duke@435: /*
coleenp@4037:  * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #ifndef SHARE_VM_PRIMS_METHODCOMPARATOR_HPP
stefank@2314: #define SHARE_VM_PRIMS_METHODCOMPARATOR_HPP
stefank@2314: 
stefank@2314: #include "interpreter/bytecodeStream.hpp"
coleenp@4037: #include "oops/constantPool.hpp"
coleenp@4037: #include "oops/method.hpp"
stefank@2314: 
duke@435: class BciMap;
duke@435: 
duke@435: // methodComparator provides an interface for determining if methods of
duke@435: // different versions of classes are equivalent or switchable
duke@435: 
duke@435: class MethodComparator {
duke@435:  private:
duke@435:   static BytecodeStream *_s_old, *_s_new;
coleenp@4037:   static ConstantPool* _old_cp;
coleenp@4037:   static ConstantPool* _new_cp;
duke@435:   static BciMap *_bci_map;
duke@435:   static bool _switchable_test;
duke@435:   static GrowableArray<int> *_fwd_jmps;
duke@435: 
duke@435:   static bool args_same(Bytecodes::Code c_old, Bytecodes::Code c_new);
jrose@2268:   static bool pool_constants_same(int cpi_old, int cpi_new);
coleenp@4037:   static int check_stack_and_locals_size(Method* old_method, Method* new_method);
duke@435: 
duke@435:  public:
duke@435:   // Check if the new method is equivalent to the old one modulo constant pool (EMCP).
duke@435:   // Intuitive definition: two versions of the same method are EMCP, if they don't differ
duke@435:   // on the source code level. Practically, we check whether the only difference between
duke@435:   // method versions is some constantpool indices embedded into the bytecodes, and whether
duke@435:   // these indices eventually point to the same constants for both method versions.
coleenp@4037:   static bool methods_EMCP(Method* old_method, Method* new_method);
duke@435: 
coleenp@4037:   static bool methods_switchable(Method* old_method, Method* new_method, BciMap &bci_map);
duke@435: };
duke@435: 
duke@435: 
duke@435: // ByteCode Index Map. For two versions of the same method, where the new version may contain
duke@435: // fragments not found in the old version, provides a mapping from an index of a bytecode in
duke@435: // the old method to the index of the same bytecode in the new method.
duke@435: 
duke@435: class BciMap {
duke@435:  private:
duke@435:   int *_old_bci, *_new_st_bci, *_new_end_bci;
duke@435:   int _cur_size, _cur_pos;
duke@435:   int _pos;
duke@435: 
duke@435:  public:
duke@435:   BciMap() {
duke@435:     _cur_size = 50;
duke@435:     _old_bci = (int*) malloc(sizeof(int) * _cur_size);
duke@435:     _new_st_bci = (int*) malloc(sizeof(int) * _cur_size);
duke@435:     _new_end_bci = (int*) malloc(sizeof(int) * _cur_size);
duke@435:     _cur_pos = 0;
duke@435:   }
duke@435: 
duke@435:   ~BciMap() {
duke@435:     free(_old_bci);
duke@435:     free(_new_st_bci);
duke@435:     free(_new_end_bci);
duke@435:   }
duke@435: 
duke@435:   // Store the position of an added fragment, e.g.
duke@435:   //
duke@435:   //                              |<- old_bci
duke@435:   // -----------------------------------------
duke@435:   // Old method   |invokevirtual 5|aload 1|...
duke@435:   // -----------------------------------------
duke@435:   //
duke@435:   //                                 |<- new_st_bci          |<- new_end_bci
duke@435:   // --------------------------------------------------------------------
duke@435:   // New method       |invokevirual 5|aload 2|invokevirtual 6|aload 1|...
duke@435:   // --------------------------------------------------------------------
duke@435:   //                                 ^^^^^^^^^^^^^^^^^^^^^^^^
duke@435:   //                                    Added fragment
duke@435: 
duke@435:   void store_fragment_location(int old_bci, int new_st_bci, int new_end_bci) {
duke@435:     if (_cur_pos == _cur_size) {
duke@435:       _cur_size += 10;
duke@435:       _old_bci = (int*) realloc(_old_bci, sizeof(int) * _cur_size);
duke@435:       _new_st_bci = (int*) realloc(_new_st_bci, sizeof(int) * _cur_size);
duke@435:       _new_end_bci = (int*) realloc(_new_end_bci, sizeof(int) * _cur_size);
duke@435:     }
duke@435:     _old_bci[_cur_pos] = old_bci;
duke@435:     _new_st_bci[_cur_pos] = new_st_bci;
duke@435:     _new_end_bci[_cur_pos] = new_end_bci;
duke@435:     _cur_pos++;
duke@435:   }
duke@435: 
duke@435:   int new_bci_for_old(int old_bci) {
duke@435:     if (_cur_pos == 0 || old_bci < _old_bci[0]) return old_bci;
duke@435:     _pos = 1;
duke@435:     while (_pos < _cur_pos && old_bci >= _old_bci[_pos])
duke@435:       _pos++;
duke@435:     return _new_end_bci[_pos-1] + (old_bci - _old_bci[_pos-1]);
duke@435:   }
duke@435: 
duke@435:   // Test if two indexes - one in the old method and another in the new one - correspond
duke@435:   // to the same bytecode
duke@435:   bool old_and_new_locations_same(int old_dest_bci, int new_dest_bci) {
duke@435:     if (new_bci_for_old(old_dest_bci) == new_dest_bci)
duke@435:       return true;
duke@435:     else if (_old_bci[_pos-1] == old_dest_bci)
duke@435:       return (new_dest_bci == _new_st_bci[_pos-1]);
duke@435:     else return false;
duke@435:   }
duke@435: };
stefank@2314: 
stefank@2314: #endif // SHARE_VM_PRIMS_METHODCOMPARATOR_HPP