1 /*
2 * Copyright (c) 1997, 2019, 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,
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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
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23 */
24
25 #ifndef SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP
26 #define SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP
27
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "oops/objArrayOop.hpp"
31 #include "oops/symbol.hpp"
32 #include "runtime/java.hpp"
33 #include "runtime/reflectionUtils.hpp"
34 #include "utilities/hashtable.hpp"
35 #include "utilities/hashtable.inline.hpp"
36
37
38 // The system dictionary stores all loaded classes and maps:
39 //
40 // [class name,class loader] -> class i.e. [Symbol*,oop] -> Klass*
41 //
42 // Classes are loaded lazily. The default VM class loader is
43 // represented as NULL.
44
45 // The underlying data structure is an open hash table with a fixed number
46 // of buckets. During loading the loader object is locked, (for the VM loader
47 // a private lock object is used). Class loading can thus be done concurrently,
48 // but only by different loaders.
49 //
50 // During loading a placeholder (name, loader) is temporarily placed in
51 // a side data structure, and is used to detect ClassCircularityErrors
52 // and to perform verification during GC. A GC can occur in the midst
53 // of class loading, as we call out to Java, have to take locks, etc.
54 //
55 // When class loading is finished, a new entry is added to the system
56 // dictionary and the place holder is removed. Note that the protection
57 // domain field of the system dictionary has not yet been filled in when
58 // the "real" system dictionary entry is created.
59 //
60 // Clients of this class who are interested in finding if a class has
61 // been completely loaded -- not classes in the process of being loaded --
62 // can read the SystemDictionary unlocked. This is safe because
63 // - entries are only deleted at safepoints
64 // - readers cannot come to a safepoint while actively examining
65 // an entry (an entry cannot be deleted from under a reader)
66 // - entries must be fully formed before they are available to concurrent
67 // readers (we must ensure write ordering)
68 //
69 // Note that placeholders are deleted at any time, as they are removed
70 // when a class is completely loaded. Therefore, readers as well as writers
71 // of placeholders must hold the SystemDictionary_lock.
72 //
73
74 class Dictionary;
75 class PlaceholderTable;
76 class LoaderConstraintTable;
77 template <MEMFLAGS F> class HashtableBucket;
78 class ResolutionErrorTable;
79 class SymbolPropertyTable;
80
81 // Certain classes are preloaded, such as java.lang.Object and java.lang.String.
82 // They are all "well-known", in the sense that no class loader is allowed
83 // to provide a different definition.
84 //
85 // These klasses must all have names defined in vmSymbols.
86
87 #define WK_KLASS_ENUM_NAME(kname) kname##_knum
88
89 // Each well-known class has a short klass name (like object_klass),
90 // a vmSymbol name (like java_lang_Object), and a flag word
91 // that makes some minor distinctions, like whether the klass
92 // is preloaded, optional, release-specific, etc.
93 // The order of these definitions is significant; it is the order in which
94 // preloading is actually performed by initialize_preloaded_classes.
95
96 #define WK_KLASSES_DO(do_klass) \
97 /* well-known classes */ \
98 do_klass(Object_klass, java_lang_Object, Pre ) \
99 do_klass(String_klass, java_lang_String, Pre ) \
100 do_klass(Class_klass, java_lang_Class, Pre ) \
101 do_klass(Cloneable_klass, java_lang_Cloneable, Pre ) \
102 do_klass(ClassLoader_klass, java_lang_ClassLoader, Pre ) \
103 do_klass(Serializable_klass, java_io_Serializable, Pre ) \
104 do_klass(System_klass, java_lang_System, Pre ) \
105 do_klass(Throwable_klass, java_lang_Throwable, Pre ) \
106 do_klass(Error_klass, java_lang_Error, Pre ) \
107 do_klass(ThreadDeath_klass, java_lang_ThreadDeath, Pre ) \
108 do_klass(Exception_klass, java_lang_Exception, Pre ) \
109 do_klass(RuntimeException_klass, java_lang_RuntimeException, Pre ) \
110 do_klass(SecurityManager_klass, java_lang_SecurityManager, Pre ) \
111 do_klass(ProtectionDomain_klass, java_security_ProtectionDomain, Pre ) \
112 do_klass(AccessControlContext_klass, java_security_AccessControlContext, Pre ) \
113 do_klass(SecureClassLoader_klass, java_security_SecureClassLoader, Pre ) \
114 do_klass(ClassNotFoundException_klass, java_lang_ClassNotFoundException, Pre ) \
115 do_klass(NoClassDefFoundError_klass, java_lang_NoClassDefFoundError, Pre ) \
116 do_klass(LinkageError_klass, java_lang_LinkageError, Pre ) \
117 do_klass(ClassCastException_klass, java_lang_ClassCastException, Pre ) \
118 do_klass(ArrayStoreException_klass, java_lang_ArrayStoreException, Pre ) \
119 do_klass(VirtualMachineError_klass, java_lang_VirtualMachineError, Pre ) \
120 do_klass(OutOfMemoryError_klass, java_lang_OutOfMemoryError, Pre ) \
121 do_klass(StackOverflowError_klass, java_lang_StackOverflowError, Pre ) \
122 do_klass(IllegalMonitorStateException_klass, java_lang_IllegalMonitorStateException, Pre ) \
123 do_klass(Reference_klass, java_lang_ref_Reference, Pre ) \
124 \
125 /* Preload ref klasses and set reference types */ \
126 do_klass(SoftReference_klass, java_lang_ref_SoftReference, Pre ) \
127 do_klass(WeakReference_klass, java_lang_ref_WeakReference, Pre ) \
128 do_klass(FinalReference_klass, java_lang_ref_FinalReference, Pre ) \
129 do_klass(PhantomReference_klass, java_lang_ref_PhantomReference, Pre ) \
130 do_klass(Cleaner_klass, sun_misc_Cleaner, Pre ) \
131 do_klass(Finalizer_klass, java_lang_ref_Finalizer, Pre ) \
132 do_klass(ReferenceQueue_klass, java_lang_ref_ReferenceQueue, Pre ) \
133 \
134 do_klass(Thread_klass, java_lang_Thread, Pre ) \
135 do_klass(ThreadGroup_klass, java_lang_ThreadGroup, Pre ) \
136 do_klass(Properties_klass, java_util_Properties, Pre ) \
137 do_klass(reflect_AccessibleObject_klass, java_lang_reflect_AccessibleObject, Pre ) \
138 do_klass(reflect_Field_klass, java_lang_reflect_Field, Pre ) \
139 do_klass(reflect_Parameter_klass, java_lang_reflect_Parameter, Opt ) \
140 do_klass(reflect_Method_klass, java_lang_reflect_Method, Pre ) \
141 do_klass(reflect_Constructor_klass, java_lang_reflect_Constructor, Pre ) \
142 \
143 /* NOTE: needed too early in bootstrapping process to have checks based on JDK version */ \
144 /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \
145 /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \
146 do_klass(reflect_MagicAccessorImpl_klass, sun_reflect_MagicAccessorImpl, Opt ) \
147 do_klass(reflect_MethodAccessorImpl_klass, sun_reflect_MethodAccessorImpl, Opt_Only_JDK14NewRef) \
148 do_klass(reflect_ConstructorAccessorImpl_klass, sun_reflect_ConstructorAccessorImpl, Opt_Only_JDK14NewRef) \
149 do_klass(reflect_DelegatingClassLoader_klass, sun_reflect_DelegatingClassLoader, Opt ) \
150 do_klass(reflect_ConstantPool_klass, sun_reflect_ConstantPool, Opt_Only_JDK15 ) \
151 do_klass(reflect_UnsafeStaticFieldAccessorImpl_klass, sun_reflect_UnsafeStaticFieldAccessorImpl, Opt_Only_JDK15 ) \
152 do_klass(reflect_CallerSensitive_klass, sun_reflect_CallerSensitive, Opt ) \
153 \
154 /* support for dynamic typing; it's OK if these are NULL in earlier JDKs */ \
155 do_klass(DirectMethodHandle_klass, java_lang_invoke_DirectMethodHandle, Opt ) \
156 do_klass(MethodHandle_klass, java_lang_invoke_MethodHandle, Pre_JSR292 ) \
157 do_klass(MemberName_klass, java_lang_invoke_MemberName, Pre_JSR292 ) \
158 do_klass(MethodHandleNatives_klass, java_lang_invoke_MethodHandleNatives, Pre_JSR292 ) \
159 do_klass(LambdaForm_klass, java_lang_invoke_LambdaForm, Opt ) \
160 do_klass(MethodType_klass, java_lang_invoke_MethodType, Pre_JSR292 ) \
161 do_klass(BootstrapMethodError_klass, java_lang_BootstrapMethodError, Pre_JSR292 ) \
162 do_klass(CallSite_klass, java_lang_invoke_CallSite, Pre_JSR292 ) \
163 do_klass(ConstantCallSite_klass, java_lang_invoke_ConstantCallSite, Pre_JSR292 ) \
164 do_klass(MutableCallSite_klass, java_lang_invoke_MutableCallSite, Pre_JSR292 ) \
165 do_klass(VolatileCallSite_klass, java_lang_invoke_VolatileCallSite, Pre_JSR292 ) \
166 /* Note: MethodHandle must be first, and VolatileCallSite last in group */ \
167 \
168 do_klass(StringBuffer_klass, java_lang_StringBuffer, Pre ) \
169 do_klass(StringBuilder_klass, java_lang_StringBuilder, Pre ) \
170 do_klass(misc_Unsafe_klass, sun_misc_Unsafe, Pre ) \
171 \
172 /* support for CDS */ \
173 do_klass(ByteArrayInputStream_klass, java_io_ByteArrayInputStream, Pre ) \
174 do_klass(File_klass, java_io_File, Pre ) \
175 do_klass(URLClassLoader_klass, java_net_URLClassLoader, Pre ) \
176 do_klass(URL_klass, java_net_URL, Pre ) \
177 do_klass(Jar_Manifest_klass, java_util_jar_Manifest, Pre ) \
178 do_klass(sun_misc_Launcher_klass, sun_misc_Launcher, Pre ) \
179 do_klass(sun_misc_Launcher_AppClassLoader_klass, sun_misc_Launcher_AppClassLoader, Pre ) \
180 do_klass(sun_misc_Launcher_ExtClassLoader_klass, sun_misc_Launcher_ExtClassLoader, Pre ) \
181 do_klass(CodeSource_klass, java_security_CodeSource, Pre ) \
182 \
183 /* It's NULL in non-1.4 JDKs. */ \
184 do_klass(StackTraceElement_klass, java_lang_StackTraceElement, Opt ) \
185 /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \
186 /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \
187 do_klass(nio_Buffer_klass, java_nio_Buffer, Opt ) \
188 \
189 /* Preload boxing klasses */ \
190 do_klass(Boolean_klass, java_lang_Boolean, Pre ) \
191 do_klass(Character_klass, java_lang_Character, Pre ) \
192 do_klass(Float_klass, java_lang_Float, Pre ) \
193 do_klass(Double_klass, java_lang_Double, Pre ) \
194 do_klass(Byte_klass, java_lang_Byte, Pre ) \
195 do_klass(Short_klass, java_lang_Short, Pre ) \
196 do_klass(Integer_klass, java_lang_Integer, Pre ) \
197 do_klass(Long_klass, java_lang_Long, Pre ) \
198 /*end*/
199
200
201 class SystemDictionary : AllStatic {
202 friend class VMStructs;
203 friend class SystemDictionaryHandles;
204
205 public:
206 enum WKID {
207 NO_WKID = 0,
208
209 #define WK_KLASS_ENUM(name, symbol, ignore_o) WK_KLASS_ENUM_NAME(name), WK_KLASS_ENUM_NAME(symbol) = WK_KLASS_ENUM_NAME(name),
210 WK_KLASSES_DO(WK_KLASS_ENUM)
211 #undef WK_KLASS_ENUM
212
213 WKID_LIMIT,
214
215 FIRST_WKID = NO_WKID + 1
216 };
217
218 enum InitOption {
219 Pre, // preloaded; error if not present
220 Pre_JSR292, // preloaded if EnableInvokeDynamic
221
222 // Order is significant. Options before this point require resolve_or_fail.
223 // Options after this point will use resolve_or_null instead.
224
225 Opt, // preload tried; NULL if not present
226 Opt_Only_JDK14NewRef, // preload tried; use only with NewReflection
227 Opt_Only_JDK15, // preload tried; use only with JDK1.5+
228 OPTION_LIMIT,
229 CEIL_LG_OPTION_LIMIT = 4 // OPTION_LIMIT <= (1<<CEIL_LG_OPTION_LIMIT)
230 };
231
232
233 // Returns a class with a given class name and class loader. Loads the
234 // class if needed. If not found a NoClassDefFoundError or a
235 // ClassNotFoundException is thrown, depending on the value on the
236 // throw_error flag. For most uses the throw_error argument should be set
237 // to true.
238
239 static Klass* resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS);
240 // Convenient call for null loader and protection domain.
241 static Klass* resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS);
242 protected:
243 // handle error translation for resolve_or_null results
244 static Klass* handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS);
245
246 public:
247
248 // Returns a class with a given class name and class loader.
249 // Loads the class if needed. If not found NULL is returned.
250 static Klass* resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
251 // Version with null loader and protection domain
252 static Klass* resolve_or_null(Symbol* class_name, TRAPS);
253
254 // Resolve a superclass or superinterface. Called from ClassFileParser,
255 // parse_interfaces, resolve_instance_class_or_null, load_shared_class
256 // "child_name" is the class whose super class or interface is being resolved.
257 static Klass* resolve_super_or_fail(Symbol* child_name,
258 Symbol* class_name,
259 Handle class_loader,
260 Handle protection_domain,
261 bool is_superclass,
262 TRAPS);
263
264 // Parse new stream. This won't update the system dictionary or
265 // class hierarchy, simply parse the stream. Used by JVMTI RedefineClasses.
266 static Klass* parse_stream(Symbol* class_name,
267 Handle class_loader,
268 Handle protection_domain,
269 ClassFileStream* st,
270 TRAPS) {
271 KlassHandle nullHandle;
272 return parse_stream(class_name, class_loader, protection_domain, st, nullHandle, NULL, THREAD);
273 }
274 static Klass* parse_stream(Symbol* class_name,
275 Handle class_loader,
276 Handle protection_domain,
277 ClassFileStream* st,
278 KlassHandle host_klass,
279 GrowableArray<Handle>* cp_patches,
280 TRAPS);
281
282 // Resolve from stream (called by jni_DefineClass and JVM_DefineClass)
283 static Klass* resolve_from_stream(Symbol* class_name, Handle class_loader,
284 Handle protection_domain,
285 ClassFileStream* st, bool verify, TRAPS);
286
287 // Lookup an already loaded class. If not found NULL is returned.
288 static Klass* find(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
289
290 // Lookup an already loaded instance or array class.
291 // Do not make any queries to class loaders; consult only the cache.
292 // If not found NULL is returned.
293 static Klass* find_instance_or_array_klass(Symbol* class_name,
294 Handle class_loader,
295 Handle protection_domain,
296 TRAPS);
297
298 // Lookup an instance or array class that has already been loaded
299 // either into the given class loader, or else into another class
300 // loader that is constrained (via loader constraints) to produce
301 // a consistent class. Do not take protection domains into account.
302 // Do not make any queries to class loaders; consult only the cache.
303 // Return NULL if the class is not found.
304 //
305 // This function is a strict superset of find_instance_or_array_klass.
306 // This function (the unchecked version) makes a conservative prediction
307 // of the result of the checked version, assuming successful lookup.
308 // If both functions return non-null, they must return the same value.
309 // Also, the unchecked version may sometimes be non-null where the
310 // checked version is null. This can occur in several ways:
311 // 1. No query has yet been made to the class loader.
312 // 2. The class loader was queried, but chose not to delegate.
313 // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain.
314 // 4. Loading was attempted, but there was a linkage error of some sort.
315 // In all of these cases, the loader constraints on this type are
316 // satisfied, and it is safe for classes in the given class loader
317 // to manipulate strongly-typed values of the found class, subject
318 // to local linkage and access checks.
319 static Klass* find_constrained_instance_or_array_klass(Symbol* class_name,
320 Handle class_loader,
321 TRAPS);
322
323 // Iterate over all klasses in dictionary
324 // Just the classes from defining class loaders
325 static void classes_do(void f(Klass*));
326 // Added for initialize_itable_for_klass to handle exceptions
327 static void classes_do(void f(Klass*, TRAPS), TRAPS);
328 // All classes, and their class loaders
329 static void classes_do(void f(Klass*, ClassLoaderData*));
330
331 static void placeholders_do(void f(Symbol*));
332
333 // Iterate over all methods in all klasses in dictionary
334 static void methods_do(void f(Method*));
335
336 // Garbage collection support
337
338 // This method applies "blk->do_oop" to all the pointers to "system"
339 // classes and loaders.
340 static void always_strong_oops_do(OopClosure* blk);
341 static void always_strong_classes_do(KlassClosure* closure);
342
343 // Unload (that is, break root links to) all unmarked classes and
344 // loaders. Returns "true" iff something was unloaded.
345 static bool do_unloading(BoolObjectClosure* is_alive, bool clean_alive = true);
346
347 // Used by DumpSharedSpaces only to remove classes that failed verification
348 static void remove_classes_in_error_state();
349
350 static int calculate_systemdictionary_size(int loadedclasses);
351
352 // Applies "f->do_oop" to all root oops in the system dictionary.
353 static void oops_do(OopClosure* f);
354 static void roots_oops_do(OopClosure* strong, OopClosure* weak);
355
356 // System loader lock
357 static oop system_loader_lock() { return _system_loader_lock_obj; }
358
359 protected:
360 // Extended Redefine classes support (tbi)
361 static void preloaded_classes_do(KlassClosure* f);
362 static void lazily_loaded_classes_do(KlassClosure* f);
363 public:
364 // Sharing support.
365 static void reorder_dictionary();
366 static void copy_buckets(char** top, char* end);
367 static void copy_table(char** top, char* end);
368 static void reverse();
369 static void set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
370 int number_of_entries);
371 // Printing
372 static void print(bool details = true);
373 static void print_shared(bool details = true);
374 static void print_class_statistics() PRODUCT_RETURN;
375 static void print_method_statistics() PRODUCT_RETURN;
376
377 // Number of contained klasses
378 // This is both fully loaded classes and classes in the process
379 // of being loaded
380 static int number_of_classes();
381
382 // Monotonically increasing counter which grows as classes are
383 // loaded or modifications such as hot-swapping or setting/removing
384 // of breakpoints are performed
385 static inline int number_of_modifications() { assert_locked_or_safepoint(Compile_lock); return _number_of_modifications; }
386 // Needed by evolution and breakpoint code
387 static inline void notice_modification() { assert_locked_or_safepoint(Compile_lock); ++_number_of_modifications; }
388
389 // Verification
390 static void verify();
391
392 #ifdef ASSERT
393 static bool is_internal_format(Symbol* class_name);
394 #endif
395
396 // Initialization
397 static void initialize(TRAPS);
398
399 // Fast access to commonly used classes (preloaded)
400 static Klass* check_klass(Klass* k) {
401 assert(k != NULL, "preloaded klass not initialized");
402 return k;
403 }
404
405 static Klass* check_klass_Pre( Klass* k) { return check_klass(k); }
406 static Klass* check_klass_Pre_JSR292(Klass* k) { return EnableInvokeDynamic ? check_klass(k) : k; }
407 static Klass* check_klass_Opt( Klass* k) { return k; }
408 static Klass* check_klass_Opt_Only_JDK15(Klass* k) {
409 assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only");
410 return k;
411 }
412 static Klass* check_klass_Opt_Only_JDK14NewRef(Klass* k) {
413 assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only");
414 // despite the optional loading, if you use this it must be present:
415 return check_klass(k);
416 }
417
418 static bool initialize_wk_klass(WKID id, int init_opt, TRAPS);
419 static void initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS);
420 static void initialize_wk_klasses_through(WKID end_id, WKID &start_id, TRAPS) {
421 int limit = (int)end_id + 1;
422 initialize_wk_klasses_until((WKID) limit, start_id, THREAD);
423 }
424
425 public:
426 #define WK_KLASS_DECLARE(name, symbol, option) \
427 static Klass* name() { return check_klass_##option(_well_known_klasses[WK_KLASS_ENUM_NAME(name)]); } \
428 static Klass** name##_addr() { \
429 return &SystemDictionary::_well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]; \
430 }
431 WK_KLASSES_DO(WK_KLASS_DECLARE);
432 #undef WK_KLASS_DECLARE
433
434 static Klass* well_known_klass(WKID id) {
435 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
436 return _well_known_klasses[id];
437 }
438
439 static Klass** well_known_klass_addr(WKID id) {
440 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
441 return &_well_known_klasses[id];
442 }
443
444 // Local definition for direct access to the private array:
445 #define WK_KLASS(name) _well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]
446
447 static Klass* box_klass(BasicType t) {
448 assert((uint)t < T_VOID+1, "range check");
449 return check_klass(_box_klasses[t]);
450 }
451 static BasicType box_klass_type(Klass* k); // inverse of box_klass
452
453 // methods returning lazily loaded klasses
454 // The corresponding method to load the class must be called before calling them.
455 static Klass* abstract_ownable_synchronizer_klass() { return check_klass(_abstract_ownable_synchronizer_klass); }
456
457 static void load_abstract_ownable_synchronizer_klass(TRAPS);
458
459 protected:
460 // Tells whether ClassLoader.loadClassInternal is present
461 static bool has_loadClassInternal() { return _has_loadClassInternal; }
462
463 // Returns the class loader data to be used when looking up/updating the
464 // system dictionary.
465 static ClassLoaderData *class_loader_data(Handle class_loader) {
466 return ClassLoaderData::class_loader_data(class_loader());
467 }
468
469 public:
470 // Tells whether ClassLoader.checkPackageAccess is present
471 static bool has_checkPackageAccess() { return _has_checkPackageAccess; }
472
473 static bool Parameter_klass_loaded() { return WK_KLASS(reflect_Parameter_klass) != NULL; }
474 static bool Class_klass_loaded() { return WK_KLASS(Class_klass) != NULL; }
475 static bool Cloneable_klass_loaded() { return WK_KLASS(Cloneable_klass) != NULL; }
476 static bool Object_klass_loaded() { return WK_KLASS(Object_klass) != NULL; }
477 static bool ClassLoader_klass_loaded() { return WK_KLASS(ClassLoader_klass) != NULL; }
478
479 // Returns default system loader
480 static oop java_system_loader();
481
482 // Compute the default system loader
483 static void compute_java_system_loader(TRAPS);
484
485 // Register a new class loader
486 static ClassLoaderData* register_loader(Handle class_loader, TRAPS);
487 protected:
488 // Mirrors for primitive classes (created eagerly)
489 static oop check_mirror(oop m) {
490 assert(m != NULL, "mirror not initialized");
491 return m;
492 }
493
494 public:
495 // Note: java_lang_Class::primitive_type is the inverse of java_mirror
496
497 // Check class loader constraints
498 static bool add_loader_constraint(Symbol* name, Handle loader1,
499 Handle loader2, TRAPS);
500 static Symbol* check_signature_loaders(Symbol* signature, Handle loader1,
501 Handle loader2, bool is_method, TRAPS);
502
503 // JSR 292
504 // find a java.lang.invoke.MethodHandle.invoke* method for a given signature
505 // (asks Java to compute it if necessary, except in a compiler thread)
506 static methodHandle find_method_handle_invoker(Symbol* name,
507 Symbol* signature,
508 KlassHandle accessing_klass,
509 Handle *appendix_result,
510 Handle *method_type_result,
511 TRAPS);
512 // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic)
513 // (does not ask Java, since this is a low-level intrinsic defined by the JVM)
514 static methodHandle find_method_handle_intrinsic(vmIntrinsics::ID iid,
515 Symbol* signature,
516 TRAPS);
517 // find a java.lang.invoke.MethodType object for a given signature
518 // (asks Java to compute it if necessary, except in a compiler thread)
519 static Handle find_method_handle_type(Symbol* signature,
520 KlassHandle accessing_klass,
521 TRAPS);
522
523 // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
524 static Handle link_method_handle_constant(KlassHandle caller,
525 int ref_kind, //e.g., JVM_REF_invokeVirtual
526 KlassHandle callee,
527 Symbol* name,
528 Symbol* signature,
529 TRAPS);
530
531 // ask Java to create a dynamic call site, while linking an invokedynamic op
532 static methodHandle find_dynamic_call_site_invoker(KlassHandle caller,
533 Handle bootstrap_method,
534 Symbol* name,
535 Symbol* type,
536 Handle *appendix_result,
537 Handle *method_type_result,
538 TRAPS);
539
540 // Utility for printing loader "name" as part of tracing constraints
541 static const char* loader_name(oop loader) {
542 return ((loader) == NULL ? "<bootloader>" :
543 InstanceKlass::cast((loader)->klass())->name()->as_C_string() );
544 }
545 static const char* loader_name(ClassLoaderData* loader_data) {
546 return (loader_data->class_loader() == NULL ? "<bootloader>" :
547 InstanceKlass::cast((loader_data->class_loader())->klass())->name()->as_C_string() );
548 }
549
550 // Record the error when the first attempt to resolve a reference from a constant
551 // pool entry to a class fails.
552 static void add_resolution_error(constantPoolHandle pool, int which, Symbol* error);
553 static void delete_resolution_error(ConstantPool* pool);
554 static Symbol* find_resolution_error(constantPoolHandle pool, int which);
555
556 protected:
557
558 enum Constants {
559 _loader_constraint_size = 107, // number of entries in constraint table
560 _resolution_error_size = 107, // number of entries in resolution error table
561 _invoke_method_size = 139, // number of entries in invoke method table
562 _nof_buckets = 1009, // number of buckets in hash table for placeholders
563 _old_default_sdsize = 1009, // backward compat for system dictionary size
564 _prime_array_size = 8, // array of primes for system dictionary size
565 _average_depth_goal = 3 // goal for lookup length
566 };
567
568
569 // Static variables
570
571 // hashtable sizes for system dictionary to allow growth
572 // prime numbers for system dictionary size
573 static int _sdgeneration;
574 static const int _primelist[_prime_array_size];
575
576 // Hashtable holding loaded classes.
577 static Dictionary* _dictionary;
578
579 // Hashtable holding placeholders for classes being loaded.
580 static PlaceholderTable* _placeholders;
581
582 // Hashtable holding classes from the shared archive.
583 static Dictionary* _shared_dictionary;
584
585 // Monotonically increasing counter which grows with
586 // _number_of_classes as well as hot-swapping and breakpoint setting
587 // and removal.
588 static int _number_of_modifications;
589
590 // Lock object for system class loader
591 static oop _system_loader_lock_obj;
592
593 // Constraints on class loaders
594 static LoaderConstraintTable* _loader_constraints;
595
596 // Resolution errors
597 static ResolutionErrorTable* _resolution_errors;
598
599 // Invoke methods (JSR 292)
600 static SymbolPropertyTable* _invoke_method_table;
601
602 public:
603 // for VM_CounterDecay iteration support
604 friend class CounterDecay;
605 static Klass* try_get_next_class();
606
607 protected:
608 static void validate_protection_domain(instanceKlassHandle klass,
609 Handle class_loader,
610 Handle protection_domain, TRAPS);
611
612 friend class VM_PopulateDumpSharedSpace;
613 friend class TraversePlaceholdersClosure;
614 static Dictionary* dictionary() { return _dictionary; }
615 static Dictionary* shared_dictionary() { return _shared_dictionary; }
616 static PlaceholderTable* placeholders() { return _placeholders; }
617 static LoaderConstraintTable* constraints() { return _loader_constraints; }
618 static ResolutionErrorTable* resolution_errors() { return _resolution_errors; }
619 static SymbolPropertyTable* invoke_method_table() { return _invoke_method_table; }
620
621 // Basic loading operations
622 static Klass* resolve_instance_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
623 static Klass* resolve_array_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
624 static instanceKlassHandle handle_parallel_super_load(Symbol* class_name, Symbol* supername, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS);
625 // Wait on SystemDictionary_lock; unlocks lockObject before
626 // waiting; relocks lockObject with correct recursion count
627 // after waiting, but before reentering SystemDictionary_lock
628 // to preserve lock order semantics.
629 static void double_lock_wait(Handle lockObject, TRAPS);
630 static void define_instance_class(instanceKlassHandle k, TRAPS);
631 static instanceKlassHandle find_or_define_instance_class(Symbol* class_name,
632 Handle class_loader,
633 instanceKlassHandle k, TRAPS);
634 static instanceKlassHandle load_shared_class(instanceKlassHandle ik,
635 Handle class_loader,
636 Handle protection_domain,
637 TRAPS);
638 static instanceKlassHandle load_instance_class(Symbol* class_name, Handle class_loader, TRAPS);
639 static Handle compute_loader_lock_object(Handle class_loader, TRAPS);
640 static void check_loader_lock_contention(Handle loader_lock, TRAPS);
641 static bool is_parallelCapable(Handle class_loader);
642 static bool is_parallelDefine(Handle class_loader);
643
644 public:
645 static instanceKlassHandle load_shared_class(Symbol* class_name,
646 Handle class_loader,
647 TRAPS);
648 static bool is_ext_class_loader(Handle class_loader);
649
650 protected:
651 static Klass* find_shared_class(Symbol* class_name);
652
653 // Setup link to hierarchy
654 static void add_to_hierarchy(instanceKlassHandle k, TRAPS);
655
656 // event based tracing
657 static void post_class_load_event(const Ticks& start_time, instanceKlassHandle k,
658 Handle initiating_loader);
659 // We pass in the hashtable index so we can calculate it outside of
660 // the SystemDictionary_lock.
661
662 // Basic find on loaded classes
663 static Klass* find_class(int index, unsigned int hash,
664 Symbol* name, ClassLoaderData* loader_data);
665 static Klass* find_class(Symbol* class_name, ClassLoaderData* loader_data);
666
667 // Basic find on classes in the midst of being loaded
668 static Symbol* find_placeholder(Symbol* name, ClassLoaderData* loader_data);
669
670 // Updating entry in dictionary
671 // Add a completely loaded class
672 static void add_klass(int index, Symbol* class_name,
673 ClassLoaderData* loader_data, KlassHandle obj);
674
675 // Add a placeholder for a class being loaded
676 static void add_placeholder(int index,
677 Symbol* class_name,
678 ClassLoaderData* loader_data);
679 static void remove_placeholder(int index,
680 Symbol* class_name,
681 ClassLoaderData* loader_data);
682
683 // Performs cleanups after resolve_super_or_fail. This typically needs
684 // to be called on failure.
685 // Won't throw, but can block.
686 static void resolution_cleanups(Symbol* class_name,
687 ClassLoaderData* loader_data,
688 TRAPS);
689
690 // Initialization
691 static void initialize_preloaded_classes(TRAPS);
692
693 // Class loader constraints
694 static void check_constraints(int index, unsigned int hash,
695 instanceKlassHandle k, Handle loader,
696 bool defining, TRAPS);
697 static void update_dictionary(int d_index, unsigned int d_hash,
698 int p_index, unsigned int p_hash,
699 instanceKlassHandle k, Handle loader,
700 TRAPS);
701
702 // Variables holding commonly used klasses (preloaded)
703 static Klass* _well_known_klasses[];
704
705 // Lazily loaded klasses
706 static Klass* volatile _abstract_ownable_synchronizer_klass;
707
708 // table of box klasses (int_klass, etc.)
709 static Klass* _box_klasses[T_VOID+1];
710
711 static oop _java_system_loader;
712
713 static bool _has_loadClassInternal;
714 static bool _has_checkPackageAccess;
715 };
716
717 #endif // SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP