1 /*
2 * Copyright (c) 2018, 2024, 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 "c1/c1_LIRGenerator.hpp"
27 #include "c1/c1_CodeStubs.hpp"
28 #include "gc/g1/c1/g1BarrierSetC1.hpp"
29 #include "gc/g1/g1BarrierSet.hpp"
30 #include "gc/g1/g1BarrierSetAssembler.hpp"
31 #include "gc/g1/g1HeapRegion.hpp"
32 #include "gc/g1/g1ThreadLocalData.hpp"
33 #include "utilities/macros.hpp"
34
35 #ifdef ASSERT
36 #define __ gen->lir(__FILE__, __LINE__)->
37 #else
38 #define __ gen->lir()->
39 #endif
40
41 void G1PreBarrierStub::emit_code(LIR_Assembler* ce) {
42 G1BarrierSetAssembler* bs = (G1BarrierSetAssembler*)BarrierSet::barrier_set()->barrier_set_assembler();
43 bs->gen_pre_barrier_stub(ce, this);
44 }
45
46 void G1PostBarrierStub::emit_code(LIR_Assembler* ce) {
47 G1BarrierSetAssembler* bs = (G1BarrierSetAssembler*)BarrierSet::barrier_set()->barrier_set_assembler();
48 bs->gen_post_barrier_stub(ce, this);
49 }
50
51 void G1BarrierSetC1::pre_barrier(LIRAccess& access, LIR_Opr addr_opr,
52 LIR_Opr pre_val, CodeEmitInfo* info) {
53 LIRGenerator* gen = access.gen();
54 DecoratorSet decorators = access.decorators();
55
56 // First we test whether marking is in progress.
57 BasicType flag_type;
58 bool patch = (decorators & C1_NEEDS_PATCHING) != 0;
59 bool do_load = pre_val == LIR_OprFact::illegalOpr;
60 if (in_bytes(SATBMarkQueue::byte_width_of_active()) == 4) {
61 flag_type = T_INT;
62 } else {
63 guarantee(in_bytes(SATBMarkQueue::byte_width_of_active()) == 1,
64 "Assumption");
65 // Use unsigned type T_BOOLEAN here rather than signed T_BYTE since some platforms, eg. ARM,
66 // need to use unsigned instructions to use the large offset to load the satb_mark_queue.
67 flag_type = T_BOOLEAN;
68 }
69 LIR_Opr thrd = gen->getThreadPointer();
70 LIR_Address* mark_active_flag_addr =
71 new LIR_Address(thrd,
72 in_bytes(G1ThreadLocalData::satb_mark_queue_active_offset()),
73 flag_type);
74 // Read the marking-in-progress flag.
75 // Note: When loading pre_val requires patching, i.e. do_load == true &&
76 // patch == true, a safepoint can occur while patching. This makes the
77 // pre-barrier non-atomic and invalidates the marking-in-progress check.
78 // Therefore, in the presence of patching, we must repeat the same
79 // marking-in-progress checking before calling into the Runtime. For
80 // simplicity, we do this check unconditionally (regardless of the presence
81 // of patching) in the runtime stub
82 // (G1BarrierSetAssembler::generate_c1_pre_barrier_runtime_stub).
83 LIR_Opr flag_val = gen->new_register(T_INT);
84 __ load(mark_active_flag_addr, flag_val);
85 __ cmp(lir_cond_notEqual, flag_val, LIR_OprFact::intConst(0));
86
87 LIR_PatchCode pre_val_patch_code = lir_patch_none;
88
89 CodeStub* slow;
90
91 if (do_load) {
92 assert(pre_val == LIR_OprFact::illegalOpr, "sanity");
93 assert(addr_opr != LIR_OprFact::illegalOpr, "sanity");
94
95 if (patch)
96 pre_val_patch_code = lir_patch_normal;
97
98 pre_val = gen->new_register(T_OBJECT);
99
100 if (!addr_opr->is_address()) {
101 assert(addr_opr->is_register(), "must be");
102 addr_opr = LIR_OprFact::address(new LIR_Address(addr_opr, T_OBJECT));
103 }
104 slow = new G1PreBarrierStub(addr_opr, pre_val, pre_val_patch_code, info);
105 } else {
106 assert(addr_opr == LIR_OprFact::illegalOpr, "sanity");
107 assert(pre_val->is_register(), "must be");
108 assert(pre_val->type() == T_OBJECT, "must be an object");
109 assert(info == nullptr, "sanity");
110
111 slow = new G1PreBarrierStub(pre_val);
112 }
113
114 __ branch(lir_cond_notEqual, slow);
115 __ branch_destination(slow->continuation());
116 }
117
118 void G1BarrierSetC1::post_barrier(LIRAccess& access, LIR_Opr addr, LIR_Opr new_val) {
119 LIRGenerator* gen = access.gen();
120 DecoratorSet decorators = access.decorators();
121 bool in_heap = (decorators & IN_HEAP) != 0;
122 if (!in_heap) {
123 return;
124 }
125
126 // If the "new_val" is a constant null, no barrier is necessary.
127 if (new_val->is_constant() &&
128 new_val->as_constant_ptr()->as_jobject() == nullptr) return;
129
130 if (!new_val->is_register()) {
131 LIR_Opr new_val_reg = gen->new_register(T_OBJECT);
132 if (new_val->is_constant()) {
133 __ move(new_val, new_val_reg);
134 } else {
135 __ leal(new_val, new_val_reg);
136 }
137 new_val = new_val_reg;
138 }
139 assert(new_val->is_register(), "must be a register at this point");
140
141 if (addr->is_address()) {
142 LIR_Address* address = addr->as_address_ptr();
143 LIR_Opr ptr = gen->new_pointer_register();
144 if (!address->index()->is_valid() && address->disp() == 0) {
145 __ move(address->base(), ptr);
146 } else {
147 assert(address->disp() != max_jint, "lea doesn't support patched addresses!");
148 __ leal(addr, ptr);
149 }
150 addr = ptr;
151 }
152 assert(addr->is_register(), "must be a register at this point");
153
154 LIR_Opr xor_res = gen->new_pointer_register();
155 LIR_Opr xor_shift_res = gen->new_pointer_register();
156 if (two_operand_lir_form) {
157 __ move(addr, xor_res);
158 __ logical_xor(xor_res, new_val, xor_res);
159 __ move(xor_res, xor_shift_res);
160 __ unsigned_shift_right(xor_shift_res,
161 LIR_OprFact::intConst(checked_cast<jint>(G1HeapRegion::LogOfHRGrainBytes)),
162 xor_shift_res,
163 LIR_Opr::illegalOpr());
164 } else {
165 __ logical_xor(addr, new_val, xor_res);
166 __ unsigned_shift_right(xor_res,
167 LIR_OprFact::intConst(checked_cast<jint>(G1HeapRegion::LogOfHRGrainBytes)),
168 xor_shift_res,
169 LIR_Opr::illegalOpr());
170 }
171
172 __ cmp(lir_cond_notEqual, xor_shift_res, LIR_OprFact::intptrConst(NULL_WORD));
173
174 CodeStub* slow = new G1PostBarrierStub(addr, new_val);
175 __ branch(lir_cond_notEqual, slow);
176 __ branch_destination(slow->continuation());
177 }
178
179 void G1BarrierSetC1::load_at_resolved(LIRAccess& access, LIR_Opr result) {
180 DecoratorSet decorators = access.decorators();
181 bool is_weak = (decorators & ON_WEAK_OOP_REF) != 0;
182 bool is_phantom = (decorators & ON_PHANTOM_OOP_REF) != 0;
183 bool is_anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
184 LIRGenerator *gen = access.gen();
185
186 BarrierSetC1::load_at_resolved(access, result);
187
188 if (access.is_oop() && (is_weak || is_phantom || is_anonymous)) {
189 // Register the value in the referent field with the pre-barrier
190 LabelObj *Lcont_anonymous;
191 if (is_anonymous) {
192 Lcont_anonymous = new LabelObj();
193 generate_referent_check(access, Lcont_anonymous);
194 }
195 pre_barrier(access, LIR_OprFact::illegalOpr /* addr_opr */,
196 result /* pre_val */, access.patch_emit_info() /* info */);
197 if (is_anonymous) {
198 __ branch_destination(Lcont_anonymous->label());
199 }
200 }
201 }
202
203 class C1G1PreBarrierCodeGenClosure : public StubAssemblerCodeGenClosure {
204 virtual OopMapSet* generate_code(StubAssembler* sasm) {
205 G1BarrierSetAssembler* bs = (G1BarrierSetAssembler*)BarrierSet::barrier_set()->barrier_set_assembler();
206 bs->generate_c1_pre_barrier_runtime_stub(sasm);
207 return nullptr;
208 }
209 };
210
211 class C1G1PostBarrierCodeGenClosure : public StubAssemblerCodeGenClosure {
212 virtual OopMapSet* generate_code(StubAssembler* sasm) {
213 G1BarrierSetAssembler* bs = (G1BarrierSetAssembler*)BarrierSet::barrier_set()->barrier_set_assembler();
214 bs->generate_c1_post_barrier_runtime_stub(sasm);
215 return nullptr;
216 }
217 };
218
219 void G1BarrierSetC1::generate_c1_runtime_stubs(BufferBlob* buffer_blob) {
220 C1G1PreBarrierCodeGenClosure pre_code_gen_cl;
221 C1G1PostBarrierCodeGenClosure post_code_gen_cl;
222 _pre_barrier_c1_runtime_code_blob = Runtime1::generate_blob(buffer_blob, C1StubId::NO_STUBID, "g1_pre_barrier_slow",
223 false, &pre_code_gen_cl);
224 _post_barrier_c1_runtime_code_blob = Runtime1::generate_blob(buffer_blob, C1StubId::NO_STUBID, "g1_post_barrier_slow",
225 false, &post_code_gen_cl);
226 }