/* * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ // The system dictionary stores all loaded classes and maps: // // [class name,class loader] -> class i.e. [symbolOop,oop] -> klassOop // // Classes are loaded lazily. The default VM class loader is // represented as NULL. // The underlying data structure is an open hash table with a fixed number // of buckets. During loading the loader object is locked, (for the VM loader // a private lock object is used). Class loading can thus be done concurrently, // but only by different loaders. // // During loading a placeholder (name, loader) is temporarily placed in // a side data structure, and is used to detect ClassCircularityErrors // and to perform verification during GC. A GC can occur in the midst // of class loading, as we call out to Java, have to take locks, etc. // // When class loading is finished, a new entry is added to the system // dictionary and the place holder is removed. Note that the protection // domain field of the system dictionary has not yet been filled in when // the "real" system dictionary entry is created. // // Clients of this class who are interested in finding if a class has // been completely loaded -- not classes in the process of being loaded -- // can read the SystemDictionary unlocked. This is safe because // - entries are only deleted at safepoints // - readers cannot come to a safepoint while actively examining // an entry (an entry cannot be deleted from under a reader) // - entries must be fully formed before they are available to concurrent // readers (we must ensure write ordering) // // Note that placeholders are deleted at any time, as they are removed // when a class is completely loaded. Therefore, readers as well as writers // of placeholders must hold the SystemDictionary_lock. // class Dictionary; class PlaceholderTable; class LoaderConstraintTable; class HashtableBucket; class ResolutionErrorTable; class SymbolPropertyTable; // Certain classes are preloaded, such as java.lang.Object and java.lang.String. // They are all "well-known", in the sense that no class loader is allowed // to provide a different definition. // // These klasses must all have names defined in vmSymbols. #define WK_KLASS_ENUM_NAME(kname) kname##_knum // Each well-known class has a short klass name (like object_klass), // a vmSymbol name (like java_lang_Object), and a flag word // that makes some minor distinctions, like whether the klass // is preloaded, optional, release-specific, etc. // The order of these definitions is significant; it is the order in which // preloading is actually performed by initialize_preloaded_classes. #define WK_KLASSES_DO(template) \ /* well-known classes */ \ template(object_klass, java_lang_Object, Pre) \ template(string_klass, java_lang_String, Pre) \ template(class_klass, java_lang_Class, Pre) \ template(cloneable_klass, java_lang_Cloneable, Pre) \ template(classloader_klass, java_lang_ClassLoader, Pre) \ template(serializable_klass, java_io_Serializable, Pre) \ template(system_klass, java_lang_System, Pre) \ template(throwable_klass, java_lang_Throwable, Pre) \ template(error_klass, java_lang_Error, Pre) \ template(threaddeath_klass, java_lang_ThreadDeath, Pre) \ template(exception_klass, java_lang_Exception, Pre) \ template(runtime_exception_klass, java_lang_RuntimeException, Pre) \ template(protectionDomain_klass, java_security_ProtectionDomain, Pre) \ template(AccessControlContext_klass, java_security_AccessControlContext, Pre) \ template(classNotFoundException_klass, java_lang_ClassNotFoundException, Pre) \ template(noClassDefFoundError_klass, java_lang_NoClassDefFoundError, Pre) \ template(linkageError_klass, java_lang_LinkageError, Pre) \ template(ClassCastException_klass, java_lang_ClassCastException, Pre) \ template(ArrayStoreException_klass, java_lang_ArrayStoreException, Pre) \ template(virtualMachineError_klass, java_lang_VirtualMachineError, Pre) \ template(OutOfMemoryError_klass, java_lang_OutOfMemoryError, Pre) \ template(StackOverflowError_klass, java_lang_StackOverflowError, Pre) \ template(IllegalMonitorStateException_klass, java_lang_IllegalMonitorStateException, Pre) \ template(reference_klass, java_lang_ref_Reference, Pre) \ \ /* Preload ref klasses and set reference types */ \ template(soft_reference_klass, java_lang_ref_SoftReference, Pre) \ template(weak_reference_klass, java_lang_ref_WeakReference, Pre) \ template(final_reference_klass, java_lang_ref_FinalReference, Pre) \ template(phantom_reference_klass, java_lang_ref_PhantomReference, Pre) \ template(finalizer_klass, java_lang_ref_Finalizer, Pre) \ \ template(thread_klass, java_lang_Thread, Pre) \ template(threadGroup_klass, java_lang_ThreadGroup, Pre) \ template(properties_klass, java_util_Properties, Pre) \ template(reflect_accessible_object_klass, java_lang_reflect_AccessibleObject, Pre) \ template(reflect_field_klass, java_lang_reflect_Field, Pre) \ template(reflect_method_klass, java_lang_reflect_Method, Pre) \ template(reflect_constructor_klass, java_lang_reflect_Constructor, Pre) \ \ /* NOTE: needed too early in bootstrapping process to have checks based on JDK version */ \ /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \ /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \ template(reflect_magic_klass, sun_reflect_MagicAccessorImpl, Opt) \ template(reflect_method_accessor_klass, sun_reflect_MethodAccessorImpl, Opt_Only_JDK14NewRef) \ template(reflect_constructor_accessor_klass, sun_reflect_ConstructorAccessorImpl, Opt_Only_JDK14NewRef) \ template(reflect_delegating_classloader_klass, sun_reflect_DelegatingClassLoader, Opt) \ template(reflect_constant_pool_klass, sun_reflect_ConstantPool, Opt_Only_JDK15) \ template(reflect_unsafe_static_field_accessor_impl_klass, sun_reflect_UnsafeStaticFieldAccessorImpl, Opt_Only_JDK15) \ \ /* support for dynamic typing; it's OK if these are NULL in earlier JDKs */ \ template(MethodHandle_klass, java_dyn_MethodHandle, Opt) \ template(MemberName_klass, sun_dyn_MemberName, Opt) \ template(MethodHandleImpl_klass, sun_dyn_MethodHandleImpl, Opt) \ template(AdapterMethodHandle_klass, sun_dyn_AdapterMethodHandle, Opt) \ template(BoundMethodHandle_klass, sun_dyn_BoundMethodHandle, Opt) \ template(DirectMethodHandle_klass, sun_dyn_DirectMethodHandle, Opt) \ template(MethodType_klass, java_dyn_MethodType, Opt) \ template(MethodTypeForm_klass, java_dyn_MethodTypeForm, Opt) \ template(WrongMethodTypeException_klass, java_dyn_WrongMethodTypeException, Opt) \ template(Linkage_klass, java_dyn_Linkage, Opt) \ template(CallSite_klass, java_dyn_CallSite, Opt) \ template(CallSiteImpl_klass, sun_dyn_CallSiteImpl, Opt) \ template(Dynamic_klass, java_dyn_Dynamic, Opt) \ /* Note: MethodHandle must be first, and Dynamic last in group */ \ \ template(vector_klass, java_util_Vector, Pre) \ template(hashtable_klass, java_util_Hashtable, Pre) \ template(stringBuffer_klass, java_lang_StringBuffer, Pre) \ \ /* It's NULL in non-1.4 JDKs. */ \ template(stackTraceElement_klass, java_lang_StackTraceElement, Opt) \ /* Universe::is_gte_jdk14x_version() is not set up by this point. */ \ /* It's okay if this turns out to be NULL in non-1.4 JDKs. */ \ template(java_nio_Buffer_klass, java_nio_Buffer, Opt) \ \ /* If this class isn't present, it won't be referenced. */ \ template(sun_misc_AtomicLongCSImpl_klass, sun_misc_AtomicLongCSImpl, Opt) \ \ template(sun_jkernel_DownloadManager_klass, sun_jkernel_DownloadManager, Opt_Kernel) \ \ /* Preload boxing klasses */ \ template(boolean_klass, java_lang_Boolean, Pre) \ template(char_klass, java_lang_Character, Pre) \ template(float_klass, java_lang_Float, Pre) \ template(double_klass, java_lang_Double, Pre) \ template(byte_klass, java_lang_Byte, Pre) \ template(short_klass, java_lang_Short, Pre) \ template(int_klass, java_lang_Integer, Pre) \ template(long_klass, java_lang_Long, Pre) \ /*end*/ class SystemDictionary : AllStatic { friend class VMStructs; friend class CompactingPermGenGen; friend class SystemDictionaryHandles; NOT_PRODUCT(friend class instanceKlassKlass;) public: enum WKID { NO_WKID = 0, #define WK_KLASS_ENUM(name, ignore_s, ignore_o) WK_KLASS_ENUM_NAME(name), WK_KLASSES_DO(WK_KLASS_ENUM) #undef WK_KLASS_ENUM WKID_LIMIT, FIRST_WKID = NO_WKID + 1 }; enum InitOption { Pre, // preloaded; error if not present // Order is significant. Options before this point require resolve_or_fail. // Options after this point will use resolve_or_null instead. Opt, // preload tried; NULL if not present Opt_Only_JDK14NewRef, // preload tried; use only with NewReflection Opt_Only_JDK15, // preload tried; use only with JDK1.5+ Opt_Kernel, // preload tried only #ifdef KERNEL OPTION_LIMIT, CEIL_LG_OPTION_LIMIT = 4 // OPTION_LIMIT <= (1<* cp_patches, TRAPS); // Resolve from stream (called by jni_DefineClass and JVM_DefineClass) static klassOop resolve_from_stream(symbolHandle class_name, Handle class_loader, Handle protection_domain, ClassFileStream* st, TRAPS); // Lookup an already loaded class. If not found NULL is returned. static klassOop find(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS); // Lookup an already loaded instance or array class. // Do not make any queries to class loaders; consult only the cache. // If not found NULL is returned. static klassOop find_instance_or_array_klass(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS); // If the given name is known to vmSymbols, return the well-know klass: static klassOop find_well_known_klass(symbolOop class_name); // Lookup an instance or array class that has already been loaded // either into the given class loader, or else into another class // loader that is constrained (via loader constraints) to produce // a consistent class. Do not take protection domains into account. // Do not make any queries to class loaders; consult only the cache. // Return NULL if the class is not found. // // This function is a strict superset of find_instance_or_array_klass. // This function (the unchecked version) makes a conservative prediction // of the result of the checked version, assuming successful lookup. // If both functions return non-null, they must return the same value. // Also, the unchecked version may sometimes be non-null where the // checked version is null. This can occur in several ways: // 1. No query has yet been made to the class loader. // 2. The class loader was queried, but chose not to delegate. // 3. ClassLoader.checkPackageAccess rejected a proposed protection domain. // 4. Loading was attempted, but there was a linkage error of some sort. // In all of these cases, the loader constraints on this type are // satisfied, and it is safe for classes in the given class loader // to manipulate strongly-typed values of the found class, subject // to local linkage and access checks. static klassOop find_constrained_instance_or_array_klass(symbolHandle class_name, Handle class_loader, TRAPS); // Iterate over all klasses in dictionary // Just the classes from defining class loaders static void classes_do(void f(klassOop)); // Added for initialize_itable_for_klass to handle exceptions static void classes_do(void f(klassOop, TRAPS), TRAPS); // All classes, and their class loaders static void classes_do(void f(klassOop, oop)); // All classes, and their class loaders // (added for helpers that use HandleMarks and ResourceMarks) static void classes_do(void f(klassOop, oop, TRAPS), TRAPS); // All entries in the placeholder table and their class loaders static void placeholders_do(void f(symbolOop, oop)); // Iterate over all methods in all klasses in dictionary static void methods_do(void f(methodOop)); // Garbage collection support // This method applies "blk->do_oop" to all the pointers to "system" // classes and loaders. static void always_strong_oops_do(OopClosure* blk); static void always_strong_classes_do(OopClosure* blk); // This method applies "blk->do_oop" to all the placeholders. static void placeholders_do(OopClosure* blk); // Unload (that is, break root links to) all unmarked classes and // loaders. Returns "true" iff something was unloaded. static bool do_unloading(BoolObjectClosure* is_alive); // Applies "f->do_oop" to all root oops in the system dictionary. static void oops_do(OopClosure* f); // System loader lock static oop system_loader_lock() { return _system_loader_lock_obj; } private: // Traverses preloaded oops: various system classes. These are // guaranteed to be in the perm gen. static void preloaded_oops_do(OopClosure* f); static void lazily_loaded_oops_do(OopClosure* f); public: // Sharing support. static void reorder_dictionary(); static void copy_buckets(char** top, char* end); static void copy_table(char** top, char* end); static void reverse(); static void set_shared_dictionary(HashtableBucket* t, int length, int number_of_entries); // Printing static void print() PRODUCT_RETURN; static void print_class_statistics() PRODUCT_RETURN; static void print_method_statistics() PRODUCT_RETURN; // Number of contained klasses // This is both fully loaded classes and classes in the process // of being loaded static int number_of_classes(); // Monotonically increasing counter which grows as classes are // loaded or modifications such as hot-swapping or setting/removing // of breakpoints are performed static inline int number_of_modifications() { assert_locked_or_safepoint(Compile_lock); return _number_of_modifications; } // Needed by evolution and breakpoint code static inline void notice_modification() { assert_locked_or_safepoint(Compile_lock); ++_number_of_modifications; } // Verification static void verify(); #ifdef ASSERT static bool is_internal_format(symbolHandle class_name); #endif // Verify class is in dictionary static void verify_obj_klass_present(Handle obj, symbolHandle class_name, Handle class_loader); // Initialization static void initialize(TRAPS); // Fast access to commonly used classes (preloaded) static klassOop check_klass(klassOop k) { assert(k != NULL, "preloaded klass not initialized"); return k; } static klassOop check_klass_Pre(klassOop k) { return check_klass(k); } static klassOop check_klass_Opt(klassOop k) { return k; } static klassOop check_klass_Opt_Kernel(klassOop k) { return k; } //== Opt static klassOop check_klass_Opt_Only_JDK15(klassOop k) { assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only"); return k; } static klassOop check_klass_Opt_Only_JDK14NewRef(klassOop k) { assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only"); // despite the optional loading, if you use this it must be present: return check_klass(k); } static bool initialize_wk_klass(WKID id, int init_opt, TRAPS); static void initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS); static void initialize_wk_klasses_through(WKID end_id, WKID &start_id, TRAPS) { int limit = (int)end_id + 1; initialize_wk_klasses_until((WKID) limit, start_id, THREAD); } public: #define WK_KLASS_DECLARE(name, ignore_symbol, option) \ static klassOop name() { return check_klass_##option(_well_known_klasses[WK_KLASS_ENUM_NAME(name)]); } WK_KLASSES_DO(WK_KLASS_DECLARE); #undef WK_KLASS_DECLARE // Local definition for direct access to the private array: #define WK_KLASS(name) _well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)] static klassOop box_klass(BasicType t) { assert((uint)t < T_VOID+1, "range check"); return check_klass(_box_klasses[t]); } static BasicType box_klass_type(klassOop k); // inverse of box_klass // methods returning lazily loaded klasses // The corresponding method to load the class must be called before calling them. static klassOop abstract_ownable_synchronizer_klass() { return check_klass(_abstract_ownable_synchronizer_klass); } static void load_abstract_ownable_synchronizer_klass(TRAPS); private: // Tells whether ClassLoader.loadClassInternal is present static bool has_loadClassInternal() { return _has_loadClassInternal; } public: // Tells whether ClassLoader.checkPackageAccess is present static bool has_checkPackageAccess() { return _has_checkPackageAccess; } static bool class_klass_loaded() { return WK_KLASS(class_klass) != NULL; } static bool cloneable_klass_loaded() { return WK_KLASS(cloneable_klass) != NULL; } // Returns default system loader static oop java_system_loader(); // Compute the default system loader static void compute_java_system_loader(TRAPS); private: // Mirrors for primitive classes (created eagerly) static oop check_mirror(oop m) { assert(m != NULL, "mirror not initialized"); return m; } public: // Note: java_lang_Class::primitive_type is the inverse of java_mirror // Check class loader constraints static bool add_loader_constraint(symbolHandle name, Handle loader1, Handle loader2, TRAPS); static char* check_signature_loaders(symbolHandle signature, Handle loader1, Handle loader2, bool is_method, TRAPS); // JSR 292 // find the java.dyn.MethodHandles::invoke method for a given signature static methodOop find_method_handle_invoke(symbolHandle signature, Handle class_loader, Handle protection_domain, TRAPS); // ask Java to compute the java.dyn.MethodType object for a given signature static Handle compute_method_handle_type(symbolHandle signature, Handle class_loader, Handle protection_domain, TRAPS); // ask Java to create a dynamic call site, while linking an invokedynamic op static Handle make_dynamic_call_site(KlassHandle caller, int caller_method_idnum, int caller_bci, symbolHandle name, methodHandle mh_invoke, TRAPS); // coordinate with Java about bootstrap methods static Handle find_bootstrap_method(KlassHandle caller, // This argument is non-null only when a // classfile attribute has been found: KlassHandle search_bootstrap_klass, TRAPS); // Utility for printing loader "name" as part of tracing constraints static const char* loader_name(oop loader) { return ((loader) == NULL ? "" : instanceKlass::cast((loader)->klass())->name()->as_C_string() ); } // Record the error when the first attempt to resolve a reference from a constant // pool entry to a class fails. static void add_resolution_error(constantPoolHandle pool, int which, symbolHandle error); static symbolOop find_resolution_error(constantPoolHandle pool, int which); private: enum Constants { _loader_constraint_size = 107, // number of entries in constraint table _resolution_error_size = 107, // number of entries in resolution error table _invoke_method_size = 139, // number of entries in invoke method table _nof_buckets = 1009 // number of buckets in hash table }; // Static variables // Hashtable holding loaded classes. static Dictionary* _dictionary; // Hashtable holding placeholders for classes being loaded. static PlaceholderTable* _placeholders; // Hashtable holding classes from the shared archive. static Dictionary* _shared_dictionary; // Monotonically increasing counter which grows with // _number_of_classes as well as hot-swapping and breakpoint setting // and removal. static int _number_of_modifications; // Lock object for system class loader static oop _system_loader_lock_obj; // Constraints on class loaders static LoaderConstraintTable* _loader_constraints; // Resolution errors static ResolutionErrorTable* _resolution_errors; // Invoke methods (JSR 292) static SymbolPropertyTable* _invoke_method_table; public: // for VM_CounterDecay iteration support friend class CounterDecay; static klassOop try_get_next_class(); private: static void validate_protection_domain(instanceKlassHandle klass, Handle class_loader, Handle protection_domain, TRAPS); friend class VM_PopulateDumpSharedSpace; friend class TraversePlaceholdersClosure; static Dictionary* dictionary() { return _dictionary; } static Dictionary* shared_dictionary() { return _shared_dictionary; } static PlaceholderTable* placeholders() { return _placeholders; } static LoaderConstraintTable* constraints() { return _loader_constraints; } static ResolutionErrorTable* resolution_errors() { return _resolution_errors; } static SymbolPropertyTable* invoke_method_table() { return _invoke_method_table; } // Basic loading operations static klassOop resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS); static klassOop resolve_array_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS); static instanceKlassHandle handle_parallel_super_load(symbolHandle class_name, symbolHandle supername, Handle class_loader, Handle protection_domain, Handle lockObject, TRAPS); // Wait on SystemDictionary_lock; unlocks lockObject before // waiting; relocks lockObject with correct recursion count // after waiting, but before reentering SystemDictionary_lock // to preserve lock order semantics. static void double_lock_wait(Handle lockObject, TRAPS); static void define_instance_class(instanceKlassHandle k, TRAPS); static instanceKlassHandle find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS); static instanceKlassHandle load_shared_class(symbolHandle class_name, Handle class_loader, TRAPS); static instanceKlassHandle load_shared_class(instanceKlassHandle ik, Handle class_loader, TRAPS); static instanceKlassHandle load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS); static Handle compute_loader_lock_object(Handle class_loader, TRAPS); static void check_loader_lock_contention(Handle loader_lock, TRAPS); static bool is_parallelCapable(Handle class_loader); static klassOop find_shared_class(symbolHandle class_name); // Setup link to hierarchy static void add_to_hierarchy(instanceKlassHandle k, TRAPS); private: // We pass in the hashtable index so we can calculate it outside of // the SystemDictionary_lock. // Basic find on loaded classes static klassOop find_class(int index, unsigned int hash, symbolHandle name, Handle loader); // Basic find on classes in the midst of being loaded static symbolOop find_placeholder(int index, unsigned int hash, symbolHandle name, Handle loader); // Basic find operation of loaded classes and classes in the midst // of loading; used for assertions and verification only. static oop find_class_or_placeholder(symbolHandle class_name, Handle class_loader); // Updating entry in dictionary // Add a completely loaded class static void add_klass(int index, symbolHandle class_name, Handle class_loader, KlassHandle obj); // Add a placeholder for a class being loaded static void add_placeholder(int index, symbolHandle class_name, Handle class_loader); static void remove_placeholder(int index, symbolHandle class_name, Handle class_loader); // Performs cleanups after resolve_super_or_fail. This typically needs // to be called on failure. // Won't throw, but can block. static void resolution_cleanups(symbolHandle class_name, Handle class_loader, TRAPS); // Initialization static void initialize_preloaded_classes(TRAPS); // Class loader constraints static void check_constraints(int index, unsigned int hash, instanceKlassHandle k, Handle loader, bool defining, TRAPS); static void update_dictionary(int d_index, unsigned int d_hash, int p_index, unsigned int p_hash, instanceKlassHandle k, Handle loader, TRAPS); // Variables holding commonly used klasses (preloaded) static klassOop _well_known_klasses[]; // Lazily loaded klasses static volatile klassOop _abstract_ownable_synchronizer_klass; // table of box klasses (int_klass, etc.) static klassOop _box_klasses[T_VOID+1]; static oop _java_system_loader; static bool _has_loadClassInternal; static bool _has_checkPackageAccess; }; // Cf. vmSymbols vs. vmSymbolHandles class SystemDictionaryHandles : AllStatic { public: #define WK_KLASS_HANDLE_DECLARE(name, ignore_symbol, option) \ static KlassHandle name() { \ SystemDictionary::name(); \ klassOop* loc = &SystemDictionary::_well_known_klasses[SystemDictionary::WK_KLASS_ENUM_NAME(name)]; \ return KlassHandle(loc, true); \ } WK_KLASSES_DO(WK_KLASS_HANDLE_DECLARE); #undef WK_KLASS_HANDLE_DECLARE static KlassHandle box_klass(BasicType t); };