1 /*
 2  * Copyright (c) 2019, 2022, Red Hat, Inc. 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 
27 #include "gc/shenandoah/shenandoahBarrierSetNMethod.hpp"
28 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
29 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahLock.hpp"
32 #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
33 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
34 #include "memory/iterator.hpp"
35 #include "memory/resourceArea.hpp"
36 #include "runtime/threadWXSetters.inline.hpp"
37 
38 bool ShenandoahBarrierSetNMethod::nmethod_entry_barrier(nmethod* nm) {
39   ShenandoahReentrantLock* lock = ShenandoahNMethod::lock_for_nmethod(nm);
40   assert(lock != nullptr, "Must be");
41   ShenandoahReentrantLocker locker(lock);
42 
43   if (!is_armed(nm)) {
44     // Some other thread got here first and healed the oops
45     // and disarmed the nmethod.
46     return true;
47   }
48 
49   MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
50 
51   if (nm->is_unloading()) {
52     // We don't need to take the lock when unlinking nmethods from
53     // the Method, because it is only concurrently unlinked by
54     // the entry barrier, which acquires the per nmethod lock.
55     nm->unlink_from_method();
56 
57     // We can end up calling nmethods that are unloading
58     // since we clear compiled ICs lazily. Returning false
59     // will re-resolve the call and update the compiled IC.
60     return false;
61   }
62 
63   // Heal oops
64   ShenandoahNMethod::heal_nmethod(nm);
65 
66   // CodeCache unloading support
67   nm->mark_as_maybe_on_stack();
68 
69   // Disarm
70   ShenandoahNMethod::disarm_nmethod(nm);
71   return true;
72 }