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/compressedKlass.inline.hpp" 29 #include "oops/compressedOops.inline.hpp" 30 #include "oops/markWord.hpp" 31 #include "runtime/safepoint.hpp" 32 33 #ifdef _LP64 34 narrowKlass markWord::narrow_klass() const { 35 return narrowKlass(value() >> klass_shift); 36 } 37 38 Klass* markWord::klass() const { 39 assert(UseCompactObjectHeaders, "only used with compact object headers"); 40 assert(!CompressedKlassPointers::is_null(narrow_klass()), "narrow klass must not be null: " INTPTR_FORMAT, value()); 41 return CompressedKlassPointers::decode_not_null(narrow_klass()); 42 } 43 44 Klass* markWord::klass_or_null() const { 45 assert(UseCompactObjectHeaders, "only used with compact object headers"); 46 return CompressedKlassPointers::decode(narrow_klass()); 47 } 48 49 markWord markWord::set_narrow_klass(const narrowKlass nklass) const { 50 assert(UseCompactObjectHeaders, "only used with compact object headers"); 51 return markWord((value() & ~klass_mask_in_place) | ((uintptr_t) nklass << klass_shift)); 52 } 53 54 Klass* markWord::safe_klass() const { 55 assert(UseCompactObjectHeaders, "only used with compact object headers"); 56 assert(SafepointSynchronize::is_at_safepoint(), "only call at safepoint"); 57 markWord m = *this; 58 if (m.has_displaced_mark_helper()) { 59 m = m.displaced_mark_helper(); 60 } 61 return CompressedKlassPointers::decode_not_null(m.narrow_klass()); 62 } 63 64 markWord markWord::set_klass(const Klass* klass) const { 65 assert(UseCompactObjectHeaders, "only used with compact object headers"); 66 assert(UseCompressedClassPointers, "expect compressed klass pointers"); 67 // TODO: Don't cast to non-const, change CKP::encode() to accept const Klass* instead. 68 narrowKlass nklass = CompressedKlassPointers::encode(const_cast<Klass*>(klass)); 69 return set_narrow_klass(nklass); 70 } 71 #endif 72 73 #endif // SHARE_OOPS_MARKWORD_INLINE_HPP