libjava/include/java-interp.h

   1 // java-interp.h - Header file for the bytecode interpreter.  -*- c++ -*-
   2
   3 /* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 #ifndef __JAVA_INTERP_H__
  12 #define __JAVA_INTERP_H__
  13
  14 #include <jvm.h>
  15 #include <java-cpool.h>
  16 #include <gnu/gcj/runtime/NameFinder.h>
  17
  18 enum _Jv_FrameType
  19 {
  20   frame_native,
  21   frame_interpreter,
  22   frame_proxy
  23 };
  24
  25 #ifdef INTERPRETER
  26
  27 #pragma interface
  28
  29 #include <java/lang/Class.h>
  30 #include <java/lang/ClassLoader.h>
  31 #include <java/lang/reflect/Modifier.h>
  32 #include <java/lang/Thread.h>
  33 #include <gnu/gcj/RawData.h>
  34
  35 // Define this to get the direct-threaded interpreter.  If undefined,
  36 // we revert to a basic bytecode interpreter.  The former is faster
  37 // but uses more memory.
  38 #define DIRECT_THREADED
  39
  40 #include <ffi.h>
  41
  42 struct _Jv_ResolvedMethod;
  43
  44 void _Jv_InitInterpreter ();
  45 void _Jv_DefineClass (jclass, jbyteArray, jint, jint,
  46                       java::security::ProtectionDomain *,
  47                       _Jv_Utf8Const **);
  48
  49 void _Jv_InitField (jobject, jclass, int);
  50 void * _Jv_AllocMethodInvocation (jsize size);
  51 int  _Jv_count_arguments (_Jv_Utf8Const *signature,
  52                           jboolean staticp = true);
  53 void _Jv_VerifyMethod (_Jv_InterpMethod *method);
  54 void _Jv_CompileMethod (_Jv_InterpMethod* method);
  55 int _Jv_init_cif (_Jv_Utf8Const* signature,
  56                   int arg_count,
  57                   jboolean staticp,
  58                   ffi_cif *cif,
  59                   ffi_type **arg_types,
  60                   ffi_type **rtype_p);
  61
  62 /* the interpreter is written in C++, primarily because it makes it easy for
  63  * the entire thing to be "friend" with class Class. */
  64
  65 class _Jv_InterpClass;
  66 class _Jv_InterpMethod;
  67
  68 // Before a method is "compiled" we store values as the bytecode PC,
  69 // an int.  Afterwards we store them as pointers into the prepared
  70 // code itself.
  71 union _Jv_InterpPC
  72 {
  73   int i;
  74   void *p;
  75 };
  76
  77 class _Jv_InterpException
  78 {
  79   _Jv_InterpPC start_pc;
  80   _Jv_InterpPC end_pc;
  81   _Jv_InterpPC handler_pc;
  82   _Jv_InterpPC handler_type;
  83
  84   friend class _Jv_ClassReader;
  85   friend class _Jv_InterpMethod;
  86   friend class _Jv_BytecodeVerifier;
  87 };
  88
  89 // Base class for method representations.  Subclasses are interpreted
  90 // and JNI methods.
  91 class _Jv_MethodBase
  92 {
  93 protected:
  94   // The class which defined this method.
  95   jclass defining_class;
  96
  97   // The method description.
  98   _Jv_Method *self;
  99
 100   // Size of raw arguments.
 101   _Jv_ushort args_raw_size;
 102
 103   friend class _Jv_InterpreterEngine;
 104
 105 public:
 106   _Jv_Method *get_method ()
 107   {
 108     return self;
 109   }
 110 };
 111
 112 // The type of the PC depends on whether we're doing direct threading
 113 // or a more ordinary bytecode interpreter.
 114 #ifdef DIRECT_THREADED
 115 // Slot in the "compiled" form of the bytecode.
 116 union insn_slot
 117 {
 118   // Address of code.
 119   void *insn;
 120   // An integer value used by an instruction.
 121   jint int_val;
 122   // A pointer value used by an instruction.
 123   void *datum;
 124 };
 125
 126 typedef insn_slot *pc_t;
 127 #else
 128 typedef unsigned char *pc_t;
 129 #endif
 130
 131
 132 // This structure holds the bytecode pc and corresponding source code
 133 // line number.  An array (plus length field) of this structure is put
 134 // in each _Jv_InterpMethod and used to resolve the (internal) program
 135 // counter of the interpreted method to an actual java source file
 136 // line.
 137 struct  _Jv_LineTableEntry
 138 {
 139   union
 140   {
 141     pc_t pc;
 142     int bytecode_pc;
 143   };
 144   int line;
 145 };
 146
 147 // This structure holds local variable information.
 148 // Like _Jv_LineTableEntry above, it is remapped when the method is
 149 // compiled for direct threading.
 150 struct _Jv_LocalVarTableEntry
 151 {
 152   // First PC value at which variable is live
 153   union
 154   {
 155     pc_t pc;
 156     int bytecode_pc;
 157   };
 158
 159   // length of visibility of variable
 160   int length;
 161
 162   // variable name
 163   char *name;
 164
 165   // type description
 166   char *descriptor;
 167
 168   // stack slot number (long and double occupy slot and slot + 1)
 169   int slot;
 170 };
 171
 172 class _Jv_InterpMethod : public _Jv_MethodBase
 173 {
 174   // Breakpoint instruction
 175   static pc_t breakpoint_insn;
 176 #ifdef DIRECT_THREADED
 177   static insn_slot bp_insn_slot;
 178
 179 public:
 180   // Mutex to prevent a data race between threads when rewriting
 181   // instructions.  See interpret-run.cc for an explanation of its use.
 182   static _Jv_Mutex_t rewrite_insn_mutex;
 183
 184   // The count of threads executing this method.
 185   long thread_count;
 186
 187 private:
 188
 189 #else
 190   static unsigned char bp_insn_opcode;
 191 #endif
 192
 193   _Jv_ushort       max_stack;
 194   _Jv_ushort       max_locals;
 195   int              code_length;
 196
 197   _Jv_ushort       exc_count;
 198   bool             is_15;
 199
 200   // Length of the line_table - when this is zero then line_table is NULL.
 201   int line_table_len;
 202   _Jv_LineTableEntry *line_table;
 203
 204   // The local variable table length and the table itself
 205   int local_var_table_len;
 206   _Jv_LocalVarTableEntry *local_var_table;
 207
 208   pc_t prepared;
 209   int number_insn_slots;
 210
 211   unsigned char* bytecode ()
 212   {
 213     return
 214       ((unsigned char*)this)
 215       + ROUND((sizeof (_Jv_InterpMethod)
 216                + exc_count*sizeof (_Jv_InterpException)), 4);
 217   }
 218
 219   _Jv_InterpException * exceptions ()
 220   {
 221     return (_Jv_InterpException*) (this+1);
 222   }
 223
 224   static size_t size (int exc_count, int code_length)
 225   {
 226     return
 227       ROUND ((sizeof (_Jv_InterpMethod)
 228               + (exc_count * sizeof (_Jv_InterpException))), 4)
 229       + code_length;
 230   }
 231
 232   // return the method's invocation pointer (a stub).
 233   void *ncode (jclass);
 234   void compile (const void * const *);
 235
 236 #if FFI_NATIVE_RAW_API
 237 #  define INTERP_FFI_RAW_TYPE ffi_raw
 238 #else
 239 #  define INTERP_FFI_RAW_TYPE ffi_java_raw
 240 #endif
 241
 242   static void run_normal (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*, void*);
 243   static void run_synch_object (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*, void*);
 244   static void run_class (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*, void*);
 245   static void run_synch_class (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*, void*);
 246
 247   static void run_normal_debug (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*, void*);
 248   static void run_synch_object_debug (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*,
 249                                       void*);
 250   static void run_class_debug (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*, void*);
 251   static void run_synch_class_debug (ffi_cif*, void*, INTERP_FFI_RAW_TYPE*,
 252                                      void*);
 253
 254   static void run (void *, INTERP_FFI_RAW_TYPE *, _Jv_InterpMethod *);
 255   static void run_debug (void *, INTERP_FFI_RAW_TYPE *, _Jv_InterpMethod *);
 256
 257
 258
 259   // Returns source file line number for given PC value, or -1 if line
 260   // number info is unavailable.
 261   int get_source_line(pc_t mpc);
 262
 263    public:
 264
 265   // Convenience function for indexing bytecode PC/insn slots in
 266   // line tables for JDWP
 267   jlong insn_index (pc_t pc);
 268
 269   // Helper function used to check if there is a handler for an exception
 270   // present at this code index
 271   jboolean check_handler (pc_t *pc, _Jv_InterpMethod *meth,
 272                      java::lang::Throwable *ex);
 273
 274   /* Get the line table for this method.
 275    * start  is the lowest index in the method
 276    * end    is the  highest index in the method
 277    * line_numbers is an array to hold the list of source line numbers
 278    * code_indices is an array to hold the corresponding list of code indices
 279    */
 280   void get_line_table (jlong& start, jlong& end, jintArray& line_numbers,
 281                        jlongArray& code_indices);
 282
 283   int get_max_locals ()
 284   {
 285     return static_cast<int> (max_locals);
 286   }
 287
 288   /* Get info for a local variable of this method.
 289    * If there is no loca_var_table for this method it will return -1.
 290    * table_slot  indicates which slot in the local_var_table to get, if there is
 291    * no variable at this location it will return 0.
 292    * Otherwise, it will return the number of table slots after the selected
 293    * slot, indexed from 0.
 294    *
 295    * Example: there are 5 slots in the table, you request slot 0 so it will
 296    * return 4.
 297    */
 298   int get_local_var_table (char **name, char **sig, char **generic_sig,
 299                            jlong *startloc, jint *length, jint *slot,
 300                            int table_slot);
 301
 302   /* Installs a break instruction at the given code index. Returns
 303      the pc_t of the breakpoint or NULL if index is invalid. */
 304   pc_t install_break (jlong index);
 305
 306   // Gets the instruction at the given index
 307   pc_t get_insn (jlong index);
 308
 309   /* Writes the given instruction at the given code index. Returns
 310      the insn or NULL if index is invalid. */
 311   pc_t set_insn (jlong index, pc_t insn);
 312
 313   // Is the given location in this method a breakpoint?
 314   bool breakpoint_at (jlong index);
 315
 316 #ifdef DIRECT_THREADED
 317   friend void _Jv_CompileMethod (_Jv_InterpMethod*);
 318 #endif
 319
 320   friend class _Jv_ClassReader;
 321   friend class _Jv_BytecodeVerifier;
 322   friend class _Jv_StackTrace;
 323   friend class _Jv_InterpreterEngine;
 324
 325 #ifdef JV_MARKOBJ_DECL
 326   friend JV_MARKOBJ_DECL;
 327 #endif
 328 };
 329
 330 class _Jv_InterpClass
 331 {
 332   _Jv_MethodBase **interpreted_methods;
 333   _Jv_ushort     *field_initializers;
 334   jstring source_file_name;
 335   _Jv_ClosureList **closures;
 336
 337   friend class _Jv_ClassReader;
 338   friend class _Jv_InterpMethod;
 339   friend class _Jv_StackTrace;
 340   friend class _Jv_InterpreterEngine;
 341
 342   friend void  _Jv_InitField (jobject, jclass, int);
 343 #ifdef JV_MARKOBJ_DECL
 344   friend JV_MARKOBJ_DECL;
 345 #endif
 346
 347   friend _Jv_MethodBase ** _Jv_GetFirstMethod (_Jv_InterpClass *klass);
 348   friend jstring _Jv_GetInterpClassSourceFile (jclass);
 349 };
 350
 351 extern inline _Jv_MethodBase **
 352 _Jv_GetFirstMethod (_Jv_InterpClass *klass)
 353 {
 354   return klass->interpreted_methods;
 355 }
 356
 357 struct _Jv_ResolvedMethod
 358 {
 359   jint            stack_item_count;
 360   jclass          klass;
 361   _Jv_Method*     method;
 362
 363   // a resolved method holds the cif in-line, so that _Jv_MarkObj just needs
 364   // to mark the resolved method to hold on to the cif.  Some memory could be
 365   // saved by keeping a cache of cif's, since many will be the same.
 366   ffi_cif         cif;
 367   ffi_type *      arg_types[0];
 368 };
 369
 370 class _Jv_JNIMethod : public _Jv_MethodBase
 371 {
 372   // The underlying function.  If NULL we have to look for the
 373   // function.
 374   void *function;
 375
 376   // This is the CIF used by the JNI function.
 377   ffi_cif jni_cif;
 378
 379   // These are the argument types used by the JNI function.
 380   ffi_type **jni_arg_types;
 381
 382   // This function is used when making a JNI call from the interpreter.
 383   static void call (ffi_cif *, void *, INTERP_FFI_RAW_TYPE *, void *);
 384
 385   void *ncode (jclass);
 386
 387   friend class _Jv_ClassReader;
 388   friend class _Jv_InterpreterEngine;
 389
 390 #ifdef JV_MARKOBJ_DECL
 391   friend JV_MARKOBJ_DECL;
 392 #endif
 393
 394 public:
 395   // FIXME: this is ugly.
 396   void set_function (void *f)
 397   {
 398     function = f;
 399   }
 400 };
 401
 402 //  The composite call stack as represented by a linked list of frames
 403 class _Jv_Frame
 404 {
 405 public:
 406   java::lang::Thread *thread;
 407
 408   union
 409   {
 410     _Jv_MethodBase *self;
 411     void *meth;
 412     _Jv_Method *proxyMethod;
 413   };
 414
 415   //The full list of frames, JNI and interpreted
 416   _Jv_Frame *next;
 417   _Jv_FrameType frame_type;
 418
 419   _Jv_Frame (_Jv_MethodBase *s, java::lang::Thread *thr, _Jv_FrameType type)
 420   {
 421     self = s;
 422     frame_type = type;
 423     next = (_Jv_Frame *) thr->frame;
 424     thr->frame = (gnu::gcj::RawData *) this;
 425     thread = thr;
 426   }
 427
 428   ~_Jv_Frame ()
 429   {
 430     thread->frame = (gnu::gcj::RawData *) next;
 431   }
 432
 433   int depth ()
 434   {
 435     int depth = 0;
 436     struct _Jv_Frame *f;
 437     for (f = this; f != NULL; f = f->next)
 438       ++depth;
 439
 440     return depth;
 441   }
 442 };
 443
 444 // An interpreted frame in the call stack
 445 class _Jv_InterpFrame : public _Jv_Frame
 446 {
 447 public:
 448
 449   // Keep the purely interpreted list around so as not to break backtraces
 450   _Jv_InterpFrame *next_interp;
 451
 452   union
 453   {
 454     pc_t pc;
 455     jclass proxyClass;
 456   };
 457
 458   // Pointer to the actual pc value.
 459   pc_t *pc_ptr;
 460
 461   //Debug info for local variables.
 462   _Jv_word *locals;
 463   char *locals_type;
 464
 465   // Object pointer for this frame ("this")
 466   jobject obj_ptr;
 467
 468   _Jv_InterpFrame (void *meth, java::lang::Thread *thr, jclass proxyCls = NULL,
 469                    pc_t *pc = NULL,
 470                    _Jv_FrameType frame_type = frame_interpreter)
 471   : _Jv_Frame (reinterpret_cast<_Jv_MethodBase *> (meth), thr,
 472                      frame_type)
 473   {
 474     next_interp = (_Jv_InterpFrame *) thr->interp_frame;
 475     proxyClass = proxyCls;
 476     thr->interp_frame = (gnu::gcj::RawData *) this;
 477     obj_ptr = NULL;
 478     pc_ptr = pc;
 479   }
 480
 481   ~_Jv_InterpFrame ()
 482   {
 483     thread->interp_frame = (gnu::gcj::RawData *) next_interp;
 484   }
 485
 486   jobject get_this_ptr ()
 487   {
 488     return obj_ptr;
 489   }
 490
 491   pc_t get_pc ()
 492   {
 493     pc_t pc;
 494
 495     // If the PC_PTR is NULL, we are not debugging.
 496     if (pc_ptr == NULL)
 497       pc = 0;
 498     else
 499       pc = *pc_ptr - 1;
 500
 501     return pc;
 502   }
 503 };
 504
 505 // A native frame in the call stack really just a placeholder
 506 class _Jv_NativeFrame : public _Jv_Frame
 507 {
 508 public:
 509
 510   _Jv_NativeFrame (_Jv_JNIMethod *s, java::lang::Thread *thr)
 511   : _Jv_Frame (s, thr, frame_native)
 512   {
 513   }
 514 };
 515
 516 #ifdef DIRECT_THREADED
 517 // This class increments and decrements the thread_count field in an
 518 // interpreted method.  On entry to the interpreter a
 519 // ThreadCountAdjuster is created when increments the thread_count in
 520 // the current method and uses the next_interp field in the frame to
 521 // find the previous method and decrement its thread_count.
 522 class ThreadCountAdjuster
 523 {
 524
 525   // A class used to handle the rewrite_insn_mutex while we're
 526   // adjusting the thread_count in a method.  Unlocking the mutex in a
 527   // destructor ensures that it's unlocked even if (for example) a
 528   // segfault occurs in the critical section.
 529   class MutexLock
 530   {
 531   private:
 532     _Jv_Mutex_t *mutex;
 533   public:
 534     MutexLock (_Jv_Mutex_t *m)
 535     {
 536       mutex = m;
 537       _Jv_MutexLock (mutex);
 538     }
 539     ~MutexLock ()
 540     {
 541       _Jv_MutexUnlock (mutex);
 542     }
 543   };
 544
 545   _Jv_InterpMethod *method;
 546   _Jv_InterpMethod *next_method;
 547
 548 public:
 549
 550   ThreadCountAdjuster (_Jv_InterpMethod *m, _Jv_InterpFrame *fr)
 551   {
 552     MutexLock lock (&::_Jv_InterpMethod::rewrite_insn_mutex);
 553
 554     method = m;
 555     next_method = NULL;
 556
 557     _Jv_InterpFrame *next_interp = fr->next_interp;
 558
 559     // Record the fact that we're executing this method and that
 560     // we're no longer executing the method that called us.
 561     method->thread_count++;
 562
 563     if (next_interp && next_interp->frame_type == frame_interpreter)
 564       {
 565         next_method
 566           = reinterpret_cast<_Jv_InterpMethod *> (next_interp->meth);
 567         next_method->thread_count--;
 568       }
 569   }
 570
 571   ~ThreadCountAdjuster ()
 572   {
 573     MutexLock lock (&::_Jv_InterpMethod::rewrite_insn_mutex);
 574
 575     // We're going to return to the method that called us, so bump its
 576     // thread_count and decrement our own.
 577
 578     method->thread_count--;
 579
 580     if (next_method)
 581       next_method->thread_count++;
 582   }
 583 };
 584 #endif // DIRECT_THREADED
 585
 586 #endif /* INTERPRETER */
 587
 588 #endif /* __JAVA_INTERP_H__ */