--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/classfile/dictionary.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,609 @@
+/*
+ * Copyright 2003-2007 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.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_dictionary.cpp.incl"
+
+
+DictionaryEntry*  Dictionary::_current_class_entry = NULL;
+int               Dictionary::_current_class_index =    0;
+
+
+Dictionary::Dictionary(int table_size)
+  : TwoOopHashtable(table_size, sizeof(DictionaryEntry)) {
+  _current_class_index = 0;
+  _current_class_entry = NULL;
+};
+
+
+
+Dictionary::Dictionary(int table_size, HashtableBucket* t,
+                       int number_of_entries)
+  : TwoOopHashtable(table_size, sizeof(DictionaryEntry), t, number_of_entries) {
+  _current_class_index = 0;
+  _current_class_entry = NULL;
+};
+
+
+DictionaryEntry* Dictionary::new_entry(unsigned int hash, klassOop klass,
+                                       oop loader) {
+  DictionaryEntry* entry;
+  entry = (DictionaryEntry*)Hashtable::new_entry(hash, klass);
+  entry->set_loader(loader);
+  entry->set_pd_set(NULL);
+  return entry;
+}
+
+
+DictionaryEntry* Dictionary::new_entry() {
+  DictionaryEntry* entry = (DictionaryEntry*)Hashtable::new_entry(0L, NULL);
+  entry->set_loader(NULL);
+  entry->set_pd_set(NULL);
+  return entry;
+}
+
+
+void Dictionary::free_entry(DictionaryEntry* entry) {
+  // avoid recursion when deleting linked list
+  while (entry->pd_set() != NULL) {
+    ProtectionDomainEntry* to_delete = entry->pd_set();
+    entry->set_pd_set(to_delete->next());
+    delete to_delete;
+  }
+  Hashtable::free_entry(entry);
+}
+
+
+bool DictionaryEntry::contains_protection_domain(oop protection_domain) const {
+#ifdef ASSERT
+  if (protection_domain == instanceKlass::cast(klass())->protection_domain()) {
+    // Ensure this doesn't show up in the pd_set (invariant)
+    bool in_pd_set = false;
+    for (ProtectionDomainEntry* current = _pd_set;
+                                current != NULL;
+                                current = current->next()) {
+      if (current->protection_domain() == protection_domain) {
+        in_pd_set = true;
+        break;
+      }
+    }
+    if (in_pd_set) {
+      assert(false, "A klass's protection domain should not show up "
+                    "in its sys. dict. PD set");
+    }
+  }
+#endif /* ASSERT */
+
+  if (protection_domain == instanceKlass::cast(klass())->protection_domain()) {
+    // Succeeds trivially
+    return true;
+  }
+
+  for (ProtectionDomainEntry* current = _pd_set;
+                              current != NULL;
+                              current = current->next()) {
+    if (current->protection_domain() == protection_domain) return true;
+  }
+  return false;
+}
+
+
+void DictionaryEntry::add_protection_domain(oop protection_domain) {
+  assert_locked_or_safepoint(SystemDictionary_lock);
+  if (!contains_protection_domain(protection_domain)) {
+    ProtectionDomainEntry* new_head =
+                new ProtectionDomainEntry(protection_domain, _pd_set);
+    // Warning: Preserve store ordering.  The SystemDictionary is read
+    //          without locks.  The new ProtectionDomainEntry must be
+    //          complete before other threads can be allowed to see it
+    //          via a store to _pd_set.
+    OrderAccess::release_store_ptr(&_pd_set, new_head);
+  }
+  if (TraceProtectionDomainVerification && WizardMode) {
+    print();
+  }
+}
+
+
+bool Dictionary::do_unloading(BoolObjectClosure* is_alive) {
+  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint")
+  bool class_was_unloaded = false;
+  int  index = 0; // Defined here for portability! Do not move
+
+  // Remove unloadable entries and classes from system dictionary
+  // The placeholder array has been handled in always_strong_oops_do.
+  DictionaryEntry* probe = NULL;
+  for (index = 0; index < table_size(); index++) {
+    for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
+      probe = *p;
+      klassOop e = probe->klass();
+      oop class_loader = probe->loader();
+
+      instanceKlass* ik = instanceKlass::cast(e);
+      if (ik->previous_versions() != NULL) {
+        // This klass has previous versions so see what we can cleanup
+        // while it is safe to do so.
+
+        int gc_count = 0;    // leave debugging breadcrumbs
+        int live_count = 0;
+
+        // RC_TRACE macro has an embedded ResourceMark
+        RC_TRACE(0x00000200, ("unload: %s: previous version length=%d",
+          ik->external_name(), ik->previous_versions()->length()));
+
+        for (int i = ik->previous_versions()->length() - 1; i >= 0; i--) {
+          // check the previous versions array for GC'ed weak refs
+          PreviousVersionNode * pv_node = ik->previous_versions()->at(i);
+          jweak cp_ref = pv_node->prev_constant_pool();
+          assert(cp_ref != NULL, "weak cp ref was unexpectedly cleared");
+          if (cp_ref == NULL) {
+            delete pv_node;
+            ik->previous_versions()->remove_at(i);
+            // Since we are traversing the array backwards, we don't have to
+            // do anything special with the index.
+            continue;  // robustness
+          }
+
+          constantPoolOop pvcp = (constantPoolOop)JNIHandles::resolve(cp_ref);
+          if (pvcp == NULL) {
+            // this entry has been GC'ed so remove it
+            delete pv_node;
+            ik->previous_versions()->remove_at(i);
+            // Since we are traversing the array backwards, we don't have to
+            // do anything special with the index.
+            gc_count++;
+            continue;
+          } else {
+            RC_TRACE(0x00000200, ("unload: previous version @%d is alive", i));
+            if (is_alive->do_object_b(pvcp)) {
+              live_count++;
+            } else {
+              guarantee(false, "sanity check");
+            }
+          }
+
+          GrowableArray<jweak>* method_refs = pv_node->prev_EMCP_methods();
+          if (method_refs != NULL) {
+            RC_TRACE(0x00000200, ("unload: previous methods length=%d",
+              method_refs->length()));
+            for (int j = method_refs->length() - 1; j >= 0; j--) {
+              jweak method_ref = method_refs->at(j);
+              assert(method_ref != NULL, "weak method ref was unexpectedly cleared");
+              if (method_ref == NULL) {
+                method_refs->remove_at(j);
+                // Since we are traversing the array backwards, we don't have to
+                // do anything special with the index.
+                continue;  // robustness
+              }
+
+              methodOop method = (methodOop)JNIHandles::resolve(method_ref);
+              if (method == NULL) {
+                // this method entry has been GC'ed so remove it
+                JNIHandles::destroy_weak_global(method_ref);
+                method_refs->remove_at(j);
+              } else {
+                // RC_TRACE macro has an embedded ResourceMark
+                RC_TRACE(0x00000200,
+                  ("unload: %s(%s): prev method @%d in version @%d is alive",
+                  method->name()->as_C_string(),
+                  method->signature()->as_C_string(), j, i));
+              }
+            }
+          }
+        }
+        assert(ik->previous_versions()->length() == live_count, "sanity check");
+        RC_TRACE(0x00000200,
+          ("unload: previous version stats: live=%d, GC'ed=%d", live_count,
+          gc_count));
+      }
+
+      // Non-unloadable classes were handled in always_strong_oops_do
+      if (!is_strongly_reachable(class_loader, e)) {
+        // Entry was not visited in phase1 (negated test from phase1)
+        assert(class_loader != NULL, "unloading entry with null class loader");
+        oop k_def_class_loader = ik->class_loader();
+
+        // Do we need to delete this system dictionary entry?
+        bool purge_entry = false;
+
+        // Do we need to delete this system dictionary entry?
+        if (!is_alive->do_object_b(class_loader)) {
+          // If the loader is not live this entry should always be
+          // removed (will never be looked up again). Note that this is
+          // not the same as unloading the referred class.
+          if (k_def_class_loader == class_loader) {
+            // This is the defining entry, so the referred class is about
+            // to be unloaded.
+            // Notify the debugger and clean up the class.
+            guarantee(!is_alive->do_object_b(e),
+                      "klass should not be live if defining loader is not");
+            class_was_unloaded = true;
+            // notify the debugger
+            if (JvmtiExport::should_post_class_unload()) {
+              JvmtiExport::post_class_unload(ik->as_klassOop());
+            }
+
+            // notify ClassLoadingService of class unload
+            ClassLoadingService::notify_class_unloaded(ik);
+
+            // Clean up C heap
+            ik->release_C_heap_structures();
+          }
+          // Also remove this system dictionary entry.
+          purge_entry = true;
+
+        } else {
+          // The loader in this entry is alive. If the klass is dead,
+          // the loader must be an initiating loader (rather than the
+          // defining loader). Remove this entry.
+          if (!is_alive->do_object_b(e)) {
+            guarantee(!is_alive->do_object_b(k_def_class_loader),
+                      "defining loader should not be live if klass is not");
+            // If we get here, the class_loader must not be the defining
+            // loader, it must be an initiating one.
+            assert(k_def_class_loader != class_loader,
+                   "cannot have live defining loader and unreachable klass");
+
+            // Loader is live, but class and its defining loader are dead.
+            // Remove the entry. The class is going away.
+            purge_entry = true;
+          }
+        }
+
+        if (purge_entry) {
+          *p = probe->next();
+          if (probe == _current_class_entry) {
+            _current_class_entry = NULL;
+          }
+          free_entry(probe);
+          continue;
+        }
+      }
+      p = probe->next_addr();
+    }
+  }
+  return class_was_unloaded;
+}
+
+
+void Dictionary::always_strong_classes_do(OopClosure* blk) {
+  // Follow all system classes and temporary placeholders in dictionary
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry *probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      oop e = probe->klass();
+      oop class_loader = probe->loader();
+      if (is_strongly_reachable(class_loader, e)) {
+        blk->do_oop((oop*)probe->klass_addr());
+        if (class_loader != NULL) {
+          blk->do_oop(probe->loader_addr());
+        }
+        probe->protection_domain_set_oops_do(blk);
+      }
+    }
+  }
+}
+
+
+//   Just the classes from defining class loaders
+void Dictionary::classes_do(void f(klassOop)) {
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      klassOop k = probe->klass();
+      if (probe->loader() == instanceKlass::cast(k)->class_loader()) {
+        f(k);
+      }
+    }
+  }
+}
+
+// Added for initialize_itable_for_klass to handle exceptions
+//   Just the classes from defining class loaders
+void Dictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      klassOop k = probe->klass();
+      if (probe->loader() == instanceKlass::cast(k)->class_loader()) {
+        f(k, CHECK);
+      }
+    }
+  }
+}
+
+
+//   All classes, and their class loaders
+//   (added for helpers that use HandleMarks and ResourceMarks)
+// Don't iterate over placeholders
+void Dictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      klassOop k = probe->klass();
+      f(k, probe->loader(), CHECK);
+    }
+  }
+}
+
+
+//   All classes, and their class loaders
+// Don't iterate over placeholders
+void Dictionary::classes_do(void f(klassOop, oop)) {
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      klassOop k = probe->klass();
+      f(k, probe->loader());
+    }
+  }
+}
+
+
+void Dictionary::oops_do(OopClosure* f) {
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      f->do_oop((oop*)probe->klass_addr());
+      if (probe->loader() != NULL) {
+        f->do_oop(probe->loader_addr());
+      }
+      probe->protection_domain_set_oops_do(f);
+    }
+  }
+}
+
+
+void Dictionary::methods_do(void f(methodOop)) {
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      klassOop k = probe->klass();
+      if (probe->loader() == instanceKlass::cast(k)->class_loader()) {
+        // only take klass is we have the entry with the defining class loader
+        instanceKlass::cast(k)->methods_do(f);
+      }
+    }
+  }
+}
+
+
+klassOop Dictionary::try_get_next_class() {
+  while (true) {
+    if (_current_class_entry != NULL) {
+      klassOop k = _current_class_entry->klass();
+      _current_class_entry = _current_class_entry->next();
+      return k;
+    }
+    _current_class_index = (_current_class_index + 1) % table_size();
+    _current_class_entry = bucket(_current_class_index);
+  }
+  // never reached
+}
+
+
+// Add a loaded class to the system dictionary.
+// Readers of the SystemDictionary aren't always locked, so _buckets
+// is volatile. The store of the next field in the constructor is
+// also cast to volatile;  we do this to ensure store order is maintained
+// by the compilers.
+
+void Dictionary::add_klass(symbolHandle class_name, Handle class_loader,
+                           KlassHandle obj) {
+  assert_locked_or_safepoint(SystemDictionary_lock);
+  assert(obj() != NULL, "adding NULL obj");
+  assert(Klass::cast(obj())->name() == class_name(), "sanity check on name");
+
+  unsigned int hash = compute_hash(class_name, class_loader);
+  int index = hash_to_index(hash);
+  DictionaryEntry* entry = new_entry(hash, obj(), class_loader());
+  add_entry(index, entry);
+}
+
+
+// This routine does not lock the system dictionary.
+//
+// Since readers don't hold a lock, we must make sure that system
+// dictionary entries are only removed at a safepoint (when only one
+// thread is running), and are added to in a safe way (all links must
+// be updated in an MT-safe manner).
+//
+// Callers should be aware that an entry could be added just after
+// _buckets[index] is read here, so the caller will not see the new entry.
+DictionaryEntry* Dictionary::get_entry(int index, unsigned int hash,
+                                       symbolHandle class_name,
+                                       Handle class_loader) {
+  symbolOop name_ = class_name();
+  oop loader_ = class_loader();
+  debug_only(_lookup_count++);
+  for (DictionaryEntry* entry = bucket(index);
+                        entry != NULL;
+                        entry = entry->next()) {
+    if (entry->hash() == hash && entry->equals(name_, loader_)) {
+      return entry;
+    }
+    debug_only(_lookup_length++);
+  }
+  return NULL;
+}
+
+
+klassOop Dictionary::find(int index, unsigned int hash, symbolHandle name,
+                          Handle loader, Handle protection_domain, TRAPS) {
+  DictionaryEntry* entry = get_entry(index, hash, name, loader);
+  if (entry != NULL && entry->is_valid_protection_domain(protection_domain)) {
+    return entry->klass();
+  } else {
+    return NULL;
+  }
+}
+
+
+klassOop Dictionary::find_class(int index, unsigned int hash,
+                                symbolHandle name, Handle loader) {
+  assert_locked_or_safepoint(SystemDictionary_lock);
+  assert (index == index_for(name, loader), "incorrect index?");
+
+  DictionaryEntry* entry = get_entry(index, hash, name, loader);
+  return (entry != NULL) ? entry->klass() : (klassOop)NULL;
+}
+
+
+// Variant of find_class for shared classes.  No locking required, as
+// that table is static.
+
+klassOop Dictionary::find_shared_class(int index, unsigned int hash,
+                                       symbolHandle name) {
+  assert (index == index_for(name, Handle()), "incorrect index?");
+
+  DictionaryEntry* entry = get_entry(index, hash, name, Handle());
+  return (entry != NULL) ? entry->klass() : (klassOop)NULL;
+}
+
+
+void Dictionary::add_protection_domain(int index, unsigned int hash,
+                                       instanceKlassHandle klass,
+                                       Handle loader, Handle protection_domain,
+                                       TRAPS) {
+  symbolHandle klass_name(THREAD, klass->name());
+  DictionaryEntry* entry = get_entry(index, hash, klass_name, loader);
+
+  assert(entry != NULL,"entry must be present, we just created it");
+  assert(protection_domain() != NULL,
+         "real protection domain should be present");
+
+  entry->add_protection_domain(protection_domain());
+
+  assert(entry->contains_protection_domain(protection_domain()),
+         "now protection domain should be present");
+}
+
+
+bool Dictionary::is_valid_protection_domain(int index, unsigned int hash,
+                                            symbolHandle name,
+                                            Handle loader,
+                                            Handle protection_domain) {
+  DictionaryEntry* entry = get_entry(index, hash, name, loader);
+  return entry->is_valid_protection_domain(protection_domain);
+}
+
+
+void Dictionary::reorder_dictionary() {
+
+  // Copy all the dictionary entries into a single master list.
+
+  DictionaryEntry* master_list = NULL;
+  for (int i = 0; i < table_size(); ++i) {
+    DictionaryEntry* p = bucket(i);
+    while (p != NULL) {
+      DictionaryEntry* tmp;
+      tmp = p->next();
+      p->set_next(master_list);
+      master_list = p;
+      p = tmp;
+    }
+    set_entry(i, NULL);
+  }
+
+  // Add the dictionary entries back to the list in the correct buckets.
+  Thread *thread = Thread::current();
+
+  while (master_list != NULL) {
+    DictionaryEntry* p = master_list;
+    master_list = master_list->next();
+    p->set_next(NULL);
+    symbolHandle class_name (thread, instanceKlass::cast((klassOop)(p->klass()))->name());
+    unsigned int hash = compute_hash(class_name, Handle(thread, p->loader()));
+    int index = hash_to_index(hash);
+    p->set_hash(hash);
+    p->set_next(bucket(index));
+    set_entry(index, p);
+  }
+}
+
+
+// ----------------------------------------------------------------------------
+#ifndef PRODUCT
+
+void Dictionary::print() {
+  ResourceMark rm;
+  HandleMark   hm;
+
+  tty->print_cr("Java system dictionary (classes=%d)", number_of_entries());
+  tty->print_cr("^ indicates that initiating loader is different from "
+                "defining loader");
+
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      if (Verbose) tty->print("%4d: ", index);
+      klassOop e = probe->klass();
+      oop class_loader =  probe->loader();
+      bool is_defining_class =
+         (class_loader == instanceKlass::cast(e)->class_loader());
+      tty->print("%s%s", is_defining_class ? " " : "^",
+                   Klass::cast(e)->external_name());
+      if (class_loader != NULL) {
+        tty->print(", loader ");
+        class_loader->print_value();
+      }
+      tty->cr();
+    }
+  }
+}
+
+#endif
+
+void Dictionary::verify() {
+  guarantee(number_of_entries() >= 0, "Verify of system dictionary failed");
+  int element_count = 0;
+  for (int index = 0; index < table_size(); index++) {
+    for (DictionaryEntry* probe = bucket(index);
+                          probe != NULL;
+                          probe = probe->next()) {
+      klassOop e = probe->klass();
+      oop class_loader = probe->loader();
+      guarantee(Klass::cast(e)->oop_is_instance(),
+                              "Verify of system dictionary failed");
+      // class loader must be present;  a null class loader is the
+      // boostrap loader
+      guarantee(class_loader == NULL || class_loader->is_instance(),
+                "checking type of class_loader");
+      e->verify();
+      probe->verify_protection_domain_set();
+      element_count++;
+    }
+  }
+  guarantee(number_of_entries() == element_count,
+            "Verify of system dictionary failed");
+  debug_only(verify_lookup_length((double)number_of_entries() / table_size()));
+}