1 /*
2 * Copyright (c) 2018, 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 "precompiled.hpp"
26 #include "asm/macroAssembler.inline.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/collectedHeap.hpp"
32 #include "runtime/globals.hpp"
33
34 #define __ masm->
35
36 #ifdef PRODUCT
37 #define BLOCK_COMMENT(str) /* nothing */
38 #else
39 #define BLOCK_COMMENT(str) __ block_comment(str)
40 #endif
41
42 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
43
gen_write_ref_array_post_barrier(MacroAssembler * masm,DecoratorSet decorators,Register addr,Register count,Register tmp)44 void CardTableBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
45 Register addr, Register count, Register tmp) {
46 BLOCK_COMMENT("CardTablePostBarrier");
47 BarrierSet* bs = BarrierSet::barrier_set();
48 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
49 CardTable* ct = ctbs->card_table();
50 assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "adjust this code");
51
52 Label L_cardtable_loop, L_done;
53
54 __ cbz_32(count, L_done); // zero count - nothing to do
55
56 __ add_ptr_scaled_int32(count, addr, count, LogBytesPerHeapOop);
57 __ sub(count, count, BytesPerHeapOop); // last addr
58
59 __ logical_shift_right(addr, addr, CardTable::card_shift);
60 __ logical_shift_right(count, count, CardTable::card_shift);
61 __ sub(count, count, addr); // nb of cards
62
63 // warning: Rthread has not been preserved
64 __ mov_address(tmp, (address) ct->byte_map_base(), symbolic_Relocation::card_table_reference);
65 __ add(addr,tmp, addr);
66
67 Register zero = __ zero_register(tmp);
68
69 __ BIND(L_cardtable_loop);
70 __ strb(zero, Address(addr, 1, post_indexed));
71 __ subs(count, count, 1);
72 __ b(L_cardtable_loop, ge);
73 __ BIND(L_done);
74 }
75
oop_store_at(MacroAssembler * masm,DecoratorSet decorators,BasicType type,Address obj,Register new_val,Register tmp1,Register tmp2,Register tmp3,bool is_null)76 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
77 Address obj, Register new_val, Register tmp1, Register tmp2, Register tmp3, bool is_null) {
78 bool is_array = (decorators & IS_ARRAY) != 0;
79 bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
80 bool precise = is_array || on_anonymous;
81
82 if (is_null) {
83 BarrierSetAssembler::store_at(masm, decorators, type, obj, new_val, tmp1, tmp2, tmp3, true);
84 } else {
85 assert (!precise || (obj.index() == noreg && obj.disp() == 0),
86 "store check address should be calculated beforehand");
87
88 store_check_part1(masm, tmp1);
89 BarrierSetAssembler::store_at(masm, decorators, type, obj, new_val, tmp1, tmp2, tmp3, false);
90 new_val = noreg;
91 store_check_part2(masm, obj.base(), tmp1, tmp2);
92 }
93 }
94
95 // The 1st part of the store check.
96 // Sets card_table_base register.
store_check_part1(MacroAssembler * masm,Register card_table_base)97 void CardTableBarrierSetAssembler::store_check_part1(MacroAssembler* masm, Register card_table_base) {
98 // Check barrier set type (should be card table) and element size
99 BarrierSet* bs = BarrierSet::barrier_set();
100 assert(bs->kind() == BarrierSet::CardTableBarrierSet,
101 "Wrong barrier set kind");
102
103 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
104 CardTable* ct = ctbs->card_table();
105 assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "Adjust store check code");
106
107 // Load card table base address.
108
109 /* Performance note.
110
111 There is an alternative way of loading card table base address
112 from thread descriptor, which may look more efficient:
113
114 ldr(card_table_base, Address(Rthread, JavaThread::card_table_base_offset()));
115
116 However, performance measurements of micro benchmarks and specJVM98
117 showed that loading of card table base from thread descriptor is
118 7-18% slower compared to loading of literal embedded into the code.
119 Possible cause is a cache miss (card table base address resides in a
120 rarely accessed area of thread descriptor).
121 */
122 // TODO-AARCH64 Investigate if mov_slow is faster than ldr from Rthread on AArch64
123 __ mov_address(card_table_base, (address)ct->byte_map_base(), symbolic_Relocation::card_table_reference);
124 }
125
126 // The 2nd part of the store check.
store_check_part2(MacroAssembler * masm,Register obj,Register card_table_base,Register tmp)127 void CardTableBarrierSetAssembler::store_check_part2(MacroAssembler* masm, Register obj, Register card_table_base, Register tmp) {
128 assert_different_registers(obj, card_table_base, tmp);
129
130 BarrierSet* bs = BarrierSet::barrier_set();
131 assert(bs->kind() == BarrierSet::CardTableBarrierSet,
132 "Wrong barrier set kind");
133
134 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
135 CardTable* ct = ctbs->card_table();
136 assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "Adjust store check code");
137
138 assert(CardTable::dirty_card_val() == 0, "Dirty card value must be 0 due to optimizations.");
139 #ifdef AARCH64
140 add(card_table_base, card_table_base, AsmOperand(obj, lsr, CardTable::card_shift));
141 Address card_table_addr(card_table_base);
142 #else
143 Address card_table_addr(card_table_base, obj, lsr, CardTable::card_shift);
144 #endif
145
146 if (UseCondCardMark) {
147 if (ct->scanned_concurrently()) {
148 __ membar(MacroAssembler::Membar_mask_bits(MacroAssembler::StoreLoad), noreg);
149 }
150 Label already_dirty;
151
152 __ ldrb(tmp, card_table_addr);
153 __ cbz(tmp, already_dirty);
154
155 set_card(masm, card_table_base, card_table_addr, tmp);
156 __ bind(already_dirty);
157
158 } else {
159 if (ct->scanned_concurrently()) {
160 __ membar(MacroAssembler::Membar_mask_bits(MacroAssembler::StoreStore), noreg);
161 }
162 set_card(masm, card_table_base, card_table_addr, tmp);
163 }
164 }
165
set_card(MacroAssembler * masm,Register card_table_base,Address card_table_addr,Register tmp)166 void CardTableBarrierSetAssembler::set_card(MacroAssembler* masm, Register card_table_base, Address card_table_addr, Register tmp) {
167 #ifdef AARCH64
168 strb(ZR, card_table_addr);
169 #else
170 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(BarrierSet::barrier_set());
171 CardTable* ct = ctbs->card_table();
172 if ((((uintptr_t)ct->byte_map_base() & 0xff) == 0)) {
173 // Card table is aligned so the lowest byte of the table address base is zero.
174 // This works only if the code is not saved for later use, possibly
175 // in a context where the base would no longer be aligned.
176 __ strb(card_table_base, card_table_addr);
177 } else {
178 __ mov(tmp, 0);
179 __ strb(tmp, card_table_addr);
180 }
181 #endif // AARCH64
182 }
183