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#ifndef SHARE_VM_OOPS_CPCACHEOOP_HPP

#define SHARE_VM_OOPS_CPCACHEOOP_HPP

#include "interpreter/bytecodes.hpp"

#include "memory/allocation.hpp"

#include "utilities/array.hpp"

// A ConstantPoolCacheEntry describes an individual entry of the constant

// pool cache. There's 2 principal kinds of entries: field entries for in-

// stance & static field access, and method entries for invokes. Some of

// the entry layout is shared and looks as follows:

//

// bit number |31                0|

// bit length |-8--|-8--|---16----|

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

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

//

// with:

// index  = original constant pool index

// b1     = bytecode 1

// b2     = bytecode 2

// psize  = parameters size (method entries only)

//          The index max is 0xffff (max number of fields in constant pool)

//

// The flags after TosState have the following interpretation:

// bit 27: 0 for fields, 1 for methods

// f  flag true if field is marked final

// v  flag true if field is volatile (only for fields)

// f2 flag true if f2 contains an oop (e.g., virtual final method)

// fv flag true if invokeinterface used for method in class Object

//

// The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the

// following mapping to the TosState states:

//

// btos: 0

// ctos: 1

// stos: 2

// itos: 3

// ltos: 4

// ftos: 5

// dtos: 6

// atos: 7

// vtos: 8

//

// Entry specific: field entries:

// _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index

// _f2      = field offset in bytes

// _flags   = field type information, original FieldInfo index in field holder

//            (field_index section)

//

// Entry specific: method entries:

// _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),

//            original constant pool index

//            for interface calls, which are essentially virtual but need a klass,

//            for invokedynamic, f1 contains a site-specific CallSite object (as an appendix)

//            for invokehandle, f1 contains a site-specific MethodType object (as an appendix)

//            (upcoming metadata changes will move the appendix to a separate array)

//            unused by non-virtual.  The is_vfinal flag indicates this is a

//            method pointer for a final method, not an index.

// _flags   = method type info (t section),

//            virtual final bit (vfinal),

//            parameter size (psize section)

//

// Note: invokevirtual & invokespecial bytecodes can share the same constant

//       pool entry and thus the same constant pool cache entry. All invoke

//       bytecodes but invokevirtual use only _f1 and the corresponding b1

//       bytecode, while invokevirtual uses only _f2 and the corresponding

//       b2 bytecode.  The value of _flags is shared for both types of entries.

//

// The fields are volatile so that they are stored in the order written in the

// source code.  The _indices field with the bytecode must be written last.

class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC {

  friend class VMStructs;

  friend class constantPoolCacheKlass;

 private:

  volatile intx     _indices;  // constant pool index & rewrite bytecodes

  volatile intx     _flags;    // flags

  void set_bytecode_1(Bytecodes::Code code);

  void set_bytecode_2(Bytecodes::Code code);

    assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");

  }

  void set_f2(intx f2)                           { assert(_f2 == 0 || _f2 == f2,            "illegal field change"); _f2 = f2; }

  int make_flags(TosState state, int option_bits, int field_index_or_method_params);

  void set_flags(intx flags)                     { _flags = flags; }

  bool init_flags_atomic(intx flags);

  void set_field_flags(TosState field_type, int option_bits, int field_index) {

    assert((field_index & field_index_mask) == field_index, "field_index in range");

    set_flags(make_flags(field_type, option_bits | (1 << is_field_entry_shift), field_index));

  }

  void set_method_flags(TosState return_type, int option_bits, int method_params) {

    assert((method_params & parameter_size_mask) == method_params, "method_params in range");

    set_flags(make_flags(return_type, option_bits, method_params));

  }

  bool init_method_flags_atomic(TosState return_type, int option_bits, int method_params) {

    assert((method_params & parameter_size_mask) == method_params, "method_params in range");

    return init_flags_atomic(make_flags(return_type, option_bits, method_params));

  }

 public:

  // specific bit definitions for the flags field:

  // (Note: the interpreter must use these definitions to access the CP cache.)

  enum {

    // high order bits are the TosState corresponding to field type or method return type

    tos_state_bits             = 4,

    tos_state_mask             = right_n_bits(tos_state_bits),

    tos_state_shift            = BitsPerInt - tos_state_bits,  // see verify_tos_state_shift below

    // misc. option bits; can be any bit position in [16..27]

    // low order bits give field index (for FieldInfo) or method parameter size:

    field_index_bits           = 16,

    field_index_mask           = right_n_bits(field_index_bits),

    parameter_size_bits        = 8,  // subset of field_index_mask, range is 0..255

    parameter_size_mask        = right_n_bits(parameter_size_bits),

    option_bits_mask           = ~(((-1) << tos_state_shift) | (field_index_mask | parameter_size_mask))

  };

  // specific bit definitions for the indices field:

  enum {

    bytecode_1_mask            = right_n_bits(BitsPerByte), // == (u1)0xFF

  };

  // Initialization

  void initialize_entry(int original_index);     // initialize primary entry

  void set_field(                                // sets entry to resolved field state

    Bytecodes::Code get_code,                    // the bytecode used for reading the field

    Bytecodes::Code put_code,                    // the bytecode used for writing the field

    KlassHandle     field_holder,                // the object/klass holding the field

    int             orig_field_index,            // the original field index in the field holder

    int             field_offset,                // the field offset in words in the field holder

    TosState        field_type,                  // the (machine) field type

    bool            is_final,                     // the field is final

  );

  void set_method(                               // sets entry to resolved method entry

    Bytecodes::Code invoke_code,                 // the bytecode used for invoking the method

    methodHandle    method,                      // the method/prototype if any (NULL, otherwise)

    int             vtable_index                 // the vtable index if any, else negative

  );

  void set_interface_call(

    methodHandle method,                         // Resolved method

    int index                                    // Method index into interface

  );

  void set_method_handle(

    methodHandle method,                         // adapter for invokeExact, etc.

  );

  void set_dynamic_call(

    methodHandle method,                         // adapter for this call site

  );

  // Common code for invokedynamic and MH invocations.

  // The "appendix" is an optional call-site-specific parameter which is

  // pushed by the JVM at the end of the argument list.  This argument may

  // be a MethodType for the MH.invokes and a CallSite for an invokedynamic

  // instruction.  However, its exact type and use depends on the Java upcall,

  // which simply returns a compiled LambdaForm along with any reference

  // that LambdaForm needs to complete the call.  If the upcall returns a

  // null appendix, the argument is not passed at all.

  //

  // The appendix is *not* represented in the signature of the symbolic

  // reference for the call site, but (if present) it *is* represented in

  // resolution logic needs to make slightly different assessments about the

  // number and types of arguments.

  void set_method_handle_common(

    Bytecodes::Code invoke_code,                 // _invokehandle or _invokedynamic

  );

  void set_parameter_size(int value);

  // Which bytecode number (1 or 2) in the index field is valid for this bytecode?

  // Returns -1 if neither is valid.

  static int bytecode_number(Bytecodes::Code code) {

    switch (code) {

      case Bytecodes::_getstatic       :    // fall through

      case Bytecodes::_getfield        :    // fall through

      case Bytecodes::_invokespecial   :    // fall through

      case Bytecodes::_invokestatic    :    // fall through

      case Bytecodes::_invokeinterface : return 1;

      case Bytecodes::_putstatic       :    // fall through

      case Bytecodes::_putfield        :    // fall through

      case Bytecodes::_invokehandle    :    // fall through

      case Bytecodes::_invokedynamic   :    // fall through

      case Bytecodes::_invokevirtual   : return 2;

      default                          : break;

    }

    return -1;

  }

  // Has this bytecode been resolved? Only valid for invokes and get/put field/static.

  bool is_resolved(Bytecodes::Code code) const {

    switch (bytecode_number(code)) {

      case 1:  return (bytecode_1() == code);

      case 2:  return (bytecode_2() == code);

    }

    return false;      // default: not resolved

  }

  // Accessors

  int       f2_as_index() const                  { assert(!is_vfinal(), ""); return (int) _f2; }

  int  field_index() const                       { assert(is_field_entry(),  ""); return (_flags & field_index_mask); }

  int  parameter_size() const                    { assert(is_method_entry(), ""); return (_flags & parameter_size_mask); }

  bool is_volatile() const                       { return (_flags & (1 << is_volatile_shift))       != 0; }

  bool is_final() const                          { return (_flags & (1 << is_final_shift))          != 0; }

  bool is_forced_virtual() const                 { return (_flags & (1 << is_forced_virtual_shift)) != 0; }

  bool is_vfinal() const                         { return (_flags & (1 << is_vfinal_shift))         != 0; }

  bool is_method_entry() const                   { return (_flags & (1 << is_field_entry_shift))    == 0; }

  bool is_field_entry() const                    { return (_flags & (1 << is_field_entry_shift))    != 0; }

  bool is_byte() const                           { return flag_state() == btos; }

  bool is_char() const                           { return flag_state() == ctos; }

  bool is_short() const                          { return flag_state() == stos; }

  bool is_int() const                            { return flag_state() == itos; }

  bool is_long() const                           { return flag_state() == ltos; }

  bool is_float() const                          { return flag_state() == ftos; }

  bool is_double() const                         { return flag_state() == dtos; }

  bool is_object() const                         { return flag_state() == atos; }

  TosState flag_state() const                    { assert((uint)number_of_states <= (uint)tos_state_mask+1, "");

                                                   return (TosState)((_flags >> tos_state_shift) & tos_state_mask); }

  // Code generation support

  static WordSize size()                         { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); }

  static ByteSize size_in_bytes()                { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); }

  static ByteSize indices_offset()               { return byte_offset_of(ConstantPoolCacheEntry, _indices); }

  static ByteSize f1_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f1); }

  static ByteSize f2_offset()                    { return byte_offset_of(ConstantPoolCacheEntry, _f2); }

  static ByteSize flags_offset()                 { return byte_offset_of(ConstantPoolCacheEntry, _flags); }

  // RedefineClasses() API support:

  // If this constantPoolCacheEntry refers to old_method then update it

  // to refer to 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.

         bool * trace_name_printed);

  // Debugging & Printing

  void print (outputStream* st, int index) const;

  void verify(outputStream* st) const;

  static void verify_tos_state_shift() {

    // When shifting flags as a 32-bit int, make sure we don't need an extra mask for tos_state:

    assert((((u4)-1 >> tos_state_shift) & ~tos_state_mask) == 0, "no need for tos_state mask");

  }

};

// A constant pool cache is a runtime data structure set aside to a constant pool. The cache

// holds interpreter runtime information for all field access and invoke bytecodes. The cache

// is created and initialized before a class is actively used (i.e., initialized), the indivi-

// dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).

  friend class VMStructs;

 private:

  int             _length;

  // Sizing

  debug_only(friend class ClassVerifier;)

 public:

  int length() const                             { return _length; }

 private:

  void set_length(int length)                    { _length = length; }

  // Helpers

  ConstantPoolCacheEntry* base() const           { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }

  friend class constantPoolCacheKlass;

  friend class ConstantPoolCacheEntry;

 public:

  // Initialization

  // Accessors

  // Fetches the entry at the given index.

  // In either case the index must not be encoded or byte-swapped in any way.

  ConstantPoolCacheEntry* entry_at(int i) const {

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

    return base() + i;

  }

  // Code generation

  static ByteSize entry_offset(int raw_index) {

    int index = raw_index;

    return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index);

  }

  // RedefineClasses() API support:

  // If any entry of this constantPoolCache 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.

                             int methods_length, bool * trace_name_printed);

};

#endif // SHARE_VM_OOPS_CPCACHEOOP_HPP