src/share/vm/classfile/systemDictionary.hpp

Wed, 04 Jul 2012 15:55:45 -0400

author
coleenp
date
Wed, 04 Jul 2012 15:55:45 -0400
changeset 3904
ace99a6ffc83
parent 3900
d2a62e0f25eb
child 3969
1d7922586cf6
permissions
-rw-r--r--

7181200: JVM new hashing code breaks SA in product mode
Summary: Made new_hash() overloaded rather than a virtual function so SA code doesn't need to be changed.
Reviewed-by: kvn, acorn, dholmes, fparain

     1 /*
     2  * Copyright (c) 1997, 2012, 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  */
    25 #ifndef SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP
    26 #define SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP
    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"
    37 // The system dictionary stores all loaded classes and maps:
    38 //
    39 //   [class name,class loader] -> class   i.e.  [Symbol*,oop] -> klassOop
    40 //
    41 // Classes are loaded lazily. The default VM class loader is
    42 // represented as NULL.
    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 //
    73 class Dictionary;
    74 class PlaceholderTable;
    75 class LoaderConstraintTable;
    76 template <MEMFLAGS F> class HashtableBucket;
    77 class ResolutionErrorTable;
    78 class SymbolPropertyTable;
    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.
    86 #define WK_KLASS_ENUM_NAME(kname)    kname##_knum
    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.
    95 #define WK_KLASSES_DO(template)                                               \
    96   /* well-known classes */                                                    \
    97   template(Object_klass,                 java_lang_Object,               Pre) \
    98   template(String_klass,                 java_lang_String,               Pre) \
    99   template(Class_klass,                  java_lang_Class,                Pre) \
   100   template(Cloneable_klass,              java_lang_Cloneable,            Pre) \
   101   template(ClassLoader_klass,            java_lang_ClassLoader,          Pre) \
   102   template(Serializable_klass,           java_io_Serializable,           Pre) \
   103   template(System_klass,                 java_lang_System,               Pre) \
   104   template(Throwable_klass,              java_lang_Throwable,            Pre) \
   105   template(Error_klass,                  java_lang_Error,                Pre) \
   106   template(ThreadDeath_klass,            java_lang_ThreadDeath,          Pre) \
   107   template(Exception_klass,              java_lang_Exception,            Pre) \
   108   template(RuntimeException_klass,       java_lang_RuntimeException,     Pre) \
   109   template(ProtectionDomain_klass,       java_security_ProtectionDomain, Pre) \
   110   template(AccessControlContext_klass,   java_security_AccessControlContext, Pre) \
   111   template(ClassNotFoundException_klass, java_lang_ClassNotFoundException, Pre) \
   112   template(NoClassDefFoundError_klass,   java_lang_NoClassDefFoundError, Pre) \
   113   template(LinkageError_klass,           java_lang_LinkageError,         Pre) \
   114   template(ClassCastException_klass,     java_lang_ClassCastException,   Pre) \
   115   template(ArrayStoreException_klass,    java_lang_ArrayStoreException,  Pre) \
   116   template(VirtualMachineError_klass,    java_lang_VirtualMachineError,  Pre) \
   117   template(OutOfMemoryError_klass,       java_lang_OutOfMemoryError,     Pre) \
   118   template(StackOverflowError_klass,     java_lang_StackOverflowError,   Pre) \
   119   template(IllegalMonitorStateException_klass, java_lang_IllegalMonitorStateException, Pre) \
   120   template(Reference_klass,              java_lang_ref_Reference,        Pre) \
   121                                                                               \
   122   /* Preload ref klasses and set reference types */                           \
   123   template(SoftReference_klass,          java_lang_ref_SoftReference,    Pre) \
   124   template(WeakReference_klass,          java_lang_ref_WeakReference,    Pre) \
   125   template(FinalReference_klass,         java_lang_ref_FinalReference,   Pre) \
   126   template(PhantomReference_klass,       java_lang_ref_PhantomReference, Pre) \
   127   template(Finalizer_klass,              java_lang_ref_Finalizer,        Pre) \
   128                                                                               \
   129   template(Thread_klass,                 java_lang_Thread,               Pre) \
   130   template(ThreadGroup_klass,            java_lang_ThreadGroup,          Pre) \
   131   template(Properties_klass,             java_util_Properties,           Pre) \
   132   template(reflect_AccessibleObject_klass, java_lang_reflect_AccessibleObject, Pre) \
   133   template(reflect_Field_klass,          java_lang_reflect_Field,        Pre) \
   134   template(reflect_Method_klass,         java_lang_reflect_Method,       Pre) \
   135   template(reflect_Constructor_klass,    java_lang_reflect_Constructor,  Pre) \
   136                                                                               \
   137   /* NOTE: needed too early in bootstrapping process to have checks based on JDK version */                              \
   138   /* Universe::is_gte_jdk14x_version() is not set up by this point. */                                                   \
   139   /* It's okay if this turns out to be NULL in non-1.4 JDKs. */                                                          \
   140   template(reflect_MagicAccessorImpl_klass,             sun_reflect_MagicAccessorImpl,             Opt)                  \
   141   template(reflect_MethodAccessorImpl_klass,            sun_reflect_MethodAccessorImpl,            Opt_Only_JDK14NewRef) \
   142   template(reflect_ConstructorAccessorImpl_klass,       sun_reflect_ConstructorAccessorImpl,       Opt_Only_JDK14NewRef) \
   143   template(reflect_DelegatingClassLoader_klass,         sun_reflect_DelegatingClassLoader,         Opt)                  \
   144   template(reflect_ConstantPool_klass,                  sun_reflect_ConstantPool,                  Opt_Only_JDK15)       \
   145   template(reflect_UnsafeStaticFieldAccessorImpl_klass, sun_reflect_UnsafeStaticFieldAccessorImpl, Opt_Only_JDK15)       \
   146                                                                               \
   147   /* support for dynamic typing; it's OK if these are NULL in earlier JDKs */ \
   148   template(MethodHandle_klass,             java_lang_invoke_MethodHandle,             Pre_JSR292) \
   149   template(MemberName_klass,               java_lang_invoke_MemberName,               Pre_JSR292) \
   150   template(MethodHandleNatives_klass,      java_lang_invoke_MethodHandleNatives,      Pre_JSR292) \
   151   template(AdapterMethodHandle_klass,      java_lang_invoke_AdapterMethodHandle,      Pre_JSR292) \
   152   template(BoundMethodHandle_klass,        java_lang_invoke_BoundMethodHandle,        Pre_JSR292) \
   153   template(DirectMethodHandle_klass,       java_lang_invoke_DirectMethodHandle,       Pre_JSR292) \
   154   template(MethodType_klass,               java_lang_invoke_MethodType,               Pre_JSR292) \
   155   template(MethodTypeForm_klass,           java_lang_invoke_MethodTypeForm,           Pre_JSR292) \
   156   template(BootstrapMethodError_klass,     java_lang_BootstrapMethodError,            Pre_JSR292) \
   157   template(WrongMethodTypeException_klass, java_lang_invoke_WrongMethodTypeException, Pre_JSR292) \
   158   template(CallSite_klass,                 java_lang_invoke_CallSite,                 Pre_JSR292) \
   159   template(CountingMethodHandle_klass,     java_lang_invoke_CountingMethodHandle,     Opt)        \
   160   template(ConstantCallSite_klass,         java_lang_invoke_ConstantCallSite,         Pre_JSR292) \
   161   template(MutableCallSite_klass,          java_lang_invoke_MutableCallSite,          Pre_JSR292) \
   162   template(VolatileCallSite_klass,         java_lang_invoke_VolatileCallSite,         Pre_JSR292) \
   163   /* Note: MethodHandle must be first, and VolatileCallSite last in group */  \
   164                                                                               \
   165   template(StringBuffer_klass,           java_lang_StringBuffer,         Pre) \
   166   template(StringBuilder_klass,          java_lang_StringBuilder,        Pre) \
   167                                                                               \
   168   /* It's NULL in non-1.4 JDKs. */                                            \
   169   template(StackTraceElement_klass,      java_lang_StackTraceElement,    Opt) \
   170   /* Universe::is_gte_jdk14x_version() is not set up by this point. */        \
   171   /* It's okay if this turns out to be NULL in non-1.4 JDKs. */               \
   172   template(nio_Buffer_klass,             java_nio_Buffer,                Opt) \
   173                                                                               \
   174   template(DownloadManager_klass,        sun_jkernel_DownloadManager, Opt_Kernel) \
   175                                                                               \
   176   template(PostVMInitHook_klass,         sun_misc_PostVMInitHook, Opt)        \
   177                                                                               \
   178   /* Preload boxing klasses */                                                \
   179   template(Boolean_klass,                java_lang_Boolean,              Pre) \
   180   template(Character_klass,              java_lang_Character,            Pre) \
   181   template(Float_klass,                  java_lang_Float,                Pre) \
   182   template(Double_klass,                 java_lang_Double,               Pre) \
   183   template(Byte_klass,                   java_lang_Byte,                 Pre) \
   184   template(Short_klass,                  java_lang_Short,                Pre) \
   185   template(Integer_klass,                java_lang_Integer,              Pre) \
   186   template(Long_klass,                   java_lang_Long,                 Pre) \
   187   /*end*/
   190 class SystemDictionary : AllStatic {
   191   friend class VMStructs;
   192   friend class CompactingPermGenGen;
   193   friend class SystemDictionaryHandles;
   194   NOT_PRODUCT(friend class instanceKlassKlass;)
   196  public:
   197   enum WKID {
   198     NO_WKID = 0,
   200     #define WK_KLASS_ENUM(name, symbol, ignore_o) WK_KLASS_ENUM_NAME(name), WK_KLASS_ENUM_NAME(symbol) = WK_KLASS_ENUM_NAME(name),
   201     WK_KLASSES_DO(WK_KLASS_ENUM)
   202     #undef WK_KLASS_ENUM
   204     WKID_LIMIT,
   206     FIRST_WKID = NO_WKID + 1
   207   };
   209   enum InitOption {
   210     Pre,                        // preloaded; error if not present
   211     Pre_JSR292,                 // preloaded if EnableInvokeDynamic
   213     // Order is significant.  Options before this point require resolve_or_fail.
   214     // Options after this point will use resolve_or_null instead.
   216     Opt,                        // preload tried; NULL if not present
   217     Opt_Only_JDK14NewRef,       // preload tried; use only with NewReflection
   218     Opt_Only_JDK15,             // preload tried; use only with JDK1.5+
   219     Opt_Kernel,                 // preload tried only #ifdef KERNEL
   220     OPTION_LIMIT,
   221     CEIL_LG_OPTION_LIMIT = 4    // OPTION_LIMIT <= (1<<CEIL_LG_OPTION_LIMIT)
   222   };
   225   // Returns a class with a given class name and class loader.  Loads the
   226   // class if needed. If not found a NoClassDefFoundError or a
   227   // ClassNotFoundException is thrown, depending on the value on the
   228   // throw_error flag.  For most uses the throw_error argument should be set
   229   // to true.
   231   static klassOop resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS);
   232   // Convenient call for null loader and protection domain.
   233   static klassOop resolve_or_fail(Symbol* class_name, bool throw_error, TRAPS);
   234 private:
   235   // handle error translation for resolve_or_null results
   236   static klassOop handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS);
   238 public:
   240   // Returns a class with a given class name and class loader.
   241   // Loads the class if needed. If not found NULL is returned.
   242   static klassOop resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
   243   // Version with null loader and protection domain
   244   static klassOop resolve_or_null(Symbol* class_name, TRAPS);
   246   // Resolve a superclass or superinterface. Called from ClassFileParser,
   247   // parse_interfaces, resolve_instance_class_or_null, load_shared_class
   248   // "child_name" is the class whose super class or interface is being resolved.
   249   static klassOop resolve_super_or_fail(Symbol* child_name,
   250                                         Symbol* class_name,
   251                                         Handle class_loader,
   252                                         Handle protection_domain,
   253                                         bool is_superclass,
   254                                         TRAPS);
   256   // Parse new stream. This won't update the system dictionary or
   257   // class hierarchy, simply parse the stream. Used by JVMTI RedefineClasses.
   258   static klassOop parse_stream(Symbol* class_name,
   259                                Handle class_loader,
   260                                Handle protection_domain,
   261                                ClassFileStream* st,
   262                                TRAPS) {
   263     KlassHandle nullHandle;
   264     return parse_stream(class_name, class_loader, protection_domain, st, nullHandle, NULL, THREAD);
   265   }
   266   static klassOop parse_stream(Symbol* class_name,
   267                                Handle class_loader,
   268                                Handle protection_domain,
   269                                ClassFileStream* st,
   270                                KlassHandle host_klass,
   271                                GrowableArray<Handle>* cp_patches,
   272                                TRAPS);
   274   // Resolve from stream (called by jni_DefineClass and JVM_DefineClass)
   275   static klassOop resolve_from_stream(Symbol* class_name, Handle class_loader,
   276                                       Handle protection_domain,
   277                                       ClassFileStream* st, bool verify, TRAPS);
   279   // Lookup an already loaded class. If not found NULL is returned.
   280   static klassOop find(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
   282   // Lookup an already loaded instance or array class.
   283   // Do not make any queries to class loaders; consult only the cache.
   284   // If not found NULL is returned.
   285   static klassOop find_instance_or_array_klass(Symbol* class_name,
   286                                                Handle class_loader,
   287                                                Handle protection_domain,
   288                                                TRAPS);
   290   // If the given name is known to vmSymbols, return the well-know klass:
   291   static klassOop find_well_known_klass(Symbol* class_name);
   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 klassOop find_constrained_instance_or_array_klass(Symbol* class_name,
   315                                                            Handle class_loader,
   316                                                            TRAPS);
   318   // Iterate over all klasses in dictionary
   319   //   Just the classes from defining class loaders
   320   static void classes_do(void f(klassOop));
   321   // Added for initialize_itable_for_klass to handle exceptions
   322   static void classes_do(void f(klassOop, TRAPS), TRAPS);
   323   //   All classes, and their class loaders
   324   static void classes_do(void f(klassOop, oop));
   325   //   All classes, and their class loaders
   326   //   (added for helpers that use HandleMarks and ResourceMarks)
   327   static void classes_do(void f(klassOop, oop, TRAPS), TRAPS);
   328   // All entries in the placeholder table and their class loaders
   329   static void placeholders_do(void f(Symbol*, oop));
   331   // Iterate over all methods in all klasses in dictionary
   332   static void methods_do(void f(methodOop));
   334   // Garbage collection support
   336   // This method applies "blk->do_oop" to all the pointers to "system"
   337   // classes and loaders.
   338   static void always_strong_oops_do(OopClosure* blk);
   339   static void always_strong_classes_do(OopClosure* blk);
   340   // This method applies "blk->do_oop" to all the placeholders.
   341   static void placeholders_do(OopClosure* blk);
   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);
   347   static int calculate_systemdictionary_size(int loadedclasses);
   349   // Applies "f->do_oop" to all root oops in the system dictionary.
   350   static void oops_do(OopClosure* f);
   352   // System loader lock
   353   static oop system_loader_lock()           { return _system_loader_lock_obj; }
   355 private:
   356   //    Traverses preloaded oops: various system classes.  These are
   357   //    guaranteed to be in the perm gen.
   358   static void preloaded_oops_do(OopClosure* f);
   359   static void lazily_loaded_oops_do(OopClosure* f);
   361 public:
   362   // Sharing support.
   363   static void reorder_dictionary();
   364   static void copy_buckets(char** top, char* end);
   365   static void copy_table(char** top, char* end);
   366   static void reverse();
   367   static void set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
   368                                     int number_of_entries);
   369   // Printing
   370   static void print()                   PRODUCT_RETURN;
   371   static void print_class_statistics()  PRODUCT_RETURN;
   372   static void print_method_statistics() PRODUCT_RETURN;
   374   // Number of contained klasses
   375   // This is both fully loaded classes and classes in the process
   376   // of being loaded
   377   static int number_of_classes();
   379   // Monotonically increasing counter which grows as classes are
   380   // loaded or modifications such as hot-swapping or setting/removing
   381   // of breakpoints are performed
   382   static inline int number_of_modifications()     { assert_locked_or_safepoint(Compile_lock); return _number_of_modifications; }
   383   // Needed by evolution and breakpoint code
   384   static inline void notice_modification()        { assert_locked_or_safepoint(Compile_lock); ++_number_of_modifications;      }
   386   // Verification
   387   static void verify();
   389 #ifdef ASSERT
   390   static bool is_internal_format(Symbol* class_name);
   391 #endif
   393   // Verify class is in dictionary
   394   static void verify_obj_klass_present(Handle obj,
   395                                        Symbol* class_name,
   396                                        Handle class_loader);
   398   // Initialization
   399   static void initialize(TRAPS);
   401   // Fast access to commonly used classes (preloaded)
   402   static klassOop check_klass(klassOop k) {
   403     assert(k != NULL, "preloaded klass not initialized");
   404     return k;
   405   }
   407   static klassOop check_klass_Pre(klassOop k) { return check_klass(k); }
   408   static klassOop check_klass_Pre_JSR292(klassOop k) { return EnableInvokeDynamic ? check_klass(k) : k; }
   409   static klassOop check_klass_Opt(klassOop k) { return k; }
   410   static klassOop check_klass_Opt_Kernel(klassOop k) { return k; } //== Opt
   411   static klassOop check_klass_Opt_Only_JDK15(klassOop k) {
   412     assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only");
   413     return k;
   414   }
   415   static klassOop check_klass_Opt_Only_JDK14NewRef(klassOop k) {
   416     assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only");
   417     // despite the optional loading, if you use this it must be present:
   418     return check_klass(k);
   419   }
   421   static bool initialize_wk_klass(WKID id, int init_opt, TRAPS);
   422   static void initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS);
   423   static void initialize_wk_klasses_through(WKID end_id, WKID &start_id, TRAPS) {
   424     int limit = (int)end_id + 1;
   425     initialize_wk_klasses_until((WKID) limit, start_id, THREAD);
   426   }
   428 public:
   429   #define WK_KLASS_DECLARE(name, symbol, option) \
   430     static klassOop name() { return check_klass_##option(_well_known_klasses[WK_KLASS_ENUM_NAME(name)]); }
   431   WK_KLASSES_DO(WK_KLASS_DECLARE);
   432   #undef WK_KLASS_DECLARE
   434   static klassOop well_known_klass(WKID id) {
   435     assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
   436     return _well_known_klasses[id];
   437   }
   439   // Local definition for direct access to the private array:
   440   #define WK_KLASS(name) _well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]
   442   static klassOop box_klass(BasicType t) {
   443     assert((uint)t < T_VOID+1, "range check");
   444     return check_klass(_box_klasses[t]);
   445   }
   446   static BasicType box_klass_type(klassOop k);  // inverse of box_klass
   448   // methods returning lazily loaded klasses
   449   // The corresponding method to load the class must be called before calling them.
   450   static klassOop abstract_ownable_synchronizer_klass() { return check_klass(_abstract_ownable_synchronizer_klass); }
   452   static void load_abstract_ownable_synchronizer_klass(TRAPS);
   454 private:
   455   // Tells whether ClassLoader.loadClassInternal is present
   456   static bool has_loadClassInternal()       { return _has_loadClassInternal; }
   458 public:
   459   // Tells whether ClassLoader.checkPackageAccess is present
   460   static bool has_checkPackageAccess()      { return _has_checkPackageAccess; }
   462   static bool Class_klass_loaded()          { return WK_KLASS(Class_klass) != NULL; }
   463   static bool Cloneable_klass_loaded()      { return WK_KLASS(Cloneable_klass) != NULL; }
   465   // Returns default system loader
   466   static oop java_system_loader();
   468   // Compute the default system loader
   469   static void compute_java_system_loader(TRAPS);
   471 private:
   472   // Mirrors for primitive classes (created eagerly)
   473   static oop check_mirror(oop m) {
   474     assert(m != NULL, "mirror not initialized");
   475     return m;
   476   }
   478 public:
   479   // Note:  java_lang_Class::primitive_type is the inverse of java_mirror
   481   // Check class loader constraints
   482   static bool add_loader_constraint(Symbol* name, Handle loader1,
   483                                     Handle loader2, TRAPS);
   484   static char* check_signature_loaders(Symbol* signature, Handle loader1,
   485                                        Handle loader2, bool is_method, TRAPS);
   487   // JSR 292
   488   // find the java.lang.invoke.MethodHandles::invoke method for a given signature
   489   static methodOop find_method_handle_invoke(Symbol* name,
   490                                              Symbol* signature,
   491                                              KlassHandle accessing_klass,
   492                                              TRAPS);
   493   // ask Java to compute a java.lang.invoke.MethodType object for a given signature
   494   static Handle    find_method_handle_type(Symbol* signature,
   495                                            KlassHandle accessing_klass,
   496                                            bool for_invokeGeneric,
   497                                            bool& return_bcp_flag,
   498                                            TRAPS);
   499   // ask Java to compute a java.lang.invoke.MethodHandle object for a given CP entry
   500   static Handle    link_method_handle_constant(KlassHandle caller,
   501                                                int ref_kind, //e.g., JVM_REF_invokeVirtual
   502                                                KlassHandle callee,
   503                                                Symbol* name,
   504                                                Symbol* signature,
   505                                                TRAPS);
   506   // ask Java to create a dynamic call site, while linking an invokedynamic op
   507   static Handle    make_dynamic_call_site(Handle bootstrap_method,
   508                                           // Callee information:
   509                                           Symbol* name,
   510                                           methodHandle signature_invoker,
   511                                           Handle info,
   512                                           // Caller information:
   513                                           methodHandle caller_method,
   514                                           int caller_bci,
   515                                           TRAPS);
   517   // coordinate with Java about bootstrap methods
   518   static Handle    find_bootstrap_method(methodHandle caller_method,
   519                                          int caller_bci,  // N.B. must be an invokedynamic
   520                                          int cache_index, // must be corresponding main_entry
   521                                          Handle &argument_info_result, // static BSM arguments, if any
   522                                          TRAPS);
   524   // Utility for printing loader "name" as part of tracing constraints
   525   static const char* loader_name(oop loader) {
   526     return ((loader) == NULL ? "<bootloader>" :
   527             instanceKlass::cast((loader)->klass())->name()->as_C_string() );
   528   }
   530   // Record the error when the first attempt to resolve a reference from a constant
   531   // pool entry to a class fails.
   532   static void add_resolution_error(constantPoolHandle pool, int which, Symbol* error);
   533   static Symbol* find_resolution_error(constantPoolHandle pool, int which);
   535  private:
   537   enum Constants {
   538     _loader_constraint_size = 107,                     // number of entries in constraint table
   539     _resolution_error_size  = 107,                     // number of entries in resolution error table
   540     _invoke_method_size     = 139,                     // number of entries in invoke method table
   541     _nof_buckets            = 1009,                    // number of buckets in hash table for placeholders
   542     _old_default_sdsize     = 1009,                    // backward compat for system dictionary size
   543     _prime_array_size       = 8,                       // array of primes for system dictionary size
   544     _average_depth_goal     = 3                        // goal for lookup length
   545   };
   548   // Static variables
   550   // hashtable sizes for system dictionary to allow growth
   551   // prime numbers for system dictionary size
   552   static int                     _sdgeneration;
   553   static const int               _primelist[_prime_array_size];
   555   // Hashtable holding loaded classes.
   556   static Dictionary*            _dictionary;
   558   // Hashtable holding placeholders for classes being loaded.
   559   static PlaceholderTable*       _placeholders;
   561   // Hashtable holding classes from the shared archive.
   562   static Dictionary*             _shared_dictionary;
   564   // Monotonically increasing counter which grows with
   565   // _number_of_classes as well as hot-swapping and breakpoint setting
   566   // and removal.
   567   static int                     _number_of_modifications;
   569   // Lock object for system class loader
   570   static oop                     _system_loader_lock_obj;
   572   // Constraints on class loaders
   573   static LoaderConstraintTable*  _loader_constraints;
   575   // Resolution errors
   576   static ResolutionErrorTable*   _resolution_errors;
   578   // Invoke methods (JSR 292)
   579   static SymbolPropertyTable*    _invoke_method_table;
   581 public:
   582   // for VM_CounterDecay iteration support
   583   friend class CounterDecay;
   584   static klassOop try_get_next_class();
   586 private:
   587   static void validate_protection_domain(instanceKlassHandle klass,
   588                                          Handle class_loader,
   589                                          Handle protection_domain, TRAPS);
   591   friend class VM_PopulateDumpSharedSpace;
   592   friend class TraversePlaceholdersClosure;
   593   static Dictionary*         dictionary() { return _dictionary; }
   594   static Dictionary*         shared_dictionary() { return _shared_dictionary; }
   595   static PlaceholderTable*   placeholders() { return _placeholders; }
   596   static LoaderConstraintTable* constraints() { return _loader_constraints; }
   597   static ResolutionErrorTable* resolution_errors() { return _resolution_errors; }
   598   static SymbolPropertyTable* invoke_method_table() { return _invoke_method_table; }
   600   // Basic loading operations
   601   static klassOop resolve_instance_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
   602   static klassOop resolve_array_class_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
   603   static instanceKlassHandle handle_parallel_super_load(Symbol* class_name, Symbol* supername, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS);
   604   // Wait on SystemDictionary_lock; unlocks lockObject before
   605   // waiting; relocks lockObject with correct recursion count
   606   // after waiting, but before reentering SystemDictionary_lock
   607   // to preserve lock order semantics.
   608   static void double_lock_wait(Handle lockObject, TRAPS);
   609   static void define_instance_class(instanceKlassHandle k, TRAPS);
   610   static instanceKlassHandle find_or_define_instance_class(Symbol* class_name,
   611                                                 Handle class_loader,
   612                                                 instanceKlassHandle k, TRAPS);
   613   static instanceKlassHandle load_shared_class(Symbol* class_name,
   614                                                Handle class_loader, TRAPS);
   615   static instanceKlassHandle load_shared_class(instanceKlassHandle ik,
   616                                                Handle class_loader, TRAPS);
   617   static instanceKlassHandle load_instance_class(Symbol* class_name, Handle class_loader, TRAPS);
   618   static Handle compute_loader_lock_object(Handle class_loader, TRAPS);
   619   static void check_loader_lock_contention(Handle loader_lock, TRAPS);
   620   static bool is_parallelCapable(Handle class_loader);
   621   static bool is_parallelDefine(Handle class_loader);
   623   static klassOop find_shared_class(Symbol* class_name);
   625   // Setup link to hierarchy
   626   static void add_to_hierarchy(instanceKlassHandle k, TRAPS);
   628 private:
   629   // We pass in the hashtable index so we can calculate it outside of
   630   // the SystemDictionary_lock.
   632   // Basic find on loaded classes
   633   static klassOop find_class(int index, unsigned int hash,
   634                              Symbol* name, Handle loader);
   635   static klassOop find_class(Symbol* class_name, Handle class_loader);
   637   // Basic find on classes in the midst of being loaded
   638   static Symbol* find_placeholder(Symbol* name, Handle loader);
   640   // Updating entry in dictionary
   641   // Add a completely loaded class
   642   static void add_klass(int index, Symbol* class_name,
   643                         Handle class_loader, KlassHandle obj);
   645   // Add a placeholder for a class being loaded
   646   static void add_placeholder(int index,
   647                               Symbol* class_name,
   648                               Handle class_loader);
   649   static void remove_placeholder(int index,
   650                                  Symbol* class_name,
   651                                  Handle class_loader);
   653   // Performs cleanups after resolve_super_or_fail. This typically needs
   654   // to be called on failure.
   655   // Won't throw, but can block.
   656   static void resolution_cleanups(Symbol* class_name,
   657                                   Handle class_loader,
   658                                   TRAPS);
   660   // Initialization
   661   static void initialize_preloaded_classes(TRAPS);
   663   // Class loader constraints
   664   static void check_constraints(int index, unsigned int hash,
   665                                 instanceKlassHandle k, Handle loader,
   666                                 bool defining, TRAPS);
   667   static void update_dictionary(int d_index, unsigned int d_hash,
   668                                 int p_index, unsigned int p_hash,
   669                                 instanceKlassHandle k, Handle loader, TRAPS);
   671   // Variables holding commonly used klasses (preloaded)
   672   static klassOop _well_known_klasses[];
   674   // Lazily loaded klasses
   675   static volatile klassOop _abstract_ownable_synchronizer_klass;
   677   // table of box klasses (int_klass, etc.)
   678   static klassOop _box_klasses[T_VOID+1];
   680   static oop  _java_system_loader;
   682   static bool _has_loadClassInternal;
   683   static bool _has_checkPackageAccess;
   684 };
   686 class SystemDictionaryHandles : AllStatic {
   687 public:
   688   #define WK_KLASS_HANDLE_DECLARE(name, ignore_symbol, option) \
   689     static KlassHandle name() { \
   690       SystemDictionary::name(); \
   691       klassOop* loc = &SystemDictionary::_well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]; \
   692       return KlassHandle(loc, true); \
   693     }
   694   WK_KLASSES_DO(WK_KLASS_HANDLE_DECLARE);
   695   #undef WK_KLASS_HANDLE_DECLARE
   697   static KlassHandle box_klass(BasicType t);
   698 };
   700 #endif // SHARE_VM_CLASSFILE_SYSTEMDICTIONARY_HPP

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