1 /*
   2  * Copyright (c) 1997, 2012, 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_RUNTIME_RELOCATOR_HPP
  26 #define SHARE_VM_RUNTIME_RELOCATOR_HPP
  27 
  28 #include "interpreter/bytecodes.hpp"
  29 #include "oops/method.hpp"
  30 #ifdef TARGET_ARCH_x86
  31 # include "bytes_x86.hpp"
  32 #endif
  33 #ifdef TARGET_ARCH_sparc
  34 # include "bytes_sparc.hpp"
  35 #endif
  36 #ifdef TARGET_ARCH_zero
  37 # include "bytes_zero.hpp"
  38 #endif
  39 #ifdef TARGET_ARCH_arm
  40 # include "bytes_arm.hpp"
  41 #endif
  42 #ifdef TARGET_ARCH_ppc
  43 # include "bytes_ppc.hpp"
  44 #endif
  45 #ifdef TARGET_ARCH_aarch32
  46 # include "bytes_aarch32.hpp"
  47 #endif
  48 
  49 // This code has been converted from the 1.1E java virtual machine
  50 // Thanks to the JavaTopics group for using the code
  51 
  52 class ChangeItem;
  53 
  54 // Callback object for code relocations
  55 class RelocatorListener : public StackObj {
  56  public:
  57   RelocatorListener() {};
  58   virtual void relocated(int bci, int delta, int new_method_size) = 0;
  59 };
  60 
  61 
  62 class Relocator : public ResourceObj {
  63  public:
  64   Relocator(methodHandle method, RelocatorListener* listener);
  65   methodHandle insert_space_at(int bci, int space, u_char inst_buffer[], TRAPS);
  66 
  67   // Callbacks from ChangeItem's
  68   bool handle_code_changes();
  69   bool handle_widen       (int bci, int new_ilen, u_char inst_buffer[]);  // handles general instructions
  70   void push_jump_widen  (int bci, int delta, int new_delta);    // pushes jumps
  71   bool handle_jump_widen  (int bci, int delta);     // handles jumps
  72   bool handle_switch_pad  (int bci, int old_pad, bool is_lookup_switch); // handles table and lookup switches
  73 
  74  private:
  75   unsigned char* _code_array;
  76   int            _code_array_length;
  77   int            _code_length;
  78   unsigned char* _compressed_line_number_table;
  79   int            _compressed_line_number_table_size;
  80   methodHandle   _method;
  81   u_char         _overwrite[3];             // stores overwritten bytes for shrunken instructions
  82 
  83   GrowableArray<ChangeItem*>* _changes;
  84 
  85   unsigned char* code_array() const         { return _code_array; }
  86   void set_code_array(unsigned char* array) { _code_array = array; }
  87 
  88   int code_length() const                   { return _code_length; }
  89   void set_code_length(int length)          { _code_length = length; }
  90 
  91   int code_array_length() const             { return _code_array_length; }
  92   void set_code_array_length(int length)    { _code_array_length = length; }
  93 
  94   unsigned char* compressed_line_number_table() const         { return _compressed_line_number_table; }
  95   void set_compressed_line_number_table(unsigned char* table) { _compressed_line_number_table = table; }
  96 
  97   int compressed_line_number_table_size() const               { return _compressed_line_number_table_size; }
  98   void set_compressed_line_number_table_size(int size)        { _compressed_line_number_table_size = size; }
  99 
 100   methodHandle method() const               { return _method; }
 101   void set_method(methodHandle method)      { _method = method; }
 102 
 103   // This will return a raw bytecode, which is possibly rewritten.
 104   Bytecodes::Code code_at(int bci) const          { return (Bytecodes::Code) code_array()[bci]; }
 105   void code_at_put(int bci, Bytecodes::Code code) { code_array()[bci] = (char) code; }
 106 
 107   // get and set signed integers in the code_array
 108   inline int   int_at(int bci) const               { return Bytes::get_Java_u4(&code_array()[bci]); }
 109   inline void  int_at_put(int bci, int value)      { Bytes::put_Java_u4(&code_array()[bci], value); }
 110 
 111   // get and set signed shorts in the code_array
 112   inline short short_at(int bci) const            { return (short)Bytes::get_Java_u2(&code_array()[bci]); }
 113   inline void  short_at_put(int bci, short value) { Bytes::put_Java_u2((address) &code_array()[bci], value); }
 114 
 115   // get the address of in the code_array
 116   inline char* addr_at(int bci) const             { return (char*) &code_array()[bci]; }
 117 
 118   int  instruction_length_at(int bci)             { return Bytecodes::length_at(NULL, code_array() + bci); }
 119 
 120   // Helper methods
 121   int  align(int n) const                          { return (n+3) & ~3; }
 122   int  code_slop_pct() const                       { return 25; }
 123   bool is_opcode_lookupswitch(Bytecodes::Code bc);
 124 
 125   // basic relocation methods
 126   bool relocate_code         (int bci, int ilen, int delta);
 127   void change_jumps          (int break_bci, int delta);
 128   void change_jump           (int bci, int offset, bool is_short, int break_bci, int delta);
 129   void adjust_exception_table(int bci, int delta);
 130   void adjust_line_no_table  (int bci, int delta);
 131   void adjust_local_var_table(int bci, int delta);
 132   void adjust_stack_map_table(int bci, int delta);
 133   int  get_orig_switch_pad   (int bci, bool is_lookup_switch);
 134   int  rc_instr_len          (int bci);
 135   bool expand_code_array     (int delta);
 136 
 137   // Callback support
 138   RelocatorListener *_listener;
 139   void notify(int bci, int delta, int new_code_length) {
 140     if (_listener != NULL)
 141       _listener->relocated(bci, delta, new_code_length);
 142   }
 143 };
 144 
 145 #endif // SHARE_VM_RUNTIME_RELOCATOR_HPP