1 /*
2 * Copyright (c) 2018, 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 "opto/arraycopynode.hpp"
27 #include "opto/graphKit.hpp"
28 #include "opto/idealKit.hpp"
29 #include "opto/narrowptrnode.hpp"
30 #include "gc/shared/c2/modRefBarrierSetC2.hpp"
31 #include "utilities/macros.hpp"
32
33 Node* ModRefBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
34 DecoratorSet decorators = access.decorators();
35 GraphKit* kit = access.kit();
36
37 const TypePtr* adr_type = access.addr().type();
38 Node* adr = access.addr().node();
39
40 bool on_array = (decorators & IN_HEAP_ARRAY) != 0;
41 bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
42 bool on_heap = (decorators & IN_HEAP) != 0;
43 bool use_precise = on_array || anonymous;
44
45 if (!access.is_oop() || (!on_heap && !anonymous)) {
46 return BarrierSetC2::store_at_resolved(access, val);
47 }
48
49 uint adr_idx = kit->C->get_alias_index(adr_type);
50 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
51
52 pre_barrier(kit, true /* do_load */, kit->control(), access.base(), adr, adr_idx, val.node(),
53 static_cast<const TypeOopPtr*>(val.type()), NULL /* pre_val */, access.type());
54 Node* store = BarrierSetC2::store_at_resolved(access, val);
55 post_barrier(kit, kit->control(), access.raw_access(), access.base(), adr, adr_idx, val.node(),
56 access.type(), use_precise);
57
58 return store;
59 }
60
61 Node* ModRefBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val,
62 Node* new_val, const Type* value_type) const {
63 GraphKit* kit = access.kit();
64
65 if (!access.is_oop()) {
66 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
67 }
68
69 pre_barrier(kit, false /* do_load */,
70 kit->control(), NULL, NULL, max_juint, NULL, NULL,
71 expected_val /* pre_val */, T_OBJECT);
72
73 Node* result = BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
74
75 post_barrier(kit, kit->control(), access.raw_access(), access.base(),
76 access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
77
78 return result;
79 }
80
81 Node* ModRefBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val,
82 Node* new_val, const Type* value_type) const {
83 GraphKit* kit = access.kit();
84
85 if (!access.is_oop()) {
86 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
87 }
88
89 pre_barrier(kit, false /* do_load */,
90 kit->control(), NULL, NULL, max_juint, NULL, NULL,
91 expected_val /* pre_val */, T_OBJECT);
92
93 Node* load_store = BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
94
95 // Emit the post barrier only when the actual store happened. This makes sense
96 // to check only for LS_cmp_* that can fail to set the value.
97 // LS_cmp_exchange does not produce any branches by default, so there is no
98 // boolean result to piggyback on. TODO: When we merge CompareAndSwap with
99 // CompareAndExchange and move branches here, it would make sense to conditionalize
100 // post_barriers for LS_cmp_exchange as well.
101 //
102 // CAS success path is marked more likely since we anticipate this is a performance
103 // critical path, while CAS failure path can use the penalty for going through unlikely
104 // path as backoff. Which is still better than doing a store barrier there.
105 IdealKit ideal(kit);
106 ideal.if_then(load_store, BoolTest::ne, ideal.ConI(0), PROB_STATIC_FREQUENT); {
107 kit->sync_kit(ideal);
108 post_barrier(kit, ideal.ctrl(), access.raw_access(), access.base(),
109 access.addr().node(), access.alias_idx(), new_val, T_OBJECT, true);
110 ideal.sync_kit(kit);
111 } ideal.end_if();
112 kit->final_sync(ideal);
113
114 return load_store;
115 }
116
117 Node* ModRefBarrierSetC2::atomic_xchg_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* value_type) const {
118 GraphKit* kit = access.kit();
119
120 Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, new_val, value_type);
121 if (!access.is_oop()) {
122 return result;
123 }
124
125 // Don't need to load pre_val. The old value is returned by load_store.
126 // The pre_barrier can execute after the xchg as long as no safepoint
127 // gets inserted between them.
128 pre_barrier(kit, false /* do_load */,
129 kit->control(), NULL, NULL, max_juint, NULL, NULL,
130 result /* pre_val */, T_OBJECT);
131 post_barrier(kit, kit->control(), access.raw_access(), access.base(), access.addr().node(),
132 access.alias_idx(), new_val, T_OBJECT, true);
133
134 return result;
135 }