1 /*
   2  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_SIGNATURE_HPP
  26 #define SHARE_VM_RUNTIME_SIGNATURE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "oops/method.hpp"
  30 #include "utilities/top.hpp"
  31 
  32 // SignatureIterators iterate over a Java signature (or parts of it).
  33 // (Syntax according to: "The Java Virtual Machine Specification" by
  34 // Tim Lindholm & Frank Yellin; section 4.3 Descriptors; p. 89ff.)
  35 //
  36 // Example: Iterating over ([Lfoo;D)I using
  37 //                         0123456789
  38 //
  39 // iterate_parameters() calls: do_array(2, 7); do_double();
  40 // iterate_returntype() calls:                              do_int();
  41 // iterate()            calls: do_array(2, 7); do_double(); do_int();
  42 //
  43 // is_return_type()        is: false         ; false      ; true
  44 //
  45 // NOTE: The new optimizer has an alternate, for-loop based signature
  46 // iterator implemented in opto/type.cpp, TypeTuple::make().
  47 
  48 class SignatureIterator: public ResourceObj {
  49  protected:
  50   Symbol*      _signature;             // the signature to iterate over
  51   int          _index;                 // the current character index (only valid during iteration)
  52   int          _parameter_index;       // the current parameter index (0 outside iteration phase)
  53   BasicType    _return_type;
  54 
  55   void expect(char c);
  56   void skip_optional_size();
  57   int  parse_type();                   // returns the parameter size in words (0 for void)
  58   void check_signature_end();
  59 
  60  public:
  61   // Definitions used in generating and iterating the
  62   // bit field form of the signature generated by the
  63   // Fingerprinter.
  64   enum {
  65     static_feature_size    = 1,
  66     result_feature_size    = 4,
  67     result_feature_mask    = 0xF,
  68     parameter_feature_size = 4,
  69     parameter_feature_mask = 0xF,
  70 
  71       bool_parm            = 1,
  72       byte_parm            = 2,
  73       char_parm            = 3,
  74       short_parm           = 4,
  75       int_parm             = 5,
  76       long_parm            = 6,
  77       float_parm           = 7,
  78       double_parm          = 8,
  79       obj_parm             = 9,
  80       done_parm            = 10,  // marker for end of parameters
  81 
  82     // max parameters is wordsize minus
  83     //    The sign bit, termination field, the result and static bit fields
  84     max_size_of_parameters = (BitsPerLong-1 -
  85                               result_feature_size - parameter_feature_size -
  86                               static_feature_size) / parameter_feature_size
  87   };
  88 
  89   // Constructors
  90   SignatureIterator(Symbol* signature);
  91 
  92   // Iteration
  93   void dispatch_field();               // dispatches once for field signatures
  94   void iterate_parameters();           // iterates over parameters only
  95   void iterate_parameters( uint64_t fingerprint );
  96   void iterate_returntype();           // iterates over returntype only
  97   void iterate();                      // iterates over whole signature
  98   // Returns the word index of the current parameter;
  99   int  parameter_index() const         { return _parameter_index; }
 100   bool is_return_type() const          { return parameter_index() < 0; }
 101   BasicType get_ret_type() const       { return _return_type; }
 102 
 103   // Basic types
 104   virtual void do_bool  ()             = 0;
 105   virtual void do_char  ()             = 0;
 106   virtual void do_float ()             = 0;
 107   virtual void do_double()             = 0;
 108   virtual void do_byte  ()             = 0;
 109   virtual void do_short ()             = 0;
 110   virtual void do_int   ()             = 0;
 111   virtual void do_long  ()             = 0;
 112   virtual void do_void  ()             = 0;
 113 
 114   // Object types (begin indexes the first character of the entry, end indexes the first character after the entry)
 115   virtual void do_object(int begin, int end) = 0;
 116   virtual void do_array (int begin, int end) = 0;
 117 };
 118 
 119 
 120 // Specialized SignatureIterators: Used to compute signature specific values.
 121 
 122 class SignatureTypeNames : public SignatureIterator {
 123  protected:
 124   virtual void type_name(const char* name)   = 0;
 125 
 126   void do_bool()                       { type_name("jboolean"); }
 127   void do_char()                       { type_name("jchar"   ); }
 128   void do_float()                      { type_name("jfloat"  ); }
 129   void do_double()                     { type_name("jdouble" ); }
 130   void do_byte()                       { type_name("jbyte"   ); }
 131   void do_short()                      { type_name("jshort"  ); }
 132   void do_int()                        { type_name("jint"    ); }
 133   void do_long()                       { type_name("jlong"   ); }
 134   void do_void()                       { type_name("void"    ); }
 135   void do_object(int begin, int end)   { type_name("jobject" ); }
 136   void do_array (int begin, int end)   { type_name("jobject" ); }
 137 
 138  public:
 139   SignatureTypeNames(Symbol* signature) : SignatureIterator(signature) {}
 140 };
 141 
 142 
 143 class SignatureInfo: public SignatureIterator {
 144  protected:
 145   bool      _has_iterated;             // need this because iterate cannot be called in constructor (set is virtual!)
 146   bool      _has_iterated_return;
 147   int       _size;
 148 
 149   void lazy_iterate_parameters()       { if (!_has_iterated) { iterate_parameters(); _has_iterated = true; } }
 150   void lazy_iterate_return()           { if (!_has_iterated_return) { iterate_returntype(); _has_iterated_return = true; } }
 151 
 152   virtual void set(int size, BasicType type) = 0;
 153 
 154   void do_bool  ()                     { set(T_BOOLEAN_size, T_BOOLEAN); }
 155   void do_char  ()                     { set(T_CHAR_size   , T_CHAR   ); }
 156   void do_float ()                     { set(T_FLOAT_size  , T_FLOAT  ); }
 157   void do_double()                     { set(T_DOUBLE_size , T_DOUBLE ); }
 158   void do_byte  ()                     { set(T_BYTE_size   , T_BYTE   ); }
 159   void do_short ()                     { set(T_SHORT_size  , T_SHORT  ); }
 160   void do_int   ()                     { set(T_INT_size    , T_INT    ); }
 161   void do_long  ()                     { set(T_LONG_size   , T_LONG   ); }
 162   void do_void  ()                     { set(T_VOID_size   , T_VOID   ); }
 163   void do_object(int begin, int end)   { set(T_OBJECT_size , T_OBJECT ); }
 164   void do_array (int begin, int end)   { set(T_ARRAY_size  , T_ARRAY  ); }
 165 
 166  public:
 167   SignatureInfo(Symbol* signature) : SignatureIterator(signature) {
 168     _has_iterated = _has_iterated_return = false;
 169     _size         = 0;
 170     _return_type  = T_ILLEGAL;
 171   }
 172 
 173 };
 174 
 175 
 176 // Specialized SignatureIterator: Used to compute the argument size.
 177 
 178 class ArgumentSizeComputer: public SignatureInfo {
 179  private:
 180   void set(int size, BasicType type)   { _size += size; }
 181  public:
 182   ArgumentSizeComputer(Symbol* signature) : SignatureInfo(signature) {}
 183 
 184   int       size()                     { lazy_iterate_parameters(); return _size; }
 185 };
 186 
 187 
 188 class ArgumentCount: public SignatureInfo {
 189  private:
 190   void set(int size, BasicType type)   { _size ++; }
 191  public:
 192   ArgumentCount(Symbol* signature) : SignatureInfo(signature) {}
 193 
 194   int       size()                     { lazy_iterate_parameters(); return _size; }
 195 };
 196 
 197 
 198 // Specialized SignatureIterator: Used to compute the result type.
 199 
 200 class ResultTypeFinder: public SignatureInfo {
 201  private:
 202   void set(int size, BasicType type)   { _return_type = type; }
 203  public:
 204   BasicType type()                     { lazy_iterate_return(); return _return_type; }
 205 
 206   ResultTypeFinder(Symbol* signature) : SignatureInfo(signature) {}
 207 };
 208 
 209 
 210 // Fingerprinter computes a unique ID for a given method. The ID
 211 // is a bitvector characterizing the methods signature (incl. the receiver).
 212 class Fingerprinter: public SignatureIterator {
 213  private:
 214   uint64_t _fingerprint;
 215   int _shift_count;
 216   methodHandle mh;
 217 
 218  public:
 219 
 220   void do_bool()    { _fingerprint |= (((uint64_t)bool_parm) << _shift_count); _shift_count += parameter_feature_size; }
 221   void do_char()    { _fingerprint |= (((uint64_t)char_parm) << _shift_count); _shift_count += parameter_feature_size; }
 222   void do_byte()    { _fingerprint |= (((uint64_t)byte_parm) << _shift_count); _shift_count += parameter_feature_size; }
 223   void do_short()   { _fingerprint |= (((uint64_t)short_parm) << _shift_count); _shift_count += parameter_feature_size; }
 224   void do_int()     { _fingerprint |= (((uint64_t)int_parm) << _shift_count); _shift_count += parameter_feature_size; }
 225   void do_long()    { _fingerprint |= (((uint64_t)long_parm) << _shift_count); _shift_count += parameter_feature_size; }
 226   void do_float()   { _fingerprint |= (((uint64_t)float_parm) << _shift_count); _shift_count += parameter_feature_size; }
 227   void do_double()  { _fingerprint |= (((uint64_t)double_parm) << _shift_count); _shift_count += parameter_feature_size; }
 228 
 229   void do_object(int begin, int end)  { _fingerprint |= (((uint64_t)obj_parm) << _shift_count); _shift_count += parameter_feature_size; }
 230   void do_array (int begin, int end)  { _fingerprint |= (((uint64_t)obj_parm) << _shift_count); _shift_count += parameter_feature_size; }
 231 
 232   void do_void()    { ShouldNotReachHere(); }
 233 
 234   Fingerprinter(methodHandle method) : SignatureIterator(method->signature()) {
 235     mh = method;
 236     _fingerprint = 0;
 237   }
 238 
 239   uint64_t fingerprint() {
 240     // See if we fingerprinted this method already
 241     if (mh->constMethod()->fingerprint() != CONST64(0)) {
 242       return mh->constMethod()->fingerprint();
 243     }
 244 
 245     if (mh->size_of_parameters() > max_size_of_parameters ) {
 246       _fingerprint = UCONST64(-1);
 247       mh->constMethod()->set_fingerprint(_fingerprint);
 248       return _fingerprint;
 249     }
 250 
 251     assert( (int)mh->result_type() <= (int)result_feature_mask, "bad result type");
 252     _fingerprint = mh->result_type();
 253     _fingerprint <<= static_feature_size;
 254     if (mh->is_static())  _fingerprint |= 1;
 255     _shift_count = result_feature_size + static_feature_size;
 256     iterate_parameters();
 257     _fingerprint |= ((uint64_t)done_parm) << _shift_count;// mark end of sig
 258     mh->constMethod()->set_fingerprint(_fingerprint);
 259     return _fingerprint;
 260   }
 261 };
 262 
 263 
 264 // Specialized SignatureIterator: Used for native call purposes
 265 
 266 class NativeSignatureIterator: public SignatureIterator {
 267  private:
 268   methodHandle _method;
 269 // We need separate JNI and Java offset values because in 64 bit mode,
 270 // the argument offsets are not in sync with the Java stack.
 271 // For example a long takes up 1 "C" stack entry but 2 Java stack entries.
 272   int          _offset;                // The java stack offset
 273   int          _prepended;             // number of prepended JNI parameters (1 JNIEnv, plus 1 mirror if static)
 274   int          _jni_offset;            // the current parameter offset, starting with 0
 275 
 276   void do_bool  ()                     { pass_int();    _jni_offset++; _offset++;       }
 277   void do_char  ()                     { pass_int();    _jni_offset++; _offset++;       }
 278   void do_float ()                     { pass_float();  _jni_offset++; _offset++;       }
 279 #ifdef _LP64
 280   void do_double()                     { pass_double(); _jni_offset++; _offset += 2;    }
 281 #else
 282   void do_double()                     { pass_double(); _jni_offset += 2; _offset += 2; }
 283 #endif
 284   void do_byte  ()                     { pass_int();    _jni_offset++; _offset++;       }
 285   void do_short ()                     { pass_int();    _jni_offset++; _offset++;       }
 286   void do_int   ()                     { pass_int();    _jni_offset++; _offset++;       }
 287 #ifdef _LP64
 288   void do_long  ()                     { pass_long();   _jni_offset++; _offset += 2;    }
 289 #else
 290   void do_long  ()                     { pass_long();   _jni_offset += 2; _offset += 2; }
 291 #endif
 292   void do_void  ()                     { ShouldNotReachHere();                               }
 293   void do_object(int begin, int end)   { pass_object(); _jni_offset++; _offset++;        }
 294   void do_array (int begin, int end)   { pass_object(); _jni_offset++; _offset++;        }
 295 
 296  public:
 297   methodHandle method() const          { return _method; }
 298   int          offset() const          { return _offset; }
 299   int      jni_offset() const          { return _jni_offset + _prepended; }
 300 //  int     java_offset() const          { return method()->size_of_parameters() - _offset - 1; }
 301   bool      is_static() const          { return method()->is_static(); }
 302   virtual void pass_int()              = 0;
 303   virtual void pass_long()             = 0;
 304   virtual void pass_object()           = 0;
 305   virtual void pass_float()            = 0;
 306 #ifdef _LP64
 307   virtual void pass_double()           = 0;
 308 #else
 309   virtual void pass_double()           { pass_long(); }  // may be same as long
 310 #endif
 311 
 312   NativeSignatureIterator(methodHandle method) : SignatureIterator(method->signature()) {
 313     _method = method;
 314     _offset = 0;
 315     _jni_offset = 0;
 316 
 317     const int JNIEnv_words = 1;
 318     const int mirror_words = 1;
 319     _prepended = !is_static() ? JNIEnv_words : JNIEnv_words + mirror_words;
 320   }
 321 
 322   // iterate() calles the 2 virtual methods according to the following invocation syntax:
 323   //
 324   // {pass_int | pass_long | pass_object}
 325   //
 326   // Arguments are handled from left to right (receiver first, if any).
 327   // The offset() values refer to the Java stack offsets but are 0 based and increasing.
 328   // The java_offset() values count down to 0, and refer to the Java TOS.
 329   // The jni_offset() values increase from 1 or 2, and refer to C arguments.
 330 
 331   void iterate() { iterate(Fingerprinter(method()).fingerprint());
 332   }
 333 
 334 
 335   // Optimized path if we have the bitvector form of signature
 336   void iterate( uint64_t fingerprint ) {
 337 
 338     if (!is_static()) {
 339       // handle receiver (not handled by iterate because not in signature)
 340       pass_object(); _jni_offset++; _offset++;
 341     }
 342 
 343     SignatureIterator::iterate_parameters( fingerprint );
 344   }
 345 };
 346 
 347 
 348 // Handy stream for iterating over signature
 349 
 350 class SignatureStream : public StackObj {
 351  private:
 352   Symbol*      _signature;
 353   int          _begin;
 354   int          _end;
 355   BasicType    _type;
 356   bool         _at_return_type;
 357   GrowableArray<Symbol*>* _names;  // symbols created while parsing signature
 358 
 359  public:
 360   bool at_return_type() const                    { return _at_return_type; }
 361   bool is_done() const;
 362   void next_non_primitive(int t);
 363   void next() {
 364     Symbol* sig = _signature;
 365     int len = sig->utf8_length();
 366     if (_end >= len) {
 367       _end = len + 1;
 368       return;
 369     }
 370 
 371     _begin = _end;
 372     int t = sig->byte_at(_begin);
 373     switch (t) {
 374       case 'B': _type = T_BYTE;    break;
 375       case 'C': _type = T_CHAR;    break;
 376       case 'D': _type = T_DOUBLE;  break;
 377       case 'F': _type = T_FLOAT;   break;
 378       case 'I': _type = T_INT;     break;
 379       case 'J': _type = T_LONG;    break;
 380       case 'S': _type = T_SHORT;   break;
 381       case 'Z': _type = T_BOOLEAN; break;
 382       case 'V': _type = T_VOID;    break;
 383       default : next_non_primitive(t);
 384                 return;
 385     }
 386     _end++;
 387   }
 388 
 389   SignatureStream(Symbol* signature, bool is_method = true);
 390   ~SignatureStream();
 391 
 392   bool is_object() const;                        // True if this argument is an object
 393   bool is_array() const;                         // True if this argument is an array
 394   BasicType type() const                         { return _type; }
 395   Symbol* as_symbol(TRAPS);
 396   enum FailureMode { ReturnNull, CNFException, NCDFError };
 397   Klass* as_klass(Handle class_loader, Handle protection_domain, FailureMode failure_mode, TRAPS);
 398   oop as_java_mirror(Handle class_loader, Handle protection_domain, FailureMode failure_mode, TRAPS);
 399   const jbyte* raw_bytes()  { return _signature->bytes() + _begin; }
 400   int          raw_length() { return _end - _begin; }
 401 
 402   // return same as_symbol except allocation of new symbols is avoided.
 403   Symbol* as_symbol_or_null();
 404 
 405   // count the number of references in the signature
 406   int reference_parameter_count();
 407 };
 408 
 409 class SignatureVerifier : public StackObj {
 410   public:
 411     // Returns true if the symbol is valid method or type signature
 412     static bool is_valid_signature(Symbol* sig);
 413 
 414     static bool is_valid_method_signature(Symbol* sig);
 415     static bool is_valid_type_signature(Symbol* sig);
 416   private:
 417 
 418     static ssize_t is_valid_type(const char*, ssize_t);
 419     static bool invalid_name_char(char);
 420 };
 421 
 422 #endif // SHARE_VM_RUNTIME_SIGNATURE_HPP