libjava/boehm.cc

   1 // boehm.cc - interface between libjava and Boehm GC.
   2
   3 /* Copyright (C) 1998, 1999, 2000  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 #include <config.h>
  12
  13 #include <stdio.h>
  14
  15 #include <jvm.h>
  16 #include <gcj/cni.h>
  17
  18 #include <java/lang/Class.h>
  19 #include <java/lang/reflect/Modifier.h>
  20 #include <java-interp.h>
  21
  22 // More nastiness: the GC wants to define TRUE and FALSE.  We don't
  23 // need the Java definitions (themselves a hack), so we undefine them.
  24 #undef TRUE
  25 #undef FALSE
  26
  27 extern "C"
  28 {
  29 #include <gc_priv.h>
  30 #include <gc_mark.h>
  31
  32   // These aren't declared in any Boehm GC header.
  33   void GC_finalize_all (void);
  34   ptr_t GC_debug_generic_malloc (size_t size, int k, GC_EXTRA_PARAMS);
  35 };
  36
  37 // FIXME: this should probably be defined in some GC header.
  38 #ifdef GC_DEBUG
  39 #  define GC_GENERIC_MALLOC(Size, Type) \
  40     GC_debug_generic_malloc (Size, Type, GC_EXTRAS)
  41 #else
  42 #  define GC_GENERIC_MALLOC(Size, Type) GC_generic_malloc (Size, Type)
  43 #endif
  44
  45 // We must check for plausibility ourselves.
  46 #define MAYBE_MARK(Obj, Top, Limit, Source, Exit)  \
  47       if ((ptr_t) (Obj) >= GC_least_plausible_heap_addr \
  48           && (ptr_t) (Obj) <= GC_greatest_plausible_heap_addr) \
  49         PUSH_CONTENTS (Obj, Top, Limit, Source, Exit)
  50
  51 #define ObjectClass _CL_Q34java4lang6Object
  52 extern java::lang::Class ObjectClass;
  53 #define ClassClass _CL_Q34java4lang5Class
  54 extern java::lang::Class ClassClass;
  55
  56 \f
  57
  58 // Nonzero if this module has been initialized.
  59 static int initialized = 0;
  60
  61 // `kind' index used when allocating Java objects.
  62 static int obj_kind_x;
  63
  64 // `kind' index used when allocating Java arrays.
  65 static int array_kind_x;
  66
  67 // Freelist used for Java objects.
  68 static ptr_t *obj_free_list;
  69
  70 // Freelist used for Java arrays.
  71 static ptr_t *array_free_list;
  72
  73 // Lock used to protect access to Boehm's GC_enable/GC_disable functions.
  74 static _Jv_Mutex_t disable_gc_mutex;
  75
  76 \f
  77
  78 // This is called by the GC during the mark phase.  It marks a Java
  79 // object.  We use `void *' arguments and return, and not what the
  80 // Boehm GC wants, to avoid pollution in our headers.
  81 void *
  82 _Jv_MarkObj (void *addr, void *msp, void *msl, void * /*env*/)
  83 {
  84   mse *mark_stack_ptr = (mse *) msp;
  85   mse *mark_stack_limit = (mse *) msl;
  86   jobject obj = (jobject) addr;
  87
  88   _Jv_VTable *dt = *(_Jv_VTable **) addr;
  89   // We check this in case a GC occurs before the vtbl is set.  FIXME:
  90   // should use allocation lock while initializing object.
  91   if (__builtin_expect (! dt, false))
  92     return mark_stack_ptr;
  93   jclass klass = dt->clas;
  94
  95   // Every object has a sync_info pointer.
  96   ptr_t p = (ptr_t) obj->sync_info;
  97   MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, obj, o1label);
  98   // Mark the object's class.
  99   p = (ptr_t) klass;
 100   MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, obj, o2label);
 101
 102   if (__builtin_expect (klass == &ClassClass, false))
 103     {
 104       jclass c = (jclass) addr;
 105
 106       p = (ptr_t) c->name;
 107       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c3label);
 108       p = (ptr_t) c->superclass;
 109       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c4label);
 110       for (int i = 0; i < c->constants.size; ++i)
 111         {
 112           /* FIXME: We could make this more precise by using the tags -KKT */
 113           p = (ptr_t) c->constants.data[i].p;
 114           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c5label);
 115         }
 116
 117 #ifdef INTERPRETER
 118       if (_Jv_IsInterpretedClass (c))
 119         {
 120           p = (ptr_t) c->constants.tags;
 121           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c5alabel);
 122           p = (ptr_t) c->constants.data;
 123           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c5blabel);
 124         }
 125 #endif
 126
 127       // If the class is an array, then the methods field holds a
 128       // pointer to the element class.  If the class is primitive,
 129       // then the methods field holds a pointer to the array class.
 130       p = (ptr_t) c->methods;
 131       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c6label);
 132
 133
 134       if (! c->isArray() && ! c->isPrimitive())
 135         {
 136           // Scan each method in the cases where `methods' really
 137           // points to a methods structure.
 138           for (int i = 0; i < c->method_count; ++i)
 139             {
 140               p = (ptr_t) c->methods[i].name;
 141               MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c,
 142                              cm1label);
 143               p = (ptr_t) c->methods[i].signature;
 144               MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c,
 145                              cm2label);
 146
 147               // FIXME: `ncode' entry?
 148
 149 #ifdef INTERPRETER
 150               // The interpreter installs a heap-allocated
 151               // trampoline here, so we'll mark it.
 152               if (_Jv_IsInterpretedClass (c))
 153                   {
 154                       p = (ptr_t) c->methods[i].ncode;
 155                       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c,
 156                                   cm3label);
 157                   }
 158 #endif
 159             }
 160         }
 161
 162       // Mark all the fields.
 163       p = (ptr_t) c->fields;
 164       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c8label);
 165       for (int i = 0; i < c->field_count; ++i)
 166         {
 167           _Jv_Field* field = &c->fields[i];
 168
 169 #ifndef COMPACT_FIELDS
 170           p = (ptr_t) field->name;
 171           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c8alabel);
 172 #endif
 173           p = (ptr_t) field->type;
 174           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c8blabel);
 175
 176           // For the interpreter, we also need to mark the memory
 177           // containing static members
 178           if ((field->flags & java::lang::reflect::Modifier::STATIC))
 179             {
 180               p = (ptr_t) field->u.addr;
 181               MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c8clabel);
 182
 183               // also, if the static member is a reference,
 184               // mark also the value pointed to.  We check for isResolved
 185               // since marking can happen before memory is allocated for
 186               // static members.
 187               if (JvFieldIsRef (field) && field->isResolved())
 188                 {
 189                   jobject val = *(jobject*) field->u.addr;
 190                   p = (ptr_t) val;
 191                   MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit,
 192                               c, c8elabel);
 193                 }
 194             }
 195         }
 196
 197       p = (ptr_t) c->vtable;
 198       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, c9label);
 199       p = (ptr_t) c->interfaces;
 200       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, cAlabel);
 201       for (int i = 0; i < c->interface_count; ++i)
 202         {
 203           p = (ptr_t) c->interfaces[i];
 204           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, cClabel);
 205         }
 206       p = (ptr_t) c->loader;
 207       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, c, cBlabel);
 208
 209 #ifdef INTERPRETER
 210       if (_Jv_IsInterpretedClass (c))
 211         {
 212           _Jv_InterpClass* ic = (_Jv_InterpClass*)c;
 213
 214           p = (ptr_t) ic->interpreted_methods;
 215           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, ic, cElabel);
 216
 217           for (int i = 0; i < c->method_count; i++)
 218             {
 219               p = (ptr_t) ic->interpreted_methods[i];
 220               MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, ic, \
 221                           cFlabel);
 222             }
 223
 224           p = (ptr_t) ic->field_initializers;
 225           MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, ic, cGlabel);
 226
 227         }
 228 #endif
 229
 230     }
 231   else
 232     {
 233       // NOTE: each class only holds information about the class
 234       // itself.  So we must do the marking for the entire inheritance
 235       // tree in order to mark all fields.  FIXME: what about
 236       // interfaces?  We skip Object here, because Object only has a
 237       // sync_info, and we handled that earlier.
 238       // Note: occasionally `klass' can be null.  For instance, this
 239       // can happen if a GC occurs between the point where an object
 240       // is allocated and where the vtbl slot is set.
 241       while (klass && klass != &ObjectClass)
 242         {
 243           jfieldID field = JvGetFirstInstanceField (klass);
 244           jint max = JvNumInstanceFields (klass);
 245
 246           for (int i = 0; i < max; ++i)
 247             {
 248               if (JvFieldIsRef (field))
 249                 {
 250                   jobject val = JvGetObjectField (obj, field);
 251                   p = (ptr_t) val;
 252                   MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit,
 253                               obj, elabel);
 254                 }
 255               field = field->getNextField ();
 256             }
 257           klass = klass->getSuperclass();
 258         }
 259     }
 260
 261   return mark_stack_ptr;
 262 }
 263
 264 // This is called by the GC during the mark phase.  It marks a Java
 265 // array (of objects).  We use `void *' arguments and return, and not
 266 // what the Boehm GC wants, to avoid pollution in our headers.
 267 void *
 268 _Jv_MarkArray (void *addr, void *msp, void *msl, void * /*env*/)
 269 {
 270   mse *mark_stack_ptr = (mse *) msp;
 271   mse *mark_stack_limit = (mse *) msl;
 272   jobjectArray array = (jobjectArray) addr;
 273
 274   _Jv_VTable *dt = *(_Jv_VTable **) addr;
 275   // We check this in case a GC occurs before the vtbl is set.  FIXME:
 276   // should use allocation lock while initializing object.
 277   if (__builtin_expect (! dt, false))
 278     return mark_stack_ptr;
 279   jclass klass = dt->clas;
 280
 281   // Every object has a sync_info pointer.
 282   ptr_t p = (ptr_t) array->sync_info;
 283   MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, array, e1label);
 284   // Mark the object's class.
 285   p = (ptr_t) klass;
 286   MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, obj, o2label);
 287
 288   for (int i = 0; i < JvGetArrayLength (array); ++i)
 289     {
 290       jobject obj = elements (array)[i];
 291       p = (ptr_t) obj;
 292       MAYBE_MARK (p, mark_stack_ptr, mark_stack_limit, array, e2label);
 293     }
 294
 295   return mark_stack_ptr;
 296 }
 297
 298 // Allocate space for a new Java object.  FIXME: this might be the
 299 // wrong interface; we might prefer to pass in the object type as
 300 // well.  It isn't important for this collector, but it might be for
 301 // other collectors.
 302 void *
 303 _Jv_AllocObj (jsize size)
 304 {
 305   return GC_GENERIC_MALLOC (size, obj_kind_x);
 306 }
 307
 308 // Allocate space for a new Java array.  FIXME: again, this might be
 309 // the wrong interface.
 310 void *
 311 _Jv_AllocArray (jsize size)
 312 {
 313   return GC_GENERIC_MALLOC (size, array_kind_x);
 314 }
 315
 316 // Allocate some space that is known to be pointer-free.
 317 void *
 318 _Jv_AllocBytes (jsize size)
 319 {
 320   void *r = GC_GENERIC_MALLOC (size, PTRFREE);
 321   // We have to explicitly zero memory here, as the GC doesn't
 322   // guarantee that PTRFREE allocations are zeroed.  Note that we
 323   // don't have to do this for other allocation types because we set
 324   // the `ok_init' flag in the type descriptor.
 325   if (__builtin_expect (r != NULL, !NULL))
 326     memset (r, 0, size);
 327   return r;
 328 }
 329
 330 static void
 331 call_finalizer (GC_PTR obj, GC_PTR client_data)
 332 {
 333   _Jv_FinalizerFunc *fn = (_Jv_FinalizerFunc *) client_data;
 334   jobject jobj = (jobject) obj;
 335
 336   (*fn) (jobj);
 337 }
 338
 339 void
 340 _Jv_RegisterFinalizer (void *object, _Jv_FinalizerFunc *meth)
 341 {
 342   GC_REGISTER_FINALIZER_NO_ORDER (object, call_finalizer, (GC_PTR) meth,
 343                                   NULL, NULL);
 344 }
 345
 346 void
 347 _Jv_RunFinalizers (void)
 348 {
 349   GC_invoke_finalizers ();
 350 }
 351
 352 void
 353 _Jv_RunAllFinalizers (void)
 354 {
 355   GC_finalize_all ();
 356 }
 357
 358 void
 359 _Jv_RunGC (void)
 360 {
 361   GC_gcollect ();
 362 }
 363
 364 long
 365 _Jv_GCTotalMemory (void)
 366 {
 367   return GC_get_heap_size ();
 368 }
 369
 370 long
 371 _Jv_GCFreeMemory (void)
 372 {
 373   return GC_get_free_bytes ();
 374 }
 375
 376 void
 377 _Jv_GCSetInitialHeapSize (size_t size)
 378 {
 379   size_t current = GC_get_heap_size ();
 380   if (size > current)
 381     GC_expand_hp (size - current);
 382 }
 383
 384 void
 385 _Jv_GCSetMaximumHeapSize (size_t size)
 386 {
 387   GC_set_max_heap_size ((GC_word) size);
 388 }
 389
 390 // From boehm's misc.c
 391 extern "C" void GC_enable();
 392 extern "C" void GC_disable();
 393
 394 void
 395 _Jv_DisableGC (void)
 396 {
 397   _Jv_MutexLock (&disable_gc_mutex);
 398   GC_disable();
 399   _Jv_MutexUnlock (&disable_gc_mutex);
 400 }
 401
 402 void
 403 _Jv_EnableGC (void)
 404 {
 405   _Jv_MutexLock (&disable_gc_mutex);
 406   GC_enable();
 407   _Jv_MutexUnlock (&disable_gc_mutex);
 408 }
 409
 410 void
 411 _Jv_InitGC (void)
 412 {
 413   int proc;
 414   DCL_LOCK_STATE;
 415
 416   DISABLE_SIGNALS ();
 417   LOCK ();
 418
 419   if (initialized)
 420     {
 421       UNLOCK ();
 422       ENABLE_SIGNALS ();
 423       return;
 424     }
 425   initialized = 1;
 426
 427   GC_java_finalization = 1;
 428
 429   // Set up state for marking and allocation of Java objects.
 430   obj_free_list = (ptr_t *) GC_generic_malloc_inner ((MAXOBJSZ + 1)
 431                                                      * sizeof (ptr_t),
 432                                                      PTRFREE);
 433   memset (obj_free_list, 0, (MAXOBJSZ + 1) * sizeof (ptr_t));
 434
 435   proc = GC_n_mark_procs++;
 436   GC_mark_procs[proc] = (mark_proc) _Jv_MarkObj;
 437
 438   obj_kind_x = GC_n_kinds++;
 439   GC_obj_kinds[obj_kind_x].ok_freelist = obj_free_list;
 440   GC_obj_kinds[obj_kind_x].ok_reclaim_list = 0;
 441   GC_obj_kinds[obj_kind_x].ok_descriptor = MAKE_PROC (proc, 0);
 442   GC_obj_kinds[obj_kind_x].ok_relocate_descr = FALSE;
 443   GC_obj_kinds[obj_kind_x].ok_init = TRUE;
 444
 445   // Set up state for marking and allocation of arrays of Java
 446   // objects.
 447   array_free_list = (ptr_t *) GC_generic_malloc_inner ((MAXOBJSZ + 1)
 448                                                        * sizeof (ptr_t),
 449                                                        PTRFREE);
 450   memset (array_free_list, 0, (MAXOBJSZ + 1) * sizeof (ptr_t));
 451
 452   proc = GC_n_mark_procs++;
 453   GC_mark_procs[proc] = (mark_proc) _Jv_MarkArray;
 454
 455   array_kind_x = GC_n_kinds++;
 456   GC_obj_kinds[array_kind_x].ok_freelist = array_free_list;
 457   GC_obj_kinds[array_kind_x].ok_reclaim_list = 0;
 458   GC_obj_kinds[array_kind_x].ok_descriptor = MAKE_PROC (proc, 0);
 459   GC_obj_kinds[array_kind_x].ok_relocate_descr = FALSE;
 460   GC_obj_kinds[array_kind_x].ok_init = TRUE;
 461
 462   _Jv_MutexInit (&disable_gc_mutex);
 463
 464   UNLOCK ();
 465   ENABLE_SIGNALS ();
 466 }