/*

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

// A methodOop represents a Java method.

//

// 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.

//

// We put all oops and method_size first for better gc cache locality.

//

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

//

// There are bits in the access_flags telling whether inlined tables are present.

// Note that accessing the line number and local variable tables is not performance critical at all.

// Accessing the checked exceptions table is used by reflection, so we put that last to make access

// to it fast.

//

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

// byte following the byte codes. 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 do not bother to compress the local

// variable table either since it is mostly absent.

//

// Note that native_function and signature_handler has to be at fixed offsets (required by the interpreter)

//

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

// | header                                               |

// | klass                                                |

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

// | constMethodOop                 (oop)                 |

// | constants                      (oop)                 |

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

// | methodData                     (oop)                 |

// | interp_invocation_count                              |

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

// | access_flags                                         |

// | vtable_index                                         |

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

// | result_index (C++ interpreter only)                  |

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

// | method_size             | max_stack                  |

// | max_locals              | size_of_parameters         |

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

// | intrinsic_id, highest_tier  |       (unused)         |

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

// | throwout_count          | num_breakpoints            |

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

// | invocation_counter                                   |

// | backedge_counter                                     |

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

// | code                           (pointer)             |

// | i2i                            (pointer)             |

// | adapter                        (pointer)             |

// | from_compiled_entry            (pointer)             |

// | from_interpreted_entry         (pointer)             |

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

// | native_function       (present only if native)       |

// | signature_handler     (present only if native)       |

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

class CheckedExceptionElement;

class LocalVariableTableElement;

class AdapterHandlerEntry;

class methodDataOopDesc;

class methodOopDesc : public oopDesc {

 friend class methodKlass;

 friend class VMStructs;

 private:

  constMethodOop    _constMethod;                // Method read-only data.

  constantPoolOop   _constants;                  // Constant pool

  methodDataOop     _method_data;

  int               _interpreter_invocation_count; // Count of times invoked

  AccessFlags       _access_flags;               // Access flags

  int               _vtable_index;               // vtable index of this method (see VtableIndexFlag)

                                                 // note: can have vtables with >2**16 elements (because of inheritance)

#ifdef CC_INTERP

  int               _result_index;               // C++ interpreter needs for converting results to/from stack

#endif

  u2                _method_size;                // size of this object

  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

  u1                _intrinsic_id;               // vmSymbols::intrinsic_id (0 == _none)

  u1                _highest_tier_compile;       // Highest compile level this method has ever seen.

  u2                _interpreter_throwout_count; // Count of times method was exited via exception while interpreting

  u2                _number_of_breakpoints;      // fullspeed debugging support

  InvocationCounter _invocation_counter;         // Incremented before each activation of the method - used to trigger frequency-based optimizations

  InvocationCounter _backedge_counter;           // Incremented before each backedge taken - used to trigger frequencey-based optimizations

#ifndef PRODUCT

  int               _compiled_invocation_count;  // Number of nmethod invocations so far (for perf. debugging)

#endif

  // Entry point for calling both from and to the interpreter.

  address _i2i_entry;           // All-args-on-stack calling convention

  // Adapter blob (i2c/c2i) for this methodOop. Set once when method is linked.

  AdapterHandlerEntry* _adapter;

  // Entry point for calling from compiled code, to compiled code if it exists

  // or else the interpreter.

  volatile address _from_compiled_entry;        // Cache of: _code ? _code->entry_point() : _adapter->c2i_entry()

  // The entry point for calling both from and to compiled code is

  // "_code->entry_point()".  Because of tiered compilation and de-opt, this

  // field can come and go.  It can transition from NULL to not-null at any

  // time (whenever a compile completes).  It can transition from not-null to

  // NULL only at safepoints (because of a de-opt).

  nmethod* volatile _code;                       // Points to the corresponding piece of native code

  volatile address           _from_interpreted_entry; // Cache of _code ? _adapter->i2c_entry() : _i2i_entry

 public:

  static const bool IsUnsafeConc         = false;

  static const bool IsSafeConc           = true;

  // accessors for instance variables

  constMethodOop constMethod() const             { return _constMethod; }

  void set_constMethod(constMethodOop xconst)    { oop_store_without_check((oop*)&_constMethod, (oop)xconst); }

  static address make_adapters(methodHandle mh, TRAPS);

  volatile address from_compiled_entry() const   { return (address)OrderAccess::load_ptr_acquire(&_from_compiled_entry); }

  volatile address from_interpreted_entry() const{ return (address)OrderAccess::load_ptr_acquire(&_from_interpreted_entry); }

  // access flag

  AccessFlags access_flags() const               { return _access_flags;  }

  void set_access_flags(AccessFlags flags)       { _access_flags = flags; }

  // name

  symbolOop name() const                         { return _constants->symbol_at(name_index()); }

  int name_index() const                         { return constMethod()->name_index();         }

  void set_name_index(int index)                 { constMethod()->set_name_index(index);       }

  // signature

  symbolOop signature() const                    { return _constants->symbol_at(signature_index()); }

  int signature_index() const                    { return constMethod()->signature_index();         }

  void set_signature_index(int index)            { constMethod()->set_signature_index(index);       }

  // generics support

  symbolOop generic_signature() const            { int idx = generic_signature_index(); return ((idx != 0) ? _constants->symbol_at(idx) : (symbolOop)NULL); }

  int generic_signature_index() const            { return constMethod()->generic_signature_index(); }

  void set_generic_signature_index(int index)    { constMethod()->set_generic_signature_index(index); }

  // annotations support

  typeArrayOop annotations() const               { return instanceKlass::cast(method_holder())->get_method_annotations_of(method_idnum()); }

  typeArrayOop parameter_annotations() const     { return instanceKlass::cast(method_holder())->get_method_parameter_annotations_of(method_idnum()); }

  typeArrayOop annotation_default() const        { return instanceKlass::cast(method_holder())->get_method_default_annotations_of(method_idnum()); }

#ifdef CC_INTERP

  void set_result_index(BasicType type);

  int  result_index()                            { return _result_index; }

#endif

  // Helper routine: get klass name + "." + method name + signature as

  // C string, for the purpose of providing more useful NoSuchMethodErrors

  // and fatal error handling. The string is allocated in resource

  // area if a buffer is not provided by the caller.

  char* name_and_sig_as_C_string();

  char* name_and_sig_as_C_string(char* buf, int size);

  // Static routine in the situations we don't have a methodOop

  static char* name_and_sig_as_C_string(Klass* klass, symbolOop method_name, symbolOop signature);

  static char* name_and_sig_as_C_string(Klass* klass, symbolOop method_name, symbolOop signature, char* buf, int size);

  // JVMTI breakpoints

  Bytecodes::Code orig_bytecode_at(int bci);

  void        set_orig_bytecode_at(int bci, Bytecodes::Code code);

  void set_breakpoint(int bci);

  void clear_breakpoint(int bci);

  void clear_all_breakpoints();

  // Tracking number of breakpoints, for fullspeed debugging.

  // Only mutated by VM thread.

  u2   number_of_breakpoints() const             { return _number_of_breakpoints; }

  void incr_number_of_breakpoints()              { ++_number_of_breakpoints; }

  void decr_number_of_breakpoints()              { --_number_of_breakpoints; }

  // Initialization only

  void clear_number_of_breakpoints()             { _number_of_breakpoints = 0; }

  // index into instanceKlass methods() array

  u2 method_idnum() const           { return constMethod()->method_idnum(); }

  void set_method_idnum(u2 idnum)   { constMethod()->set_method_idnum(idnum); }

  // code size

  int code_size() const                  { return constMethod()->code_size(); }

  // method size

  int method_size() const                        { return _method_size; }

  void set_method_size(int size) {

    assert(0 <= size && size < (1 << 16), "invalid method size");

    _method_size = size;

  }

  // constant pool for klassOop holding this method

  constantPoolOop constants() const              { return _constants; }

  void set_constants(constantPoolOop c)          { oop_store_without_check((oop*)&_constants, c); }

  // 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; }

  int highest_tier_compile()                     { return _highest_tier_compile;}

  void set_highest_tier_compile(int level)      { _highest_tier_compile = level;}

  // Count of times method was exited via exception while interpreting

  void interpreter_throwout_increment() {

    if (_interpreter_throwout_count < 65534) {

      _interpreter_throwout_count++;

    }

  }

  int  interpreter_throwout_count() const        { return _interpreter_throwout_count; }

  void set_interpreter_throwout_count(int count) { _interpreter_throwout_count = count; }

  // size of parameters

  int  size_of_parameters() const                { return _size_of_parameters; }

  bool has_stackmap_table() const {

    return constMethod()->has_stackmap_table();

  }

  typeArrayOop stackmap_data() const {

    return constMethod()->stackmap_data();

  }

  // exception handler table

  typeArrayOop exception_table() const

                                   { return constMethod()->exception_table(); }

  void set_exception_table(typeArrayOop e)

                                     { constMethod()->set_exception_table(e); }

  bool has_exception_handler() const

                             { return constMethod()->has_exception_handler(); }

  // Finds the first entry point bci of an exception handler for an

  // exception of klass ex_klass thrown at throw_bci. A value of NULL

  // for ex_klass indicates that the exception klass is not known; in

  // this case it matches any constraint class. Returns -1 if the

  // exception cannot be handled in this method. The handler

  // constraint classes are loaded if necessary. Note that this may

  // throw an exception if loading of the constraint classes causes

  // an IllegalAccessError (bugid 4307310) or an OutOfMemoryError.

  // If an exception is thrown, returns the bci of the

  // exception handler which caused the exception to be thrown, which

  // is needed for proper retries. See, for example,

  // InterpreterRuntime::exception_handler_for_exception.

  int fast_exception_handler_bci_for(KlassHandle ex_klass, int throw_bci, TRAPS);

  // method data access

  methodDataOop method_data() const              {

    return _method_data;

  }

  void set_method_data(methodDataOop data)       {

    oop_store_without_check((oop*)&_method_data, (oop)data);

  }

  // invocation counter

  InvocationCounter* invocation_counter()        { return &_invocation_counter; }

  InvocationCounter* backedge_counter()          { return &_backedge_counter; }

  int invocation_count() const                   { return _invocation_counter.count(); }

  int backedge_count() const                     { return _backedge_counter.count(); }

  bool was_executed_more_than(int n) const;

  bool was_never_executed() const                { return !was_executed_more_than(0); }

  static void build_interpreter_method_data(methodHandle method, TRAPS);

  int interpreter_invocation_count() const       { return _interpreter_invocation_count; }

  void set_interpreter_invocation_count(int count) { _interpreter_invocation_count = count; }

  int increment_interpreter_invocation_count() { return ++_interpreter_invocation_count; }

#ifndef PRODUCT

  int  compiled_invocation_count() const         { return _compiled_invocation_count; }

  void set_compiled_invocation_count(int count)  { _compiled_invocation_count = count; }

#endif // not PRODUCT

  // Clear (non-shared space) pointers which could not be relevant

  // if this (shared) method were mapped into another JVM.

  void remove_unshareable_info();

  // nmethod/verified compiler entry

  address verified_code_entry();

  bool check_code() const;      // Not inline to avoid circular ref

  nmethod* volatile code() const                 { assert( check_code(), "" ); return (nmethod *)OrderAccess::load_ptr_acquire(&_code); }

  void clear_code();            // Clear out any compiled code

  void set_code(methodHandle mh, nmethod* code);

  void set_adapter_entry(AdapterHandlerEntry* adapter) {  _adapter = adapter; }

  address get_i2c_entry();

  address get_c2i_entry();

  address get_c2i_unverified_entry();

  AdapterHandlerEntry* adapter() {  return _adapter; }

  // setup entry points

  void link_method(methodHandle method, TRAPS);

  // clear entry points. Used by sharing code

  void unlink_method();

  // vtable index

  enum VtableIndexFlag {

    // Valid vtable indexes are non-negative (>= 0).

    // These few negative values are used as sentinels.

    highest_unused_vtable_index_value = -5,

    invalid_vtable_index    = -4,  // distinct from any valid vtable index

    garbage_vtable_index    = -3,  // not yet linked; no vtable layout yet

    nonvirtual_vtable_index = -2   // there is no need for vtable dispatch

    // 6330203 Note:  Do not use -1, which was overloaded with many meanings.

  };

  DEBUG_ONLY(bool valid_vtable_index() const     { return _vtable_index >= nonvirtual_vtable_index; })

  int  vtable_index() const                      { assert(valid_vtable_index(), "");

                                                   return _vtable_index; }

  void set_vtable_index(int index)               { _vtable_index = index; }

  // interpreter entry

  address interpreter_entry() const              { return _i2i_entry; }

  // Only used when first initialize so we can set _i2i_entry and _from_interpreted_entry

  void set_interpreter_entry(address entry)      { _i2i_entry = entry;  _from_interpreted_entry = entry; }

  int  interpreter_kind(void) {

     return constMethod()->interpreter_kind();

  }

  void set_interpreter_kind();

  void set_interpreter_kind(int kind) {

    constMethod()->set_interpreter_kind(kind);

  }

  // native function (used for native methods only)

  enum {

    native_bind_event_is_interesting = true

  };

  address native_function() const                { return *(native_function_addr()); }

  // Must specify a real function (not NULL).

  // Use clear_native_function() to unregister.

  void set_native_function(address function, bool post_event_flag);

  bool has_native_function() const;

  void clear_native_function();

  // signature handler (used for native methods only)

  address signature_handler() const              { return *(signature_handler_addr()); }

  void set_signature_handler(address handler);

  // Interpreter oopmap support

  void mask_for(int bci, InterpreterOopMap* mask);

#ifndef PRODUCT

  // operations on invocation counter

  void print_invocation_count() const;

#endif

  // byte codes

  void    set_code(address code)      { return constMethod()->set_code(code); }

  address code_base() const           { return constMethod()->code_base(); }

  bool    contains(address bcp) const { return constMethod()->contains(bcp); }

  // prints byte codes

  void print_codes() const            { print_codes_on(tty); }

  void print_codes_on(outputStream* st) const                      PRODUCT_RETURN;

  void print_codes_on(int from, int to, outputStream* st) const    PRODUCT_RETURN;

  // checked exceptions

  int checked_exceptions_length() const

                         { return constMethod()->checked_exceptions_length(); }

  CheckedExceptionElement* checked_exceptions_start() const

                          { return constMethod()->checked_exceptions_start(); }

  // localvariable table

  bool has_localvariable_table() const

                          { return constMethod()->has_localvariable_table(); }

  int localvariable_table_length() const

                        { return constMethod()->localvariable_table_length(); }

  LocalVariableTableElement* localvariable_table_start() const

                         { return constMethod()->localvariable_table_start(); }

  bool has_linenumber_table() const

                              { return constMethod()->has_linenumber_table(); }

  u_char* compressed_linenumber_table() const

                       { return constMethod()->compressed_linenumber_table(); }

  // method holder (the klassOop holding this method)

  klassOop method_holder() const                 { return _constants->pool_holder(); }

  void compute_size_of_parameters(Thread *thread); // word size of parameters (receiver if any + arguments)

  symbolOop klass_name() const;                  // returns the name of the method holder

  BasicType result_type() const;                 // type of the method result

  int result_type_index() const;                 // type index of the method result

  bool is_returning_oop() const                  { BasicType r = result_type(); return (r == T_OBJECT || r == T_ARRAY); }

  bool is_returning_fp() const                   { BasicType r = result_type(); return (r == T_FLOAT || r == T_DOUBLE); }

  // Checked exceptions thrown by this method (resolved to mirrors)

  objArrayHandle resolved_checked_exceptions(TRAPS) { return resolved_checked_exceptions_impl(this, THREAD); }

  // Access flags

  bool is_public() const                         { return access_flags().is_public();      }

  bool is_private() const                        { return access_flags().is_private();     }

  bool is_protected() const                      { return access_flags().is_protected();   }

  bool is_package_private() const                { return !is_public() && !is_private() && !is_protected(); }

  bool is_static() const                         { return access_flags().is_static();      }

  bool is_final() const                          { return access_flags().is_final();       }

  bool is_synchronized() const                   { return access_flags().is_synchronized();}

  bool is_native() const                         { return access_flags().is_native();      }

  bool is_abstract() const                       { return access_flags().is_abstract();    }

  bool is_strict() const                         { return access_flags().is_strict();      }

  bool is_synthetic() const                      { return access_flags().is_synthetic();   }

  // returns true if contains only return operation

  bool is_empty_method() const;

  // returns true if this is a vanilla constructor

  bool is_vanilla_constructor() const;

  // checks method and its method holder

  bool is_final_method() const;

  bool is_strict_method() const;

  // true if method needs no dynamic dispatch (final and/or no vtable entry)

  bool can_be_statically_bound() const;

  // returns true if the method has any backward branches.

  bool has_loops() {

    return access_flags().loops_flag_init() ? access_flags().has_loops() : compute_has_loops_flag();

  };

  bool compute_has_loops_flag();

  bool has_jsrs() {

    return access_flags().has_jsrs();

  };

  void set_has_jsrs() {

    _access_flags.set_has_jsrs();

  }

  // returns true if the method has any monitors.

  bool has_monitors() const                      { return is_synchronized() || access_flags().has_monitor_bytecodes(); }

  bool has_monitor_bytecodes() const             { return access_flags().has_monitor_bytecodes(); }

  void set_has_monitor_bytecodes()               { _access_flags.set_has_monitor_bytecodes(); }

  // monitor matching. This returns a conservative estimate of whether the monitorenter/monitorexit bytecodes

  // propererly nest in the method. It might return false, even though they actually nest properly, since the info.

  // has not been computed yet.

  bool guaranteed_monitor_matching() const       { return access_flags().is_monitor_matching(); }

  void set_guaranteed_monitor_matching()         { _access_flags.set_monitor_matching(); }

  // returns true if the method is an accessor function (setter/getter).

  bool is_accessor() const;

  // returns true if the method is an initializer (<init> or <clinit>).

  bool is_initializer() const;

  // compiled code support

  // NOTE: code() is inherently racy as deopt can be clearing code

  // simultaneously. Use with caution.

  bool has_compiled_code() const                 { return code() != NULL; }

  // sizing

  static int object_size(bool is_native);

  static int header_size()                       { return sizeof(methodOopDesc)/HeapWordSize; }

  int object_size() const                        { return method_size(); }

  bool object_is_parsable() const                { return method_size() > 0; }

  // interpreter support

  static ByteSize const_offset()                 { return byte_offset_of(methodOopDesc, _constMethod       ); }

  static ByteSize constants_offset()             { return byte_offset_of(methodOopDesc, _constants         ); }

  static ByteSize access_flags_offset()          { return byte_offset_of(methodOopDesc, _access_flags      ); }

#ifdef CC_INTERP

  static ByteSize result_index_offset()          { return byte_offset_of(methodOopDesc, _result_index ); }

#endif /* CC_INTERP */

  static ByteSize size_of_locals_offset()        { return byte_offset_of(methodOopDesc, _max_locals        ); }

  static ByteSize size_of_parameters_offset()    { return byte_offset_of(methodOopDesc, _size_of_parameters); }

  static ByteSize from_compiled_offset()         { return byte_offset_of(methodOopDesc, _from_compiled_entry); }

  static ByteSize code_offset()                  { return byte_offset_of(methodOopDesc, _code); }

  static ByteSize invocation_counter_offset()    { return byte_offset_of(methodOopDesc, _invocation_counter); }

  static ByteSize backedge_counter_offset()      { return byte_offset_of(methodOopDesc, _backedge_counter); }

  static ByteSize method_data_offset()           {

    return byte_offset_of(methodOopDesc, _method_data);

  }

  static ByteSize interpreter_invocation_counter_offset() { return byte_offset_of(methodOopDesc, _interpreter_invocation_count); }

#ifndef PRODUCT

  static ByteSize compiled_invocation_counter_offset() { return byte_offset_of(methodOopDesc, _compiled_invocation_count); }

#endif // not PRODUCT

  static ByteSize native_function_offset()       { return in_ByteSize(sizeof(methodOopDesc));                 }

  static ByteSize from_interpreted_offset()      { return byte_offset_of(methodOopDesc, _from_interpreted_entry ); }

  static ByteSize interpreter_entry_offset()     { return byte_offset_of(methodOopDesc, _i2i_entry ); }

  static ByteSize signature_handler_offset()     { return in_ByteSize(sizeof(methodOopDesc) + wordSize);      }

  static ByteSize max_stack_offset()             { return byte_offset_of(methodOopDesc, _max_stack         ); }

  // for code generation

  static int method_data_offset_in_bytes()       { return offset_of(methodOopDesc, _method_data); }

  static int interpreter_invocation_counter_offset_in_bytes()

                                                 { return offset_of(methodOopDesc, _interpreter_invocation_count); }

  // Static methods that are used to implement member methods where an exposed this pointer

  // is needed due to possible GCs

  static objArrayHandle resolved_checked_exceptions_impl(methodOop this_oop, TRAPS);

  // Returns the byte code index from the byte code pointer

  int     bci_from(address bcp) const;

  address bcp_from(int     bci) const;

  int validate_bci_from_bcx(intptr_t bcx) const;

  // Returns the line number for a bci if debugging information for the method is prowided,

  // -1 is returned otherwise.

  int line_number_from_bci(int bci) const;

  // Reflection support

  bool is_overridden_in(klassOop k) const;

  // JSR 292 support

  bool is_method_handle_invoke() const              { return access_flags().is_method_handle_invoke(); }