1 /*
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24
25 #ifndef SHARE_CLASSFILE_SYSTEMDICTIONARY_HPP
26 #define SHARE_CLASSFILE_SYSTEMDICTIONARY_HPP
27
28 #include "oops/oopHandle.hpp"
29 #include "runtime/handles.hpp"
30 #include "runtime/signature.hpp"
31 #include "utilities/vmEnums.hpp"
32
33 // The dictionary in each ClassLoaderData stores all loaded classes, either
34 // initiatied by its class loader or defined by its class loader:
35 //
36 // class loader -> ClassLoaderData -> Loaded and initiated loaded classes
37 //
38 // Classes are loaded lazily. The default VM class loader is
39 // represented as null.
40
41 // The underlying data structure is a concurrent hash table (Dictionary) per
42 // ClassLoaderData with a fixed number of buckets. During loading the
43 // class loader object is locked, (for the VM loader a private lock object is used).
44 // The global SystemDictionary_lock is held for all additions into the ClassLoaderData
45 // dictionaries. TODO: fix lock granularity so that class loading can
46 // be done concurrently, but only by different loaders.
47 //
48 // During loading a placeholder (name, loader) is temporarily placed in
49 // a side data structure, and is used to detect ClassCircularityErrors.
50 //
51 // When class loading is finished, a new entry is added to the dictionary
52 // of the class loader and the placeholder is removed.
53 //
54 // Clients of this class who are interested in finding if a class has
55 // been completely loaded -- not classes in the process of being loaded --
56 // can read the dictionary unlocked. This is safe because
57 // - entries are only deleted when the class loader is not alive, when the
58 // entire dictionary is deleted.
59 // - entries must be fully formed before they are available to concurrent
60 // readers (we must ensure write ordering)
61 //
62 // Note that placeholders are deleted at any time, as they are removed
63 // when a class is completely loaded. Therefore, readers as well as writers
64 // of placeholders must hold the SystemDictionary_lock.
65 //
66
67 class BootstrapInfo;
68 class ClassFileStream;
69 class ClassLoadInfo;
70 class Dictionary;
71 class AllFieldStream;
72 class PackageEntry;
73 class GCTimer;
74 class EventClassLoad;
75 class Symbol;
76
77 template <class E> class GrowableArray;
78
79 class SystemDictionary : AllStatic {
80 friend class AOTLinkedClassBulkLoader;
81 friend class BootstrapInfo;
82 friend class LambdaProxyClassDictionary;
83 friend class vmClasses;
84
85 public:
86
87 // Returns a class with a given class name and class loader. Loads the
88 // class if needed. If not found a NoClassDefFoundError or a
89 // ClassNotFoundException is thrown, depending on the value on the
90 // throw_error flag. For most uses the throw_error argument should be set
91 // to true.
92
93 static Klass* resolve_or_fail(Symbol* class_name, Handle class_loader, bool throw_error, TRAPS);
94 // Convenient call for null loader and protection domain.
95 static Klass* resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS) {
96 return resolve_or_fail(class_name, Handle(), throw_error, THREAD);
97 }
98
99 // Returns a class with a given class name and class loader.
100 // Loads the class if needed. If not found null is returned.
101 static Klass* resolve_or_null(Symbol* class_name, Handle class_loader, TRAPS);
102 // Version with null loader and protection domain
103 static Klass* resolve_or_null(Symbol* class_name, TRAPS) {
104 return resolve_or_null(class_name, Handle(), THREAD);
105 }
106
107 static InstanceKlass* resolve_with_circularity_detection(Symbol* class_name,
108 Symbol* next_name,
109 Handle class_loader,
110 bool is_superclass,
111 TRAPS);
112
113 // Resolve a superclass or superinterface. Called from ClassFileParser,
114 // parse_interfaces, resolve_instance_class_or_null, load_shared_class
115 // "class_name" is the class whose super class or interface is being resolved.
116 static InstanceKlass* resolve_with_circularity_detection_or_fail(Symbol* class_name,
117 Symbol* super_name,
118 Handle class_loader,
119 bool is_superclass, TRAPS) {
120 return resolve_with_circularity_detection(class_name, super_name, class_loader, is_superclass, THREAD);
121 }
122
123 private:
124 // Parse the stream to create a hidden class.
125 // Used by jvm_lookup_define_class.
126 static InstanceKlass* resolve_hidden_class_from_stream(ClassFileStream* st,
127 Symbol* class_name,
128 Handle class_loader,
129 const ClassLoadInfo& cl_info,
130 TRAPS);
131
132 // Resolve a class from stream (called by jni_DefineClass and JVM_DefineClass)
133 // This class is added to the SystemDictionary.
134 static InstanceKlass* resolve_class_from_stream(ClassFileStream* st,
135 Symbol* class_name,
136 Handle class_loader,
137 const ClassLoadInfo& cl_info,
138 TRAPS);
139
140 static oop get_system_class_loader_impl(TRAPS);
141 static oop get_platform_class_loader_impl(TRAPS);
142
143 public:
144
145 // Resolve either a hidden or normal class from a stream of bytes, based on ClassLoadInfo
146 static InstanceKlass* resolve_from_stream(ClassFileStream* st,
147 Symbol* class_name,
148 Handle class_loader,
149 const ClassLoadInfo& cl_info,
150 TRAPS);
151
152 // Lookup an already loaded class. If not found null is returned.
153 static InstanceKlass* find_instance_klass(Thread* current, Symbol* class_name,
154 Handle class_loader);
155
156 // Lookup an already loaded instance or array class.
157 // Do not make any queries to class loaders; consult only the cache.
158 // If not found null is returned.
159 static Klass* find_instance_or_array_klass(Thread* current, Symbol* class_name,
160 Handle class_loader);
161
162 // Lookup an instance or array class that has already been loaded
163 // either into the given class loader, or else into another class
164 // loader that is constrained (via loader constraints) to produce
165 // a consistent class. Do not take protection domains into account.
166 // Do not make any queries to class loaders; consult only the cache.
167 // Return null if the class is not found.
168 //
169 // This function is a strict superset of find_instance_or_array_klass.
170 // This function (the unchecked version) makes a conservative prediction
171 // of the result of the checked version, assuming successful lookup.
172 // If both functions return non-null, they must return the same value.
173 // Also, the unchecked version may sometimes be non-null where the
174 // checked version is null. This can occur in several ways:
175 // 1. No query has yet been made to the class loader.
176 // 2. The class loader was queried, but chose not to delegate.
177 // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain.
178 // 4. Loading was attempted, but there was a linkage error of some sort.
179 // In all of these cases, the loader constraints on this type are
180 // satisfied, and it is safe for classes in the given class loader
181 // to manipulate strongly-typed values of the found class, subject
182 // to local linkage and access checks.
183 static Klass* find_constrained_instance_or_array_klass(Thread* current,
184 Symbol* class_name,
185 Handle class_loader);
186
187 static void classes_do(MetaspaceClosure* it);
188 // Iterate over all methods in all klasses
189 // Will not keep metadata alive. See ClassLoaderDataGraph::methods_do.
190 static void methods_do(void f(Method*));
191
192 // Garbage collection support
193
194 // Unload (that is, break root links to) all unmarked classes and
195 // loaders. Returns "true" iff something was unloaded.
196 static bool do_unloading(GCTimer* gc_timer);
197
198 // Printing
199 static void print();
200 static void print_on(outputStream* st);
201 static void dump(outputStream* st, bool verbose);
202
203 // Verification
204 static void verify();
205
206 // Initialization
207 static void initialize(TRAPS);
208
209 public:
210 // Returns java system loader
211 static oop java_system_loader();
212
213 // Returns java platform loader
214 static oop java_platform_loader();
215
216 // Compute the java system and platform loaders
217 static void compute_java_loaders(TRAPS);
218
219 // Register a new class loader
220 static ClassLoaderData* register_loader(Handle class_loader, bool create_mirror_cld = false);
221
222 static void set_system_loader(ClassLoaderData *cld);
223 static void set_platform_loader(ClassLoaderData *cld);
224
225 static Symbol* check_signature_loaders(Symbol* signature, Klass* klass_being_linked,
226 Handle loader1, Handle loader2, bool is_method);
227
228 // JSR 292
229 // find a java.lang.invoke.MethodHandle.invoke* method for a given signature
230 // (asks Java to compute it if necessary, except in a compiler thread)
231 static Method* find_method_handle_invoker(Klass* klass,
232 Symbol* name,
233 Symbol* signature,
234 Klass* accessing_klass,
235 Handle *appendix_result,
236 TRAPS);
237 // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic)
238 // (does not ask Java, since this is a low-level intrinsic defined by the JVM)
239 static Method* find_method_handle_intrinsic(vmIntrinsicID iid,
240 Symbol* signature,
241 TRAPS);
242
243 static void get_all_method_handle_intrinsics(GrowableArray<Method*>* methods) NOT_CDS_RETURN;
244 static void restore_archived_method_handle_intrinsics() NOT_CDS_RETURN;
245
246 // compute java_mirror (java.lang.Class instance) for a type ("I", "[[B", "LFoo;", etc.)
247 static Handle find_java_mirror_for_type(Symbol* signature,
248 Klass* accessing_klass,
249 SignatureStream::FailureMode failure_mode,
250 TRAPS);
251
252 // find a java.lang.invoke.MethodType object for a given signature
253 // (asks Java to compute it if necessary, except in a compiler thread)
254 static Handle find_method_handle_type(Symbol* signature,
255 Klass* accessing_klass,
256 TRAPS);
257
258 // find a java.lang.Class object for a given signature
259 static Handle find_field_handle_type(Symbol* signature,
260 Klass* accessing_klass,
261 TRAPS);
262
263 // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
264 static Handle link_method_handle_constant(Klass* caller,
265 int ref_kind, //e.g., JVM_REF_invokeVirtual
266 Klass* callee,
267 Symbol* name,
268 Symbol* signature,
269 TRAPS);
270
271 // ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
272 static void invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS);
273
274 // Record the error when the first attempt to resolve a reference from a constant
275 // pool entry to a class fails.
276 static void add_resolution_error(const constantPoolHandle& pool, int which,
277 Symbol* error, const char* message,
278 Symbol* cause = nullptr, const char* cause_msg = nullptr);
279 static void delete_resolution_error(ConstantPool* pool);
280 static Symbol* find_resolution_error(const constantPoolHandle& pool, int which,
281 const char** message,
282 Symbol** cause, const char** cause_msg);
283
284 // Record a nest host resolution/validation error
285 static void add_nest_host_error(const constantPoolHandle& pool, int which,
286 const char* message);
287 static const char* find_nest_host_error(const constantPoolHandle& pool, int which);
288
289 static void add_to_initiating_loader(JavaThread* current, InstanceKlass* k,
290 ClassLoaderData* loader_data) NOT_CDS_RETURN;
291
292 static OopHandle _java_system_loader;
293 static OopHandle _java_platform_loader;
294
295 private:
296 // Basic loading operations
297 static InstanceKlass* resolve_instance_class_or_null(Symbol* class_name,
298 Handle class_loader,
299 TRAPS);
300 static Klass* resolve_array_class_or_null(Symbol* class_name,
301 Handle class_loader,
302 TRAPS);
303 static void define_instance_class(InstanceKlass* k, Handle class_loader, TRAPS);
304 static InstanceKlass* find_or_define_helper(Symbol* class_name,
305 Handle class_loader,
306 InstanceKlass* k, TRAPS);
307 static InstanceKlass* load_instance_class_impl(Symbol* class_name, Handle class_loader, TRAPS);
308 static InstanceKlass* load_instance_class(Symbol* class_name,
309 Handle class_loader, TRAPS);
310
311 // Class loader constraints
312 static void check_constraints(InstanceKlass* k, ClassLoaderData* loader,
313 bool defining, TRAPS);
314 static void update_dictionary(JavaThread* current, InstanceKlass* k, ClassLoaderData* loader_data);
315
316 static bool is_shared_class_visible(Symbol* class_name, InstanceKlass* ik,
317 PackageEntry* pkg_entry,
318 Handle class_loader);
319 static bool is_shared_class_visible_impl(Symbol* class_name,
320 InstanceKlass* ik,
321 PackageEntry* pkg_entry,
322 Handle class_loader);
323 static bool check_shared_class_super_type(InstanceKlass* klass, InstanceKlass* super,
324 Handle class_loader,
325 bool is_superclass, TRAPS);
326 static bool check_shared_class_super_types(InstanceKlass* ik, Handle class_loader, TRAPS);
327 // Second part of load_shared_class
328 static void load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data) NOT_CDS_RETURN;
329 static void restore_archived_method_handle_intrinsics_impl(TRAPS) NOT_CDS_RETURN;
330
331 protected:
332 // Used by SystemDictionaryShared and LambdaProxyClassDictionary
333
334 static bool add_loader_constraint(Symbol* name, Klass* klass_being_linked, Handle loader1,
335 Handle loader2);
336 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld);
337 static InstanceKlass* load_shared_class(InstanceKlass* ik,
338 Handle class_loader,
339 Handle protection_domain,
340 const ClassFileStream *cfs,
341 PackageEntry* pkg_entry,
342 TRAPS);
343 static Handle get_loader_lock_or_null(Handle class_loader);
344 static InstanceKlass* find_or_define_instance_class(Symbol* class_name,
345 Handle class_loader,
346 InstanceKlass* k, TRAPS);
347
348 public:
349 static bool is_system_class_loader(oop class_loader);
350 static bool is_platform_class_loader(oop class_loader);
351 static bool is_boot_class_loader(oop class_loader) { return class_loader == nullptr; }
352 static bool is_builtin_class_loader(oop class_loader) {
353 return is_boot_class_loader(class_loader) ||
354 is_platform_class_loader(class_loader) ||
355 is_system_class_loader(class_loader);
356 }
357 // Returns TRUE if the method is a non-public member of class java.lang.Object.
358 static bool is_nonpublic_Object_method(Method* m);
359
360 // Return Symbol or throw exception if name given is can not be a valid Symbol.
361 static Symbol* class_name_symbol(const char* name, Symbol* exception, TRAPS);
362 };
363
364 #endif // SHARE_CLASSFILE_SYSTEMDICTIONARY_HPP