1 /*
   2  * Copyright (c) 1997, 2018, 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.
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  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   // We pass in the hashtable index so we can calculate it outside of
 657   // the SystemDictionary_lock.
 658 
 659   // Basic find on loaded classes
 660   static Klass* find_class(int index, unsigned int hash,
 661                              Symbol* name, ClassLoaderData* loader_data);
 662   static Klass* find_class(Symbol* class_name, ClassLoaderData* loader_data);
 663 
 664   // Basic find on classes in the midst of being loaded
 665   static Symbol* find_placeholder(Symbol* name, ClassLoaderData* loader_data);
 666 
 667   // Updating entry in dictionary
 668   // Add a completely loaded class
 669   static void add_klass(int index, Symbol* class_name,
 670                         ClassLoaderData* loader_data, KlassHandle obj);
 671 
 672   // Add a placeholder for a class being loaded
 673   static void add_placeholder(int index,
 674                               Symbol* class_name,
 675                               ClassLoaderData* loader_data);
 676   static void remove_placeholder(int index,
 677                                  Symbol* class_name,
 678                                  ClassLoaderData* loader_data);
 679 
 680   // Performs cleanups after resolve_super_or_fail. This typically needs
 681   // to be called on failure.
 682   // Won't throw, but can block.
 683   static void resolution_cleanups(Symbol* class_name,
 684                                   ClassLoaderData* loader_data,
 685                                   TRAPS);
 686 
 687   // Initialization
 688   static void initialize_preloaded_classes(TRAPS);
 689 
 690   // Class loader constraints
 691   static void check_constraints(int index, unsigned int hash,
 692                                 instanceKlassHandle k, Handle loader,
 693                                 bool defining, TRAPS);
 694   static void update_dictionary(int d_index, unsigned int d_hash,
 695                                 int p_index, unsigned int p_hash,
 696                                 instanceKlassHandle k, Handle loader,
 697                                 TRAPS);
 698 
 699   // Variables holding commonly used klasses (preloaded)
 700   static Klass* _well_known_klasses[];
 701 
 702   // Lazily loaded klasses
 703   static Klass* volatile _abstract_ownable_synchronizer_klass;
 704 
 705   // table of box klasses (int_klass, etc.)
 706   static Klass* _box_klasses[T_VOID+1];
 707 
 708   static oop  _java_system_loader;
 709 
 710   static bool _has_loadClassInternal;
 711   static bool _has_checkPackageAccess;
 712 };
 713 
 714 #endif // SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP