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 
 317   static void placeholders_do(void f(Symbol*));
 318 
 319   // Iterate over all methods in all klasses in dictionary
 320   static void methods_do(void f(Method*));
 321 
 322   // Garbage collection support
 323 
 324   // This method applies "blk->do_oop" to all the pointers to "system"
 325   // classes and loaders.
 326   static void always_strong_oops_do(OopClosure* blk);
 327   static void always_strong_classes_do(KlassClosure* closure);
 328 
 329   // Unload (that is, break root links to) all unmarked classes and
 330   // loaders.  Returns "true" iff something was unloaded.
 331   static bool do_unloading(BoolObjectClosure* is_alive);
 332 
 333   static int calculate_systemdictionary_size(int loadedclasses);
 334 
 335   // Applies "f->do_oop" to all root oops in the system dictionary.
 336   static void oops_do(OopClosure* f);
 337 
 338   // System loader lock
 339   static oop system_loader_lock()           { return _system_loader_lock_obj; }
 340 
 341 private:
 342   // Extended Redefine classes support (tbi)
 343   static void preloaded_classes_do(KlassClosure* f);
 344   static void lazily_loaded_classes_do(KlassClosure* f);
 345 public:
 346   // Sharing support.
 347   static void reorder_dictionary();
 348   static void copy_buckets(char** top, char* end);
 349   static void copy_table(char** top, char* end);
 350   static void reverse();
 351   static void set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
 352                                     int number_of_entries);
 353   // Printing
 354   static void print()                   PRODUCT_RETURN;
 355   static void print_class_statistics()  PRODUCT_RETURN;
 356   static void print_method_statistics() PRODUCT_RETURN;
 357 
 358   // Number of contained klasses
 359   // This is both fully loaded classes and classes in the process
 360   // of being loaded
 361   static int number_of_classes();
 362 
 363   // Monotonically increasing counter which grows as classes are
 364   // loaded or modifications such as hot-swapping or setting/removing
 365   // of breakpoints are performed
 366   static inline int number_of_modifications()     { assert_locked_or_safepoint(Compile_lock); return _number_of_modifications; }
 367   // Needed by evolution and breakpoint code
 368   static inline void notice_modification()        { assert_locked_or_safepoint(Compile_lock); ++_number_of_modifications;      }
 369 
 370   // Verification
 371   static void verify();
 372 
 373 #ifdef ASSERT
 374   static bool is_internal_format(Symbol* class_name);
 375 #endif
 376 
 377   // Verify class is in dictionary
 378   static void verify_obj_klass_present(Symbol* class_name,
 379                                        ClassLoaderData* loader_data);
 380 
 381   // Initialization
 382   static void initialize(TRAPS);
 383 
 384   // Fast access to commonly used classes (preloaded)
 385   static Klass* check_klass(Klass* k) {
 386     assert(k != NULL, "preloaded klass not initialized");
 387     return k;
 388   }
 389 
 390   static Klass* check_klass_Pre(       Klass* k) { return check_klass(k); }
 391   static Klass* check_klass_Pre_JSR292(Klass* k) { return EnableInvokeDynamic ? check_klass(k) : k; }
 392   static Klass* check_klass_Opt(       Klass* k) { return k; }
 393   static Klass* check_klass_Opt_Only_JDK15(Klass* k) {
 394     assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only");
 395     return k;
 396   }
 397   static Klass* check_klass_Opt_Only_JDK14NewRef(Klass* k) {
 398     assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only");
 399     // despite the optional loading, if you use this it must be present:
 400     return check_klass(k);
 401   }
 402 
 403   static bool initialize_wk_klass(WKID id, int init_opt, TRAPS);
 404   static void initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS);
 405   static void initialize_wk_klasses_through(WKID end_id, WKID &start_id, TRAPS) {
 406     int limit = (int)end_id + 1;
 407     initialize_wk_klasses_until((WKID) limit, start_id, THREAD);
 408   }
 409 
 410 public:
 411   #define WK_KLASS_DECLARE(name, symbol, option) \
 412     static Klass* name() { return check_klass_##option(_well_known_klasses[WK_KLASS_ENUM_NAME(name)]); } \
 413     static Klass** name##_addr() {                                                                       \
 414       return &SystemDictionary::_well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)];           \
 415     }
 416   WK_KLASSES_DO(WK_KLASS_DECLARE);
 417   #undef WK_KLASS_DECLARE
 418 
 419   static Klass* well_known_klass(WKID id) {
 420     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
 421     return _well_known_klasses[id];
 422   }
 423 
 424   static Klass** well_known_klass_addr(WKID id) {
 425     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
 426     return &_well_known_klasses[id];
 427   }
 428 
 429   // Local definition for direct access to the private array:
 430   #define WK_KLASS(name) _well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]
 431 
 432   static Klass* box_klass(BasicType t) {
 433     assert((uint)t < T_VOID+1, "range check");
 434     return check_klass(_box_klasses[t]);
 435   }
 436   static BasicType box_klass_type(Klass* k);  // inverse of box_klass
 437 
 438   // methods returning lazily loaded klasses
 439   // The corresponding method to load the class must be called before calling them.
 440   static Klass* abstract_ownable_synchronizer_klass() { return check_klass(_abstract_ownable_synchronizer_klass); }
 441 
 442   static void load_abstract_ownable_synchronizer_klass(TRAPS);
 443 
 444 private:
 445   // Tells whether ClassLoader.loadClassInternal is present
 446   static bool has_loadClassInternal()       { return _has_loadClassInternal; }
 447 
 448   // Returns the class loader data to be used when looking up/updating the
 449   // system dictionary.
 450   static ClassLoaderData *class_loader_data(Handle class_loader) {
 451     return ClassLoaderData::class_loader_data(class_loader());
 452   }
 453 
 454 public:
 455   // Tells whether ClassLoader.checkPackageAccess is present
 456   static bool has_checkPackageAccess()      { return _has_checkPackageAccess; }
 457 
 458   static bool Parameter_klass_loaded()      { return WK_KLASS(reflect_Parameter_klass) != NULL; }
 459   static bool Class_klass_loaded()          { return WK_KLASS(Class_klass) != NULL; }
 460   static bool Cloneable_klass_loaded()      { return WK_KLASS(Cloneable_klass) != NULL; }
 461   static bool Object_klass_loaded()         { return WK_KLASS(Object_klass) != NULL; }
 462   static bool ClassLoader_klass_loaded()    { return WK_KLASS(ClassLoader_klass) != NULL; }
 463 
 464   // Returns default system loader
 465   static oop java_system_loader();
 466 
 467   // Compute the default system loader
 468   static void compute_java_system_loader(TRAPS);
 469 
 470   // Register a new class loader
 471   static ClassLoaderData* register_loader(Handle class_loader, TRAPS);
 472 private:
 473   // Mirrors for primitive classes (created eagerly)
 474   static oop check_mirror(oop m) {
 475     assert(m != NULL, "mirror not initialized");
 476     return m;
 477   }
 478 
 479 public:
 480   // Note:  java_lang_Class::primitive_type is the inverse of java_mirror
 481 
 482   // Check class loader constraints
 483   static bool add_loader_constraint(Symbol* name, Handle loader1,
 484                                     Handle loader2, TRAPS);
 485   static Symbol* check_signature_loaders(Symbol* signature, Handle loader1,
 486                                          Handle loader2, bool is_method, TRAPS);
 487 
 488   // JSR 292
 489   // find a java.lang.invoke.MethodHandle.invoke* method for a given signature
 490   // (asks Java to compute it if necessary, except in a compiler thread)
 491   static methodHandle find_method_handle_invoker(Symbol* name,
 492                                                  Symbol* signature,
 493                                                  KlassHandle accessing_klass,
 494                                                  Handle *appendix_result,
 495                                                  Handle *method_type_result,
 496                                                  TRAPS);
 497   // for a given signature, find the internal MethodHandle method (linkTo* or invokeBasic)
 498   // (does not ask Java, since this is a low-level intrinsic defined by the JVM)
 499   static methodHandle find_method_handle_intrinsic(vmIntrinsics::ID iid,
 500                                                    Symbol* signature,
 501                                                    TRAPS);
 502   // find a java.lang.invoke.MethodType object for a given signature
 503   // (asks Java to compute it if necessary, except in a compiler thread)
 504   static Handle    find_method_handle_type(Symbol* signature,
 505                                            KlassHandle accessing_klass,
 506                                            TRAPS);
 507 
 508   // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
 509   static Handle    link_method_handle_constant(KlassHandle caller,
 510                                                int ref_kind, //e.g., JVM_REF_invokeVirtual
 511                                                KlassHandle callee,
 512                                                Symbol* name,
 513                                                Symbol* signature,
 514                                                TRAPS);
 515 
 516   // ask Java to create a dynamic call site, while linking an invokedynamic op
 517   static methodHandle find_dynamic_call_site_invoker(KlassHandle caller,
 518                                                      Handle bootstrap_method,
 519                                                      Symbol* name,
 520                                                      Symbol* type,
 521                                                      Handle *appendix_result,
 522                                                      Handle *method_type_result,
 523                                                      TRAPS);
 524 
 525   // Utility for printing loader "name" as part of tracing constraints
 526   static const char* loader_name(oop loader) {
 527     return ((loader) == NULL ? "<bootloader>" :
 528             InstanceKlass::cast((loader)->klass())->name()->as_C_string() );
 529   }
 530   static const char* loader_name(ClassLoaderData* loader_data) {
 531     return (loader_data->class_loader() == NULL ? "<bootloader>" :
 532             InstanceKlass::cast((loader_data->class_loader())->klass())->name()->as_C_string() );
 533   }
 534 
 535   // Record the error when the first attempt to resolve a reference from a constant
 536   // pool entry to a class fails.
 537   static void add_resolution_error(constantPoolHandle pool, int which, Symbol* error);
 538   static void delete_resolution_error(ConstantPool* pool);
 539   static Symbol* find_resolution_error(constantPoolHandle pool, int which);
 540 
 541  private:
 542 
 543   enum Constants {
 544     _loader_constraint_size = 107,                     // number of entries in constraint table
 545     _resolution_error_size  = 107,                     // number of entries in resolution error table
 546     _invoke_method_size     = 139,                     // number of entries in invoke method table
 547     _nof_buckets            = 1009,                    // number of buckets in hash table for placeholders
 548     _old_default_sdsize     = 1009,                    // backward compat for system dictionary size
 549     _prime_array_size       = 8,                       // array of primes for system dictionary size
 550     _average_depth_goal     = 3                        // goal for lookup length
 551   };
 552 
 553 
 554   // Static variables
 555 
 556   // hashtable sizes for system dictionary to allow growth
 557   // prime numbers for system dictionary size
 558   static int                     _sdgeneration;
 559   static const int               _primelist[_prime_array_size];
 560 
 561   // Hashtable holding loaded classes.
 562   static Dictionary*            _dictionary;
 563 
 564   // Hashtable holding placeholders for classes being loaded.
 565   static PlaceholderTable*       _placeholders;
 566 
 567   // Hashtable holding classes from the shared archive.
 568   static Dictionary*             _shared_dictionary;
 569 
 570   // Monotonically increasing counter which grows with
 571   // _number_of_classes as well as hot-swapping and breakpoint setting
 572   // and removal.
 573   static int                     _number_of_modifications;
 574 
 575   // Lock object for system class loader
 576   static oop                     _system_loader_lock_obj;
 577 
 578   // Constraints on class loaders
 579   static LoaderConstraintTable*  _loader_constraints;
 580 
 581   // Resolution errors
 582   static ResolutionErrorTable*   _resolution_errors;
 583 
 584   // Invoke methods (JSR 292)
 585   static SymbolPropertyTable*    _invoke_method_table;
 586 
 587 public:
 588   // for VM_CounterDecay iteration support
 589   friend class CounterDecay;
 590   static Klass* try_get_next_class();
 591 
 592 private:
 593   static void validate_protection_domain(instanceKlassHandle klass,
 594                                          Handle class_loader,
 595                                          Handle protection_domain, TRAPS);
 596 
 597   friend class VM_PopulateDumpSharedSpace;
 598   friend class TraversePlaceholdersClosure;
 599   static Dictionary*         dictionary() { return _dictionary; }
 600   static Dictionary*         shared_dictionary() { return _shared_dictionary; }
 601   static PlaceholderTable*   placeholders() { return _placeholders; }
 602   static LoaderConstraintTable* constraints() { return _loader_constraints; }
 603   static ResolutionErrorTable* resolution_errors() { return _resolution_errors; }
 604   static SymbolPropertyTable* invoke_method_table() { return _invoke_method_table; }
 605 
 606   // Basic loading operations
 607   static Klass* resolve_instance_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
 608   static Klass* resolve_array_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
 609   static instanceKlassHandle handle_parallel_super_load(Symbol* class_name, Symbol* supername, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS);
 610   // Wait on SystemDictionary_lock; unlocks lockObject before
 611   // waiting; relocks lockObject with correct recursion count
 612   // after waiting, but before reentering SystemDictionary_lock
 613   // to preserve lock order semantics.
 614   static void double_lock_wait(Handle lockObject, TRAPS);
 615   static void define_instance_class(instanceKlassHandle k, TRAPS);
 616   static instanceKlassHandle find_or_define_instance_class(Symbol* class_name,
 617                                                 Handle class_loader,
 618                                                 instanceKlassHandle k, TRAPS);
 619   static instanceKlassHandle load_shared_class(Symbol* class_name,
 620                                                Handle class_loader, TRAPS);
 621   static instanceKlassHandle load_shared_class(instanceKlassHandle ik,
 622                                                Handle class_loader, TRAPS);
 623   static void clean_up_shared_class(instanceKlassHandle ik, Handle class_loader, TRAPS);
 624   static instanceKlassHandle load_instance_class(Symbol* class_name, Handle class_loader, TRAPS);
 625   static Handle compute_loader_lock_object(Handle class_loader, TRAPS);
 626   static void check_loader_lock_contention(Handle loader_lock, TRAPS);
 627   static bool is_parallelCapable(Handle class_loader);
 628   static bool is_parallelDefine(Handle class_loader);
 629 
 630 public:
 631   static bool is_ext_class_loader(Handle class_loader);
 632 
 633 private:
 634   static Klass* find_shared_class(Symbol* class_name);
 635 
 636   // Setup link to hierarchy
 637   static void add_to_hierarchy(instanceKlassHandle k, TRAPS);
 638 
 639   // We pass in the hashtable index so we can calculate it outside of
 640   // the SystemDictionary_lock.
 641 
 642   // Basic find on loaded classes
 643   static Klass* find_class(int index, unsigned int hash,
 644                              Symbol* name, ClassLoaderData* loader_data);
 645   static Klass* find_class(Symbol* class_name, ClassLoaderData* loader_data);
 646 
 647   // Basic find on classes in the midst of being loaded
 648   static Symbol* find_placeholder(Symbol* name, ClassLoaderData* loader_data);
 649 
 650   // Updating entry in dictionary
 651   // Add a completely loaded class
 652   static void add_klass(int index, Symbol* class_name,
 653                         ClassLoaderData* loader_data, KlassHandle obj);
 654 
 655   // Add a placeholder for a class being loaded
 656   static void add_placeholder(int index,
 657                               Symbol* class_name,
 658                               ClassLoaderData* loader_data);
 659   static void remove_placeholder(int index,
 660                                  Symbol* class_name,
 661                                  ClassLoaderData* loader_data);
 662 
 663   // Performs cleanups after resolve_super_or_fail. This typically needs
 664   // to be called on failure.
 665   // Won't throw, but can block.
 666   static void resolution_cleanups(Symbol* class_name,
 667                                   ClassLoaderData* loader_data,
 668                                   TRAPS);
 669 
 670   // Initialization
 671   static void initialize_preloaded_classes(TRAPS);
 672 
 673   // Class loader constraints
 674   static void check_constraints(int index, unsigned int hash,
 675                                 instanceKlassHandle k, Handle loader,
 676                                 bool defining, TRAPS);
 677   static void update_dictionary(int d_index, unsigned int d_hash,
 678                                 int p_index, unsigned int p_hash,
 679                                 instanceKlassHandle k, Handle loader,
 680                                 TRAPS);
 681 
 682   // Variables holding commonly used klasses (preloaded)
 683   static Klass* _well_known_klasses[];
 684 
 685   // Lazily loaded klasses
 686   static Klass* volatile _abstract_ownable_synchronizer_klass;
 687 
 688   // table of box klasses (int_klass, etc.)
 689   static Klass* _box_klasses[T_VOID+1];
 690 
 691   static oop  _java_system_loader;
 692 
 693   static bool _has_loadClassInternal;
 694   static bool _has_checkPackageAccess;
 695 };
 696 
 697 #endif // SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP