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::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
45 Register addr, Register count, Register tmp) {
46 BarrierSet *bs = BarrierSet::barrier_set();
47 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
48 CardTable* ct = ctbs->card_table();
49 intptr_t disp = (intptr_t) ct->byte_map_base();
50 SHENANDOAHGC_ONLY(assert(!UseShenandoahGC, "Shenandoah byte_map_base is not constant.");)
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 __ leaq(end, Address(addr, count, TIMES_OOP, 0)); // end == addr+count*oop_size
61 __ subptr(end, BytesPerHeapOop); // end - 1 to make inclusive
62 __ shrptr(addr, CardTable::card_shift());
63 __ shrptr(end, CardTable::card_shift());
64 __ subptr(end, addr); // end --> cards count
65
66 __ mov64(tmp, disp);
67 __ addptr(addr, tmp);
68 __ BIND(L_loop);
69 __ movb(Address(addr, count, Address::times_1), 0);
70 __ decrement(count);
71 __ jcc(Assembler::greaterEqual, L_loop);
72
73 __ BIND(L_done);
74 }
75
76 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst) {
77 // Does a store check for the oop in register obj. The content of
78 // register obj is destroyed afterwards.
79 BarrierSet* bs = BarrierSet::barrier_set();
80
81 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
82 CardTable* ct = ctbs->card_table();
83
84 __ shrptr(obj, CardTable::card_shift());
85
86 Address card_addr;
87
88 // The calculation for byte_map_base is as follows:
89 // byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
90 // So this essentially converts an address to a displacement and it will
91 // never need to be relocated. On 64bit however the value may be too
92 // large for a 32bit displacement.
93 intptr_t byte_map_base = (intptr_t)ct->byte_map_base();
94 if (__ is_simm32(byte_map_base)) {
95 card_addr = Address(noreg, obj, Address::times_1, byte_map_base);
96 } else {
97 // By doing it as an ExternalAddress 'byte_map_base' could be converted to a rip-relative
98 // displacement and done in a single instruction given favorable mapping and a
99 // smarter version of as_Address. However, 'ExternalAddress' generates a relocation
100 // entry and that entry is not properly handled by the relocation code.
101 AddressLiteral cardtable((address)byte_map_base, relocInfo::none);
102 Address index(noreg, obj, Address::times_1);
103 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch1);
104 }
105
106 int dirty = CardTable::dirty_card_val();
107 if (UseCondCardMark) {
108 Label L_already_dirty;
109 __ cmpb(card_addr, dirty);
110 __ jccb(Assembler::equal, L_already_dirty);
111 __ movb(card_addr, dirty);
112 __ bind(L_already_dirty);
113 } else {
114 __ movb(card_addr, dirty);
115 }
116 }
117
118 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
119 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) {
120 bool in_heap = (decorators & IN_HEAP) != 0;
121
122 bool is_array = (decorators & IS_ARRAY) != 0;
123 bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
124 bool precise = is_array || on_anonymous;
125
126 bool needs_post_barrier = val != noreg && in_heap;
127
128 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, noreg, noreg, noreg);
129 if (needs_post_barrier) {
130 // flatten object address if needed
131 if (!precise || (dst.index() == noreg && dst.disp() == 0)) {
132 store_check(masm, dst.base(), dst);
133 } else {
134 __ lea(tmp1, dst);
135 store_check(masm, tmp1, dst);
136 }
137 }
138 }