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.
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 23  */
 24 
 25 #include "opto/arraycopynode.hpp"
 26 #include "opto/graphKit.hpp"
 27 #include "opto/idealKit.hpp"
 28 #include "gc/shared/c2/modRefBarrierSetC2.hpp"
 29 
 30 Node* ModRefBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
 31   DecoratorSet decorators = access.decorators();
 32 
 33   Node* adr = access.addr().node();
 34 
 35   bool is_array = (decorators & IS_ARRAY) != 0;
 36   bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
 37   bool in_heap = (decorators & IN_HEAP) != 0;
 38   bool use_precise = is_array || anonymous;
 39   bool tightly_coupled_alloc = (decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0;
 40 
 41   const InlineTypeNode* vt = nullptr;
 42   if (access.is_parse_access() && static_cast<C2ParseAccess&>(access).vt() != nullptr) {
 43     vt = static_cast<C2ParseAccess&>(access).vt();
 44   }
 45 
 46   if (vt == nullptr && (!access.is_oop() || tightly_coupled_alloc || (!in_heap && !anonymous))) {
 47     return BarrierSetC2::store_at_resolved(access, val);
 48   }
 49 
 50   assert(access.is_parse_access(), "entry not supported at optimization time");
 51   C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
 52 
 53   Node* store = BarrierSetC2::store_at_resolved(access, val);
 54 
 55   // TODO 8350865
 56   // - We actually only need the post barrier once for non-arrays (same for C1, right)?
 57   // - Value is only needed to determine if we are storing null. Maybe we can go with a simple boolean?
 58   GraphKit* kit = parse_access.kit();
 59   if (vt != nullptr) {
 60     for (uint i = 0; i < vt->field_count(); ++i) {
 61       ciType* type = vt->field_type(i);
 62       if (!type->is_primitive_type()) {
 63         ciInlineKlass* vk = vt->bottom_type()->inline_klass();
 64         int field_offset = vt->field_offset(i) - vk->payload_offset();
 65         Node* value = vt->field_value(i);
 66         Node* field_adr = kit->basic_plus_adr(access.base(), adr, field_offset);
 67         post_barrier(kit, access.base(), field_adr, value, use_precise);
 68       }
 69     }
 70   } else {
 71     post_barrier(kit, access.base(), adr, val.node(), use_precise);
 72   }
 73 
 74   return store;
 75 }
 76 
 77 Node* ModRefBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 78                                                          Node* new_val, const Type* value_type) const {
 79   if (!access.is_oop()) {
 80     return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
 81   }
 82 
 83   Node* result = BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
 84 
 85   post_barrier(access.kit(), access.base(), access.addr().node(), new_val, true);
 86 
 87   return result;
 88 }
 89 
 90 Node* ModRefBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 91                                                           Node* new_val, const Type* value_type) const {
 92   GraphKit* kit = access.kit();
 93 
 94   if (!access.is_oop()) {
 95     return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
 96   }
 97 
 98   Node* load_store = BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
 99 
100   // Emit the post barrier only when the actual store happened. This makes sense
101   // to check only for LS_cmp_* that can fail to set the value.
102   // LS_cmp_exchange does not produce any branches by default, so there is no
103   // boolean result to piggyback on. TODO: When we merge CompareAndSwap with
104   // CompareAndExchange and move branches here, it would make sense to conditionalize
105   // post_barriers for LS_cmp_exchange as well.
106   //
107   // CAS success path is marked more likely since we anticipate this is a performance
108   // critical path, while CAS failure path can use the penalty for going through unlikely
109   // path as backoff. Which is still better than doing a store barrier there.
110   IdealKit ideal(kit);
111   ideal.if_then(load_store, BoolTest::ne, ideal.ConI(0), PROB_STATIC_FREQUENT); {
112     kit->sync_kit(ideal);
113     post_barrier(kit, access.base(), access.addr().node(), new_val, true);
114     ideal.sync_kit(kit);
115   } ideal.end_if();
116   kit->final_sync(ideal);
117 
118   return load_store;
119 }
120 
121 Node* ModRefBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const {
122   Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, new_val, value_type);
123   if (!access.is_oop()) {
124     return result;
125   }
126 
127   post_barrier(access.kit(), access.base(), access.addr().node(), new_val, true);
128 
129   return result;
130 }