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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 *

 * 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.

 *

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#ifndef SHARE_VM_PRIMS_METHODHANDLEWALK_HPP

#define SHARE_VM_PRIMS_METHODHANDLEWALK_HPP

#include "prims/methodHandles.hpp"

// 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);

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(); }

  oop    vmtarget_oop()         { return MethodHandle_vmtarget_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:

  // Stack values:

  enum TokenType {

    tt_void,

    tt_parameter,

    tt_temporary,

    tt_constant,

    tt_illegal

  };

  // Argument token:

  class ArgToken {

  private:

    TokenType _tt;

    BasicType _bt;

    jvalue    _value;

    Handle    _handle;

  public:

    ArgToken(TokenType tt = tt_illegal) : _tt(tt) {}

    ArgToken(TokenType tt, BasicType bt, jvalue value) : _tt(tt), _bt(bt), _value(value) {}

    ArgToken(TokenType tt, BasicType bt, int index) : _tt(tt), _bt(bt) {

      _value.i = index;

    }

    ArgToken(TokenType tt, BasicType bt, Handle value) : _tt(tt), _bt(bt) {

      _handle = value;

    }

    TokenType token_type()  const { return _tt; }

    BasicType basic_type()  const { return _bt; }

    int       index()       const { return _value.i; }

    Handle    object()      const { return _handle; }

    jint      get_jint()    const { return _value.i; }

    jlong     get_jlong()   const { return _value.j; }

    jfloat    get_jfloat()  const { return _value.f; }

    jdouble   get_jdouble() const { return _value.d; }

  };

  // 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;

  bool              _for_invokedynamic;

  int               _local_index;

  GrowableArray<SlotState> _outgoing;       // current outgoing parameter slots

  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.

  void change_argument(BasicType old_type, int slot, BasicType new_type, const ArgToken& new_arg);

  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:

  MethodHandleWalker(Handle root, bool for_invokedynamic, TRAPS)

    : _chain(root, THREAD),

      _for_invokedynamic(for_invokedynamic),

      _outgoing(THREAD, 10),

      _outgoing_argc(0)

  {

    _local_index = for_invokedynamic ? 0 : 1;

  }

  MethodHandleChain& chain() { return _chain; }

  bool for_invokedynamic() const { return _for_invokedynamic; }

  int new_local_index(BasicType bt) {

    //int index = _for_invokedynamic ? _local_index : _local_index - 1;

    int index = _local_index;

    _local_index += type2size[bt];

    return index;

  }

  int max_locals() const { return _local_index; }

  // 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_conversion( BasicType type, klassOop tk, Bytecodes::Code op, const ArgToken& src, TRAPS ) = 0;

  virtual ArgToken make_fetch( BasicType type, klassOop tk, Bytecodes::Code op, const ArgToken& base, const ArgToken& offset, 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:

  methodHandle _callee;

  KlassHandle  _rklass;        // Return type for casting.

  BasicType    _rtype;

  KlassHandle  _target_klass;

  Thread*      _thread;

  // Fake constant pool entry.

  class ConstantValue {

  private:

    int       _tag;   // Constant pool tag type.

    JavaValue _value;

    Handle    _handle;

    Symbol*   _sym;

  public:

    // Constructor for oop types.

    ConstantValue(int tag, Handle con) : _tag(tag), _handle(con) {

      assert(tag == JVM_CONSTANT_Class  ||

             tag == JVM_CONSTANT_String ||

             tag == JVM_CONSTANT_Object, "must be oop type");

    }

    ConstantValue(int tag, Symbol* con) : _tag(tag), _sym(con) {

      assert(tag == JVM_CONSTANT_Utf8, "must be symbol type");

    }

    // Constructor for oop reference types.

    ConstantValue(int tag, int index) : _tag(tag) {

      assert(JVM_CONSTANT_Fieldref <= tag && tag <= JVM_CONSTANT_NameAndType, "must be ref type");

      _value.set_jint(index);

    }

    ConstantValue(int tag, int first_index, int second_index) : _tag(tag) {

      assert(JVM_CONSTANT_Fieldref <= tag && tag <= JVM_CONSTANT_NameAndType, "must be ref type");

      _value.set_jint(first_index << 16 | second_index);

    }

    // Constructor for primitive types.

    ConstantValue(BasicType bt, jvalue con) {

      _value.set_type(bt);

      switch (bt) {

      case T_INT:    _tag = JVM_CONSTANT_Integer; _value.set_jint(   con.i); break;

      case T_LONG:   _tag = JVM_CONSTANT_Long;    _value.set_jlong(  con.j); break;

      case T_FLOAT:  _tag = JVM_CONSTANT_Float;   _value.set_jfloat( con.f); break;

      case T_DOUBLE: _tag = JVM_CONSTANT_Double;  _value.set_jdouble(con.d); break;

      default: ShouldNotReachHere();

      }

    }

    int       tag()          const { return _tag; }

    Symbol*   symbol()       const { return _sym; }

    klassOop  klass_oop()    const { return (klassOop)  _handle(); }

    oop       object_oop()   const { return _handle(); }

    int       index()        const { return _value.get_jint(); }

    int       first_index()  const { return _value.get_jint() >> 16; }

    int       second_index() const { return _value.get_jint() & 0x0000FFFF; }

    bool      is_primitive() const { return is_java_primitive(_value.get_type()); }

    jint      get_jint()     const { return _value.get_jint();    }

    jlong     get_jlong()    const { return _value.get_jlong();   }

    jfloat    get_jfloat()   const { return _value.get_jfloat();  }

    jdouble   get_jdouble()  const { return _value.get_jdouble(); }

  };

  // Fake constant pool.

  GrowableArray<ConstantValue*> _constants;

  // Accumulated compiler state:

  GrowableArray<unsigned char> _bytecode;

  int _cur_stack;

  int _max_stack;

  int _num_params;

  int _name_index;

  int _signature_index;

  void stack_push(BasicType bt) {

    _cur_stack += type2size[bt];

    if (_cur_stack > _max_stack) _max_stack = _cur_stack;

  }

  void stack_pop(BasicType bt) {

    _cur_stack -= type2size[bt];

    assert(_cur_stack >= 0, "sanity");

  }

  unsigned char* bytecode()        const { return _bytecode.adr_at(0); }

  int            bytecode_length() const { return _bytecode.length(); }

  // Fake constant pool.

  int cpool_oop_put(int tag, Handle con) {

    if (con.is_null())  return 0;

    ConstantValue* cv = new ConstantValue(tag, con);

    return _constants.append(cv);

  }

  int cpool_symbol_put(int tag, Symbol* con) {

    if (con == NULL)  return 0;

    ConstantValue* cv = new ConstantValue(tag, con);

    return _constants.append(cv);

  }

  int cpool_oop_reference_put(int tag, int first_index, int second_index) {

    if (first_index == 0 && second_index == 0)  return 0;

    assert(first_index != 0 && second_index != 0, "no zero indexes");

    ConstantValue* cv = new ConstantValue(tag, first_index, second_index);

    return _constants.append(cv);

  }

  int cpool_primitive_put(BasicType type, jvalue* con);

  int cpool_int_put(jint value) {

    jvalue con; con.i = value;

    return cpool_primitive_put(T_INT, &con);

  }

  int cpool_long_put(jlong value) {

    jvalue con; con.j = value;

    return cpool_primitive_put(T_LONG, &con);

  }

  int cpool_float_put(jfloat value) {

    jvalue con; con.f = value;

    return cpool_primitive_put(T_FLOAT, &con);

  }

  int cpool_double_put(jdouble value) {

    jvalue con; con.d = value;

    return cpool_primitive_put(T_DOUBLE, &con);

  }

  int cpool_object_put(Handle obj) {

    return cpool_oop_put(JVM_CONSTANT_Object, obj);

  }

  int cpool_symbol_put(Symbol* sym) {

    return cpool_symbol_put(JVM_CONSTANT_Utf8, sym);

  }

  int cpool_klass_put(klassOop klass) {

    return cpool_oop_put(JVM_CONSTANT_Class, klass);

  }

  int cpool_methodref_put(int class_index, int name_and_type_index) {

    return cpool_oop_reference_put(JVM_CONSTANT_Methodref, class_index, name_and_type_index);

  }

  int cpool_name_and_type_put(int name_index, int signature_index) {

    return cpool_oop_reference_put(JVM_CONSTANT_NameAndType, name_index, signature_index);

  }

  void emit_bc(Bytecodes::Code op, int index = 0);

  void emit_load(BasicType bt, int index);

  void emit_store(BasicType bt, int index);

  void emit_load_constant(ArgToken arg);

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

    return ArgToken(tt_parameter, type, argnum);

  }

  virtual ArgToken make_oop_constant(oop con, TRAPS) {

    Handle h(THREAD, con);

    return ArgToken(tt_constant, T_OBJECT, h);

  }

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

    return ArgToken(tt_constant, type, *con);

  }

  virtual ArgToken make_conversion(BasicType type, klassOop tk, Bytecodes::Code op, const ArgToken& src, TRAPS);

  virtual ArgToken make_fetch(BasicType type, klassOop tk, Bytecodes::Code op, const ArgToken& base, const ArgToken& offset, TRAPS);

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

  // Get a real constant pool.

  constantPoolHandle get_constant_pool(TRAPS) const;

  // Get a real methodOop.

  methodHandle get_method_oop(TRAPS) const;

public:

  MethodHandleCompiler(Handle root, methodHandle call_method, bool for_invokedynamic, TRAPS);

  // Compile the given MH chain into bytecode.

  methodHandle compile(TRAPS);

  // Tests if the given class is a MH adapter holder.

  static bool klass_is_method_handle_adapter_holder(klassOop klass) {

    return (klass == SystemDictionary::MethodHandle_klass());

  }

};

#endif // SHARE_VM_PRIMS_METHODHANDLEWALK_HPP