1 /*
 2  * Copyright (c) 2018, 2026, 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
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24 
25 #ifndef SHARE_GC_SHARED_BARRIERSETNMETHOD_HPP
26 #define SHARE_GC_SHARED_BARRIERSETNMETHOD_HPP
27 
28 #include "memory/allocation.hpp"
29 #include "oops/oopsHierarchy.hpp"
30 #include "utilities/formatBuffer.hpp"
31 #include "utilities/globalDefinitions.hpp"
32 #include "utilities/sizes.hpp"
33 
34 class nmethod;
35 
36 class BarrierSetNMethod: public CHeapObj<mtGC> {
37 private:
38   int _current_phase;
39 
40   void deoptimize(nmethod* nm, address* return_addr_ptr);
41 
42 protected:
43   enum {
44     not_entrant = 1 << 31, // armed sticky bit, see make_not_entrant
45     armed = 0,
46     initial = 1,
47   };
48 
49   int guard_value(nmethod* nm);
50   void set_guard_value(nmethod* nm, int value, int bit_mask = ~not_entrant);
51 
52 public:
53   BarrierSetNMethod() : _current_phase(initial) {}
54   bool supports_entry_barrier(nmethod* nm);
55 
56   virtual bool nmethod_entry_barrier(nmethod* nm);
57   virtual ByteSize thread_disarmed_guard_value_offset() const;
58   virtual int* disarmed_guard_value_address() const;
59 
60   int disarmed_guard_value() const;
61 
62   static int nmethod_stub_entry_barrier(address* return_address_ptr);
63   bool nmethod_osr_entry_barrier(nmethod* nm);
64   bool is_armed(nmethod* nm);
65   void arm(nmethod* nm) { guard_with(nm, armed); }
66   void disarm(nmethod* nm);
67   void make_not_entrant(nmethod* nm);
68   bool is_not_entrant(nmethod* nm);
69 
70   void guard_with(nmethod* nm, int value);
71 
72   virtual void arm_all_nmethods();
73 
74   virtual oop oop_load_no_keepalive(const nmethod* nm, int index);
75   virtual oop oop_load_phantom(const nmethod* nm, int index);
76 };
77 
78 
79 #endif // SHARE_GC_SHARED_BARRIERSETNMETHOD_HPP