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 "code/aotCodeCache.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 byte_map_base = (intptr_t) ct->byte_map_base(); 51 SHENANDOAHGC_ONLY(assert(!UseShenandoahGC, "Shenandoah byte_map_base is not constant.");) 52 53 Label L_loop, L_done; 54 const Register end = count; 55 assert_different_registers(addr, end); 56 57 __ testl(count, count); 58 __ jcc(Assembler::zero, L_done); // zero count - nothing to do 59 60 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 #if INCLUDE_CDS 68 if (AOTCodeCache::is_on_for_dump()) { 69 __ movptr(tmp, ExternalAddress(AOTRuntimeConstants::card_table_address())); 70 } else 71 #endif 72 { 73 __ mov64(tmp, byte_map_base); 74 } 75 __ addptr(addr, tmp); 76 __ BIND(L_loop); 77 __ movb(Address(addr, count, Address::times_1), 0); 78 __ decrement(count); 79 __ jcc(Assembler::greaterEqual, L_loop); 80 81 __ BIND(L_done); 82 } 83 84 void CardTableBarrierSetAssembler::store_check(MacroAssembler* masm, Register obj, Address dst, Register rscratch) { 85 // Does a store check for the oop in register obj. The content of 86 // register obj is destroyed afterwards. 87 BarrierSet* bs = BarrierSet::barrier_set(); 88 89 CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(bs); 90 CardTable* ct = ctbs->card_table(); 91 92 __ shrptr(obj, CardTable::card_shift()); 93 94 Address card_addr; 95 precond(rscratch != noreg); 96 97 // The calculation for byte_map_base is as follows: 98 // byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift); 99 // So this essentially converts an address to a displacement and it will 100 // never need to be relocated. On 64bit however the value may be too 101 // large for a 32bit displacement. 102 intptr_t byte_map_base = (intptr_t)ct->byte_map_base(); 103 #if INCLUDE_CDS 104 if (AOTCodeCache::is_on_for_dump()) { 105 __ movptr(rscratch, ExternalAddress(AOTRuntimeConstants::card_table_address())); 106 card_addr = Address(rscratch, obj, Address::times_1, 0); 107 } else 108 #endif 109 if (__ is_simm32(byte_map_base)) { 110 card_addr = Address(noreg, obj, Address::times_1, byte_map_base); 111 } else { 112 // By doing it as an ExternalAddress 'byte_map_base' could be converted to a rip-relative 113 // displacement and done in a single instruction given favorable mapping and a 114 // smarter version of as_Address. However, 'ExternalAddress' generates a relocation 115 // entry and that entry is not properly handled by the relocation code. 116 AddressLiteral cardtable((address)byte_map_base, relocInfo::none); 117 Address index(noreg, obj, Address::times_1); 118 card_addr = __ as_Address(ArrayAddress(cardtable, index), rscratch); 119 } 120 121 int dirty = CardTable::dirty_card_val(); 122 if (UseCondCardMark) { 123 Label L_already_dirty; 124 __ cmpb(card_addr, dirty); 125 __ jccb(Assembler::equal, L_already_dirty); 126 __ movb(card_addr, dirty); 127 __ bind(L_already_dirty); 128 } else { 129 __ movb(card_addr, dirty); 130 } 131 } 132 133 void CardTableBarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type, 134 Address dst, Register val, Register tmp1, Register tmp2, Register tmp3) { 135 bool in_heap = (decorators & IN_HEAP) != 0; 136 137 bool is_array = (decorators & IS_ARRAY) != 0; 138 bool on_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0; 139 bool precise = is_array || on_anonymous; 140 141 bool needs_post_barrier = val != noreg && in_heap; 142 143 BarrierSetAssembler::store_at(masm, decorators, type, dst, val, noreg, noreg, noreg); 144 if (needs_post_barrier) { 145 // flatten object address if needed 146 if (!precise || (dst.index() == noreg && dst.disp() == 0)) { 147 store_check(masm, dst.base(), dst, tmp2); 148 } else { 149 __ lea(tmp1, dst); 150 store_check(masm, tmp1, dst, tmp2); 151 } 152 } 153 }