/*

 * Copyright (c) 1997, 2019, 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.

 *

 */

#include "classfile/vmSymbols.hpp"

#include "code/compressedStream.hpp"

#include "compiler/compilerDefinitions.hpp"

#include "compiler/oopMap.hpp"

#include "interpreter/invocationCounter.hpp"

#include "oops/annotations.hpp"

#include "oops/constantPool.hpp"

#include "oops/methodCounters.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/oop.hpp"

#include "oops/typeArrayOop.hpp"

#include "utilities/accessFlags.hpp"

#include "utilities/align.hpp"

#include "utilities/growableArray.hpp"

#include "utilities/macros.hpp"

#if INCLUDE_JFR

#include "jfr/support/jfrTraceIdExtension.hpp"

#endif

// A Method represents a Java method.

//

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

// class small has a big impact on footprint.

//

// Note that native_function and signature_handler have to be at fixed offsets

// (required by the interpreter)

//

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

//   [EMBEDDED native_function       (present only if native) ]

//   [EMBEDDED signature_handler     (present only if native) ]

class CheckedExceptionElement;

class LocalVariableTableElement;

class AdapterHandlerEntry;

class MethodData;

class MethodCounters;

class ConstMethod;

class InlineTableSizes;

class KlassSizeStats;

class CompiledMethod;

class InterpreterOopMap;

class Method : public Metadata {

 friend class VMStructs;

 friend class JVMCIVMStructs;

 private:

  // If you add a new field that points to any metaspace object, you

  // must add this field to Method::metaspace_pointers_do().

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

  MethodData*       _method_data;

  MethodCounters*   _method_counters;

  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)

  u2                _intrinsic_id;               // vmSymbols::intrinsic_id (0 == _none)

  // Flags

  enum Flags {

    _caller_sensitive      = 1 << 0,

    _force_inline          = 1 << 1,

    _dont_inline           = 1 << 2,

    _hidden                = 1 << 3,

    _has_injected_profile  = 1 << 4,

    _running_emcp          = 1 << 5,

    _intrinsic_candidate   = 1 << 6,

    _reserved_stack_access = 1 << 7

  };

  mutable u2 _flags;

  JFR_ONLY(DEFINE_TRACE_FLAG;)

#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

  // 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).

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

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

#if INCLUDE_AOT && defined(TIERED)

  CompiledMethod* _aot_code;

#endif

  // Constructor

  Method(ConstMethod* xconst, AccessFlags access_flags);

 public:

  static Method* allocate(ClassLoaderData* loader_data,

                          int byte_code_size,

                          AccessFlags access_flags,

                          InlineTableSizes* sizes,

                          ConstMethod::MethodType method_type,

                          TRAPS);

  // CDS and vtbl checking can create an empty Method to get vtbl pointer.

  Method(){}

  bool is_method() const volatile { return true; }

  void restore_unshareable_info(TRAPS);

  // accessors for instance variables

  ConstMethod* constMethod() const             { return _constMethod; }

  void set_constMethod(ConstMethod* xconst)    { _constMethod = xconst; }

  static address make_adapters(const methodHandle& mh, TRAPS);

  address from_compiled_entry() const;

  address from_compiled_entry_no_trampoline() const;

  address from_interpreted_entry() const;

  // 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           {

    return constMethod()->method_annotations();

  }

  AnnotationArray* parameter_annotations() const {

    return constMethod()->parameter_annotations();

  }

  AnnotationArray* annotation_default() const    {

    return constMethod()->default_annotations();

  }

  AnnotationArray* type_annotations() const      {

    return constMethod()->type_annotations();

  }

  // 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

#if !INCLUDE_JVMTI

  Bytecodes::Code orig_bytecode_at(int bci) const {

    ShouldNotReachHere();

    return Bytecodes::_shouldnotreachhere;

  }

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

    ShouldNotReachHere();

  };

  u2   number_of_breakpoints() const {return 0;}

#else // !INCLUDE_JVMTI

  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 {

    MethodCounters* mcs = method_counters();

    if (mcs == NULL) {

      return 0;

    } else {

      return mcs->number_of_breakpoints();

    }

  }

  void incr_number_of_breakpoints(TRAPS)         {

    MethodCounters* mcs = get_method_counters(CHECK);

    if (mcs != NULL) {

      mcs->incr_number_of_breakpoints();

    }

  }

  void decr_number_of_breakpoints(TRAPS)         {

    MethodCounters* mcs = get_method_counters(CHECK);

    if (mcs != NULL) {

      mcs->decr_number_of_breakpoints();

    }

  }

  // Initialization only

  void clear_number_of_breakpoints()             {

    MethodCounters* mcs = method_counters();

    if (mcs != NULL) {

      mcs->clear_number_of_breakpoints();

    }

  }

#endif // !INCLUDE_JVMTI

  // 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); }

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

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

  // code size

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

  // method size in words

  int method_size() const                { return sizeof(Method)/wordSize + ( is_native() ? 2 : 0 ); }

  // 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 constMethod()->max_stack(); }

  int           max_stack() const                { return constMethod()->max_stack() + extra_stack_entries(); }

  void      set_max_stack(int size)              {        constMethod()->set_max_stack(size); }

  // max locals

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

  void set_max_locals(int size)                  { constMethod()->set_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);

#if COMPILER2_OR_JVMCI

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

  void interpreter_throwout_increment(TRAPS) {

    MethodCounters* mcs = get_method_counters(CHECK);

    if (mcs != NULL) {

      mcs->interpreter_throwout_increment();

    }

  }

#endif

  int  interpreter_throwout_count() const        {

    MethodCounters* mcs = method_counters();

    if (mcs == NULL) {

      return 0;

    } else {

      return mcs->interpreter_throwout_count();

    }

  }

  // size of parameters

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

  void set_size_of_parameters(int size)          { constMethod()->set_size_of_parameters(size); }

  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.

  static int fast_exception_handler_bci_for(const methodHandle& mh, Klass* ex_klass, int throw_bci, TRAPS);

  // method data access

  MethodData* method_data() const              {

    return _method_data;

  }

  void set_method_data(MethodData* data);

  MethodCounters* method_counters() const {

    return _method_counters;

  }

  void clear_method_counters() {

    _method_counters = NULL;

  }

  bool init_method_counters(MethodCounters* counters);

#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                   {

    if (method_counters() == NULL) {

      return 0;

    } else {

      return method_counters()->interpreter_invocation_count();

    }

  }

  void set_prev_event_count(int count) {

    MethodCounters* mcs = method_counters();

    if (mcs != NULL) {

      mcs->set_interpreter_invocation_count(count);

    }

  }

  jlong prev_time() const                        {

    MethodCounters* mcs = method_counters();

    return mcs == NULL ? 0 : mcs->prev_time();

  }

  void set_prev_time(jlong time) {

    MethodCounters* mcs = method_counters();

    if (mcs != NULL) {

      mcs->set_prev_time(time);

    }

  }

  float rate() const                             {

    MethodCounters* mcs = method_counters();

    return mcs == NULL ? 0 : mcs->rate();

  }

  void set_rate(float rate) {

    MethodCounters* mcs = method_counters();

    if (mcs != NULL) {

      mcs->set_rate(rate);

    }

  }

#if INCLUDE_AOT

  void set_aot_code(CompiledMethod* aot_code) {

    _aot_code = aot_code;

  }

  CompiledMethod* aot_code() const {

    return _aot_code;

  }

#else

  CompiledMethod* aot_code() const { return NULL; }

#endif // INCLUDE_AOT

#endif // TIERED

  int nmethod_age() const {

    if (method_counters() == NULL) {

      return INT_MAX;

    } else {

      return method_counters()->nmethod_age();

    }

  }

  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(const methodHandle& method, TRAPS);

  static MethodCounters* build_method_counters(Method* m, TRAPS);

  int interpreter_invocation_count() {

    if (TieredCompilation) {

      return invocation_count();

    } else {

      MethodCounters* mcs = method_counters();

      return (mcs == NULL) ? 0 : mcs->interpreter_invocation_count();

    }

  }

#if COMPILER2_OR_JVMCI

  int increment_interpreter_invocation_count(TRAPS) {

    if (TieredCompilation) ShouldNotReachHere();

    MethodCounters* mcs = get_method_counters(CHECK_0);

    return (mcs == NULL) ? 0 : mcs->increment_interpreter_invocation_count();

  }

#endif

#ifndef PRODUCT

  int  compiled_invocation_count() const         { return _compiled_invocation_count;  }

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

#else

  // for PrintMethodData in a product build

  int  compiled_invocation_count() const         { return 0;  }

#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

  CompiledMethod* volatile code() const;

  void clear_code(bool acquire_lock = true);    // Clear out any compiled code

  static void set_code(const methodHandle& mh, CompiledMethod* code);

  void set_adapter_entry(AdapterHandlerEntry* adapter) {

    constMethod()->set_adapter_entry(adapter);

  }

  void update_adapter_trampoline(AdapterHandlerEntry* adapter) {

    constMethod()->update_adapter_trampoline(adapter);

  }

  address get_i2c_entry();

  address get_c2i_entry();

  address get_c2i_unverified_entry();

  AdapterHandlerEntry* adapter() const {

    return constMethod()->adapter();

  }

  // setup entry points

  void link_method(const methodHandle& method, TRAPS);

  // clear entry points. Used by sharing code during dump time

  void unlink_method() NOT_CDS_RETURN;

  virtual void metaspace_pointers_do(MetaspaceClosure* iter);

  virtual MetaspaceObj::Type type() const { return MethodType; }

  // vtable index

  enum VtableIndexFlag {

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

    // These few negative values are used as sentinels.

    itable_index_max        = -10, // first itable index, growing downward

    pending_itable_index    = -9,  // itable index will be assigned

    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; })

  bool has_vtable_index() const                  { return _vtable_index >= 0; }

  int  vtable_index() const                      { return _vtable_index; }

  void set_vtable_index(int index);

  DEBUG_ONLY(bool valid_itable_index() const     { return _vtable_index <= pending_itable_index; })