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 class patchable_barrier_Relocation;
36 
37 class BarrierSetNMethod: public CHeapObj<mtGC> {
38 private:
39   int _current_phase;
40 
41   void deoptimize(nmethod* nm, address* return_addr_ptr);
42 
43 protected:
44   enum {
45     not_entrant = 1 << 31, // armed sticky bit, see make_not_entrant
46     armed = 0,
47     initial = 1,
48   };
49 
50   int guard_value(nmethod* nm);
51   void set_guard_value(nmethod* nm, int value, int bit_mask = ~not_entrant);
52 
53 public:
54   BarrierSetNMethod() : _current_phase(initial) {}
55   bool supports_entry_barrier(nmethod* nm);
56 
57   virtual bool nmethod_entry_barrier(nmethod* nm);
58   virtual ByteSize thread_disarmed_guard_value_offset() const;
59   virtual int* disarmed_guard_value_address() const;
60 
61   int disarmed_guard_value() const;
62 
63   virtual void patch_barrier_relocation(patchable_barrier_Relocation* reloc) {};
64 
65   static int nmethod_stub_entry_barrier(address* return_address_ptr);
66   bool nmethod_osr_entry_barrier(nmethod* nm);
67   bool is_armed(nmethod* nm);
68   void arm(nmethod* nm) { guard_with(nm, armed); }
69   void disarm(nmethod* nm);
70   void make_not_entrant(nmethod* nm);
71   bool is_not_entrant(nmethod* nm);
72 
73   void guard_with(nmethod* nm, int value);
74 
75   virtual void arm_all_nmethods();
76 
77   virtual oop oop_load_no_keepalive(const nmethod* nm, int index);
78   virtual oop oop_load_phantom(const nmethod* nm, int index);
79 };
80 
81 
82 #endif // SHARE_GC_SHARED_BARRIERSETNMETHOD_HPP