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 BarrierSet *bs = BarrierSet::barrier_set();
99 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
100 CardTable* ct = ctbs->card_table();
101 intptr_t disp = (intptr_t) ct->byte_map_base();
102 SHENANDOAHGC_ONLY(assert(!UseShenandoahGC, "Shenandoah byte_map_base is not constant.");)
103
104 Label L_loop, L_done;
105 const Register end = count;
106 assert_different_registers(addr, end);
107
108 __ testl(count, count);
109 __ jcc(Assembler::zero, L_done); // zero count - nothing to do
110
111
112 __ leaq(end, Address(addr, count, TIMES_OOP, 0)); // end == addr+count*oop_size
113 __ subptr(end, BytesPerHeapOop); // end - 1 to make inclusive
114 __ shrptr(addr, CardTable::card_shift());
115 __ shrptr(end, CardTable::card_shift());
116 __ subptr(end, addr); // end --> cards count
117
118 __ mov64(tmp, disp);
119 __ addptr(addr, tmp);
120 __ BIND(L_loop);
121 __ movb(Address(addr, count, Address::times_1), 0);
122 __ decrement(count);
123 __ jcc(Assembler::greaterEqual, L_loop);
124
125 __ BIND(L_done);
126 }
127
128 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst) {
129 // Does a store check for the oop in register obj. The content of
130 // register obj is destroyed afterwards.
131 BarrierSet* bs = BarrierSet::barrier_set();
132
133 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
134 CardTable* ct = ctbs->card_table();
135
136 __ shrptr(obj, CardTable::card_shift());
137
138 Address card_addr;
139
140 // The calculation for byte_map_base is as follows:
141 // byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
142 // So this essentially converts an address to a displacement and it will
143 // never need to be relocated. On 64bit however the value may be too
144 // large for a 32bit displacement.
145 intptr_t byte_map_base = (intptr_t)ct->byte_map_base();
146 if (__ is_simm32(byte_map_base)) {
147 card_addr = Address(noreg, obj, Address::times_1, byte_map_base);
148 } else {
149 // By doing it as an ExternalAddress 'byte_map_base' could be converted to a rip-relative
150 // displacement and done in a single instruction given favorable mapping and a
151 // smarter version of as_Address. However, 'ExternalAddress' generates a relocation
152 // entry and that entry is not properly handled by the relocation code.
153 AddressLiteral cardtable((address)byte_map_base, relocInfo::none);
154 Address index(noreg, obj, Address::times_1);
155 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch1);
156 }
157
158 int dirty = CardTable::dirty_card_val();
159 if (UseCondCardMark) {
160 Label L_already_dirty;
161 __ cmpb(card_addr, dirty);
162 __ jccb(Assembler::equal, L_already_dirty);
163 __ movb(card_addr, dirty);
164 __ bind(L_already_dirty);
165 } else {
166 __ movb(card_addr, dirty);
167 }
168 }
169
170 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
171 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
172 bool in_heap = (decorators & IN_HEAP) != 0;
173
174 bool is_array = (decorators & IS_ARRAY) != 0;
175 bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
176 bool precise = is_array || on_anonymous;
177
178 bool needs_post_barrier = val != noreg && in_heap;
179
180 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, noreg, noreg, noreg);
181 if (needs_post_barrier) {
182 // flatten object address if needed
183 if (!precise || (dst.index() == noreg && dst.disp() == 0)) {
184 store_check(masm, dst.base(), dst);
185 } else {
186 __ lea(tmp1, dst);
187 store_check(masm, tmp1, dst);
188 }
189 }
190 }