1 /*
2 * Copyright (c) 2018, 2025, 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 "asm/macroAssembler.inline.hpp"
26 #include "code/SCCache.hpp"
27 #include "gc/shared/barrierSet.hpp"
28 #include "gc/shared/cardTable.hpp"
29 #include "gc/shared/cardTableBarrierSet.hpp"
30 #include "gc/shared/cardTableBarrierSetAssembler.hpp"
31 #include "gc/shared/gc_globals.hpp"
32
33 #define __ masm->
34
35 #ifdef PRODUCT
36 #define BLOCK_COMMENT(str) /* nothing */
37 #else
38 #define BLOCK_COMMENT(str) __ block_comment(str)
39 #endif
40
41 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
42
43 #define TIMES_OOP (UseCompressedOops ? Address::times_4 : Address::times_8)
44
45 void CardTableBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
46 Register addr, Register count, Register tmp) {
47 BarrierSet *bs = BarrierSet::barrier_set();
48 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
49 CardTable* ct = ctbs->card_table();
50 intptr_t byte_map_base = (intptr_t) ct->byte_map_base();
51
52 Label L_loop, L_done;
53 const Register end = count;
54 assert_different_registers(addr, end);
55
56 __ testl(count, count);
57 __ jcc(Assembler::zero, L_done); // zero count - nothing to do
58
59
60 #ifdef _LP64
61 __ leaq(end, Address(addr, count, TIMES_OOP, 0)); // end == addr+count*oop_size
62 __ subptr(end, BytesPerHeapOop); // end - 1 to make inclusive
63 __ shrptr(addr, CardTable::card_shift());
64 __ shrptr(end, CardTable::card_shift());
65 __ subptr(end, addr); // end --> cards count
66
67 if (SCCache::is_on_for_write()) {
68 // SCA needs relocation info for this address
69 __ lea(tmp, ExternalAddress((address)byte_map_base));
70 } else {
71 __ mov64(tmp, byte_map_base);
72 }
73 __ addptr(addr, tmp);
74 __ BIND(L_loop);
75 __ movb(Address(addr, count, Address::times_1), 0);
76 __ decrement(count);
77 __ jcc(Assembler::greaterEqual, L_loop);
78 #else
79 __ lea(end, Address(addr, count, Address::times_ptr, -wordSize));
80 __ shrptr(addr, CardTable::card_shift());
81 __ shrptr(end, CardTable::card_shift());
82 __ subptr(end, addr); // end --> count
83 __ BIND(L_loop);
84 Address cardtable(addr, count, Address::times_1, byte_map_base);
85 __ movb(cardtable, 0);
86 __ decrement(count);
87 __ jcc(Assembler::greaterEqual, L_loop);
88 #endif
89
90 __ BIND(L_done);
91 }
92
93 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst) {
94 // Does a store check for the oop in register obj. The content of
95 // register obj is destroyed afterwards.
96 BarrierSet* bs = BarrierSet::barrier_set();
97
98 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
99 CardTable* ct = ctbs->card_table();
100
101 __ shrptr(obj, CardTable::card_shift());
102
103 Address card_addr;
104
105 // The calculation for byte_map_base is as follows:
106 // byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
107 // So this essentially converts an address to a displacement and it will
108 // never need to be relocated. On 64bit however the value may be too
109 // large for a 32bit displacement.
110 intptr_t byte_map_base = (intptr_t)ct->byte_map_base();
111 if (SCCache::is_on_for_write()) {
112 // SCA needs relocation info for this address
113 ExternalAddress cardtable((address)byte_map_base);
114 Address index(noreg, obj, Address::times_1);
115 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch1);
116 } else
117 if (__ is_simm32(byte_map_base)) {
118 card_addr = Address(noreg, obj, Address::times_1, byte_map_base);
119 } else {
120 // By doing it as an ExternalAddress 'byte_map_base' could be converted to a rip-relative
121 // displacement and done in a single instruction given favorable mapping and a
122 // smarter version of as_Address. However, 'ExternalAddress' generates a relocation
123 // entry and that entry is not properly handled by the relocation code.
124 AddressLiteral cardtable((address)byte_map_base, relocInfo::none);
125 Address index(noreg, obj, Address::times_1);
126 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch1);
127 }
128
129 int dirty = CardTable::dirty_card_val();
130 if (UseCondCardMark) {
131 Label L_already_dirty;
132 __ cmpb(card_addr, dirty);
133 __ jccb(Assembler::equal, L_already_dirty);
134 __ movb(card_addr, dirty);
135 __ bind(L_already_dirty);
136 } else {
137 __ movb(card_addr, dirty);
138 }
139 }
140
141 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
142 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
143 bool in_heap = (decorators & IN_HEAP) != 0;
144
145 bool is_array = (decorators & IS_ARRAY) != 0;
146 bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
147 bool precise = is_array || on_anonymous;
148
149 bool needs_post_barrier = val != noreg && in_heap;
150
151 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, noreg, noreg, noreg);
152 if (needs_post_barrier) {
153 // flatten object address if needed
154 if (!precise || (dst.index() == noreg && dst.disp() == 0)) {
155 store_check(masm, dst.base(), dst);
156 } else {
157 __ lea(tmp1, dst);
158 store_check(masm, tmp1, dst);
159 }
160 }
161 }