diff -r 000000000000 -r a61af66fc99e src/share/vm/classfile/systemDictionary.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/classfile/systemDictionary.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,581 @@ +/* + * Copyright 1997-2007 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 SystemDictionary : AllStatic { + friend class VMStructs; + friend class CompactingPermGenGen; + NOT_PRODUCT(friend class instanceKlassKlass;) + + public: + // Returns a class with a given class name and class loader. Loads the + // class if needed. If not found a NoClassDefFoundError or a + // ClassNotFoundException is thrown, depending on the value on the + // throw_error flag. For most uses the throw_error argument should be set + // to true. + + static klassOop resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS); + // Convenient call for null loader and protection domain. + static klassOop resolve_or_fail(symbolHandle class_name, bool throw_error, TRAPS); +private: + // handle error translation for resolve_or_null results + static klassOop handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS); + +public: + + // Returns a class with a given class name and class loader. + // Loads the class if needed. If not found NULL is returned. + static klassOop resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS); + // Version with null loader and protection domain + static klassOop resolve_or_null(symbolHandle class_name, TRAPS); + + // Resolve a superclass or superinterface. Called from ClassFileParser, + // parse_interfaces, resolve_instance_class_or_null, load_shared_class + // "child_name" is the class whose super class or interface is being resolved. + static klassOop resolve_super_or_fail(symbolHandle child_name, + symbolHandle class_name, + Handle class_loader, + Handle protection_domain, + bool is_superclass, + TRAPS); + + // Parse new stream. This won't update the system dictionary or + // class hierarchy, simply parse the stream. Used by JVMTI RedefineClasses. + static klassOop parse_stream(symbolHandle class_name, + Handle class_loader, + Handle protection_domain, + ClassFileStream* st, + 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); + + // 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; + } + +public: + static klassOop object_klass() { return check_klass(_object_klass); } + static klassOop string_klass() { return check_klass(_string_klass); } + static klassOop class_klass() { return check_klass(_class_klass); } + static klassOop cloneable_klass() { return check_klass(_cloneable_klass); } + static klassOop classloader_klass() { return check_klass(_classloader_klass); } + static klassOop serializable_klass() { return check_klass(_serializable_klass); } + static klassOop system_klass() { return check_klass(_system_klass); } + + static klassOop throwable_klass() { return check_klass(_throwable_klass); } + static klassOop error_klass() { return check_klass(_error_klass); } + static klassOop threaddeath_klass() { return check_klass(_threaddeath_klass); } + static klassOop exception_klass() { return check_klass(_exception_klass); } + static klassOop runtime_exception_klass() { return check_klass(_runtime_exception_klass); } + static klassOop classNotFoundException_klass() { return check_klass(_classNotFoundException_klass); } + static klassOop noClassDefFoundError_klass() { return check_klass(_noClassDefFoundError_klass); } + static klassOop linkageError_klass() { return check_klass(_linkageError_klass); } + static klassOop ClassCastException_klass() { return check_klass(_classCastException_klass); } + static klassOop ArrayStoreException_klass() { return check_klass(_arrayStoreException_klass); } + static klassOop virtualMachineError_klass() { return check_klass(_virtualMachineError_klass); } + static klassOop OutOfMemoryError_klass() { return check_klass(_outOfMemoryError_klass); } + static klassOop StackOverflowError_klass() { return check_klass(_StackOverflowError_klass); } + static klassOop IllegalMonitorStateException_klass() { return check_klass(_illegalMonitorStateException_klass); } + static klassOop protectionDomain_klass() { return check_klass(_protectionDomain_klass); } + static klassOop AccessControlContext_klass() { return check_klass(_AccessControlContext_klass); } + static klassOop reference_klass() { return check_klass(_reference_klass); } + static klassOop soft_reference_klass() { return check_klass(_soft_reference_klass); } + static klassOop weak_reference_klass() { return check_klass(_weak_reference_klass); } + static klassOop final_reference_klass() { return check_klass(_final_reference_klass); } + static klassOop phantom_reference_klass() { return check_klass(_phantom_reference_klass); } + static klassOop finalizer_klass() { return check_klass(_finalizer_klass); } + + static klassOop thread_klass() { return check_klass(_thread_klass); } + static klassOop threadGroup_klass() { return check_klass(_threadGroup_klass); } + static klassOop properties_klass() { return check_klass(_properties_klass); } + static klassOop reflect_accessible_object_klass() { return check_klass(_reflect_accessible_object_klass); } + static klassOop reflect_field_klass() { return check_klass(_reflect_field_klass); } + static klassOop reflect_method_klass() { return check_klass(_reflect_method_klass); } + static klassOop reflect_constructor_klass() { return check_klass(_reflect_constructor_klass); } + static klassOop reflect_method_accessor_klass() { + assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only"); + return check_klass(_reflect_method_accessor_klass); + } + static klassOop reflect_constructor_accessor_klass() { + assert(JDK_Version::is_gte_jdk14x_version() && UseNewReflection, "JDK 1.4 only"); + return check_klass(_reflect_constructor_accessor_klass); + } + // NOTE: needed too early in bootstrapping process to have checks based on JDK version + static klassOop reflect_magic_klass() { return _reflect_magic_klass; } + static klassOop reflect_delegating_classloader_klass() { return _reflect_delegating_classloader_klass; } + static klassOop reflect_constant_pool_klass() { + assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only"); + return _reflect_constant_pool_klass; + } + static klassOop reflect_unsafe_static_field_accessor_impl_klass() { + assert(JDK_Version::is_gte_jdk15x_version(), "JDK 1.5 only"); + return _reflect_unsafe_static_field_accessor_impl_klass; + } + + static klassOop vector_klass() { return check_klass(_vector_klass); } + static klassOop hashtable_klass() { return check_klass(_hashtable_klass); } + static klassOop stringBuffer_klass() { return check_klass(_stringBuffer_klass); } + static klassOop stackTraceElement_klass() { return check_klass(_stackTraceElement_klass); } + + static klassOop java_nio_Buffer_klass() { return check_klass(_java_nio_Buffer_klass); } + + static klassOop sun_misc_AtomicLongCSImpl_klass() { return _sun_misc_AtomicLongCSImpl_klass; } + + // To support incremental JRE downloads (KERNEL JRE). Null if not present. + static klassOop sun_jkernel_DownloadManager_klass() { return _sun_jkernel_DownloadManager_klass; } + + static klassOop boolean_klass() { return check_klass(_boolean_klass); } + static klassOop char_klass() { return check_klass(_char_klass); } + static klassOop float_klass() { return check_klass(_float_klass); } + static klassOop double_klass() { return check_klass(_double_klass); } + static klassOop byte_klass() { return check_klass(_byte_klass); } + static klassOop short_klass() { return check_klass(_short_klass); } + static klassOop int_klass() { return check_klass(_int_klass); } + static klassOop long_klass() { return check_klass(_long_klass); } + + 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 _class_klass != NULL; } + static bool cloneable_klass_loaded() { return _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); + + // 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 + _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; + +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; } + + // 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 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 _object_klass; + static klassOop _string_klass; + static klassOop _class_klass; + static klassOop _cloneable_klass; + static klassOop _classloader_klass; + static klassOop _serializable_klass; + static klassOop _system_klass; + + static klassOop _throwable_klass; + static klassOop _error_klass; + static klassOop _threaddeath_klass; + static klassOop _exception_klass; + static klassOop _runtime_exception_klass; + static klassOop _classNotFoundException_klass; + static klassOop _noClassDefFoundError_klass; + static klassOop _linkageError_klass; + static klassOop _classCastException_klass; + static klassOop _arrayStoreException_klass; + static klassOop _virtualMachineError_klass; + static klassOop _outOfMemoryError_klass; + static klassOop _StackOverflowError_klass; + static klassOop _illegalMonitorStateException_klass; + static klassOop _protectionDomain_klass; + static klassOop _AccessControlContext_klass; + static klassOop _reference_klass; + static klassOop _soft_reference_klass; + static klassOop _weak_reference_klass; + static klassOop _final_reference_klass; + static klassOop _phantom_reference_klass; + static klassOop _finalizer_klass; + + static klassOop _thread_klass; + static klassOop _threadGroup_klass; + static klassOop _properties_klass; + static klassOop _reflect_accessible_object_klass; + static klassOop _reflect_field_klass; + static klassOop _reflect_method_klass; + static klassOop _reflect_constructor_klass; + // 1.4 reflection implementation + static klassOop _reflect_magic_klass; + static klassOop _reflect_method_accessor_klass; + static klassOop _reflect_constructor_accessor_klass; + static klassOop _reflect_delegating_classloader_klass; + // 1.5 annotations implementation + static klassOop _reflect_constant_pool_klass; + static klassOop _reflect_unsafe_static_field_accessor_impl_klass; + + static klassOop _stringBuffer_klass; + static klassOop _vector_klass; + static klassOop _hashtable_klass; + + static klassOop _stackTraceElement_klass; + + static klassOop _java_nio_Buffer_klass; + + static klassOop _sun_misc_AtomicLongCSImpl_klass; + + // KERNEL JRE support. + static klassOop _sun_jkernel_DownloadManager_klass; + + // Lazily loaded klasses + static volatile klassOop _abstract_ownable_synchronizer_klass; + + // Box klasses + static klassOop _boolean_klass; + static klassOop _char_klass; + static klassOop _float_klass; + static klassOop _double_klass; + static klassOop _byte_klass; + static klassOop _short_klass; + static klassOop _int_klass; + static klassOop _long_klass; + + // table of same + static klassOop _box_klasses[T_VOID+1]; + + static oop _java_system_loader; + + static bool _has_loadClassInternal; + static bool _has_checkPackageAccess; +};