/*

 * Copyright (c) 1997, 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.

 *

 */

#ifndef SHARE_VM_OOPS_METHODOOP_HPP

#define SHARE_VM_OOPS_METHODOOP_HPP

#include "classfile/vmSymbols.hpp"

#include "code/compressedStream.hpp"

#include "compiler/oopMap.hpp"

#include "interpreter/invocationCounter.hpp"

#include "oops/annotations.hpp"

#include "oops/constMethod.hpp"

#include "oops/constantPool.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/oop.hpp"

#include "oops/typeArrayOop.hpp"

#include "utilities/accessFlags.hpp"

#include "utilities/growableArray.hpp"

// A Method* 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 Method 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                                                |

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

// | ConstMethod*                   (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|   flags    |  throwout_count            |

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

// | num_breakpoints         |  (unused)                  |

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

// | invocation_counter                                   |

// | backedge_counter                                     |

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

// |           prev_time (tiered only, 64 bit wide)       |

// |                                                      |

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

// |                  rate (tiered)                       |

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

// | 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 MethodData;

class Method : public Metadata {

 friend class VMStructs;

 private:

  ConstMethod*      _constMethod;                // Method read-only data.

  MethodData*       _method_data;

  int               _interpreter_invocation_count; // Count of times invoked (reused as prev_event_count in tiered)

  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                _jfr_towrite  : 1,           // Flags

                    _force_inline : 1,

                    _hidden       : 1,

                    _dont_inline  : 1,

                                  : 4;

  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

#ifdef TIERED

  jlong             _prev_time;                   // Previous time the rate was acquired

  float             _rate;                        // Events (invocation and backedge counter increments) per millisecond

#endif

#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 Method*. 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

  // Constructor

  Method(ConstMethod* xconst, AccessFlags access_flags, int size);

 public:

  static Method* allocate(ClassLoaderData* loader_data,

                            int byte_code_size,

                            AccessFlags access_flags,

                            int compressed_line_number_size,

                            int localvariable_table_length,

                            int exception_table_length,

                            int checked_exceptions_length,

                            TRAPS);

  Method() { assert(DumpSharedSpaces || UseSharedSpaces, "only for CDS"); }

  // The Method vtable is restored by this call when the Method is in the

  // shared archive.  See patch_klass_vtables() in metaspaceShared.cpp for

  // all the gory details.  SA, dtrace and pstack helpers distinguish metadata

  // by their vtable.

  void restore_vtable() { guarantee(is_method(), "vtable restored by this call"); }

  bool is_method() const volatile { return true; }

  // accessors for instance variables

  ConstMethod* constMethod() const             { return _constMethod; }

  void set_constMethod(ConstMethod* xconst)    { _constMethod = 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

  Symbol* 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

  Symbol* 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

  Symbol* generic_signature() const              { int idx = generic_signature_index(); return ((idx != 0) ? constants()->symbol_at(idx) : (Symbol*)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

  AnnotationArray* annotations() const           {

    InstanceKlass* ik = InstanceKlass::cast(method_holder());

    if (ik->annotations() == NULL) {

      return NULL;

    }

    return ik->annotations()->get_method_annotations_of(method_idnum());

  }

  AnnotationArray* parameter_annotations() const {

    InstanceKlass* ik = InstanceKlass::cast(method_holder());

    if (ik->annotations() == NULL) {

      return NULL;

    }

    return ik->annotations()->get_method_parameter_annotations_of(method_idnum());

  }

  AnnotationArray* annotation_default() const    {

    InstanceKlass* ik = InstanceKlass::cast(method_holder());

    if (ik->annotations() == NULL) {

      return NULL;

    }

    return ik->annotations()->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() const;

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

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

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

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

  Bytecodes::Code java_code_at(int bci) const {

    return Bytecodes::java_code_at(this, bcp_from(bci));

  }

  Bytecodes::Code code_at(int bci) const {

    return Bytecodes::code_at(this, bcp_from(bci));

  }

  // JVMTI breakpoints

  Bytecodes::Code orig_bytecode_at(int bci) const;

  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

  // note: also used by jfr

  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 Klass* holding this method

  ConstantPool* constants() const              { return constMethod()->constants(); }

  void set_constants(ConstantPool* c)          { constMethod()->set_constants(c); }

  // max stack

  // return original max stack size for method verification

  int  verifier_max_stack() const                { return _max_stack; }

  int           max_stack() const                { return _max_stack + extra_stack_entries(); }

  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_comp_level() const;

  void set_highest_comp_level(int level);

  int highest_osr_comp_level() const;

  void set_highest_osr_comp_level(int 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();

  }

  Array<u1>* stackmap_data() const {

    return constMethod()->stackmap_data();

  }

  void set_stackmap_data(Array<u1>* sd) {

    constMethod()->set_stackmap_data(sd);

  }

  // exception handler table

  bool has_exception_handler() const

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

  int exception_table_length() const

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

  ExceptionTableElement* exception_table_start() const

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

  // 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

  MethodData* method_data() const              {

    return _method_data;

  }

  void set_method_data(MethodData* data)       {

    _method_data = data;

  }

  // invocation counter

  InvocationCounter* invocation_counter() { return &_invocation_counter; }

  InvocationCounter* backedge_counter()   { return &_backedge_counter; }

#ifdef TIERED

  // We are reusing interpreter_invocation_count as a holder for the previous event count!

  // We can do that since interpreter_invocation_count is not used in tiered.

  int prev_event_count() const                   { return _interpreter_invocation_count;  }

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

  jlong prev_time() const                        { return _prev_time; }

  void set_prev_time(jlong time)                 { _prev_time = time; }

  float rate() const                             { return _rate; }

  void set_rate(float rate)                      { _rate = rate; }

#endif

  int invocation_count();

  int backedge_count();

  bool was_executed_more_than(int n);

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

  static void build_interpreter_method_data(methodHandle method, TRAPS);

  int interpreter_invocation_count() {

    if (TieredCompilation) return invocation_count();

    else return _interpreter_invocation_count;

  }

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

  int increment_interpreter_invocation_count() {

    if (TieredCompilation) ShouldNotReachHere();

    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