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 PackageEntry;
72 class GCTimer;
73 class EventClassLoad;
74 class Symbol;
75
76 template <class E> class GrowableArray;
77
78 class SystemDictionary : AllStatic {
79 friend class AOTLinkedClassBulkLoader;
80 friend class BootstrapInfo;
81 friend class LambdaProxyClassDictionary;
82 friend class vmClasses;
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, 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(), 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, 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(), THREAD);
104 }
105
106 static InstanceKlass* resolve_with_circularity_detection(Symbol* class_name,
107 Symbol* next_name,
108 Handle class_loader,
109 bool is_superclass,
110 TRAPS);
111
112 // Resolve a superclass or superinterface. Called from ClassFileParser,
113 // parse_interfaces, resolve_instance_class_or_null, load_shared_class
114 // "class_name" is the class whose super class or interface is being resolved.
115 static InstanceKlass* resolve_super_or_fail(Symbol* class_name, Symbol* super_name,
116 Handle class_loader,
117 bool is_superclass, TRAPS) {
118 return resolve_with_circularity_detection(class_name, super_name, class_loader, is_superclass, THREAD);
119 }
120
121 private:
122 // Parse the stream to create a hidden class.
123 // Used by jvm_lookup_define_class.
124 static InstanceKlass* resolve_hidden_class_from_stream(ClassFileStream* st,
125 Symbol* class_name,
126 Handle class_loader,
127 const ClassLoadInfo& cl_info,
128 TRAPS);
129
130 // Resolve a class from stream (called by jni_DefineClass and JVM_DefineClass)
131 // This class is added to the SystemDictionary.
132 static InstanceKlass* resolve_class_from_stream(ClassFileStream* st,
133 Symbol* class_name,
134 Handle class_loader,
135 const ClassLoadInfo& cl_info,
136 TRAPS);
137
138 static oop get_system_class_loader_impl(TRAPS);
139 static oop get_platform_class_loader_impl(TRAPS);
140
141 public:
142
143 // Resolve either a hidden or normal class from a stream of bytes, based on ClassLoadInfo
144 static InstanceKlass* resolve_from_stream(ClassFileStream* st,
145 Symbol* class_name,
146 Handle class_loader,
147 const ClassLoadInfo& cl_info,
148 TRAPS);
149
150 // Lookup an already loaded class. If not found null is returned.
151 static InstanceKlass* find_instance_klass(Thread* current, Symbol* class_name,
152 Handle class_loader);
153
154 // Lookup an already loaded instance or array class.
155 // Do not make any queries to class loaders; consult only the cache.
156 // If not found null is returned.
157 static Klass* find_instance_or_array_klass(Thread* current, Symbol* class_name,
158 Handle class_loader);
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 // Will not keep metadata alive. See ClassLoaderDataGraph::methods_do.
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 static void get_all_method_handle_intrinsics(GrowableArray<Method*>* methods) NOT_CDS_RETURN;
242 static void restore_archived_method_handle_intrinsics() NOT_CDS_RETURN;
243
244 // compute java_mirror (java.lang.Class instance) for a type ("I", "[[B", "LFoo;", etc.)
245 static Handle find_java_mirror_for_type(Symbol* signature,
246 Klass* accessing_klass,
247 SignatureStream::FailureMode failure_mode,
248 TRAPS);
249
250 // find a java.lang.invoke.MethodType object for a given signature
251 // (asks Java to compute it if necessary, except in a compiler thread)
252 static Handle find_method_handle_type(Symbol* signature,
253 Klass* accessing_klass,
254 TRAPS);
255
256 // find a java.lang.Class object for a given signature
257 static Handle find_field_handle_type(Symbol* signature,
258 Klass* accessing_klass,
259 TRAPS);
260
261 // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
262 static Handle link_method_handle_constant(Klass* caller,
263 int ref_kind, //e.g., JVM_REF_invokeVirtual
264 Klass* callee,
265 Symbol* name,
266 Symbol* signature,
267 TRAPS);
268
269 // ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
270 static void invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS);
271
272 // Record the error when the first attempt to resolve a reference from a constant
273 // pool entry to a class fails.
274 static void add_resolution_error(const constantPoolHandle& pool, int which,
275 Symbol* error, const char* message,
276 Symbol* cause = nullptr, const char* cause_msg = nullptr);
277 static void delete_resolution_error(ConstantPool* pool);
278 static Symbol* find_resolution_error(const constantPoolHandle& pool, int which,
279 const char** message,
280 Symbol** cause, const char** cause_msg);
281
282 // Record a nest host resolution/validation error
283 static void add_nest_host_error(const constantPoolHandle& pool, int which,
284 const char* message);
285 static const char* find_nest_host_error(const constantPoolHandle& pool, int which);
286
287 static void add_to_initiating_loader(JavaThread* current, InstanceKlass* k,
288 ClassLoaderData* loader_data);
289
290 static OopHandle _java_system_loader;
291 static OopHandle _java_platform_loader;
292
293 private:
294 // Basic loading operations
295 static InstanceKlass* resolve_instance_class_or_null(Symbol* class_name,
296 Handle class_loader,
297 TRAPS);
298 static Klass* resolve_array_class_or_null(Symbol* class_name,
299 Handle class_loader,
300 TRAPS);
301 static void define_instance_class(InstanceKlass* k, Handle class_loader, TRAPS);
302 static InstanceKlass* find_or_define_helper(Symbol* class_name,
303 Handle class_loader,
304 InstanceKlass* k, TRAPS);
305 static InstanceKlass* load_instance_class_impl(Symbol* class_name, Handle class_loader, TRAPS);
306 static InstanceKlass* load_instance_class(Symbol* class_name,
307 Handle class_loader, TRAPS);
308
309 // Class loader constraints
310 static void check_constraints(InstanceKlass* k, ClassLoaderData* loader,
311 bool defining, TRAPS);
312 static void update_dictionary(JavaThread* current, InstanceKlass* k, ClassLoaderData* loader_data);
313
314 static bool is_shared_class_visible(Symbol* class_name, InstanceKlass* ik,
315 PackageEntry* pkg_entry,
316 Handle class_loader);
317 static bool is_shared_class_visible_impl(Symbol* class_name,
318 InstanceKlass* ik,
319 PackageEntry* pkg_entry,
320 Handle class_loader);
321 static bool check_shared_class_super_type(InstanceKlass* klass, InstanceKlass* super,
322 Handle class_loader,
323 bool is_superclass, TRAPS);
324 static bool check_shared_class_super_types(InstanceKlass* ik, Handle class_loader, TRAPS);
325 // Second part of load_shared_class
326 static void load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data) NOT_CDS_RETURN;
327 static void restore_archived_method_handle_intrinsics_impl(TRAPS) NOT_CDS_RETURN;
328
329 protected:
330 // Used by SystemDictionaryShared and LambdaProxyClassDictionary
331
332 static bool add_loader_constraint(Symbol* name, Klass* klass_being_linked, Handle loader1,
333 Handle loader2);
334 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld);
335 static bool preload_from_null_free_field(InstanceKlass* ik, Handle class_loader, Symbol* sig, int field_index, TRAPS);
336 static void try_preload_from_loadable_descriptors(InstanceKlass* ik, Handle class_loader, Symbol* sig, int field_index, TRAPS);
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