001/*
002 * Copyright (c) 2009, 2014, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package jdk.internal.jvmci.meta;
024
025import java.lang.annotation.*;
026import java.net.*;
027
028import jdk.internal.jvmci.meta.Assumptions.*;
029
030/**
031 * Represents a resolved Java type. Types include primitives, objects, {@code void}, and arrays
032 * thereof. Types, like fields and methods, are resolved through {@link ConstantPool constant pools}
033 * .
034 */
035public interface ResolvedJavaType extends JavaType, ModifiersProvider {
036
037    /**
038     * Gets the runtime representation of the Java class object of this type.
039     */
040    JavaConstant getJavaClass();
041
042    /**
043     * Gets the runtime representation of the "hub" of this type--that is, the closest part of the
044     * type representation which is typically stored in the object header.
045     */
046    Constant getObjectHub();
047
048    /**
049     * Checks whether this type has a finalizer method.
050     *
051     * @return {@code true} if this class has a finalizer
052     */
053    boolean hasFinalizer();
054
055    /**
056     * Checks whether this type has any finalizable subclasses so far. Any decisions based on this
057     * information require the registration of a dependency, since this information may change.
058     *
059     * @return {@code true} if this class has any subclasses with finalizers
060     */
061    AssumptionResult<Boolean> hasFinalizableSubclass();
062
063    /**
064     * Checks whether this type is an interface.
065     *
066     * @return {@code true} if this type is an interface
067     */
068    boolean isInterface();
069
070    /**
071     * Checks whether this type is an instance class.
072     *
073     * @return {@code true} if this type is an instance class
074     */
075    boolean isInstanceClass();
076
077    /**
078     * Checks whether this type is an array class.
079     *
080     * @return {@code true} if this type is an array class
081     */
082    boolean isArray();
083
084    /**
085     * Checks whether this type is primitive.
086     *
087     * @return {@code true} if this type is primitive
088     */
089    boolean isPrimitive();
090
091    /**
092     * {@inheritDoc}
093     * <p>
094     * Only the flags specified in the JVM specification will be included in the returned mask. This
095     * method is identical to {@link Class#getModifiers()} in terms of the value return for this
096     * type.
097     */
098    int getModifiers();
099
100    /*
101     * The setting of the final bit for types is a bit confusing since arrays are marked as final.
102     * This method provides a semantically equivalent test that appropriate for types.
103     */
104    default boolean isLeaf() {
105        return getElementalType().isFinalFlagSet();
106    }
107
108    /**
109     * Checks whether this type is initialized. If a type is initialized it implies that it was
110     * {@link #isLinked() linked} and that the static initializer has run.
111     *
112     * @return {@code true} if this type is initialized
113     */
114    boolean isInitialized();
115
116    /**
117     * Initializes this type.
118     */
119    void initialize();
120
121    /**
122     * Checks whether this type is linked and verified. When a type is linked the static initializer
123     * has not necessarily run. An {@link #isInitialized() initialized} type is always linked.
124     *
125     * @return {@code true} if this type is linked
126     */
127    boolean isLinked();
128
129    /**
130     * Determines if this type is either the same as, or is a superclass or superinterface of, the
131     * type represented by the specified parameter. This method is identical to
132     * {@link Class#isAssignableFrom(Class)} in terms of the value return for this type.
133     */
134    boolean isAssignableFrom(ResolvedJavaType other);
135
136    /**
137     * Returns true if this type is exactly the type {@link java.lang.Object}.
138     */
139    default boolean isJavaLangObject() {
140        // Removed assertion due to https://bugs.eclipse.org/bugs/show_bug.cgi?id=434442
141        return getSuperclass() == null && !isInterface() && getKind() == Kind.Object;
142    }
143
144    /**
145     * Checks whether the specified object is an instance of this type.
146     *
147     * @param obj the object to test
148     * @return {@code true} if the object is an instance of this type
149     */
150    boolean isInstance(JavaConstant obj);
151
152    /**
153     * Returns this type if it is an exact type otherwise returns null. This type is exact if it is
154     * void, primitive, final, or an array of a final or primitive type.
155     *
156     * @return this type if it is exact; {@code null} otherwise
157     */
158    ResolvedJavaType asExactType();
159
160    /**
161     * Gets the super class of this type. If this type represents either the {@code Object} class,
162     * an interface, a primitive type, or void, then null is returned. If this object represents an
163     * array class then the type object representing the {@code Object} class is returned.
164     */
165    ResolvedJavaType getSuperclass();
166
167    /**
168     * Gets the interfaces implemented or extended by this type. This method is analogous to
169     * {@link Class#getInterfaces()} and as such, only returns the interfaces directly implemented
170     * or extended by this type.
171     */
172    ResolvedJavaType[] getInterfaces();
173
174    /**
175     * Gets the single implementor of this type. Calling this method on a non-interface type causes
176     * an exception.
177     * <p>
178     * If the compiler uses the result of this method for its compilation, the usage must be guarded
179     * because the verifier can not guarantee that the assigned type really implements this
180     * interface. Additionally, class loading can invalidate the result of this method.
181     *
182     * @return {@code null} if there is no implementor, the implementor if there is only one, or
183     *         {@code this} if there are more than one.
184     */
185    ResolvedJavaType getSingleImplementor();
186
187    /**
188     * Walks the class hierarchy upwards and returns the least common class that is a superclass of
189     * both the current and the given type.
190     *
191     * @return the least common type that is a super type of both the current and the given type, or
192     *         {@code null} if primitive types are involved.
193     */
194    ResolvedJavaType findLeastCommonAncestor(ResolvedJavaType otherType);
195
196    /**
197     * Attempts to get a leaf concrete subclass of this type.
198     * <p>
199     * For an {@linkplain #isArray() array} type A, the leaf concrete subclass is A if the
200     * {@linkplain #getElementalType() elemental} type of A is final (which includes primitive
201     * types). Otherwise {@code null} is returned for A.
202     * <p>
203     * For a non-array type T, the result is the leaf concrete type in the current hierarchy of T.
204     * <p>
205     * A runtime may decide not to manage or walk a large hierarchy and so the result is
206     * conservative. That is, a non-null result is guaranteed to be the leaf concrete class in T's
207     * hierarchy <b>at the current point in time</b> but a null result does not necessarily imply
208     * that there is no leaf concrete class in T's hierarchy.
209     * <p>
210     * If the compiler uses the result of this method for its compilation, it must register the
211     * {@link AssumptionResult} in its {@link Assumptions} because dynamic class loading can
212     * invalidate the result of this method.
213     *
214     * @return an {@link AssumptionResult} containing the leaf concrete subclass for this type as
215     *         described above
216     */
217    AssumptionResult<ResolvedJavaType> findLeafConcreteSubtype();
218
219    ResolvedJavaType getComponentType();
220
221    default ResolvedJavaType getElementalType() {
222        ResolvedJavaType t = this;
223        while (t.isArray()) {
224            t = t.getComponentType();
225        }
226        return t;
227    }
228
229    ResolvedJavaType getArrayClass();
230
231    /**
232     * Resolves the method implementation for virtual dispatches on objects of this dynamic type.
233     * This resolution process only searches "up" the class hierarchy of this type.
234     *
235     * @param method the method to select the implementation of
236     * @param callerType the caller or context type used to perform access checks
237     * @return the link-time resolved method (might be abstract) or {@code null} if it can not be
238     *         linked
239     */
240    ResolvedJavaMethod resolveMethod(ResolvedJavaMethod method, ResolvedJavaType callerType);
241
242    /**
243     * Resolves the method implementation for virtual dispatches on objects of this dynamic type.
244     * This resolution process only searches "up" the class hierarchy of this type. A broader search
245     * that also walks "down" the hierarchy is implemented by
246     * {@link #findUniqueConcreteMethod(ResolvedJavaMethod)}.
247     *
248     * @param method the method to select the implementation of
249     * @param callerType the caller or context type used to perform access checks
250     * @return the concrete method that would be selected at runtime, or {@code null} if there is no
251     *         concrete implementation of {@code method} in this type or any of its superclasses
252     */
253    ResolvedJavaMethod resolveConcreteMethod(ResolvedJavaMethod method, ResolvedJavaType callerType);
254
255    /**
256     * Given a {@link ResolvedJavaMethod} A, returns a concrete {@link ResolvedJavaMethod} B that is
257     * the only possible unique target for a virtual call on A(). Returns {@code null} if either no
258     * such concrete method or more than one such method exists. Returns the method A if A is a
259     * concrete method that is not overridden.
260     * <p>
261     * If the compiler uses the result of this method for its compilation, it must register an
262     * assumption because dynamic class loading can invalidate the result of this method.
263     *
264     * @param method the method A for which a unique concrete target is searched
265     * @return the unique concrete target or {@code null} if no such target exists or assumptions
266     *         are not supported by this runtime
267     */
268    AssumptionResult<ResolvedJavaMethod> findUniqueConcreteMethod(ResolvedJavaMethod method);
269
270    /**
271     * Returns the instance fields of this class, including
272     * {@linkplain ResolvedJavaField#isInternal() internal} fields. A zero-length array is returned
273     * for array and primitive types. The order of fields returned by this method is stable. That
274     * is, for a single JVM execution the same order is returned each time this method is called. It
275     * is also the "natural" order, which means that the JVM would expect the fields in this order
276     * if no specific order is given.
277     *
278     * @param includeSuperclasses if true, then instance fields for the complete hierarchy of this
279     *            type are included in the result
280     * @return an array of instance fields
281     */
282    ResolvedJavaField[] getInstanceFields(boolean includeSuperclasses);
283
284    /**
285     * Returns the static fields of this class, including
286     * {@linkplain ResolvedJavaField#isInternal() internal} fields. A zero-length array is returned
287     * for array and primitive types. The order of fields returned by this method is stable. That
288     * is, for a single JVM execution the same order is returned each time this method is called.
289     */
290    ResolvedJavaField[] getStaticFields();
291
292    /**
293     * Returns the annotation for the specified type of this class, if such an annotation is
294     * present.
295     *
296     * @param annotationClass the Class object corresponding to the annotation type
297     * @return this element's annotation for the specified annotation type if present on this class,
298     *         else {@code null}
299     */
300    <T extends Annotation> T getAnnotation(Class<T> annotationClass);
301
302    /**
303     * Returns the instance field of this class (or one of its super classes) at the given offset,
304     * or {@code null} if there is no such field.
305     *
306     * @param offset the offset of the field to look for
307     * @return the field with the given offset, or {@code null} if there is no such field.
308     */
309    ResolvedJavaField findInstanceFieldWithOffset(long offset, Kind expectedKind);
310
311    /**
312     * Returns name of source file of this type.
313     */
314    String getSourceFileName();
315
316    /**
317     * Returns the class file path - if available - of this type, or {@code null}.
318     */
319    URL getClassFilePath();
320
321    /**
322     * Returns {@code true} if the type is a local type.
323     */
324    boolean isLocal();
325
326    /**
327     * Returns {@code true} if the type is a member type.
328     */
329    boolean isMember();
330
331    /**
332     * Returns the enclosing type of this type, if it exists, or {@code null}.
333     */
334    ResolvedJavaType getEnclosingType();
335
336    /**
337     * Returns an array reflecting all the constructors declared by this type. This method is
338     * similar to {@link Class#getDeclaredConstructors()} in terms of returned constructors.
339     */
340    ResolvedJavaMethod[] getDeclaredConstructors();
341
342    /**
343     * Returns an array reflecting all the methods declared by this type. This method is similar to
344     * {@link Class#getDeclaredMethods()} in terms of returned methods.
345     */
346    ResolvedJavaMethod[] getDeclaredMethods();
347
348    /**
349     * Returns the {@code <clinit>} method for this class if there is one.
350     */
351    ResolvedJavaMethod getClassInitializer();
352
353    /**
354     * Returns true if this type represents an interface and it should be trusted even in places
355     * where the JVM verifier would not give any guarantees other than {@link Object}.
356     */
357    boolean isTrustedInterfaceType();
358
359    default ResolvedJavaMethod findMethod(String name, Signature signature) {
360        for (ResolvedJavaMethod method : getDeclaredMethods()) {
361            if (method.getName().equals(name) && method.getSignature().equals(signature)) {
362                return method;
363            }
364        }
365        return null;
366    }
367}