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 AllFieldStream;
74 class PackageEntry;
75 class GCTimer;
76 class EventClassLoad;
77 class Symbol;
78
79 class SystemDictionary : AllStatic {
80 friend class BootstrapInfo;
81 friend class vmClasses;
82 friend class VMStructs;
83
84 public:
85
86 // Returns a class with a given class name and class loader. Loads the
87 // class if needed. If not found a NoClassDefFoundError or a
88 // ClassNotFoundException is thrown, depending on the value on the
89 // throw_error flag. For most uses the throw_error argument should be set
90 // to true.
91
92 static Klass* resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS);
93 // Convenient call for null loader and protection domain.
94 static Klass* resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS) {
95 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
96 }
97
98 // Returns a class with a given class name and class loader.
99 // Loads the class if needed. If not found null is returned.
100 static Klass* resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
101 // Version with null loader and protection domain
102 static Klass* resolve_or_null(Symbol* class_name, TRAPS) {
103 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
104 }
105
106 // Resolve a superclass or superinterface. Called from ClassFileParser,
107 // parse_interfaces, resolve_instance_class_or_null, load_shared_class
108 // "class_name" is the class whose super class or interface is being resolved.
109 static InstanceKlass* resolve_super_or_fail(Symbol* class_name,
110 Symbol* super_name,
111 Handle class_loader,
112 Handle protection_domain,
113 bool is_superclass,
114 TRAPS);
115 private:
116 // Parse the stream to create a hidden class.
117 // Used by jvm_lookup_define_class.
118 static InstanceKlass* resolve_hidden_class_from_stream(ClassFileStream* st,
119 Symbol* class_name,
120 Handle class_loader,
121 const ClassLoadInfo& cl_info,
122 TRAPS);
123
124 // Resolve a class from stream (called by jni_DefineClass and JVM_DefineClass)
125 // This class is added to the SystemDictionary.
126 static InstanceKlass* resolve_class_from_stream(ClassFileStream* st,
127 Symbol* class_name,
128 Handle class_loader,
129 const ClassLoadInfo& cl_info,
130 TRAPS);
131
132 static oop get_system_class_loader_impl(TRAPS);
133 static oop get_platform_class_loader_impl(TRAPS);
134
135 public:
136 static Klass* resolve_inline_type_field_or_fail(Symbol* signature,
137 Handle class_loader,
138 Handle protection_domain,
139 bool throw_error,
140 TRAPS);
141
142 // Resolve either a hidden or normal class from a stream of bytes, based on ClassLoadInfo
143 static InstanceKlass* resolve_from_stream(ClassFileStream* st,
144 Symbol* class_name,
145 Handle class_loader,
146 const ClassLoadInfo& cl_info,
147 TRAPS);
148
149 // Lookup an already loaded class. If not found null is returned.
150 static InstanceKlass* find_instance_klass(Thread* current, Symbol* class_name,
151 Handle class_loader, Handle protection_domain);
152
153 // Lookup an already loaded instance or array class.
154 // Do not make any queries to class loaders; consult only the cache.
155 // If not found null is returned.
156 static Klass* find_instance_or_array_klass(Thread* current, Symbol* class_name,
157 Handle class_loader,
158 Handle protection_domain);
159
160 // Lookup an instance or array class that has already been loaded
161 // either into the given class loader, or else into another class
162 // loader that is constrained (via loader constraints) to produce
163 // a consistent class. Do not take protection domains into account.
164 // Do not make any queries to class loaders; consult only the cache.
165 // Return null if the class is not found.
166 //
167 // This function is a strict superset of find_instance_or_array_klass.
168 // This function (the unchecked version) makes a conservative prediction
169 // of the result of the checked version, assuming successful lookup.
170 // If both functions return non-null, they must return the same value.
171 // Also, the unchecked version may sometimes be non-null where the
172 // checked version is null. This can occur in several ways:
173 // 1. No query has yet been made to the class loader.
174 // 2. The class loader was queried, but chose not to delegate.
175 // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain.
176 // 4. Loading was attempted, but there was a linkage error of some sort.
177 // In all of these cases, the loader constraints on this type are
178 // satisfied, and it is safe for classes in the given class loader
179 // to manipulate strongly-typed values of the found class, subject
180 // to local linkage and access checks.
181 static Klass* find_constrained_instance_or_array_klass(Thread* current,
182 Symbol* class_name,
183 Handle class_loader);
184
185 static void classes_do(MetaspaceClosure* it);
186 // Iterate over all methods in all klasses
187
188 static void methods_do(void f(Method*));
189
190 // Garbage collection support
191
192 // Unload (that is, break root links to) all unmarked classes and
193 // loaders. Returns "true" iff something was unloaded.
194 static bool do_unloading(GCTimer* gc_timer);
195
196 // Printing
197 static void print();
198 static void print_on(outputStream* st);
199 static void dump(outputStream* st, bool verbose);
200
201 // Verification
202 static void verify();
203
204 // Initialization
205 static void initialize(TRAPS);
206
207 public:
208 // Returns java system loader
209 static oop java_system_loader();
210
211 // Returns java platform loader
212 static oop java_platform_loader();
213
214 // Compute the java system and platform loaders
215 static void compute_java_loaders(TRAPS);
216
217 // Register a new class loader
218 static ClassLoaderData* register_loader(Handle class_loader, bool create_mirror_cld = false);
219
220 static void set_system_loader(ClassLoaderData *cld);
221 static void set_platform_loader(ClassLoaderData *cld);
222
223 static Symbol* check_signature_loaders(Symbol* signature, Klass* klass_being_linked,
224 Handle loader1, Handle loader2, bool is_method);
225
226 // JSR 292
227 // find a java.lang.invoke.MethodHandle.invoke* method for a given signature
228 // (asks Java to compute it if necessary, except in a compiler thread)
229 static Method* find_method_handle_invoker(Klass* klass,
230 Symbol* name,
231 Symbol* signature,
232 Klass* accessing_klass,
233 Handle *appendix_result,
234 TRAPS);
235 // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic)
236 // (does not ask Java, since this is a low-level intrinsic defined by the JVM)
237 static Method* find_method_handle_intrinsic(vmIntrinsicID iid,
238 Symbol* signature,
239 TRAPS);
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, Symbol* error,
283 Symbol* message, Symbol* cause = nullptr, Symbol* cause_msg = nullptr);
284 static void delete_resolution_error(ConstantPool* pool);
285 static Symbol* find_resolution_error(const constantPoolHandle& pool, int which,
286 Symbol** message, Symbol** cause, Symbol** cause_msg);
287
288
289 // Record a nest host resolution/validation error
290 static void add_nest_host_error(const constantPoolHandle& pool, int which,
291 const char* message);
292 static const char* find_nest_host_error(const constantPoolHandle& pool, int which);
293
294 protected:
295 static InstanceKlass* _well_known_klasses[];
296
297 private:
298 // table of box klasses (int_klass, etc.)
299 static InstanceKlass* _box_klasses[T_VOID+1];
300
301 static OopHandle _java_system_loader;
302 static OopHandle _java_platform_loader;
303
304 private:
305 // Basic loading operations
306 static InstanceKlass* resolve_instance_class_or_null(Symbol* class_name,
307 Handle class_loader,
308 Handle protection_domain, TRAPS);
309 static Klass* resolve_array_class_or_null(Symbol* class_name,
310 Handle class_loader,
311 Handle protection_domain, TRAPS);
312 static void define_instance_class(InstanceKlass* k, Handle class_loader, TRAPS);
313 static InstanceKlass* find_or_define_helper(Symbol* class_name,
314 Handle class_loader,
315 InstanceKlass* k, TRAPS);
316 static InstanceKlass* load_instance_class_impl(Symbol* class_name, Handle class_loader, TRAPS);
317 static InstanceKlass* load_instance_class(Symbol* class_name,
318 Handle class_loader, TRAPS);
319
320 // Class loader constraints
321 static void check_constraints(InstanceKlass* k, ClassLoaderData* loader,
322 bool defining, TRAPS);
323 static void update_dictionary(JavaThread* current, InstanceKlass* k, ClassLoaderData* loader_data);
324
325 static bool is_shared_class_visible(Symbol* class_name, InstanceKlass* ik,
326 PackageEntry* pkg_entry,
327 Handle class_loader);
328 static bool is_shared_class_visible_impl(Symbol* class_name,
329 InstanceKlass* ik,
330 PackageEntry* pkg_entry,
331 Handle class_loader);
332 static bool check_shared_class_super_type(InstanceKlass* klass, InstanceKlass* super,
333 Handle class_loader, Handle protection_domain,
334 bool is_superclass, TRAPS);
335 static bool check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
336 Handle protection_domain, TRAPS);
337 // Second part of load_shared_class
338 static void load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data) NOT_CDS_RETURN;
339
340 protected:
341 // Used by SystemDictionaryShared
342
343 static bool add_loader_constraint(Symbol* name, Klass* klass_being_linked, Handle loader1,
344 Handle loader2);
345 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld);
346 static InstanceKlass* load_shared_lambda_proxy_class(InstanceKlass* ik,
347 Handle class_loader,
348 Handle protection_domain,
349 PackageEntry* pkg_entry,
350 TRAPS);
351 static InstanceKlass* load_shared_class(InstanceKlass* ik,
352 Handle class_loader,
353 Handle protection_domain,
354 const ClassFileStream *cfs,
355 PackageEntry* pkg_entry,
356 TRAPS);
357 static Handle get_loader_lock_or_null(Handle class_loader);
358 static InstanceKlass* find_or_define_instance_class(Symbol* class_name,
359 Handle class_loader,
360 InstanceKlass* k, TRAPS);
361 public:
362 static bool is_system_class_loader(oop class_loader);
363 static bool is_platform_class_loader(oop class_loader);
364 static bool is_boot_class_loader(oop class_loader) { return class_loader == nullptr; }
365 static bool is_builtin_class_loader(oop class_loader) {
366 return is_boot_class_loader(class_loader) ||
367 is_platform_class_loader(class_loader) ||
368 is_system_class_loader(class_loader);
369 }
370 // Returns TRUE if the method is a non-public member of class java.lang.Object.
371 static bool is_nonpublic_Object_method(Method* m);
372
373 // Return Symbol or throw exception if name given is can not be a valid Symbol.
374 static Symbol* class_name_symbol(const char* name, Symbol* exception, TRAPS);
375 };
376
377 #endif // SHARE_CLASSFILE_SYSTEMDICTIONARY_HPP