1 /*
2 * Copyright (c) 1998, 2017, 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_VM_INTERPRETER_REWRITER_HPP
26 #define SHARE_VM_INTERPRETER_REWRITER_HPP
27
28 #include "memory/allocation.hpp"
29 #include "runtime/handles.inline.hpp"
30 #include "utilities/growableArray.hpp"
31
32 // The Rewriter adds caches to the constant pool and rewrites bytecode indices
33 // pointing into the constant pool for better interpreter performance.
34
35 class Rewriter: public StackObj {
36 private:
37 InstanceKlass* _klass;
38 constantPoolHandle _pool;
39 Array<Method*>* _methods;
40 GrowableArray<int> _cp_map;
41 GrowableArray<int> _cp_cache_map; // for Methodref, Fieldref,
42 // InterfaceMethodref and InvokeDynamic
43 GrowableArray<int> _reference_map; // maps from cp index to resolved_refs index (or -1)
44 GrowableArray<int> _resolved_references_map; // for strings, methodHandle, methodType
45 GrowableArray<int> _invokedynamic_references_map; // for invokedynamic resolved refs
46 GrowableArray<int> _method_handle_invokers;
47 int _resolved_reference_limit;
48
49 // For mapping invokedynamic bytecodes, which are discovered during method
50 // scanning. The invokedynamic entries are added at the end of the cpCache.
51 // If there are any invokespecial/InterfaceMethodref special case bytecodes,
52 // these entries are added before invokedynamic entries so that the
53 // invokespecial bytecode 16 bit index doesn't overflow.
54 GrowableArray<int> _invokedynamic_cp_cache_map;
55
56 // For patching.
57 GrowableArray<address>* _patch_invokedynamic_bcps;
58 GrowableArray<int>* _patch_invokedynamic_refs;
59
60 void init_maps(int length) {
61 _cp_map.trunc_to(0);
62 _cp_map.at_grow(length, -1);
63
64 _cp_cache_map.trunc_to(0);
65 // Also cache resolved objects, in another different cache.
66 _reference_map.trunc_to(0);
67 _reference_map.at_grow(length, -1);
68
69 _method_handle_invokers.trunc_to(0);
70 _resolved_references_map.trunc_to(0);
71 _invokedynamic_references_map.trunc_to(0);
72 _resolved_reference_limit = -1;
73 _first_iteration_cp_cache_limit = -1;
74
75 // invokedynamic specific fields
76 _invokedynamic_cp_cache_map.trunc_to(0);
77 _patch_invokedynamic_bcps = new GrowableArray<address>(length / 4);
78 _patch_invokedynamic_refs = new GrowableArray<int>(length / 4);
79 }
80
81 int _first_iteration_cp_cache_limit;
82 void record_map_limits() {
83 // Record initial size of the two arrays generated for the CP cache
84 // relative to walking the constant pool.
85 _first_iteration_cp_cache_limit = _cp_cache_map.length();
86 _resolved_reference_limit = _resolved_references_map.length();
87 }
88
89 int cp_cache_delta() {
90 // How many cp cache entries were added since recording map limits after
91 // cp cache initialization?
92 assert(_first_iteration_cp_cache_limit != -1, "only valid after first iteration");
93 return _cp_cache_map.length() - _first_iteration_cp_cache_limit;
94 }
95
96 int cp_entry_to_cp_cache(int i) { assert(has_cp_cache(i), "oob"); return _cp_map.at(i); }
97 bool has_cp_cache(int i) { return (uint) i < (uint) _cp_map.length() && _cp_map.at(i) >= 0; }
98
99 int add_map_entry(int cp_index, GrowableArray<int>* cp_map, GrowableArray<int>* cp_cache_map) {
100 assert(cp_map->at(cp_index) == -1, "not twice on same cp_index");
101 int cache_index = cp_cache_map->append(cp_index);
102 cp_map->at_put(cp_index, cache_index);
103 return cache_index;
104 }
105
106 int add_cp_cache_entry(int cp_index) {
107 assert(_pool->tag_at(cp_index).value() != JVM_CONSTANT_InvokeDynamic, "use indy version");
108 assert(_first_iteration_cp_cache_limit == -1, "do not add cache entries after first iteration");
109 int cache_index = add_map_entry(cp_index, &_cp_map, &_cp_cache_map);
110 assert(cp_entry_to_cp_cache(cp_index) == cache_index, "");
111 assert(cp_cache_entry_pool_index(cache_index) == cp_index, "");
112 return cache_index;
113 }
114
115 int add_invokedynamic_cp_cache_entry(int cp_index) {
116 assert(_pool->tag_at(cp_index).value() == JVM_CONSTANT_InvokeDynamic, "use non-indy version");
117 assert(_first_iteration_cp_cache_limit >= 0, "add indy cache entries after first iteration");
118 // add to the invokedynamic index map.
119 int cache_index = _invokedynamic_cp_cache_map.append(cp_index);
120 // do not update _cp_map, since the mapping is one-to-many
121 assert(invokedynamic_cp_cache_entry_pool_index(cache_index) == cp_index, "");
122 // this index starts at one but in the bytecode it's appended to the end.
123 return cache_index + _first_iteration_cp_cache_limit;
124 }
125
126 int invokedynamic_cp_cache_entry_pool_index(int cache_index) {
127 int cp_index = _invokedynamic_cp_cache_map.at(cache_index);
128 return cp_index;
129 }
130
131 // add a new CP cache entry beyond the normal cache for the special case of
132 // invokespecial with InterfaceMethodref as cpool operand.
133 int add_invokespecial_cp_cache_entry(int cp_index) {
134 assert(_first_iteration_cp_cache_limit >= 0, "add these special cache entries after first iteration");
135 // Don't add InterfaceMethodref if it already exists at the end.
136 for (int i = _first_iteration_cp_cache_limit; i < _cp_cache_map.length(); i++) {
137 if (cp_cache_entry_pool_index(i) == cp_index) {
138 return i;
139 }
140 }
141 int cache_index = _cp_cache_map.append(cp_index);
142 assert(cache_index >= _first_iteration_cp_cache_limit, "");
143 // do not update _cp_map, since the mapping is one-to-many
144 assert(cp_cache_entry_pool_index(cache_index) == cp_index, "");
145 return cache_index;
146 }
147
148 int cp_entry_to_resolved_references(int cp_index) const {
149 assert(has_entry_in_resolved_references(cp_index), "oob");
150 return _reference_map.at(cp_index);
151 }
152 bool has_entry_in_resolved_references(int cp_index) const {
153 return (uint) cp_index < (uint) _reference_map.length() && _reference_map.at(cp_index) >= 0;
154 }
155
156 // add a new entry to the resolved_references map
157 int add_resolved_references_entry(int cp_index) {
158 int ref_index = add_map_entry(cp_index, &_reference_map, &_resolved_references_map);
159 assert(cp_entry_to_resolved_references(cp_index) == ref_index, "");
160 return ref_index;
161 }
162
163 // add a new entries to the resolved_references map (for invokedynamic and invokehandle only)
164 int add_invokedynamic_resolved_references_entries(int cp_index, int cache_index) {
165 assert(_resolved_reference_limit >= 0, "must add indy refs after first iteration");
166 int ref_index = -1;
167 for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) {
168 const int index = _resolved_references_map.append(cp_index); // many-to-one
169 assert(index >= _resolved_reference_limit, "");
170 if (entry == 0) {
171 ref_index = index;
172 }
173 assert((index - entry) == ref_index, "entries must be consecutive");
174 _invokedynamic_references_map.at_put_grow(index, cache_index, -1);
175 }
176 return ref_index;
177 }
178
179 int resolved_references_entry_to_pool_index(int ref_index) {
180 int cp_index = _resolved_references_map.at(ref_index);
181 return cp_index;
182 }
183
184 // Access the contents of _cp_cache_map to determine CP cache layout.
185 int cp_cache_entry_pool_index(int cache_index) {
186 int cp_index = _cp_cache_map.at(cache_index);
187 return cp_index;
188 }
189
190 // All the work goes in here:
191 Rewriter(InstanceKlass* klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS);
192
193 void compute_index_maps();
194 void make_constant_pool_cache(TRAPS);
195 void scan_method(Method* m, bool reverse, bool* invokespecial_error);
196 void rewrite_Object_init(const methodHandle& m, TRAPS);
197 void rewrite_member_reference(address bcp, int offset, bool reverse);
198 void maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse);
199 void rewrite_invokedynamic(address bcp, int offset, bool reverse);
200 void maybe_rewrite_ldc(address bcp, int offset, bool is_wide, bool reverse);
201 void rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error);
202
203 void patch_invokedynamic_bytecodes();
204
205 // Do all the work.
206 void rewrite_bytecodes(TRAPS);
207
208 // Revert bytecodes in case of an exception.
209 void restore_bytecodes();
210
211 static methodHandle rewrite_jsrs(const methodHandle& m, TRAPS);
212 public:
213 // Driver routine:
214 static void rewrite(InstanceKlass* klass, TRAPS);
215 };
216
217 #endif // SHARE_VM_INTERPRETER_REWRITER_HPP