94 lines
3.7 KiB
C++
94 lines
3.7 KiB
C++
/*
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* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "classfile/javaClasses.hpp"
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#include "classfile/systemDictionary.hpp"
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#include "oops/instanceRefKlass.inline.hpp"
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#include "oops/oop.inline.hpp"
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void InstanceRefKlass::update_nonstatic_oop_maps(Klass* k) {
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// Clear the nonstatic oop-map entries corresponding to referent
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// and discovered fields. They are treated specially by the
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// garbage collector.
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InstanceKlass* ik = InstanceKlass::cast(k);
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// Check that we have the right class
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debug_only(static bool first_time = true);
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assert(k == SystemDictionary::Reference_klass() && first_time,
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"Invalid update of maps");
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debug_only(first_time = false);
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assert(ik->nonstatic_oop_map_count() == 1, "just checking");
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OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
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#ifdef ASSERT
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// Verify fields are in the expected places.
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int referent_offset = java_lang_ref_Reference::referent_offset;
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int queue_offset = java_lang_ref_Reference::queue_offset;
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int next_offset = java_lang_ref_Reference::next_offset;
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int discovered_offset = java_lang_ref_Reference::discovered_offset;
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assert(referent_offset < queue_offset, "just checking");
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assert(queue_offset < next_offset, "just checking");
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assert(next_offset < discovered_offset, "just checking");
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const unsigned int count =
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1 + ((discovered_offset - referent_offset) / heapOopSize);
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assert(count == 4, "just checking");
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#endif // ASSERT
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// Updated map starts at "queue", covers "queue" and "next".
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const int new_offset = java_lang_ref_Reference::queue_offset;
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const unsigned int new_count = 2; // queue and next
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// Verify existing map is as expected, and update if needed.
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if (UseSharedSpaces) {
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assert(map->offset() == new_offset, "just checking");
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assert(map->count() == new_count, "just checking");
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} else {
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assert(map->offset() == referent_offset, "just checking");
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assert(map->count() == count, "just checking");
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map->set_offset(new_offset);
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map->set_count(new_count);
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}
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}
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// Verification
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void InstanceRefKlass::oop_verify_on(oop obj, outputStream* st) {
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InstanceKlass::oop_verify_on(obj, st);
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// Verify referent field
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oop referent = java_lang_ref_Reference::referent(obj);
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if (referent != NULL) {
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guarantee(oopDesc::is_oop(referent), "referent field heap failed");
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}
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// Additional verification for next field, which must be a Reference or null
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oop next = java_lang_ref_Reference::next(obj);
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if (next != NULL) {
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guarantee(oopDesc::is_oop(next), "next field should be an oop");
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guarantee(next->is_instance(), "next field should be an instance");
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guarantee(InstanceKlass::cast(next->klass())->is_reference_instance_klass(), "next field verify failed");
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}
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}
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