1/*
2 * Copyright (c) 1998, 2019, 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.
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23 */
24
25#ifndef SHARE_OOPS_COMPILEDICHOLDER_HPP
26#define SHARE_OOPS_COMPILEDICHOLDER_HPP
27
28#include "oops/oop.hpp"
29#include "utilities/macros.hpp"
30#include "oops/klass.hpp"
31#include "oops/method.hpp"
32
33// A CompiledICHolder* is a helper object for the inline cache implementation.
34// It holds:
35// (1) (method+klass pair) when converting from compiled to an interpreted call
36// (2) (klass+klass pair) when calling itable stub from megamorphic compiled call
37//
38// These are always allocated in the C heap and are freed during a
39// safepoint by the ICBuffer logic. It's unsafe to free them earlier
40// since they might be in use.
41//
42
43
44class CompiledICHolder : public CHeapObj<mtCompiler> {
45 friend class VMStructs;
46 private:
47 static volatile int _live_count; // allocated
48 static volatile int _live_not_claimed_count; // allocated but not yet in use so not
49 // reachable by iterating over nmethods
50
51 Metadata* _holder_metadata;
52 Klass* _holder_klass; // to avoid name conflict with oopDesc::_klass
53 CompiledICHolder* _next;
54 bool _is_metadata_method;
55
56 public:
57 // Constructor
58 CompiledICHolder(Metadata* metadata, Klass* klass, bool is_method = true);
59 ~CompiledICHolder() NOT_DEBUG_RETURN;
60
61 static int live_count() { return _live_count; }
62 static int live_not_claimed_count() { return _live_not_claimed_count; }
63
64 // accessors
65 Klass* holder_klass() const { return _holder_klass; }
66 Metadata* holder_metadata() const { return _holder_metadata; }
67
68 static int holder_metadata_offset() { return offset_of(CompiledICHolder, _holder_metadata); }
69 static int holder_klass_offset() { return offset_of(CompiledICHolder, _holder_klass); }
70
71 CompiledICHolder* next() { return _next; }
72 void set_next(CompiledICHolder* n) { _next = n; }
73
74 inline bool is_loader_alive() {
75 Klass* k = _is_metadata_method ? ((Method*)_holder_metadata)->method_holder() : (Klass*)_holder_metadata;
76 if (!k->is_loader_alive()) {
77 return false;
78 }
79 if (!_holder_klass->is_loader_alive()) {
80 return false;
81 }
82 return true;
83 }
84
85 // Verify
86 void verify_on(outputStream* st);
87
88 // Printing
89 void print_on(outputStream* st) const;
90 void print_value_on(outputStream* st) const;
91
92 const char* internal_name() const { return "{compiledICHolder}"; }
93
94 void claim() NOT_DEBUG_RETURN;
95};
96
97#endif // SHARE_OOPS_COMPILEDICHOLDER_HPP
98