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 "utilities/globalDefinitions.hpp"
29 #include "vmreg_x86.inline.hpp"
30 #ifdef COMPILER1
31 #include "c1/c1_Runtime1.hpp"
32 #endif //COMPILER1
33
34 #define __ masm->
35
36 #ifdef COMPILER1
37 // ---------------------------------------------------------------------------
38 // Object.hashCode, System.identityHashCode can pull the hashCode from the
39 // header word instead of doing a full VM transition once it's been computed.
40 // Since hashCode is usually polymorphic at call sites we can't do this
41 // optimization at the call site without a lot of work.
42 void SharedRuntime::inline_check_hashcode_from_object_header(MacroAssembler* masm,
43 const methodHandle& method,
44 Register obj_reg,
45 Register result) {
46 Label slowCase;
47
48 // Unlike for Object.hashCode, System.identityHashCode is static method and
49 // gets object as argument instead of the receiver.
50 if (method->intrinsic_id() == vmIntrinsics::_identityHashCode) {
51 Label Continue;
52 // return 0 for null reference input
53 __ cmpptr(obj_reg, (int32_t)NULL_WORD);
54 __ jcc(Assembler::notEqual, Continue);
55 __ xorptr(result, result);
56 __ ret(0);
57 __ bind(Continue);
58 }
59
60 __ movptr(result, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
61
62
63 if (LockingMode == LM_LIGHTWEIGHT) {
64 // check if monitor
65 __ testptr(result, markWord::monitor_value);
66 __ jcc(Assembler::notZero, slowCase);
67 } else {
68 // check if locked
69 __ testptr(result, markWord::unlocked_value);
70 __ jcc(Assembler::zero, slowCase);
71 }
72
73 if (UseBiasedLocking) {
74 // Check if biased and fall through to runtime if so
75 __ testptr(result, markWord::biased_lock_bit_in_place);
76 __ jcc(Assembler::notZero, slowCase);
77 }
78
79 // get hash
80 #ifdef _LP64
81 // Read the header and build a mask to get its hash field.
82 // Depend on hash_mask being at most 32 bits and avoid the use of hash_mask_in_place
83 // because it could be larger than 32 bits in a 64-bit vm. See markWord.hpp.
84 if (UseCompactObjectHeaders) {
85 __ shrptr(result, markWord::hash_shift_compact);
86 __ andptr(result, markWord::hash_mask_compact);
87 } else {
88 __ shrptr(result, markWord::hash_shift);
89 __ andptr(result, markWord::hash_mask);
90 }
91 #else
92 __ andptr(result, markWord::hash_mask_in_place);
93 #endif //_LP64
94
95 // test if hashCode exists
96 __ jcc(Assembler::zero, slowCase);
97 #ifndef _LP64
98 __ shrptr(result, markWord::hash_shift);
99 #endif
100 __ ret(0);
101 __ bind(slowCase);
102 }
103 #endif //COMPILER1
104