Mercurial > hg > graal-compiler
view src/share/vm/classfile/dictionary.cpp @ 3405:8cbcd406c42e
7042740: CMS: assert(n> q) failed: Looping at: ... blockOffsetTable.cpp:557
Summary: Do a one-step look-ahead, when sweeping free or garbage blocks, to avoid overstepping sweep limit, which may become a non-block-boundary because of a heap expansion delta coalescing with a previously co-terminal free block.
Reviewed-by: brutisso, tonyp
author | ysr |
---|---|
date | Fri, 27 May 2011 15:05:33 -0700 |
parents | 1d1603768966 |
children | b2cd0ee8f778 |
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/* * Copyright (c) 2003, 2011, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "classfile/dictionary.hpp" #include "classfile/systemDictionary.hpp" #include "oops/oop.inline.hpp" #include "prims/jvmtiRedefineClassesTrace.hpp" #include "services/classLoadingService.hpp" #include "utilities/hashtable.inline.hpp" DictionaryEntry* Dictionary::_current_class_entry = NULL; int Dictionary::_current_class_index = 0; Dictionary::Dictionary(int table_size) : TwoOopHashtable<klassOop>(table_size, sizeof(DictionaryEntry)) { _current_class_index = 0; _current_class_entry = NULL; }; Dictionary::Dictionary(int table_size, HashtableBucket* t, int number_of_entries) : TwoOopHashtable<klassOop>(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<klassOop>::new_entry(hash, klass); entry->set_loader(loader); entry->set_pd_set(NULL); return entry; } DictionaryEntry* Dictionary::new_entry() { DictionaryEntry* entry = (DictionaryEntry*)Hashtable<klassOop>::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<klassOop>::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); jobject cp_ref = pv_node->prev_constant_pool(); assert(cp_ref != NULL, "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()) { klassOop 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(Symbol* 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, Symbol* class_name, Handle class_loader) { oop loader = class_loader(); debug_only(_lookup_count++); for (DictionaryEntry* entry = bucket(index); entry != NULL; entry = entry->next()) { if (entry->hash() == hash && entry->equals(class_name, loader)) { return entry; } debug_only(_lookup_length++); } return NULL; } klassOop Dictionary::find(int index, unsigned int hash, Symbol* 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, Symbol* 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, Symbol* 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) { Symbol* klass_name = 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, Symbol* 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); Symbol* class_name = 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); } } SymbolPropertyTable::SymbolPropertyTable(int table_size) : Hashtable<Symbol*>(table_size, sizeof(SymbolPropertyEntry)) { } SymbolPropertyTable::SymbolPropertyTable(int table_size, HashtableBucket* t, int number_of_entries) : Hashtable<Symbol*>(table_size, sizeof(SymbolPropertyEntry), t, number_of_entries) { } SymbolPropertyEntry* SymbolPropertyTable::find_entry(int index, unsigned int hash, Symbol* sym, intptr_t sym_mode) { assert(index == index_for(sym, sym_mode), "incorrect index?"); for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) { if (p->hash() == hash && p->symbol() == sym && p->symbol_mode() == sym_mode) { return p; } } return NULL; } SymbolPropertyEntry* SymbolPropertyTable::add_entry(int index, unsigned int hash, Symbol* sym, intptr_t sym_mode) { assert_locked_or_safepoint(SystemDictionary_lock); assert(index == index_for(sym, sym_mode), "incorrect index?"); assert(find_entry(index, hash, sym, sym_mode) == NULL, "no double entry"); SymbolPropertyEntry* p = new_entry(hash, sym, sym_mode); Hashtable<Symbol*>::add_entry(index, p); return p; } void SymbolPropertyTable::oops_do(OopClosure* f) { for (int index = 0; index < table_size(); index++) { for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) { if (p->property_oop() != NULL) { f->do_oop(p->property_oop_addr()); } } } } void SymbolPropertyTable::methods_do(void f(methodOop)) { for (int index = 0; index < table_size(); index++) { for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) { oop prop = p->property_oop(); if (prop != NULL && prop->is_method()) { f((methodOop)prop); } } } } // ---------------------------------------------------------------------------- #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())); }