1/*
2 * Copyright (c) 2016, 2017, 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#include "precompiled.hpp"
26#include "asm/macroAssembler.hpp"
27#include "runtime/sharedRuntime.hpp"
28#include "vmreg_x86.inline.hpp"
29#ifdef COMPILER1
30#include "c1/c1_Runtime1.hpp"
31#endif //COMPILER1
32
33#define __ masm->
34
35#ifdef COMPILER1
36// ---------------------------------------------------------------------------
37// Object.hashCode, System.identityHashCode can pull the hashCode from the
38// header word instead of doing a full VM transition once it's been computed.
39// Since hashCode is usually polymorphic at call sites we can't do this
40// optimization at the call site without a lot of work.
41void SharedRuntime::inline_check_hashcode_from_object_header(MacroAssembler* masm,
42                                 const methodHandle& method,
43                                 Register obj_reg,
44                                 Register result) {
45  Label slowCase;
46
47  // Unlike for Object.hashCode, System.identityHashCode is static method and
48  // gets object as argument instead of the receiver.
49  if (method->intrinsic_id() == vmIntrinsics::_identityHashCode) {
50    Label Continue;
51    // return 0 for null reference input
52    __ cmpptr(obj_reg, (int32_t)NULL_WORD);
53    __ jcc(Assembler::notEqual, Continue);
54    __ xorptr(result, result);
55    __ ret(0);
56    __ bind(Continue);
57  }
58
59  __ movptr(result, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
60
61  // check if locked
62  __ testptr(result, markOopDesc::unlocked_value);
63  __ jcc(Assembler::zero, slowCase);
64
65  if (UseBiasedLocking) {
66    // Check if biased and fall through to runtime if so
67    __ testptr(result, markOopDesc::biased_lock_bit_in_place);
68    __ jcc(Assembler::notZero, slowCase);
69  }
70
71  // get hash
72#ifdef _LP64
73  // Read the header and build a mask to get its hash field.
74  // Depend on hash_mask being at most 32 bits and avoid the use of hash_mask_in_place
75  // because it could be larger than 32 bits in a 64-bit vm. See markOop.hpp.
76  __ shrptr(result, markOopDesc::hash_shift);
77  __ andptr(result, markOopDesc::hash_mask);
78#else
79  __ andptr(result, markOopDesc::hash_mask_in_place);
80#endif //_LP64
81
82  // test if hashCode exists
83  __ jcc(Assembler::zero, slowCase);
84#ifndef _LP64
85  __ shrptr(result, markOopDesc::hash_shift);
86#endif
87  __ ret(0);
88  __ bind(slowCase);
89}
90#endif //COMPILER1
91
92