/*

 * Copyright 1997-2006 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.

 *

 */

// SignatureIterators iterate over a Java signature (or parts of it).

// (Syntax according to: "The Java Virtual Machine Specification" by

// Tim Lindholm & Frank Yellin; section 4.3 Descriptors; p. 89ff.)

//

// Example: Iterating over ([Lfoo;D)I using

//                         0123456789

//

// iterate_parameters() calls: do_array(2, 7); do_double();

// iterate_returntype() calls:                              do_int();

// iterate()            calls: do_array(2, 7); do_double(); do_int();

//

// is_return_type()        is: false         ; false      ; true

//

// NOTE: The new optimizer has an alternate, for-loop based signature

// iterator implemented in opto/type.cpp, TypeTuple::make().

class SignatureIterator: public ResourceObj {

 protected:

  symbolHandle _signature;             // the signature to iterate over

  int          _index;                 // the current character index (only valid during iteration)

  int          _parameter_index;       // the current parameter index (0 outside iteration phase)

  BasicType    _return_type;

  void expect(char c);

  void skip_optional_size();

  int  parse_type();                   // returns the parameter size in words (0 for void)

  void check_signature_end();

 public:

  // Definitions used in generating and iterating the

  // bit field form of the signature generated by the

  // Fingerprinter.

  enum {

    static_feature_size    = 1,

    result_feature_size    = 4,

    result_feature_mask    = 0xF,

    parameter_feature_size = 4,

    parameter_feature_mask = 0xF,

      bool_parm            = 1,

      byte_parm            = 2,

      char_parm            = 3,

      short_parm           = 4,

      int_parm             = 5,

      long_parm            = 6,

      float_parm           = 7,

      double_parm          = 8,

      obj_parm             = 9,

      done_parm            = 10,  // marker for end of parameters

    // max parameters is wordsize minus

    //    The sign bit, termination field, the result and static bit fields

    max_size_of_parameters = (BitsPerLong-1 -

                              result_feature_size - parameter_feature_size -

                              static_feature_size) / parameter_feature_size

  };

  // Constructors

  SignatureIterator(symbolOop signature);

  SignatureIterator(Thread *thread, symbolOop signature);

  SignatureIterator(symbolHandle signature);

  // Iteration

  void dispatch_field();               // dispatches once for field signatures

  void iterate_parameters();           // iterates over parameters only

  void iterate_parameters( uint64_t fingerprint );

  void iterate_returntype();           // iterates over returntype only

  void iterate();                      // iterates over whole signature

  // Returns the word index of the current parameter;

  int  parameter_index() const         { return _parameter_index; }

  bool is_return_type() const          { return parameter_index() < 0; }

  BasicType get_ret_type() const       { return _return_type; }

  // Basic types

  virtual void do_bool  ()             = 0;

  virtual void do_char  ()             = 0;

  virtual void do_float ()             = 0;

  virtual void do_double()             = 0;

  virtual void do_byte  ()             = 0;

  virtual void do_short ()             = 0;

  virtual void do_int   ()             = 0;

  virtual void do_long  ()             = 0;

  virtual void do_void  ()             = 0;

  // Object types (begin indexes the first character of the entry, end indexes the first character after the entry)

  virtual void do_object(int begin, int end) = 0;

  virtual void do_array (int begin, int end) = 0;

};

// Specialized SignatureIterators: Used to compute signature specific values.

class SignatureTypeNames : public SignatureIterator {

 protected:

  virtual void type_name(const char* name)   = 0;

  void do_bool()                       { type_name("jboolean"); }

  void do_char()                       { type_name("jchar"   ); }

  void do_float()                      { type_name("jfloat"  ); }

  void do_double()                     { type_name("jdouble" ); }

  void do_byte()                       { type_name("jbyte"   ); }

  void do_short()                      { type_name("jshort"  ); }

  void do_int()                        { type_name("jint"    ); }

  void do_long()                       { type_name("jlong"   ); }

  void do_void()                       { type_name("void"    ); }

  void do_object(int begin, int end)   { type_name("jobject" ); }

  void do_array (int begin, int end)   { type_name("jobject" ); }

 public:

  SignatureTypeNames(symbolHandle signature) : SignatureIterator(signature) {}

};

class SignatureInfo: public SignatureIterator {

 protected:

  bool      _has_iterated;             // need this because iterate cannot be called in constructor (set is virtual!)

  bool      _has_iterated_return;

  int       _size;

  void lazy_iterate_parameters()       { if (!_has_iterated) { iterate_parameters(); _has_iterated = true; } }

  void lazy_iterate_return()           { if (!_has_iterated_return) { iterate_returntype(); _has_iterated_return = true; } }

  virtual void set(int size, BasicType type) = 0;

  void do_bool  ()                     { set(T_BOOLEAN_size, T_BOOLEAN); }

  void do_char  ()                     { set(T_CHAR_size   , T_CHAR   ); }

  void do_float ()                     { set(T_FLOAT_size  , T_FLOAT  ); }

  void do_double()                     { set(T_DOUBLE_size , T_DOUBLE ); }

  void do_byte  ()                     { set(T_BYTE_size   , T_BYTE   ); }

  void do_short ()                     { set(T_SHORT_size  , T_SHORT  ); }

  void do_int   ()                     { set(T_INT_size    , T_INT    ); }

  void do_long  ()                     { set(T_LONG_size   , T_LONG   ); }

  void do_void  ()                     { set(T_VOID_size   , T_VOID   ); }

  void do_object(int begin, int end)   { set(T_OBJECT_size , T_OBJECT ); }

  void do_array (int begin, int end)   { set(T_ARRAY_size  , T_ARRAY  ); }

 public:

  SignatureInfo(symbolHandle signature) : SignatureIterator(signature) {

    _has_iterated = _has_iterated_return = false;

    _size         = 0;

    _return_type  = T_ILLEGAL;

  }

};

// Specialized SignatureIterator: Used to compute the argument size.

class ArgumentSizeComputer: public SignatureInfo {

 private:

  void set(int size, BasicType type)   { _size += size; }

 public:

  ArgumentSizeComputer(symbolHandle signature) : SignatureInfo(signature) {}

  int       size()                     { lazy_iterate_parameters(); return _size; }

};

class ArgumentCount: public SignatureInfo {

 private:

  void set(int size, BasicType type)   { _size ++; }

 public:

  ArgumentCount(symbolHandle signature) : SignatureInfo(signature) {}

  int       size()                     { lazy_iterate_parameters(); return _size; }

};

// Specialized SignatureIterator: Used to compute the result type.

class ResultTypeFinder: public SignatureInfo {

 private:

  void set(int size, BasicType type)   { _return_type = type; }

 public:

  BasicType type()                     { lazy_iterate_return(); return _return_type; }

  ResultTypeFinder(symbolHandle signature) : SignatureInfo(signature) {}

};

// Fingerprinter computes a unique ID for a given method. The ID

// is a bitvector characterizing the methods signature (incl. the receiver).

class Fingerprinter: public SignatureIterator {

 private:

  uint64_t _fingerprint;

  int _shift_count;

  methodHandle mh;

 public:

  void do_bool()    { _fingerprint |= (((uint64_t)bool_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_char()    { _fingerprint |= (((uint64_t)char_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_byte()    { _fingerprint |= (((uint64_t)byte_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_short()   { _fingerprint |= (((uint64_t)short_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_int()     { _fingerprint |= (((uint64_t)int_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_long()    { _fingerprint |= (((uint64_t)long_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_float()   { _fingerprint |= (((uint64_t)float_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_double()  { _fingerprint |= (((uint64_t)double_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_object(int begin, int end)  { _fingerprint |= (((uint64_t)obj_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_array (int begin, int end)  { _fingerprint |= (((uint64_t)obj_parm) << _shift_count); _shift_count += parameter_feature_size; }

  void do_void()    { ShouldNotReachHere(); }

  Fingerprinter(methodHandle method) : SignatureIterator(method->signature()) {

    mh = method;

    _fingerprint = 0;

  }

  Fingerprinter(Thread *thread, methodHandle method) : SignatureIterator(thread, method->signature()) {

    mh = method;

    _fingerprint = 0;

  }

  uint64_t fingerprint() {

    // See if we fingerprinted this method already

    if (mh->constMethod()->fingerprint() != CONST64(0)) {

      return mh->constMethod()->fingerprint();

    }

    if (mh->size_of_parameters() > max_size_of_parameters ) {

      _fingerprint = UCONST64(-1);

      mh->constMethod()->set_fingerprint(_fingerprint);

      return _fingerprint;

    }

    assert( (int)mh->result_type() <= (int)result_feature_mask, "bad result type");

    _fingerprint = mh->result_type();

    _fingerprint <<= static_feature_size;

    if (mh->is_static())  _fingerprint |= 1;

    _shift_count = result_feature_size + static_feature_size;

    iterate_parameters();

    _fingerprint |= ((uint64_t)done_parm) << _shift_count;// mark end of sig

    mh->constMethod()->set_fingerprint(_fingerprint);

    return _fingerprint;

  }

};

// Specialized SignatureIterator: Used for native call purposes

class NativeSignatureIterator: public SignatureIterator {

 private:

  methodHandle _method;

// We need separate JNI and Java offset values because in 64 bit mode,

// the argument offsets are not in sync with the Java stack.

// For example a long takes up 1 "C" stack entry but 2 Java stack entries.

  int          _offset;                // The java stack offset

  int          _prepended;             // number of prepended JNI parameters (1 JNIEnv, plus 1 mirror if static)

  int          _jni_offset;            // the current parameter offset, starting with 0

  void do_bool  ()                     { pass_int();    _jni_offset++; _offset++;       }

  void do_char  ()                     { pass_int();    _jni_offset++; _offset++;       }

#if defined(_LP64) || defined(ZERO)

  void do_float ()                     { pass_float();  _jni_offset++; _offset++;       }

#else

  void do_float ()                     { pass_int();    _jni_offset++; _offset++;       }

#endif

#ifdef _LP64

  void do_double()                     { pass_double(); _jni_offset++; _offset += 2;    }

#else

  void do_double()                     { pass_double(); _jni_offset += 2; _offset += 2; }

#endif

  void do_byte  ()                     { pass_int();    _jni_offset++; _offset++;       }

  void do_short ()                     { pass_int();    _jni_offset++; _offset++;       }

  void do_int   ()                     { pass_int();    _jni_offset++; _offset++;       }

#ifdef _LP64

  void do_long  ()                     { pass_long();   _jni_offset++; _offset += 2;    }

#else

  void do_long  ()                     { pass_long();   _jni_offset += 2; _offset += 2; }

#endif

  void do_void  ()                     { ShouldNotReachHere();                               }

  void do_object(int begin, int end)   { pass_object(); _jni_offset++; _offset++;        }

  void do_array (int begin, int end)   { pass_object(); _jni_offset++; _offset++;        }

 public:

  methodHandle method() const          { return _method; }

  int          offset() const          { return _offset; }

  int      jni_offset() const          { return _jni_offset + _prepended; }

//  int     java_offset() const          { return method()->size_of_parameters() - _offset - 1; }

  bool      is_static() const          { return method()->is_static(); }

  virtual void pass_int()              = 0;

  virtual void pass_long()             = 0;

  virtual void pass_object()           = 0;

#if defined(_LP64) || defined(ZERO)

  virtual void pass_float()            = 0;

#endif

#ifdef _LP64

  virtual void pass_double()           = 0;

#else

  virtual void pass_double()           { pass_long(); }  // may be same as long

#endif

  NativeSignatureIterator(methodHandle method) : SignatureIterator(method->signature()) {

    _method = method;

    _offset = 0;

    _jni_offset = 0;

    const int JNIEnv_words = 1;

    const int mirror_words = 1;

    _prepended = !is_static() ? JNIEnv_words : JNIEnv_words + mirror_words;

  }

  // iterate() calles the 2 virtual methods according to the following invocation syntax:

  //

  // {pass_int | pass_long | pass_object}

  //

  // Arguments are handled from left to right (receiver first, if any).

  // The offset() values refer to the Java stack offsets but are 0 based and increasing.

  // The java_offset() values count down to 0, and refer to the Java TOS.

  // The jni_offset() values increase from 1 or 2, and refer to C arguments.

  void iterate() { iterate(Fingerprinter(method()).fingerprint());

  }

  // Optimized path if we have the bitvector form of signature

  void iterate( uint64_t fingerprint ) {

    if (!is_static()) {

      // handle receiver (not handled by iterate because not in signature)

      pass_object(); _jni_offset++; _offset++;

    }

    SignatureIterator::iterate_parameters( fingerprint );

  }

};

// Handy stream for iterating over signature

class SignatureStream : public StackObj {

 private:

  symbolHandle _signature;

  int          _begin;

  int          _end;

  BasicType    _type;

  bool         _at_return_type;

 public:

  bool at_return_type() const                    { return _at_return_type; }

  bool is_done() const;

  void next_non_primitive(int t);

  void next() {

    symbolOop sig = _signature();

    int len = sig->utf8_length();

    if (_end >= len) {

      _end = len + 1;

      return;

    }

    _begin = _end;

    int t = sig->byte_at(_begin);

    switch (t) {

      case 'B': _type = T_BYTE;    break;

      case 'C': _type = T_CHAR;    break;

      case 'D': _type = T_DOUBLE;  break;

      case 'F': _type = T_FLOAT;   break;

      case 'I': _type = T_INT;     break;

      case 'J': _type = T_LONG;    break;

      case 'S': _type = T_SHORT;   break;

      case 'Z': _type = T_BOOLEAN; break;

      case 'V': _type = T_VOID;    break;

      default : next_non_primitive(t);

                return;

    }

    _end++;

  }

  SignatureStream(symbolHandle signature,

                  bool is_method = true) :

                   _signature(signature), _at_return_type(false) {

    _begin = _end = (is_method ? 1 : 0);  // skip first '(' in method signatures

    next();

  }

  bool is_object() const;                        // True if this argument is an object

  bool is_array() const;                         // True if this argument is an array

  BasicType type() const                         { return _type; }

  symbolOop as_symbol(TRAPS);

  // return same as_symbol except allocation of new symbols is avoided.

  symbolOop as_symbol_or_null();

};

class SignatureVerifier : public StackObj {

  public:

    // Returns true if the symbol is valid method or type signature

    static bool is_valid_signature(symbolHandle sig);

    static bool is_valid_method_signature(symbolHandle sig);

    static bool is_valid_type_signature(symbolHandle sig);

  private:

    static ssize_t is_valid_type(const char*, ssize_t);

    static bool invalid_name_char(char);

};