1 /* 2 * Copyright (c) 1997, 2013, 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 #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 // The system dictionary stores all loaded classes and maps: 38 // 39 // [class name,class loader] -> class i.e. [Symbol*,oop] -> Klass* 40 // 41 // Classes are loaded lazily. The default VM class loader is 42 // represented as NULL. 43 44 // The underlying data structure is an open hash table with a fixed number 45 // of buckets. During loading the loader object is locked, (for the VM loader 46 // a private lock object is used). Class loading can thus be done concurrently, 47 // but only by different loaders. 48 // 49 // During loading a placeholder (name, loader) is temporarily placed in 50 // a side data structure, and is used to detect ClassCircularityErrors 51 // and to perform verification during GC. A GC can occur in the midst 52 // of class loading, as we call out to Java, have to take locks, etc. 53 // 54 // When class loading is finished, a new entry is added to the system 55 // dictionary and the place holder is removed. Note that the protection 56 // domain field of the system dictionary has not yet been filled in when 57 // the "real" system dictionary entry is created. 58 // 59 // Clients of this class who are interested in finding if a class has 60 // been completely loaded -- not classes in the process of being loaded -- 61 // can read the SystemDictionary unlocked. This is safe because 62 // - entries are only deleted at safepoints 63 // - readers cannot come to a safepoint while actively examining 64 // an entry (an entry cannot be deleted from under a reader) 65 // - entries must be fully formed before they are available to concurrent 66 // readers (we must ensure write ordering) 67 // 68 // Note that placeholders are deleted at any time, as they are removed 69 // when a class is completely loaded. Therefore, readers as well as writers 70 // of placeholders must hold the SystemDictionary_lock. 71 // 72 73 class Dictionary; 74 class PlaceholderTable; 75 class LoaderConstraintTable; 76 template <MEMFLAGS F> class HashtableBucket; 77 class ResolutionErrorTable; 78 class SymbolPropertyTable; 79 80 // Certain classes are preloaded, such as java.lang.Object and java.lang.String. 81 // They are all "well-known", in the sense that no class loader is allowed 82 // to provide a different definition. 83 // 84 // These klasses must all have names defined in vmSymbols. 85 86 #define WK_KLASS_ENUM_NAME(kname) kname##_knum 87 88 // Each well-known class has a short klass name (like object_klass), 89 // a vmSymbol name (like java_lang_Object), and a flag word 90 // that makes some minor distinctions, like whether the klass 91 // is preloaded, optional, release-specific, etc. 92 // The order of these definitions is significant; it is the order in which 93 // preloading is actually performed by initialize_preloaded_classes. 94 95 #define WK_KLASSES_DO(do_klass) \ 96 /* well-known classes */ \ 97 do_klass(Object_klass, java_lang_Object, Pre ) \ 98 do_klass(String_klass, java_lang_String, Pre ) \ 99 do_klass(Class_klass, java_lang_Class, Pre ) \ 100 do_klass(Cloneable_klass, java_lang_Cloneable, Pre ) \ 101 do_klass(ClassLoader_klass, java_lang_ClassLoader, Pre ) \ 102 do_klass(Serializable_klass, java_io_Serializable, Pre ) \ 103 do_klass(System_klass, java_lang_System, Pre ) \ 104 do_klass(Throwable_klass, java_lang_Throwable, Pre ) \ 105 do_klass(Error_klass, java_lang_Error, Pre ) \ 106 do_klass(ThreadDeath_klass, java_lang_ThreadDeath, Pre ) \ 107 do_klass(Exception_klass, java_lang_Exception, Pre ) \ 108 do_klass(RuntimeException_klass, java_lang_RuntimeException, Pre ) \ 109 do_klass(SecurityManager_klass, java_lang_SecurityManager, Pre ) \ 110 do_klass(ProtectionDomain_klass, java_security_ProtectionDomain, Pre ) \ 111 do_klass(AccessControlContext_klass, java_security_AccessControlContext, Pre ) \ 112 do_klass(ClassNotFoundException_klass, java_lang_ClassNotFoundException, Pre ) \ 113 do_klass(NoClassDefFoundError_klass, java_lang_NoClassDefFoundError, Pre ) \ 114 do_klass(LinkageError_klass, java_lang_LinkageError, Pre ) \ 115 do_klass(ClassCastException_klass, java_lang_ClassCastException, Pre ) \ 116 do_klass(ArrayStoreException_klass, java_lang_ArrayStoreException, Pre ) \ 117 do_klass(VirtualMachineError_klass, java_lang_VirtualMachineError, Pre ) \ 118 do_klass(OutOfMemoryError_klass, java_lang_OutOfMemoryError, Pre ) \ 119 do_klass(StackOverflowError_klass, java_lang_StackOverflowError, Pre ) \ 120 do_klass(IllegalMonitorStateException_klass, java_lang_IllegalMonitorStateException, Pre ) \ 121 do_klass(Reference_klass, java_lang_ref_Reference, Pre ) \ 122 \ 123 /* Preload ref klasses and set reference types */ \ 124 do_klass(SoftReference_klass, java_lang_ref_SoftReference, Pre ) \ 125 do_klass(WeakReference_klass, java_lang_ref_WeakReference, Pre ) \ 126 do_klass(FinalReference_klass, java_lang_ref_FinalReference, Pre ) \ 127 do_klass(PhantomReference_klass, java_lang_ref_PhantomReference, Pre ) \ 128 do_klass(Finalizer_klass, java_lang_ref_Finalizer, Pre ) \ 129 \ 130 do_klass(Thread_klass, java_lang_Thread, Pre ) \ 131 do_klass(ThreadGroup_klass, java_lang_ThreadGroup, Pre ) \ 132 do_klass(Properties_klass, java_util_Properties, Pre ) \ 133 do_klass(reflect_AccessibleObject_klass, java_lang_reflect_AccessibleObject, Pre ) \ 134 do_klass(reflect_Field_klass, java_lang_reflect_Field, Pre ) \ 135 do_klass(reflect_Parameter_klass, java_lang_reflect_Parameter, Opt ) \ 136 do_klass(reflect_Method_klass, java_lang_reflect_Method, Pre ) \ 137 do_klass(reflect_Constructor_klass, java_lang_reflect_Constructor, Pre ) \ 138 \ 139 /* NOTE: needed too early in bootstrapping process to have checks based on JDK version */ \ 140 /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \ 141 /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \ 142 do_klass(lambda_MagicLambdaImpl_klass, java_lang_invoke_MagicLambdaImpl, Opt ) \ 143 do_klass(reflect_MagicAccessorImpl_klass, sun_reflect_MagicAccessorImpl, Opt ) \ 144 do_klass(reflect_MethodAccessorImpl_klass, sun_reflect_MethodAccessorImpl, Opt_Only_JDK14NewRef) \ 145 do_klass(reflect_ConstructorAccessorImpl_klass, sun_reflect_ConstructorAccessorImpl, Opt_Only_JDK14NewRef) \ 146 do_klass(reflect_DelegatingClassLoader_klass, sun_reflect_DelegatingClassLoader, Opt ) \ 147 do_klass(reflect_ConstantPool_klass, sun_reflect_ConstantPool, Opt_Only_JDK15 ) \ 148 do_klass(reflect_UnsafeStaticFieldAccessorImpl_klass, sun_reflect_UnsafeStaticFieldAccessorImpl, Opt_Only_JDK15 ) \ 149 do_klass(reflect_CallerSensitive_klass, sun_reflect_CallerSensitive, Opt ) \ 150 \ 151 /* support for dynamic typing; it's OK if these are NULL in earlier JDKs */ \ 152 do_klass(MethodHandle_klass, java_lang_invoke_MethodHandle, Pre_JSR292 ) \ 153 do_klass(MemberName_klass, java_lang_invoke_MemberName, Pre_JSR292 ) \ 154 do_klass(MethodHandleNatives_klass, java_lang_invoke_MethodHandleNatives, Pre_JSR292 ) \ 155 do_klass(LambdaForm_klass, java_lang_invoke_LambdaForm, Opt ) \ 156 do_klass(MethodType_klass, java_lang_invoke_MethodType, Pre_JSR292 ) \ 157 do_klass(BootstrapMethodError_klass, java_lang_BootstrapMethodError, Pre_JSR292 ) \ 158 do_klass(CallSite_klass, java_lang_invoke_CallSite, Pre_JSR292 ) \ 159 do_klass(ConstantCallSite_klass, java_lang_invoke_ConstantCallSite, Pre_JSR292 ) \ 160 do_klass(MutableCallSite_klass, java_lang_invoke_MutableCallSite, Pre_JSR292 ) \ 161 do_klass(VolatileCallSite_klass, java_lang_invoke_VolatileCallSite, Pre_JSR292 ) \ 162 /* Note: MethodHandle must be first, and VolatileCallSite last in group */ \ 163 \ 164 do_klass(StringBuffer_klass, java_lang_StringBuffer, Pre ) \ 165 do_klass(StringBuilder_klass, java_lang_StringBuilder, Pre ) \ 166 \ 167 /* It's NULL in non-1.4 JDKs. */ \ 168 do_klass(StackTraceElement_klass, java_lang_StackTraceElement, Opt ) \ 169 /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \ 170 /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \ 171 do_klass(nio_Buffer_klass, java_nio_Buffer, Opt ) \ 172 \ 173 do_klass(PostVMInitHook_klass, sun_misc_PostVMInitHook, Opt ) \ 174 \ 175 /* Preload boxing klasses */ \ 176 do_klass(Boolean_klass, java_lang_Boolean, Pre ) \ 177 do_klass(Character_klass, java_lang_Character, Pre ) \ 178 do_klass(Float_klass, java_lang_Float, Pre ) \ 179 do_klass(Double_klass, java_lang_Double, Pre ) \ 180 do_klass(Byte_klass, java_lang_Byte, Pre ) \ 181 do_klass(Short_klass, java_lang_Short, Pre ) \ 182 do_klass(Integer_klass, java_lang_Integer, Pre ) \ 183 do_klass(Long_klass, java_lang_Long, Pre ) \ 184 /*end*/ 185 186 187 class SystemDictionary : AllStatic { 188 friend class VMStructs; 189 friend class SystemDictionaryHandles; 190 191 public: 192 enum WKID { 193 NO_WKID = 0, 194 195 #define WK_KLASS_ENUM(name, symbol, ignore_o) WK_KLASS_ENUM_NAME(name), WK_KLASS_ENUM_NAME(symbol) = WK_KLASS_ENUM_NAME(name), 196 WK_KLASSES_DO(WK_KLASS_ENUM) 197 #undef WK_KLASS_ENUM 198 199 WKID_LIMIT, 200 201 FIRST_WKID = NO_WKID + 1 202 }; 203 204 enum InitOption { 205 Pre, // preloaded; error if not present 206 Pre_JSR292, // preloaded if EnableInvokeDynamic 207 208 // Order is significant. Options before this point require resolve_or_fail. 209 // Options after this point will use resolve_or_null instead. 210 211 Opt, // preload tried; NULL if not present 212 Opt_Only_JDK14NewRef, // preload tried; use only with NewReflection 213 Opt_Only_JDK15, // preload tried; use only with JDK1.5+ 214 OPTION_LIMIT, 215 CEIL_LG_OPTION_LIMIT = 4 // OPTION_LIMIT <= (1<<CEIL_LG_OPTION_LIMIT) 216 }; 217 218 219 // Returns a class with a given class name and class loader. Loads the 220 // class if needed. If not found a NoClassDefFoundError or a 221 // ClassNotFoundException is thrown, depending on the value on the 222 // throw_error flag. For most uses the throw_error argument should be set 223 // to true. 224 225 static Klass* resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS); 226 // Convenient call for null loader and protection domain. 227 static Klass* resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS); 228 private: 229 // handle error translation for resolve_or_null results 230 static Klass* handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS); 231 232 public: 233 234 // Returns a class with a given class name and class loader. 235 // Loads the class if needed. If not found NULL is returned. 236 static Klass* resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS); 237 // Version with null loader and protection domain 238 static Klass* resolve_or_null(Symbol* class_name, TRAPS); 239 240 // Resolve a superclass or superinterface. Called from ClassFileParser, 241 // parse_interfaces, resolve_instance_class_or_null, load_shared_class 242 // "child_name" is the class whose super class or interface is being resolved. 243 static Klass* resolve_super_or_fail(Symbol* child_name, 244 Symbol* class_name, 245 Handle class_loader, 246 Handle protection_domain, 247 bool is_superclass, 248 TRAPS); 249 250 // Parse new stream. This won't update the system dictionary or 251 // class hierarchy, simply parse the stream. Used by JVMTI RedefineClasses. 252 static Klass* parse_stream(Symbol* class_name, 253 Handle class_loader, 254 Handle protection_domain, 255 ClassFileStream* st, 256 TRAPS) { 257 KlassHandle nullHandle; 258 return parse_stream(class_name, class_loader, protection_domain, st, nullHandle, NULL, THREAD); 259 } 260 static Klass* parse_stream(Symbol* class_name, 261 Handle class_loader, 262 Handle protection_domain, 263 ClassFileStream* st, 264 KlassHandle host_klass, 265 GrowableArray<Handle>* cp_patches, 266 TRAPS); 267 268 // Resolve from stream (called by jni_DefineClass and JVM_DefineClass) 269 static Klass* resolve_from_stream(Symbol* class_name, Handle class_loader, 270 Handle protection_domain, 271 ClassFileStream* st, bool verify, TRAPS); 272 273 // Lookup an already loaded class. If not found NULL is returned. 274 static Klass* find(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS); 275 276 // Lookup an already loaded instance or array class. 277 // Do not make any queries to class loaders; consult only the cache. 278 // If not found NULL is returned. 279 static Klass* find_instance_or_array_klass(Symbol* class_name, 280 Handle class_loader, 281 Handle protection_domain, 282 TRAPS); 283 284 // Lookup an instance or array class that has already been loaded 285 // either into the given class loader, or else into another class 286 // loader that is constrained (via loader constraints) to produce 287 // a consistent class. Do not take protection domains into account. 288 // Do not make any queries to class loaders; consult only the cache. 289 // Return NULL if the class is not found. 290 // 291 // This function is a strict superset of find_instance_or_array_klass. 292 // This function (the unchecked version) makes a conservative prediction 293 // of the result of the checked version, assuming successful lookup. 294 // If both functions return non-null, they must return the same value. 295 // Also, the unchecked version may sometimes be non-null where the 296 // checked version is null. This can occur in several ways: 297 // 1. No query has yet been made to the class loader. 298 // 2. The class loader was queried, but chose not to delegate. 299 // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain. 300 // 4. Loading was attempted, but there was a linkage error of some sort. 301 // In all of these cases, the loader constraints on this type are 302 // satisfied, and it is safe for classes in the given class loader 303 // to manipulate strongly-typed values of the found class, subject 304 // to local linkage and access checks. 305 static Klass* find_constrained_instance_or_array_klass(Symbol* class_name, 306 Handle class_loader, 307 TRAPS); 308 309 // Iterate over all klasses in dictionary 310 // Just the classes from defining class loaders 311 static void classes_do(void f(Klass*)); 312 // Added for initialize_itable_for_klass to handle exceptions 313 static void classes_do(void f(Klass*, TRAPS), TRAPS); 314 // All classes, and their class loaders 315 static void classes_do(void f(Klass*, ClassLoaderData*)); 316 // All classes, and their class loaders 317 // (added for helpers that use HandleMarks and ResourceMarks) 318 static void classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS); 319 // All entries in the placeholder table and their class loaders 320 static void placeholders_do(void f(Symbol*)); 321 322 // Iterate over all methods in all klasses in dictionary 323 static void methods_do(void f(Method*)); 324 325 // Garbage collection support 326 327 // This method applies "blk->do_oop" to all the pointers to "system" 328 // classes and loaders. 329 static void always_strong_oops_do(OopClosure* blk); 330 static void always_strong_classes_do(KlassClosure* closure); 331 332 // Unload (that is, break root links to) all unmarked classes and 333 // loaders. Returns "true" iff something was unloaded. 334 static bool do_unloading(BoolObjectClosure* is_alive); 335 336 static int calculate_systemdictionary_size(int loadedclasses); 337 338 // Applies "f->do_oop" to all root oops in the system dictionary. 339 static void oops_do(OopClosure* f); 340 341 // System loader lock 342 static oop system_loader_lock() { return _system_loader_lock_obj; } 343 344 private: 345 // Extended Redefine classes support (tbi) 346 static void preloaded_classes_do(KlassClosure* f); 347 static void lazily_loaded_classes_do(KlassClosure* f); 348 public: 349 // Sharing support. 350 static void reorder_dictionary(); 351 static void copy_buckets(char** top, char* end); 352 static void copy_table(char** top, char* end); 353 static void reverse(); 354 static void set_shared_dictionary(HashtableBucket<mtClass>* t, int length, 355 int number_of_entries); 356 // Printing 357 static void print() PRODUCT_RETURN; 358 static void print_class_statistics() PRODUCT_RETURN; 359 static void print_method_statistics() PRODUCT_RETURN; 360 361 // Number of contained klasses 362 // This is both fully loaded classes and classes in the process 363 // of being loaded 364 static int number_of_classes(); 365 366 // Monotonically increasing counter which grows as classes are 367 // loaded or modifications such as hot-swapping or setting/removing 368 // of breakpoints are performed 369 static inline int number_of_modifications() { assert_locked_or_safepoint(Compile_lock); return _number_of_modifications; } 370 // Needed by evolution and breakpoint code 371 static inline void notice_modification() { assert_locked_or_safepoint(Compile_lock); ++_number_of_modifications; } 372 373 // Verification 374 static void verify(); 375 376 #ifdef ASSERT 377 static bool is_internal_format(Symbol* class_name); 378 #endif 379 380 // Verify class is in dictionary 381 static void verify_obj_klass_present(Symbol* class_name, 382 ClassLoaderData* loader_data); 383 384 // Initialization 385 static void initialize(TRAPS); 386 387 // Fast access to commonly used classes (preloaded) 388 static Klass* check_klass(Klass* k) { 389 assert(k != NULL, "preloaded klass not initialized"); 390 return k; 391 } 392 393 static Klass* check_klass_Pre( Klass* k) { return check_klass(k); } 394 static Klass* check_klass_Pre_JSR292(Klass* k) { return EnableInvokeDynamic ? check_klass(k) : k; } 395 static Klass* check_klass_Opt( Klass* k) { return k; } 396 static Klass* check_klass_Opt_Only_JDK15(Klass* k) { 397 assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only"); 398 return k; 399 } 400 static Klass* check_klass_Opt_Only_JDK14NewRef(Klass* k) { 401 assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only"); 402 // despite the optional loading, if you use this it must be present: 403 return check_klass(k); 404 } 405 406 static bool initialize_wk_klass(WKID id, int init_opt, TRAPS); 407 static void initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS); 408 static void initialize_wk_klasses_through(WKID end_id, WKID &start_id, TRAPS) { 409 int limit = (int)end_id + 1; 410 initialize_wk_klasses_until((WKID) limit, start_id, THREAD); 411 } 412 413 public: 414 #define WK_KLASS_DECLARE(name, symbol, option) \ 415 static Klass* name() { return check_klass_##option(_well_known_klasses[WK_KLASS_ENUM_NAME(name)]); } \ 416 static Klass** name##_addr() { \ 417 return &SystemDictionary::_well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]; \ 418 } 419 WK_KLASSES_DO(WK_KLASS_DECLARE); 420 #undef WK_KLASS_DECLARE 421 422 static Klass* well_known_klass(WKID id) { 423 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 424 return _well_known_klasses[id]; 425 } 426 427 static Klass** well_known_klass_addr(WKID id) { 428 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); 429 return &_well_known_klasses[id]; 430 } 431 432 // Local definition for direct access to the private array: 433 #define WK_KLASS(name) _well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)] 434 435 static Klass* box_klass(BasicType t) { 436 assert((uint)t < T_VOID+1, "range check"); 437 return check_klass(_box_klasses[t]); 438 } 439 static BasicType box_klass_type(Klass* k); // inverse of box_klass 440 441 // methods returning lazily loaded klasses 442 // The corresponding method to load the class must be called before calling them. 443 static Klass* abstract_ownable_synchronizer_klass() { return check_klass(_abstract_ownable_synchronizer_klass); } 444 445 static void load_abstract_ownable_synchronizer_klass(TRAPS); 446 447 private: 448 // Tells whether ClassLoader.loadClassInternal is present 449 static bool has_loadClassInternal() { return _has_loadClassInternal; } 450 451 // Returns the class loader data to be used when looking up/updating the 452 // system dictionary. 453 static ClassLoaderData *class_loader_data(Handle class_loader) { 454 return ClassLoaderData::class_loader_data(class_loader()); 455 } 456 457 public: 458 // Tells whether ClassLoader.checkPackageAccess is present 459 static bool has_checkPackageAccess() { return _has_checkPackageAccess; } 460 461 static bool Parameter_klass_loaded() { return WK_KLASS(reflect_Parameter_klass) != NULL; } 462 static bool Class_klass_loaded() { return WK_KLASS(Class_klass) != NULL; } 463 static bool Cloneable_klass_loaded() { return WK_KLASS(Cloneable_klass) != NULL; } 464 static bool Object_klass_loaded() { return WK_KLASS(Object_klass) != NULL; } 465 static bool ClassLoader_klass_loaded() { return WK_KLASS(ClassLoader_klass) != NULL; } 466 467 // Returns default system loader 468 static oop java_system_loader(); 469 470 // Compute the default system loader 471 static void compute_java_system_loader(TRAPS); 472 473 // Register a new class loader 474 static ClassLoaderData* register_loader(Handle class_loader, TRAPS); 475 private: 476 // Mirrors for primitive classes (created eagerly) 477 static oop check_mirror(oop m) { 478 assert(m != NULL, "mirror not initialized"); 479 return m; 480 } 481 482 public: 483 // Note: java_lang_Class::primitive_type is the inverse of java_mirror 484 485 // Check class loader constraints 486 static bool add_loader_constraint(Symbol* name, Handle loader1, 487 Handle loader2, TRAPS); 488 static char* check_signature_loaders(Symbol* signature, Handle loader1, 489 Handle loader2, bool is_method, TRAPS); 490 491 // JSR 292 492 // find a java.lang.invoke.MethodHandle.invoke* method for a given signature 493 // (asks Java to compute it if necessary, except in a compiler thread) 494 static methodHandle find_method_handle_invoker(Symbol* name, 495 Symbol* signature, 496 KlassHandle accessing_klass, 497 Handle *appendix_result, 498 Handle *method_type_result, 499 TRAPS); 500 // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic) 501 // (does not ask Java, since this is a low-level intrinsic defined by the JVM) 502 static methodHandle find_method_handle_intrinsic(vmIntrinsics::ID iid, 503 Symbol* signature, 504 TRAPS); 505 // find a java.lang.invoke.MethodType object for a given signature 506 // (asks Java to compute it if necessary, except in a compiler thread) 507 static Handle find_method_handle_type(Symbol* signature, 508 KlassHandle accessing_klass, 509 TRAPS); 510 511 // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry 512 static Handle link_method_handle_constant(KlassHandle caller, 513 int ref_kind, //e.g., JVM_REF_invokeVirtual 514 KlassHandle callee, 515 Symbol* name, 516 Symbol* signature, 517 TRAPS); 518 519 // ask Java to create a dynamic call site, while linking an invokedynamic op 520 static methodHandle find_dynamic_call_site_invoker(KlassHandle caller, 521 Handle bootstrap_method, 522 Symbol* name, 523 Symbol* type, 524 Handle *appendix_result, 525 Handle *method_type_result, 526 TRAPS); 527 528 // Utility for printing loader "name" as part of tracing constraints 529 static const char* loader_name(oop loader) { 530 return ((loader) == NULL ? "<bootloader>" : 531 InstanceKlass::cast((loader)->klass())->name()->as_C_string() ); 532 } 533 static const char* loader_name(ClassLoaderData* loader_data) { 534 return (loader_data->class_loader() == NULL ? "<bootloader>" : 535 InstanceKlass::cast((loader_data->class_loader())->klass())->name()->as_C_string() ); 536 } 537 538 // Record the error when the first attempt to resolve a reference from a constant 539 // pool entry to a class fails. 540 static void add_resolution_error(constantPoolHandle pool, int which, Symbol* error); 541 static void delete_resolution_error(ConstantPool* pool); 542 static Symbol* find_resolution_error(constantPoolHandle pool, int which); 543 544 private: 545 546 enum Constants { 547 _loader_constraint_size = 107, // number of entries in constraint table 548 _resolution_error_size = 107, // number of entries in resolution error table 549 _invoke_method_size = 139, // number of entries in invoke method table 550 _nof_buckets = 1009, // number of buckets in hash table for placeholders 551 _old_default_sdsize = 1009, // backward compat for system dictionary size 552 _prime_array_size = 8, // array of primes for system dictionary size 553 _average_depth_goal = 3 // goal for lookup length 554 }; 555 556 557 // Static variables 558 559 // hashtable sizes for system dictionary to allow growth 560 // prime numbers for system dictionary size 561 static int _sdgeneration; 562 static const int _primelist[_prime_array_size]; 563 564 // Hashtable holding loaded classes. 565 static Dictionary* _dictionary; 566 567 // Hashtable holding placeholders for classes being loaded. 568 static PlaceholderTable* _placeholders; 569 570 // Hashtable holding classes from the shared archive. 571 static Dictionary* _shared_dictionary; 572 573 // Monotonically increasing counter which grows with 574 // _number_of_classes as well as hot-swapping and breakpoint setting 575 // and removal. 576 static int _number_of_modifications; 577 578 // Lock object for system class loader 579 static oop _system_loader_lock_obj; 580 581 // Constraints on class loaders 582 static LoaderConstraintTable* _loader_constraints; 583 584 // Resolution errors 585 static ResolutionErrorTable* _resolution_errors; 586 587 // Invoke methods (JSR 292) 588 static SymbolPropertyTable* _invoke_method_table; 589 590 public: 591 // for VM_CounterDecay iteration support 592 friend class CounterDecay; 593 static Klass* try_get_next_class(); 594 595 private: 596 static void validate_protection_domain(instanceKlassHandle klass, 597 Handle class_loader, 598 Handle protection_domain, TRAPS); 599 600 friend class VM_PopulateDumpSharedSpace; 601 friend class TraversePlaceholdersClosure; 602 static Dictionary* dictionary() { return _dictionary; } 603 static Dictionary* shared_dictionary() { return _shared_dictionary; } 604 static PlaceholderTable* placeholders() { return _placeholders; } 605 static LoaderConstraintTable* constraints() { return _loader_constraints; } 606 static ResolutionErrorTable* resolution_errors() { return _resolution_errors; } 607 static SymbolPropertyTable* invoke_method_table() { return _invoke_method_table; } 608 609 // Basic loading operations 610 static Klass* resolve_instance_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS); 611 static Klass* resolve_array_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS); 612 static instanceKlassHandle handle_parallel_super_load(Symbol* class_name, Symbol* supername, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS); 613 // Wait on SystemDictionary_lock; unlocks lockObject before 614 // waiting; relocks lockObject with correct recursion count 615 // after waiting, but before reentering SystemDictionary_lock 616 // to preserve lock order semantics. 617 static void double_lock_wait(Handle lockObject, TRAPS); 618 static void define_instance_class(instanceKlassHandle k, TRAPS); 619 static instanceKlassHandle find_or_define_instance_class(Symbol* class_name, 620 Handle class_loader, 621 instanceKlassHandle k, TRAPS); 622 static instanceKlassHandle load_shared_class(Symbol* class_name, 623 Handle class_loader, TRAPS); 624 static instanceKlassHandle load_shared_class(instanceKlassHandle ik, 625 Handle class_loader, TRAPS); 626 static void clean_up_shared_class(instanceKlassHandle ik, Handle class_loader, TRAPS); 627 static instanceKlassHandle load_instance_class(Symbol* class_name, Handle class_loader, TRAPS); 628 static Handle compute_loader_lock_object(Handle class_loader, TRAPS); 629 static void check_loader_lock_contention(Handle loader_lock, TRAPS); 630 static bool is_parallelCapable(Handle class_loader); 631 static bool is_parallelDefine(Handle class_loader); 632 633 public: 634 static bool is_ext_class_loader(Handle class_loader); 635 636 private: 637 static Klass* find_shared_class(Symbol* class_name); 638 639 // Setup link to hierarchy 640 static void add_to_hierarchy(instanceKlassHandle k, TRAPS); 641 642 // We pass in the hashtable index so we can calculate it outside of 643 // the SystemDictionary_lock. 644 645 // Basic find on loaded classes 646 static Klass* find_class(int index, unsigned int hash, 647 Symbol* name, ClassLoaderData* loader_data); 648 static Klass* find_class(Symbol* class_name, ClassLoaderData* loader_data); 649 650 // Basic find on classes in the midst of being loaded 651 static Symbol* find_placeholder(Symbol* name, ClassLoaderData* loader_data); 652 653 // Updating entry in dictionary 654 // Add a completely loaded class 655 static void add_klass(int index, Symbol* class_name, 656 ClassLoaderData* loader_data, KlassHandle obj); 657 658 // Add a placeholder for a class being loaded 659 static void add_placeholder(int index, 660 Symbol* class_name, 661 ClassLoaderData* loader_data); 662 static void remove_placeholder(int index, 663 Symbol* class_name, 664 ClassLoaderData* loader_data); 665 666 // Performs cleanups after resolve_super_or_fail. This typically needs 667 // to be called on failure. 668 // Won't throw, but can block. 669 static void resolution_cleanups(Symbol* class_name, 670 ClassLoaderData* loader_data, 671 TRAPS); 672 673 // Initialization 674 static void initialize_preloaded_classes(TRAPS); 675 676 // Class loader constraints 677 static void check_constraints(int index, unsigned int hash, 678 instanceKlassHandle k, Handle loader, 679 bool defining, TRAPS); 680 static void update_dictionary(int d_index, unsigned int d_hash, 681 int p_index, unsigned int p_hash, 682 instanceKlassHandle k, Handle loader, 683 TRAPS); 684 685 // Variables holding commonly used klasses (preloaded) 686 static Klass* _well_known_klasses[]; 687 688 // Lazily loaded klasses 689 static Klass* volatile _abstract_ownable_synchronizer_klass; 690 691 // table of box klasses (int_klass, etc.) 692 static Klass* _box_klasses[T_VOID+1]; 693 694 static oop _java_system_loader; 695 696 static bool _has_loadClassInternal; 697 static bool _has_checkPackageAccess; 698 }; 699 700 #endif // SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP