1 /* 2 * Copyright (c) 1998, 2015, 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 #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 instanceKlassHandle _klass; 38 constantPoolHandle _pool; 39 Array<Method*>* _methods; 40 intArray _cp_map; 41 intStack _cp_cache_map; // for Methodref, Fieldref, 42 // InterfaceMethodref and InvokeDynamic 43 intArray _reference_map; // maps from cp index to resolved_refs index (or -1) 44 intStack _resolved_references_map; // for strings, methodHandle, methodType 45 intStack _invokedynamic_references_map; // for invokedynamic resolved refs 46 intArray _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 intStack _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.initialize(length, -1); 62 // Choose an initial value large enough that we don't get frequent 63 // calls to grow(). 64 _cp_cache_map.initialize(length/2); 65 // Also cache resolved objects, in another different cache. 66 _reference_map.initialize(length, -1); 67 _resolved_references_map.initialize(length/2); 68 _invokedynamic_references_map.initialize(length/2); 69 _resolved_reference_limit = -1; 70 _first_iteration_cp_cache_limit = -1; 71 72 // invokedynamic specific fields 73 _invokedynamic_cp_cache_map.initialize(length/4); 74 _patch_invokedynamic_bcps = new GrowableArray<address>(length/4); 75 _patch_invokedynamic_refs = new GrowableArray<int>(length/4); 76 } 77 78 int _first_iteration_cp_cache_limit; 79 void record_map_limits() { 80 // Record initial size of the two arrays generated for the CP cache 81 // relative to walking the constant pool. 82 _first_iteration_cp_cache_limit = _cp_cache_map.length(); 83 _resolved_reference_limit = _resolved_references_map.length(); 84 } 85 86 int cp_cache_delta() { 87 // How many cp cache entries were added since recording map limits after 88 // cp cache initialization? 89 assert(_first_iteration_cp_cache_limit != -1, "only valid after first iteration"); 90 return _cp_cache_map.length() - _first_iteration_cp_cache_limit; 91 } 92 93 int cp_entry_to_cp_cache(int i) { assert(has_cp_cache(i), "oob"); return _cp_map[i]; } 94 bool has_cp_cache(int i) { return (uint)i < (uint)_cp_map.length() && _cp_map[i] >= 0; } 95 96 int add_map_entry(int cp_index, intArray* cp_map, intStack* cp_cache_map) { 97 assert(cp_map->at(cp_index) == -1, "not twice on same cp_index"); 98 int cache_index = cp_cache_map->append(cp_index); 99 cp_map->at_put(cp_index, cache_index); 100 return cache_index; 101 } 102 103 int add_cp_cache_entry(int cp_index) { 104 assert(_pool->tag_at(cp_index).value() != JVM_CONSTANT_InvokeDynamic, "use indy version"); 105 assert(_first_iteration_cp_cache_limit == -1, "do not add cache entries after first iteration"); 106 int cache_index = add_map_entry(cp_index, &_cp_map, &_cp_cache_map); 107 assert(cp_entry_to_cp_cache(cp_index) == cache_index, ""); 108 assert(cp_cache_entry_pool_index(cache_index) == cp_index, ""); 109 return cache_index; 110 } 111 112 int add_invokedynamic_cp_cache_entry(int cp_index) { 113 assert(_pool->tag_at(cp_index).value() == JVM_CONSTANT_InvokeDynamic, "use non-indy version"); 114 assert(_first_iteration_cp_cache_limit >= 0, "add indy cache entries after first iteration"); 115 // add to the invokedynamic index map. 116 int cache_index = _invokedynamic_cp_cache_map.append(cp_index); 117 // do not update _cp_map, since the mapping is one-to-many 118 assert(invokedynamic_cp_cache_entry_pool_index(cache_index) == cp_index, ""); 119 // this index starts at one but in the bytecode it's appended to the end. 120 return cache_index + _first_iteration_cp_cache_limit; 121 } 122 123 int invokedynamic_cp_cache_entry_pool_index(int cache_index) { 124 int cp_index = _invokedynamic_cp_cache_map[cache_index]; 125 return cp_index; 126 } 127 128 // add a new CP cache entry beyond the normal cache for the special case of 129 // invokespecial with InterfaceMethodref as cpool operand. 130 int add_invokespecial_cp_cache_entry(int cp_index) { 131 assert(_first_iteration_cp_cache_limit >= 0, "add these special cache entries after first iteration"); 132 // Don't add InterfaceMethodref if it already exists at the end. 133 for (int i = _first_iteration_cp_cache_limit; i < _cp_cache_map.length(); i++) { 134 if (cp_cache_entry_pool_index(i) == cp_index) { 135 return i; 136 } 137 } 138 int cache_index = _cp_cache_map.append(cp_index); 139 assert(cache_index >= _first_iteration_cp_cache_limit, ""); 140 // do not update _cp_map, since the mapping is one-to-many 141 assert(cp_cache_entry_pool_index(cache_index) == cp_index, ""); 142 return cache_index; 143 } 144 145 int cp_entry_to_resolved_references(int cp_index) const { 146 assert(has_entry_in_resolved_references(cp_index), "oob"); 147 return _reference_map[cp_index]; 148 } 149 bool has_entry_in_resolved_references(int cp_index) const { 150 return (uint)cp_index < (uint)_reference_map.length() && _reference_map[cp_index] >= 0; 151 } 152 153 // add a new entry to the resolved_references map 154 int add_resolved_references_entry(int cp_index) { 155 int ref_index = add_map_entry(cp_index, &_reference_map, &_resolved_references_map); 156 assert(cp_entry_to_resolved_references(cp_index) == ref_index, ""); 157 return ref_index; 158 } 159 160 // add a new entries to the resolved_references map (for invokedynamic and invokehandle only) 161 int add_invokedynamic_resolved_references_entries(int cp_index, int cache_index) { 162 assert(_resolved_reference_limit >= 0, "must add indy refs after first iteration"); 163 int ref_index = -1; 164 for (int entry = 0; entry < ConstantPoolCacheEntry::_indy_resolved_references_entries; entry++) { 165 const int index = _resolved_references_map.append(cp_index); // many-to-one 166 assert(index >= _resolved_reference_limit, ""); 167 if (entry == 0) { 168 ref_index = index; 169 } 170 assert((index - entry) == ref_index, "entries must be consecutive"); 171 _invokedynamic_references_map.at_put_grow(index, cache_index, -1); 172 } 173 return ref_index; 174 } 175 176 int resolved_references_entry_to_pool_index(int ref_index) { 177 int cp_index = _resolved_references_map[ref_index]; 178 return cp_index; 179 } 180 181 // Access the contents of _cp_cache_map to determine CP cache layout. 182 int cp_cache_entry_pool_index(int cache_index) { 183 int cp_index = _cp_cache_map[cache_index]; 184 return cp_index; 185 } 186 187 // All the work goes in here: 188 Rewriter(instanceKlassHandle klass, const constantPoolHandle& cpool, Array<Method*>* methods, TRAPS); 189 190 void compute_index_maps(); 191 void make_constant_pool_cache(TRAPS); 192 void scan_method(Method* m, bool reverse, bool* invokespecial_error); 193 void rewrite_Object_init(methodHandle m, TRAPS); 194 void rewrite_member_reference(address bcp, int offset, bool reverse); 195 void maybe_rewrite_invokehandle(address opc, int cp_index, int cache_index, bool reverse); 196 void rewrite_invokedynamic(address bcp, int offset, bool reverse); 197 void maybe_rewrite_ldc(address bcp, int offset, bool is_wide, bool reverse); 198 void rewrite_invokespecial(address bcp, int offset, bool reverse, bool* invokespecial_error); 199 200 void patch_invokedynamic_bytecodes(); 201 202 // Do all the work. 203 void rewrite_bytecodes(TRAPS); 204 205 // Revert bytecodes in case of an exception. 206 void restore_bytecodes(); 207 208 static methodHandle rewrite_jsrs(methodHandle m, TRAPS); 209 public: 210 // Driver routine: 211 static void rewrite(instanceKlassHandle klass, TRAPS); 212 }; 213 214 #endif // SHARE_VM_INTERPRETER_REWRITER_HPP