text: /*
   * Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   *
   */
  
  #ifndef SHARE_VM_RUNTIME_SIGNATURE_HPP
  #define SHARE_VM_RUNTIME_SIGNATURE_HPP
  
  #include "memory/allocation.hpp"
  #include "oops/methodOop.hpp"
  #include "utilities/top.hpp"
  
  // 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:
    Symbol*      _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(Symbol* 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(Symbol* 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(Symbol* 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(Symbol* signature) : SignatureInfo(signature) {}
  
    int       size()                     { lazy_iterate_parameters(); return _size; }
  };
  
  
  class ArgumentCount: public SignatureInfo {
   private:
    void set(int size, BasicType type)   { _size ++; }
   public:
    ArgumentCount(Symbol* 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(Symbol* 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;
    }
  
    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++;       }
    void do_float ()                     { pass_float();  _jni_offset++; _offset++;       }
  #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;
    virtual void pass_float()            = 0;
  #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:
    Symbol*      _signature;
    int          _begin;
    int          _end;
    BasicType    _type;
    bool         _at_return_type;
    GrowableArray<Symbol*>* _names;  // symbols created while parsing signature
  
   public:
    bool at_return_type() const                    { return _at_return_type; }
    bool is_done() const;
    void next_non_primitive(int t);
    void next() {
      Symbol* 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(Symbol* signature, bool is_method = true);
    ~SignatureStream();
  
    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; }
    Symbol* as_symbol(TRAPS);
    enum FailureMode { ReturnNull, CNFException, NCDFError };
    klassOop as_klass(Handle class_loader, Handle protection_domain, FailureMode failure_mode, TRAPS);
    oop as_java_mirror(Handle class_loader, Handle protection_domain, FailureMode failure_mode, TRAPS);
  
    // return same as_symbol except allocation of new symbols is avoided.
    Symbol* 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(Symbol* sig);
  
      static bool is_valid_method_signature(Symbol* sig);
      static bool is_valid_type_signature(Symbol* sig);
    private:
  
      static ssize_t is_valid_type(const char*, ssize_t);
      static bool invalid_name_char(char);
  };
  
  #endif // SHARE_VM_RUNTIME_SIGNATURE_HPP
  