/*

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 * 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

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 */

#ifndef SHARE_VM_OOPS_KLASSVTABLE_HPP

#define SHARE_VM_OOPS_KLASSVTABLE_HPP

#include "memory/allocation.hpp"

#include "oops/oopsHierarchy.hpp"

#include "runtime/handles.hpp"

#include "utilities/growableArray.hpp"

// A klassVtable abstracts the variable-length vtable that is embedded in InstanceKlass

// and ArrayKlass.  klassVtable objects are used just as convenient transient accessors to the vtable,

// not to actually hold the vtable data.

// Note: the klassVtable should not be accessed before the class has been verified

// (until that point, the vtable is uninitialized).

// Currently a klassVtable contains a direct reference to the vtable data, and is therefore

// not preserved across GCs.

class vtableEntry;

class klassVtable : public ResourceObj {

  KlassHandle  _klass;            // my klass

  int          _tableOffset;      // offset of start of vtable data within klass

  int          _length;           // length of vtable (number of entries)

#ifndef PRODUCT

  int          _verify_count;     // to make verify faster

#endif

  // Ordering important, so greater_than (>) can be used as an merge operator.

  enum AccessType {

    acc_private         = 0,

    acc_package_private = 1,

    acc_publicprotected = 2

  };

 public:

  klassVtable(KlassHandle h_klass, void* base, int length) : _klass(h_klass) {

    _tableOffset = (address)base - (address)h_klass(); _length = length;

  }

  // accessors

  vtableEntry* table() const      { return (vtableEntry*)(address(_klass()) + _tableOffset); }

  KlassHandle klass() const       { return _klass;  }

  int length() const              { return _length; }

  inline Method* method_at(int i) const;

  inline Method* unchecked_method_at(int i) const;

  inline Method** adr_method_at(int i) const;

  // searching; all methods return -1 if not found

  int index_of(Method* m) const                         { return index_of(m, _length); }

  int index_of_miranda(Symbol* name, Symbol* signature);

  void initialize_vtable(bool checkconstraints, TRAPS);   // initialize vtable of a new klass

  // CDS/RedefineClasses support - clear vtables so they can be reinitialized

  // at dump time.  Clearing gives us an easy way to tell if the vtable has

  // already been reinitialized at dump time (see dump.cpp).  Vtables can

  // be initialized at run time by RedefineClasses so dumping the right order

  // is necessary.

  void clear_vtable();

  bool is_initialized();

  // computes vtable length (in words) and the number of miranda methods

  // RedefineClasses() API support:

  // If any entry of this vtable points to any of old_methods,

  // replace it with the corresponding new_method.

  // trace_name_printed is set to true if the current call has

  // printed the klass name so that other routines in the adjust_*

  // group don't print the klass name.

  void adjust_method_entries(Method** old_methods, Method** new_methods,

                             int methods_length, bool * trace_name_printed);

  // Debugging code

  void print()                                              PRODUCT_RETURN;

  void verify(outputStream* st, bool force = false);

  static void print_statistics()                            PRODUCT_RETURN;

#ifndef PRODUCT

  bool check_no_old_entries();

  void dump_vtable();

#endif

 protected:

  friend class vtableEntry;

 private:

  enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;

  void copy_vtable_to(vtableEntry* start);

  int  initialize_from_super(KlassHandle super);

  int  index_of(Method* m, int len) const; // same as index_of, but search only up to len

  void put_method_at(Method* m, int index);

  static bool needs_new_vtable_entry(methodHandle m, Klass* super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);

  bool update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS);

 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method, int vtable_index,

                                         Handle target_loader, Symbol* target_classname, Thread* THREAD);

  // support for miranda methods

  bool is_miranda_entry_at(int i);

  static bool is_miranda(Method* m, Array<Method*>* class_methods, Klass* super);

  void verify_against(outputStream* st, klassVtable* vt, int index);

  inline InstanceKlass* ik() const;

};

// private helper class for klassVtable

// description of entry points:

//    destination is interpreted:

//      from_compiled_code_entry_point -> c2iadapter

//      from_interpreter_entry_point   -> interpreter entry point

//    destination is compiled:

//      from_compiled_code_entry_point -> nmethod entry point

//      from_interpreter_entry_point   -> i2cadapter

class vtableEntry VALUE_OBJ_CLASS_SPEC {

 public:

  // size in words

  static int size() {

    return sizeof(vtableEntry) / sizeof(HeapWord);

  }

  static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }

  Method* method() const    { return _method; }

 private:

  Method* _method;

  void set(Method* method)  { assert(method != NULL, "use clear"); _method = method; }

  void clear()                { _method = NULL; }

  void print()                                        PRODUCT_RETURN;

  void verify(klassVtable* vt, outputStream* st);

  friend class klassVtable;

};

inline Method* klassVtable::method_at(int i) const {

  assert(i >= 0 && i < _length, "index out of bounds");

  assert(table()[i].method() != NULL, "should not be null");

  assert(((Metadata*)table()[i].method())->is_method(), "should be method");

  return table()[i].method();

}

inline Method* klassVtable::unchecked_method_at(int i) const {

  assert(i >= 0 && i < _length, "index out of bounds");

  return table()[i].method();

}

inline Method** klassVtable::adr_method_at(int i) const {

  // Allow one past the last entry to be referenced; useful for loop bounds.

  assert(i >= 0 && i <= _length, "index out of bounds");

  return (Method**)(address(table() + i) + vtableEntry::method_offset_in_bytes());

}

// --------------------------------------------------------------------------------

class klassItable;

class itableMethodEntry;

class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {

 private:

  Klass* _interface;

  int      _offset;

 public:

  Klass* interface_klass() const { return _interface; }

  int      offset() const          { return _offset; }

  static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }

  itableMethodEntry* first_method_entry(Klass* k)              { return method_entry(k, _offset); }

  void initialize(Klass* interf, int offset) { _interface = interf; _offset = offset; }

  // Static size and offset accessors

  static int size()                       { return sizeof(itableOffsetEntry) / HeapWordSize; }    // size in words

  static int interface_offset_in_bytes()  { return offset_of(itableOffsetEntry, _interface); }

  static int offset_offset_in_bytes()     { return offset_of(itableOffsetEntry, _offset); }

  friend class klassItable;

};

class itableMethodEntry VALUE_OBJ_CLASS_SPEC {

 private:

  Method* _method;

 public:

  Method* method() const { return _method; }

  void clear()             { _method = NULL; }

  void initialize(Method* method);

  // Static size and offset accessors

  static int size()                         { return sizeof(itableMethodEntry) / HeapWordSize; }  // size in words

  static int method_offset_in_bytes()       { return offset_of(itableMethodEntry, _method); }

  friend class klassItable;

};

//

// Format of an itable

//

//    ---- offset table ---

//    Klass* of interface 1             \

//    offset to vtable from start of oop  / offset table entry

//    ...

//    Klass* of interface n             \

//    offset to vtable from start of oop  / offset table entry

//    --- vtable for interface 1 ---

//    Method*                             \

//    compiler entry point                / method table entry

//    ...

//    Method*                             \

//    compiler entry point                / method table entry

//    -- vtable for interface 2 ---

//    ...

//

class klassItable : public ResourceObj {

 private:

  instanceKlassHandle  _klass;             // my klass

  int                  _table_offset;      // offset of start of itable data within klass (in words)

  int                  _size_offset_table; // size of offset table (in itableOffset entries)

  int                  _size_method_table; // size of methodtable (in itableMethodEntry entries)

  void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);

 public:

  klassItable(instanceKlassHandle klass);

  itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");

                                           return &((itableOffsetEntry*)vtable_start())[i]; }

  itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");

                                           return &((itableMethodEntry*)method_start())[i]; }

  int size_offset_table()                { return _size_offset_table; }

  // Initialization

  void initialize_itable(bool checkconstraints, TRAPS);

  // Updates

  void initialize_with_method(Method* m);

  // RedefineClasses() API support:

  // if any entry of this itable points to any of old_methods,

  // replace it with the corresponding new_method.

  // trace_name_printed is set to true if the current call has

  // printed the klass name so that other routines in the adjust_*

  // group don't print the klass name.

  void adjust_method_entries(Method** old_methods, Method** new_methods,

                             int methods_length, bool * trace_name_printed);

  // Setup of itable

  static int compute_itable_size(Array<Klass*>* transitive_interfaces);

  static void setup_itable_offset_table(instanceKlassHandle klass);

  // Resolving of method to index

  static int compute_itable_index(Method* m);

  // ...and back again:

  static Method* method_for_itable_index(Klass* klass, int itable_index);

  // Debugging/Statistics

  static void print_statistics() PRODUCT_RETURN;

 private:

  intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }

  intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }

  // Helper methods

  static int  calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }

  // Statistics

  NOT_PRODUCT(static int  _total_classes;)   // Total no. of classes with itables

  NOT_PRODUCT(static long _total_size;)      // Total no. of bytes used for itables

  static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })

 public:

#ifndef PRODUCT

  bool check_no_old_entries();

#endif

};

#endif // SHARE_VM_OOPS_KLASSVTABLE_HPP