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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 
35 class MethodComparator {
36  private:
37   static bool args_same(Bytecodes::Code const c_old,  Bytecodes::Code const c_new,
38                         BytecodeStream* const s_old,  BytecodeStream* const s_new,
39                         ConstantPool*   const old_cp, ConstantPool*   const new_cp);
40 
41   static bool pool_constants_same(const int cpi_old, const int cpi_new,
42                                   ConstantPool* const old_cp, ConstantPool* const new_cp);
43 
44   static int check_stack_and_locals_size(Method* const old_method, Method* const new_method);
45 
46  public:
47   // Check if the new method is equivalent to the old one modulo constant pool (EMCP).
48   // Intuitive definition: two versions of the same method are EMCP, if they don't differ
49   // on the source code level. Practically, we check whether the only difference between
50   // method versions is some constantpool indices embedded into the bytecodes, and whether
51   // these indices eventually point to the same constants for both method versions.
52   static bool methods_EMCP(Method* old_method, Method* new_method);
53 
54 };
55 
56 #endif // SHARE_PRIMS_METHODCOMPARATOR_HPP
57