1 /*
2 * Copyright (c) 1997, 2023, 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 "gc/shared/barrierSet.hpp"
27 #include "gc/shared/barrierSetAssembler.hpp"
28 #include "gc/shared/barrierSetNMethod.hpp"
29 #include "gc/shared/barrierSetStackChunk.hpp"
30 #include "runtime/continuation.hpp"
31 #include "runtime/javaThread.hpp"
32 #include "utilities/debug.hpp"
33 #include "utilities/macros.hpp"
34
35 BarrierSet* BarrierSet::_barrier_set = nullptr;
36
37 void BarrierSet::set_barrier_set(BarrierSet* barrier_set) {
38 assert(_barrier_set == nullptr, "Already initialized");
39 _barrier_set = barrier_set;
40
41 // Notify barrier set of the current (main) thread. Normally the
42 // Thread constructor deals with this, but the main thread is
43 // created before we get here. Verify it isn't yet on the thread
44 // list, else we'd also need to call BarrierSet::on_thread_attach.
45 // This is the only thread that can exist at this point; the Thread
46 // constructor objects to other threads being created before the
47 // barrier set is available.
48 assert(Thread::current()->is_Java_thread(),
49 "Expected main thread to be a JavaThread");
50 assert(!JavaThread::current()->on_thread_list(),
51 "Main thread already on thread list.");
52 _barrier_set->on_thread_create(Thread::current());
53 }
54
55 static BarrierSetNMethod* select_barrier_set_nmethod(BarrierSetNMethod* barrier_set_nmethod) {
56 if (barrier_set_nmethod != nullptr) {
57 // The GC needs nmethod entry barriers to do concurrent GC
58 return barrier_set_nmethod;
59 } else {
60 // The GC needs nmethod entry barriers to deal with continuations
61 // and code cache unloading
62 return new BarrierSetNMethod();
63 }
64 }
65
66 static BarrierSetStackChunk* select_barrier_set_stack_chunk(BarrierSetStackChunk* barrier_set_stack_chunk) {
67 if (barrier_set_stack_chunk != nullptr) {
68 return barrier_set_stack_chunk;
69 } else {
70 return new BarrierSetStackChunk();
71 }
72 }
73
74 BarrierSet::BarrierSet(BarrierSetAssembler* barrier_set_assembler,
75 BarrierSetC1* barrier_set_c1,
76 BarrierSetC2* barrier_set_c2,
77 BarrierSetNMethod* barrier_set_nmethod,
78 BarrierSetStackChunk* barrier_set_stack_chunk,
79 const FakeRtti& fake_rtti) :
80 _fake_rtti(fake_rtti),
81 _barrier_set_assembler(barrier_set_assembler),
82 _barrier_set_c1(barrier_set_c1),
83 _barrier_set_c2(barrier_set_c2),
84 _barrier_set_nmethod(select_barrier_set_nmethod(barrier_set_nmethod)),
85 _barrier_set_stack_chunk(select_barrier_set_stack_chunk(barrier_set_stack_chunk)) {
86 }
87
88 void BarrierSet::on_thread_attach(Thread* thread) {
89 BarrierSetNMethod* bs_nm = barrier_set_nmethod();
90 if (bs_nm != nullptr) {
91 thread->set_nmethod_disarmed_guard_value(bs_nm->disarmed_guard_value());
92 }
93 }
94
95 // Called from init.cpp
96 void gc_barrier_stubs_init() {
97 BarrierSet* bs = BarrierSet::barrier_set();
98 #ifndef ZERO
99 BarrierSetAssembler* bs_assembler = bs->barrier_set_assembler();
100 bs_assembler->barrier_stubs_init();
101 #endif
102 }