/*

 * Copyright 2008-2010 Sun Microsystems, Inc.  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 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.

 *

 */

// Low-level parser for method handle chains.

class MethodHandleChain : StackObj {

public:

  typedef MethodHandles::EntryKind EntryKind;

private:

  Handle        _root;          // original target

  Handle        _method_handle; // current target

  bool          _is_last;       // final guy in chain

  bool          _is_bound;      // has a bound argument

  BasicType     _arg_type;      // if is_bound, the bound argument type

  int           _arg_slot;      // if is_bound or is_adapter, affected argument slot

  jint          _conversion;    // conversion field of AMH or -1

  methodHandle  _last_method;   // if is_last, which method we target

  Bytecodes::Code _last_invoke; // if is_last, type of invoke

  const char*   _lose_message;  // saved argument to lose()

  void set_method_handle(Handle target, TRAPS);

  void set_last_method(oop target, TRAPS);

  static BasicType compute_bound_arg_type(oop target, methodOop m, int arg_slot, TRAPS);

  oop MethodHandle_type_oop()     { return java_dyn_MethodHandle::type(method_handle_oop()); }

  oop MethodHandle_vmtarget_oop() { return java_dyn_MethodHandle::vmtarget(method_handle_oop()); }

  int MethodHandle_vmslots()      { return java_dyn_MethodHandle::vmslots(method_handle_oop()); }

  int DirectMethodHandle_vmindex()     { return sun_dyn_DirectMethodHandle::vmindex(method_handle_oop()); }

  oop BoundMethodHandle_argument_oop() { return sun_dyn_BoundMethodHandle::argument(method_handle_oop()); }

  int BoundMethodHandle_vmargslot()    { return sun_dyn_BoundMethodHandle::vmargslot(method_handle_oop()); }

  int AdapterMethodHandle_conversion() { return sun_dyn_AdapterMethodHandle::conversion(method_handle_oop()); }

public:

  MethodHandleChain(Handle root, TRAPS)

    : _root(root)

  { set_method_handle(root, THREAD); }

  bool is_adapter()             { return _conversion != -1; }

  bool is_bound()               { return _is_bound; }

  bool is_last()                { return _is_last; }

  void next(TRAPS) {

    assert(!is_last(), "");

    set_method_handle(MethodHandle_vmtarget_oop(), THREAD);

  }

  Handle method_handle()        { return _method_handle; }

  oop    method_handle_oop()    { return _method_handle(); }

  oop    method_type_oop()      { return MethodHandle_type_oop(); }

  jint adapter_conversion()     { assert(is_adapter(), ""); return _conversion; }

  int  adapter_conversion_op()  { return MethodHandles::adapter_conversion_op(adapter_conversion()); }

  BasicType adapter_conversion_src_type()

                                { return MethodHandles::adapter_conversion_src_type(adapter_conversion()); }

  BasicType adapter_conversion_dest_type()

                                { return MethodHandles::adapter_conversion_dest_type(adapter_conversion()); }

  int  adapter_conversion_stack_move()

                                { return MethodHandles::adapter_conversion_stack_move(adapter_conversion()); }

  int  adapter_conversion_stack_pushes()

                                { return adapter_conversion_stack_move() / MethodHandles::stack_move_unit(); }

  int  adapter_conversion_vminfo()

                                { return MethodHandles::adapter_conversion_vminfo(adapter_conversion()); }

  int adapter_arg_slot()        { assert(is_adapter(), ""); return _arg_slot; }

  oop adapter_arg_oop()         { assert(is_adapter(), ""); return BoundMethodHandle_argument_oop(); }

  BasicType bound_arg_type()    { assert(is_bound(), ""); return _arg_type; }

  int       bound_arg_slot()    { assert(is_bound(), ""); return _arg_slot; }

  oop       bound_arg_oop()     { assert(is_bound(), ""); return BoundMethodHandle_argument_oop(); }

  methodOop last_method_oop()   { assert(is_last(), ""); return _last_method(); }

  Bytecodes::Code last_invoke_code() { assert(is_last(), ""); return _last_invoke; }

  void lose(const char* msg, TRAPS);

  const char* lose_message()    { return _lose_message; }

};

// Structure walker for method handles.

// Does abstract interpretation on top of low-level parsing.

// You supply the tokens shuffled by the abstract interpretation.

class MethodHandleWalker : StackObj {

public:

  // Abstract interpretation state:

  struct SlotState {

    BasicType _type;

    ArgToken  _arg;

    SlotState() : _type(), _arg() {}

  };

  static SlotState make_state(BasicType type, ArgToken arg) {

    SlotState ss;

    ss._type = type; ss._arg = arg;

    return ss;

  }

private:

  MethodHandleChain _chain;

  int                      _outgoing_argc;  // # non-empty outgoing slots

  // Replace a value of type old_type at slot (and maybe slot+1) with the new value.

  // If old_type != T_VOID, remove the old argument at that point.

  // If new_type != T_VOID, insert the new argument at that point.

  // Insert or delete a second empty slot as needed.

  SlotState* slot_state(int slot) {

    if (slot < 0 || slot >= _outgoing.length())

      return NULL;

    return _outgoing.adr_at(slot);

  }

  BasicType slot_type(int slot) {

    SlotState* ss = slot_state(slot);

    if (ss == NULL)

      return T_ILLEGAL;

    return ss->_type;

  }

  bool slot_has_argument(int slot) {

    return slot_type(slot) < T_VOID;

  }

#ifdef ASSERT

  int argument_count_slow();

#endif

  // Return a bytecode for converting src to dest, if one exists.

  Bytecodes::Code conversion_code(BasicType src, BasicType dest);

  void walk_incoming_state(TRAPS);

public:

    : _chain(root, THREAD),

      _outgoing(THREAD, 10),

      _outgoing_argc(0)

  MethodHandleChain& chain() { return _chain; }

  // plug-in abstract interpretation steps:

  virtual ArgToken make_parameter( BasicType type, klassOop tk, int argnum, TRAPS ) = 0;

  virtual ArgToken make_prim_constant( BasicType type, jvalue* con, TRAPS ) = 0;

  virtual ArgToken make_oop_constant( oop con, TRAPS ) = 0;

  virtual ArgToken make_invoke( methodOop m, vmIntrinsics::ID iid, Bytecodes::Code op, bool tailcall, int argc, ArgToken* argv, TRAPS ) = 0;

  // For make_invoke, the methodOop can be NULL if the intrinsic ID

  // is something other than vmIntrinsics::_none.

  // and in case anyone cares to related the previous actions to the chain:

  virtual void set_method_handle(oop mh) { }

  void lose(const char* msg, TRAPS) { chain().lose(msg, THREAD); }

  const char* lose_message()        { return chain().lose_message(); }

  ArgToken walk(TRAPS);

};

// An abstract interpreter for method handle chains.

// Produces an account of the semantics of a chain, in terms of a static IR.

// The IR happens to be JVM bytecodes.

class MethodHandleCompiler : public MethodHandleWalker {

private:

  };

  // Accumulated compiler state:

  int _max_stack;

  int _num_params;

  int _name_index;

  int _signature_index;

  }

  virtual ArgToken make_parameter(BasicType type, klassOop tk, int argnum, TRAPS) {

  }

  virtual ArgToken make_oop_constant(oop con, TRAPS) {

  }

  virtual ArgToken make_prim_constant(BasicType type, jvalue* con, TRAPS) {

  }

  virtual ArgToken make_invoke(methodOop m, vmIntrinsics::ID iid, Bytecodes::Code op, bool tailcall, int argc, ArgToken* argv, TRAPS);

public:

  // Compile the given MH chain into bytecode.

};