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 */
23package jdk.vm.ci.meta;
24
25import java.lang.reflect.AnnotatedElement;
26
27import 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 */
34public 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}
332