1 /* 2 * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_OOPS_MARKWORD_INLINE_HPP 26 #define SHARE_OOPS_MARKWORD_INLINE_HPP 27 28 #include "oops/compressedOops.inline.hpp" 29 #include "oops/markWord.hpp" 30 #include "runtime/safepoint.hpp" 31 32 #ifdef _LP64 33 narrowKlass markWord::narrow_klass() const { 34 return narrowKlass(value() >> klass_shift); 35 } 36 37 Klass* markWord::klass() const { 38 assert(UseCompactObjectHeaders, "only used with compact object headers"); 39 assert(!CompressedKlassPointers::is_null(narrow_klass()), "narrow klass must not be null: " INTPTR_FORMAT, value()); 40 return CompressedKlassPointers::decode_not_null(narrow_klass()); 41 } 42 43 Klass* markWord::klass_or_null() const { 44 assert(UseCompactObjectHeaders, "only used with compact object headers"); 45 return CompressedKlassPointers::decode(narrow_klass()); 46 } 47 48 markWord markWord::set_narrow_klass(const narrowKlass nklass) const { 49 assert(UseCompactObjectHeaders, "only used with compact object headers"); 50 return markWord((value() & ~klass_mask_in_place) | ((uintptr_t) nklass << klass_shift)); 51 } 52 53 Klass* markWord::safe_klass() const { 54 assert(UseCompactObjectHeaders, "only used with compact object headers"); 55 assert(SafepointSynchronize::is_at_safepoint(), "only call at safepoint"); 56 markWord m = *this; 57 if (m.has_displaced_mark_helper()) { 58 m = m.displaced_mark_helper(); 59 } 60 return CompressedKlassPointers::decode_not_null(m.narrow_klass()); 61 } 62 63 markWord markWord::set_klass(const Klass* klass) const { 64 assert(UseCompactObjectHeaders, "only used with compact object headers"); 65 assert(UseCompressedClassPointers, "expect compressed klass pointers"); 66 // TODO: Don't cast to non-const, change CKP::encode() to accept const Klass* instead. 67 narrowKlass nklass = CompressedKlassPointers::encode(const_cast<Klass*>(klass)); 68 return set_narrow_klass(nklass); 69 } 70 #endif 71 72 #endif // SHARE_OOPS_MARKWORD_INLINE_HPP