/*

 * Copyright (c) 2003, 2014, 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_OOPS_CONSTMETHODOOP_HPP

#define SHARE_VM_OOPS_CONSTMETHODOOP_HPP

#include "oops/oop.hpp"

// An ConstMethod represents portions of a Java method which are not written to after

// the classfile is parsed(*see below).  This part of the method can be shared across

// processes in a read-only section with Class Data Sharing (CDS).  It's important

// that this class doesn't have virtual functions because the vptr cannot be shared

// with CDS.

//   (*)RewriteByteCodes and RewriteFrequentPairs is an exception but turned off in CDS

//

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

// structure small has a big impact on footprint.

// The actual bytecodes are inlined after the end of the ConstMethod struct.

//

// The line number table is compressed and inlined following the byte codes. It is

// found as the first byte following the byte codes.  Note that accessing the line

// number and local variable tables is not performance critical at all.

//

// The checked exceptions table and the local variable table are inlined after the

// line number table, and indexed from the end of the method. We do not compress the

// checked exceptions table since the average length is less than 2, and it is used

// by reflection so access should be fast.  We do not bother to compress the local

// variable table either since it is mostly absent.

//

//

//  ConstMethod embedded field layout (after declared fields):

//    [EMBEDDED byte codes]

//    [EMBEDDED 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!)

//    [EMBEDDED 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*)

//    [EMBEDDED 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*)

//    [EMBEDDED 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*)

//    [EMBEDDED method parameters elements + length (length last)]

//     (length is u2, elements are u2, u4 structures)

//     (see class MethodParametersElement)

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

//     (indexed from end of ConstMethod*)

//    [EMBEDDED generic signature index (u2)]

//     (indexed from end of constMethodOop)

//    [EMBEDDED annotations arrays - method, parameter, type, default]

//      pointer to Array<u1> if annotation is present

//

// IMPORTANT: If anything gets added here, there need to be changes to

// ensure that ServicabilityAgent doesn't get broken as a result!

// Utility class describing elements in checked exceptions table inlined in Method*.

class CheckedExceptionElement VALUE_OBJ_CLASS_SPEC {

 public:

  u2 class_cp_index;

};

// Utility class describing 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;

};

// Utility 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;

};

// Utility class describing elements in method parameters

class MethodParametersElement VALUE_OBJ_CLASS_SPEC {

 public:

  u2 name_cp_index;

  u2 flags;

};

class KlassSizeStats;

// Class to collect the sizes of ConstMethod inline tables

#define INLINE_TABLES_DO(do_element)            \

  do_element(localvariable_table_length)        \

  do_element(compressed_linenumber_size)        \

  do_element(exception_table_length)            \

  do_element(checked_exceptions_length)         \

  do_element(method_parameters_length)          \

  do_element(generic_signature_index)           \

  do_element(method_annotations_length)         \

  do_element(parameter_annotations_length)      \

  do_element(type_annotations_length)           \

  do_element(default_annotations_length)

#define INLINE_TABLE_DECLARE(sym)    int _##sym;

#define INLINE_TABLE_PARAM(sym)      int sym,

#define INLINE_TABLE_INIT(sym)       _##sym(sym),

#define INLINE_TABLE_NULL(sym)       _##sym(0),

#define INLINE_TABLE_ACCESSOR(sym)   int sym() const { return _##sym; }

class InlineTableSizes : StackObj {

  // declarations

  INLINE_TABLES_DO(INLINE_TABLE_DECLARE)

  int _end;

 public:

  InlineTableSizes(

      INLINE_TABLES_DO(INLINE_TABLE_PARAM)

      int end) :

      INLINE_TABLES_DO(INLINE_TABLE_INIT)

      _end(end) {}

  // Default constructor for no inlined tables

  InlineTableSizes() :

      INLINE_TABLES_DO(INLINE_TABLE_NULL)

      _end(0) {}

  // Accessors

  INLINE_TABLES_DO(INLINE_TABLE_ACCESSOR)

};

#undef INLINE_TABLE_ACCESSOR

#undef INLINE_TABLE_NULL

#undef INLINE_TABLE_INIT

#undef INLINE_TABLE_PARAM

#undef INLINE_TABLE_DECLARE

class ConstMethod : public MetaspaceObj {

  friend class VMStructs;

public:

  typedef enum { NORMAL, OVERPASS } MethodType;

private:

  enum {

    _has_linenumber_table = 0x0001,

    _has_checked_exceptions = 0x0002,

    _has_localvariable_table = 0x0004,

    _has_exception_table = 0x0008,

    _has_generic_signature = 0x0010,

    _has_method_parameters = 0x0020,

    _is_overpass = 0x0040,

    _has_method_annotations = 0x0080,

    _has_parameter_annotations = 0x0100,

    _has_type_annotations = 0x0200,

    _has_default_annotations = 0x0400

  };

  // 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;

  u2                _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                _max_stack;                  // Maximum number of entries on the expression stack

  u2                _max_locals;                 // Number of local variables used by this method

  u2                _size_of_parameters;         // size of the parameter block (receiver + arguments) in words

  // Constructor

  ConstMethod(int byte_code_size,

              InlineTableSizes* sizes,

              MethodType is_overpass,

              int size);

public:

  static ConstMethod* allocate(ClassLoaderData* loader_data,

                               int byte_code_size,

                               InlineTableSizes* sizes,

                               MethodType mt,

                               TRAPS);

  bool is_constMethod() const { return true; }

  // Inlined tables

  void set_inlined_tables_length(InlineTableSizes* sizes);

  bool has_generic_signature() const

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

  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; }

  bool has_method_parameters() const

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

  MethodType method_type() const {

    return ((_flags & _is_overpass) == 0) ? NORMAL : OVERPASS;

  }

  void set_method_type(MethodType mt) {

    if (mt == NORMAL) {

      _flags &= ~(_is_overpass);

    } else {

      _flags |= _is_overpass;

    }

  }

  // 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; }

  void copy_stackmap_data(ClassLoaderData* loader_data, u1* sd, int length, TRAPS);

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

  void init_fingerprint() {

    const uint64_t initval = UCONST64(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            {

    if (has_generic_signature()) {

      return *generic_signature_index_addr();

    } else {

      return 0;

    }

  }

  void set_generic_signature_index(u2 index)    {

    assert(has_generic_signature(), "");

    u2* addr = generic_signature_index_addr();

    *addr = index;

  }

  // Sizing

  static int header_size() {

    return sizeof(ConstMethod)/HeapWordSize;

  }

  // Size needed

  static int size(int code_size, InlineTableSizes* sizes);

  int size() const                    { return _constMethod_size;}

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

#if INCLUDE_SERVICES

  void collect_statistics(KlassSizeStats *sz) const;

#endif

  // 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* generic_signature_index_addr() const;

  u2* checked_exceptions_length_addr() const;

  u2* localvariable_table_length_addr() const;

  u2* exception_table_length_addr() const;

  u2* method_parameters_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;

  // method parameters table

  // This returns -1 if no parameters are present, a non-negative

  // value otherwise.  Note: sometimes, there are 0-length parameters

  // attributes that must be reported up to the reflection API all the

  // same.

  int method_parameters_length() const;

  MethodParametersElement* method_parameters_start() const;

  // method annotations

  bool has_method_annotations() const

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

  bool has_parameter_annotations() const

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

  bool has_type_annotations() const

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

  bool has_default_annotations() const

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

  AnnotationArray** method_annotations_addr() const;

  AnnotationArray* method_annotations() const  {

    return has_method_annotations() ? *(method_annotations_addr()) : NULL;

  }

  void set_method_annotations(AnnotationArray* anno) {

    *(method_annotations_addr()) = anno;

  }

  AnnotationArray** parameter_annotations_addr() const;

  AnnotationArray* parameter_annotations() const {

    return has_parameter_annotations() ? *(parameter_annotations_addr()) : NULL;

  }

  void set_parameter_annotations(AnnotationArray* anno) {

    *(parameter_annotations_addr()) = anno;

  }

  AnnotationArray** type_annotations_addr() const;

  AnnotationArray* type_annotations() const {

    return has_type_annotations() ? *(type_annotations_addr()) : NULL;

  }

  void set_type_annotations(AnnotationArray* anno) {

    *(type_annotations_addr()) = anno;

  }

  AnnotationArray** default_annotations_addr() const;

  AnnotationArray* default_annotations() const {

    return has_default_annotations() ? *(default_annotations_addr()) : NULL;

  }

  void set_default_annotations(AnnotationArray* anno) {

    *(default_annotations_addr()) = anno;

  }

  int method_annotations_length() const {

    return has_method_annotations() ? method_annotations()->length() : 0;

  }

  int parameter_annotations_length() const {

    return has_parameter_annotations() ? parameter_annotations()->length() : 0;

  }

  int type_annotations_length() const {

    return has_type_annotations() ? type_annotations()->length() : 0;

  }

  int default_annotations_length() const {

    return has_default_annotations() ? default_annotations()->length() : 0;

  }

  // Copy annotations from other ConstMethod

  void copy_annotations_from(ConstMethod* cm);

  // 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); }

  static ByteSize max_stack_offset()

                            { return byte_offset_of(ConstMethod, _max_stack); }

  static ByteSize size_of_locals_offset()

                            { return byte_offset_of(ConstMethod, _max_locals); }

  static ByteSize size_of_parameters_offset()

                            { return byte_offset_of(ConstMethod, _size_of_parameters); }

  // 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; }

  // max stack

  int  max_stack() const                         { return _max_stack; }

  void set_max_stack(int size)                   { _max_stack = size; }

  // max locals

  int  max_locals() const                        { return _max_locals; }

  void set_max_locals(int size)                  { _max_locals = size; }

  // size of parameters

  int  size_of_parameters() const                { return _size_of_parameters; }

  void set_size_of_parameters(int size)          { _size_of_parameters = size; }

  // 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