1/*
2 * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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24
25#ifndef SHARE_PRIMS_METHODCOMPARATOR_HPP
26#define SHARE_PRIMS_METHODCOMPARATOR_HPP
27
28#include "interpreter/bytecodeStream.hpp"
29#include "oops/constantPool.hpp"
30#include "oops/method.hpp"
31
32// methodComparator provides an interface for determining if methods of
33// different versions of classes are equivalent or switchable
34
35class MethodComparator {
36 private:
37 static BytecodeStream *_s_old, *_s_new;
38 static ConstantPool* _old_cp;
39 static ConstantPool* _new_cp;
40
41 static bool args_same(Bytecodes::Code c_old, Bytecodes::Code c_new);
42 static bool pool_constants_same(int cpi_old, int cpi_new);
43 static int check_stack_and_locals_size(Method* old_method, Method* new_method);
44
45 public:
46 // Check if the new method is equivalent to the old one modulo constant pool (EMCP).
47 // Intuitive definition: two versions of the same method are EMCP, if they don't differ
48 // on the source code level. Practically, we check whether the only difference between
49 // method versions is some constantpool indices embedded into the bytecodes, and whether
50 // these indices eventually point to the same constants for both method versions.
51 static bool methods_EMCP(Method* old_method, Method* new_method);
52
53};
54
55#endif // SHARE_PRIMS_METHODCOMPARATOR_HPP
56