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 "gc/shared/barrierSet.hpp"
27 #include "gc/shared/cardTable.hpp"
28 #include "gc/shared/cardTableBarrierSet.hpp"
29 #include "gc/shared/cardTableBarrierSetAssembler.hpp"
30 #include "gc/shared/gc_globals.hpp"
31
32 #define __ masm->
33
34 #ifdef PRODUCT
35 #define BLOCK_COMMENT(str) /* nothing */
36 #else
37 #define BLOCK_COMMENT(str) __ block_comment(str)
38 #endif
39
40 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
41
42 #define TIMES_OOP (UseCompressedOops ? Address::times_4 : Address::times_8)
43
44 void CardTableBarrierSetAssembler::arraycopy_prologue(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
45 Register src, Register dst, Register count) {
46 bool checkcast = (decorators & ARRAYCOPY_CHECKCAST) != 0;
47 bool disjoint = (decorators & ARRAYCOPY_DISJOINT) != 0;
48 bool obj_int = (type == T_OBJECT) && UseCompressedOops;
49
50 if (is_reference_type(type)) {
51 if (!checkcast) {
52 if (!obj_int) {
53 // Save count for barrier
54 __ movptr(r11, count);
55 } else if (disjoint) {
56 // Save dst in r11 in the disjoint case
57 __ movq(r11, dst);
58 }
59 }
60 gen_write_ref_array_pre_barrier(masm, decorators, dst, count);
61 }
62 }
63
64 void CardTableBarrierSetAssembler::arraycopy_epilogue(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
65 Register src, Register dst, Register count) {
66 bool checkcast = (decorators & ARRAYCOPY_CHECKCAST) != 0;
67 bool disjoint = (decorators & ARRAYCOPY_DISJOINT) != 0;
68 bool obj_int = (type == T_OBJECT) && UseCompressedOops;
69 Register tmp = rax;
70
71 if (is_reference_type(type)) {
72 if (!checkcast) {
73 if (!obj_int) {
74 // Save count for barrier
75 count = r11;
76 } else if (disjoint) {
77 // Use the saved dst in the disjoint case
78 dst = r11;
79 }
80 } else {
81 tmp = rscratch1;
82 }
83 gen_write_ref_array_post_barrier(masm, decorators, dst, count, tmp);
84 }
85 }
86
87 void CardTableBarrierSetAssembler::store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
88 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
89 if (is_reference_type(type)) {
90 oop_store_at(masm, decorators, type, dst, val, tmp1, tmp2, tmp3);
91 } else {
92 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, tmp1, tmp2, tmp3);
93 }
94 }
95
96 void CardTableBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
97 Register addr, Register count, Register tmp) {
98 CardTableBarrierSet* ctbs = CardTableBarrierSet::barrier_set();
99
100 Label L_loop, L_done;
101 const Register end = count;
102 assert_different_registers(addr, end);
103
104 __ testl(count, count);
105 __ jcc(Assembler::zero, L_done); // zero count - nothing to do
106
107
108 __ leaq(end, Address(addr, count, TIMES_OOP, 0)); // end == addr+count*oop_size
109 __ subptr(end, BytesPerHeapOop); // end - 1 to make inclusive
110 __ shrptr(addr, CardTable::card_shift());
111 __ shrptr(end, CardTable::card_shift());
112 __ subptr(end, addr); // end --> cards count
113
114 __ mov64(tmp, (intptr_t)ctbs->card_table_base_const());
115 __ addptr(addr, tmp);
116 __ BIND(L_loop);
117 __ movb(Address(addr, count, Address::times_1), 0);
118 __ decrement(count);
119 __ jcc(Assembler::greaterEqual, L_loop);
120
121 __ BIND(L_done);
122 }
123
124 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst) {
125 // Does a store check for the oop in register obj. The content of
126 // register obj is destroyed afterwards.
127 CardTableBarrierSet* ctbs = CardTableBarrierSet::barrier_set();
128
129 __ shrptr(obj, CardTable::card_shift());
130
131 Address card_addr;
132
133 // The calculation for byte_map_base is as follows:
134 // byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
135 // So this essentially converts an address to a displacement and it will
136 // never need to be relocated. On 64bit however the value may be too
137 // large for a 32bit displacement.
138 intptr_t byte_map_base = (intptr_t)ctbs->card_table_base_const();
139 if (__ is_simm32(byte_map_base)) {
140 card_addr = Address(noreg, obj, Address::times_1, byte_map_base);
141 } else {
142 // By doing it as an ExternalAddress 'byte_map_base' could be converted to a rip-relative
143 // displacement and done in a single instruction given favorable mapping and a
144 // smarter version of as_Address. However, 'ExternalAddress' generates a relocation
145 // entry and that entry is not properly handled by the relocation code.
146 AddressLiteral cardtable((address)byte_map_base, relocInfo::none);
147 Address index(noreg, obj, Address::times_1);
148 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch1);
149 }
150
151 int dirty = CardTable::dirty_card_val();
152 if (UseCondCardMark) {
153 Label L_already_dirty;
154 __ cmpb(card_addr, dirty);
155 __ jccb(Assembler::equal, L_already_dirty);
156 __ movb(card_addr, dirty);
157 __ bind(L_already_dirty);
158 } else {
159 __ movb(card_addr, dirty);
160 }
161 }
162
163 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
164 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
165 bool in_heap = (decorators & IN_HEAP) != 0;
166
167 bool is_array = (decorators & IS_ARRAY) != 0;
168 bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
169 bool precise = is_array || on_anonymous;
170
171 bool needs_post_barrier = val != noreg && in_heap;
172
173 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, noreg, noreg, noreg);
174 if (needs_post_barrier) {
175 // flatten object address if needed
176 if (!precise || (dst.index() == noreg && dst.disp() == 0)) {
177 store_check(masm, dst.base(), dst);
178 } else {
179 __ lea(tmp1, dst);
180 store_check(masm, tmp1, dst);
181 }
182 }
183 }