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 // We need to include gc_priv.h.  However, it tries to include
  27 // config.h if it hasn't already been included.  So we force the
  28 // inclusion of the Boehm config.h.
  29 extern "C"
  30 {
  31 #include <boehm-config.h>
  32 #include <gc_priv.h>
  33 #include <gc_mark.h>
  34
  35   // These aren't declared in any Boehm GC header.
  36   void GC_finalize_all (void);
  37   ptr_t GC_debug_generic_malloc (size_t size, int k, GC_EXTRA_PARAMS);
  38 };
  39
  40 // FIXME: this should probably be defined in some GC header.
  41 #ifdef GC_DEBUG
  42 #  define GC_GENERIC_MALLOC(Size, Type) \
  43     GC_debug_generic_malloc (Size, Type, GC_EXTRAS)
  44 #else
  45 #  define GC_GENERIC_MALLOC(Size, Type) GC_generic_malloc (Size, Type)
  46 #endif
  47
  48 // We must check for plausibility ourselves.
  49 #define MAYBE_MARK(Obj, Top, Limit, Source, Exit)  \
  50       if ((ptr_t) (Obj) >= GC_least_plausible_heap_addr \
  51           && (ptr_t) (Obj) <= GC_greatest_plausible_heap_addr) \
  52         PUSH_CONTENTS (Obj, Top, Limit, Source, Exit)
  53
  54 #define ObjectClass _CL_Q34java4lang6Object
  55 extern java::lang::Class ObjectClass;
  56 #define ClassClass _CL_Q34java4lang5Class
  57 extern java::lang::Class ClassClass;
  58
  59 \f
  60
  61 // Nonzero if this module has been initialized.
  62 static int initialized = 0;
  63
  64 // `kind' index used when allocating Java objects.
  65 static int obj_kind_x;
  66
  67 // `kind' index used when allocating Java arrays.
  68 static int array_kind_x;
  69
  70 // Freelist used for Java objects.
  71 static ptr_t *obj_free_list;
  72
  73 // Freelist used for Java arrays.
  74 static ptr_t *array_free_list;
  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 (! dt)
  92     return mark_stack_ptr;
  93   jclass klass = dt->clas;
  94
  95   // Every object has a sync_info pointer.
  96   word w = (word) obj->sync_info;
  97   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, obj, o1label);
  98   // Mark the object's class.
  99   w = (word) klass;
 100   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, obj, o2label);
 101
 102   if (klass == &ClassClass)
 103     {
 104       jclass c = (jclass) addr;
 105
 106 #if 0
 107       // The next field should probably not be marked, since this is
 108       // only used in the class hash table.  Marking this field
 109       // basically prohibits class unloading. --Kresten
 110       w = (word) c->next;
 111       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c2label);
 112 #endif
 113
 114       w = (word) c->name;
 115       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c3label);
 116       w = (word) c->superclass;
 117       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c4label);
 118       for (int i = 0; i < c->constants.size; ++i)
 119         {
 120           /* FIXME: We could make this more precise by using the tags -KKT */
 121           w = (word) c->constants.data[i].p;
 122           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c5label);
 123         }
 124
 125 #ifdef INTERPRETER
 126       if (_Jv_IsInterpretedClass (c))
 127         {
 128           w = (word) c->constants.tags;
 129           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c5alabel);
 130           w = (word) c->constants.data;
 131           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c5blabel);
 132         }
 133 #endif
 134
 135       // If the class is an array, then the methods field holds a
 136       // pointer to the element class.  If the class is primitive,
 137       // then the methods field holds a pointer to the array class.
 138       w = (word) c->methods;
 139       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c6label);
 140
 141
 142       if (! c->isArray() && ! c->isPrimitive())
 143         {
 144           // Scan each method in the cases where `methods' really
 145           // points to a methods structure.
 146           for (int i = 0; i < c->method_count; ++i)
 147             {
 148               w = (word) c->methods[i].name;
 149               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c,
 150                              cm1label);
 151               w = (word) c->methods[i].signature;
 152               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c,
 153                              cm2label);
 154
 155               // FIXME: `ncode' entry?
 156
 157 #ifdef INTERPRETER
 158               // The interpreter installs a heap-allocated
 159               // trampoline here, so we'll mark it.
 160               if (_Jv_IsInterpretedClass (c))
 161                   {
 162                       w = (word) c->methods[i].ncode;
 163                       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c,
 164                                   cm3label);
 165                   }
 166 #endif
 167             }
 168         }
 169
 170       // Mark all the fields.
 171       w = (word) c->fields;
 172       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8label);
 173       for (int i = 0; i < c->field_count; ++i)
 174         {
 175           _Jv_Field* field = &c->fields[i];
 176
 177 #ifndef COMPACT_FIELDS
 178           w = (word) field->name;
 179           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8alabel);
 180 #endif
 181           w = (word) field->type;
 182           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8blabel);
 183
 184           // For the interpreter, we also need to mark the memory
 185           // containing static members
 186           if (field->flags & 0x0008)
 187             {
 188               w = (word) field->u.addr;
 189               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c8clabel);
 190
 191               // also, if the static member is a reference,
 192               // mark also the value pointed to.  We check for isResolved
 193               // since marking can happen before memory is allocated for
 194               // static members.
 195               if (JvFieldIsRef (field) && field->isResolved())
 196                 {
 197                   jobject val = *(jobject*) field->u.addr;
 198                   w = (word) val;
 199                   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit,
 200                               c, c8elabel);
 201                 }
 202             }
 203         }
 204
 205       w = (word) c->vtable;
 206       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, c9label);
 207       w = (word) c->interfaces;
 208       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, cAlabel);
 209       for (int i = 0; i < c->interface_count; ++i)
 210         {
 211           w = (word) c->interfaces[i];
 212           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, cClabel);
 213         }
 214       w = (word) c->loader;
 215       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, c, cBlabel);
 216
 217 #ifdef INTERPRETER
 218       if (_Jv_IsInterpretedClass (c))
 219         {
 220           _Jv_InterpClass* ic = (_Jv_InterpClass*)c;
 221
 222           w = (word) ic->interpreted_methods;
 223           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, ic, cElabel);
 224
 225           for (int i = 0; i < c->method_count; i++)
 226             {
 227               w = (word) ic->interpreted_methods[i];
 228               MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, ic, \
 229                           cFlabel);
 230             }
 231
 232           w = (word) ic->field_initializers;
 233           MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, ic, cGlabel);
 234
 235         }
 236 #endif
 237
 238     }
 239   else
 240     {
 241       // NOTE: each class only holds information about the class
 242       // itself.  So we must do the marking for the entire inheritance
 243       // tree in order to mark all fields.  FIXME: what about
 244       // interfaces?  We skip Object here, because Object only has a
 245       // sync_info, and we handled that earlier.
 246       // Note: occasionally `klass' can be null.  For instance, this
 247       // can happen if a GC occurs between the point where an object
 248       // is allocated and where the vtbl slot is set.
 249       while (klass && klass != &ObjectClass)
 250         {
 251           jfieldID field = JvGetFirstInstanceField (klass);
 252           jint max = JvNumInstanceFields (klass);
 253
 254           for (int i = 0; i < max; ++i)
 255             {
 256               if (JvFieldIsRef (field))
 257                 {
 258                   jobject val = JvGetObjectField (obj, field);
 259                   w = (word) val;
 260                   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit,
 261                               obj, elabel);
 262                 }
 263               field = field->getNextInstanceField ();
 264             }
 265           klass = klass->getSuperclass();
 266         }
 267     }
 268
 269   return mark_stack_ptr;
 270 }
 271
 272 // This is called by the GC during the mark phase.  It marks a Java
 273 // array (of objects).  We use `void *' arguments and return, and not
 274 // what the Boehm GC wants, to avoid pollution in our headers.
 275 void *
 276 _Jv_MarkArray (void *addr, void *msp, void *msl, void * /*env*/)
 277 {
 278   mse *mark_stack_ptr = (mse *) msp;
 279   mse *mark_stack_limit = (mse *) msl;
 280   jobjectArray array = (jobjectArray) addr;
 281
 282   _Jv_VTable *dt = *(_Jv_VTable **) addr;
 283   // We check this in case a GC occurs before the vtbl is set.  FIXME:
 284   // should use allocation lock while initializing object.
 285   if (! dt)
 286     return mark_stack_ptr;
 287   jclass klass = dt->clas;
 288
 289   // Every object has a sync_info pointer.
 290   word w = (word) array->sync_info;
 291   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, array, e1label);
 292   // Mark the object's class.
 293   w = (word) klass;
 294   MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, obj, o2label);
 295
 296   for (int i = 0; i < JvGetArrayLength (array); ++i)
 297     {
 298       jobject obj = elements (array)[i];
 299       w = (word) obj;
 300       MAYBE_MARK (w, mark_stack_ptr, mark_stack_limit, array, e2label);
 301     }
 302
 303   return mark_stack_ptr;
 304 }
 305
 306 // Allocate space for a new Java object.  FIXME: this might be the
 307 // wrong interface; we might prefer to pass in the object type as
 308 // well.  It isn't important for this collector, but it might be for
 309 // other collectors.
 310 void *
 311 _Jv_AllocObj (jsize size)
 312 {
 313   return GC_GENERIC_MALLOC (size, obj_kind_x);
 314 }
 315
 316 // Allocate space for a new Java array.  FIXME: again, this might be
 317 // the wrong interface.
 318 void *
 319 _Jv_AllocArray (jsize size)
 320 {
 321   return GC_GENERIC_MALLOC (size, array_kind_x);
 322 }
 323
 324 // Allocate some space that is known to be pointer-free.
 325 void *
 326 _Jv_AllocBytes (jsize size)
 327 {
 328   return GC_GENERIC_MALLOC (size, PTRFREE);
 329 }
 330
 331 static void
 332 call_finalizer (GC_PTR obj, GC_PTR client_data)
 333 {
 334   _Jv_FinalizerFunc *fn = (_Jv_FinalizerFunc *) client_data;
 335   jobject jobj = (jobject) obj;
 336
 337   (*fn) (jobj);
 338 }
 339
 340 void
 341 _Jv_RegisterFinalizer (void *object, _Jv_FinalizerFunc *meth)
 342 {
 343   GC_REGISTER_FINALIZER_NO_ORDER (object, call_finalizer, (GC_PTR) meth,
 344                                   NULL, NULL);
 345 }
 346
 347 void
 348 _Jv_RunFinalizers (void)
 349 {
 350   GC_invoke_finalizers ();
 351 }
 352
 353 void
 354 _Jv_RunAllFinalizers (void)
 355 {
 356   GC_finalize_all ();
 357 }
 358
 359 void
 360 _Jv_RunGC (void)
 361 {
 362   GC_gcollect ();
 363 }
 364
 365 long
 366 _Jv_GCTotalMemory (void)
 367 {
 368   return GC_get_heap_size ();
 369 }
 370
 371 /* Sum size of each hblk.  */
 372 static void
 373 sum_blocks (struct hblk *h, word arg)
 374 {
 375   long *sump = (long *) arg;
 376   /* This evil computation is from boehm-gc/checksums.c.  */
 377   hdr *hhdr = HDR (h);
 378   int bytes = WORDS_TO_BYTES (hhdr->hb_sz);
 379   bytes += HDR_BYTES + HBLKSIZE - 1;
 380   bytes &= ~ (HBLKSIZE - 1);
 381   *sump += bytes;
 382 }
 383
 384 /* This turns out to be expensive to implement.  For now, we don't
 385    care.  We could make it less expensive, perhaps, but that would
 386    require some changes to the collector.  */
 387 long
 388 _Jv_GCFreeMemory (void)
 389 {
 390   long sum = 0;
 391   GC_apply_to_all_blocks (sum_blocks, &sum);
 392   return sum;
 393 }
 394
 395 void
 396 _Jv_InitGC (void)
 397 {
 398   int proc;
 399   DCL_LOCK_STATE;
 400
 401   DISABLE_SIGNALS ();
 402   LOCK ();
 403
 404   if (initialized)
 405     {
 406       UNLOCK ();
 407       ENABLE_SIGNALS ();
 408       return;
 409     }
 410   initialized = 1;
 411
 412   // Set up state for marking and allocation of Java objects.
 413   obj_free_list = (ptr_t *) GC_generic_malloc_inner ((MAXOBJSZ + 1)
 414                                                      * sizeof (ptr_t),
 415                                                      PTRFREE);
 416   memset (obj_free_list, 0, (MAXOBJSZ + 1) * sizeof (ptr_t));
 417
 418   proc = GC_n_mark_procs++;
 419   GC_mark_procs[proc] = (mark_proc) _Jv_MarkObj;
 420
 421   obj_kind_x = GC_n_kinds++;
 422   GC_obj_kinds[obj_kind_x].ok_freelist = obj_free_list;
 423   GC_obj_kinds[obj_kind_x].ok_reclaim_list = 0;
 424   GC_obj_kinds[obj_kind_x].ok_descriptor = MAKE_PROC (proc, 0);
 425   GC_obj_kinds[obj_kind_x].ok_relocate_descr = FALSE;
 426   GC_obj_kinds[obj_kind_x].ok_init = TRUE;
 427
 428   // Set up state for marking and allocation of arrays of Java
 429   // objects.
 430   array_free_list = (ptr_t *) GC_generic_malloc_inner ((MAXOBJSZ + 1)
 431                                                        * sizeof (ptr_t),
 432                                                        PTRFREE);
 433   memset (array_free_list, 0, (MAXOBJSZ + 1) * sizeof (ptr_t));
 434
 435   proc = GC_n_mark_procs++;
 436   GC_mark_procs[proc] = (mark_proc) _Jv_MarkArray;
 437
 438   array_kind_x = GC_n_kinds++;
 439   GC_obj_kinds[array_kind_x].ok_freelist = array_free_list;
 440   GC_obj_kinds[array_kind_x].ok_reclaim_list = 0;
 441   GC_obj_kinds[array_kind_x].ok_descriptor = MAKE_PROC (proc, 0);
 442   GC_obj_kinds[array_kind_x].ok_relocate_descr = FALSE;
 443   GC_obj_kinds[array_kind_x].ok_init = TRUE;
 444
 445   UNLOCK ();
 446   ENABLE_SIGNALS ();
 447 }