Mercurial > hg > truffle
view src/share/vm/oops/arrayKlass.cpp @ 452:00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery.
Reviewed-by: apetrusenko, jcoomes
author | ysr |
---|---|
date | Thu, 20 Nov 2008 12:27:41 -0800 |
parents | a61af66fc99e |
children | 1413494da700 |
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/* * 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. * */ # include "incls/_precompiled.incl" # include "incls/_arrayKlass.cpp.incl" int arrayKlass::object_size(int header_size) const { // size of an array klass object assert(header_size <= instanceKlass::header_size(), "bad header size"); // If this assert fails, see comments in base_create_array_klass. header_size = instanceKlass::header_size(); #ifdef _LP64 int size = header_size + align_object_offset(vtable_length()); #else int size = header_size + vtable_length(); #endif return align_object_size(size); } klassOop arrayKlass::java_super() const { if (super() == NULL) return NULL; // bootstrap case // Array klasses have primary supertypes which are not reported to Java. // Example super chain: String[][] -> Object[][] -> Object[] -> Object return SystemDictionary::object_klass(); } oop arrayKlass::multi_allocate(int rank, jint* sizes, TRAPS) { ShouldNotReachHere(); return NULL; } methodOop arrayKlass::uncached_lookup_method(symbolOop name, symbolOop signature) const { // There are no methods in an array klass but the super class (Object) has some assert(super(), "super klass must be present"); return Klass::cast(super())->uncached_lookup_method(name, signature); } arrayKlassHandle arrayKlass::base_create_array_klass( const Klass_vtbl& cplusplus_vtbl, int header_size, KlassHandle klass, TRAPS) { // Allocation // Note: because the Java vtable must start at the same offset in all klasses, // we must insert filler fields into arrayKlass to make it the same size as instanceKlass. // If this assert fails, add filler to instanceKlass to make it bigger. assert(header_size <= instanceKlass::header_size(), "array klasses must be same size as instanceKlass"); header_size = instanceKlass::header_size(); // Arrays don't add any new methods, so their vtable is the same size as // the vtable of klass Object. int vtable_size = Universe::base_vtable_size(); arrayKlassHandle k; KlassHandle base_klass = Klass::base_create_klass(klass, header_size + vtable_size, cplusplus_vtbl, CHECK_(k)); // No safepoint should be possible until the handle's // target below becomes parsable No_Safepoint_Verifier no_safepoint; k = arrayKlassHandle(THREAD, base_klass()); assert(!k()->is_parsable(), "not expecting parsability yet."); k->set_super(Universe::is_bootstrapping() ? (klassOop)NULL : SystemDictionary::object_klass()); k->set_layout_helper(Klass::_lh_neutral_value); k->set_dimension(1); k->set_higher_dimension(NULL); k->set_lower_dimension(NULL); k->set_component_mirror(NULL); k->set_vtable_length(vtable_size); k->set_is_cloneable(); // All arrays are considered to be cloneable (See JLS 20.1.5) assert(k()->is_parsable(), "should be parsable here."); // Make sure size calculation is right assert(k()->size() == align_object_size(header_size + vtable_size), "wrong size for object"); return k; } // Initialization of vtables and mirror object is done separatly from base_create_array_klass, // since a GC can happen. At this point all instance variables of the arrayKlass must be setup. void arrayKlass::complete_create_array_klass(arrayKlassHandle k, KlassHandle super_klass, TRAPS) { ResourceMark rm(THREAD); k->initialize_supers(super_klass(), CHECK); k->vtable()->initialize_vtable(false, CHECK); java_lang_Class::create_mirror(k, CHECK); } objArrayOop arrayKlass::compute_secondary_supers(int num_extra_slots, TRAPS) { // interfaces = { cloneable_klass, serializable_klass }; assert(num_extra_slots == 0, "sanity of primitive array type"); // Must share this for correct bootstrapping! return Universe::the_array_interfaces_array(); } bool arrayKlass::compute_is_subtype_of(klassOop k) { // An array is a subtype of Serializable, Clonable, and Object return k == SystemDictionary::object_klass() || k == SystemDictionary::cloneable_klass() || k == SystemDictionary::serializable_klass(); } inline intptr_t* arrayKlass::start_of_vtable() const { // all vtables start at the same place, that's why we use instanceKlass::header_size here return ((intptr_t*)as_klassOop()) + instanceKlass::header_size(); } klassVtable* arrayKlass::vtable() const { KlassHandle kh(Thread::current(), as_klassOop()); return new klassVtable(kh, start_of_vtable(), vtable_length() / vtableEntry::size()); } objArrayOop arrayKlass::allocate_arrayArray(int n, int length, TRAPS) { if (length < 0) { THROW_0(vmSymbols::java_lang_NegativeArraySizeException()); } if (length > arrayOopDesc::max_array_length(T_ARRAY)) { THROW_OOP_0(Universe::out_of_memory_error_array_size()); } int size = objArrayOopDesc::object_size(length); klassOop k = array_klass(n+dimension(), CHECK_0); arrayKlassHandle ak (THREAD, k); objArrayOop o = (objArrayOop)CollectedHeap::array_allocate(ak, size, length, CHECK_0); // initialization to NULL not necessary, area already cleared return o; } void arrayKlass::array_klasses_do(void f(klassOop k)) { klassOop k = as_klassOop(); // Iterate over this array klass and all higher dimensions while (k != NULL) { f(k); k = arrayKlass::cast(k)->higher_dimension(); } } void arrayKlass::with_array_klasses_do(void f(klassOop k)) { array_klasses_do(f); } // JVM support jint arrayKlass::compute_modifier_flags(TRAPS) const { return JVM_ACC_ABSTRACT | JVM_ACC_FINAL | JVM_ACC_PUBLIC; } // JVMTI support jint arrayKlass::jvmti_class_status() const { return JVMTI_CLASS_STATUS_ARRAY; } #ifndef PRODUCT // Printing void arrayKlass::oop_print_on(oop obj, outputStream* st) { assert(obj->is_array(), "must be array"); Klass::oop_print_on(obj, st); st->print_cr(" - length: %d", arrayOop(obj)->length()); } #endif // Verification void arrayKlass::oop_verify_on(oop obj, outputStream* st) { guarantee(obj->is_array(), "must be array"); arrayOop a = arrayOop(obj); guarantee(a->length() >= 0, "array with negative length?"); }