1 /*
 2  * Copyright (c) 2018, 2021, 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/gc_globals.hpp"
32 #include "interpreter/interp_masm.hpp"
33 
34 #define __ masm->
35 
36 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst) {
37 
38   BarrierSet* bs = BarrierSet::barrier_set();
39   assert(bs->kind() == BarrierSet::CardTableBarrierSet, "Wrong barrier set kind");
40 
41   __ lsr(obj, obj, CardTable::card_shift);
42 
43   assert(CardTable::dirty_card_val() == 0, "must be");
44 
45   __ load_byte_map_base(rscratch1);
46 
47   if (UseCondCardMark) {
48     Label L_already_dirty;
49     __ ldrb(rscratch2,  Address(obj, rscratch1));
50     __ cbz(rscratch2, L_already_dirty);
51     __ strb(zr, Address(obj, rscratch1));
52     __ bind(L_already_dirty);
53   } else {
54     __ strb(zr, Address(obj, rscratch1));
55   }
56 }
57 
58 void CardTableBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators,
59                                                                     Register start, Register count, Register scratch, RegSet saved_regs) {
60   Label L_loop, L_done;
61   const Register end = count;
62 
63   __ cbz(count, L_done); // zero count - nothing to do
64 
65   __ lea(end, Address(start, count, Address::lsl(LogBytesPerHeapOop))); // end = start + count << LogBytesPerHeapOop
66   __ sub(end, end, BytesPerHeapOop); // last element address to make inclusive
67   __ lsr(start, start, CardTable::card_shift);
68   __ lsr(end, end, CardTable::card_shift);
69   __ sub(count, end, start); // number of bytes to copy
70 
71   __ load_byte_map_base(scratch);
72   __ add(start, start, scratch);
73   __ bind(L_loop);
74   __ strb(zr, Address(start, count));
75   __ subs(count, count, 1);
76   __ br(Assembler::GE, L_loop);
77   __ bind(L_done);
78 }
79 
80 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
81                                                 Address dst, Register val, Register tmp1, Register tmp2) {
82   bool in_heap = (decorators & IN_HEAP) != 0;
83   bool is_array = (decorators & IS_ARRAY) != 0;
84   bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
85   bool precise = is_array || on_anonymous;
86 
87   bool needs_post_barrier = val != noreg && in_heap;
88   BarrierSetAssembler::store_at(masm, decorators, type, dst, val, noreg, noreg);
89   if (needs_post_barrier) {
90     // flatten object address if needed
91     if (!precise || (dst.index() == noreg && dst.offset() == 0)) {
92       store_check(masm, dst.base(), dst);
93     } else {
94       __ lea(r3, dst);
95       store_check(masm, r3, dst);
96     }
97   }
98 }