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/aotCodeCache.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 SHENANDOAHGC_ONLY(assert(!UseShenandoahGC, "Shenandoah byte_map_base is not constant.");)
52
53 Label L_loop, L_done;
54 const Register end = count;
55 assert_different_registers(addr, end);
56
57 __ testl(count, count);
58 __ jcc(Assembler::zero, L_done); // zero count - nothing to do
59
60
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 (AOTCodeCache::is_on_for_dump()) {
68 // AOT code 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
79 __ BIND(L_done);
80 }
81
82 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst) {
83 // Does a store check for the oop in register obj. The content of
84 // register obj is destroyed afterwards.
85 BarrierSet* bs = BarrierSet::barrier_set();
86
87 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
88 CardTable* ct = ctbs->card_table();
89
90 __ shrptr(obj, CardTable::card_shift());
91
92 Address card_addr;
93
94 // The calculation for byte_map_base is as follows:
95 // byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
96 // So this essentially converts an address to a displacement and it will
97 // never need to be relocated. On 64bit however the value may be too
98 // large for a 32bit displacement.
99 intptr_t byte_map_base = (intptr_t)ct->byte_map_base();
100 if (AOTCodeCache::is_on_for_dump()) {
101 // AOT code needs relocation info for this address
102 ExternalAddress cardtable((address)byte_map_base);
103 Address index(noreg, obj, Address::times_1);
104 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch1);
105 } else
106 if (__ is_simm32(byte_map_base)) {
107 card_addr = Address(noreg, obj, Address::times_1, byte_map_base);
108 } else {
109 // By doing it as an ExternalAddress 'byte_map_base' could be converted to a rip-relative
110 // displacement and done in a single instruction given favorable mapping and a
111 // smarter version of as_Address. However, 'ExternalAddress' generates a relocation
112 // entry and that entry is not properly handled by the relocation code.
113 AddressLiteral cardtable((address)byte_map_base, relocInfo::none);
114 Address index(noreg, obj, Address::times_1);
115 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch1);
116 }
117
118 int dirty = CardTable::dirty_card_val();
119 if (UseCondCardMark) {
120 Label L_already_dirty;
121 __ cmpb(card_addr, dirty);
122 __ jccb(Assembler::equal, L_already_dirty);
123 __ movb(card_addr, dirty);
124 __ bind(L_already_dirty);
125 } else {
126 __ movb(card_addr, dirty);
127 }
128 }
129
130 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
131 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
132 bool in_heap = (decorators & IN_HEAP) != 0;
133
134 bool is_array = (decorators & IS_ARRAY) != 0;
135 bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
136 bool precise = is_array || on_anonymous;
137
138 bool needs_post_barrier = val != noreg && in_heap;
139
140 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, noreg, noreg, noreg);
141 if (needs_post_barrier) {
142 // flatten object address if needed
143 if (!precise || (dst.index() == noreg && dst.disp() == 0)) {
144 store_check(masm, dst.base(), dst);
145 } else {
146 __ lea(tmp1, dst);
147 store_check(masm, tmp1, dst);
148 }
149 }
150 }