1 /*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 // The system dictionary stores all loaded classes and maps:
26 //
27 // [class name,class loader] -> class i.e. [symbolOop,oop] -> klassOop
28 //
29 // Classes are loaded lazily. The default VM class loader is
30 // represented as NULL.
31
32 // The underlying data structure is an open hash table with a fixed number
33 // of buckets. During loading the loader object is locked, (for the VM loader
34 // a private lock object is used). Class loading can thus be done concurrently,
35 // but only by different loaders.
36 //
37 // During loading a placeholder (name, loader) is temporarily placed in
38 // a side data structure, and is used to detect ClassCircularityErrors
39 // and to perform verification during GC. A GC can occur in the midst
40 // of class loading, as we call out to Java, have to take locks, etc.
41 //
42 // When class loading is finished, a new entry is added to the system
43 // dictionary and the place holder is removed. Note that the protection
44 // domain field of the system dictionary has not yet been filled in when
45 // the "real" system dictionary entry is created.
46 //
47 // Clients of this class who are interested in finding if a class has
48 // been completely loaded -- not classes in the process of being loaded --
49 // can read the SystemDictionary unlocked. This is safe because
50 // - entries are only deleted at safepoints
51 // - readers cannot come to a safepoint while actively examining
52 // an entry (an entry cannot be deleted from under a reader)
53 // - entries must be fully formed before they are available to concurrent
54 // readers (we must ensure write ordering)
55 //
56 // Note that placeholders are deleted at any time, as they are removed
57 // when a class is completely loaded. Therefore, readers as well as writers
58 // of placeholders must hold the SystemDictionary_lock.
59 //
60
61 class Dictionary;
62 class PlaceholderTable;
63 class LoaderConstraintTable;
64 class HashtableBucket;
65 class ResolutionErrorTable;
66 class SymbolPropertyTable;
67
68 // Certain classes are preloaded, such as java.lang.Object and java.lang.String.
69 // They are all "well-known", in the sense that no class loader is allowed
70 // to provide a different definition.
71 //
72 // These klasses must all have names defined in vmSymbols.
73
74 #define WK_KLASS_ENUM_NAME(kname) kname##_knum
75
76 // Each well-known class has a short klass name (like object_klass),
77 // a vmSymbol name (like java_lang_Object), and a flag word
78 // that makes some minor distinctions, like whether the klass
79 // is preloaded, optional, release-specific, etc.
80 // The order of these definitions is significant; it is the order in which
81 // preloading is actually performed by initialize_preloaded_classes.
82
83 #define WK_KLASSES_DO(template) \
84 /* well-known classes */ \
85 template(Object_klass, java_lang_Object, Pre) \
86 template(String_klass, java_lang_String, Pre) \
87 template(Class_klass, java_lang_Class, Pre) \
88 template(Cloneable_klass, java_lang_Cloneable, Pre) \
89 template(ClassLoader_klass, java_lang_ClassLoader, Pre) \
90 template(Serializable_klass, java_io_Serializable, Pre) \
91 template(System_klass, java_lang_System, Pre) \
92 template(Throwable_klass, java_lang_Throwable, Pre) \
93 template(Error_klass, java_lang_Error, Pre) \
94 template(ThreadDeath_klass, java_lang_ThreadDeath, Pre) \
95 template(Exception_klass, java_lang_Exception, Pre) \
96 template(RuntimeException_klass, java_lang_RuntimeException, Pre) \
97 template(ProtectionDomain_klass, java_security_ProtectionDomain, Pre) \
98 template(AccessControlContext_klass, java_security_AccessControlContext, Pre) \
99 template(ClassNotFoundException_klass, java_lang_ClassNotFoundException, Pre) \
100 template(NoClassDefFoundError_klass, java_lang_NoClassDefFoundError, Pre) \
101 template(LinkageError_klass, java_lang_LinkageError, Pre) \
102 template(ClassCastException_klass, java_lang_ClassCastException, Pre) \
103 template(ArrayStoreException_klass, java_lang_ArrayStoreException, Pre) \
104 template(VirtualMachineError_klass, java_lang_VirtualMachineError, Pre) \
105 template(OutOfMemoryError_klass, java_lang_OutOfMemoryError, Pre) \
106 template(StackOverflowError_klass, java_lang_StackOverflowError, Pre) \
107 template(IllegalMonitorStateException_klass, java_lang_IllegalMonitorStateException, Pre) \
108 template(Reference_klass, java_lang_ref_Reference, Pre) \
109 \
110 /* Preload ref klasses and set reference types */ \
111 template(SoftReference_klass, java_lang_ref_SoftReference, Pre) \
112 template(WeakReference_klass, java_lang_ref_WeakReference, Pre) \
113 template(FinalReference_klass, java_lang_ref_FinalReference, Pre) \
114 template(PhantomReference_klass, java_lang_ref_PhantomReference, Pre) \
115 template(Finalizer_klass, java_lang_ref_Finalizer, Pre) \
116 \
117 template(Thread_klass, java_lang_Thread, Pre) \
118 template(ThreadGroup_klass, java_lang_ThreadGroup, Pre) \
119 template(Properties_klass, java_util_Properties, Pre) \
120 template(reflect_AccessibleObject_klass, java_lang_reflect_AccessibleObject, Pre) \
121 template(reflect_Field_klass, java_lang_reflect_Field, Pre) \
122 template(reflect_Method_klass, java_lang_reflect_Method, Pre) \
123 template(reflect_Constructor_klass, java_lang_reflect_Constructor, Pre) \
124 \
125 /* NOTE: needed too early in bootstrapping process to have checks based on JDK version */ \
126 /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \
127 /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \
128 template(reflect_MagicAccessorImpl_klass, sun_reflect_MagicAccessorImpl, Opt) \
129 template(reflect_MethodAccessorImpl_klass, sun_reflect_MethodAccessorImpl, Opt_Only_JDK14NewRef) \
130 template(reflect_ConstructorAccessorImpl_klass, sun_reflect_ConstructorAccessorImpl, Opt_Only_JDK14NewRef) \
131 template(reflect_DelegatingClassLoader_klass, sun_reflect_DelegatingClassLoader, Opt) \
132 template(reflect_ConstantPool_klass, sun_reflect_ConstantPool, Opt_Only_JDK15) \
133 template(reflect_UnsafeStaticFieldAccessorImpl_klass, sun_reflect_UnsafeStaticFieldAccessorImpl, Opt_Only_JDK15) \
134 \
135 /* support for dynamic typing; it's OK if these are NULL in earlier JDKs */ \
136 template(MethodHandle_klass, java_dyn_MethodHandle, Opt) \
137 template(MemberName_klass, sun_dyn_MemberName, Opt) \
138 template(MethodHandleImpl_klass, sun_dyn_MethodHandleImpl, Opt) \
139 template(MethodHandleNatives_klass, sun_dyn_MethodHandleNatives, Opt) \
140 template(AdapterMethodHandle_klass, sun_dyn_AdapterMethodHandle, Opt) \
141 template(BoundMethodHandle_klass, sun_dyn_BoundMethodHandle, Opt) \
142 template(DirectMethodHandle_klass, sun_dyn_DirectMethodHandle, Opt) \
143 template(MethodType_klass, java_dyn_MethodType, Opt) \
144 template(MethodTypeForm_klass, java_dyn_MethodTypeForm, Opt) \
145 template(WrongMethodTypeException_klass, java_dyn_WrongMethodTypeException, Opt) \
146 template(Linkage_klass, java_dyn_Linkage, Opt) \
147 template(CallSite_klass, java_dyn_CallSite, Opt) \
148 template(InvokeDynamic_klass, java_dyn_InvokeDynamic, Opt) \
149 /* Note: MethodHandle must be first, and InvokeDynamic last in group */ \
150 \
151 template(StringBuffer_klass, java_lang_StringBuffer, Pre) \
152 template(StringBuilder_klass, java_lang_StringBuilder, Pre) \
153 \
154 /* It's NULL in non-1.4 JDKs. */ \
155 template(StackTraceElement_klass, java_lang_StackTraceElement, Opt) \
156 /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \
157 /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \
158 template(java_nio_Buffer_klass, java_nio_Buffer, Opt) \
159 \
160 /* If this class isn't present, it won't be referenced. */ \
161 template(sun_misc_AtomicLongCSImpl_klass, sun_misc_AtomicLongCSImpl, Opt) \
162 \
163 template(sun_jkernel_DownloadManager_klass, sun_jkernel_DownloadManager, Opt_Kernel) \
164 \
165 /* Preload boxing klasses */ \
166 template(Boolean_klass, java_lang_Boolean, Pre) \
167 template(Character_klass, java_lang_Character, Pre) \
168 template(Float_klass, java_lang_Float, Pre) \
169 template(Double_klass, java_lang_Double, Pre) \
170 template(Byte_klass, java_lang_Byte, Pre) \
171 template(Short_klass, java_lang_Short, Pre) \
172 template(Integer_klass, java_lang_Integer, Pre) \
173 template(Long_klass, java_lang_Long, Pre) \
174 /*end*/
175
176
177 class SystemDictionary : AllStatic {
178 friend class VMStructs;
179 friend class CompactingPermGenGen;
180 friend class SystemDictionaryHandles;
181 NOT_PRODUCT(friend class instanceKlassKlass;)
182
183 public:
184 enum WKID {
185 NO_WKID = 0,
186
187 #define WK_KLASS_ENUM(name, ignore_s, ignore_o) WK_KLASS_ENUM_NAME(name),
188 WK_KLASSES_DO(WK_KLASS_ENUM)
189 #undef WK_KLASS_ENUM
190
191 WKID_LIMIT,
192
193 FIRST_WKID = NO_WKID + 1
194 };
195
196 enum InitOption {
197 Pre, // preloaded; error if not present
198
199 // Order is significant. Options before this point require resolve_or_fail.
200 // Options after this point will use resolve_or_null instead.
201
202 Opt, // preload tried; NULL if not present
203 Opt_Only_JDK14NewRef, // preload tried; use only with NewReflection
204 Opt_Only_JDK15, // preload tried; use only with JDK1.5+
205 Opt_Kernel, // preload tried only #ifdef KERNEL
206 OPTION_LIMIT,
207 CEIL_LG_OPTION_LIMIT = 4 // OPTION_LIMIT <= (1<<CEIL_LG_OPTION_LIMIT)
208 };
209
210
211 // Returns a class with a given class name and class loader. Loads the
212 // class if needed. If not found a NoClassDefFoundError or a
213 // ClassNotFoundException is thrown, depending on the value on the
214 // throw_error flag. For most uses the throw_error argument should be set
215 // to true.
216
217 static klassOop resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS);
218 // Convenient call for null loader and protection domain.
219 static klassOop resolve_or_fail(symbolHandle class_name, bool throw_error, TRAPS);
220 private:
221 // handle error translation for resolve_or_null results
222 static klassOop handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS);
223
224 public:
225
226 // Returns a class with a given class name and class loader.
227 // Loads the class if needed. If not found NULL is returned.
228 static klassOop resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS);
229 // Version with null loader and protection domain
230 static klassOop resolve_or_null(symbolHandle class_name, TRAPS);
231
232 // Resolve a superclass or superinterface. Called from ClassFileParser,
233 // parse_interfaces, resolve_instance_class_or_null, load_shared_class
234 // "child_name" is the class whose super class or interface is being resolved.
235 static klassOop resolve_super_or_fail(symbolHandle child_name,
236 symbolHandle class_name,
237 Handle class_loader,
238 Handle protection_domain,
239 bool is_superclass,
240 TRAPS);
241
242 // Parse new stream. This won't update the system dictionary or
243 // class hierarchy, simply parse the stream. Used by JVMTI RedefineClasses.
244 static klassOop parse_stream(symbolHandle class_name,
245 Handle class_loader,
246 Handle protection_domain,
247 ClassFileStream* st,
248 TRAPS) {
249 KlassHandle nullHandle;
250 return parse_stream(class_name, class_loader, protection_domain, st, nullHandle, NULL, THREAD);
251 }
252 static klassOop parse_stream(symbolHandle class_name,
253 Handle class_loader,
254 Handle protection_domain,
255 ClassFileStream* st,
256 KlassHandle host_klass,
257 GrowableArray<Handle>* cp_patches,
258 TRAPS);
259
260 // Resolve from stream (called by jni_DefineClass and JVM_DefineClass)
261 static klassOop resolve_from_stream(symbolHandle class_name, Handle class_loader,
262 Handle protection_domain,
263 ClassFileStream* st, bool verify, TRAPS);
264
265 // Lookup an already loaded class. If not found NULL is returned.
266 static klassOop find(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS);
267
268 // Lookup an already loaded instance or array class.
269 // Do not make any queries to class loaders; consult only the cache.
270 // If not found NULL is returned.
271 static klassOop find_instance_or_array_klass(symbolHandle class_name,
272 Handle class_loader,
273 Handle protection_domain,
274 TRAPS);
275
276 // If the given name is known to vmSymbols, return the well-know klass:
277 static klassOop find_well_known_klass(symbolOop class_name);
278
279 // Lookup an instance or array class that has already been loaded
280 // either into the given class loader, or else into another class
281 // loader that is constrained (via loader constraints) to produce
282 // a consistent class. Do not take protection domains into account.
283 // Do not make any queries to class loaders; consult only the cache.
284 // Return NULL if the class is not found.
285 //
286 // This function is a strict superset of find_instance_or_array_klass.
287 // This function (the unchecked version) makes a conservative prediction
288 // of the result of the checked version, assuming successful lookup.
289 // If both functions return non-null, they must return the same value.
290 // Also, the unchecked version may sometimes be non-null where the
291 // checked version is null. This can occur in several ways:
292 // 1. No query has yet been made to the class loader.
293 // 2. The class loader was queried, but chose not to delegate.
294 // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain.
295 // 4. Loading was attempted, but there was a linkage error of some sort.
296 // In all of these cases, the loader constraints on this type are
297 // satisfied, and it is safe for classes in the given class loader
298 // to manipulate strongly-typed values of the found class, subject
299 // to local linkage and access checks.
300 static klassOop find_constrained_instance_or_array_klass(symbolHandle class_name,
301 Handle class_loader,
302 TRAPS);
303
304 // Iterate over all klasses in dictionary
305 // Just the classes from defining class loaders
306 static void classes_do(void f(klassOop));
307 // Added for initialize_itable_for_klass to handle exceptions
308 static void classes_do(void f(klassOop, TRAPS), TRAPS);
309 // All classes, and their class loaders
310 static void classes_do(void f(klassOop, oop));
311 // All classes, and their class loaders
312 // (added for helpers that use HandleMarks and ResourceMarks)
313 static void classes_do(void f(klassOop, oop, TRAPS), TRAPS);
314 // All entries in the placeholder table and their class loaders
315 static void placeholders_do(void f(symbolOop, oop));
316
317 // Iterate over all methods in all klasses in dictionary
318 static void methods_do(void f(methodOop));
319
320 // Garbage collection support
321
322 // This method applies "blk->do_oop" to all the pointers to "system"
323 // classes and loaders.
324 static void always_strong_oops_do(OopClosure* blk);
325 static void always_strong_classes_do(OopClosure* blk);
326 // This method applies "blk->do_oop" to all the placeholders.
327 static void placeholders_do(OopClosure* blk);
328
329 // Unload (that is, break root links to) all unmarked classes and
330 // loaders. Returns "true" iff something was unloaded.
331 static bool do_unloading(BoolObjectClosure* is_alive);
332
333 // Applies "f->do_oop" to all root oops in the system dictionary.
334 static void oops_do(OopClosure* f);
335
336 // System loader lock
337 static oop system_loader_lock() { return _system_loader_lock_obj; }
338
339 private:
340 // Traverses preloaded oops: various system classes. These are
341 // guaranteed to be in the perm gen.
342 static void preloaded_oops_do(OopClosure* f);
343 static void lazily_loaded_oops_do(OopClosure* f);
344
345 public:
346 // Sharing support.
347 static void reorder_dictionary();
348 static void copy_buckets(char** top, char* end);
349 static void copy_table(char** top, char* end);
350 static void reverse();
351 static void set_shared_dictionary(HashtableBucket* t, int length,
352 int number_of_entries);
353 // Printing
354 static void print() PRODUCT_RETURN;
355 static void print_class_statistics() PRODUCT_RETURN;
356 static void print_method_statistics() PRODUCT_RETURN;
357
358 // Number of contained klasses
359 // This is both fully loaded classes and classes in the process
360 // of being loaded
361 static int number_of_classes();
362
363 // Monotonically increasing counter which grows as classes are
364 // loaded or modifications such as hot-swapping or setting/removing
365 // of breakpoints are performed
366 static inline int number_of_modifications() { assert_locked_or_safepoint(Compile_lock); return _number_of_modifications; }
367 // Needed by evolution and breakpoint code
368 static inline void notice_modification() { assert_locked_or_safepoint(Compile_lock); ++_number_of_modifications; }
369
370 // Verification
371 static void verify();
372
373 #ifdef ASSERT
374 static bool is_internal_format(symbolHandle class_name);
375 #endif
376
377 // Verify class is in dictionary
378 static void verify_obj_klass_present(Handle obj,
379 symbolHandle class_name,
380 Handle class_loader);
381
382 // Initialization
383 static void initialize(TRAPS);
384
385 // Fast access to commonly used classes (preloaded)
386 static klassOop check_klass(klassOop k) {
387 assert(k != NULL, "preloaded klass not initialized");
388 return k;
389 }
390
391 static klassOop check_klass_Pre(klassOop k) { return check_klass(k); }
392 static klassOop check_klass_Opt(klassOop k) { return k; }
393 static klassOop check_klass_Opt_Kernel(klassOop k) { return k; } //== Opt
394 static klassOop check_klass_Opt_Only_JDK15(klassOop k) {
395 assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only");
396 return k;
397 }
398 static klassOop check_klass_Opt_Only_JDK14NewRef(klassOop k) {
399 assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only");
400 // despite the optional loading, if you use this it must be present:
401 return check_klass(k);
402 }
403
404 static bool initialize_wk_klass(WKID id, int init_opt, TRAPS);
405 static void initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS);
406 static void initialize_wk_klasses_through(WKID end_id, WKID &start_id, TRAPS) {
407 int limit = (int)end_id + 1;
408 initialize_wk_klasses_until((WKID) limit, start_id, THREAD);
409 }
410
411 public:
412 #define WK_KLASS_DECLARE(name, ignore_symbol, option) \
413 static klassOop name() { return check_klass_##option(_well_known_klasses[WK_KLASS_ENUM_NAME(name)]); }
414 WK_KLASSES_DO(WK_KLASS_DECLARE);
415 #undef WK_KLASS_DECLARE
416
417 // Local definition for direct access to the private array:
418 #define WK_KLASS(name) _well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]
419
420 static klassOop box_klass(BasicType t) {
421 assert((uint)t < T_VOID+1, "range check");
422 return check_klass(_box_klasses[t]);
423 }
424 static BasicType box_klass_type(klassOop k); // inverse of box_klass
425
426 // methods returning lazily loaded klasses
427 // The corresponding method to load the class must be called before calling them.
428 static klassOop abstract_ownable_synchronizer_klass() { return check_klass(_abstract_ownable_synchronizer_klass); }
429
430 static void load_abstract_ownable_synchronizer_klass(TRAPS);
431
432 private:
433 // Tells whether ClassLoader.loadClassInternal is present
434 static bool has_loadClassInternal() { return _has_loadClassInternal; }
435
436 public:
437 // Tells whether ClassLoader.checkPackageAccess is present
438 static bool has_checkPackageAccess() { return _has_checkPackageAccess; }
439
440 static bool Class_klass_loaded() { return WK_KLASS(Class_klass) != NULL; }
441 static bool Cloneable_klass_loaded() { return WK_KLASS(Cloneable_klass) != NULL; }
442
443 // Returns default system loader
444 static oop java_system_loader();
445
446 // Compute the default system loader
447 static void compute_java_system_loader(TRAPS);
448
449 private:
450 // Mirrors for primitive classes (created eagerly)
451 static oop check_mirror(oop m) {
452 assert(m != NULL, "mirror not initialized");
453 return m;
454 }
455
456 public:
457 // Note: java_lang_Class::primitive_type is the inverse of java_mirror
458
459 // Check class loader constraints
460 static bool add_loader_constraint(symbolHandle name, Handle loader1,
461 Handle loader2, TRAPS);
462 static char* check_signature_loaders(symbolHandle signature, Handle loader1,
463 Handle loader2, bool is_method, TRAPS);
464
465 // JSR 292
466 // find the java.dyn.MethodHandles::invoke method for a given signature
467 static methodOop find_method_handle_invoke(symbolHandle name,
468 symbolHandle signature,
469 KlassHandle accessing_klass,
470 TRAPS);
471 // ask Java to compute a java.dyn.MethodType object for a given signature
472 static Handle find_method_handle_type(symbolHandle signature,
473 KlassHandle accessing_klass,
474 bool for_invokeGeneric,
475 bool& return_bcp_flag,
476 TRAPS);
477 // ask Java to compute a java.dyn.MethodHandle object for a given CP entry
478 static Handle link_method_handle_constant(KlassHandle caller,
479 int ref_kind, //e.g., JVM_REF_invokeVirtual
480 KlassHandle callee,
481 symbolHandle name,
482 symbolHandle signature,
483 TRAPS);
484 // ask Java to create a dynamic call site, while linking an invokedynamic op
485 static Handle make_dynamic_call_site(Handle bootstrap_method,
486 // Callee information:
487 symbolHandle name,
488 methodHandle signature_invoker,
489 Handle info,
490 // Caller information:
491 methodHandle caller_method,
492 int caller_bci,
493 TRAPS);
494
495 // coordinate with Java about bootstrap methods
496 static Handle find_bootstrap_method(methodHandle caller_method,
497 int caller_bci, // N.B. must be an invokedynamic
498 int cache_index, // must be corresponding main_entry
499 TRAPS);
500
501 // Utility for printing loader "name" as part of tracing constraints
502 static const char* loader_name(oop loader) {
503 return ((loader) == NULL ? "<bootloader>" :
504 instanceKlass::cast((loader)->klass())->name()->as_C_string() );
505 }
506
507 // Record the error when the first attempt to resolve a reference from a constant
508 // pool entry to a class fails.
509 static void add_resolution_error(constantPoolHandle pool, int which, symbolHandle error);
510 static symbolOop find_resolution_error(constantPoolHandle pool, int which);
511
512 private:
513
514 enum Constants {
515 _loader_constraint_size = 107, // number of entries in constraint table
516 _resolution_error_size = 107, // number of entries in resolution error table
517 _invoke_method_size = 139, // number of entries in invoke method table
518 _nof_buckets = 1009 // number of buckets in hash table
519 };
520
521
522 // Static variables
523
524 // Hashtable holding loaded classes.
525 static Dictionary* _dictionary;
526
527 // Hashtable holding placeholders for classes being loaded.
528 static PlaceholderTable* _placeholders;
529
530 // Hashtable holding classes from the shared archive.
531 static Dictionary* _shared_dictionary;
532
533 // Monotonically increasing counter which grows with
534 // _number_of_classes as well as hot-swapping and breakpoint setting
535 // and removal.
536 static int _number_of_modifications;
537
538 // Lock object for system class loader
539 static oop _system_loader_lock_obj;
540
541 // Constraints on class loaders
542 static LoaderConstraintTable* _loader_constraints;
543
544 // Resolution errors
545 static ResolutionErrorTable* _resolution_errors;
546
547 // Invoke methods (JSR 292)
548 static SymbolPropertyTable* _invoke_method_table;
549
550 public:
551 // for VM_CounterDecay iteration support
552 friend class CounterDecay;
553 static klassOop try_get_next_class();
554
555 private:
556 static void validate_protection_domain(instanceKlassHandle klass,
557 Handle class_loader,
558 Handle protection_domain, TRAPS);
559
560 friend class VM_PopulateDumpSharedSpace;
561 friend class TraversePlaceholdersClosure;
562 static Dictionary* dictionary() { return _dictionary; }
563 static Dictionary* shared_dictionary() { return _shared_dictionary; }
564 static PlaceholderTable* placeholders() { return _placeholders; }
565 static LoaderConstraintTable* constraints() { return _loader_constraints; }
566 static ResolutionErrorTable* resolution_errors() { return _resolution_errors; }
567 static SymbolPropertyTable* invoke_method_table() { return _invoke_method_table; }
568
569 // Basic loading operations
570 static klassOop resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS);
571 static klassOop resolve_array_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS);
572 static instanceKlassHandle handle_parallel_super_load(symbolHandle class_name, symbolHandle supername, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS);
573 // Wait on SystemDictionary_lock; unlocks lockObject before
574 // waiting; relocks lockObject with correct recursion count
575 // after waiting, but before reentering SystemDictionary_lock
576 // to preserve lock order semantics.
577 static void double_lock_wait(Handle lockObject, TRAPS);
578 static void define_instance_class(instanceKlassHandle k, TRAPS);
579 static instanceKlassHandle find_or_define_instance_class(symbolHandle class_name,
580 Handle class_loader,
581 instanceKlassHandle k, TRAPS);
582 static instanceKlassHandle load_shared_class(symbolHandle class_name,
583 Handle class_loader, TRAPS);
584 static instanceKlassHandle load_shared_class(instanceKlassHandle ik,
585 Handle class_loader, TRAPS);
586 static instanceKlassHandle load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS);
587 static Handle compute_loader_lock_object(Handle class_loader, TRAPS);
588 static void check_loader_lock_contention(Handle loader_lock, TRAPS);
589 static bool is_parallelCapable(Handle class_loader);
590 static bool is_parallelDefine(Handle class_loader);
591
592 static klassOop find_shared_class(symbolHandle class_name);
593
594 // Setup link to hierarchy
595 static void add_to_hierarchy(instanceKlassHandle k, TRAPS);
596
597 private:
598 // We pass in the hashtable index so we can calculate it outside of
599 // the SystemDictionary_lock.
600
601 // Basic find on loaded classes
602 static klassOop find_class(int index, unsigned int hash,
603 symbolHandle name, Handle loader);
604
605 // Basic find on classes in the midst of being loaded
606 static symbolOop find_placeholder(int index, unsigned int hash,
607 symbolHandle name, Handle loader);
608
609 // Basic find operation of loaded classes and classes in the midst
610 // of loading; used for assertions and verification only.
611 static oop find_class_or_placeholder(symbolHandle class_name,
612 Handle class_loader);
613
614 // Updating entry in dictionary
615 // Add a completely loaded class
616 static void add_klass(int index, symbolHandle class_name,
617 Handle class_loader, KlassHandle obj);
618
619 // Add a placeholder for a class being loaded
620 static void add_placeholder(int index,
621 symbolHandle class_name,
622 Handle class_loader);
623 static void remove_placeholder(int index,
624 symbolHandle class_name,
625 Handle class_loader);
626
627 // Performs cleanups after resolve_super_or_fail. This typically needs
628 // to be called on failure.
629 // Won't throw, but can block.
630 static void resolution_cleanups(symbolHandle class_name,
631 Handle class_loader,
632 TRAPS);
633
634 // Initialization
635 static void initialize_preloaded_classes(TRAPS);
636
637 // Class loader constraints
638 static void check_constraints(int index, unsigned int hash,
639 instanceKlassHandle k, Handle loader,
640 bool defining, TRAPS);
641 static void update_dictionary(int d_index, unsigned int d_hash,
642 int p_index, unsigned int p_hash,
643 instanceKlassHandle k, Handle loader, TRAPS);
644
645 // Variables holding commonly used klasses (preloaded)
646 static klassOop _well_known_klasses[];
647
648 // Lazily loaded klasses
649 static volatile klassOop _abstract_ownable_synchronizer_klass;
650
651 // table of box klasses (int_klass, etc.)
652 static klassOop _box_klasses[T_VOID+1];
653
654 static oop _java_system_loader;
655
656 static bool _has_loadClassInternal;
657 static bool _has_checkPackageAccess;
658 };
659
660 // Cf. vmSymbols vs. vmSymbolHandles
661 class SystemDictionaryHandles : AllStatic {
662 public:
663 #define WK_KLASS_HANDLE_DECLARE(name, ignore_symbol, option) \
664 static KlassHandle name() { \
665 SystemDictionary::name(); \
666 klassOop* loc = &SystemDictionary::_well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]; \
667 return KlassHandle(loc, true); \
668 }
669 WK_KLASSES_DO(WK_KLASS_HANDLE_DECLARE);
670 #undef WK_KLASS_HANDLE_DECLARE
671
672 static KlassHandle box_klass(BasicType t);
673 };