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 static InstanceKlass* resolve_with_circularity_detection(Symbol* class_name,
107 Symbol* next_name,
108 Handle class_loader,
109 Handle protection_domain,
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 Handle protection_domain, bool is_superclass, TRAPS) {
120 return resolve_with_circularity_detection(class_name, super_name, class_loader, protection_domain,
121 is_superclass, THREAD);
122 }
123
124 private:
125 // Parse the stream to create a hidden class.
126 // Used by jvm_lookup_define_class.
127 static InstanceKlass* resolve_hidden_class_from_stream(ClassFileStream* st,
128 Symbol* class_name,
129 Handle class_loader,
130 const ClassLoadInfo& cl_info,
131 TRAPS);
132
133 // Resolve a class from stream (called by jni_DefineClass and JVM_DefineClass)
134 // This class is added to the SystemDictionary.
135 static InstanceKlass* resolve_class_from_stream(ClassFileStream* st,
136 Symbol* class_name,
137 Handle class_loader,
138 const ClassLoadInfo& cl_info,
139 TRAPS);
140
141 static oop get_system_class_loader_impl(TRAPS);
142 static oop get_platform_class_loader_impl(TRAPS);
143
144 public:
145
146 // Resolve either a hidden or normal class from a stream of bytes, based on ClassLoadInfo
147 static InstanceKlass* resolve_from_stream(ClassFileStream* st,
148 Symbol* class_name,
149 Handle class_loader,
150 const ClassLoadInfo& cl_info,
151 TRAPS);
152
153 // Lookup an already loaded class. If not found null is returned.
154 static InstanceKlass* find_instance_klass(Thread* current, Symbol* class_name,
155 Handle class_loader, Handle protection_domain);
156
157 // Lookup an already loaded instance or array class.
158 // Do not make any queries to class loaders; consult only the cache.
159 // If not found null is returned.
160 static Klass* find_instance_or_array_klass(Thread* current, Symbol* class_name,
161 Handle class_loader,
162 Handle protection_domain);
163
164 // Lookup an instance or array class that has already been loaded
165 // either into the given class loader, or else into another class
166 // loader that is constrained (via loader constraints) to produce
167 // a consistent class. Do not take protection domains into account.
168 // Do not make any queries to class loaders; consult only the cache.
169 // Return null if the class is not found.
170 //
171 // This function is a strict superset of find_instance_or_array_klass.
172 // This function (the unchecked version) makes a conservative prediction
173 // of the result of the checked version, assuming successful lookup.
174 // If both functions return non-null, they must return the same value.
175 // Also, the unchecked version may sometimes be non-null where the
176 // checked version is null. This can occur in several ways:
177 // 1. No query has yet been made to the class loader.
178 // 2. The class loader was queried, but chose not to delegate.
179 // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain.
180 // 4. Loading was attempted, but there was a linkage error of some sort.
181 // In all of these cases, the loader constraints on this type are
182 // satisfied, and it is safe for classes in the given class loader
183 // to manipulate strongly-typed values of the found class, subject
184 // to local linkage and access checks.
185 static Klass* find_constrained_instance_or_array_klass(Thread* current,
186 Symbol* class_name,
187 Handle class_loader);
188
189 static void classes_do(MetaspaceClosure* it);
190 // Iterate over all methods in all klasses
191 // Will not keep metadata alive. See ClassLoaderDataGraph::methods_do.
192 static void methods_do(void f(Method*));
193
194 // Garbage collection support
195
196 // Unload (that is, break root links to) all unmarked classes and
197 // loaders. Returns "true" iff something was unloaded.
198 static bool do_unloading(GCTimer* gc_timer);
199
200 // Printing
201 static void print();
202 static void print_on(outputStream* st);
203 static void dump(outputStream* st, bool verbose);
204
205 // Verification
206 static void verify();
207
208 // Initialization
209 static void initialize(TRAPS);
210
211 public:
212 // Returns java system loader
213 static oop java_system_loader();
214
215 // Returns java platform loader
216 static oop java_platform_loader();
217
218 // Compute the java system and platform loaders
219 static void compute_java_loaders(TRAPS);
220
221 // Register a new class loader
222 static ClassLoaderData* register_loader(Handle class_loader, bool create_mirror_cld = false);
223
224 static void set_system_loader(ClassLoaderData *cld);
225 static void set_platform_loader(ClassLoaderData *cld);
226
227 static Symbol* check_signature_loaders(Symbol* signature, Klass* klass_being_linked,
228 Handle loader1, Handle loader2, bool is_method);
229
230 // JSR 292
231 // find a java.lang.invoke.MethodHandle.invoke* method for a given signature
232 // (asks Java to compute it if necessary, except in a compiler thread)
233 static Method* find_method_handle_invoker(Klass* klass,
234 Symbol* name,
235 Symbol* signature,
236 Klass* accessing_klass,
237 Handle *appendix_result,
238 TRAPS);
239 // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic)
240 // (does not ask Java, since this is a low-level intrinsic defined by the JVM)
241 static Method* find_method_handle_intrinsic(vmIntrinsicID iid,
242 Symbol* signature,
243 TRAPS);
244
245 // compute java_mirror (java.lang.Class instance) for a type ("I", "[[B", "LFoo;", etc.)
246 // Either the accessing_klass or the CL/PD can be non-null, but not both.
247 static Handle find_java_mirror_for_type(Symbol* signature,
248 Klass* accessing_klass,
249 Handle class_loader,
250 Handle protection_domain,
251 SignatureStream::FailureMode failure_mode,
252 TRAPS);
253 static Handle find_java_mirror_for_type(Symbol* signature,
254 Klass* accessing_klass,
255 SignatureStream::FailureMode failure_mode,
256 TRAPS) {
257 // callee will fill in CL/PD from AK, if they are needed
258 return find_java_mirror_for_type(signature, accessing_klass, Handle(), Handle(),
259 failure_mode, THREAD);
260 }
261
262 // find a java.lang.invoke.MethodType object for a given signature
263 // (asks Java to compute it if necessary, except in a compiler thread)
264 static Handle find_method_handle_type(Symbol* signature,
265 Klass* accessing_klass,
266 TRAPS);
267
268 // find a java.lang.Class object for a given signature
269 static Handle find_field_handle_type(Symbol* signature,
270 Klass* accessing_klass,
271 TRAPS);
272
273 // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
274 static Handle link_method_handle_constant(Klass* caller,
275 int ref_kind, //e.g., JVM_REF_invokeVirtual
276 Klass* callee,
277 Symbol* name,
278 Symbol* signature,
279 TRAPS);
280
281 // ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
282 static void invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS);
283
284 // Record the error when the first attempt to resolve a reference from a constant
285 // pool entry to a class fails.
286 static void add_resolution_error(const constantPoolHandle& pool, int which,
287 Symbol* error, const char* message,
288 Symbol* cause = nullptr, const char* cause_msg = nullptr);
289 static void delete_resolution_error(ConstantPool* pool);
290 static Symbol* find_resolution_error(const constantPoolHandle& pool, int which,
291 const char** message,
292 Symbol** cause, const char** cause_msg);
293
294 // Record a nest host resolution/validation error
295 static void add_nest_host_error(const constantPoolHandle& pool, int which,
296 const char* message);
297 static const char* find_nest_host_error(const constantPoolHandle& pool, int which);
298
299 static OopHandle _java_system_loader;
300 static OopHandle _java_platform_loader;
301
302 private:
303 // Basic loading operations
304 static InstanceKlass* resolve_instance_class_or_null(Symbol* class_name,
305 Handle class_loader,
306 Handle protection_domain, TRAPS);
307 static Klass* resolve_array_class_or_null(Symbol* class_name,
308 Handle class_loader,
309 Handle protection_domain, TRAPS);
310 static void define_instance_class(InstanceKlass* k, Handle class_loader, TRAPS);
311 static InstanceKlass* find_or_define_helper(Symbol* class_name,
312 Handle class_loader,
313 InstanceKlass* k, TRAPS);
314 static InstanceKlass* load_instance_class_impl(Symbol* class_name, Handle class_loader, TRAPS);
315 static InstanceKlass* load_instance_class(Symbol* class_name,
316 Handle class_loader, TRAPS);
317
318 // Class loader constraints
319 static void check_constraints(InstanceKlass* k, ClassLoaderData* loader,
320 bool defining, TRAPS);
321 static void update_dictionary(JavaThread* current, InstanceKlass* k, ClassLoaderData* loader_data);
322
323 static bool is_shared_class_visible(Symbol* class_name, InstanceKlass* ik,
324 PackageEntry* pkg_entry,
325 Handle class_loader);
326 static bool is_shared_class_visible_impl(Symbol* class_name,
327 InstanceKlass* ik,
328 PackageEntry* pkg_entry,
329 Handle class_loader);
330 static bool check_shared_class_super_type(InstanceKlass* klass, InstanceKlass* super,
331 Handle class_loader, Handle protection_domain,
332 bool is_superclass, TRAPS);
333 static bool check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
334 Handle protection_domain, TRAPS);
335 // Second part of load_shared_class
336 static void load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data) NOT_CDS_RETURN;
337
338 protected:
339 // Used by SystemDictionaryShared
340
341 static bool add_loader_constraint(Symbol* name, Klass* klass_being_linked, Handle loader1,
342 Handle loader2);
343 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld);
344 static InstanceKlass* load_shared_lambda_proxy_class(InstanceKlass* ik,
345 Handle class_loader,
346 Handle protection_domain,
347 PackageEntry* pkg_entry,
348 TRAPS);
349 static InstanceKlass* load_shared_class(InstanceKlass* ik,
350 Handle class_loader,
351 Handle protection_domain,
352 const ClassFileStream *cfs,
353 PackageEntry* pkg_entry,
354 TRAPS);
355 static Handle get_loader_lock_or_null(Handle class_loader);
356 static InstanceKlass* find_or_define_instance_class(Symbol* class_name,
357 Handle class_loader,
358 InstanceKlass* k, TRAPS);
359 public:
360 static bool is_system_class_loader(oop class_loader);
361 static bool is_platform_class_loader(oop class_loader);
362 static bool is_boot_class_loader(oop class_loader) { return class_loader == nullptr; }
363 static bool is_builtin_class_loader(oop class_loader) {
364 return is_boot_class_loader(class_loader) ||
365 is_platform_class_loader(class_loader) ||
366 is_system_class_loader(class_loader);
367 }
368 // Returns TRUE if the method is a non-public member of class java.lang.Object.
369 static bool is_nonpublic_Object_method(Method* m);
370
371 // Return Symbol or throw exception if name given is can not be a valid Symbol.
372 static Symbol* class_name_symbol(const char* name, Symbol* exception, TRAPS);
373 };
374
375 #endif // SHARE_CLASSFILE_SYSTEMDICTIONARY_HPP