1 /*
2 * Copyright (c) 1999, 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 "opto/locknode.hpp"
27 #include "opto/parse.hpp"
28 #include "opto/rootnode.hpp"
29 #include "opto/runtime.hpp"
30
31 //=============================================================================
32 const RegMask &BoxLockNode::in_RegMask(uint i) const {
33 return _inmask;
34 }
35
36 const RegMask &BoxLockNode::out_RegMask() const {
37 return *Matcher::idealreg2regmask[Op_RegP];
38 }
39
40 uint BoxLockNode::size_of() const { return sizeof(*this); }
41
42 BoxLockNode::BoxLockNode( int slot ) : Node( Compile::current()->root() ),
43 _slot(slot), _is_eliminated(false) {
44 init_class_id(Class_BoxLock);
45 init_flags(Flag_rematerialize);
46 OptoReg::Name reg = OptoReg::stack2reg(_slot);
47 if (!RegMask::can_represent(reg, Compile::current()->sync_stack_slots())) {
48 Compile::current()->record_method_not_compilable("must be able to represent all monitor slots in reg mask");
49 return;
50 }
51 _inmask.Insert(reg);
52 }
53
54 //-----------------------------hash--------------------------------------------
55 uint BoxLockNode::hash() const {
56 if (EliminateNestedLocks)
57 return NO_HASH; // Each locked region has own BoxLock node
58 return Node::hash() + _slot + (_is_eliminated ? Compile::current()->fixed_slots() : 0);
59 }
60
61 //------------------------------cmp--------------------------------------------
62 bool BoxLockNode::cmp( const Node &n ) const {
63 if (EliminateNestedLocks)
64 return (&n == this); // Always fail except on self
65 const BoxLockNode &bn = (const BoxLockNode &)n;
66 return bn._slot == _slot && bn._is_eliminated == _is_eliminated;
67 }
68
69 BoxLockNode* BoxLockNode::box_node(Node* box) {
70 // Chase down the BoxNode after RA which may spill box nodes.
71 while (!box->is_BoxLock()) {
72 // if (box_node->is_SpillCopy()) {
73 // Node *m = box_node->in(1);
74 // if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_StoreP) {
75 // box_node = m->in(m->as_Mach()->operand_index(2));
76 // continue;
77 // }
78 // }
79 assert(box->is_SpillCopy() || box->is_Phi(), "Bad spill of Lock.");
80 // Only BoxLock nodes with the same stack slot are merged.
81 // So it is enough to trace one path to find the slot value.
82 box = box->in(1);
83 }
84 return box->as_BoxLock();
85 }
86
87 OptoReg::Name BoxLockNode::reg(Node* box) {
88 return box_node(box)->in_RegMask(0).find_first_elem();
89 }
90
91 // Is BoxLock node used for one simple lock region (same box and obj)?
92 bool BoxLockNode::is_simple_lock_region(LockNode** unique_lock, Node* obj, Node** bad_lock) {
93 LockNode* lock = nullptr;
94 bool has_one_lock = false;
95 for (uint i = 0; i < this->outcnt(); i++) {
96 Node* n = this->raw_out(i);
97 assert(!n->is_Phi(), "should not merge BoxLock nodes");
98 if (n->is_AbstractLock()) {
99 AbstractLockNode* alock = n->as_AbstractLock();
100 // Check lock's box since box could be referenced by Lock's debug info.
101 if (alock->box_node() == this) {
102 if (alock->obj_node()->eqv_uncast(obj)) {
103 if ((unique_lock != nullptr) && alock->is_Lock()) {
104 if (lock == nullptr) {
105 lock = alock->as_Lock();
106 has_one_lock = true;
107 } else if (lock != alock->as_Lock()) {
108 has_one_lock = false;
109 if (bad_lock != nullptr) {
110 *bad_lock = alock;
111 }
112 }
113 }
114 } else {
115 if (bad_lock != nullptr) {
116 *bad_lock = alock;
117 }
118 return false; // Different objects
119 }
120 }
121 }
122 }
123 #ifdef ASSERT
124 // Verify that FastLock and Safepoint reference only this lock region.
125 for (uint i = 0; i < this->outcnt(); i++) {
126 Node* n = this->raw_out(i);
127 if (n->is_FastLock()) {
128 FastLockNode* flock = n->as_FastLock();
129 assert((flock->box_node() == this) && flock->obj_node()->eqv_uncast(obj),"");
130 }
131 // Don't check monitor info in safepoints since the referenced object could
132 // be different from the locked object. It could be Phi node of different
133 // cast nodes which point to this locked object.
134 // We assume that no other objects could be referenced in monitor info
135 // associated with this BoxLock node because all associated locks and
136 // unlocks are reference only this one object.
137 }
138 #endif
139 if (unique_lock != nullptr && has_one_lock) {
140 *unique_lock = lock;
141 }
142 return true;
143 }
144
145 //=============================================================================
146 //-----------------------------hash--------------------------------------------
147 uint FastLockNode::hash() const { return NO_HASH; }
148
149 uint FastLockNode::size_of() const { return sizeof(*this); }
150
151 //------------------------------cmp--------------------------------------------
152 bool FastLockNode::cmp( const Node &n ) const {
153 return (&n == this); // Always fail except on self
154 }
155
156 const Type* FastLockNode::Value(PhaseGVN* phase) const {
157 const Type* in1_t = phase->type(in(1));
158 if (in1_t == Type::TOP) {
159 return Type::TOP;
160 }
161 if (in1_t->is_inlinetypeptr()) {
162 // Locking on inline types always fails
163 return TypeInt::CC_GT;
164 }
165 return TypeInt::CC;
166 }
167
168 //=============================================================================
169 //-----------------------------hash--------------------------------------------
170 uint FastUnlockNode::hash() const { return NO_HASH; }
171
172 //------------------------------cmp--------------------------------------------
173 bool FastUnlockNode::cmp( const Node &n ) const {
174 return (&n == this); // Always fail except on self
175 }
176
177 void FastLockNode::create_rtm_lock_counter(JVMState* state) {
178 #if INCLUDE_RTM_OPT
179 Compile* C = Compile::current();
180 if (C->profile_rtm() || (PrintPreciseRTMLockingStatistics && C->use_rtm())) {
181 RTMLockingNamedCounter* rlnc = (RTMLockingNamedCounter*)
182 OptoRuntime::new_named_counter(state, NamedCounter::RTMLockingCounter);
183 _rtm_counters = rlnc->counters();
184 if (UseRTMForStackLocks) {
185 rlnc = (RTMLockingNamedCounter*)
186 OptoRuntime::new_named_counter(state, NamedCounter::RTMLockingCounter);
187 _stack_rtm_counters = rlnc->counters();
188 }
189 }
190 #endif
191 }
192
193 //=============================================================================
194 //------------------------------do_monitor_enter-------------------------------
195 void Parse::do_monitor_enter() {
196 kill_dead_locals();
197
198 // Null check; get casted pointer.
199 Node* obj = null_check(peek());
200 // Check for locking null object
201 if (stopped()) return;
202
203 {
204 // Synchronizing on an inline type is not allowed
205 BuildCutout unless(this, inline_type_test(obj, /* is_inline = */ false), PROB_MAX);
206 uncommon_trap_exact(Deoptimization::Reason_class_check, Deoptimization::Action_none);
207 }
208
209 // the monitor object is not part of debug info expression stack
210 pop();
211
212 // Insert a FastLockNode which takes as arguments the current thread pointer,
213 // the obj pointer & the address of the stack slot pair used for the lock.
214 shared_lock(obj);
215 }
216
217 //------------------------------do_monitor_exit--------------------------------
218 void Parse::do_monitor_exit() {
219 kill_dead_locals();
220
221 pop(); // Pop oop to unlock
222 // Because monitors are guaranteed paired (else we bail out), we know
223 // the matching Lock for this Unlock. Hence we know there is no need
224 // for a null check on Unlock.
225 shared_unlock(map()->peek_monitor_box(), map()->peek_monitor_obj());
226 }