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 
 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 disp = (intptr_t) ct->byte_map_base();
 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 #ifdef _LP64
 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   __ mov64(tmp, disp);
 68   __ addptr(addr, tmp);
 69 __ BIND(L_loop);
 70   __ movb(Address(addr, count, Address::times_1), 0);
 71   __ decrement(count);
 72   __ jcc(Assembler::greaterEqual, L_loop);
 73 #else
 74   __ lea(end,  Address(addr, count, Address::times_ptr, -wordSize));
 75   __ shrptr(addr, CardTable::card_shift);
 76   __ shrptr(end,   CardTable::card_shift);
 77   __ subptr(end, addr); // end --> count
 78 __ BIND(L_loop);
 79   Address cardtable(addr, count, Address::times_1, disp);
 80   __ movb(cardtable, 0);
 81   __ decrement(count);
 82   __ jcc(Assembler::greaterEqual, L_loop);
 83 #endif
 84 
 85 __ BIND(L_done);
 86 }
 87 
 88 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst) {
 89   // Does a store check for the oop in register obj. The content of
 90   // register obj is destroyed afterwards.
 91   BarrierSet* bs = BarrierSet::barrier_set();
 92 
 93   CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs);
 94   CardTable* ct = ctbs->card_table();
 95 
 96   __ shrptr(obj, CardTable::card_shift);
 97 
 98   Address card_addr;
 99 
100   // The calculation for byte_map_base is as follows:
101   // byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
102   // So this essentially converts an address to a displacement and it will
103   // never need to be relocated. On 64bit however the value may be too
104   // large for a 32bit displacement.
105   intptr_t byte_map_base = (intptr_t)ct->byte_map_base();
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));
116   }
117 
118   int dirty = CardTable::dirty_card_val();
119   if (UseCondCardMark) {
120     Label L_already_dirty;
121     __ cmpb(card_addr, dirty);
122     __ jcc(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       if (tmp3 != noreg) {
145         // Called by MacroAssembler::pack_inline_helper. We cannot corrupt the dst.base() register
146         __ movptr(tmp3, dst.base());
147         store_check(masm, tmp3, dst);
148       } else {
149         // It's OK to corrupt the dst.base() register.
150         store_check(masm, dst.base(), dst);
151       }
152     } else {
153       __ lea(tmp1, dst);
154       store_check(masm, tmp1, dst);
155     }
156   }
157 }