1 /*
   2  * Copyright (c) 1997, 2015, 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 
  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 class Ticks;
  81 
  82 // Certain classes are preloaded, such as java.lang.Object and java.lang.String.
  83 // They are all "well-known", in the sense that no class loader is allowed
  84 // to provide a different definition.
  85 //
  86 // These klasses must all have names defined in vmSymbols.
  87 
  88 #define WK_KLASS_ENUM_NAME(kname)    kname##_knum
  89 
  90 // Each well-known class has a short klass name (like object_klass),
  91 // a vmSymbol name (like java_lang_Object), and a flag word
  92 // that makes some minor distinctions, like whether the klass
  93 // is preloaded, optional, release-specific, etc.
  94 // The order of these definitions is significant; it is the order in which
  95 // preloading is actually performed by initialize_preloaded_classes.
  96 
  97 #define WK_KLASSES_DO(do_klass)                                                                                          \
  98   /* well-known classes */                                                                                               \
  99   do_klass(Object_klass,                                java_lang_Object,                          Pre                 ) \
 100   do_klass(String_klass,                                java_lang_String,                          Pre                 ) \
 101   do_klass(Class_klass,                                 java_lang_Class,                           Pre                 ) \
 102   do_klass(Cloneable_klass,                             java_lang_Cloneable,                       Pre                 ) \
 103   do_klass(ClassLoader_klass,                           java_lang_ClassLoader,                     Pre                 ) \
 104   do_klass(Serializable_klass,                          java_io_Serializable,                      Pre                 ) \
 105   do_klass(System_klass,                                java_lang_System,                          Pre                 ) \
 106   do_klass(Throwable_klass,                             java_lang_Throwable,                       Pre                 ) \
 107   do_klass(Error_klass,                                 java_lang_Error,                           Pre                 ) \
 108   do_klass(ThreadDeath_klass,                           java_lang_ThreadDeath,                     Pre                 ) \
 109   do_klass(Exception_klass,                             java_lang_Exception,                       Pre                 ) \
 110   do_klass(RuntimeException_klass,                      java_lang_RuntimeException,                Pre                 ) \
 111   do_klass(SecurityManager_klass,                       java_lang_SecurityManager,                 Pre                 ) \
 112   do_klass(ProtectionDomain_klass,                      java_security_ProtectionDomain,            Pre                 ) \
 113   do_klass(AccessControlContext_klass,                  java_security_AccessControlContext,        Pre                 ) \
 114   do_klass(SecureClassLoader_klass,                     java_security_SecureClassLoader,           Pre                 ) \
 115   do_klass(ClassNotFoundException_klass,                java_lang_ClassNotFoundException,          Pre                 ) \
 116   do_klass(NoClassDefFoundError_klass,                  java_lang_NoClassDefFoundError,            Pre                 ) \
 117   do_klass(LinkageError_klass,                          java_lang_LinkageError,                    Pre                 ) \
 118   do_klass(ClassCastException_klass,                    java_lang_ClassCastException,              Pre                 ) \
 119   do_klass(ArrayStoreException_klass,                   java_lang_ArrayStoreException,             Pre                 ) \
 120   do_klass(VirtualMachineError_klass,                   java_lang_VirtualMachineError,             Pre                 ) \
 121   do_klass(OutOfMemoryError_klass,                      java_lang_OutOfMemoryError,                Pre                 ) \
 122   do_klass(StackOverflowError_klass,                    java_lang_StackOverflowError,              Pre                 ) \
 123   do_klass(IllegalMonitorStateException_klass,          java_lang_IllegalMonitorStateException,    Pre                 ) \
 124   do_klass(Reference_klass,                             java_lang_ref_Reference,                   Pre                 ) \
 125                                                                                                                          \
 126   /* Preload ref klasses and set reference types */                                                                      \
 127   do_klass(SoftReference_klass,                         java_lang_ref_SoftReference,               Pre                 ) \
 128   do_klass(WeakReference_klass,                         java_lang_ref_WeakReference,               Pre                 ) \
 129   do_klass(FinalReference_klass,                        java_lang_ref_FinalReference,              Pre                 ) \
 130   do_klass(PhantomReference_klass,                      java_lang_ref_PhantomReference,            Pre                 ) \
 131   do_klass(Cleaner_klass,                               sun_misc_Cleaner,                          Pre                 ) \
 132   do_klass(Finalizer_klass,                             java_lang_ref_Finalizer,                   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_Module_klass,                        java_lang_reflect_Module,                  Pre                 ) \
 140   do_klass(reflect_Parameter_klass,                     java_lang_reflect_Parameter,               Opt                 ) \
 141   do_klass(reflect_Method_klass,                        java_lang_reflect_Method,                  Pre                 ) \
 142   do_klass(reflect_Constructor_klass,                   java_lang_reflect_Constructor,             Pre                 ) \
 143                                                                                                                          \
 144   /* NOTE: needed too early in bootstrapping process to have checks based on JDK version */                              \
 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,            Pre                 ) \
 148   do_klass(reflect_ConstructorAccessorImpl_klass,       sun_reflect_ConstructorAccessorImpl,       Pre                 ) \
 149   do_klass(reflect_DelegatingClassLoader_klass,         sun_reflect_DelegatingClassLoader,         Opt                 ) \
 150   do_klass(reflect_ConstantPool_klass,                  sun_reflect_ConstantPool,                  Opt                 ) \
 151   do_klass(reflect_UnsafeStaticFieldAccessorImpl_klass, sun_reflect_UnsafeStaticFieldAccessorImpl, Opt                 ) \
 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                 ) \
 157   do_klass(MemberName_klass,                            java_lang_invoke_MemberName,               Pre                 ) \
 158   do_klass(MethodHandleNatives_klass,                   java_lang_invoke_MethodHandleNatives,      Pre                 ) \
 159   do_klass(LambdaForm_klass,                            java_lang_invoke_LambdaForm,               Opt                 ) \
 160   do_klass(MethodType_klass,                            java_lang_invoke_MethodType,               Pre                 ) \
 161   do_klass(BootstrapMethodError_klass,                  java_lang_BootstrapMethodError,            Pre                 ) \
 162   do_klass(CallSite_klass,                              java_lang_invoke_CallSite,                 Pre                 ) \
 163   do_klass(Context_klass,                               java_lang_invoke_MethodHandleNatives_CallSiteContext, Pre      ) \
 164   do_klass(ConstantCallSite_klass,                      java_lang_invoke_ConstantCallSite,         Pre                 ) \
 165   do_klass(MutableCallSite_klass,                       java_lang_invoke_MutableCallSite,          Pre                 ) \
 166   do_klass(VolatileCallSite_klass,                      java_lang_invoke_VolatileCallSite,         Pre                 ) \
 167   /* Note: MethodHandle must be first, and VolatileCallSite last in group */                                             \
 168                                                                                                                          \
 169   do_klass(StringBuffer_klass,                          java_lang_StringBuffer,                    Pre                 ) \
 170   do_klass(StringBuilder_klass,                         java_lang_StringBuilder,                   Pre                 ) \
 171   do_klass(misc_Unsafe_klass,                           sun_misc_Unsafe,                           Pre                 ) \
 172                                                                                                                          \
 173   /* support for CDS */                                                                                                  \
 174   do_klass(ByteArrayInputStream_klass,                  java_io_ByteArrayInputStream,              Pre                 ) \
 175   do_klass(File_klass,                                  java_io_File,                              Pre                 ) \
 176   do_klass(URL_klass,                                   java_net_URL,                              Pre                 ) \
 177   do_klass(Jar_Manifest_klass,                          java_util_jar_Manifest,                    Pre                 ) \
 178   do_klass(jdk_internal_misc_ClassLoaders_AppClassLoader_klass,  jdk_internal_misc_ClassLoaders_AppClassLoader,      Pre                 ) \
 179   do_klass(CodeSource_klass,                            java_security_CodeSource,                  Pre                 ) \
 180   do_klass(ParseUtil_klass,                             sun_net_www_ParseUtil,                     Pre                 ) \
 181                                                                                                                          \
 182   /* It's NULL in non-1.4 JDKs. */                                                                                       \
 183   do_klass(StackTraceElement_klass,                     java_lang_StackTraceElement,               Opt                 ) \
 184   /* It's okay if this turns out to be NULL in non-1.4 JDKs. */                                                          \
 185   do_klass(nio_Buffer_klass,                            java_nio_Buffer,                           Opt                 ) \
 186                                                                                                                          \
 187   /* Preload boxing klasses */                                                                                           \
 188   do_klass(Boolean_klass,                               java_lang_Boolean,                         Pre                 ) \
 189   do_klass(Character_klass,                             java_lang_Character,                       Pre                 ) \
 190   do_klass(Float_klass,                                 java_lang_Float,                           Pre                 ) \
 191   do_klass(Double_klass,                                java_lang_Double,                          Pre                 ) \
 192   do_klass(Byte_klass,                                  java_lang_Byte,                            Pre                 ) \
 193   do_klass(Short_klass,                                 java_lang_Short,                           Pre                 ) \
 194   do_klass(Integer_klass,                               java_lang_Integer,                         Pre                 ) \
 195   do_klass(Long_klass,                                  java_lang_Long,                            Pre                 ) \
 196   /*end*/
 197 
 198 
 199 class SystemDictionary : AllStatic {
 200   friend class VMStructs;
 201   friend class SystemDictionaryHandles;
 202 
 203  public:
 204   enum WKID {
 205     NO_WKID = 0,
 206 
 207     #define WK_KLASS_ENUM(name, symbol, ignore_o) WK_KLASS_ENUM_NAME(name), WK_KLASS_ENUM_NAME(symbol) = WK_KLASS_ENUM_NAME(name),
 208     WK_KLASSES_DO(WK_KLASS_ENUM)
 209     #undef WK_KLASS_ENUM
 210 
 211     WKID_LIMIT,
 212 
 213     FIRST_WKID = NO_WKID + 1
 214   };
 215 
 216   enum InitOption {
 217     Pre,                        // preloaded; error if not present
 218 
 219     // Order is significant.  Options before this point require resolve_or_fail.
 220     // Options after this point will use resolve_or_null instead.
 221 
 222     Opt,                        // preload tried; NULL if not present
 223     OPTION_LIMIT,
 224     CEIL_LG_OPTION_LIMIT = 2    // OPTION_LIMIT <= (1<<CEIL_LG_OPTION_LIMIT)
 225   };
 226 
 227 
 228   // Returns a class with a given class name and class loader.  Loads the
 229   // class if needed. If not found a NoClassDefFoundError or a
 230   // ClassNotFoundException is thrown, depending on the value on the
 231   // throw_error flag.  For most uses the throw_error argument should be set
 232   // to true.
 233 
 234   static Klass* resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS);
 235   // Convenient call for null loader and protection domain.
 236   static Klass* resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS);
 237 protected:
 238   // handle error translation for resolve_or_null results
 239   static Klass* handle_resolution_exception(Symbol* class_name, bool throw_error, KlassHandle klass_h, TRAPS);
 240 
 241 public:
 242 
 243   // Returns a class with a given class name and class loader.
 244   // Loads the class if needed. If not found NULL is returned.
 245   static Klass* resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
 246   // Version with null loader and protection domain
 247   static Klass* resolve_or_null(Symbol* class_name, TRAPS);
 248 
 249   // Resolve a superclass or superinterface. Called from ClassFileParser,
 250   // parse_interfaces, resolve_instance_class_or_null, load_shared_class
 251   // "child_name" is the class whose super class or interface is being resolved.
 252   static Klass* resolve_super_or_fail(Symbol* child_name,
 253                                         Symbol* class_name,
 254                                         Handle class_loader,
 255                                         Handle protection_domain,
 256                                         bool is_superclass,
 257                                         TRAPS);
 258 
 259   // Parse new stream. This won't update the system dictionary or
 260   // class hierarchy, simply parse the stream. Used by JVMTI RedefineClasses.
 261   static Klass* parse_stream(Symbol* class_name,
 262                                Handle class_loader,
 263                                Handle protection_domain,
 264                                ClassFileStream* st,
 265                                TRAPS) {
 266     KlassHandle nullHandle;
 267     return parse_stream(class_name, class_loader, protection_domain, st, nullHandle, NULL, THREAD);
 268   }
 269   static Klass* parse_stream(Symbol* class_name,
 270                                Handle class_loader,
 271                                Handle protection_domain,
 272                                ClassFileStream* st,
 273                                KlassHandle host_klass,
 274                                GrowableArray<Handle>* cp_patches,
 275                                TRAPS);
 276 
 277   // Resolve from stream (called by jni_DefineClass and JVM_DefineClass)
 278   static Klass* resolve_from_stream(Symbol* class_name, Handle class_loader,
 279                                       Handle protection_domain,
 280                                       ClassFileStream* st, bool verify, TRAPS);
 281 
 282   // Lookup an already loaded class. If not found NULL is returned.
 283   static Klass* find(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
 284 
 285   // Lookup an already loaded instance or array class.
 286   // Do not make any queries to class loaders; consult only the cache.
 287   // If not found NULL is returned.
 288   static Klass* find_instance_or_array_klass(Symbol* class_name,
 289                                                Handle class_loader,
 290                                                Handle protection_domain,
 291                                                TRAPS);
 292 
 293   // Lookup an instance or array class that has already been loaded
 294   // either into the given class loader, or else into another class
 295   // loader that is constrained (via loader constraints) to produce
 296   // a consistent class.  Do not take protection domains into account.
 297   // Do not make any queries to class loaders; consult only the cache.
 298   // Return NULL if the class is not found.
 299   //
 300   // This function is a strict superset of find_instance_or_array_klass.
 301   // This function (the unchecked version) makes a conservative prediction
 302   // of the result of the checked version, assuming successful lookup.
 303   // If both functions return non-null, they must return the same value.
 304   // Also, the unchecked version may sometimes be non-null where the
 305   // checked version is null.  This can occur in several ways:
 306   //   1. No query has yet been made to the class loader.
 307   //   2. The class loader was queried, but chose not to delegate.
 308   //   3. ClassLoader.checkPackageAccess rejected a proposed protection domain.
 309   //   4. Loading was attempted, but there was a linkage error of some sort.
 310   // In all of these cases, the loader constraints on this type are
 311   // satisfied, and it is safe for classes in the given class loader
 312   // to manipulate strongly-typed values of the found class, subject
 313   // to local linkage and access checks.
 314   static Klass* find_constrained_instance_or_array_klass(Symbol* class_name,
 315                                                            Handle class_loader,
 316                                                            TRAPS);
 317 
 318   // Iterate over all klasses in dictionary
 319   //   Just the classes from defining class loaders
 320   static void classes_do(void f(Klass*));
 321   // Added for initialize_itable_for_klass to handle exceptions
 322   static void classes_do(void f(Klass*, TRAPS), TRAPS);
 323   //   All classes, and their class loaders
 324   static void classes_do(void f(Klass*, ClassLoaderData*));
 325 
 326   static void placeholders_do(void f(Symbol*));
 327 
 328   // Iterate over all methods in all klasses in dictionary
 329   static void methods_do(void f(Method*));
 330 
 331   // Garbage collection support
 332 
 333   // This method applies "blk->do_oop" to all the pointers to "system"
 334   // classes and loaders.
 335   static void always_strong_oops_do(OopClosure* blk);
 336   static void always_strong_classes_do(KlassClosure* closure);
 337 
 338   // Unload (that is, break root links to) all unmarked classes and
 339   // loaders.  Returns "true" iff something was unloaded.
 340   static bool do_unloading(BoolObjectClosure* is_alive,
 341                            bool clean_previous_versions = true);
 342 
 343   // Used by DumpSharedSpaces only to remove classes that failed verification
 344   static void remove_classes_in_error_state();
 345 
 346   static int calculate_systemdictionary_size(int loadedclasses);
 347 
 348   // Applies "f->do_oop" to all root oops in the system dictionary.
 349   static void oops_do(OopClosure* f);
 350   static void roots_oops_do(OopClosure* strong, OopClosure* weak);
 351 
 352   // System loader lock
 353   static oop system_loader_lock()           { return _system_loader_lock_obj; }
 354 
 355 protected:
 356   // Extended Redefine classes support (tbi)
 357   static void preloaded_classes_do(KlassClosure* f);
 358   static void lazily_loaded_classes_do(KlassClosure* f);
 359 public:
 360   // Sharing support.
 361   static void reorder_dictionary();
 362   static void copy_buckets(char** top, char* end);
 363   static void copy_table(char** top, char* end);
 364   static void reverse();
 365   static void set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
 366                                     int number_of_entries);
 367   // Printing
 368   static void print(bool details = true);
 369   static void print_shared(bool details = true);
 370   static void print_class_statistics()  PRODUCT_RETURN;
 371   static void print_method_statistics() PRODUCT_RETURN;
 372 
 373   // Number of contained klasses
 374   // This is both fully loaded classes and classes in the process
 375   // of being loaded
 376   static int number_of_classes();
 377 
 378   // Monotonically increasing counter which grows as classes are
 379   // loaded or modifications such as hot-swapping or setting/removing
 380   // of breakpoints are performed
 381   static inline int number_of_modifications()     { assert_locked_or_safepoint(Compile_lock); return _number_of_modifications; }
 382   // Needed by evolution and breakpoint code
 383   static inline void notice_modification()        { assert_locked_or_safepoint(Compile_lock); ++_number_of_modifications;      }
 384 
 385   // Verification
 386   static void verify();
 387 
 388 #ifdef ASSERT
 389   static bool is_internal_format(Symbol* class_name);
 390 #endif
 391 
 392   // Initialization
 393   static void initialize(TRAPS);
 394 
 395   // Fast access to commonly used classes (preloaded)
 396   static Klass* check_klass(Klass* k) {
 397     assert(k != NULL, "preloaded klass not initialized");
 398     return k;
 399   }
 400 
 401   static Klass* check_klass_Pre(       Klass* k) { return check_klass(k); }
 402   static Klass* check_klass_Opt(       Klass* k) { return k; }
 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, symbol, option) \
 413     static Klass* name() { return check_klass_##option(_well_known_klasses[WK_KLASS_ENUM_NAME(name)]); } \
 414     static Klass** name##_addr() {                                                                       \
 415       return &SystemDictionary::_well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)];           \
 416     }
 417   WK_KLASSES_DO(WK_KLASS_DECLARE);
 418   #undef WK_KLASS_DECLARE
 419 
 420   static Klass* well_known_klass(WKID id) {
 421     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
 422     return _well_known_klasses[id];
 423   }
 424 
 425   static Klass** well_known_klass_addr(WKID id) {
 426     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
 427     return &_well_known_klasses[id];
 428   }
 429 
 430   // Local definition for direct access to the private array:
 431   #define WK_KLASS(name) _well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]
 432 
 433   static Klass* box_klass(BasicType t) {
 434     assert((uint)t < T_VOID+1, "range check");
 435     return check_klass(_box_klasses[t]);
 436   }
 437   static BasicType box_klass_type(Klass* k);  // inverse of box_klass
 438 
 439   // methods returning lazily loaded klasses
 440   // The corresponding method to load the class must be called before calling them.
 441   static Klass* abstract_ownable_synchronizer_klass() { return check_klass(_abstract_ownable_synchronizer_klass); }
 442 
 443   static void load_abstract_ownable_synchronizer_klass(TRAPS);
 444 
 445 protected:
 446   // Tells whether ClassLoader.loadClassInternal is present
 447   static bool has_loadClassInternal()       { return _has_loadClassInternal; }
 448 
 449   // Returns the class loader data to be used when looking up/updating the
 450   // system dictionary.
 451   static ClassLoaderData *class_loader_data(Handle class_loader) {
 452     return ClassLoaderData::class_loader_data(class_loader());
 453   }
 454 
 455 public:
 456   // Tells whether ClassLoader.checkPackageAccess is present
 457   static bool has_checkPackageAccess()      { return _has_checkPackageAccess; }
 458 
 459   static bool Parameter_klass_loaded()      { return WK_KLASS(reflect_Parameter_klass) != NULL; }
 460   static bool Class_klass_loaded()          { return WK_KLASS(Class_klass) != NULL; }
 461   static bool Cloneable_klass_loaded()      { return WK_KLASS(Cloneable_klass) != NULL; }
 462   static bool Object_klass_loaded()         { return WK_KLASS(Object_klass) != NULL; }
 463   static bool ClassLoader_klass_loaded()    { return WK_KLASS(ClassLoader_klass) != NULL; }
 464 
 465   // Returns default system loader
 466   static oop java_system_loader();
 467 
 468   // Compute the default system loader
 469   static void compute_java_system_loader(TRAPS);
 470 
 471   // Register a new class loader
 472   static ClassLoaderData* register_loader(Handle class_loader, TRAPS);
 473 protected:
 474   // Mirrors for primitive classes (created eagerly)
 475   static oop check_mirror(oop m) {
 476     assert(m != NULL, "mirror not initialized");
 477     return m;
 478   }
 479 
 480 public:
 481   // Note:  java_lang_Class::primitive_type is the inverse of java_mirror
 482 
 483   // Check class loader constraints
 484   static bool add_loader_constraint(Symbol* name, Handle loader1,
 485                                     Handle loader2, TRAPS);
 486   static Symbol* check_signature_loaders(Symbol* signature, Handle loader1,
 487                                          Handle loader2, bool is_method, TRAPS);
 488 
 489   // JSR 292
 490   // find a java.lang.invoke.MethodHandle.invoke* method for a given signature
 491   // (asks Java to compute it if necessary, except in a compiler thread)
 492   static methodHandle find_method_handle_invoker(Symbol* name,
 493                                                  Symbol* signature,
 494                                                  KlassHandle accessing_klass,
 495                                                  Handle *appendix_result,
 496                                                  Handle *method_type_result,
 497                                                  TRAPS);
 498   // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic)
 499   // (does not ask Java, since this is a low-level intrinsic defined by the JVM)
 500   static methodHandle find_method_handle_intrinsic(vmIntrinsics::ID iid,
 501                                                    Symbol* signature,
 502                                                    TRAPS);
 503   // find a java.lang.invoke.MethodType object for a given signature
 504   // (asks Java to compute it if necessary, except in a compiler thread)
 505   static Handle    find_method_handle_type(Symbol* signature,
 506                                            KlassHandle accessing_klass,
 507                                            TRAPS);
 508 
 509   // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
 510   static Handle    link_method_handle_constant(KlassHandle caller,
 511                                                int ref_kind, //e.g., JVM_REF_invokeVirtual
 512                                                KlassHandle callee,
 513                                                Symbol* name,
 514                                                Symbol* signature,
 515                                                TRAPS);
 516 
 517   // ask Java to create a dynamic call site, while linking an invokedynamic op
 518   static methodHandle find_dynamic_call_site_invoker(KlassHandle caller,
 519                                                      Handle bootstrap_method,
 520                                                      Symbol* name,
 521                                                      Symbol* type,
 522                                                      Handle *appendix_result,
 523                                                      Handle *method_type_result,
 524                                                      TRAPS);
 525 
 526   // Utility for printing loader "name" as part of tracing constraints
 527   static const char* loader_name(oop loader) {
 528     return ((loader) == NULL ? "<bootloader>" :
 529             InstanceKlass::cast((loader)->klass())->name()->as_C_string() );
 530   }
 531   static const char* loader_name(ClassLoaderData* loader_data) {
 532     return (loader_data->class_loader() == NULL ? "<bootloader>" :
 533             InstanceKlass::cast((loader_data->class_loader())->klass())->name()->as_C_string() );
 534   }
 535 
 536   // Record the error when the first attempt to resolve a reference from a constant
 537   // pool entry to a class fails.
 538   static void add_resolution_error(constantPoolHandle pool, int which, Symbol* error,
 539                                    Symbol* message);
 540   static void delete_resolution_error(ConstantPool* pool);
 541   static Symbol* find_resolution_error(constantPoolHandle pool, int which,
 542                                        Symbol** message);
 543 
 544  protected:
 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 protected:
 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(instanceKlassHandle ik,
 623                                                Handle class_loader,
 624                                                Handle protection_domain,
 625                                                TRAPS);
 626   static instanceKlassHandle load_instance_class(Symbol* class_name, Handle class_loader, TRAPS);
 627   static Handle compute_loader_lock_object(Handle class_loader, TRAPS);
 628   static void check_loader_lock_contention(Handle loader_lock, TRAPS);
 629   static bool is_parallelCapable(Handle class_loader);
 630   static bool is_parallelDefine(Handle class_loader);
 631 
 632 public:
 633   static instanceKlassHandle load_shared_class(Symbol* class_name,
 634                                                Handle class_loader,
 635                                                TRAPS);
 636   static bool is_ext_class_loader(Handle class_loader);
 637 
 638 protected:
 639   static Klass* find_shared_class(Symbol* class_name);
 640 
 641   // Setup link to hierarchy
 642   static void add_to_hierarchy(instanceKlassHandle k, TRAPS);
 643 
 644   // event based tracing
 645   static void post_class_load_event(const Ticks& start_time, instanceKlassHandle k,
 646                                     Handle initiating_loader);
 647   // We pass in the hashtable index so we can calculate it outside of
 648   // the SystemDictionary_lock.
 649 
 650   // Basic find on loaded classes
 651   static Klass* find_class(int index, unsigned int hash,
 652                              Symbol* name, ClassLoaderData* loader_data);
 653   static Klass* find_class(Symbol* class_name, ClassLoaderData* loader_data);
 654 
 655   // Basic find on classes in the midst of being loaded
 656   static Symbol* find_placeholder(Symbol* name, ClassLoaderData* loader_data);
 657 
 658   // Updating entry in dictionary
 659   // Add a completely loaded class
 660   static void add_klass(int index, Symbol* class_name,
 661                         ClassLoaderData* loader_data, KlassHandle obj);
 662 
 663   // Add a placeholder for a class being loaded
 664   static void add_placeholder(int index,
 665                               Symbol* class_name,
 666                               ClassLoaderData* loader_data);
 667   static void remove_placeholder(int index,
 668                                  Symbol* class_name,
 669                                  ClassLoaderData* loader_data);
 670 
 671   // Performs cleanups after resolve_super_or_fail. This typically needs
 672   // to be called on failure.
 673   // Won't throw, but can block.
 674   static void resolution_cleanups(Symbol* class_name,
 675                                   ClassLoaderData* loader_data,
 676                                   TRAPS);
 677 
 678   // Initialization
 679   static void initialize_preloaded_classes(TRAPS);
 680 
 681   // Class loader constraints
 682   static void check_constraints(int index, unsigned int hash,
 683                                 instanceKlassHandle k, Handle loader,
 684                                 bool defining, TRAPS);
 685   static void update_dictionary(int d_index, unsigned int d_hash,
 686                                 int p_index, unsigned int p_hash,
 687                                 instanceKlassHandle k, Handle loader,
 688                                 TRAPS);
 689 
 690   // Variables holding commonly used klasses (preloaded)
 691   static Klass* _well_known_klasses[];
 692 
 693   // Lazily loaded klasses
 694   static Klass* volatile _abstract_ownable_synchronizer_klass;
 695 
 696   // table of box klasses (int_klass, etc.)
 697   static Klass* _box_klasses[T_VOID+1];
 698 
 699   static oop  _java_system_loader;
 700 
 701   static bool _has_loadClassInternal;
 702   static bool _has_checkPackageAccess;
 703 };
 704 
 705 #endif // SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP