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 // This class is used internally by nmethods, to cache
26 // exception/pc/handler information.
27
28 class ExceptionCache : public CHeapObj {
29 friend class VMStructs;
30 private:
31 static address _unwind_handler;
32 enum { cache_size = 16 };
33 klassOop _exception_type;
34 address _pc[cache_size];
35 address _handler[cache_size];
36 int _count;
37 ExceptionCache* _next;
38
39 address pc_at(int index) { assert(index >= 0 && index < count(),""); return _pc[index]; }
40 void set_pc_at(int index, address a) { assert(index >= 0 && index < cache_size,""); _pc[index] = a; }
41 address handler_at(int index) { assert(index >= 0 && index < count(),""); return _handler[index]; }
42 void set_handler_at(int index, address a) { assert(index >= 0 && index < cache_size,""); _handler[index] = a; }
43 int count() { return _count; }
44 void increment_count() { _count++; }
687 // Locks an nmethod so its code will not get removed, even if it is a zombie/not_entrant method
688 class nmethodLocker : public StackObj {
689 nmethod* _nm;
690
691 static void lock_nmethod(nmethod* nm); // note: nm can be NULL
692 static void unlock_nmethod(nmethod* nm); // (ditto)
693
694 public:
695 nmethodLocker(address pc); // derive nm from pc
696 nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
697 nmethodLocker() { _nm = NULL; }
698 ~nmethodLocker() { unlock_nmethod(_nm); }
699
700 nmethod* code() { return _nm; }
701 void set_code(nmethod* new_nm) {
702 unlock_nmethod(_nm); // note: This works even if _nm==new_nm.
703 _nm = new_nm;
704 lock_nmethod(_nm);
705 }
706 };
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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 #ifndef SHARE_VM_CODE_NMETHOD_HPP
26 #define SHARE_VM_CODE_NMETHOD_HPP
27
28 #include "code/codeBlob.hpp"
29 #include "code/pcDesc.hpp"
30
31 // This class is used internally by nmethods, to cache
32 // exception/pc/handler information.
33
34 class ExceptionCache : public CHeapObj {
35 friend class VMStructs;
36 private:
37 static address _unwind_handler;
38 enum { cache_size = 16 };
39 klassOop _exception_type;
40 address _pc[cache_size];
41 address _handler[cache_size];
42 int _count;
43 ExceptionCache* _next;
44
45 address pc_at(int index) { assert(index >= 0 && index < count(),""); return _pc[index]; }
46 void set_pc_at(int index, address a) { assert(index >= 0 && index < cache_size,""); _pc[index] = a; }
47 address handler_at(int index) { assert(index >= 0 && index < count(),""); return _handler[index]; }
48 void set_handler_at(int index, address a) { assert(index >= 0 && index < cache_size,""); _handler[index] = a; }
49 int count() { return _count; }
50 void increment_count() { _count++; }
693 // Locks an nmethod so its code will not get removed, even if it is a zombie/not_entrant method
694 class nmethodLocker : public StackObj {
695 nmethod* _nm;
696
697 static void lock_nmethod(nmethod* nm); // note: nm can be NULL
698 static void unlock_nmethod(nmethod* nm); // (ditto)
699
700 public:
701 nmethodLocker(address pc); // derive nm from pc
702 nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
703 nmethodLocker() { _nm = NULL; }
704 ~nmethodLocker() { unlock_nmethod(_nm); }
705
706 nmethod* code() { return _nm; }
707 void set_code(nmethod* new_nm) {
708 unlock_nmethod(_nm); // note: This works even if _nm==new_nm.
709 _nm = new_nm;
710 lock_nmethod(_nm);
711 }
712 };
713
714 #endif // SHARE_VM_CODE_NMETHOD_HPP
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