1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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 -> [class, protection domain set]
37 //
38 // Classes are loaded lazily. The default VM class loader is
39 // represented as null.
40
41 // The underlying data structure is an open 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. Note that the protection
53 // domain field of the dictionary entry has not yet been filled in when
54 // the "real" dictionary entry is created.
55 //
56 // Clients of this class who are interested in finding if a class has
57 // been completely loaded -- not classes in the process of being loaded --
58 // can read the dictionary unlocked. This is safe because
59 // - entries are only deleted when the class loader is not alive, when the
60 // entire dictionary is deleted.
61 // - entries must be fully formed before they are available to concurrent
62 // readers (we must ensure write ordering)
63 //
64 // Note that placeholders are deleted at any time, as they are removed
65 // when a class is completely loaded. Therefore, readers as well as writers
66 // of placeholders must hold the SystemDictionary_lock.
67 //
68
69 class BootstrapInfo;
70 class ClassFileStream;
71 class ClassLoadInfo;
72 class Dictionary;
73 class PackageEntry;
74 class GCTimer;
75 class EventClassLoad;
76 class Symbol;
77
78 template <class E> class GrowableArray;
79
80 class SystemDictionary : AllStatic {
81 friend class BootstrapInfo;
82 friend class ClassPrelinker;
83 friend class ClassPreloader;
84 friend class vmClasses;
85 friend class VMStructs;
86
87 public:
88
89 // Returns a class with a given class name and class loader. Loads the
90 // class if needed. If not found a NoClassDefFoundError or a
91 // ClassNotFoundException is thrown, depending on the value on the
92 // throw_error flag. For most uses the throw_error argument should be set
93 // to true.
94
95 static Klass* resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS);
96 // Convenient call for null loader and protection domain.
97 static Klass* resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS) {
98 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
99 }
100
101 // Returns a class with a given class name and class loader.
102 // Loads the class if needed. If not found null is returned.
103 static Klass* resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
104 // Version with null loader and protection domain
105 static Klass* resolve_or_null(Symbol* class_name, TRAPS) {
106 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
107 }
108
109 // Resolve a superclass or superinterface. Called from ClassFileParser,
110 // parse_interfaces, resolve_instance_class_or_null, load_shared_class
111 // "class_name" is the class whose super class or interface is being resolved.
112 static InstanceKlass* resolve_super_or_fail(Symbol* class_name,
113 Symbol* super_name,
114 Handle class_loader,
115 Handle protection_domain,
116 bool is_superclass,
117 TRAPS);
118 private:
119 // Parse the stream to create a hidden class.
120 // Used by jvm_lookup_define_class.
121 static InstanceKlass* resolve_hidden_class_from_stream(ClassFileStream* st,
122 Symbol* class_name,
123 Handle class_loader,
124 const ClassLoadInfo& cl_info,
125 TRAPS);
126
127 // Resolve a class from stream (called by jni_DefineClass and JVM_DefineClass)
128 // This class is added to the SystemDictionary.
129 static InstanceKlass* resolve_class_from_stream(ClassFileStream* st,
130 Symbol* class_name,
131 Handle class_loader,
132 const ClassLoadInfo& cl_info,
133 TRAPS);
134
135 static oop get_system_class_loader_impl(TRAPS);
136 static oop get_platform_class_loader_impl(TRAPS);
137
138 public:
139 // Resolve either a hidden or normal class from a stream of bytes, based on ClassLoadInfo
140 static InstanceKlass* resolve_from_stream(ClassFileStream* st,
141 Symbol* class_name,
142 Handle class_loader,
143 const ClassLoadInfo& cl_info,
144 TRAPS);
145
146 // Lookup an already loaded class. If not found null is returned.
147 static InstanceKlass* find_instance_klass(Thread* current, Symbol* class_name,
148 Handle class_loader, Handle protection_domain);
149
150 // Lookup an already loaded instance or array class.
151 // Do not make any queries to class loaders; consult only the cache.
152 // If not found null is returned.
153 static Klass* find_instance_or_array_klass(Thread* current, Symbol* class_name,
154 Handle class_loader,
155 Handle protection_domain);
156
157 // Lookup an instance or array class that has already been loaded
158 // either into the given class loader, or else into another class
159 // loader that is constrained (via loader constraints) to produce
160 // a consistent class. Do not take protection domains into account.
161 // Do not make any queries to class loaders; consult only the cache.
162 // Return null if the class is not found.
163 //
164 // This function is a strict superset of find_instance_or_array_klass.
165 // This function (the unchecked version) makes a conservative prediction
166 // of the result of the checked version, assuming successful lookup.
167 // If both functions return non-null, they must return the same value.
168 // Also, the unchecked version may sometimes be non-null where the
169 // checked version is null. This can occur in several ways:
170 // 1. No query has yet been made to the class loader.
171 // 2. The class loader was queried, but chose not to delegate.
172 // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain.
173 // 4. Loading was attempted, but there was a linkage error of some sort.
174 // In all of these cases, the loader constraints on this type are
175 // satisfied, and it is safe for classes in the given class loader
176 // to manipulate strongly-typed values of the found class, subject
177 // to local linkage and access checks.
178 static Klass* find_constrained_instance_or_array_klass(Thread* current,
179 Symbol* class_name,
180 Handle class_loader);
181
182 static void classes_do(MetaspaceClosure* it);
183 // Iterate over all methods in all klasses
184
185 static void methods_do(void f(Method*));
186
187 // Garbage collection support
188
189 // Unload (that is, break root links to) all unmarked classes and
190 // loaders. Returns "true" iff something was unloaded.
191 static bool do_unloading(GCTimer* gc_timer);
192
193 // Printing
194 static void print();
195 static void print_on(outputStream* st);
196 static void dump(outputStream* st, bool verbose);
197
198 // Verification
199 static void verify();
200
201 // Initialization
202 static void initialize(TRAPS);
203
204 public:
205 // Returns java system loader
206 static oop java_system_loader();
207
208 // Returns java platform loader
209 static oop java_platform_loader();
210
211 // Compute the java system and platform loaders
212 static void compute_java_loaders(TRAPS);
213
214 // Register a new class loader
215 static ClassLoaderData* register_loader(Handle class_loader, bool create_mirror_cld = false);
216
217 static void set_system_loader(ClassLoaderData *cld);
218 static void set_platform_loader(ClassLoaderData *cld);
219
220 static Symbol* check_signature_loaders(Symbol* signature, Klass* klass_being_linked,
221 Handle loader1, Handle loader2, bool is_method);
222
223 // JSR 292
224 // find a java.lang.invoke.MethodHandle.invoke* method for a given signature
225 // (asks Java to compute it if necessary, except in a compiler thread)
226 static Method* find_method_handle_invoker(Klass* klass,
227 Symbol* name,
228 Symbol* signature,
229 Klass* accessing_klass,
230 Handle *appendix_result,
231 TRAPS);
232 // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic)
233 // (does not ask Java, since this is a low-level intrinsic defined by the JVM)
234 static Method* find_method_handle_intrinsic(vmIntrinsicID iid,
235 Symbol* signature,
236 TRAPS);
237
238 static void get_all_method_handle_intrinsics(GrowableArray<Method*>* methods) NOT_CDS_RETURN;
239 static void restore_archived_method_handle_intrinsics() NOT_CDS_RETURN;
240
241 // compute java_mirror (java.lang.Class instance) for a type ("I", "[[B", "LFoo;", etc.)
242 // Either the accessing_klass or the CL/PD can be non-null, but not both.
243 static Handle find_java_mirror_for_type(Symbol* signature,
244 Klass* accessing_klass,
245 Handle class_loader,
246 Handle protection_domain,
247 SignatureStream::FailureMode failure_mode,
248 TRAPS);
249 static Handle find_java_mirror_for_type(Symbol* signature,
250 Klass* accessing_klass,
251 SignatureStream::FailureMode failure_mode,
252 TRAPS) {
253 // callee will fill in CL/PD from AK, if they are needed
254 return find_java_mirror_for_type(signature, accessing_klass, Handle(), Handle(),
255 failure_mode, THREAD);
256 }
257
258 // find a java.lang.invoke.MethodType object for a given signature
259 // (asks Java to compute it if necessary, except in a compiler thread)
260 static Handle find_method_handle_type(Symbol* signature,
261 Klass* accessing_klass,
262 TRAPS);
263
264 // find a java.lang.Class object for a given signature
265 static Handle find_field_handle_type(Symbol* signature,
266 Klass* accessing_klass,
267 TRAPS);
268
269 // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
270 static Handle link_method_handle_constant(Klass* caller,
271 int ref_kind, //e.g., JVM_REF_invokeVirtual
272 Klass* callee,
273 Symbol* name,
274 Symbol* signature,
275 TRAPS);
276
277 // ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
278 static void invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS);
279
280 // Record the error when the first attempt to resolve a reference from a constant
281 // pool entry to a class fails.
282 static void add_resolution_error(const constantPoolHandle& pool, int which,
283 Symbol* error, const char* message,
284 Symbol* cause = nullptr, const char* cause_msg = nullptr);
285 static void delete_resolution_error(ConstantPool* pool);
286 static Symbol* find_resolution_error(const constantPoolHandle& pool, int which,
287 const char** message,
288 Symbol** cause, const char** cause_msg);
289
290 // Record a nest host resolution/validation error
291 static void add_nest_host_error(const constantPoolHandle& pool, int which,
292 const char* message);
293 static const char* find_nest_host_error(const constantPoolHandle& pool, int which);
294
295 static void preload_class(JavaThread* current, InstanceKlass* k,
296 ClassLoaderData* loader_data) NOT_CDS_RETURN;
297 protected:
298 static InstanceKlass* _well_known_klasses[];
299
300 private:
301 // table of box klasses (int_klass, etc.)
302 static InstanceKlass* _box_klasses[T_VOID+1];
303
304 static OopHandle _java_system_loader;
305 static OopHandle _java_platform_loader;
306
307 private:
308 // Basic loading operations
309 static InstanceKlass* resolve_instance_class_or_null(Symbol* class_name,
310 Handle class_loader,
311 Handle protection_domain, TRAPS);
312 static Klass* resolve_array_class_or_null(Symbol* class_name,
313 Handle class_loader,
314 Handle protection_domain, TRAPS);
315 static void define_instance_class(InstanceKlass* k, Handle class_loader, TRAPS);
316 static InstanceKlass* find_or_define_helper(Symbol* class_name,
317 Handle class_loader,
318 InstanceKlass* k, TRAPS);
319 static InstanceKlass* load_instance_class_impl(Symbol* class_name, Handle class_loader, TRAPS);
320 static InstanceKlass* load_instance_class(Symbol* class_name,
321 Handle class_loader, TRAPS);
322
323 // Class loader constraints
324 static void check_constraints(InstanceKlass* k, ClassLoaderData* loader,
325 bool defining, TRAPS);
326 static void update_dictionary(JavaThread* current, InstanceKlass* k, ClassLoaderData* loader_data);
327
328 static bool is_shared_class_visible(Symbol* class_name, InstanceKlass* ik,
329 PackageEntry* pkg_entry,
330 Handle class_loader);
331 static bool is_shared_class_visible_impl(Symbol* class_name,
332 InstanceKlass* ik,
333 PackageEntry* pkg_entry,
334 Handle class_loader);
335 static bool check_shared_class_super_type(InstanceKlass* klass, InstanceKlass* super,
336 Handle class_loader, Handle protection_domain,
337 bool is_superclass, TRAPS);
338 static bool check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
339 Handle protection_domain, TRAPS);
340 static void restore_archived_method_handle_intrinsics_impl(TRAPS);
341
342 protected:
343 // Used by SystemDictionaryShared
344
345 // Second part of load_shared_class
346 static void load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data) NOT_CDS_RETURN;
347
348 static bool add_loader_constraint(Symbol* name, Klass* klass_being_linked, Handle loader1,
349 Handle loader2);
350 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld);
351 static InstanceKlass* load_shared_lambda_proxy_class(InstanceKlass* ik,
352 Handle class_loader,
353 Handle protection_domain,
354 PackageEntry* pkg_entry,
355 TRAPS);
356 static InstanceKlass* load_shared_class(InstanceKlass* ik,
357 Handle class_loader,
358 Handle protection_domain,
359 const ClassFileStream *cfs,
360 PackageEntry* pkg_entry,
361 TRAPS);
362 static Handle get_loader_lock_or_null(Handle class_loader);
363 static InstanceKlass* find_or_define_instance_class(Symbol* class_name,
364 Handle class_loader,
365 InstanceKlass* k, TRAPS);
366 public:
367 static bool is_system_class_loader(oop class_loader);
368 static bool is_platform_class_loader(oop class_loader);
369 static bool is_boot_class_loader(oop class_loader) { return class_loader == nullptr; }
370 static bool is_builtin_class_loader(oop class_loader) {
371 return is_boot_class_loader(class_loader) ||
372 is_platform_class_loader(class_loader) ||
373 is_system_class_loader(class_loader);
374 }
375 // Returns TRUE if the method is a non-public member of class java.lang.Object.
376 static bool is_nonpublic_Object_method(Method* m);
377
378 // Return Symbol or throw exception if name given is can not be a valid Symbol.
379 static Symbol* class_name_symbol(const char* name, Symbol* exception, TRAPS);
380 };
381
382 #endif // SHARE_CLASSFILE_SYSTEMDICTIONARY_HPP