1 /*
2 * Copyright (c) 2012, 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.
22 *
23 */
24 #ifndef SHARE_VM_MEMORY_METASPACE_SHARED_HPP
25 #define SHARE_VM_MEMORY_METASPACE_SHARED_HPP
26
27 #include "memory/allocation.hpp"
28 #include "memory/memRegion.hpp"
29 #include "runtime/virtualspace.hpp"
30 #include "utilities/exceptions.hpp"
31 #include "utilities/macros.hpp"
32
33 class FileMapInfo;
34
35 // Class Data Sharing Support
36 class MetaspaceShared : AllStatic {
37
38 // CDS support
39 static ReservedSpace* _shared_rs;
40 static int _max_alignment;
41
42 public:
43 enum {
44 vtbl_list_size = 17, // number of entries in the shared space vtable list.
45 num_virtuals = 200 // maximum number of virtual functions
46 // If virtual functions are added to Metadata,
47 // this number needs to be increased. Also,
48 // SharedMiscCodeSize will need to be increased.
49 };
50
51 enum {
52 ro = 0, // read-only shared space in the heap
53 rw = 1, // read-write shared space in the heap
54 md = 2, // miscellaneous data for initializing tables, etc.
55 mc = 3, // miscellaneous code - vtable replacement.
56 n_regions = 4
57 };
58
59 // Accessor functions to save shared space created for metadata, which has
60 // extra space allocated at the end for miscellaneous data and code.
61 static void set_max_alignment(int alignment) {
62 CDS_ONLY(_max_alignment = alignment);
63 }
64
65 static int max_alignment() {
66 CDS_ONLY(return _max_alignment);
67 NOT_CDS(return 0);
68 }
69
70 static void preload_and_dump(TRAPS) NOT_CDS_RETURN;
71
72 static ReservedSpace* shared_rs() {
73 CDS_ONLY(return _shared_rs);
74 NOT_CDS(return NULL);
75 }
76
77 static void set_shared_rs(ReservedSpace* rs) {
78 CDS_ONLY(_shared_rs = rs;)
79 }
80
81 static bool map_shared_spaces(FileMapInfo* mapinfo) NOT_CDS_RETURN_(false);
82 static void initialize_shared_spaces() NOT_CDS_RETURN;
83
84 // Return true if given address is in the mapped shared space.
85 static bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);
86
87 static void generate_vtable_methods(void** vtbl_list,
88 void** vtable,
89 char** md_top, char* md_end,
90 char** mc_top, char* mc_end);
91 static void serialize(SerializeClosure* sc);
92
93 // JVM/TI RedefineClasses() support:
94 // Remap the shared readonly space to shared readwrite, private if
95 // sharing is enabled. Simply returns true if sharing is not enabled
96 // or if the remapping has already been done by a prior call.
97 static bool remap_shared_readonly_as_readwrite() NOT_CDS_RETURN_(true);
98
99 static void print_shared_spaces();
100 };
101 #endif // SHARE_VM_MEMORY_METASPACE_SHARED_HPP