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