| /* |
| * Copyright (c) 1997, 2018, 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/javaClasses.hpp" |
| #include "classfile/systemDictionary.hpp" |
| #include "oops/instanceRefKlass.inline.hpp" |
| #include "oops/oop.inline.hpp" |
| |
| void InstanceRefKlass::update_nonstatic_oop_maps(Klass* k) { |
| // Clear the nonstatic oop-map entries corresponding to referent |
| // and discovered fields. They are treated specially by the |
| // garbage collector. |
| InstanceKlass* ik = InstanceKlass::cast(k); |
| |
| // Check that we have the right class |
| debug_only(static bool first_time = true); |
| assert(k == SystemDictionary::Reference_klass() && first_time, |
| "Invalid update of maps"); |
| debug_only(first_time = false); |
| assert(ik->nonstatic_oop_map_count() == 1, "just checking"); |
| |
| OopMapBlock* map = ik->start_of_nonstatic_oop_maps(); |
| |
| #ifdef ASSERT |
| // Verify fields are in the expected places. |
| int referent_offset = java_lang_ref_Reference::referent_offset; |
| int queue_offset = java_lang_ref_Reference::queue_offset; |
| int next_offset = java_lang_ref_Reference::next_offset; |
| int discovered_offset = java_lang_ref_Reference::discovered_offset; |
| assert(referent_offset < queue_offset, "just checking"); |
| assert(queue_offset < next_offset, "just checking"); |
| assert(next_offset < discovered_offset, "just checking"); |
| const unsigned int count = |
| 1 + ((discovered_offset - referent_offset) / heapOopSize); |
| assert(count == 4, "just checking"); |
| #endif // ASSERT |
| |
| // Updated map starts at "queue", covers "queue" and "next". |
| const int new_offset = java_lang_ref_Reference::queue_offset; |
| const unsigned int new_count = 2; // queue and next |
| |
| // Verify existing map is as expected, and update if needed. |
| if (UseSharedSpaces) { |
| assert(map->offset() == new_offset, "just checking"); |
| assert(map->count() == new_count, "just checking"); |
| } else { |
| assert(map->offset() == referent_offset, "just checking"); |
| assert(map->count() == count, "just checking"); |
| map->set_offset(new_offset); |
| map->set_count(new_count); |
| } |
| } |
| |
| |
| // Verification |
| |
| void InstanceRefKlass::oop_verify_on(oop obj, outputStream* st) { |
| InstanceKlass::oop_verify_on(obj, st); |
| // Verify referent field |
| oop referent = java_lang_ref_Reference::referent(obj); |
| if (referent != NULL) { |
| guarantee(oopDesc::is_oop(referent), "referent field heap failed"); |
| } |
| // Additional verification for next field, which must be a Reference or null |
| oop next = java_lang_ref_Reference::next(obj); |
| if (next != NULL) { |
| guarantee(oopDesc::is_oop(next), "next field should be an oop"); |
| guarantee(next->is_instance(), "next field should be an instance"); |
| guarantee(InstanceKlass::cast(next->klass())->is_reference_instance_klass(), "next field verify failed"); |
| } |
| } |