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 /*

  * Copyright (c) 2003, 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.

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  */

 #ifndef SHARE_VM_OOPS_CONSTMETHODOOP_HPP

 #define SHARE_VM_OOPS_CONSTMETHODOOP_HPP

 #include "oops/oop.hpp"

 // An ConstMethod* represents portions of a Java method which

 // do not vary.

 //

 // Memory layout (each line represents a word). Note that most

 // applications load thousands of methods, so keeping the size of this

 // structure small has a big impact on footprint.

 //

 // |------------------------------------------------------|

 // | header                                               |

 // | klass                                                |

 // |------------------------------------------------------|

 // | fingerprint 1                                        |

 // | fingerprint 2                                        |

 // | constants                      (oop)                 |

 // | stackmap_data                  (oop)                 |

 // | constMethod_size                                     |

 // | interp_kind  | flags    | code_size                  |

 // | name index              | signature index            |

 // | method_idnum            | generic_signature_index    |

 // |------------------------------------------------------|

 // |                                                      |

 // | byte codes                                           |

 // |                                                      |

 // |------------------------------------------------------|

 // | compressed linenumber table                          |

 // |  (see class CompressedLineNumberReadStream)          |

 // |  (note that length is unknown until decompressed)    |

 // |  (access flags bit tells whether table is present)   |

 // |  (indexed from start of ConstMethod*)              |

 // |  (elements not necessarily sorted!)                  |

 // |------------------------------------------------------|

 // | localvariable table elements + length (length last)  |

 // |  (length is u2, elements are 6-tuples of u2)         |

 // |  (see class LocalVariableTableElement)               |

 // |  (access flags bit tells whether table is present)   |

 // |  (indexed from end of ConstMethod*)                |

 // |------------------------------------------------------|

 // | exception table + length (length last)               |

 // |  (length is u2, elements are 4-tuples of u2)         |

 // |  (see class ExceptionTableElement)                   |

 // |  (access flags bit tells whether table is present)   |

 // |  (indexed from end of ConstMethod*)                |

 // |------------------------------------------------------|

 // | checked exceptions elements + length (length last)   |

 // |  (length is u2, elements are u2)                     |

 // |  (see class CheckedExceptionElement)                 |

 // |  (access flags bit tells whether table is present)   |

 // |  (indexed from end of ConstMethod*)                |

 // |------------------------------------------------------|

 // Utitily class decribing elements in checked exceptions table inlined in Method*.

 class CheckedExceptionElement VALUE_OBJ_CLASS_SPEC {

  public:

   u2 class_cp_index;

 };

 // Utitily class decribing elements in local variable table inlined in Method*.

 class LocalVariableTableElement VALUE_OBJ_CLASS_SPEC {

  public:

   u2 start_bci;

   u2 length;

   u2 name_cp_index;

   u2 descriptor_cp_index;

   u2 signature_cp_index;

   u2 slot;

 };

 // Utitily class describing elements in exception table

 class ExceptionTableElement VALUE_OBJ_CLASS_SPEC {

  public:

   u2 start_pc;

   u2 end_pc;

   u2 handler_pc;

   u2 catch_type_index;

 };

 class ConstMethod : public MetaspaceObj {

   friend class VMStructs;

 private:

   enum {

     _has_linenumber_table = 1,

     _has_checked_exceptions = 2,

     _has_localvariable_table = 4,

     _has_exception_table = 8

   };

   // Bit vector of signature

   // Callers interpret 0=not initialized yet and

   // -1=too many args to fix, must parse the slow way.

   // The real initial value is special to account for nonatomicity of 64 bit

   // loads and stores.  This value may updated and read without a lock by

   // multiple threads, so is volatile.

   volatile uint64_t _fingerprint;

   ConstantPool*     _constants;                  // Constant pool

   // Raw stackmap data for the method

   Array<u1>*        _stackmap_data;

   int               _constMethod_size;

   jbyte             _interpreter_kind;

   jbyte             _flags;

   // Size of Java bytecodes allocated immediately after Method*.

   u2                _code_size;

   u2                _name_index;                 // Method name (index in constant pool)

   u2                _signature_index;            // Method signature (index in constant pool)

   u2                _method_idnum;               // unique identification number for the method within the class

                                                  // initially corresponds to the index into the methods array.

                                                  // but this may change with redefinition

   u2                _generic_signature_index;    // Generic signature (index in constant pool, 0 if absent)

   // Constructor

   ConstMethod(int byte_code_size,

                      int compressed_line_number_size,

                      int localvariable_table_length,

                      int exception_table_length,

                      int checked_exceptions_length,

                      int size);

 public:

   static ConstMethod* allocate(ClassLoaderData* loader_data,

                                  int byte_code_size,

                                  int compressed_line_number_size,

                                  int localvariable_table_length,

                                  int exception_table_length,

                                  int checked_exceptions_length,

                                  TRAPS);

   bool is_constMethod() const { return true; }

   // Inlined tables

   void set_inlined_tables_length(int checked_exceptions_len,

                                  int compressed_line_number_size,

                                  int localvariable_table_len,

                                  int exception_table_len);

   bool has_linenumber_table() const

     { return (_flags & _has_linenumber_table) != 0; }

   bool has_checked_exceptions() const

     { return (_flags & _has_checked_exceptions) != 0; }

   bool has_localvariable_table() const

     { return (_flags & _has_localvariable_table) != 0; }

   bool has_exception_handler() const

     { return (_flags & _has_exception_table) != 0; }

   void set_interpreter_kind(int kind)      { _interpreter_kind = kind; }

   int  interpreter_kind(void) const        { return _interpreter_kind; }

   // constant pool

   ConstantPool* constants() const        { return _constants; }

   void set_constants(ConstantPool* c)    { _constants = c; }

   Method* method() const;

   // stackmap table data

   Array<u1>* stackmap_data() const { return _stackmap_data; }

   void set_stackmap_data(Array<u1>* sd) { _stackmap_data = sd; }

   bool has_stackmap_table() const { return _stackmap_data != NULL; }

   void init_fingerprint() {

     const uint64_t initval = CONST64(0x8000000000000000);

     _fingerprint = initval;

   }

   uint64_t fingerprint() const                   {

     // Since reads aren't atomic for 64 bits, if any of the high or low order

     // word is the initial value, return 0.  See init_fingerprint for initval.

     uint high_fp = (uint)(_fingerprint >> 32);

     if ((int) _fingerprint == 0 || high_fp == 0x80000000) {

       return 0L;

     } else {

       return _fingerprint;

     }

   }

   uint64_t set_fingerprint(uint64_t new_fingerprint) {

 #ifdef ASSERT

     // Assert only valid if complete/valid 64 bit _fingerprint value is read.

     uint64_t oldfp = fingerprint();

 #endif // ASSERT

     _fingerprint = new_fingerprint;

     assert(oldfp == 0L || new_fingerprint == oldfp,

            "fingerprint cannot change");

     assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0,

            "fingerprint should call init to set initial value");

     return new_fingerprint;

   }

   // name

   int name_index() const                         { return _name_index; }

   void set_name_index(int index)                 { _name_index = index; }

   // signature

   int signature_index() const                    { return _signature_index; }

   void set_signature_index(int index)            { _signature_index = index; }

   // generics support

   int generic_signature_index() const            { return _generic_signature_index; }

   void set_generic_signature_index(int index)    { _generic_signature_index = index; }

   // Sizing

   static int header_size() {

     return sizeof(ConstMethod)/HeapWordSize;

   }

   // Size needed

   static int size(int code_size, int compressed_line_number_size,

                          int local_variable_table_length,

                          int exception_table_length,

                          int checked_exceptions_length);

   int size() const                    { return _constMethod_size;}

   void set_constMethod_size(int size)     { _constMethod_size = size; }

   // code size

   int code_size() const                          { return _code_size; }

   void set_code_size(int size) {

     assert(max_method_code_size < (1 << 16),

            "u2 is too small to hold method code size in general");

     assert(0 <= size && size <= max_method_code_size, "invalid code size");

     _code_size = size;

   }

   // linenumber table - note that length is unknown until decompression,

   // see class CompressedLineNumberReadStream.

   u_char* compressed_linenumber_table() const;         // not preserved by gc

   u2* checked_exceptions_length_addr() const;

   u2* localvariable_table_length_addr() const;

   u2* exception_table_length_addr() const;

   // checked exceptions

   int checked_exceptions_length() const;

   CheckedExceptionElement* checked_exceptions_start() const;

   // localvariable table

   int localvariable_table_length() const;

   LocalVariableTableElement* localvariable_table_start() const;

   // exception table

   int exception_table_length() const;

   ExceptionTableElement* exception_table_start() const;

   // byte codes

   void    set_code(address code) {

     if (code_size() > 0) {

       memcpy(code_base(), code, code_size());

     }

   }

   address code_base() const            { return (address) (this+1); }

   address code_end() const             { return code_base() + code_size(); }

   bool    contains(address bcp) const  { return code_base() <= bcp

                                                      && bcp < code_end(); }

   // Offset to bytecodes

   static ByteSize codes_offset()

                             { return in_ByteSize(sizeof(ConstMethod)); }

   static ByteSize constants_offset()

                             { return byte_offset_of(ConstMethod, _constants); }

   // Unique id for the method

   static const u2 MAX_IDNUM;

   static const u2 UNSET_IDNUM;

   u2 method_idnum() const                        { return _method_idnum; }

   void set_method_idnum(u2 idnum)                { _method_idnum = idnum; }

   // Deallocation for RedefineClasses

   void deallocate_contents(ClassLoaderData* loader_data);

   bool is_klass() const { return false; }

   DEBUG_ONLY(bool on_stack() { return false; })

 private:

   // Since the size of the compressed line number table is unknown, the

   // offsets of the other variable sized sections are computed backwards

   // from the end of the ConstMethod*.

   // First byte after ConstMethod*

   address constMethod_end() const

                           { return (address)((oop*)this + _constMethod_size); }

   // Last short in ConstMethod*

   u2* last_u2_element() const

                                          { return (u2*)constMethod_end() - 1; }

  public:

   // Printing

   void print_on      (outputStream* st) const;

   void print_value_on(outputStream* st) const;

   const char* internal_name() const { return "{constMethod}"; }

   // Verify

   void verify_on(outputStream* st);

 };

 #endif // SHARE_VM_OOPS_CONSTMETHODOOP_HPP