coleenp@4037: /*
coleenp@4037:  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
coleenp@4037:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
coleenp@4037:  *
coleenp@4037:  * This code is free software; you can redistribute it and/or modify it
coleenp@4037:  * under the terms of the GNU General Public License version 2 only, as
coleenp@4037:  * published by the Free Software Foundation.
coleenp@4037:  *
coleenp@4037:  * This code is distributed in the hope that it will be useful, but WITHOUT
coleenp@4037:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
coleenp@4037:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
coleenp@4037:  * version 2 for more details (a copy is included in the LICENSE file that
coleenp@4037:  * accompanied this code).
coleenp@4037:  *
coleenp@4037:  * You should have received a copy of the GNU General Public License version
coleenp@4037:  * 2 along with this work; if not, write to the Free Software Foundation,
coleenp@4037:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
coleenp@4037:  *
coleenp@4037:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
coleenp@4037:  * or visit www.oracle.com if you need additional information or have any
coleenp@4037:  * questions.
coleenp@4037:  *
coleenp@4037:  */
coleenp@4037: 
coleenp@4037: // A ClassLoaderData identifies the full set of class types that a class
coleenp@4037: // loader's name resolution strategy produces for a given configuration of the
coleenp@4037: // class loader.
coleenp@4037: // Class types in the ClassLoaderData may be defined by from class file binaries
coleenp@4037: // provided by the class loader, or from other class loader it interacts with
coleenp@4037: // according to its name resolution strategy.
coleenp@4037: //
coleenp@4037: // Class loaders that implement a deterministic name resolution strategy
coleenp@4037: // (including with respect to their delegation behavior), such as the boot, the
coleenp@4037: // extension, and the system loaders of the JDK's built-in class loader
coleenp@4037: // hierarchy, always produce the same linkset for a given configuration.
coleenp@4037: //
coleenp@4037: // ClassLoaderData carries information related to a linkset (e.g.,
coleenp@4037: // metaspace holding its klass definitions).
coleenp@4037: // The System Dictionary and related data structures (e.g., placeholder table,
coleenp@4037: // loader constraints table) as well as the runtime representation of classes
coleenp@4037: // only reference ClassLoaderData.
coleenp@4037: //
coleenp@4037: // Instances of java.lang.ClassLoader holds a pointer to a ClassLoaderData that
coleenp@4037: // that represent the loader's "linking domain" in the JVM.
coleenp@4037: //
coleenp@4037: // The bootstrap loader (represented by NULL) also has a ClassLoaderData,
coleenp@4037: // the singleton class the_null_class_loader_data().
coleenp@4037: 
coleenp@4037: #include "precompiled.hpp"
coleenp@4037: #include "classfile/classLoaderData.hpp"
coleenp@4037: #include "classfile/classLoaderData.inline.hpp"
coleenp@4037: #include "classfile/javaClasses.hpp"
coleenp@4037: #include "classfile/systemDictionary.hpp"
coleenp@4037: #include "code/codeCache.hpp"
coleenp@4037: #include "memory/metadataFactory.hpp"
coleenp@4037: #include "memory/metaspaceShared.hpp"
coleenp@4037: #include "prims/jvmtiRedefineClasses.hpp"
coleenp@4037: #include "runtime/jniHandles.hpp"
coleenp@4037: #include "runtime/mutex.hpp"
coleenp@4037: #include "runtime/safepoint.hpp"
coleenp@4037: #include "runtime/synchronizer.hpp"
coleenp@4037: #include "utilities/growableArray.hpp"
coleenp@4037: #include "utilities/ostream.hpp"
coleenp@4037: 
coleenp@4037: ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
coleenp@4037: 
coleenp@4037: ClassLoaderData::ClassLoaderData(Handle h_class_loader) : _class_loader(h_class_loader()),
coleenp@4037:   _metaspace(NULL), _unloading(false), _klasses(NULL),
coleenp@4037:   _claimed(0), _jmethod_ids(NULL), _handles(NULL),
coleenp@4037:   _deallocate_list(NULL), _next(NULL),
coleenp@4037:   _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
coleenp@4037:     // empty
coleenp@4037: }
coleenp@4037: 
coleenp@4037: bool ClassLoaderData::claim() {
coleenp@4037:   if (_claimed == 1) {
coleenp@4037:     return false;
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
coleenp@4037:   if (must_claim && !claim()) {
coleenp@4037:     return;
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   f->do_oop(&_class_loader);
coleenp@4037:   _handles->oops_do(f);
coleenp@4037:   if (klass_closure != NULL) {
coleenp@4037:     classes_do(klass_closure);
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
coleenp@4037:   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
coleenp@4037:     klass_closure->do_klass(k);
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
coleenp@4037:   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
coleenp@4037:     if (k->oop_is_instance()) {
coleenp@4037:       f(InstanceKlass::cast(k));
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderData::record_dependency(Klass* k, TRAPS) {
coleenp@4037:   ClassLoaderData * const from_cld = this;
coleenp@4037:   ClassLoaderData * const to_cld = k->class_loader_data();
coleenp@4037: 
coleenp@4037:   // Records dependency between non-null class loaders only.
coleenp@4037:   if (to_cld->is_the_null_class_loader_data() || from_cld->is_the_null_class_loader_data()) {
coleenp@4037:     return;
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   // Check that this dependency isn't from the same or parent class_loader
coleenp@4037:   oop to = to_cld->class_loader();
coleenp@4037:   oop from = from_cld->class_loader();
coleenp@4037: 
coleenp@4037:   oop curr = from;
coleenp@4037:   while (curr != NULL) {
coleenp@4037:     if (curr == to) {
coleenp@4037:       return; // this class loader is in the parent list, no need to add it.
coleenp@4037:     }
coleenp@4037:     curr = java_lang_ClassLoader::parent(curr);
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   // It's a dependency we won't find through GC, add it. This is relatively rare
coleenp@4037:   from_cld->add_dependency(to_cld, CHECK);
coleenp@4037: }
coleenp@4037: 
coleenp@4037: bool ClassLoaderData::has_dependency(ClassLoaderData* dependency) {
coleenp@4037:   oop loader = dependency->class_loader();
coleenp@4037: 
coleenp@4037:   // Get objArrayOop out of the class_loader oop and see if this dependency
coleenp@4037:   // is there.  Don't safepoint!  These are all oops.
coleenp@4037:   // Dependency list is (oop class_loader, objArrayOop next)
coleenp@4037:   objArrayOop ok = (objArrayOop)java_lang_ClassLoader::dependencies(class_loader());
coleenp@4037:   while (ok != NULL) {
coleenp@4037:     if (ok->obj_at(0) == loader) {
coleenp@4037:       return true;
coleenp@4037:     }
coleenp@4037:     ok = (objArrayOop)ok->obj_at(1);
coleenp@4037:   }
coleenp@4037:   return false;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderData::add_dependency(ClassLoaderData* dependency, TRAPS) {
coleenp@4037:   // Minimize the number of duplicates in the list.
coleenp@4037:   if (has_dependency(dependency)) {
coleenp@4037:     return;
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   // Create a new dependency node with fields for (class_loader, next)
coleenp@4037:   objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
coleenp@4037:   deps->obj_at_put(0, dependency->class_loader());
coleenp@4037: 
coleenp@4037:   // Add this lock free, using compare and exchange, need barriers for GC
coleenp@4037:   // Do the barrier first.
coleenp@4037:   HeapWord* addr = java_lang_ClassLoader::dependencies_addr(class_loader());
coleenp@4037:   while (true) {
coleenp@4037:     oop old_dependency = java_lang_ClassLoader::dependencies(class_loader());
coleenp@4037:     deps->obj_at_put(1, old_dependency);
coleenp@4037: 
coleenp@4037:     oop newold = oopDesc::atomic_compare_exchange_oop((oop)deps, addr, old_dependency, true);
coleenp@4037:     if (newold == old_dependency) {
coleenp@4037:       update_barrier_set((void*)addr, (oop)deps);
coleenp@4037:       // we won the race to add this dependency
coleenp@4037:       break;
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: 
coleenp@4037: void ClassLoaderDataGraph::clear_claimed_marks() {
coleenp@4037:   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
coleenp@4037:     cld->clear_claimed();
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderData::add_class(Klass* k) {
coleenp@4037:   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
coleenp@4037:   Klass* old_value = _klasses;
coleenp@4037:   k->set_next_link(old_value);
coleenp@4037:   // link the new item into the list
coleenp@4037:   _klasses = k;
coleenp@4037: 
coleenp@4037:   if (TraceClassLoaderData && k->class_loader_data() != NULL) {
coleenp@4037:     ResourceMark rm;
coleenp@4037:     tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
coleenp@4037:                   PTR_FORMAT " loader: " PTR_FORMAT " %s",
coleenp@4037:                   k,
coleenp@4037:                   k->external_name(),
coleenp@4037:                   k->class_loader_data(),
coleenp@4037:                   k->class_loader(),
coleenp@4037:                   k->class_loader() != NULL ? k->class_loader()->klass()->external_name() : "NULL"
coleenp@4037:       );
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: // This is called by InstanceKlass::deallocate_contents() to remove the
coleenp@4037: // scratch_class for redefine classes.  We need a lock because there it may not
coleenp@4037: // be called at a safepoint if there's an error.
coleenp@4037: void ClassLoaderData::remove_class(Klass* scratch_class) {
coleenp@4037:   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
coleenp@4037:   Klass* prev = NULL;
coleenp@4037:   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
coleenp@4037:     if (k == scratch_class) {
coleenp@4037:       if (prev == NULL) {
coleenp@4037:         _klasses = k->next_link();
coleenp@4037:       } else {
coleenp@4037:         Klass* next = k->next_link();
coleenp@4037:         prev->set_next_link(next);
coleenp@4037:       }
coleenp@4037:       return;
coleenp@4037:     }
coleenp@4037:     prev = k;
coleenp@4037:   }
coleenp@4037:   ShouldNotReachHere();   // should have found this class!!
coleenp@4037: }
coleenp@4037: 
coleenp@4037: ClassLoaderData::~ClassLoaderData() {
coleenp@4037:   Metaspace *m = _metaspace;
coleenp@4037:   if (m != NULL) {
coleenp@4037:     _metaspace = NULL;
coleenp@4037:     // release the metaspace
coleenp@4037:     delete m;
coleenp@4037:     // release the handles
coleenp@4037:     if (_handles != NULL) {
coleenp@4037:       JNIHandleBlock::release_block(_handles);
coleenp@4037:       _handles = NULL;
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   // Clear all the JNI handles for methods
coleenp@4037:   // These aren't deallocated and are going to look like a leak, but that's
coleenp@4037:   // needed because we can't really get rid of jmethodIDs because we don't
coleenp@4037:   // know when native code is going to stop using them.  The spec says that
coleenp@4037:   // they're "invalid" but existing programs likely rely on their being
coleenp@4037:   // NULL after class unloading.
coleenp@4037:   if (_jmethod_ids != NULL) {
coleenp@4037:     Method::clear_jmethod_ids(this);
coleenp@4037:   }
coleenp@4037:   // Delete lock
coleenp@4037:   delete _metaspace_lock;
coleenp@4037: 
coleenp@4037:   // Delete free list
coleenp@4037:   if (_deallocate_list != NULL) {
coleenp@4037:     delete _deallocate_list;
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: Metaspace* ClassLoaderData::metaspace_non_null() {
coleenp@4037:   // If the metaspace has not been allocated, create a new one.  Might want
coleenp@4037:   // to create smaller arena for Reflection class loaders also.
coleenp@4037:   // The reason for the delayed allocation is because some class loaders are
coleenp@4037:   // simply for delegating with no metadata of their own.
coleenp@4037:   if (_metaspace == NULL) {
coleenp@4037:     MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
coleenp@4037:     // Check again if metaspace has been allocated while we were getting this lock.
coleenp@4037:     if (_metaspace != NULL) {
coleenp@4037:       return _metaspace;
coleenp@4037:     }
coleenp@4037:     if (class_loader() == NULL) {
coleenp@4037:       assert(this == the_null_class_loader_data(), "Must be");
coleenp@4037:       size_t word_size = Metaspace::first_chunk_word_size();
coleenp@4037:       set_metaspace(new Metaspace(_metaspace_lock, word_size));
coleenp@4037:     } else {
coleenp@4037:       set_metaspace(new Metaspace(_metaspace_lock));  // default size for now.
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037:   return _metaspace;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: JNIHandleBlock* ClassLoaderData::handles() const           { return _handles; }
coleenp@4037: void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; }
coleenp@4037: 
coleenp@4037: jobject ClassLoaderData::add_handle(Handle h) {
coleenp@4037:   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
coleenp@4037:   if (handles() == NULL) {
coleenp@4037:     set_handles(JNIHandleBlock::allocate_block());
coleenp@4037:   }
coleenp@4037:   return handles()->allocate_handle(h());
coleenp@4037: }
coleenp@4037: 
coleenp@4037: // Add this metadata pointer to be freed when it's safe.  This is only during
coleenp@4037: // class unloading because Handles might point to this metadata field.
coleenp@4037: void ClassLoaderData::add_to_deallocate_list(Metadata* m) {
coleenp@4037:   // Metadata in shared region isn't deleted.
coleenp@4037:   if (!m->is_shared()) {
coleenp@4037:     MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
coleenp@4037:     if (_deallocate_list == NULL) {
coleenp@4037:       _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true);
coleenp@4037:     }
coleenp@4037:     _deallocate_list->append_if_missing(m);
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: // Deallocate free metadata on the free list.  How useful the PermGen was!
coleenp@4037: void ClassLoaderData::free_deallocate_list() {
coleenp@4037:   // Don't need lock, at safepoint
coleenp@4037:   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
coleenp@4037:   if (_deallocate_list == NULL) {
coleenp@4037:     return;
coleenp@4037:   }
coleenp@4037:   // Go backwards because this removes entries that are freed.
coleenp@4037:   for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
coleenp@4037:     Metadata* m = _deallocate_list->at(i);
coleenp@4037:     if (!m->on_stack()) {
coleenp@4037:       _deallocate_list->remove_at(i);
coleenp@4037:       // There are only three types of metadata that we deallocate directly.
coleenp@4037:       // Cast them so they can be used by the template function.
coleenp@4037:       if (m->is_method()) {
coleenp@4037:         MetadataFactory::free_metadata(this, (Method*)m);
coleenp@4037:       } else if (m->is_constantPool()) {
coleenp@4037:         MetadataFactory::free_metadata(this, (ConstantPool*)m);
coleenp@4037:       } else if (m->is_klass()) {
coleenp@4037:         MetadataFactory::free_metadata(this, (InstanceKlass*)m);
coleenp@4037:       } else {
coleenp@4037:         ShouldNotReachHere();
coleenp@4037:       }
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: #ifndef PRODUCT
coleenp@4037: void ClassLoaderData::print_loader(ClassLoaderData *loader_data, outputStream* out) {
coleenp@4037:   oop class_loader = loader_data->class_loader();
coleenp@4037:   out->print("%s", SystemDictionary::loader_name(class_loader));
coleenp@4037: }
coleenp@4037: 
coleenp@4037: // Define to dump klasses
coleenp@4037: #undef CLD_DUMP_KLASSES
coleenp@4037: 
coleenp@4037: void ClassLoaderData::dump(outputStream * const out) {
coleenp@4037:   ResourceMark rm;
coleenp@4037:   out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {",
coleenp@4037:       this, class_loader(),
coleenp@4037:       class_loader() != NULL ? class_loader()->klass() : NULL,
coleenp@4037:       class_loader() != NULL ? class_loader()->klass()->external_name() : "NULL");
coleenp@4037:   if (claimed()) out->print(" claimed ");
coleenp@4037:   if (is_unloading()) out->print(" unloading ");
coleenp@4037:   out->print(" handles " INTPTR_FORMAT, handles());
coleenp@4037:   out->cr();
coleenp@4037:   if (metaspace_or_null() != NULL) {
coleenp@4037:     out->print_cr("metaspace: " PTR_FORMAT, metaspace_or_null());
coleenp@4037:     metaspace_or_null()->dump(out);
coleenp@4037:   } else {
coleenp@4037:     out->print_cr("metaspace: NULL");
coleenp@4037:   }
coleenp@4037: 
coleenp@4037: #ifdef CLD_DUMP_KLASSES
coleenp@4037:   if (Verbose) {
coleenp@4037:     ResourceMark rm;
coleenp@4037:     Klass* k = _klasses;
coleenp@4037:     while (k != NULL) {
coleenp@4037:       out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(),
coleenp@4037:           k->has_modified_oops(), k->has_accumulated_modified_oops());
coleenp@4037:       k = k->next_link();
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: #endif  // CLD_DUMP_KLASSES
coleenp@4037: #undef CLD_DUMP_KLASSES
coleenp@4037:   if (_jmethod_ids != NULL) {
coleenp@4037:     Method::print_jmethod_ids(this, out);
coleenp@4037:   }
coleenp@4037:   out->print_cr("}");
coleenp@4037: }
coleenp@4037: #endif // PRODUCT
coleenp@4037: 
coleenp@4037: void ClassLoaderData::verify() {
coleenp@4037:   oop cl = class_loader();
coleenp@4037: 
coleenp@4037:   guarantee(this == class_loader_data(cl), "Must be the same");
coleenp@4037:   guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data(), "must be");
coleenp@4037: 
coleenp@4037:   // Verify the integrity of the allocated space.
coleenp@4037:   if (metaspace_or_null() != NULL) {
coleenp@4037:     metaspace_or_null()->verify();
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
coleenp@4037:     guarantee(k->class_loader_data() == this, "Must be the same");
coleenp@4037:     k->verify();
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: // GC root of class loader data created.
coleenp@4037: ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
coleenp@4037: ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
coleenp@4037: ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
coleenp@4037: 
coleenp@4037: 
coleenp@4037: // Add a new class loader data node to the list.  Assign the newly created
coleenp@4037: // ClassLoaderData into the java/lang/ClassLoader object as a hidden field
coleenp@4037: ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader_data) {
coleenp@4037:   // Not assigned a class loader data yet.
coleenp@4037:   // Create one.
coleenp@4037:   ClassLoaderData* *list_head = &_head;
coleenp@4037:   ClassLoaderData* next = _head;
coleenp@4037:   ClassLoaderData* cld = new ClassLoaderData(loader_data);
coleenp@4037: 
coleenp@4037:   // First, Atomically set it.
coleenp@4037:   ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
coleenp@4037:   if (old != NULL) {
coleenp@4037:     delete cld;
coleenp@4037:     // Returns the data.
coleenp@4037:     return old;
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   // We won the race, and therefore the task of adding the data to the list of
coleenp@4037:   // class loader data
coleenp@4037:   do {
coleenp@4037:     cld->set_next(next);
coleenp@4037:     ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
coleenp@4037:     if (exchanged == next) {
coleenp@4037:       if (TraceClassLoaderData) {
coleenp@4037:         tty->print("[ClassLoaderData: ");
coleenp@4037:         tty->print("create class loader data "PTR_FORMAT, cld);
coleenp@4037:         tty->print(" for instance "PTR_FORMAT" of ", cld->class_loader());
coleenp@4037:         loader_data->klass()->name()->print_symbol_on(tty);
coleenp@4037:         tty->print_cr("]");
coleenp@4037:       }
coleenp@4037:       return cld;
coleenp@4037:     }
coleenp@4037:     next = exchanged;
coleenp@4037:   } while (true);
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
coleenp@4037:   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
coleenp@4037:     cld->oops_do(f, klass_closure, must_claim);
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
coleenp@4037:   if (ClassUnloading) {
coleenp@4037:     ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim);
coleenp@4037:   } else {
coleenp@4037:     ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim);
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
coleenp@4037:   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
coleenp@4037:     cld->classes_do(klass_closure);
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
coleenp@4037:   assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?");
coleenp@4037: 
coleenp@4037:   GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>();
coleenp@4037: 
coleenp@4037:   // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true);
coleenp@4037:   ClassLoaderData* curr = _head;
coleenp@4037:   while (curr != _saved_head) {
coleenp@4037:     if (!curr->claimed()) {
coleenp@4037:       array->push(curr);
coleenp@4037: 
coleenp@4037:       if (TraceClassLoaderData) {
coleenp@4037:         tty->print("[ClassLoaderData] found new CLD: ");
coleenp@4037:         curr->print_value_on(tty);
coleenp@4037:         tty->cr();
coleenp@4037:       }
coleenp@4037:     }
coleenp@4037: 
coleenp@4037:     curr = curr->_next;
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   return array;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: #ifndef PRODUCT
coleenp@4037: // for debugging and hsfind(x)
coleenp@4037: bool ClassLoaderDataGraph::contains(address x) {
coleenp@4037:   // I think we need the _metaspace_lock taken here because the class loader
coleenp@4037:   // data graph could be changing while we are walking it (new entries added,
coleenp@4037:   // new entries being unloaded, etc).
coleenp@4037:   if (DumpSharedSpaces) {
coleenp@4037:     // There are only two metaspaces to worry about.
coleenp@4037:     ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
coleenp@4037:     return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x));
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) {
coleenp@4037:     return true;
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
coleenp@4037:     if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
coleenp@4037:       return true;
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   // Could also be on an unloading list which is okay, ie. still allocated
coleenp@4037:   // for a little while.
coleenp@4037:   for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) {
coleenp@4037:     if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) {
coleenp@4037:       return true;
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037:   return false;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
coleenp@4037:   for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
coleenp@4037:     if (loader_data == data) {
coleenp@4037:       return true;
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   return false;
coleenp@4037: }
coleenp@4037: #endif // PRODUCT
coleenp@4037: 
coleenp@4037: // Move class loader data from main list to the unloaded list for unloading
coleenp@4037: // and deallocation later.
coleenp@4037: bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive) {
coleenp@4037:   ClassLoaderData* data = _head;
coleenp@4037:   ClassLoaderData* prev = NULL;
coleenp@4037:   bool seen_dead_loader = false;
coleenp@4037:   // mark metadata seen on the stack and code cache so we can delete
coleenp@4037:   // unneeded entries.
coleenp@4037:   bool has_redefined_a_class = JvmtiExport::has_redefined_a_class();
coleenp@4037:   MetadataOnStackMark md_on_stack;
coleenp@4037:   while (data != NULL) {
coleenp@4037:     if (data->class_loader() == NULL || is_alive->do_object_b(data->class_loader())) {
coleenp@4037:       assert(data->claimed(), "class loader data must have been claimed");
coleenp@4037:       if (has_redefined_a_class) {
coleenp@4037:         data->classes_do(InstanceKlass::purge_previous_versions);
coleenp@4037:       }
coleenp@4037:       data->free_deallocate_list();
coleenp@4037:       prev = data;
coleenp@4037:       data = data->next();
coleenp@4037:       continue;
coleenp@4037:     }
coleenp@4037:     seen_dead_loader = true;
coleenp@4037:     ClassLoaderData* dead = data;
coleenp@4037:     dead->mark_for_unload();
coleenp@4037:     if (TraceClassLoaderData) {
coleenp@4037:       tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, dead);
coleenp@4037:       tty->print(" for instance "PTR_FORMAT" of ", dead->class_loader());
coleenp@4037:       dead->class_loader()->klass()->name()->print_symbol_on(tty);
coleenp@4037:       tty->print_cr("]");
coleenp@4037:     }
coleenp@4037:     data = data->next();
coleenp@4037:     // Remove from loader list.
coleenp@4037:     if (prev != NULL) {
coleenp@4037:       prev->set_next(data);
coleenp@4037:     } else {
coleenp@4037:       assert(dead == _head, "sanity check");
coleenp@4037:       _head = data;
coleenp@4037:     }
coleenp@4037:     dead->set_next(_unloading);
coleenp@4037:     _unloading = dead;
coleenp@4037:   }
coleenp@4037:   return seen_dead_loader;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderDataGraph::purge() {
coleenp@4037:   ClassLoaderData* list = _unloading;
coleenp@4037:   _unloading = NULL;
coleenp@4037:   ClassLoaderData* next = list;
coleenp@4037:   while (next != NULL) {
coleenp@4037:     ClassLoaderData* purge_me = next;
coleenp@4037:     next = purge_me->next();
coleenp@4037:     delete purge_me;
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: // CDS support
coleenp@4037: 
coleenp@4037: // Global metaspaces for writing information to the shared archive.  When
coleenp@4037: // application CDS is supported, we may need one per metaspace, so this
coleenp@4037: // sort of looks like it.
coleenp@4037: Metaspace* ClassLoaderData::_ro_metaspace = NULL;
coleenp@4037: Metaspace* ClassLoaderData::_rw_metaspace = NULL;
coleenp@4037: static bool _shared_metaspaces_initialized = false;
coleenp@4037: 
coleenp@4037: // Initialize shared metaspaces (change to call from somewhere not lazily)
coleenp@4037: void ClassLoaderData::initialize_shared_metaspaces() {
coleenp@4037:   assert(DumpSharedSpaces, "only use this for dumping shared spaces");
coleenp@4037:   assert(this == ClassLoaderData::the_null_class_loader_data(),
coleenp@4037:          "only supported for null loader data for now");
coleenp@4037:   assert (!_shared_metaspaces_initialized, "only initialize once");
coleenp@4037:   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
coleenp@4037:   _ro_metaspace = new Metaspace(_metaspace_lock, SharedReadOnlySize/wordSize);
coleenp@4037:   _rw_metaspace = new Metaspace(_metaspace_lock, SharedReadWriteSize/wordSize);
coleenp@4037:   _shared_metaspaces_initialized = true;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: Metaspace* ClassLoaderData::ro_metaspace() {
coleenp@4037:   assert(_ro_metaspace != NULL, "should already be initialized");
coleenp@4037:   return _ro_metaspace;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: Metaspace* ClassLoaderData::rw_metaspace() {
coleenp@4037:   assert(_rw_metaspace != NULL, "should already be initialized");
coleenp@4037:   return _rw_metaspace;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: 
coleenp@4037: ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() {
coleenp@4037:   _data = ClassLoaderDataGraph::_head;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {}
coleenp@4037: 
coleenp@4037: #ifndef PRODUCT
coleenp@4037: // callable from debugger
coleenp@4037: extern "C" int print_loader_data_graph() {
coleenp@4037:   ClassLoaderDataGraph::dump_on(tty);
coleenp@4037:   return 0;
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderDataGraph::verify() {
coleenp@4037:   for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
coleenp@4037:     data->verify();
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderDataGraph::dump_on(outputStream * const out) {
coleenp@4037:   for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
coleenp@4037:     data->dump(out);
coleenp@4037:   }
coleenp@4037:   MetaspaceAux::dump(out);
coleenp@4037: }
coleenp@4037: 
coleenp@4037: void ClassLoaderData::print_value_on(outputStream* out) const {
coleenp@4037:   if (class_loader() == NULL) {
coleenp@4037:     out->print_cr("NULL class_loader");
coleenp@4037:   } else {
coleenp@4037:     out->print("class loader "PTR_FORMAT, this);
coleenp@4037:     class_loader()->print_value_on(out);
coleenp@4037:   }
coleenp@4037: }
coleenp@4037: #endif // PRODUCT