aoqi@0: /*
aoqi@0:  * Copyright (c) 2012, 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP
aoqi@0: #define SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP
aoqi@0: 
aoqi@0: #include "memory/allocation.hpp"
aoqi@0: #include "memory/memRegion.hpp"
aoqi@0: #include "memory/metaspace.hpp"
aoqi@0: #include "memory/metaspaceCounters.hpp"
aoqi@0: #include "runtime/mutex.hpp"
aoqi@0: #include "utilities/growableArray.hpp"
mgronlun@7367: #include "utilities/macros.hpp"
aoqi@0: #if INCLUDE_TRACE
mgronlun@7367: #include "utilities/ticks.hpp"
aoqi@0: #endif
aoqi@0: 
aoqi@0: //
aoqi@0: // A class loader represents a linkset. Conceptually, a linkset identifies
aoqi@0: // the complete transitive closure of resolved links that a dynamic linker can
aoqi@0: // produce.
aoqi@0: //
aoqi@0: // A ClassLoaderData also encapsulates the allocation space, called a metaspace,
aoqi@0: // used by the dynamic linker to allocate the runtime representation of all
aoqi@0: // the types it defines.
aoqi@0: //
aoqi@0: // ClassLoaderData are stored in the runtime representation of classes and the
aoqi@0: // system dictionary, are roots of garbage collection, and provides iterators
aoqi@0: // for root tracing and other GC operations.
aoqi@0: 
aoqi@0: class ClassLoaderData;
aoqi@0: class JNIMethodBlock;
aoqi@0: class JNIHandleBlock;
aoqi@0: class Metadebug;
aoqi@0: 
aoqi@0: // GC root for walking class loader data created
aoqi@0: 
aoqi@0: class ClassLoaderDataGraph : public AllStatic {
aoqi@0:   friend class ClassLoaderData;
aoqi@0:   friend class ClassLoaderDataGraphMetaspaceIterator;
stefank@6992:   friend class ClassLoaderDataGraphKlassIteratorAtomic;
aoqi@0:   friend class VMStructs;
aoqi@0:  private:
aoqi@0:   // All CLDs (except the null CLD) can be reached by walking _head->_next->...
aoqi@0:   static ClassLoaderData* _head;
aoqi@0:   static ClassLoaderData* _unloading;
aoqi@0:   // CMS support.
aoqi@0:   static ClassLoaderData* _saved_head;
aoqi@0:   static ClassLoaderData* _saved_unloading;
aoqi@0:   static bool _should_purge;
aoqi@0: 
aoqi@0:   static ClassLoaderData* add(Handle class_loader, bool anonymous, TRAPS);
aoqi@0:   static void post_class_unload_events(void);
stefank@7333:   static void clean_metaspaces();
aoqi@0:  public:
aoqi@0:   static ClassLoaderData* find_or_create(Handle class_loader, TRAPS);
aoqi@0:   static void purge();
aoqi@0:   static void clear_claimed_marks();
stefank@6992:   // oops do
aoqi@0:   static void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim);
stefank@6992:   static void keep_alive_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim);
aoqi@0:   static void always_strong_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim);
stefank@6992:   // cld do
stefank@6992:   static void cld_do(CLDClosure* cl);
stefank@6992:   static void roots_cld_do(CLDClosure* strong, CLDClosure* weak);
stefank@6992:   static void keep_alive_cld_do(CLDClosure* cl);
stefank@6992:   static void always_strong_cld_do(CLDClosure* cl);
stefank@6992:   // klass do
aoqi@0:   static void classes_do(KlassClosure* klass_closure);
aoqi@0:   static void classes_do(void f(Klass* const));
aoqi@0:   static void loaded_classes_do(KlassClosure* klass_closure);
aoqi@0:   static void classes_unloading_do(void f(Klass* const));
stefank@7333:   static bool do_unloading(BoolObjectClosure* is_alive, bool clean_alive);
aoqi@0: 
aoqi@0:   // CMS support.
aoqi@0:   static void remember_new_clds(bool remember) { _saved_head = (remember ? _head : NULL); }
aoqi@0:   static GrowableArray<ClassLoaderData*>* new_clds();
aoqi@0: 
aoqi@0:   static void set_should_purge(bool b) { _should_purge = b; }
aoqi@0:   static void purge_if_needed() {
aoqi@0:     // Only purge the CLDG for CMS if concurrent sweep is complete.
aoqi@0:     if (_should_purge) {
aoqi@0:       purge();
aoqi@0:       // reset for next time.
aoqi@0:       set_should_purge(false);
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
stefank@7333:   static void free_deallocate_lists();
stefank@7333: 
aoqi@0:   static void dump_on(outputStream * const out) PRODUCT_RETURN;
aoqi@0:   static void dump() { dump_on(tty); }
aoqi@0:   static void verify();
aoqi@0: 
stefank@6992:   static bool unload_list_contains(const void* x);
aoqi@0: #ifndef PRODUCT
aoqi@0:   static bool contains_loader_data(ClassLoaderData* loader_data);
aoqi@0: #endif
aoqi@0: 
aoqi@0: #if INCLUDE_TRACE
aoqi@0:  private:
aoqi@0:   static Ticks _class_unload_time;
aoqi@0:   static void class_unload_event(Klass* const k);
aoqi@0: #endif
aoqi@0: };
aoqi@0: 
aoqi@0: // ClassLoaderData class
aoqi@0: 
aoqi@0: class ClassLoaderData : public CHeapObj<mtClass> {
aoqi@0:   friend class VMStructs;
aoqi@0:  private:
aoqi@0:   class Dependencies VALUE_OBJ_CLASS_SPEC {
aoqi@0:     objArrayOop _list_head;
aoqi@0:     void locked_add(objArrayHandle last,
aoqi@0:                     objArrayHandle new_dependency,
aoqi@0:                     Thread* THREAD);
aoqi@0:    public:
aoqi@0:     Dependencies() : _list_head(NULL) {}
aoqi@0:     Dependencies(TRAPS) : _list_head(NULL) {
aoqi@0:       init(CHECK);
aoqi@0:     }
aoqi@0:     void add(Handle dependency, TRAPS);
aoqi@0:     void init(TRAPS);
aoqi@0:     void oops_do(OopClosure* f);
aoqi@0:   };
aoqi@0: 
aoqi@0:   friend class ClassLoaderDataGraph;
stefank@6992:   friend class ClassLoaderDataGraphKlassIteratorAtomic;
aoqi@0:   friend class ClassLoaderDataGraphMetaspaceIterator;
aoqi@0:   friend class MetaDataFactory;
aoqi@0:   friend class Method;
aoqi@0: 
aoqi@0:   static ClassLoaderData * _the_null_class_loader_data;
aoqi@0: 
aoqi@0:   oop _class_loader;          // oop used to uniquely identify a class loader
aoqi@0:                               // class loader or a canonical class path
aoqi@0:   Dependencies _dependencies; // holds dependencies from this class loader
aoqi@0:                               // data to others.
aoqi@0: 
aoqi@0:   Metaspace * _metaspace;  // Meta-space where meta-data defined by the
aoqi@0:                            // classes in the class loader are allocated.
aoqi@0:   Mutex* _metaspace_lock;  // Locks the metaspace for allocations and setup.
aoqi@0:   bool _unloading;         // true if this class loader goes away
stefank@6974:   bool _keep_alive;        // if this CLD is kept alive without a keep_alive_object().
aoqi@0:   bool _is_anonymous;      // if this CLD is for an anonymous class
aoqi@0:   volatile int _claimed;   // true if claimed, for example during GC traces.
aoqi@0:                            // To avoid applying oop closure more than once.
aoqi@0:                            // Has to be an int because we cas it.
aoqi@0:   Klass* _klasses;         // The classes defined by the class loader.
aoqi@0: 
aoqi@0:   JNIHandleBlock* _handles; // Handles to constant pool arrays
aoqi@0: 
aoqi@0:   // These method IDs are created for the class loader and set to NULL when the
aoqi@0:   // class loader is unloaded.  They are rarely freed, only for redefine classes
aoqi@0:   // and if they lose a data race in InstanceKlass.
aoqi@0:   JNIMethodBlock*                  _jmethod_ids;
aoqi@0: 
aoqi@0:   // Metadata to be deallocated when it's safe at class unloading, when
aoqi@0:   // this class loader isn't unloaded itself.
aoqi@0:   GrowableArray<Metadata*>*      _deallocate_list;
aoqi@0: 
aoqi@0:   // Support for walking class loader data objects
aoqi@0:   ClassLoaderData* _next; /// Next loader_datas created
aoqi@0: 
aoqi@0:   // ReadOnly and ReadWrite metaspaces (static because only on the null
aoqi@0:   // class loader for now).
aoqi@0:   static Metaspace* _ro_metaspace;
aoqi@0:   static Metaspace* _rw_metaspace;
aoqi@0: 
aoqi@0:   void set_next(ClassLoaderData* next) { _next = next; }
aoqi@0:   ClassLoaderData* next() const        { return _next; }
aoqi@0: 
aoqi@0:   ClassLoaderData(Handle h_class_loader, bool is_anonymous, Dependencies dependencies);
aoqi@0:   ~ClassLoaderData();
aoqi@0: 
aoqi@0:   void set_metaspace(Metaspace* m) { _metaspace = m; }
aoqi@0: 
aoqi@0:   JNIHandleBlock* handles() const;
aoqi@0:   void set_handles(JNIHandleBlock* handles);
aoqi@0: 
aoqi@0:   Mutex* metaspace_lock() const { return _metaspace_lock; }
aoqi@0: 
aoqi@0:   // GC interface.
aoqi@0:   void clear_claimed()          { _claimed = 0; }
aoqi@0:   bool claimed() const          { return _claimed == 1; }
aoqi@0:   bool claim();
aoqi@0: 
aoqi@0:   void unload();
aoqi@0:   bool keep_alive() const       { return _keep_alive; }
aoqi@0:   void classes_do(void f(Klass*));
aoqi@0:   void loaded_classes_do(KlassClosure* klass_closure);
aoqi@0:   void classes_do(void f(InstanceKlass*));
aoqi@0: 
aoqi@0:   // Deallocate free list during class unloading.
aoqi@0:   void free_deallocate_list();
aoqi@0: 
aoqi@0:   // Allocate out of this class loader data
aoqi@0:   MetaWord* allocate(size_t size);
aoqi@0: 
aoqi@0:  public:
stefank@6992: 
stefank@6992:   bool is_alive(BoolObjectClosure* is_alive_closure) const;
stefank@6992: 
aoqi@0:   // Accessors
aoqi@0:   Metaspace* metaspace_or_null() const     { return _metaspace; }
aoqi@0: 
aoqi@0:   static ClassLoaderData* the_null_class_loader_data() {
aoqi@0:     return _the_null_class_loader_data;
aoqi@0:   }
aoqi@0: 
aoqi@0:   bool is_anonymous() const { return _is_anonymous; }
aoqi@0: 
aoqi@0:   static void init_null_class_loader_data() {
aoqi@0:     assert(_the_null_class_loader_data == NULL, "cannot initialize twice");
aoqi@0:     assert(ClassLoaderDataGraph::_head == NULL, "cannot initialize twice");
aoqi@0: 
aoqi@0:     // We explicitly initialize the Dependencies object at a later phase in the initialization
aoqi@0:     _the_null_class_loader_data = new ClassLoaderData((oop)NULL, false, Dependencies());
aoqi@0:     ClassLoaderDataGraph::_head = _the_null_class_loader_data;
aoqi@0:     assert(_the_null_class_loader_data->is_the_null_class_loader_data(), "Must be");
aoqi@0:     if (DumpSharedSpaces) {
aoqi@0:       _the_null_class_loader_data->initialize_shared_metaspaces();
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   bool is_the_null_class_loader_data() const {
aoqi@0:     return this == _the_null_class_loader_data;
aoqi@0:   }
aoqi@0:   bool is_ext_class_loader_data() const;
aoqi@0: 
aoqi@0:   // The Metaspace is created lazily so may be NULL.  This
aoqi@0:   // method will allocate a Metaspace if needed.
aoqi@0:   Metaspace* metaspace_non_null();
aoqi@0: 
aoqi@0:   oop class_loader() const      { return _class_loader; }
aoqi@0: 
stefank@6974:   // The object the GC is using to keep this ClassLoaderData alive.
stefank@6974:   oop keep_alive_object() const;
stefank@6974: 
aoqi@0:   // Returns true if this class loader data is for a loader going away.
aoqi@0:   bool is_unloading() const     {
aoqi@0:     assert(!(is_the_null_class_loader_data() && _unloading), "The null class loader can never be unloaded");
aoqi@0:     return _unloading;
aoqi@0:   }
stefank@6974: 
stefank@6974:   // Used to make sure that this CLD is not unloaded.
aoqi@0:   void set_keep_alive(bool value) { _keep_alive = value; }
aoqi@0: 
aoqi@0:   unsigned int identity_hash() {
aoqi@0:     return _class_loader == NULL ? 0 : _class_loader->identity_hash();
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Used when tracing from klasses.
aoqi@0:   void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim);
aoqi@0: 
aoqi@0:   void classes_do(KlassClosure* klass_closure);
aoqi@0: 
aoqi@0:   JNIMethodBlock* jmethod_ids() const              { return _jmethod_ids; }
aoqi@0:   void set_jmethod_ids(JNIMethodBlock* new_block)  { _jmethod_ids = new_block; }
aoqi@0: 
aoqi@0:   void print_value() { print_value_on(tty); }
aoqi@0:   void print_value_on(outputStream* out) const;
aoqi@0:   void dump(outputStream * const out) PRODUCT_RETURN;
aoqi@0:   void verify();
aoqi@0:   const char* loader_name();
aoqi@0: 
aoqi@0:   jobject add_handle(Handle h);
aoqi@0:   void add_class(Klass* k);
aoqi@0:   void remove_class(Klass* k);
aoqi@0:   bool contains_klass(Klass* k);
aoqi@0:   void record_dependency(Klass* to, TRAPS);
aoqi@0:   void init_dependencies(TRAPS);
aoqi@0: 
aoqi@0:   void add_to_deallocate_list(Metadata* m);
aoqi@0: 
aoqi@0:   static ClassLoaderData* class_loader_data(oop loader);
aoqi@0:   static ClassLoaderData* class_loader_data_or_null(oop loader);
aoqi@0:   static ClassLoaderData* anonymous_class_loader_data(oop loader, TRAPS);
aoqi@0:   static void print_loader(ClassLoaderData *loader_data, outputStream *out);
aoqi@0: 
aoqi@0:   // CDS support
aoqi@0:   Metaspace* ro_metaspace();
aoqi@0:   Metaspace* rw_metaspace();
aoqi@0:   void initialize_shared_metaspaces();
aoqi@0: };
aoqi@0: 
stefank@6992: // An iterator that distributes Klasses to parallel worker threads.
stefank@6992: class ClassLoaderDataGraphKlassIteratorAtomic : public StackObj {
asiebenborn@7765:  Klass* volatile _next_klass;
stefank@6992:  public:
stefank@6992:   ClassLoaderDataGraphKlassIteratorAtomic();
stefank@6992:   Klass* next_klass();
stefank@6992:  private:
stefank@6992:   static Klass* next_klass_in_cldg(Klass* klass);
stefank@6992: };
stefank@6992: 
aoqi@0: class ClassLoaderDataGraphMetaspaceIterator : public StackObj {
aoqi@0:   ClassLoaderData* _data;
aoqi@0:  public:
aoqi@0:   ClassLoaderDataGraphMetaspaceIterator();
aoqi@0:   ~ClassLoaderDataGraphMetaspaceIterator();
aoqi@0:   bool repeat() { return _data != NULL; }
aoqi@0:   Metaspace* get_next() {
aoqi@0:     assert(_data != NULL, "Should not be NULL in call to the iterator");
aoqi@0:     Metaspace* result = _data->metaspace_or_null();
aoqi@0:     _data = _data->next();
aoqi@0:     // This result might be NULL for class loaders without metaspace
aoqi@0:     // yet.  It would be nice to return only non-null results but
aoqi@0:     // there is no guarantee that there will be a non-null result
aoqi@0:     // down the list so the caller is going to have to check.
aoqi@0:     return result;
aoqi@0:   }
aoqi@0: };
aoqi@0: #endif // SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP