1 /*
2 * Copyright (c) 1998, 2010, 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
25 // The Rewriter adds caches to the constant pool and rewrites bytecode indices
26 // pointing into the constant pool for better interpreter performance.
27
28 class Rewriter: public StackObj {
29 private:
30 instanceKlassHandle _klass;
31 constantPoolHandle _pool;
32 objArrayHandle _methods;
33 intArray _cp_map;
34 intStack _cp_cache_map;
35 bool _have_invoke_dynamic;
36
37 void init_cp_map(int length) {
38 _cp_map.initialize(length, -1);
39 // Choose an initial value large enough that we don't get frequent
40 // calls to grow().
41 _cp_cache_map.initialize(length / 2);
42 }
43 int cp_entry_to_cp_cache(int i) { assert(has_cp_cache(i), "oob"); return _cp_map[i]; }
44 bool has_cp_cache(int i) { return (uint)i < (uint)_cp_map.length() && _cp_map[i] >= 0; }
45 int maybe_add_cp_cache_entry(int i) { return has_cp_cache(i) ? _cp_map[i] : add_cp_cache_entry(i); }
46 int add_cp_cache_entry(int cp_index) {
47 assert((cp_index & _secondary_entry_tag) == 0, "bad tag");
48 assert(_cp_map[cp_index] == -1, "not twice on same cp_index");
49 int cache_index = _cp_cache_map.append(cp_index);
50 _cp_map.at_put(cp_index, cache_index);
51 assert(cp_entry_to_cp_cache(cp_index) == cache_index, "");
52 return cache_index;
53 }
54 int add_secondary_cp_cache_entry(int main_cpc_entry) {
55 assert(main_cpc_entry < _cp_cache_map.length(), "must be earlier CP cache entry");
56 int cache_index = _cp_cache_map.append(main_cpc_entry | _secondary_entry_tag);
57 return cache_index;
58 }
59
60 // Access the contents of _cp_cache_map to determine CP cache layout.
61 int cp_cache_entry_pool_index(int cache_index) {
62 int cp_index = _cp_cache_map[cache_index];
63 if ((cp_index & _secondary_entry_tag) != 0)
64 return -1;
65 else
66 return cp_index;
67 }
68 int cp_cache_secondary_entry_main_index(int cache_index) {
69 int cp_index = _cp_cache_map[cache_index];
70 if ((cp_index & _secondary_entry_tag) == 0)
71 return -1;
72 else
73 return (cp_index - _secondary_entry_tag);
74 }
75
76 // All the work goes in here:
77 Rewriter(instanceKlassHandle klass, constantPoolHandle cpool, objArrayHandle methods, TRAPS);
78
79 void compute_index_maps();
80 void make_constant_pool_cache(TRAPS);
81 void scan_method(methodOop m);
82 methodHandle rewrite_jsrs(methodHandle m, TRAPS);
83 void rewrite_Object_init(methodHandle m, TRAPS);
84 void rewrite_member_reference(address bcp, int offset);
85 void rewrite_invokedynamic(address bcp, int offset);
86 void maybe_rewrite_ldc(address bcp, int offset, bool is_wide);
87
88 public:
89 // Driver routine:
90 static void rewrite(instanceKlassHandle klass, TRAPS);
91 static void rewrite(instanceKlassHandle klass, constantPoolHandle cpool, objArrayHandle methods, TRAPS);
92
93 enum {
94 _secondary_entry_tag = nth_bit(30)
95 };
96 };