
161 * @return the least common type that is a super type of both the current and the given type, or
162 * {@code null} if primitive types are involved.
163 */
164 ResolvedJavaType findLeastCommonAncestor(ResolvedJavaType otherType);
165
166 /**
167 * Attempts to get a leaf concrete subclass of this type.
168 * <p>
169 * For an {@linkplain #isArray() array} type A, the leaf concrete subclass is A if the
170 * {@linkplain #getElementalType() elemental} type of A is final (which includes primitive
171 * types). Otherwise {@code null} is returned for A.
172 * <p>
173 * For a non-array type T, the result is the leaf concrete type in the current hierarchy of T.
174 * <p>
175 * A runtime may decide not to manage or walk a large hierarchy and so the result is
176 * conservative. That is, a non-null result is guaranteed to be the leaf concrete class in T's
177 * hierarchy <b>at the current point in time</b> but a null result does not necessarily imply
178 * that there is no leaf concrete class in T's hierarchy.
179 * <p>
180 * If the compiler uses the result of this method for its compilation, it must register the
181 * {@link AssumptionResult} in its {@link Assumptions} because dynamic class loading can
182 * invalidate the result of this method.
183 *
184 * @return an {@link AssumptionResult} containing the leaf concrete subclass for this type as
185 * described above
186 */
187 AssumptionResult<ResolvedJavaType> findLeafConcreteSubtype();
188
189 ResolvedJavaType getComponentType();
190
191 default ResolvedJavaType getElementalType() {
192 ResolvedJavaType t = this;
193 while (t.isArray()) {
194 t = t.getComponentType();
195 }
196 return t;
197 }
198
199 ResolvedJavaType getArrayClass();
200
201 /**
202 * Resolves the method implementation for virtual dispatches on objects of this dynamic type.
203 * This resolution process only searches "up" the class hierarchy of this type. A broader search
204 * that also walks "down" the hierarchy is implemented by
205 * {@link #findUniqueConcreteMethod(ResolvedJavaMethod)}. For interface types it returns null
206 * since no concrete object can be an interface.
207 *
208 * @param method the method to select the implementation of
209 * @param callerType the caller or context type used to perform access checks
210 * @return the link-time resolved method (might be abstract) or {@code null} if it is either a
211 * signature polymorphic method or can not be linked.
212 */
213 ResolvedJavaMethod resolveMethod(ResolvedJavaMethod method, ResolvedJavaType callerType);
214
215 /**
216 * A convenience wrapper for {@link #resolveMethod(ResolvedJavaMethod, ResolvedJavaType)} that
217 * only returns non-abstract methods.
218 *
219 * @param method the method to select the implementation of
220 * @param callerType the caller or context type used to perform access checks
221 * @return the concrete method that would be selected at runtime, or {@code null} if there is no
222 * concrete implementation of {@code method} in this type or any of its superclasses
223 */
224 default ResolvedJavaMethod resolveConcreteMethod(ResolvedJavaMethod method, ResolvedJavaType callerType) {
225 ResolvedJavaMethod resolvedMethod = resolveMethod(method, callerType);
226 if (resolvedMethod == null || resolvedMethod.isAbstract()) {
227 return null;
228 }
229 return resolvedMethod;
230 }
231
232 /**
233 * Given a {@link ResolvedJavaMethod} A, returns a concrete {@link ResolvedJavaMethod} B that is
234 * the only possible unique target for a virtual call on A(). Returns {@code null} if either no
235 * such concrete method or more than one such method exists. Returns the method A if A is a
236 * concrete method that is not overridden.
237 * <p>
238 * If the compiler uses the result of this method for its compilation, it must register an
239 * assumption because dynamic class loading can invalidate the result of this method.
240 *
241 * @param method the method A for which a unique concrete target is searched
242 * @return the unique concrete target or {@code null} if no such target exists or assumptions
243 * are not supported by this runtime
244 */
245 AssumptionResult<ResolvedJavaMethod> findUniqueConcreteMethod(ResolvedJavaMethod method);
246
247 /**
248 * Returns the instance fields of this class, including
249 * {@linkplain ResolvedJavaField#isInternal() internal} fields. A zero-length array is returned
250 * for array and primitive types. The order of fields returned by this method is stable. That
251 * is, for a single JVM execution the same order is returned each time this method is called. It
252 * is also the "natural" order, which means that the JVM would expect the fields in this order
253 * if no specific order is given.
254 *
255 * @param includeSuperclasses if true, then instance fields for the complete hierarchy of this
256 * type are included in the result
257 * @return an array of instance fields
258 */
259 ResolvedJavaField[] getInstanceFields(boolean includeSuperclasses);
260
261 /**
262 * Returns the static fields of this class, including {@linkplain ResolvedJavaField#isInternal()
263 * internal} fields. A zero-length array is returned for array and primitive types. The order of
264 * fields returned by this method is stable. That is, for a single JVM execution the same order
265 * is returned each time this method is called.
266 */
267 ResolvedJavaField[] getStaticFields();
268
269 /**
270 * Returns the instance field of this class (or one of its super classes) at the given offset,
271 * or {@code null} if there is no such field.
272 *
273 * @param offset the offset of the field to look for
274 * @return the field with the given offset, or {@code null} if there is no such field.
275 */
276 ResolvedJavaField findInstanceFieldWithOffset(long offset, JavaKind expectedKind);
277
278 /**
279 * Returns name of source file of this type.
280 */
281 String getSourceFileName();
282
283 /**
284 * Returns {@code true} if the type is a local type.
285 */
286 boolean isLocal();
287
288 /**
289 * Returns {@code true} if the type is a member type.
290 */
291 boolean isMember();
292
293 /**
294 * Returns the enclosing type of this type, if it exists, or {@code null}.
295 */
296 ResolvedJavaType getEnclosingType();
297
298 /**
299 * Returns an array reflecting all the constructors declared by this type. This method is
300 * similar to {@link Class#getDeclaredConstructors()} in terms of returned constructors.
301 */
302 ResolvedJavaMethod[] getDeclaredConstructors();
303
304 /**
305 * Returns an array reflecting all the methods declared by this type. This method is similar to
306 * {@link Class#getDeclaredMethods()} in terms of returned methods.
307 */
308 ResolvedJavaMethod[] getDeclaredMethods();
309
310 /**
311 * Returns the {@code <clinit>} method for this class if there is one.
312 */
313 ResolvedJavaMethod getClassInitializer();
314
315 default ResolvedJavaMethod findMethod(String name, Signature signature) {
316 for (ResolvedJavaMethod method : getDeclaredMethods()) {
317 if (method.getName().equals(name) && method.getSignature().equals(signature)) {
318 return method;
319 }
320 }
321 return null;
322 }
323
324 /**
325 * Returns true if this type is {@link Cloneable} and can be safely cloned by creating a normal
326 * Java allocation and populating it from the fields returned by
327 * {@link #getInstanceFields(boolean)}. Some types may require special handling by the platform
328 * so they would to go through the normal {@link Object#clone} path.
329 */
330 boolean isCloneableWithAllocation();
331 }