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, Register tmp3) {
 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, noreg);
 89   if (needs_post_barrier) {
 90     // flatten object address if needed
 91     if (!precise || (dst.index() == noreg && dst.offset() == 0)) {
 92       if (tmp3 != noreg) {
 93         // Called by MacroAssembler::pack_inline_helper. We cannot corrupt the dst.base() register
 94         __ mov(tmp3, dst.base());
 95         store_check(masm, tmp3, dst);
 96       } else {
 97         // It's OK to corrupt the dst.base() register.
 98         store_check(masm, dst.base(), dst);
 99       }
100 
101     } else {
102       __ lea(r3, dst);
103       store_check(masm, r3, dst);
104     }
105   }
106 
107 }