gc.c

   1 /**********************************************************************
   2
   3   gc.c -
   4
   5   $Author$
   6   created at: Tue Oct  5 09:44:46 JST 1993
   7
   8   Copyright (C) 1993-2007 Yukihiro Matsumoto
   9   Copyright (C) 2000  Network Applied Communication Laboratory, Inc.
  10   Copyright (C) 2000  Information-technology Promotion Agency, Japan
  11
  12 **********************************************************************/
  13
  14 #include "ruby/ruby.h"
  15 #include "ruby/signal.h"
  16 #include "ruby/st.h"
  17 #include "ruby/node.h"
  18 #include "ruby/re.h"
  19 #include "ruby/io.h"
  20 #include "ruby/util.h"
  21 #include "eval_intern.h"
  22 #include "vm_core.h"
  23 #include "gc.h"
  24 #include <stdio.h>
  25 #include <setjmp.h>
  26 #include <sys/types.h>
  27
  28 #ifdef HAVE_SYS_TIME_H
  29 #include <sys/time.h>
  30 #endif
  31
  32 #ifdef HAVE_SYS_RESOURCE_H
  33 #include <sys/resource.h>
  34 #endif
  35
  36 #if defined _WIN32 || defined __CYGWIN__
  37 #include <windows.h>
  38 #endif
  39
  40 #ifdef HAVE_VALGRIND_MEMCHECK_H
  41 # include <valgrind/memcheck.h>
  42 # ifndef VALGRIND_MAKE_MEM_DEFINED
  43 #  define VALGRIND_MAKE_MEM_DEFINED(p, n) VALGRIND_MAKE_READABLE(p, n)
  44 # endif
  45 # ifndef VALGRIND_MAKE_MEM_UNDEFINED
  46 #  define VALGRIND_MAKE_MEM_UNDEFINED(p, n) VALGRIND_MAKE_WRITABLE(p, n)
  47 # endif
  48 #else
  49 # define VALGRIND_MAKE_MEM_DEFINED(p, n) /* empty */
  50 # define VALGRIND_MAKE_MEM_UNDEFINED(p, n) /* empty */
  51 #endif
  52
  53 int rb_io_fptr_finalize(struct rb_io_t*);
  54
  55 #define rb_setjmp(env) RUBY_SETJMP(env)
  56 #define rb_jmp_buf rb_jmpbuf_t
  57
  58 /* Make alloca work the best possible way.  */
  59 #ifdef __GNUC__
  60 # ifndef atarist
  61 #  ifndef alloca
  62 #   define alloca __builtin_alloca
  63 #  endif
  64 # endif /* atarist */
  65 #else
  66 # ifdef HAVE_ALLOCA_H
  67 #  include <alloca.h>
  68 # else
  69 #  ifdef _AIX
  70  #pragma alloca
  71 #  else
  72 #   ifndef alloca /* predefined by HP cc +Olibcalls */
  73 void *alloca ();
  74 #   endif
  75 #  endif /* AIX */
  76 # endif /* HAVE_ALLOCA_H */
  77 #endif /* __GNUC__ */
  78
  79 #ifndef GC_MALLOC_LIMIT
  80 #if defined(MSDOS) || defined(__human68k__)
  81 #define GC_MALLOC_LIMIT 200000
  82 #else
  83 #define GC_MALLOC_LIMIT 8000000
  84 #endif
  85 #endif
  86
  87 static VALUE nomem_error;
  88
  89 #define MARK_STACK_MAX 1024
  90
  91 int ruby_gc_debug_indent = 0;
  92
  93 #undef GC_DEBUG
  94
  95 #if defined(_MSC_VER) || defined(__BORLANDC__) || defined(__CYGWIN__)
  96 #pragma pack(push, 1) /* magic for reducing sizeof(RVALUE): 24 -> 20 */
  97 #endif
  98
  99 typedef struct RVALUE {
 100     union {
 101         struct {
 102             VALUE flags;                /* always 0 for freed obj */
 103             struct RVALUE *next;
 104         } free;
 105         struct RBasic  basic;
 106         struct RObject object;
 107         struct RClass  klass;
 108         struct RFloat  flonum;
 109         struct RString string;
 110         struct RArray  array;
 111         struct RRegexp regexp;
 112         struct RHash   hash;
 113         struct RData   data;
 114         struct RStruct rstruct;
 115         struct RBignum bignum;
 116         struct RFile   file;
 117         struct RNode   node;
 118         struct RMatch  match;
 119         struct RRational rational;
 120         struct RComplex complex;
 121     } as;
 122 #ifdef GC_DEBUG
 123     char *file;
 124     int   line;
 125 #endif
 126 } RVALUE;
 127
 128 #if defined(_MSC_VER) || defined(__BORLANDC__) || defined(__CYGWIN__)
 129 #pragma pack(pop)
 130 #endif
 131
 132 struct heaps_slot {
 133     void *membase;
 134     RVALUE *slot;
 135     int limit;
 136 };
 137
 138 #define HEAP_MIN_SLOTS 10000
 139 #define FREE_MIN  4096
 140
 141 struct gc_list {
 142     VALUE *varptr;
 143     struct gc_list *next;
 144 };
 145
 146 typedef struct rb_objspace {
 147     struct {
 148         unsigned long limit;
 149         unsigned long increase;
 150     } params;
 151     struct {
 152         size_t increment;
 153         struct heaps_slot *ptr;
 154         size_t length;
 155         size_t used;
 156         RVALUE *freelist;
 157         RVALUE *range[2];
 158         RVALUE *freed;
 159     } heap;
 160     struct {
 161         int dont_gc;
 162         int during_gc;
 163     } flags;
 164     struct {
 165         int need_call;
 166         st_table *table;
 167         RVALUE *deferred;
 168     } final;
 169     struct {
 170         VALUE buffer[MARK_STACK_MAX];
 171         VALUE *ptr;
 172         int overflow;
 173     } markstack;
 174     struct gc_list *global_list;
 175     unsigned int count;
 176 } rb_objspace_t;
 177
 178 #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
 179 #define rb_objspace (*GET_VM()->objspace)
 180 #else
 181 static rb_objspace_t rb_objspace = {{GC_MALLOC_LIMIT}, {HEAP_MIN_SLOTS}};
 182 #endif
 183 #define malloc_limit            objspace->params.limit
 184 #define malloc_increase         objspace->params.increase
 185 #define heap_slots              objspace->heap.slots
 186 #define heaps                   objspace->heap.ptr
 187 #define heaps_length            objspace->heap.length
 188 #define heaps_used              objspace->heap.used
 189 #define freelist                objspace->heap.freelist
 190 #define lomem                   objspace->heap.range[0]
 191 #define himem                   objspace->heap.range[1]
 192 #define heaps_inc               objspace->heap.increment
 193 #define heaps_freed             objspace->heap.freed
 194 #define dont_gc                 objspace->flags.dont_gc
 195 #define during_gc               objspace->flags.during_gc
 196 #define need_call_final         objspace->final.need_call
 197 #define finalizer_table         objspace->final.table
 198 #define deferred_final_list     objspace->final.deferred
 199 #define mark_stack              objspace->markstack.buffer
 200 #define mark_stack_ptr          objspace->markstack.ptr
 201 #define mark_stack_overflow     objspace->markstack.overflow
 202 #define global_List             objspace->global_list
 203
 204 rb_objspace_t *
 205 rb_objspace_alloc(void)
 206 {
 207     rb_objspace_t *objspace = malloc(sizeof(rb_objspace_t));
 208     memset(objspace, 0, sizeof(*objspace));
 209     malloc_limit = GC_MALLOC_LIMIT;
 210
 211     return objspace;
 212 }
 213
 214 /* tiny heap size */
 215 /* 32KB */
 216 /*#define HEAP_SIZE 0x8000 */
 217 /* 128KB */
 218 /*#define HEAP_SIZE 0x20000 */
 219 /* 64KB */
 220 /*#define HEAP_SIZE 0x10000 */
 221 /* 16KB */
 222 #define HEAP_SIZE 0x4000
 223 /* 8KB */
 224 /*#define HEAP_SIZE 0x2000 */
 225 /* 4KB */
 226 /*#define HEAP_SIZE 0x1000 */
 227 /* 2KB */
 228 /*#define HEAP_SIZE 0x800 */
 229
 230 #define HEAP_OBJ_LIMIT (HEAP_SIZE / sizeof(struct RVALUE))
 231 #define FREE_MIN  4096
 232
 233 extern st_table *rb_class_tbl;
 234 VALUE *rb_gc_stack_start = 0;
 235 #ifdef __ia64
 236 VALUE *rb_gc_register_stack_start = 0;
 237 #endif
 238
 239 int ruby_gc_stress = 0;
 240
 241
 242 #ifdef DJGPP
 243 /* set stack size (http://www.delorie.com/djgpp/v2faq/faq15_9.html) */
 244 unsigned int _stklen = 0x180000; /* 1.5 kB */
 245 #endif
 246
 247 #if defined(DJGPP) || defined(_WIN32_WCE)
 248 size_t rb_gc_stack_maxsize = 65535*sizeof(VALUE);
 249 #else
 250 size_t rb_gc_stack_maxsize = 655300*sizeof(VALUE);
 251 #endif
 252
 253 static void run_final(rb_objspace_t *objspace, VALUE obj);
 254 static int garbage_collect(rb_objspace_t *objspace);
 255
 256 void
 257 rb_global_variable(VALUE *var)
 258 {
 259     rb_gc_register_address(var);
 260 }
 261
 262 void
 263 rb_memerror(void)
 264 {
 265     rb_thread_t *th = GET_THREAD();
 266     if (!nomem_error ||
 267         (rb_thread_raised_p(th, RAISED_NOMEMORY) && rb_safe_level() < 4)) {
 268         fprintf(stderr, "[FATAL] failed to allocate memory\n");
 269         exit(1);
 270     }
 271     rb_thread_raised_set(th, RAISED_NOMEMORY);
 272     rb_exc_raise(nomem_error);
 273 }
 274
 275 /*
 276  *  call-seq:
 277  *    GC.stress                 => true or false
 278  *
 279  *  returns current status of GC stress mode.
 280  */
 281
 282 static VALUE
 283 gc_stress_get(VALUE self)
 284 {
 285     return ruby_gc_stress ? Qtrue : Qfalse;
 286 }
 287
 288 /*
 289  *  call-seq:
 290  *    GC.stress = bool          => bool
 291  *
 292  *  updates GC stress mode.
 293  *
 294  *  When GC.stress = true, GC is invoked for all GC opportunity:
 295  *  all memory and object allocation.
 296  *
 297  *  Since it makes Ruby very slow, it is only for debugging.
 298  */
 299
 300 static VALUE
 301 gc_stress_set(VALUE self, VALUE bool)
 302 {
 303     rb_secure(2);
 304     ruby_gc_stress = RTEST(bool);
 305     return bool;
 306 }
 307
 308 void *
 309 ruby_vm_xmalloc(rb_objspace_t *objspace, size_t size)
 310 {
 311     void *mem;
 312
 313     if (size < 0) {
 314         rb_raise(rb_eNoMemError, "negative allocation size (or too big)");
 315     }
 316     if (size == 0) size = 1;
 317     malloc_increase += size;
 318
 319     if (ruby_gc_stress || malloc_increase > malloc_limit) {
 320         garbage_collect(objspace);
 321     }
 322     RUBY_CRITICAL(mem = malloc(size));
 323     if (!mem) {
 324         if (garbage_collect(objspace)) {
 325             RUBY_CRITICAL(mem = malloc(size));
 326         }
 327         if (!mem) {
 328             rb_memerror();
 329         }
 330     }
 331
 332     return mem;
 333 }
 334
 335 void *
 336 ruby_xmalloc(size_t size)
 337 {
 338     return ruby_vm_xmalloc(&rb_objspace, size);
 339 }
 340
 341 void *
 342 ruby_vm_xmalloc2(rb_objspace_t *objspace, size_t n, size_t size)
 343 {
 344     size_t len = size * n;
 345     if (n != 0 && size != len / n) {
 346         rb_raise(rb_eArgError, "malloc: possible integer overflow");
 347     }
 348     return ruby_vm_xmalloc(objspace, len);
 349 }
 350
 351 void *
 352 ruby_xmalloc2(size_t n, size_t size)
 353 {
 354     return ruby_vm_xmalloc2(&rb_objspace, n, size);
 355 }
 356
 357 void *
 358 ruby_vm_xcalloc(rb_objspace_t *objspace, size_t n, size_t size)
 359 {
 360     void *mem;
 361
 362     mem = ruby_vm_xmalloc2(objspace, n, size);
 363     memset(mem, 0, n * size);
 364
 365     return mem;
 366 }
 367
 368 void *
 369 ruby_xcalloc(size_t n, size_t size)
 370 {
 371     return ruby_vm_xcalloc(&rb_objspace, n, size);
 372 }
 373
 374 void *
 375 ruby_vm_xrealloc(rb_objspace_t *objspace, void *ptr, size_t size)
 376 {
 377     void *mem;
 378
 379     if (size < 0) {
 380         rb_raise(rb_eArgError, "negative re-allocation size");
 381     }
 382     if (!ptr) return ruby_xmalloc(size);
 383     if (size == 0) size = 1;
 384     malloc_increase += size;
 385     if (ruby_gc_stress) garbage_collect(objspace);
 386     RUBY_CRITICAL(mem = realloc(ptr, size));
 387     if (!mem) {
 388         if (garbage_collect(objspace)) {
 389             RUBY_CRITICAL(mem = realloc(ptr, size));
 390         }
 391         if (!mem) {
 392             rb_memerror();
 393         }
 394     }
 395
 396     return mem;
 397 }
 398
 399 void *
 400 ruby_xrealloc(void *ptr, size_t size)
 401 {
 402     return ruby_vm_xrealloc(&rb_objspace, ptr, size);
 403 }
 404
 405 void *
 406 ruby_vm_xrealloc2(rb_objspace_t *objspace, void *ptr, size_t n, size_t size)
 407 {
 408     size_t len = size * n;
 409     if (n != 0 && size != len / n) {
 410         rb_raise(rb_eArgError, "realloc: possible integer overflow");
 411     }
 412     return ruby_vm_xrealloc(objspace, ptr, len);
 413 }
 414
 415 void *
 416 ruby_xrealloc2(void *ptr, size_t n, size_t size)
 417 {
 418     return ruby_vm_xrealloc2(&rb_objspace, ptr, n, size);
 419 }
 420
 421 void
 422 ruby_xfree(void *x)
 423 {
 424     if (x)
 425         RUBY_CRITICAL(free(x));
 426 }
 427
 428
 429 /*
 430  *  call-seq:
 431  *     GC.enable    => true or false
 432  *
 433  *  Enables garbage collection, returning <code>true</code> if garbage
 434  *  collection was previously disabled.
 435  *
 436  *     GC.disable   #=> false
 437  *     GC.enable    #=> true
 438  *     GC.enable    #=> false
 439  *
 440  */
 441
 442 VALUE
 443 rb_gc_enable(void)
 444 {
 445     rb_objspace_t *objspace = &rb_objspace;
 446     int old = dont_gc;
 447
 448     dont_gc = Qfalse;
 449     return old;
 450 }
 451
 452 /*
 453  *  call-seq:
 454  *     GC.disable    => true or false
 455  *
 456  *  Disables garbage collection, returning <code>true</code> if garbage
 457  *  collection was already disabled.
 458  *
 459  *     GC.disable   #=> false
 460  *     GC.disable   #=> true
 461  *
 462  */
 463
 464 VALUE
 465 rb_gc_disable(void)
 466 {
 467     rb_objspace_t *objspace = &rb_objspace;
 468     int old = dont_gc;
 469
 470     dont_gc = Qtrue;
 471     return old;
 472 }
 473
 474 VALUE rb_mGC;
 475
 476 void
 477 rb_gc_register_address(VALUE *addr)
 478 {
 479     rb_objspace_t *objspace = &rb_objspace;
 480     struct gc_list *tmp;
 481
 482     tmp = ALLOC(struct gc_list);
 483     tmp->next = global_List;
 484     tmp->varptr = addr;
 485     global_List = tmp;
 486 }
 487
 488 void
 489 rb_register_mark_object(VALUE obj)
 490 {
 491     VALUE ary = GET_THREAD()->vm->mark_object_ary;
 492     rb_ary_push(ary, obj);
 493 }
 494
 495 void
 496 rb_gc_unregister_address(VALUE *addr)
 497 {
 498     rb_objspace_t *objspace = &rb_objspace;
 499     struct gc_list *tmp = global_List;
 500
 501     if (tmp->varptr == addr) {
 502         global_List = tmp->next;
 503         RUBY_CRITICAL(free(tmp));
 504         return;
 505     }
 506     while (tmp->next) {
 507         if (tmp->next->varptr == addr) {
 508             struct gc_list *t = tmp->next;
 509
 510             tmp->next = tmp->next->next;
 511             RUBY_CRITICAL(free(t));
 512             break;
 513         }
 514         tmp = tmp->next;
 515     }
 516 }
 517
 518
 519 static void
 520 allocate_heaps(rb_objspace_t *objspace, size_t next_heaps_length)
 521 {
 522     struct heaps_slot *p;
 523     size_t size;
 524
 525     size = next_heaps_length*sizeof(struct heaps_slot);
 526     RUBY_CRITICAL(
 527                   if (heaps_used > 0) {
 528                       p = (struct heaps_slot *)realloc(heaps, size);
 529                       if (p) heaps = p;
 530                   }
 531                   else {
 532                       p = heaps = (struct heaps_slot *)malloc(size);
 533                   }
 534                   );
 535     if (p == 0) rb_memerror();
 536     heaps_length = next_heaps_length;
 537 }
 538
 539 static void
 540 assign_heap_slot(rb_objspace_t *objspace)
 541 {
 542     RVALUE *p, *pend, *membase;
 543     size_t hi, lo, mid;
 544     int objs;
 545
 546     objs = HEAP_OBJ_LIMIT;
 547     RUBY_CRITICAL(p = (RVALUE*)malloc(HEAP_SIZE));
 548     if (p == 0)
 549         rb_memerror();
 550
 551     membase = p;
 552     if ((VALUE)p % sizeof(RVALUE) != 0) {
 553         p = (RVALUE*)((VALUE)p + sizeof(RVALUE) - ((VALUE)p % sizeof(RVALUE)));
 554         if ((HEAP_SIZE - HEAP_OBJ_LIMIT * sizeof(RVALUE)) < ((char*)p - (char*)membase)) {
 555             objs--;
 556         }
 557     }
 558
 559
 560     lo = 0;
 561     hi = heaps_used;
 562     while (lo < hi) {
 563         register RVALUE *mid_membase;
 564         mid = (lo + hi) / 2;
 565         mid_membase = heaps[mid].membase;
 566         if (mid_membase < membase) {
 567             lo = mid + 1;
 568         }
 569         else if (mid_membase > membase) {
 570             hi = mid;
 571         }
 572         else {
 573             rb_bug("same heap slot is allocated: %p at %ld", membase, mid);
 574         }
 575     }
 576     if (hi < heaps_used) {
 577         MEMMOVE(&heaps[hi+1], &heaps[hi], struct heaps_slot, heaps_used - hi);
 578     }
 579     heaps[hi].membase = membase;
 580     heaps[hi].slot = p;
 581     heaps[hi].limit = objs;
 582     pend = p + objs;
 583     if (lomem == 0 || lomem > p) lomem = p;
 584     if (himem < pend) himem = pend;
 585     heaps_used++;
 586
 587     while (p < pend) {
 588         p->as.free.flags = 0;
 589         p->as.free.next = freelist;
 590         freelist = p;
 591         p++;
 592     }
 593 }
 594
 595 static void
 596 init_heap(rb_objspace_t *objspace)
 597 {
 598     size_t add, i;
 599
 600     add = HEAP_MIN_SLOTS / HEAP_OBJ_LIMIT;
 601
 602     if ((heaps_used + add) > heaps_length) {
 603         allocate_heaps(objspace, heaps_used + add);
 604     }
 605
 606     for (i = 0; i < add; i++) {
 607         assign_heap_slot(objspace);
 608     }
 609     heaps_inc = 0;
 610 }
 611
 612
 613 static void
 614 set_heaps_increment(rb_objspace_t *objspace)
 615 {
 616     size_t next_heaps_length = heaps_used * 1.8;
 617     heaps_inc = next_heaps_length - heaps_used;
 618
 619     if (next_heaps_length > heaps_length) {
 620         allocate_heaps(objspace, next_heaps_length);
 621     }
 622 }
 623
 624 static int
 625 heaps_increment(rb_objspace_t *objspace)
 626 {
 627     if (heaps_inc > 0) {
 628         assign_heap_slot(objspace);
 629         heaps_inc--;
 630         return Qtrue;
 631     }
 632     return Qfalse;
 633 }
 634
 635 #define RANY(o) ((RVALUE*)(o))
 636
 637 static VALUE
 638 rb_newobj_from_heap(rb_objspace_t *objspace)
 639 {
 640     VALUE obj;
 641
 642     if (ruby_gc_stress || !freelist) {
 643         if (!heaps_increment(objspace) && !garbage_collect(objspace)) {
 644             rb_memerror();
 645         }
 646     }
 647
 648     obj = (VALUE)freelist;
 649     freelist = freelist->as.free.next;
 650
 651     MEMZERO((void*)obj, RVALUE, 1);
 652 #ifdef GC_DEBUG
 653     RANY(obj)->file = rb_sourcefile();
 654     RANY(obj)->line = rb_sourceline();
 655 #endif
 656
 657     return obj;
 658 }
 659
 660 #if USE_VALUE_CACHE
 661 static VALUE
 662 rb_fill_value_cache(rb_thread_t *th)
 663 {
 664     rb_objspace_t *objspace = &rb_objspace;
 665     int i;
 666     VALUE rv;
 667
 668     /* LOCK */
 669     for (i=0; i<RUBY_VM_VALUE_CACHE_SIZE; i++) {
 670         VALUE v = rb_newobj_from_heap(objspace);
 671
 672         th->value_cache[i] = v;
 673         RBASIC(v)->flags = FL_MARK;
 674     }
 675     th->value_cache_ptr = &th->value_cache[0];
 676     rv = rb_newobj_from_heap(objspace);
 677     /* UNLOCK */
 678     return rv;
 679 }
 680 #endif
 681
 682 VALUE
 683 rb_newobj(void)
 684 {
 685 #if USE_VALUE_CACHE
 686     rb_thread_t *th = GET_THREAD();
 687     VALUE v = *th->value_cache_ptr;
 688 #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
 689     rb_objspace_t *objspace = th->vm->objspace;
 690 #else
 691     rb_objspace_t *objspace = &rb_objspace;
 692 #endif
 693
 694     if (v) {
 695         RBASIC(v)->flags = 0;
 696         th->value_cache_ptr++;
 697     }
 698     else {
 699         v = rb_fill_value_cache(th);
 700     }
 701
 702 #if defined(GC_DEBUG)
 703     printf("cache index: %d, v: %p, th: %p\n",
 704            th->value_cache_ptr - th->value_cache, v, th);
 705 #endif
 706     return v;
 707 #else
 708     rb_objspace_t *objspace = &rb_objspace;
 709     return rb_newobj_from_heap(objspace);
 710 #endif
 711 }
 712
 713 NODE*
 714 rb_node_newnode(enum node_type type, VALUE a0, VALUE a1, VALUE a2)
 715 {
 716     NODE *n = (NODE*)rb_newobj();
 717
 718     n->flags |= T_NODE;
 719     nd_set_type(n, type);
 720
 721     n->u1.value = a0;
 722     n->u2.value = a1;
 723     n->u3.value = a2;
 724
 725     return n;
 726 }
 727
 728 VALUE
 729 rb_data_object_alloc(VALUE klass, void *datap, RUBY_DATA_FUNC dmark, RUBY_DATA_FUNC dfree)
 730 {
 731     NEWOBJ(data, struct RData);
 732     if (klass) Check_Type(klass, T_CLASS);
 733     OBJSETUP(data, klass, T_DATA);
 734     data->data = datap;
 735     data->dfree = dfree;
 736     data->dmark = dmark;
 737
 738     return (VALUE)data;
 739 }
 740
 741 #ifdef __ia64
 742 #define SET_STACK_END (SET_MACHINE_STACK_END(&th->machine_stack_end), th->machine_register_stack_end = rb_ia64_bsp())
 743 #else
 744 #define SET_STACK_END SET_MACHINE_STACK_END(&th->machine_stack_end)
 745 #endif
 746
 747 #define STACK_START (th->machine_stack_start)
 748 #define STACK_END (th->machine_stack_end)
 749 #define STACK_LEVEL_MAX (th->machine_stack_maxsize/sizeof(VALUE))
 750
 751 #if STACK_GROW_DIRECTION < 0
 752 # define STACK_LENGTH  (STACK_START - STACK_END)
 753 #elif STACK_GROW_DIRECTION > 0
 754 # define STACK_LENGTH  (STACK_END - STACK_START + 1)
 755 #else
 756 # define STACK_LENGTH  ((STACK_END < STACK_START) ? STACK_START - STACK_END\
 757                                            : STACK_END - STACK_START + 1)
 758 #endif
 759 #if STACK_GROW_DIRECTION > 0
 760 # define STACK_UPPER(x, a, b) a
 761 #elif STACK_GROW_DIRECTION < 0
 762 # define STACK_UPPER(x, a, b) b
 763 #else
 764 static int grow_direction;
 765 static int
 766 stack_grow_direction(VALUE *addr)
 767 {
 768     rb_thread_t *th = GET_THREAD();
 769     SET_STACK_END;
 770
 771     if (STACK_END > addr) return grow_direction = 1;
 772     return grow_direction = -1;
 773 }
 774 # define stack_growup_p(x) ((grow_direction ? grow_direction : stack_grow_direction(x)) > 0)
 775 # define STACK_UPPER(x, a, b) (stack_growup_p(x) ? a : b)
 776 #endif
 777
 778 #define GC_WATER_MARK 512
 779
 780 int
 781 ruby_stack_length(VALUE **p)
 782 {
 783     rb_thread_t *th = GET_THREAD();
 784     SET_STACK_END;
 785     if (p) *p = STACK_UPPER(STACK_END, STACK_START, STACK_END);
 786     return STACK_LENGTH;
 787 }
 788
 789 int
 790 ruby_stack_check(void)
 791 {
 792     int ret;
 793     rb_thread_t *th = GET_THREAD();
 794     SET_STACK_END;
 795     ret = STACK_LENGTH > STACK_LEVEL_MAX + GC_WATER_MARK;
 796 #ifdef __ia64
 797     if (!ret) {
 798         ret = (VALUE*)rb_ia64_bsp() - th->machine_register_stack_start >
 799               th->machine_register_stack_maxsize/sizeof(VALUE) + GC_WATER_MARK;
 800     }
 801 #endif
 802     return ret;
 803 }
 804
 805 static void
 806 init_mark_stack(rb_objspace_t *objspace)
 807 {
 808     mark_stack_overflow = 0;
 809     mark_stack_ptr = mark_stack;
 810 }
 811
 812 #define MARK_STACK_EMPTY (mark_stack_ptr == mark_stack)
 813
 814 static void gc_mark(rb_objspace_t *objspace, VALUE ptr, int lev);
 815 static void gc_mark_children(rb_objspace_t *objspace, VALUE ptr, int lev);
 816
 817 static void
 818 gc_mark_all(rb_objspace_t *objspace)
 819 {
 820     RVALUE *p, *pend;
 821     size_t i;
 822
 823     init_mark_stack(objspace);
 824     for (i = 0; i < heaps_used; i++) {
 825         p = heaps[i].slot; pend = p + heaps[i].limit;
 826         while (p < pend) {
 827             if ((p->as.basic.flags & FL_MARK) &&
 828                 (p->as.basic.flags != FL_MARK)) {
 829                 gc_mark_children(objspace, (VALUE)p, 0);
 830             }
 831             p++;
 832         }
 833     }
 834 }
 835
 836 static void
 837 gc_mark_rest(rb_objspace_t *objspace)
 838 {
 839     VALUE tmp_arry[MARK_STACK_MAX];
 840     VALUE *p;
 841
 842     p = (mark_stack_ptr - mark_stack) + tmp_arry;
 843     MEMCPY(tmp_arry, mark_stack, VALUE, p - tmp_arry);
 844
 845     init_mark_stack(objspace);
 846     while (p != tmp_arry) {
 847         p--;
 848         gc_mark_children(objspace, *p, 0);
 849     }
 850 }
 851
 852 static inline int
 853 is_pointer_to_heap(rb_objspace_t *objspace, void *ptr)
 854 {
 855     register RVALUE *p = RANY(ptr);
 856     register struct heaps_slot *heap;
 857     register size_t hi, lo, mid;
 858
 859     if (p < lomem || p > himem) return Qfalse;
 860     if ((VALUE)p % sizeof(RVALUE) != 0) return Qfalse;
 861
 862     /* check if p looks like a pointer using bsearch*/
 863     lo = 0;
 864     hi = heaps_used;
 865     while (lo < hi) {
 866         mid = (lo + hi) / 2;
 867         heap = &heaps[mid];
 868         if (heap->slot <= p) {
 869             if (p < heap->slot + heap->limit)
 870                 return Qtrue;
 871             lo = mid + 1;
 872         }
 873         else {
 874             hi = mid;
 875         }
 876     }
 877     return Qfalse;
 878 }
 879
 880 static void
 881 mark_locations_array(rb_objspace_t *objspace, register VALUE *x, register long n)
 882 {
 883     VALUE v;
 884     while (n--) {
 885         v = *x;
 886         VALGRIND_MAKE_MEM_DEFINED(&v, sizeof(v));
 887         if (is_pointer_to_heap(objspace, (void *)v)) {
 888             gc_mark(objspace, v, 0);
 889         }
 890         x++;
 891     }
 892 }
 893
 894 static void
 895 gc_mark_locations(rb_objspace_t *objspace, VALUE *start, VALUE *end)
 896 {
 897     long n;
 898
 899     if (end <= start) return;
 900     n = end - start;
 901     mark_locations_array(&rb_objspace, start,n);
 902 }
 903
 904 void
 905 rb_gc_mark_locations(VALUE *start, VALUE *end)
 906 {
 907     gc_mark_locations(&rb_objspace, start, end);
 908 }
 909
 910 #define rb_gc_mark_locations(start, end) gc_mark_locations(objspace, start, end)
 911
 912 struct mark_tbl_arg {
 913     rb_objspace_t *objspace;
 914     int lev;
 915 };
 916
 917 static int
 918 mark_entry(ID key, VALUE value, st_data_t data)
 919 {
 920     struct mark_tbl_arg *arg = (void*)data;
 921     gc_mark(arg->objspace, value, arg->lev);
 922     return ST_CONTINUE;
 923 }
 924
 925 static void
 926 mark_tbl(rb_objspace_t *objspace, st_table *tbl, int lev)
 927 {
 928     struct mark_tbl_arg arg;
 929     if (!tbl) return;
 930     arg.objspace = objspace;
 931     arg.lev = lev;
 932     st_foreach(tbl, mark_entry, (st_data_t)&arg);
 933 }
 934
 935 void
 936 rb_mark_tbl(st_table *tbl)
 937 {
 938     mark_tbl(&rb_objspace, tbl, 0);
 939 }
 940
 941 static int
 942 mark_key(VALUE key, VALUE value, st_data_t data)
 943 {
 944     struct mark_tbl_arg *arg = (void*)data;
 945     gc_mark(arg->objspace, key, arg->lev);
 946     return ST_CONTINUE;
 947 }
 948
 949 static void
 950 mark_set(rb_objspace_t *objspace, st_table *tbl, int lev)
 951 {
 952     struct mark_tbl_arg arg;
 953     if (!tbl) return;
 954     arg.objspace = objspace;
 955     arg.lev = lev;
 956     st_foreach(tbl, mark_key, (st_data_t)&arg);
 957 }
 958
 959 void
 960 rb_mark_set(st_table *tbl)
 961 {
 962     mark_set(&rb_objspace, tbl, 0);
 963 }
 964
 965 static int
 966 mark_keyvalue(VALUE key, VALUE value, st_data_t data)
 967 {
 968     struct mark_tbl_arg *arg = (void*)data;
 969     gc_mark(arg->objspace, key, arg->lev);
 970     gc_mark(arg->objspace, value, arg->lev);
 971     return ST_CONTINUE;
 972 }
 973
 974 static void
 975 mark_hash(rb_objspace_t *objspace, st_table *tbl, int lev)
 976 {
 977     struct mark_tbl_arg arg;
 978     if (!tbl) return;
 979     arg.objspace = objspace;
 980     arg.lev = lev;
 981     st_foreach(tbl, mark_keyvalue, (st_data_t)&arg);
 982 }
 983
 984 void
 985 rb_mark_hash(st_table *tbl)
 986 {
 987     mark_hash(&rb_objspace, tbl, 0);
 988 }
 989
 990 void
 991 rb_gc_mark_maybe(VALUE obj)
 992 {
 993     if (is_pointer_to_heap(&rb_objspace, (void *)obj)) {
 994         gc_mark(&rb_objspace, obj, 0);
 995     }
 996 }
 997
 998 #define GC_LEVEL_MAX 250
 999
1000 static void
1001 gc_mark(rb_objspace_t *objspace, VALUE ptr, int lev)
1002 {
1003     register RVALUE *obj;
1004
1005     obj = RANY(ptr);
1006     if (rb_special_const_p(ptr)) return; /* special const not marked */
1007     if (obj->as.basic.flags == 0) return;       /* free cell */
1008     if (obj->as.basic.flags & FL_MARK) return;  /* already marked */
1009     obj->as.basic.flags |= FL_MARK;
1010
1011     if (lev > GC_LEVEL_MAX || (lev == 0 && ruby_stack_check())) {
1012         if (!mark_stack_overflow) {
1013             if (mark_stack_ptr - mark_stack < MARK_STACK_MAX) {
1014                 *mark_stack_ptr = ptr;
1015                 mark_stack_ptr++;
1016             }
1017             else {
1018                 mark_stack_overflow = 1;
1019             }
1020         }
1021         return;
1022     }
1023     gc_mark_children(objspace, ptr, lev+1);
1024 }
1025
1026 void
1027 rb_gc_mark(VALUE ptr)
1028 {
1029     gc_mark(&rb_objspace, ptr, 0);
1030 }
1031
1032 static void
1033 gc_mark_children(rb_objspace_t *objspace, VALUE ptr, int lev)
1034 {
1035     register RVALUE *obj = RANY(ptr);
1036
1037     goto marking;               /* skip */
1038
1039   again:
1040     obj = RANY(ptr);
1041     if (rb_special_const_p(ptr)) return; /* special const not marked */
1042     if (obj->as.basic.flags == 0) return;       /* free cell */
1043     if (obj->as.basic.flags & FL_MARK) return;  /* already marked */
1044     obj->as.basic.flags |= FL_MARK;
1045
1046   marking:
1047     if (FL_TEST(obj, FL_EXIVAR)) {
1048         rb_mark_generic_ivar(ptr);
1049     }
1050
1051     switch (obj->as.basic.flags & T_MASK) {
1052       case T_NIL:
1053       case T_FIXNUM:
1054         rb_bug("rb_gc_mark() called for broken object");
1055         break;
1056
1057       case T_NODE:
1058         switch (nd_type(obj)) {
1059           case NODE_IF:         /* 1,2,3 */
1060           case NODE_FOR:
1061           case NODE_ITER:
1062           case NODE_WHEN:
1063           case NODE_MASGN:
1064           case NODE_RESCUE:
1065           case NODE_RESBODY:
1066           case NODE_CLASS:
1067           case NODE_BLOCK_PASS:
1068             gc_mark(objspace, (VALUE)obj->as.node.u2.node, lev);
1069             /* fall through */
1070           case NODE_BLOCK:      /* 1,3 */
1071           case NODE_OPTBLOCK:
1072           case NODE_ARRAY:
1073           case NODE_DSTR:
1074           case NODE_DXSTR:
1075           case NODE_DREGX:
1076           case NODE_DREGX_ONCE:
1077           case NODE_ENSURE:
1078           case NODE_CALL:
1079           case NODE_DEFS:
1080           case NODE_OP_ASGN1:
1081           case NODE_ARGS:
1082             gc_mark(objspace, (VALUE)obj->as.node.u1.node, lev);
1083             /* fall through */
1084           case NODE_SUPER:      /* 3 */
1085           case NODE_FCALL:
1086           case NODE_DEFN:
1087           case NODE_ARGS_AUX:
1088             ptr = (VALUE)obj->as.node.u3.node;
1089             goto again;
1090
1091           case NODE_METHOD:     /* 1,2 */
1092           case NODE_WHILE:
1093           case NODE_UNTIL:
1094           case NODE_AND:
1095           case NODE_OR:
1096           case NODE_CASE:
1097           case NODE_SCLASS:
1098           case NODE_DOT2:
1099           case NODE_DOT3:
1100           case NODE_FLIP2:
1101           case NODE_FLIP3:
1102           case NODE_MATCH2:
1103           case NODE_MATCH3:
1104           case NODE_OP_ASGN_OR:
1105           case NODE_OP_ASGN_AND:
1106           case NODE_MODULE:
1107           case NODE_ALIAS:
1108           case NODE_VALIAS:
1109           case NODE_ARGSCAT:
1110             gc_mark(objspace, (VALUE)obj->as.node.u1.node, lev);
1111             /* fall through */
1112           case NODE_FBODY:      /* 2 */
1113           case NODE_GASGN:
1114           case NODE_LASGN:
1115           case NODE_DASGN:
1116           case NODE_DASGN_CURR:
1117           case NODE_IASGN:
1118           case NODE_IASGN2:
1119           case NODE_CVASGN:
1120           case NODE_COLON3:
1121           case NODE_OPT_N:
1122           case NODE_EVSTR:
1123           case NODE_UNDEF:
1124           case NODE_POSTEXE:
1125             ptr = (VALUE)obj->as.node.u2.node;
1126             goto again;
1127
1128           case NODE_HASH:       /* 1 */
1129           case NODE_LIT:
1130           case NODE_STR:
1131           case NODE_XSTR:
1132           case NODE_DEFINED:
1133           case NODE_MATCH:
1134           case NODE_RETURN:
1135           case NODE_BREAK:
1136           case NODE_NEXT:
1137           case NODE_YIELD:
1138           case NODE_COLON2:
1139           case NODE_SPLAT:
1140           case NODE_TO_ARY:
1141             ptr = (VALUE)obj->as.node.u1.node;
1142             goto again;
1143
1144           case NODE_SCOPE:      /* 2,3 */
1145           case NODE_CDECL:
1146           case NODE_OPT_ARG:
1147             gc_mark(objspace, (VALUE)obj->as.node.u3.node, lev);
1148             ptr = (VALUE)obj->as.node.u2.node;
1149             goto again;
1150
1151           case NODE_ZARRAY:     /* - */
1152           case NODE_ZSUPER:
1153           case NODE_CFUNC:
1154           case NODE_VCALL:
1155           case NODE_GVAR:
1156           case NODE_LVAR:
1157           case NODE_DVAR:
1158           case NODE_IVAR:
1159           case NODE_CVAR:
1160           case NODE_NTH_REF:
1161           case NODE_BACK_REF:
1162           case NODE_REDO:
1163           case NODE_RETRY:
1164           case NODE_SELF:
1165           case NODE_NIL:
1166           case NODE_TRUE:
1167           case NODE_FALSE:
1168           case NODE_ERRINFO:
1169           case NODE_ATTRSET:
1170           case NODE_BLOCK_ARG:
1171             break;
1172           case NODE_ALLOCA:
1173             mark_locations_array(objspace,
1174                                  (VALUE*)obj->as.node.u1.value,
1175                                  obj->as.node.u3.cnt);
1176             ptr = (VALUE)obj->as.node.u2.node;
1177             goto again;
1178
1179           default:              /* unlisted NODE */
1180             if (is_pointer_to_heap(objspace, obj->as.node.u1.node)) {
1181                 gc_mark(objspace, (VALUE)obj->as.node.u1.node, lev);
1182             }
1183             if (is_pointer_to_heap(objspace, obj->as.node.u2.node)) {
1184                 gc_mark(objspace, (VALUE)obj->as.node.u2.node, lev);
1185             }
1186             if (is_pointer_to_heap(objspace, obj->as.node.u3.node)) {
1187                 gc_mark(objspace, (VALUE)obj->as.node.u3.node, lev);
1188             }
1189         }
1190         return;                 /* no need to mark class. */
1191     }
1192
1193     gc_mark(objspace, obj->as.basic.klass, lev);
1194     switch (obj->as.basic.flags & T_MASK) {
1195       case T_ICLASS:
1196       case T_CLASS:
1197       case T_MODULE:
1198         mark_tbl(objspace, RCLASS_M_TBL(obj), lev);
1199         mark_tbl(objspace, RCLASS_IV_TBL(obj), lev);
1200         ptr = RCLASS_SUPER(obj);
1201         goto again;
1202
1203       case T_ARRAY:
1204         if (FL_TEST(obj, ELTS_SHARED)) {
1205             ptr = obj->as.array.aux.shared;
1206             goto again;
1207         }
1208         else {
1209             long i, len = RARRAY_LEN(obj);
1210             VALUE *ptr = RARRAY_PTR(obj);
1211             for (i=0; i < len; i++) {
1212                 gc_mark(objspace, *ptr++, lev);
1213             }
1214         }
1215         break;
1216
1217       case T_HASH:
1218         mark_hash(objspace, obj->as.hash.ntbl, lev);
1219         ptr = obj->as.hash.ifnone;
1220         goto again;
1221
1222       case T_STRING:
1223 #define STR_ASSOC FL_USER3   /* copied from string.c */
1224         if (FL_TEST(obj, RSTRING_NOEMBED) && FL_ANY(obj, ELTS_SHARED|STR_ASSOC)) {
1225             ptr = obj->as.string.as.heap.aux.shared;
1226             goto again;
1227         }
1228         break;
1229
1230       case T_DATA:
1231         if (obj->as.data.dmark) (*obj->as.data.dmark)(DATA_PTR(obj));
1232         break;
1233
1234       case T_OBJECT:
1235         {
1236             long i, len = ROBJECT_NUMIV(obj);
1237             VALUE *ptr = ROBJECT_IVPTR(obj);
1238             for (i  = 0; i < len; i++) {
1239                 gc_mark(objspace, *ptr++, lev);
1240             }
1241         }
1242         break;
1243
1244       case T_FILE:
1245         if (obj->as.file.fptr)
1246             gc_mark(objspace, obj->as.file.fptr->tied_io_for_writing, lev);
1247         break;
1248
1249       case T_REGEXP:
1250       case T_FLOAT:
1251       case T_BIGNUM:
1252         break;
1253
1254       case T_MATCH:
1255         gc_mark(objspace, obj->as.match.regexp, lev);
1256         if (obj->as.match.str) {
1257             ptr = obj->as.match.str;
1258             goto again;
1259         }
1260         break;
1261
1262       case T_RATIONAL:
1263         gc_mark(objspace, obj->as.rational.num, lev);
1264         gc_mark(objspace, obj->as.rational.den, lev);
1265         break;
1266
1267       case T_COMPLEX:
1268         gc_mark(objspace, obj->as.complex.real, lev);
1269         gc_mark(objspace, obj->as.complex.image, lev);
1270         break;
1271
1272       case T_STRUCT:
1273         {
1274             long len = RSTRUCT_LEN(obj);
1275             VALUE *ptr = RSTRUCT_PTR(obj);
1276
1277             while (len--) {
1278                 gc_mark(objspace, *ptr++, lev);
1279             }
1280         }
1281         break;
1282
1283       case T_VALUES:
1284         {
1285             rb_gc_mark(RVALUES(obj)->v1);
1286             rb_gc_mark(RVALUES(obj)->v2);
1287             ptr = RVALUES(obj)->v3;
1288             goto again;
1289         }
1290         break;
1291
1292       default:
1293         rb_bug("rb_gc_mark(): unknown data type 0x%lx(%p) %s",
1294                obj->as.basic.flags & T_MASK, obj,
1295                is_pointer_to_heap(objspace, obj) ? "corrupted object" : "non object");
1296     }
1297 }
1298
1299 static void obj_free(rb_objspace_t *, VALUE);
1300
1301 static void
1302 finalize_list(rb_objspace_t *objspace, RVALUE *p)
1303 {
1304     while (p) {
1305         RVALUE *tmp = p->as.free.next;
1306         run_final(objspace, (VALUE)p);
1307         if (!FL_TEST(p, FL_SINGLETON)) { /* not freeing page */
1308             VALGRIND_MAKE_MEM_UNDEFINED((void*)p, sizeof(RVALUE));
1309             p->as.free.flags = 0;
1310             p->as.free.next = freelist;
1311             freelist = p;
1312         }
1313         p = tmp;
1314     }
1315 }
1316
1317 static void
1318 free_unused_heaps(rb_objspace_t *objspace)
1319 {
1320     size_t i, j;
1321     RVALUE *last = 0;
1322
1323     for (i = j = 1; j < heaps_used; i++) {
1324         if (heaps[i].limit == 0) {
1325             if (!last) {
1326                 last = heaps[i].membase;
1327             }
1328             else {
1329                 free(heaps[i].membase);
1330             }
1331             heaps_used--;
1332         }
1333         else {
1334             if (i != j) {
1335                 heaps[j] = heaps[i];
1336             }
1337             j++;
1338         }
1339     }
1340     if (last) {
1341         if (last < heaps_freed) {
1342             free(heaps_freed);
1343             heaps_freed = last;
1344         }
1345         else {
1346             free(last);
1347         }
1348     }
1349 }
1350
1351 void rb_gc_abort_threads(void);
1352
1353 static void
1354 gc_sweep(rb_objspace_t *objspace)
1355 {
1356     RVALUE *p, *pend, *final_list;
1357     size_t freed = 0;
1358     size_t i;
1359     size_t live = 0, free_min = 0, do_heap_free = 0;
1360
1361     do_heap_free = (heaps_used * HEAP_OBJ_LIMIT) * 0.65;
1362     free_min = (heaps_used * HEAP_OBJ_LIMIT)  * 0.2;
1363     if (free_min < FREE_MIN) {
1364         do_heap_free = heaps_used * HEAP_OBJ_LIMIT;
1365         free_min = FREE_MIN;
1366     }
1367
1368     freelist = 0;
1369     final_list = deferred_final_list;
1370     deferred_final_list = 0;
1371     for (i = 0; i < heaps_used; i++) {
1372         int n = 0;
1373         RVALUE *free = freelist;
1374         RVALUE *final = final_list;
1375
1376         p = heaps[i].slot; pend = p + heaps[i].limit;
1377         while (p < pend) {
1378             if (!(p->as.basic.flags & FL_MARK)) {
1379                 if (p->as.basic.flags) {
1380                     obj_free(objspace, (VALUE)p);
1381                 }
1382                 if (need_call_final && FL_TEST(p, FL_FINALIZE)) {
1383                     p->as.free.flags = FL_MARK; /* remain marked */
1384                     p->as.free.next = final_list;
1385                     final_list = p;
1386                 }
1387                 else {
1388                     VALGRIND_MAKE_MEM_UNDEFINED((void*)p, sizeof(RVALUE));
1389                     p->as.free.flags = 0;
1390                     p->as.free.next = freelist;
1391                     freelist = p;
1392                 }
1393                 n++;
1394             }
1395             else if (RBASIC(p)->flags == FL_MARK) {
1396                 /* objects to be finalized */
1397                 /* do nothing remain marked */
1398             }
1399             else {
1400                 RBASIC(p)->flags &= ~FL_MARK;
1401                 live++;
1402             }
1403             p++;
1404         }
1405         if (n == heaps[i].limit && freed > do_heap_free) {
1406             RVALUE *pp;
1407
1408             heaps[i].limit = 0;
1409             for (pp = final_list; pp != final; pp = pp->as.free.next) {
1410                 p->as.free.flags |= FL_SINGLETON; /* freeing page mark */
1411             }
1412             freelist = free;    /* cancel this page from freelist */
1413         }
1414         else {
1415             freed += n;
1416         }
1417     }
1418     if (malloc_increase > malloc_limit) {
1419         malloc_limit += (malloc_increase - malloc_limit) * (double)live / (live + freed);
1420         if (malloc_limit < GC_MALLOC_LIMIT) malloc_limit = GC_MALLOC_LIMIT;
1421     }
1422     malloc_increase = 0;
1423     if (freed < free_min) {
1424         set_heaps_increment(objspace);
1425         heaps_increment(objspace);
1426     }
1427     during_gc = 0;
1428
1429     /* clear finalization list */
1430     if (final_list) {
1431         deferred_final_list = final_list;
1432         return;
1433     }
1434     free_unused_heaps(objspace);
1435 }
1436
1437 void
1438 rb_gc_force_recycle(VALUE p)
1439 {
1440     rb_objspace_t *objspace = &rb_objspace;
1441     VALGRIND_MAKE_MEM_UNDEFINED((void*)p, sizeof(RVALUE));
1442     RANY(p)->as.free.flags = 0;
1443     RANY(p)->as.free.next = freelist;
1444     freelist = RANY(p);
1445 }
1446
1447 static void
1448 obj_free(rb_objspace_t *objspace, VALUE obj)
1449 {
1450     switch (RANY(obj)->as.basic.flags & T_MASK) {
1451       case T_NIL:
1452       case T_FIXNUM:
1453       case T_TRUE:
1454       case T_FALSE:
1455         rb_bug("obj_free() called for broken object");
1456         break;
1457     }
1458
1459     if (FL_TEST(obj, FL_EXIVAR)) {
1460         rb_free_generic_ivar((VALUE)obj);
1461     }
1462
1463     switch (RANY(obj)->as.basic.flags & T_MASK) {
1464       case T_OBJECT:
1465         if (!(RANY(obj)->as.basic.flags & ROBJECT_EMBED) &&
1466             RANY(obj)->as.object.as.heap.ivptr) {
1467             RUBY_CRITICAL(free(RANY(obj)->as.object.as.heap.ivptr));
1468         }
1469         break;
1470       case T_MODULE:
1471       case T_CLASS:
1472         rb_clear_cache_by_class((VALUE)obj);
1473         st_free_table(RCLASS_M_TBL(obj));
1474         if (RCLASS_IV_TBL(obj)) {
1475             st_free_table(RCLASS_IV_TBL(obj));
1476         }
1477         if (RCLASS_IV_INDEX_TBL(obj)) {
1478             st_free_table(RCLASS_IV_INDEX_TBL(obj));
1479         }
1480         RUBY_CRITICAL(free(RANY(obj)->as.klass.ptr));
1481         break;
1482       case T_STRING:
1483         rb_str_free(obj);
1484         break;
1485       case T_ARRAY:
1486         rb_ary_free(obj);
1487         break;
1488       case T_HASH:
1489         if (RANY(obj)->as.hash.ntbl) {
1490             st_free_table(RANY(obj)->as.hash.ntbl);
1491         }
1492         break;
1493       case T_REGEXP:
1494         if (RANY(obj)->as.regexp.ptr) {
1495             onig_free(RANY(obj)->as.regexp.ptr);
1496         }
1497         if (RANY(obj)->as.regexp.str) {
1498             RUBY_CRITICAL(free(RANY(obj)->as.regexp.str));
1499         }
1500         break;
1501       case T_DATA:
1502         if (DATA_PTR(obj)) {
1503             if ((long)RANY(obj)->as.data.dfree == -1) {
1504                 RUBY_CRITICAL(free(DATA_PTR(obj)));
1505             }
1506             else if (RANY(obj)->as.data.dfree) {
1507                 (*RANY(obj)->as.data.dfree)(DATA_PTR(obj));
1508             }
1509         }
1510         break;
1511       case T_MATCH:
1512         if (RANY(obj)->as.match.rmatch) {
1513             struct rmatch *rm = RANY(obj)->as.match.rmatch;
1514             onig_region_free(&rm->regs, 0);
1515             if (rm->char_offset)
1516                 RUBY_CRITICAL(free(rm->char_offset));
1517             RUBY_CRITICAL(free(rm));
1518         }
1519         break;
1520       case T_FILE:
1521         if (RANY(obj)->as.file.fptr) {
1522             rb_io_fptr_finalize(RANY(obj)->as.file.fptr);
1523         }
1524         break;
1525       case T_RATIONAL:
1526       case T_COMPLEX:
1527         break;
1528       case T_ICLASS:
1529         /* iClass shares table with the module */
1530         break;
1531
1532       case T_FLOAT:
1533         break;
1534       case T_VALUES:
1535         break;
1536
1537       case T_BIGNUM:
1538         if (!(RBASIC(obj)->flags & RBIGNUM_EMBED_FLAG) && RBIGNUM_DIGITS(obj)) {
1539             RUBY_CRITICAL(free(RBIGNUM_DIGITS(obj)));
1540         }
1541         break;
1542       case T_NODE:
1543         switch (nd_type(obj)) {
1544           case NODE_SCOPE:
1545             if (RANY(obj)->as.node.u1.tbl) {
1546                 RUBY_CRITICAL(free(RANY(obj)->as.node.u1.tbl));
1547             }
1548             break;
1549           case NODE_ALLOCA:
1550             RUBY_CRITICAL(free(RANY(obj)->as.node.u1.node));
1551             break;
1552         }
1553         return;                 /* no need to free iv_tbl */
1554
1555       case T_STRUCT:
1556         if ((RBASIC(obj)->flags & RSTRUCT_EMBED_LEN_MASK) == 0 &&
1557             RANY(obj)->as.rstruct.as.heap.ptr) {
1558             RUBY_CRITICAL(free(RANY(obj)->as.rstruct.as.heap.ptr));
1559         }
1560         break;
1561
1562       default:
1563         rb_bug("gc_sweep(): unknown data type 0x%lx(%p)",
1564                RANY(obj)->as.basic.flags & T_MASK, (void*)obj);
1565     }
1566 }
1567
1568 #ifdef __GNUC__
1569 #if defined(__human68k__) || defined(DJGPP)
1570 #undef rb_setjmp
1571 #undef rb_jmp_buf
1572 #if defined(__human68k__)
1573 typedef unsigned long rb_jmp_buf[8];
1574 __asm__ (".even\n\
1575 _rb_setjmp:\n\
1576         move.l  4(sp),a0\n\
1577         movem.l d3-d7/a3-a5,(a0)\n\
1578         moveq.l #0,d0\n\
1579         rts");
1580 #else
1581 #if defined(DJGPP)
1582 typedef unsigned long rb_jmp_buf[6];
1583 __asm__ (".align 4\n\
1584 _rb_setjmp:\n\
1585         pushl   %ebp\n\
1586         movl    %esp,%ebp\n\
1587         movl    8(%ebp),%ebp\n\
1588         movl    %eax,(%ebp)\n\
1589         movl    %ebx,4(%ebp)\n\
1590         movl    %ecx,8(%ebp)\n\
1591         movl    %edx,12(%ebp)\n\
1592         movl    %esi,16(%ebp)\n\
1593         movl    %edi,20(%ebp)\n\
1594         popl    %ebp\n\
1595         xorl    %eax,%eax\n\
1596         ret");
1597 #endif
1598 #endif
1599 int rb_setjmp (rb_jmp_buf);
1600 #endif /* __human68k__ or DJGPP */
1601 #endif /* __GNUC__ */
1602
1603 #define GC_NOTIFY 0
1604
1605 void rb_vm_mark(void *ptr);
1606
1607 static void
1608 mark_current_machine_context(rb_objspace_t *objspace, rb_thread_t *th)
1609 {
1610     rb_jmp_buf save_regs_gc_mark;
1611     VALUE *stack_start, *stack_end;
1612
1613     SET_STACK_END;
1614 #if STACK_GROW_DIRECTION < 0
1615     stack_start = th->machine_stack_end;
1616     stack_end = th->machine_stack_start;
1617 #elif STACK_GROW_DIRECTION > 0
1618     stack_start = th->machine_stack_start;
1619     stack_end = th->machine_stack_end + 1;
1620 #else
1621     if (th->machine_stack_end < th->machine_stack_start) {
1622         stack_start = th->machine_stack_end;
1623         stack_end = th->machine_stack_start;
1624     }
1625     else {
1626         stack_start = th->machine_stack_start;
1627         stack_end = th->machine_stack_end + 1;
1628     }
1629 #endif
1630
1631     FLUSH_REGISTER_WINDOWS;
1632     /* This assumes that all registers are saved into the jmp_buf (and stack) */
1633     rb_setjmp(save_regs_gc_mark);
1634     mark_locations_array(objspace,
1635                          (VALUE*)save_regs_gc_mark,
1636                          sizeof(save_regs_gc_mark) / sizeof(VALUE));
1637
1638     rb_gc_mark_locations(stack_start, stack_end);
1639 #ifdef __ia64
1640     rb_gc_mark_locations(th->machine_register_stack_start, th->machine_register_stack_end);
1641 #endif
1642 #if defined(__human68k__) || defined(__mc68000__)
1643     mark_locations_array((VALUE*)((char*)STACK_END + 2),
1644                          (STACK_START - STACK_END));
1645 #endif
1646 }
1647
1648 void rb_gc_mark_encodings(void);
1649
1650 static int
1651 garbage_collect(rb_objspace_t *objspace)
1652 {
1653     struct gc_list *list;
1654     rb_thread_t *th = GET_THREAD();
1655
1656     if (GC_NOTIFY) printf("start garbage_collect()\n");
1657
1658     if (!heaps) {
1659         return Qfalse;
1660     }
1661
1662     if (dont_gc || during_gc) {
1663         if (!freelist) {
1664             if (!heaps_increment(objspace)) {
1665                 set_heaps_increment(objspace);
1666                 heaps_increment(objspace);
1667             }
1668         }
1669         return Qtrue;
1670     }
1671     during_gc++;
1672     objspace->count++;
1673
1674     SET_STACK_END;
1675
1676     init_mark_stack(objspace);
1677
1678     th->vm->self ? rb_gc_mark(th->vm->self) : rb_vm_mark(th->vm);
1679
1680     if (finalizer_table) {
1681         mark_tbl(objspace, finalizer_table, 0);
1682     }
1683
1684     mark_current_machine_context(objspace, th);
1685
1686     rb_gc_mark_threads();
1687     rb_gc_mark_symbols();
1688     rb_gc_mark_encodings();
1689
1690     /* mark protected global variables */
1691     for (list = global_List; list; list = list->next) {
1692         rb_gc_mark_maybe(*list->varptr);
1693     }
1694     rb_mark_end_proc();
1695     rb_gc_mark_global_tbl();
1696
1697     mark_tbl(objspace, rb_class_tbl, 0);
1698     rb_gc_mark_trap_list();
1699
1700     /* mark generic instance variables for special constants */
1701     rb_mark_generic_ivar_tbl();
1702
1703     rb_gc_mark_parser();
1704
1705     /* gc_mark objects whose marking are not completed*/
1706     while (!MARK_STACK_EMPTY) {
1707         if (mark_stack_overflow) {
1708             gc_mark_all(objspace);
1709         }
1710         else {
1711             gc_mark_rest(objspace);
1712         }
1713     }
1714
1715     gc_sweep(objspace);
1716
1717     if (GC_NOTIFY) printf("end garbage_collect()\n");
1718     return Qtrue;
1719 }
1720
1721 int
1722 rb_garbage_collect(void)
1723 {
1724     return garbage_collect(&rb_objspace);
1725 }
1726
1727 void
1728 rb_gc_mark_machine_stack(rb_thread_t *th)
1729 {
1730     rb_objspace_t *objspace = &rb_objspace;
1731 #if STACK_GROW_DIRECTION < 0
1732     rb_gc_mark_locations(th->machine_stack_end, th->machine_stack_start);
1733 #elif STACK_GROW_DIRECTION > 0
1734     rb_gc_mark_locations(th->machine_stack_start, th->machine_stack_end);
1735 #else
1736     if (th->machine_stack_start < th->machine_stack_end) {
1737         rb_gc_mark_locations(th->machine_stack_start, th->machine_stack_end);
1738     }
1739     else {
1740         rb_gc_mark_locations(th->machine_stack_end, th->machine_stack_start);
1741     }
1742 #endif
1743 #ifdef __ia64
1744     rb_gc_mark_locations(th->machine_register_stack_start, th->machine_register_stack_end);
1745 #endif
1746 }
1747
1748
1749 /*
1750  *  call-seq:
1751  *     GC.start                     => nil
1752  *     gc.garbage_collect           => nil
1753  *     ObjectSpace.garbage_collect  => nil
1754  *
1755  *  Initiates garbage collection, unless manually disabled.
1756  *
1757  */
1758
1759 VALUE
1760 rb_gc_start(void)
1761 {
1762     rb_gc();
1763     return Qnil;
1764 }
1765
1766 void
1767 ruby_set_stack_size(size_t size)
1768 {
1769     rb_gc_stack_maxsize = size;
1770 }
1771
1772 void
1773 Init_stack(VALUE *addr)
1774 {
1775     ruby_init_stack(addr);
1776 }
1777
1778 #undef ruby_init_stack
1779 void
1780 ruby_init_stack(VALUE *addr
1781 #ifdef __ia64
1782     , void *bsp
1783 #endif
1784     )
1785 {
1786     if (!rb_gc_stack_start ||
1787         STACK_UPPER(&addr,
1788                     rb_gc_stack_start > addr,
1789                     rb_gc_stack_start < addr)) {
1790         rb_gc_stack_start = addr;
1791     }
1792 #ifdef __ia64
1793     if (!rb_gc_register_stack_start ||
1794         (VALUE*)bsp < rb_gc_register_stack_start) {
1795         rb_gc_register_stack_start = (VALUE*)bsp;
1796     }
1797 #endif
1798 #ifdef HAVE_GETRLIMIT
1799     {
1800         struct rlimit rlim;
1801
1802         if (getrlimit(RLIMIT_STACK, &rlim) == 0) {
1803             unsigned int space = rlim.rlim_cur/5;
1804
1805             if (space > 1024*1024) space = 1024*1024;
1806             rb_gc_stack_maxsize = rlim.rlim_cur - space;
1807         }
1808     }
1809 #elif defined _WIN32
1810     {
1811         MEMORY_BASIC_INFORMATION mi;
1812         DWORD size;
1813         DWORD space;
1814
1815         if (VirtualQuery(&mi, &mi, sizeof(mi))) {
1816             size = (char *)mi.BaseAddress - (char *)mi.AllocationBase;
1817             space = size / 5;
1818             if (space > 1024*1024) space = 1024*1024;
1819             rb_gc_stack_maxsize = size - space;
1820         }
1821     }
1822 #endif
1823 }
1824
1825 /*
1826  * Document-class: ObjectSpace
1827  *
1828  *  The <code>ObjectSpace</code> module contains a number of routines
1829  *  that interact with the garbage collection facility and allow you to
1830  *  traverse all living objects with an iterator.
1831  *
1832  *  <code>ObjectSpace</code> also provides support for object
1833  *  finalizers, procs that will be called when a specific object is
1834  *  about to be destroyed by garbage collection.
1835  *
1836  *     include ObjectSpace
1837  *
1838  *
1839  *     a = "A"
1840  *     b = "B"
1841  *     c = "C"
1842  *
1843  *
1844  *     define_finalizer(a, proc {|id| puts "Finalizer one on #{id}" })
1845  *     define_finalizer(a, proc {|id| puts "Finalizer two on #{id}" })
1846  *     define_finalizer(b, proc {|id| puts "Finalizer three on #{id}" })
1847  *
1848  *  <em>produces:</em>
1849  *
1850  *     Finalizer three on 537763470
1851  *     Finalizer one on 537763480
1852  *     Finalizer two on 537763480
1853  *
1854  */
1855
1856 void
1857 Init_heap(void)
1858 {
1859     if (!rb_gc_stack_start) {
1860         Init_stack(0);
1861     }
1862     init_heap(&rb_objspace);
1863 }
1864
1865 static VALUE
1866 os_obj_of(rb_objspace_t *objspace, VALUE of)
1867 {
1868     size_t i;
1869     size_t n = 0;
1870
1871     for (i = 0; i < heaps_used; i++) {
1872         RVALUE *p, *pend;
1873
1874         p = heaps[i].slot; pend = p + heaps[i].limit;
1875         for (;p < pend; p++) {
1876             if (p->as.basic.flags) {
1877                 switch (BUILTIN_TYPE(p)) {
1878                   case T_NONE:
1879                   case T_ICLASS:
1880                   case T_NODE:
1881                   case T_VALUES:
1882                     continue;
1883                   case T_CLASS:
1884                     if (FL_TEST(p, FL_SINGLETON)) continue;
1885                   default:
1886                     if (!p->as.basic.klass) continue;
1887                     if (!of || rb_obj_is_kind_of((VALUE)p, of)) {
1888                         rb_yield((VALUE)p);
1889                         n++;
1890                     }
1891                 }
1892             }
1893         }
1894     }
1895
1896     return SIZET2NUM(n);
1897 }
1898
1899 /*
1900  *  call-seq:
1901  *     ObjectSpace.each_object([module]) {|obj| ... } => fixnum
1902  *
1903  *  Calls the block once for each living, nonimmediate object in this
1904  *  Ruby process. If <i>module</i> is specified, calls the block
1905  *  for only those classes or modules that match (or are a subclass of)
1906  *  <i>module</i>. Returns the number of objects found. Immediate
1907  *  objects (<code>Fixnum</code>s, <code>Symbol</code>s
1908  *  <code>true</code>, <code>false</code>, and <code>nil</code>) are
1909  *  never returned. In the example below, <code>each_object</code>
1910  *  returns both the numbers we defined and several constants defined in
1911  *  the <code>Math</code> module.
1912  *
1913  *     a = 102.7
1914  *     b = 95       # Won't be returned
1915  *     c = 12345678987654321
1916  *     count = ObjectSpace.each_object(Numeric) {|x| p x }
1917  *     puts "Total count: #{count}"
1918  *
1919  *  <em>produces:</em>
1920  *
1921  *     12345678987654321
1922  *     102.7
1923  *     2.71828182845905
1924  *     3.14159265358979
1925  *     2.22044604925031e-16
1926  *     1.7976931348623157e+308
1927  *     2.2250738585072e-308
1928  *     Total count: 7
1929  *
1930  */
1931
1932 static VALUE
1933 os_each_obj(int argc, VALUE *argv, VALUE os)
1934 {
1935     VALUE of;
1936
1937     rb_secure(4);
1938     if (argc == 0) {
1939         of = 0;
1940     }
1941     else {
1942         rb_scan_args(argc, argv, "01", &of);
1943     }
1944     RETURN_ENUMERATOR(os, 1, &of);
1945     return os_obj_of(&rb_objspace, of);
1946 }
1947
1948 /*
1949  *  call-seq:
1950  *     ObjectSpace.undefine_finalizer(obj)
1951  *
1952  *  Removes all finalizers for <i>obj</i>.
1953  *
1954  */
1955
1956 static VALUE
1957 undefine_final(VALUE os, VALUE obj)
1958 {
1959     rb_objspace_t *objspace = &rb_objspace;
1960     if (finalizer_table) {
1961         st_delete(finalizer_table, (st_data_t*)&obj, 0);
1962     }
1963     return obj;
1964 }
1965
1966 /*
1967  *  call-seq:
1968  *     ObjectSpace.define_finalizer(obj, aProc=proc())
1969  *
1970  *  Adds <i>aProc</i> as a finalizer, to be called after <i>obj</i>
1971  *  was destroyed.
1972  *
1973  */
1974
1975 static VALUE
1976 define_final(int argc, VALUE *argv, VALUE os)
1977 {
1978     rb_objspace_t *objspace = &rb_objspace;
1979     VALUE obj, block, table;
1980
1981     rb_scan_args(argc, argv, "11", &obj, &block);
1982     if (argc == 1) {
1983         block = rb_block_proc();
1984     }
1985     else if (!rb_respond_to(block, rb_intern("call"))) {
1986         rb_raise(rb_eArgError, "wrong type argument %s (should be callable)",
1987                  rb_obj_classname(block));
1988     }
1989     need_call_final = 1;
1990     FL_SET(obj, FL_FINALIZE);
1991
1992     block = rb_ary_new3(2, INT2FIX(rb_safe_level()), block);
1993
1994     if (!finalizer_table) {
1995         finalizer_table = st_init_numtable();
1996     }
1997     if (st_lookup(finalizer_table, obj, &table)) {
1998         rb_ary_push(table, block);
1999     }
2000     else {
2001         st_add_direct(finalizer_table, obj, rb_ary_new3(1, block));
2002     }
2003     return block;
2004 }
2005
2006 void
2007 rb_gc_copy_finalizer(VALUE dest, VALUE obj)
2008 {
2009     rb_objspace_t *objspace = &rb_objspace;
2010     VALUE table;
2011
2012     if (!finalizer_table) return;
2013     if (!FL_TEST(obj, FL_FINALIZE)) return;
2014     if (st_lookup(finalizer_table, obj, &table)) {
2015         st_insert(finalizer_table, dest, table);
2016     }
2017     FL_SET(dest, FL_FINALIZE);
2018 }
2019
2020 static VALUE
2021 run_single_final(VALUE arg)
2022 {
2023     VALUE *args = (VALUE *)arg;
2024     rb_eval_cmd(args[0], args[1], (int)args[2]);
2025     return Qnil;
2026 }
2027
2028 static void
2029 run_final(rb_objspace_t *objspace, VALUE obj)
2030 {
2031     long i;
2032     int status, critical_save = rb_thread_critical;
2033     VALUE args[3], table, objid;
2034
2035     objid = rb_obj_id(obj);     /* make obj into id */
2036     rb_thread_critical = Qtrue;
2037     args[1] = 0;
2038     args[2] = (VALUE)rb_safe_level();
2039     if (finalizer_table && st_delete(finalizer_table, (st_data_t*)&obj, &table)) {
2040         if (!args[1] && RARRAY_LEN(table) > 0) {
2041             args[1] = rb_obj_freeze(rb_ary_new3(1, objid));
2042         }
2043         for (i=0; i<RARRAY_LEN(table); i++) {
2044             VALUE final = RARRAY_PTR(table)[i];
2045             args[0] = RARRAY_PTR(final)[1];
2046             args[2] = FIX2INT(RARRAY_PTR(final)[0]);
2047             rb_protect(run_single_final, (VALUE)args, &status);
2048         }
2049     }
2050     rb_thread_critical = critical_save;
2051 }
2052
2053 static void
2054 gc_finalize_deferred(rb_objspace_t *objspace)
2055 {
2056     RVALUE *p = deferred_final_list;
2057
2058     during_gc++;
2059     deferred_final_list = 0;
2060     if (p) {
2061         finalize_list(objspace, p);
2062     }
2063     free_unused_heaps(objspace);
2064     during_gc = 0;
2065 }
2066
2067 void
2068 rb_gc_finalize_deferred(void)
2069 {
2070     gc_finalize_deferred(&rb_objspace);
2071 }
2072
2073 void
2074 rb_gc_call_finalizer_at_exit(void)
2075 {
2076     rb_objspace_t *objspace = &rb_objspace;
2077     RVALUE *p, *pend;
2078     size_t i;
2079
2080     /* finalizers are part of garbage collection */
2081     during_gc++;
2082     /* run finalizers */
2083     if (need_call_final) {
2084         p = deferred_final_list;
2085         deferred_final_list = 0;
2086         finalize_list(objspace, p);
2087         for (i = 0; i < heaps_used; i++) {
2088             p = heaps[i].slot; pend = p + heaps[i].limit;
2089             while (p < pend) {
2090                 if (FL_TEST(p, FL_FINALIZE)) {
2091                     FL_UNSET(p, FL_FINALIZE);
2092                     p->as.basic.klass = 0;
2093                     run_final(objspace, (VALUE)p);
2094                 }
2095                 p++;
2096             }
2097         }
2098     }
2099     /* run data object's finalizers */
2100     for (i = 0; i < heaps_used; i++) {
2101         p = heaps[i].slot; pend = p + heaps[i].limit;
2102         while (p < pend) {
2103             if (BUILTIN_TYPE(p) == T_DATA &&
2104                 DATA_PTR(p) && RANY(p)->as.data.dfree &&
2105                 RANY(p)->as.basic.klass != rb_cThread) {
2106                 p->as.free.flags = 0;
2107                 if ((long)RANY(p)->as.data.dfree == -1) {
2108                     RUBY_CRITICAL(free(DATA_PTR(p)));
2109                 }
2110                 else if (RANY(p)->as.data.dfree) {
2111                     (*RANY(p)->as.data.dfree)(DATA_PTR(p));
2112                 }
2113                 VALGRIND_MAKE_MEM_UNDEFINED((void*)p, sizeof(RVALUE));
2114             }
2115             else if (BUILTIN_TYPE(p) == T_FILE) {
2116                 if (rb_io_fptr_finalize(RANY(p)->as.file.fptr)) {
2117                     p->as.free.flags = 0;
2118                     VALGRIND_MAKE_MEM_UNDEFINED((void*)p, sizeof(RVALUE));
2119                 }
2120             }
2121             p++;
2122         }
2123     }
2124     during_gc = 0;
2125 }
2126
2127 void
2128 rb_gc(void)
2129 {
2130     rb_objspace_t *objspace = &rb_objspace;
2131     garbage_collect(objspace);
2132     gc_finalize_deferred(objspace);
2133 }
2134
2135 /*
2136  *  call-seq:
2137  *     ObjectSpace._id2ref(object_id) -> an_object
2138  *
2139  *  Converts an object id to a reference to the object. May not be
2140  *  called on an object id passed as a parameter to a finalizer.
2141  *
2142  *     s = "I am a string"                    #=> "I am a string"
2143  *     r = ObjectSpace._id2ref(s.object_id)   #=> "I am a string"
2144  *     r == s                                 #=> true
2145  *
2146  */
2147
2148 static VALUE
2149 id2ref(VALUE obj, VALUE objid)
2150 {
2151 #if SIZEOF_LONG == SIZEOF_VOIDP
2152 #define NUM2PTR(x) NUM2ULONG(x)
2153 #elif SIZEOF_LONG_LONG == SIZEOF_VOIDP
2154 #define NUM2PTR(x) NUM2ULL(x)
2155 #endif
2156     rb_objspace_t *objspace = &rb_objspace;
2157     VALUE ptr;
2158     void *p0;
2159
2160     rb_secure(4);
2161     ptr = NUM2PTR(objid);
2162     p0 = (void *)ptr;
2163
2164     if (ptr == Qtrue) return Qtrue;
2165     if (ptr == Qfalse) return Qfalse;
2166     if (ptr == Qnil) return Qnil;
2167     if (FIXNUM_P(ptr)) return (VALUE)ptr;
2168     ptr = objid ^ FIXNUM_FLAG;  /* unset FIXNUM_FLAG */
2169
2170     if ((ptr % sizeof(RVALUE)) == (4 << 2)) {
2171         ID symid = ptr / sizeof(RVALUE);
2172         if (rb_id2name(symid) == 0)
2173             rb_raise(rb_eRangeError, "%p is not symbol id value", p0);
2174         return ID2SYM(symid);
2175     }
2176
2177     if (!is_pointer_to_heap(objspace, (void *)ptr) ||
2178         BUILTIN_TYPE(ptr) >= T_VALUES || BUILTIN_TYPE(ptr) == T_ICLASS) {
2179         rb_raise(rb_eRangeError, "%p is not id value", p0);
2180     }
2181     if (BUILTIN_TYPE(ptr) == 0 || RBASIC(ptr)->klass == 0) {
2182         rb_raise(rb_eRangeError, "%p is recycled object", p0);
2183     }
2184     return (VALUE)ptr;
2185 }
2186
2187 /*
2188  *  Document-method: __id__
2189  *  Document-method: object_id
2190  *
2191  *  call-seq:
2192  *     obj.__id__       => fixnum
2193  *     obj.object_id    => fixnum
2194  *
2195  *  Returns an integer identifier for <i>obj</i>. The same number will
2196  *  be returned on all calls to <code>id</code> for a given object, and
2197  *  no two active objects will share an id.
2198  *  <code>Object#object_id</code> is a different concept from the
2199  *  <code>:name</code> notation, which returns the symbol id of
2200  *  <code>name</code>. Replaces the deprecated <code>Object#id</code>.
2201  */
2202
2203 /*
2204  *  call-seq:
2205  *     obj.hash    => fixnum
2206  *
2207  *  Generates a <code>Fixnum</code> hash value for this object. This
2208  *  function must have the property that <code>a.eql?(b)</code> implies
2209  *  <code>a.hash == b.hash</code>. The hash value is used by class
2210  *  <code>Hash</code>. Any hash value that exceeds the capacity of a
2211  *  <code>Fixnum</code> will be truncated before being used.
2212  */
2213
2214 VALUE
2215 rb_obj_id(VALUE obj)
2216 {
2217     /*
2218      *                32-bit VALUE space
2219      *          MSB ------------------------ LSB
2220      *  false   00000000000000000000000000000000
2221      *  true    00000000000000000000000000000010
2222      *  nil     00000000000000000000000000000100
2223      *  undef   00000000000000000000000000000110
2224      *  symbol  ssssssssssssssssssssssss00001110
2225      *  object  oooooooooooooooooooooooooooooo00        = 0 (mod sizeof(RVALUE))
2226      *  fixnum  fffffffffffffffffffffffffffffff1
2227      *
2228      *                    object_id space
2229      *                                       LSB
2230      *  false   00000000000000000000000000000000
2231      *  true    00000000000000000000000000000010
2232      *  nil     00000000000000000000000000000100
2233      *  undef   00000000000000000000000000000110
2234      *  symbol   000SSSSSSSSSSSSSSSSSSSSSSSSSSS0        S...S % A = 4 (S...S = s...s * A + 4)
2235      *  object   oooooooooooooooooooooooooooooo0        o...o % A = 0
2236      *  fixnum  fffffffffffffffffffffffffffffff1        bignum if required
2237      *
2238      *  where A = sizeof(RVALUE)/4
2239      *
2240      *  sizeof(RVALUE) is
2241      *  20 if 32-bit, double is 4-byte aligned
2242      *  24 if 32-bit, double is 8-byte aligned
2243      *  40 if 64-bit
2244      */
2245     if (TYPE(obj) == T_SYMBOL) {
2246         return (SYM2ID(obj) * sizeof(RVALUE) + (4 << 2)) | FIXNUM_FLAG;
2247     }
2248     if (SPECIAL_CONST_P(obj)) {
2249         return LONG2NUM((SIGNED_VALUE)obj);
2250     }
2251     return (VALUE)((SIGNED_VALUE)obj|FIXNUM_FLAG);
2252 }
2253
2254 /*
2255  *  call-seq:
2256  *     ObjectSpace.count_objects([result_hash]) -> hash
2257  *
2258  *  Counts objects for each type.
2259  *
2260  *  It returns a hash as:
2261  *  {:TOTAL=>10000, :FREE=>3011, :T_OBJECT=>6, :T_CLASS=>404, ...}
2262  *
2263  *  If the optional argument, result_hash, is given,
2264  *  it is overwritten and returned.
2265  *  This is intended to avoid probe effect.
2266  *
2267  *  The contents of the returned hash is implementation defined.
2268  *  It may be changed in future.
2269  *
2270  *  This method is not expected to work except C Ruby.
2271  *
2272  */
2273
2274 static VALUE
2275 count_objects(int argc, VALUE *argv, VALUE os)
2276 {
2277     rb_objspace_t *objspace = &rb_objspace;
2278     size_t counts[T_MASK+1];
2279     size_t freed = 0;
2280     size_t total = 0;
2281     size_t i;
2282     VALUE hash;
2283
2284     if (rb_scan_args(argc, argv, "01", &hash) == 1) {
2285         if (TYPE(hash) != T_HASH)
2286             rb_raise(rb_eTypeError, "non-hash given");
2287     }
2288
2289     for (i = 0; i <= T_MASK; i++) {
2290         counts[i] = 0;
2291     }
2292
2293     for (i = 0; i < heaps_used; i++) {
2294         RVALUE *p, *pend;
2295
2296         p = heaps[i].slot; pend = p + heaps[i].limit;
2297         for (;p < pend; p++) {
2298             if (p->as.basic.flags) {
2299                 counts[BUILTIN_TYPE(p)]++;
2300             }
2301             else {
2302                 freed++;
2303             }
2304         }
2305         total += heaps[i].limit;
2306     }
2307
2308     if (hash == Qnil)
2309         hash = rb_hash_new();
2310     rb_hash_aset(hash, ID2SYM(rb_intern("TOTAL")), SIZET2NUM(total));
2311     rb_hash_aset(hash, ID2SYM(rb_intern("FREE")), SIZET2NUM(freed));
2312     for (i = 0; i <= T_MASK; i++) {
2313         VALUE type;
2314         switch (i) {
2315 #define COUNT_TYPE(t) case t: type = ID2SYM(rb_intern(#t)); break;
2316             COUNT_TYPE(T_NONE);
2317             COUNT_TYPE(T_OBJECT);
2318             COUNT_TYPE(T_CLASS);
2319             COUNT_TYPE(T_MODULE);
2320             COUNT_TYPE(T_FLOAT);
2321             COUNT_TYPE(T_STRING);
2322             COUNT_TYPE(T_REGEXP);
2323             COUNT_TYPE(T_ARRAY);
2324             COUNT_TYPE(T_HASH);
2325             COUNT_TYPE(T_STRUCT);
2326             COUNT_TYPE(T_BIGNUM);
2327             COUNT_TYPE(T_FILE);
2328             COUNT_TYPE(T_DATA);
2329             COUNT_TYPE(T_MATCH);
2330             COUNT_TYPE(T_COMPLEX);
2331             COUNT_TYPE(T_RATIONAL);
2332             COUNT_TYPE(T_NIL);
2333             COUNT_TYPE(T_TRUE);
2334             COUNT_TYPE(T_FALSE);
2335             COUNT_TYPE(T_SYMBOL);
2336             COUNT_TYPE(T_FIXNUM);
2337             COUNT_TYPE(T_VALUES);
2338             COUNT_TYPE(T_UNDEF);
2339             COUNT_TYPE(T_NODE);
2340             COUNT_TYPE(T_ICLASS);
2341 #undef COUNT_TYPE
2342           default:              type = INT2NUM(i); break;
2343         }
2344         if (counts[i])
2345             rb_hash_aset(hash, type, SIZET2NUM(counts[i]));
2346     }
2347
2348     return hash;
2349 }
2350
2351 /*
2352  *  call-seq:
2353  *     GC.count -> Integer
2354  *
2355  *  The number of times GC occured.
2356  *
2357  *  It returns the number of times GC occured since the process started.
2358  *
2359  */
2360
2361 static VALUE
2362 gc_count(VALUE self)
2363 {
2364     return UINT2NUM((&rb_objspace)->count);
2365 }
2366
2367 /*
2368  *  The <code>GC</code> module provides an interface to Ruby's mark and
2369  *  sweep garbage collection mechanism. Some of the underlying methods
2370  *  are also available via the <code>ObjectSpace</code> module.
2371  */
2372
2373 void
2374 Init_GC(void)
2375 {
2376     VALUE rb_mObSpace;
2377
2378     rb_mGC = rb_define_module("GC");
2379     rb_define_singleton_method(rb_mGC, "start", rb_gc_start, 0);
2380     rb_define_singleton_method(rb_mGC, "enable", rb_gc_enable, 0);
2381     rb_define_singleton_method(rb_mGC, "disable", rb_gc_disable, 0);
2382     rb_define_singleton_method(rb_mGC, "stress", gc_stress_get, 0);
2383     rb_define_singleton_method(rb_mGC, "stress=", gc_stress_set, 1);
2384     rb_define_singleton_method(rb_mGC, "count", gc_count, 0);
2385     rb_define_method(rb_mGC, "garbage_collect", rb_gc_start, 0);
2386
2387     rb_mObSpace = rb_define_module("ObjectSpace");
2388     rb_define_module_function(rb_mObSpace, "each_object", os_each_obj, -1);
2389     rb_define_module_function(rb_mObSpace, "garbage_collect", rb_gc_start, 0);
2390
2391     rb_define_module_function(rb_mObSpace, "define_finalizer", define_final, -1);
2392     rb_define_module_function(rb_mObSpace, "undefine_finalizer", undefine_final, 1);
2393
2394     rb_define_module_function(rb_mObSpace, "_id2ref", id2ref, 1);
2395
2396     rb_global_variable(&nomem_error);
2397     nomem_error = rb_exc_new2(rb_eNoMemError, "failed to allocate memory");
2398
2399     rb_define_method(rb_mKernel, "hash", rb_obj_id, 0);
2400     rb_define_method(rb_mKernel, "__id__", rb_obj_id, 0);
2401     rb_define_method(rb_mKernel, "object_id", rb_obj_id, 0);
2402
2403     rb_define_module_function(rb_mObSpace, "count_objects", count_objects, -1);
2404 }