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