libjava/boehm.cc

   1 // boehm.cc - interface between libjava and Boehm GC.
   2
   3 /* Copyright (C) 1998, 1999  Cygnus Solutions
   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-interp.h>
  20
  21 // More nastiness: the GC wants to define TRUE and FALSE.  We don't
  22 // need the Java definitions (themselves a hack), so we undefine them.
  23 #undef TRUE
  24 #undef FALSE
  25
  26 extern "C"
  27 {
  28 #include <gc_priv.h>
  29 #include <gc_mark.h>
  30
  31   // These aren't declared in any Boehm GC header.
  32   void GC_finalize_all (void);
  33   ptr_t GC_debug_generic_malloc (size_t size, int k, GC_EXTRA_PARAMS);
  34 };
  35
  36 // FIXME: this should probably be defined in some GC header.
  37 #ifdef GC_DEBUG
  38 #  define GC_GENERIC_MALLOC(Size, Type) \
  39     GC_debug_generic_malloc (Size, Type, GC_EXTRAS)
  40 #else
  41 #  define GC_GENERIC_MALLOC(Size, Type) GC_generic_malloc (Size, Type)
  42 #endif
  43
  44 // We must check for plausibility ourselves.
  45 #define MAYBE_MARK(Obj, Top, Limit, Source, Exit)  \
  46       if ((ptr_t) (Obj) >= GC_least_plausible_heap_addr \
  47           && (ptr_t) (Obj) <= GC_greatest_plausible_heap_addr) \
  48         PUSH_CONTENTS (Obj, Top, Limit, Source, Exit)
  49
  50 #define ObjectClass _CL_Q34java4lang6Object
  51 extern java::lang::Class ObjectClass;
  52 #define ClassClass _CL_Q34java4lang5Class
  53 extern java::lang::Class ClassClass;
  54
  55 \f
  56
  57 // Nonzero if this module has been initialized.
  58 static int initialized = 0;
  59
  60 // `kind' index used when allocating Java objects.
  61 static int obj_kind_x;
  62
  63 // `kind' index used when allocating Java arrays.
  64 static int array_kind_x;
  65
  66 // Freelist used for Java objects.
  67 static ptr_t *obj_free_list;
  68
  69 // Freelist used for Java arrays.
  70 static ptr_t *array_free_list;
  71
  72 \f
  73
  74 // This is called by the GC during the mark phase.  It marks a Java
  75 // object.  We use `void *' arguments and return, and not what the
  76 // Boehm GC wants, to avoid pollution in our headers.
  77 void *
  78 _Jv_MarkObj (void *addr, void *msp, void *msl, void * /*env*/)
  79 {
  80   mse *mark_stack_ptr = (mse *) msp;
  81   mse *mark_stack_limit = (mse *) msl;
  82   jobject obj = (jobject) addr;
  83
  84   _Jv_VTable *dt = *(_Jv_VTable **) addr;
  85   // We check this in case a GC occurs before the vtbl is set.  FIXME:
  86   // should use allocation lock while initializing object.
  87   if (! dt)
  88     return mark_stack_ptr;
  89   jclass klass = dt->clas;
  90
  91   // Every object has a sync_info pointer.
  92   word w = (word) obj->sync_info;
  93   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, obj, o1label);
  94   // Mark the object's class.
  95   w = (word) klass;
  96   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, obj, o2label);
  97
  98   if (klass == &ClassClass)
  99     {
 100       jclass c = (jclass) addr;
 101
 102 #if 0
 103       // The next field should probably not be marked, since this is
 104       // only used in the class hash table.  Marking this field
 105       // basically prohibits class unloading. --Kresten
 106       w = (word) c->next;
 107       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c2label);
 108 #endif
 109
 110       w = (word) c->name;
 111       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c3label);
 112       w = (word) c->superclass;
 113       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c4label);
 114       for (int i = 0; i < c->constants.size; ++i)
 115         {
 116           /* FIXME: We could make this more precise by using the tags -KKT */
 117           w = (word) c->constants.data[i].p;
 118           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c5label);
 119         }
 120
 121 #ifdef INTERPRETER
 122       if (_Jv_IsInterpretedClass (c))
 123         {
 124           w = (word) c->constants.tags;
 125           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c5alabel);
 126           w = (word) c->constants.data;
 127           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c5blabel);
 128         }
 129 #endif
 130
 131       // If the class is an array, then the methods field holds a
 132       // pointer to the element class.  If the class is primitive,
 133       // then the methods field holds a pointer to the array class.
 134       w = (word) c->methods;
 135       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c6label);
 136
 137
 138       if (! c->isArray() && ! c->isPrimitive())
 139         {
 140           // Scan each method in the cases where `methods' really
 141           // points to a methods structure.
 142           for (int i = 0; i < c->method_count; ++i)
 143             {
 144               w = (word) c->methods[i].name;
 145               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c,
 146                              cm1label);
 147               w = (word) c->methods[i].signature;
 148               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c,
 149                              cm2label);
 150
 151               // FIXME: `ncode' entry?
 152
 153 #ifdef INTERPRETER
 154               // The interpreter installs a heap-allocated
 155               // trampoline here, so we'll mark it.
 156               if (_Jv_IsInterpretedClass (c))
 157                   {
 158                       w = (word) c->methods[i].ncode;
 159                       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c,
 160                                   cm3label);
 161                   }
 162 #endif
 163             }
 164         }
 165
 166       // Mark all the fields.
 167       w = (word) c->fields;
 168       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8label);
 169       for (int i = 0; i < c->field_count; ++i)
 170         {
 171           _Jv_Field* field = &c->fields[i];
 172
 173 #ifndef COMPACT_FIELDS
 174           w = (word) field->name;
 175           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8alabel);
 176 #endif
 177           w = (word) field->type;
 178           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8blabel);
 179
 180           // For the interpreter, we also need to mark the memory
 181           // containing static members
 182           if (field->flags & 0x0008)
 183             {
 184               w = (word) field->u.addr;
 185               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8clabel);
 186
 187               // also, if the static member is a reference,
 188               // mark also the value pointed to.  We check for isResolved
 189               // since marking can happen before memory is allocated for
 190               // static members.
 191               if (JvFieldIsRef (field) && field->isResolved())
 192                 {
 193                   jobject val = *(jobject*) field->u.addr;
 194                   w = (word) val;
 195                   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit,
 196                               c, c8elabel);
 197                 }
 198             }
 199         }
 200
 201       w = (word) c->vtable;
 202       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c9label);
 203       w = (word) c->interfaces;
 204       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, cAlabel);
 205       for (int i = 0; i < c->interface_count; ++i)
 206         {
 207           w = (word) c->interfaces[i];
 208           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, cClabel);
 209         }
 210       w = (word) c->loader;
 211       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, cBlabel);
 212
 213 #ifdef INTERPRETER
 214       if (_Jv_IsInterpretedClass (c))
 215         {
 216           _Jv_InterpClass* ic = (_Jv_InterpClass*)c;
 217
 218           w = (word) ic->interpreted_methods;
 219           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, ic, cElabel);
 220
 221           for (int i = 0; i < c->method_count; i++)
 222             {
 223               w = (word) ic->interpreted_methods[i];
 224               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, ic, \
 225                           cFlabel);
 226             }
 227
 228           w = (word) ic->field_initializers;
 229           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, ic, cGlabel);
 230
 231         }
 232 #endif
 233
 234     }
 235   else
 236     {
 237       // NOTE: each class only holds information about the class
 238       // itself.  So we must do the marking for the entire inheritance
 239       // tree in order to mark all fields.  FIXME: what about
 240       // interfaces?  We skip Object here, because Object only has a
 241       // sync_info, and we handled that earlier.
 242       // Note: occasionally `klass' can be null.  For instance, this
 243       // can happen if a GC occurs between the point where an object
 244       // is allocated and where the vtbl slot is set.
 245       while (klass && klass != &ObjectClass)
 246         {
 247           jfieldID field = JvGetFirstInstanceField (klass);
 248           jint max = JvNumInstanceFields (klass);
 249
 250           for (int i = 0; i < max; ++i)
 251             {
 252               if (JvFieldIsRef (field))
 253                 {
 254                   jobject val = JvGetObjectField (obj, field);
 255                   w = (word) val;
 256                   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit,
 257                               obj, elabel);
 258                 }
 259               field = field->getNextInstanceField ();
 260             }
 261           klass = klass->getSuperclass();
 262         }
 263     }
 264
 265   return mark_stack_ptr;
 266 }
 267
 268 // This is called by the GC during the mark phase.  It marks a Java
 269 // array (of objects).  We use `void *' arguments and return, and not
 270 // what the Boehm GC wants, to avoid pollution in our headers.
 271 void *
 272 _Jv_MarkArray (void *addr, void *msp, void *msl, void * /*env*/)
 273 {
 274   mse *mark_stack_ptr = (mse *) msp;
 275   mse *mark_stack_limit = (mse *) msl;
 276   jobjectArray array = (jobjectArray) addr;
 277
 278   _Jv_VTable *dt = *(_Jv_VTable **) addr;
 279   // We check this in case a GC occurs before the vtbl is set.  FIXME:
 280   // should use allocation lock while initializing object.
 281   if (! dt)
 282     return mark_stack_ptr;
 283   jclass klass = dt->clas;
 284
 285   // Every object has a sync_info pointer.
 286   word w = (word) array->sync_info;
 287   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, array, e1label);
 288   // Mark the object's class.
 289   w = (word) klass;
 290   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, obj, o2label);
 291
 292   for (int i = 0; i < JvGetArrayLength (array); ++i)
 293     {
 294       jobject obj = elements (array)[i];
 295       w = (word) obj;
 296       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, array, e2label);
 297     }
 298
 299   return mark_stack_ptr;
 300 }
 301
 302 // Allocate space for a new Java object.  FIXME: this might be the
 303 // wrong interface; we might prefer to pass in the object type as
 304 // well.  It isn't important for this collector, but it might be for
 305 // other collectors.
 306 void *
 307 _Jv_AllocObj (jsize size)
 308 {
 309   return GC_GENERIC_MALLOC (size, obj_kind_x);
 310 }
 311
 312 // Allocate space for a new Java array.  FIXME: again, this might be
 313 // the wrong interface.
 314 void *
 315 _Jv_AllocArray (jsize size)
 316 {
 317   return GC_GENERIC_MALLOC (size, array_kind_x);
 318 }
 319
 320 // Allocate some space that is known to be pointer-free.
 321 void *
 322 _Jv_AllocBytes (jsize size)
 323 {
 324   return GC_GENERIC_MALLOC (size, PTRFREE);
 325 }
 326
 327 static void
 328 call_finalizer (GC_PTR obj, GC_PTR client_data)
 329 {
 330   _Jv_FinalizerFunc *fn = (_Jv_FinalizerFunc *) client_data;
 331   jobject jobj = (jobject) obj;
 332
 333   (*fn) (jobj);
 334 }
 335
 336 void
 337 _Jv_RegisterFinalizer (void *object, _Jv_FinalizerFunc *meth)
 338 {
 339   GC_REGISTER_FINALIZER_NO_ORDER (object, call_finalizer, (GC_PTR) meth,
 340                                   NULL, NULL);
 341 }
 342
 343 void
 344 _Jv_RunFinalizers (void)
 345 {
 346   GC_invoke_finalizers ();
 347 }
 348
 349 void
 350 _Jv_RunAllFinalizers (void)
 351 {
 352   GC_finalize_all ();
 353 }
 354
 355 void
 356 _Jv_RunGC (void)
 357 {
 358   GC_gcollect ();
 359 }
 360
 361 long
 362 _Jv_GCTotalMemory (void)
 363 {
 364   return GC_get_heap_size ();
 365 }
 366
 367 long
 368 _Jv_GCFreeMemory (void)
 369 {
 370   return GC_get_free_bytes ();
 371 }
 372
 373 void
 374 _Jv_GCSetInitialHeapSize (size_t size)
 375 {
 376   size_t current = GC_get_heap_size ();
 377   if (size > current)
 378     GC_expand_hp (size - current);
 379 }
 380
 381 void
 382 _Jv_GCSetMaximumHeapSize (size_t size)
 383 {
 384   GC_set_max_heap_size ((GC_word) size);
 385 }
 386
 387 void
 388 _Jv_InitGC (void)
 389 {
 390   int proc;
 391   DCL_LOCK_STATE;
 392
 393   DISABLE_SIGNALS ();
 394   LOCK ();
 395
 396   if (initialized)
 397     {
 398       UNLOCK ();
 399       ENABLE_SIGNALS ();
 400       return;
 401     }
 402   initialized = 1;
 403
 404   GC_java_finalization = 1;
 405
 406   // Set up state for marking and allocation of Java objects.
 407   obj_free_list = (ptr_t *) GC_generic_malloc_inner ((MAXOBJSZ + 1)
 408                                                      * sizeof (ptr_t),
 409                                                      PTRFREE);
 410   memset (obj_free_list, 0, (MAXOBJSZ + 1) * sizeof (ptr_t));
 411
 412   proc = GC_n_mark_procs++;
 413   GC_mark_procs[proc] = (mark_proc) _Jv_MarkObj;
 414
 415   obj_kind_x = GC_n_kinds++;
 416   GC_obj_kinds[obj_kind_x].ok_freelist = obj_free_list;
 417   GC_obj_kinds[obj_kind_x].ok_reclaim_list = 0;
 418   GC_obj_kinds[obj_kind_x].ok_descriptor = MAKE_PROC (proc, 0);
 419   GC_obj_kinds[obj_kind_x].ok_relocate_descr = FALSE;
 420   GC_obj_kinds[obj_kind_x].ok_init = TRUE;
 421
 422   // Set up state for marking and allocation of arrays of Java
 423   // objects.
 424   array_free_list = (ptr_t *) GC_generic_malloc_inner ((MAXOBJSZ + 1)
 425                                                        * sizeof (ptr_t),
 426                                                        PTRFREE);
 427   memset (array_free_list, 0, (MAXOBJSZ + 1) * sizeof (ptr_t));
 428
 429   proc = GC_n_mark_procs++;
 430   GC_mark_procs[proc] = (mark_proc) _Jv_MarkArray;
 431
 432   array_kind_x = GC_n_kinds++;
 433   GC_obj_kinds[array_kind_x].ok_freelist = array_free_list;
 434   GC_obj_kinds[array_kind_x].ok_reclaim_list = 0;
 435   GC_obj_kinds[array_kind_x].ok_descriptor = MAKE_PROC (proc, 0);
 436   GC_obj_kinds[array_kind_x].ok_relocate_descr = FALSE;
 437   GC_obj_kinds[array_kind_x].ok_init = TRUE;
 438
 439   UNLOCK ();
 440   ENABLE_SIGNALS ();
 441 }