src/runtime/purify.c

   1 /*
   2  * C-level stuff to implement Lisp-level PURIFY
   3  */
   4
   5 /*
   6  * This software is part of the SBCL system. See the README file for
   7  * more information.
   8  *
   9  * This software is derived from the CMU CL system, which was
  10  * written at Carnegie Mellon University and released into the
  11  * public domain. The software is in the public domain and is
  12  * provided with absolutely no warranty. See the COPYING and CREDITS
  13  * files for more information.
  14  */
  15
  16 #include <stdio.h>
  17 #include <sys/types.h>
  18 #include <stdlib.h>
  19
  20 #include "runtime.h"
  21 #include "os.h"
  22 #include "sbcl.h"
  23 #include "globals.h"
  24 #include "validate.h"
  25 #include "interrupt.h"
  26 #include "purify.h"
  27 #include "interr.h"
  28 #ifdef GENCGC
  29 #include "gencgc.h"
  30 #endif
  31
  32 #define PRINTNOISE
  33
  34 #if defined(ibmrt) || defined(__i386__)
  35 /* again, what's so special about the x86 that this is differently
  36  * visible there than on other platforms? -dan 20010125
  37  */
  38 static lispobj *dynamic_space_free_pointer;
  39 #endif
  40
  41 #define gc_abort() \
  42   lose("GC invariant lost, file \"%s\", line %d", __FILE__, __LINE__)
  43
  44 #if 1
  45 #define gc_assert(ex) do { \
  46         if (!(ex)) gc_abort(); \
  47 } while (0)
  48 #else
  49 #define gc_assert(ex)
  50 #endif
  51
  52 \f
  53 /* These hold the original end of the read_only and static spaces so
  54  * we can tell what are forwarding pointers. */
  55
  56 static lispobj *read_only_end, *static_end;
  57
  58 static lispobj *read_only_free, *static_free;
  59
  60 static lispobj *pscav(lispobj *addr, int nwords, boolean constant);
  61
  62 #define LATERBLOCKSIZE 1020
  63 #define LATERMAXCOUNT 10
  64
  65 static struct
  66 later {
  67     struct later *next;
  68     union {
  69         lispobj *ptr;
  70         int count;
  71     } u[LATERBLOCKSIZE];
  72 } *later_blocks = NULL;
  73 static int later_count = 0;
  74
  75 #define CEILING(x,y) (((x) + ((y) - 1)) & (~((y) - 1)))
  76 #define NWORDS(x,y) (CEILING((x),(y)) / (y))
  77
  78 #ifdef sparc
  79 #define RAW_ADDR_OFFSET 0
  80 #else
  81 #define RAW_ADDR_OFFSET (6*sizeof(lispobj) - type_FunctionPointer)
  82 #endif
  83 \f
  84 static boolean
  85 forwarding_pointer_p(lispobj obj)
  86 {
  87     lispobj *ptr;
  88
  89     ptr = (lispobj *)obj;
  90
  91     return ((static_end <= ptr && ptr <= static_free) ||
  92             (read_only_end <= ptr && ptr <= read_only_free));
  93 }
  94
  95 static boolean
  96 dynamic_pointer_p(lispobj ptr)
  97 {
  98 #ifndef __i386__
  99     /* KLUDGE: This has an implicit dependence on the ordering of
 100      * address spaces, and is therefore basically wrong. I'd fix it,
 101      * but I don't have a non-386 port to test it on. Porters are
 102      * encouraged to fix it. -- WHN 2000-10-17 */
 103     return (ptr >= (lispobj)DYNAMIC_SPACE_START);
 104 #else
 105     /* Be more conservative, and remember, this is a maybe. */
 106     return (ptr >= (lispobj)DYNAMIC_SPACE_START
 107             &&
 108             ptr < (lispobj)dynamic_space_free_pointer);
 109 #endif
 110 }
 111
 112 \f
 113 #ifdef __i386__
 114
 115 #ifdef WANT_CGC
 116 /* original x86/CGC stack scavenging code by Paul Werkowski */
 117
 118 static int
 119 maybe_can_move_p(lispobj thing)
 120 {
 121     lispobj *thingp,header;
 122     if (dynamic_pointer_p(thing)) { /* in dynamic space */
 123         thingp = (lispobj*)PTR(thing);
 124         header = *thingp;
 125         if (Pointerp(header) && forwarding_pointer_p(header)) {
 126             return -1;          /* must change it */
 127         } else if (LowtagOf(thing) == type_ListPointer) {
 128             return type_ListPointer;    /* can we check this somehow */
 129         } else if (thing & 3) { /* not fixnum */
 130             int kind = TypeOf(header);
 131             /* printf(" %x %x",header,kind); */
 132             switch (kind) {             /* something with a header */
 133             case type_Bignum:
 134             case type_SingleFloat:
 135             case type_DoubleFloat:
 136 #ifdef type_LongFloat
 137             case type_LongFloat:
 138 #endif
 139             case type_Sap:
 140             case type_SimpleVector:
 141             case type_SimpleString:
 142             case type_SimpleBitVector:
 143             case type_SimpleArrayUnsignedByte2:
 144             case type_SimpleArrayUnsignedByte4:
 145             case type_SimpleArrayUnsignedByte8:
 146             case type_SimpleArrayUnsignedByte16:
 147             case type_SimpleArrayUnsignedByte32:
 148 #ifdef type_SimpleArraySignedByte8
 149             case type_SimpleArraySignedByte8:
 150 #endif
 151 #ifdef type_SimpleArraySignedByte16
 152             case type_SimpleArraySignedByte16:
 153 #endif
 154 #ifdef type_SimpleArraySignedByte30
 155             case type_SimpleArraySignedByte30:
 156 #endif
 157 #ifdef type_SimpleArraySignedByte32
 158             case type_SimpleArraySignedByte32:
 159 #endif
 160             case type_SimpleArraySingleFloat:
 161             case type_SimpleArrayDoubleFloat:
 162 #ifdef type_SimpleArrayLongFloat
 163             case type_SimpleArrayLongFloat:
 164 #endif
 165 #ifdef type_SimpleArrayComplexSingleFloat
 166             case type_SimpleArrayComplexSingleFloat:
 167 #endif
 168 #ifdef type_SimpleArrayComplexDoubleFloat
 169             case type_SimpleArrayComplexDoubleFloat:
 170 #endif
 171 #ifdef type_SimpleArrayComplexLongFloat
 172             case type_SimpleArrayComplexLongFloat:
 173 #endif
 174             case type_CodeHeader:
 175             case type_FunctionHeader:
 176             case type_ClosureFunctionHeader:
 177             case type_ReturnPcHeader:
 178             case type_ClosureHeader:
 179             case type_FuncallableInstanceHeader:
 180             case type_InstanceHeader:
 181             case type_ValueCellHeader:
 182             case type_ByteCodeFunction:
 183             case type_ByteCodeClosure:
 184             case type_WeakPointer:
 185             case type_Fdefn:
 186                 return kind;
 187                 break;
 188             default:
 189                 return 0;
 190             }
 191         }
 192     }
 193     return 0;
 194 }
 195
 196 static int pverbose=0;
 197 #define PVERBOSE pverbose
 198 static void
 199 carefully_pscav_stack(lispobj*lowaddr, lispobj*base)
 200 {
 201     lispobj *sp = lowaddr;
 202     while (sp < base) {
 203         int k;
 204         lispobj thing = *sp;
 205         if ((unsigned)thing & 0x3) {    /* may be pointer */
 206             /* need to check for valid float/double? */
 207             k = maybe_can_move_p(thing);
 208             if(PVERBOSE)printf("%8x %8x %d\n",sp, thing, k);
 209             if(k)
 210                 pscav(sp, 1, 0);
 211         }
 212         sp++;
 213     }
 214 }
 215 #endif
 216
 217 #ifdef GENCGC
 218 /*
 219  * enhanced x86/GENCGC stack scavenging by Douglas Crosher
 220  *
 221  * Scavenging the stack on the i386 is problematic due to conservative
 222  * roots and raw return addresses. Here it is handled in two passes:
 223  * the first pass runs before any objects are moved and tries to
 224  * identify valid pointers and return address on the stack, the second
 225  * pass scavenges these.
 226  */
 227
 228 static unsigned pointer_filter_verbose = 0;
 229
 230 static int
 231 valid_dynamic_space_pointer(lispobj *pointer, lispobj *start_addr)
 232 {
 233     /* If it's not a return address then it needs to be a valid Lisp
 234      * pointer. */
 235     if (!Pointerp((lispobj)pointer))
 236         return 0;
 237
 238     /* Check that the object pointed to is consistent with the pointer
 239      * low tag. */
 240     switch (LowtagOf((lispobj)pointer)) {
 241     case type_FunctionPointer:
 242         /* Start_addr should be the enclosing code object, or a closure
 243          * header. */
 244         switch (TypeOf(*start_addr)) {
 245         case type_CodeHeader:
 246             /* This case is probably caught above. */
 247             break;
 248         case type_ClosureHeader:
 249         case type_FuncallableInstanceHeader:
 250         case type_ByteCodeFunction:
 251         case type_ByteCodeClosure:
 252             if ((int)pointer != ((int)start_addr+type_FunctionPointer)) {
 253                 if (pointer_filter_verbose) {
 254                     fprintf(stderr,"*Wf2: %x %x %x\n", (unsigned int) pointer,
 255                             (unsigned int) start_addr, *start_addr);
 256                 }
 257                 return 0;
 258             }
 259             break;
 260         default:
 261             if (pointer_filter_verbose) {
 262                 fprintf(stderr,"*Wf3: %x %x %x\n", (unsigned int) pointer,
 263                         (unsigned int) start_addr, *start_addr);
 264             }
 265             return 0;
 266         }
 267         break;
 268     case type_ListPointer:
 269         if ((int)pointer != ((int)start_addr+type_ListPointer)) {
 270             if (pointer_filter_verbose)
 271                 fprintf(stderr,"*Wl1: %x %x %x\n", (unsigned int) pointer,
 272                         (unsigned int) start_addr, *start_addr);
 273             return 0;
 274         }
 275         /* Is it plausible cons? */
 276         if((Pointerp(start_addr[0])
 277             || ((start_addr[0] & 3) == 0) /* fixnum */
 278             || (TypeOf(start_addr[0]) == type_BaseChar)
 279             || (TypeOf(start_addr[0]) == type_UnboundMarker))
 280            && (Pointerp(start_addr[1])
 281                || ((start_addr[1] & 3) == 0) /* fixnum */
 282                || (TypeOf(start_addr[1]) == type_BaseChar)
 283                || (TypeOf(start_addr[1]) == type_UnboundMarker))) {
 284             break;
 285         } else {
 286             if (pointer_filter_verbose) {
 287                 fprintf(stderr,"*Wl2: %x %x %x\n", (unsigned int) pointer,
 288                         (unsigned int) start_addr, *start_addr);
 289             }
 290             return 0;
 291         }
 292     case type_InstancePointer:
 293         if ((int)pointer != ((int)start_addr+type_InstancePointer)) {
 294             if (pointer_filter_verbose) {
 295                 fprintf(stderr,"*Wi1: %x %x %x\n", (unsigned int) pointer,
 296                         (unsigned int) start_addr, *start_addr);
 297             }
 298             return 0;
 299         }
 300         if (TypeOf(start_addr[0]) != type_InstanceHeader) {
 301             if (pointer_filter_verbose) {
 302                 fprintf(stderr,"*Wi2: %x %x %x\n", (unsigned int) pointer,
 303                         (unsigned int) start_addr, *start_addr);
 304             }
 305             return 0;
 306         }
 307         break;
 308     case type_OtherPointer:
 309         if ((int)pointer != ((int)start_addr+type_OtherPointer)) {
 310             if (pointer_filter_verbose) {
 311                 fprintf(stderr,"*Wo1: %x %x %x\n", (unsigned int) pointer,
 312                         (unsigned int) start_addr, *start_addr);
 313             }
 314             return 0;
 315         }
 316         /* Is it plausible?  Not a cons. X should check the headers. */
 317         if(Pointerp(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
 318             if (pointer_filter_verbose) {
 319                 fprintf(stderr,"*Wo2: %x %x %x\n", (unsigned int) pointer,
 320                         (unsigned int) start_addr, *start_addr);
 321             }
 322             return 0;
 323         }
 324         switch (TypeOf(start_addr[0])) {
 325         case type_UnboundMarker:
 326         case type_BaseChar:
 327             if (pointer_filter_verbose) {
 328                 fprintf(stderr,"*Wo3: %x %x %x\n", (unsigned int) pointer,
 329                         (unsigned int) start_addr, *start_addr);
 330             }
 331             return 0;
 332
 333             /* only pointed to by function pointers? */
 334         case type_ClosureHeader:
 335         case type_FuncallableInstanceHeader:
 336         case type_ByteCodeFunction:
 337         case type_ByteCodeClosure:
 338             if (pointer_filter_verbose) {
 339                 fprintf(stderr,"*Wo4: %x %x %x\n", (unsigned int) pointer,
 340                         (unsigned int) start_addr, *start_addr);
 341             }
 342             return 0;
 343
 344         case type_InstanceHeader:
 345             if (pointer_filter_verbose) {
 346                 fprintf(stderr,"*Wo5: %x %x %x\n", (unsigned int) pointer,
 347                         (unsigned int) start_addr, *start_addr);
 348             }
 349             return 0;
 350
 351             /* the valid other immediate pointer objects */
 352         case type_SimpleVector:
 353         case type_Ratio:
 354         case type_Complex:
 355 #ifdef type_ComplexSingleFloat
 356         case type_ComplexSingleFloat:
 357 #endif
 358 #ifdef type_ComplexDoubleFloat
 359         case type_ComplexDoubleFloat:
 360 #endif
 361 #ifdef type_ComplexLongFloat
 362         case type_ComplexLongFloat:
 363 #endif
 364         case type_SimpleArray:
 365         case type_ComplexString:
 366         case type_ComplexBitVector:
 367         case type_ComplexVector:
 368         case type_ComplexArray:
 369         case type_ValueCellHeader:
 370         case type_SymbolHeader:
 371         case type_Fdefn:
 372         case type_CodeHeader:
 373         case type_Bignum:
 374         case type_SingleFloat:
 375         case type_DoubleFloat:
 376 #ifdef type_LongFloat
 377         case type_LongFloat:
 378 #endif
 379         case type_SimpleString:
 380         case type_SimpleBitVector:
 381         case type_SimpleArrayUnsignedByte2:
 382         case type_SimpleArrayUnsignedByte4:
 383         case type_SimpleArrayUnsignedByte8:
 384         case type_SimpleArrayUnsignedByte16:
 385         case type_SimpleArrayUnsignedByte32:
 386 #ifdef type_SimpleArraySignedByte8
 387         case type_SimpleArraySignedByte8:
 388 #endif
 389 #ifdef type_SimpleArraySignedByte16
 390         case type_SimpleArraySignedByte16:
 391 #endif
 392 #ifdef type_SimpleArraySignedByte30
 393         case type_SimpleArraySignedByte30:
 394 #endif
 395 #ifdef type_SimpleArraySignedByte32
 396         case type_SimpleArraySignedByte32:
 397 #endif
 398         case type_SimpleArraySingleFloat:
 399         case type_SimpleArrayDoubleFloat:
 400 #ifdef type_SimpleArrayLongFloat
 401         case type_SimpleArrayLongFloat:
 402 #endif
 403 #ifdef type_SimpleArrayComplexSingleFloat
 404         case type_SimpleArrayComplexSingleFloat:
 405 #endif
 406 #ifdef type_SimpleArrayComplexDoubleFloat
 407         case type_SimpleArrayComplexDoubleFloat:
 408 #endif
 409 #ifdef type_SimpleArrayComplexLongFloat
 410         case type_SimpleArrayComplexLongFloat:
 411 #endif
 412         case type_Sap:
 413         case type_WeakPointer:
 414             break;
 415
 416         default:
 417             if (pointer_filter_verbose) {
 418                 fprintf(stderr,"*Wo6: %x %x %x\n", (unsigned int) pointer,
 419                         (unsigned int) start_addr, *start_addr);
 420             }
 421             return 0;
 422         }
 423         break;
 424     default:
 425         if (pointer_filter_verbose) {
 426             fprintf(stderr,"*W?: %x %x %x\n", (unsigned int) pointer,
 427                     (unsigned int) start_addr, *start_addr);
 428         }
 429         return 0;
 430     }
 431
 432     /* looks good */
 433     return 1;
 434 }
 435
 436 #define MAX_STACK_POINTERS 256
 437 lispobj *valid_stack_locations[MAX_STACK_POINTERS];
 438 unsigned int num_valid_stack_locations;
 439
 440 #define MAX_STACK_RETURN_ADDRESSES 128
 441 lispobj *valid_stack_ra_locations[MAX_STACK_RETURN_ADDRESSES];
 442 lispobj *valid_stack_ra_code_objects[MAX_STACK_RETURN_ADDRESSES];
 443 unsigned int num_valid_stack_ra_locations;
 444
 445 /* Identify valid stack slots. */
 446 static void
 447 setup_i386_stack_scav(lispobj *lowaddr, lispobj *base)
 448 {
 449     lispobj *sp = lowaddr;
 450     num_valid_stack_locations = 0;
 451     num_valid_stack_ra_locations = 0;
 452     for (sp = lowaddr; sp < base; sp++) {
 453         lispobj thing = *sp;
 454         /* Find the object start address */
 455         lispobj *start_addr = search_dynamic_space((void *)thing);
 456         if (start_addr) {
 457             /* We need to allow raw pointers into Code objects for
 458              * return addresses. This will also pick up pointers to
 459              * functions in code objects. */
 460             if (TypeOf(*start_addr) == type_CodeHeader) {
 461                 gc_assert(num_valid_stack_ra_locations <
 462                           MAX_STACK_RETURN_ADDRESSES);
 463                 valid_stack_ra_locations[num_valid_stack_ra_locations] = sp;
 464                 valid_stack_ra_code_objects[num_valid_stack_ra_locations++] =
 465                     (lispobj *)((int)start_addr + type_OtherPointer);
 466             } else {
 467                 if (valid_dynamic_space_pointer((void *)thing, start_addr)) {
 468                     gc_assert(num_valid_stack_locations < MAX_STACK_POINTERS);
 469                     valid_stack_locations[num_valid_stack_locations++] = sp;
 470                 }
 471             }
 472         }
 473     }
 474     if (pointer_filter_verbose) {
 475         fprintf(stderr, "number of valid stack pointers = %d\n",
 476                 num_valid_stack_locations);
 477         fprintf(stderr, "number of stack return addresses = %d\n",
 478                 num_valid_stack_ra_locations);
 479     }
 480 }
 481
 482 static void
 483 pscav_i386_stack(void)
 484 {
 485     int i;
 486
 487     for (i = 0; i < num_valid_stack_locations; i++)
 488         pscav(valid_stack_locations[i], 1, 0);
 489
 490     for (i = 0; i < num_valid_stack_ra_locations; i++) {
 491         lispobj code_obj = (lispobj)valid_stack_ra_code_objects[i];
 492         pscav(&code_obj, 1, 0);
 493         if (pointer_filter_verbose) {
 494             fprintf(stderr,"*C moved RA %x to %x; for code object %x to %x\n",
 495                     *valid_stack_ra_locations[i],
 496                     (int)(*valid_stack_ra_locations[i])
 497                     - ((int)valid_stack_ra_code_objects[i] - (int)code_obj),
 498                     (unsigned int) valid_stack_ra_code_objects[i], code_obj);
 499         }
 500         *valid_stack_ra_locations[i] =
 501             ((int)(*valid_stack_ra_locations[i])
 502              - ((int)valid_stack_ra_code_objects[i] - (int)code_obj));
 503     }
 504 }
 505 #endif
 506 #endif
 507
 508 \f
 509 static void
 510 pscav_later(lispobj *where, int count)
 511 {
 512     struct later *new;
 513
 514     if (count > LATERMAXCOUNT) {
 515         while (count > LATERMAXCOUNT) {
 516             pscav_later(where, LATERMAXCOUNT);
 517             count -= LATERMAXCOUNT;
 518             where += LATERMAXCOUNT;
 519         }
 520     }
 521     else {
 522         if (later_blocks == NULL || later_count == LATERBLOCKSIZE ||
 523             (later_count == LATERBLOCKSIZE-1 && count > 1)) {
 524             new  = (struct later *)malloc(sizeof(struct later));
 525             new->next = later_blocks;
 526             if (later_blocks && later_count < LATERBLOCKSIZE)
 527                 later_blocks->u[later_count].ptr = NULL;
 528             later_blocks = new;
 529             later_count = 0;
 530         }
 531
 532         if (count != 1)
 533             later_blocks->u[later_count++].count = count;
 534         later_blocks->u[later_count++].ptr = where;
 535     }
 536 }
 537
 538 static lispobj
 539 ptrans_boxed(lispobj thing, lispobj header, boolean constant)
 540 {
 541     int nwords;
 542     lispobj result, *new, *old;
 543
 544     nwords = 1 + HeaderValue(header);
 545
 546     /* Allocate it */
 547     old = (lispobj *)PTR(thing);
 548     if (constant) {
 549         new = read_only_free;
 550         read_only_free += CEILING(nwords, 2);
 551     }
 552     else {
 553         new = static_free;
 554         static_free += CEILING(nwords, 2);
 555     }
 556
 557     /* Copy it. */
 558     bcopy(old, new, nwords * sizeof(lispobj));
 559
 560     /* Deposit forwarding pointer. */
 561     result = (lispobj)new | LowtagOf(thing);
 562     *old = result;
 563
 564     /* Scavenge it. */
 565     pscav(new, nwords, constant);
 566
 567     return result;
 568 }
 569
 570 /* We need to look at the layout to see whether it is a pure structure
 571  * class, and only then can we transport as constant. If it is pure,
 572  * we can ALWAYS transport as a constant. */
 573 static lispobj
 574 ptrans_instance(lispobj thing, lispobj header, boolean constant)
 575 {
 576     lispobj layout = ((struct instance *)PTR(thing))->slots[0];
 577     lispobj pure = ((struct instance *)PTR(layout))->slots[15];
 578
 579     switch (pure) {
 580     case T:
 581         return (ptrans_boxed(thing, header, 1));
 582     case NIL:
 583         return (ptrans_boxed(thing, header, 0));
 584     case 0:
 585         {
 586             /* Substructure: special case for the COMPACT-INFO-ENVs,
 587              * where the instance may have a point to the dynamic
 588              * space placed into it (e.g. the cache-name slot), but
 589              * the lists and arrays at the time of a purify can be
 590              * moved to the RO space. */
 591             int nwords;
 592             lispobj result, *new, *old;
 593
 594             nwords = 1 + HeaderValue(header);
 595
 596             /* Allocate it */
 597             old = (lispobj *)PTR(thing);
 598             new = static_free;
 599             static_free += CEILING(nwords, 2);
 600
 601             /* Copy it. */
 602             bcopy(old, new, nwords * sizeof(lispobj));
 603
 604             /* Deposit forwarding pointer. */
 605             result = (lispobj)new | LowtagOf(thing);
 606             *old = result;
 607
 608             /* Scavenge it. */
 609             pscav(new, nwords, 1);
 610
 611             return result;
 612         }
 613     default:
 614         gc_abort();
 615         return NIL; /* dummy value: return something ... */
 616     }
 617 }
 618
 619 static lispobj
 620 ptrans_fdefn(lispobj thing, lispobj header)
 621 {
 622     int nwords;
 623     lispobj result, *new, *old, oldfn;
 624     struct fdefn *fdefn;
 625
 626     nwords = 1 + HeaderValue(header);
 627
 628     /* Allocate it */
 629     old = (lispobj *)PTR(thing);
 630     new = static_free;
 631     static_free += CEILING(nwords, 2);
 632
 633     /* Copy it. */
 634     bcopy(old, new, nwords * sizeof(lispobj));
 635
 636     /* Deposit forwarding pointer. */
 637     result = (lispobj)new | LowtagOf(thing);
 638     *old = result;
 639
 640     /* Scavenge the function. */
 641     fdefn = (struct fdefn *)new;
 642     oldfn = fdefn->function;
 643     pscav(&fdefn->function, 1, 0);
 644     if ((char *)oldfn + RAW_ADDR_OFFSET == fdefn->raw_addr)
 645         fdefn->raw_addr = (char *)fdefn->function + RAW_ADDR_OFFSET;
 646
 647     return result;
 648 }
 649
 650 static lispobj
 651 ptrans_unboxed(lispobj thing, lispobj header)
 652 {
 653     int nwords;
 654     lispobj result, *new, *old;
 655
 656     nwords = 1 + HeaderValue(header);
 657
 658     /* Allocate it */
 659     old = (lispobj *)PTR(thing);
 660     new = read_only_free;
 661     read_only_free += CEILING(nwords, 2);
 662
 663     /* Copy it. */
 664     bcopy(old, new, nwords * sizeof(lispobj));
 665
 666     /* Deposit forwarding pointer. */
 667     result = (lispobj)new | LowtagOf(thing);
 668     *old = result;
 669
 670     return result;
 671 }
 672
 673 static lispobj
 674 ptrans_vector(lispobj thing, int bits, int extra,
 675               boolean boxed, boolean constant)
 676 {
 677     struct vector *vector;
 678     int nwords;
 679     lispobj result, *new;
 680
 681     vector = (struct vector *)PTR(thing);
 682     nwords = 2 + (CEILING((fixnum_value(vector->length)+extra)*bits,32)>>5);
 683
 684     if (boxed && !constant) {
 685         new = static_free;
 686         static_free += CEILING(nwords, 2);
 687     }
 688     else {
 689         new = read_only_free;
 690         read_only_free += CEILING(nwords, 2);
 691     }
 692
 693     bcopy(vector, new, nwords * sizeof(lispobj));
 694
 695     result = (lispobj)new | LowtagOf(thing);
 696     vector->header = result;
 697
 698     if (boxed)
 699         pscav(new, nwords, constant);
 700
 701     return result;
 702 }
 703
 704 #ifdef __i386__
 705 static void
 706 apply_code_fixups_during_purify(struct code *old_code, struct code *new_code)
 707 {
 708   int nheader_words, ncode_words, nwords;
 709   void  *constants_start_addr, *constants_end_addr;
 710   void  *code_start_addr, *code_end_addr;
 711   lispobj fixups = NIL;
 712   unsigned  displacement = (unsigned)new_code - (unsigned)old_code;
 713   struct vector *fixups_vector;
 714
 715   /* Byte compiled code has no fixups. The trace table offset will be
 716    * a fixnum if it's x86 compiled code - check. */
 717   if (new_code->trace_table_offset & 0x3)
 718     return;
 719
 720   /* Else it's x86 machine code. */
 721   ncode_words = fixnum_value(new_code->code_size);
 722   nheader_words = HeaderValue(*(lispobj *)new_code);
 723   nwords = ncode_words + nheader_words;
 724
 725   constants_start_addr = (void *)new_code + 5*4;
 726   constants_end_addr = (void *)new_code + nheader_words*4;
 727   code_start_addr = (void *)new_code + nheader_words*4;
 728   code_end_addr = (void *)new_code + nwords*4;
 729
 730   /* The first constant should be a pointer to the fixups for this
 731    * code objects. Check. */
 732   fixups = new_code->constants[0];
 733
 734   /* It will be 0 or the unbound-marker if there are no fixups, and
 735    * will be an other-pointer to a vector if it is valid. */
 736   if ((fixups==0) || (fixups==type_UnboundMarker) || !Pointerp(fixups)) {
 737 #ifdef GENCGC
 738     /* Check for a possible errors. */
 739     sniff_code_object(new_code,displacement);
 740 #endif
 741     return;
 742   }
 743
 744   fixups_vector = (struct vector *)PTR(fixups);
 745
 746   /* Could be pointing to a forwarding pointer. */
 747   if (Pointerp(fixups) && (dynamic_pointer_p(fixups))
 748       && forwarding_pointer_p(*(lispobj *)fixups_vector)) {
 749     /* If so then follow it. */
 750     fixups_vector = (struct vector *)PTR(*(lispobj *)fixups_vector);
 751   }
 752
 753   if (TypeOf(fixups_vector->header) == type_SimpleArrayUnsignedByte32) {
 754     /* We got the fixups for the code block. Now work through the vector,
 755      * and apply a fixup at each address. */
 756     int length = fixnum_value(fixups_vector->length);
 757     int i;
 758     for (i=0; i<length; i++) {
 759       unsigned offset = fixups_vector->data[i];
 760       /* Now check the current value of offset. */
 761       unsigned  old_value = *(unsigned *)((unsigned)code_start_addr + offset);
 762
 763       /* If it's within the old_code object then it must be an
 764        * absolute fixup (relative ones are not saved) */
 765       if ((old_value>=(unsigned)old_code)
 766           && (old_value<((unsigned)old_code + nwords*4)))
 767         /* So add the dispacement. */
 768         *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 769           + displacement;
 770       else
 771         /* It is outside the old code object so it must be a relative
 772          * fixup (absolute fixups are not saved). So subtract the
 773          * displacement. */
 774         *(unsigned *)((unsigned)code_start_addr + offset) = old_value
 775           - displacement;
 776     }
 777   }
 778
 779   /* No longer need the fixups. */
 780   new_code->constants[0] = 0;
 781
 782 #ifdef GENCGC
 783   /* Check for possible errors. */
 784   sniff_code_object(new_code,displacement);
 785 #endif
 786 }
 787 #endif
 788
 789 static lispobj
 790 ptrans_code(lispobj thing)
 791 {
 792     struct code *code, *new;
 793     int nwords;
 794     lispobj func, result;
 795
 796     code = (struct code *)PTR(thing);
 797     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
 798
 799     new = (struct code *)read_only_free;
 800     read_only_free += CEILING(nwords, 2);
 801
 802     bcopy(code, new, nwords * sizeof(lispobj));
 803
 804 #ifdef __i386__
 805     apply_code_fixups_during_purify(code,new);
 806 #endif
 807
 808     result = (lispobj)new | type_OtherPointer;
 809
 810     /* Stick in a forwarding pointer for the code object. */
 811     *(lispobj *)code = result;
 812
 813     /* Put in forwarding pointers for all the functions. */
 814     for (func = code->entry_points;
 815          func != NIL;
 816          func = ((struct function *)PTR(func))->next) {
 817
 818         gc_assert(LowtagOf(func) == type_FunctionPointer);
 819
 820         *(lispobj *)PTR(func) = result + (func - thing);
 821     }
 822
 823     /* Arrange to scavenge the debug info later. */
 824     pscav_later(&new->debug_info, 1);
 825
 826     if(new->trace_table_offset & 0x3)
 827 #if 0
 828       pscav(&new->trace_table_offset, 1, 0);
 829 #else
 830       new->trace_table_offset = NIL; /* limit lifetime */
 831 #endif
 832
 833     /* Scavenge the constants. */
 834     pscav(new->constants, HeaderValue(new->header)-5, 1);
 835
 836     /* Scavenge all the functions. */
 837     pscav(&new->entry_points, 1, 1);
 838     for (func = new->entry_points;
 839          func != NIL;
 840          func = ((struct function *)PTR(func))->next) {
 841         gc_assert(LowtagOf(func) == type_FunctionPointer);
 842         gc_assert(!dynamic_pointer_p(func));
 843
 844 #ifdef __i386__
 845         /* Temporarly convert the self pointer to a real function
 846            pointer. */
 847         ((struct function *)PTR(func))->self -= RAW_ADDR_OFFSET;
 848 #endif
 849         pscav(&((struct function *)PTR(func))->self, 2, 1);
 850 #ifdef __i386__
 851         ((struct function *)PTR(func))->self += RAW_ADDR_OFFSET;
 852 #endif
 853         pscav_later(&((struct function *)PTR(func))->name, 3);
 854     }
 855
 856     return result;
 857 }
 858
 859 static lispobj
 860 ptrans_func(lispobj thing, lispobj header)
 861 {
 862     int nwords;
 863     lispobj code, *new, *old, result;
 864     struct function *function;
 865
 866     /* Thing can either be a function header, a closure function
 867      * header, a closure, or a funcallable-instance. If it's a closure
 868      * or a funcallable-instance, we do the same as ptrans_boxed.
 869      * Otherwise we have to do something strange, 'cause it is buried
 870      * inside a code object. */
 871
 872     if (TypeOf(header) == type_FunctionHeader ||
 873         TypeOf(header) == type_ClosureFunctionHeader) {
 874
 875         /* We can only end up here if the code object has not been
 876          * scavenged, because if it had been scavenged, forwarding pointers
 877          * would have been left behind for all the entry points. */
 878
 879         function = (struct function *)PTR(thing);
 880         code = (PTR(thing)-(HeaderValue(function->header)*sizeof(lispobj))) |
 881             type_OtherPointer;
 882
 883         /* This will cause the function's header to be replaced with a
 884          * forwarding pointer. */
 885         ptrans_code(code);
 886
 887         /* So we can just return that. */
 888         return function->header;
 889     }
 890     else {
 891         /* It's some kind of closure-like thing. */
 892         nwords = 1 + HeaderValue(header);
 893         old = (lispobj *)PTR(thing);
 894
 895         /* Allocate the new one. */
 896         if (TypeOf(header) == type_FuncallableInstanceHeader) {
 897             /* FINs *must* not go in read_only space. */
 898             new = static_free;
 899             static_free += CEILING(nwords, 2);
 900         }
 901         else {
 902             /* Closures can always go in read-only space, 'cause they
 903              * never change. */
 904
 905             new = read_only_free;
 906             read_only_free += CEILING(nwords, 2);
 907         }
 908         /* Copy it. */
 909         bcopy(old, new, nwords * sizeof(lispobj));
 910
 911         /* Deposit forwarding pointer. */
 912         result = (lispobj)new | LowtagOf(thing);
 913         *old = result;
 914
 915         /* Scavenge it. */
 916         pscav(new, nwords, 0);
 917
 918         return result;
 919     }
 920 }
 921
 922 static lispobj
 923 ptrans_returnpc(lispobj thing, lispobj header)
 924 {
 925     lispobj code, new;
 926
 927     /* Find the corresponding code object. */
 928     code = thing - HeaderValue(header)*sizeof(lispobj);
 929
 930     /* Make sure it's been transported. */
 931     new = *(lispobj *)PTR(code);
 932     if (!forwarding_pointer_p(new))
 933         new = ptrans_code(code);
 934
 935     /* Maintain the offset: */
 936     return new + (thing - code);
 937 }
 938
 939 #define WORDS_PER_CONS CEILING(sizeof(struct cons) / sizeof(lispobj), 2)
 940
 941 static lispobj
 942 ptrans_list(lispobj thing, boolean constant)
 943 {
 944     struct cons *old, *new, *orig;
 945     int length;
 946
 947     if (constant)
 948         orig = (struct cons *)read_only_free;
 949     else
 950         orig = (struct cons *)static_free;
 951     length = 0;
 952
 953     do {
 954         /* Allocate a new cons cell. */
 955         old = (struct cons *)PTR(thing);
 956         if (constant) {
 957             new = (struct cons *)read_only_free;
 958             read_only_free += WORDS_PER_CONS;
 959         }
 960         else {
 961             new = (struct cons *)static_free;
 962             static_free += WORDS_PER_CONS;
 963         }
 964
 965         /* Copy the cons cell and keep a pointer to the cdr. */
 966         new->car = old->car;
 967         thing = new->cdr = old->cdr;
 968
 969         /* Set up the forwarding pointer. */
 970         *(lispobj *)old = ((lispobj)new) | type_ListPointer;
 971
 972         /* And count this cell. */
 973         length++;
 974     } while (LowtagOf(thing) == type_ListPointer &&
 975              dynamic_pointer_p(thing) &&
 976              !(forwarding_pointer_p(*(lispobj *)PTR(thing))));
 977
 978     /* Scavenge the list we just copied. */
 979     pscav((lispobj *)orig, length * WORDS_PER_CONS, constant);
 980
 981     return ((lispobj)orig) | type_ListPointer;
 982 }
 983
 984 static lispobj
 985 ptrans_otherptr(lispobj thing, lispobj header, boolean constant)
 986 {
 987     switch (TypeOf(header)) {
 988       case type_Bignum:
 989       case type_SingleFloat:
 990       case type_DoubleFloat:
 991 #ifdef type_LongFloat
 992       case type_LongFloat:
 993 #endif
 994 #ifdef type_ComplexSingleFloat
 995       case type_ComplexSingleFloat:
 996 #endif
 997 #ifdef type_ComplexDoubleFloat
 998       case type_ComplexDoubleFloat:
 999 #endif
1000 #ifdef type_ComplexLongFloat
1001       case type_ComplexLongFloat:
1002 #endif
1003       case type_Sap:
1004         return ptrans_unboxed(thing, header);
1005
1006       case type_Ratio:
1007       case type_Complex:
1008       case type_SimpleArray:
1009       case type_ComplexString:
1010       case type_ComplexVector:
1011       case type_ComplexArray:
1012         return ptrans_boxed(thing, header, constant);
1013
1014       case type_ValueCellHeader:
1015       case type_WeakPointer:
1016         return ptrans_boxed(thing, header, 0);
1017
1018       case type_SymbolHeader:
1019         return ptrans_boxed(thing, header, 0);
1020
1021       case type_SimpleString:
1022         return ptrans_vector(thing, 8, 1, 0, constant);
1023
1024       case type_SimpleBitVector:
1025         return ptrans_vector(thing, 1, 0, 0, constant);
1026
1027       case type_SimpleVector:
1028         return ptrans_vector(thing, 32, 0, 1, constant);
1029
1030       case type_SimpleArrayUnsignedByte2:
1031         return ptrans_vector(thing, 2, 0, 0, constant);
1032
1033       case type_SimpleArrayUnsignedByte4:
1034         return ptrans_vector(thing, 4, 0, 0, constant);
1035
1036       case type_SimpleArrayUnsignedByte8:
1037 #ifdef type_SimpleArraySignedByte8
1038       case type_SimpleArraySignedByte8:
1039 #endif
1040         return ptrans_vector(thing, 8, 0, 0, constant);
1041
1042       case type_SimpleArrayUnsignedByte16:
1043 #ifdef type_SimpleArraySignedByte16
1044       case type_SimpleArraySignedByte16:
1045 #endif
1046         return ptrans_vector(thing, 16, 0, 0, constant);
1047
1048       case type_SimpleArrayUnsignedByte32:
1049 #ifdef type_SimpleArraySignedByte30
1050       case type_SimpleArraySignedByte30:
1051 #endif
1052 #ifdef type_SimpleArraySignedByte32
1053       case type_SimpleArraySignedByte32:
1054 #endif
1055         return ptrans_vector(thing, 32, 0, 0, constant);
1056
1057       case type_SimpleArraySingleFloat:
1058         return ptrans_vector(thing, 32, 0, 0, constant);
1059
1060       case type_SimpleArrayDoubleFloat:
1061         return ptrans_vector(thing, 64, 0, 0, constant);
1062
1063 #ifdef type_SimpleArrayLongFloat
1064       case type_SimpleArrayLongFloat:
1065 #ifdef __i386__
1066         return ptrans_vector(thing, 96, 0, 0, constant);
1067 #endif
1068 #ifdef sparc
1069         return ptrans_vector(thing, 128, 0, 0, constant);
1070 #endif
1071 #endif
1072
1073 #ifdef type_SimpleArrayComplexSingleFloat
1074       case type_SimpleArrayComplexSingleFloat:
1075         return ptrans_vector(thing, 64, 0, 0, constant);
1076 #endif
1077
1078 #ifdef type_SimpleArrayComplexDoubleFloat
1079       case type_SimpleArrayComplexDoubleFloat:
1080         return ptrans_vector(thing, 128, 0, 0, constant);
1081 #endif
1082
1083 #ifdef type_SimpleArrayComplexLongFloat
1084       case type_SimpleArrayComplexLongFloat:
1085 #ifdef __i386__
1086         return ptrans_vector(thing, 192, 0, 0, constant);
1087 #endif
1088 #ifdef sparc
1089         return ptrans_vector(thing, 256, 0, 0, constant);
1090 #endif
1091 #endif
1092
1093       case type_CodeHeader:
1094         return ptrans_code(thing);
1095
1096       case type_ReturnPcHeader:
1097         return ptrans_returnpc(thing, header);
1098
1099       case type_Fdefn:
1100         return ptrans_fdefn(thing, header);
1101
1102       default:
1103         /* Should only come across other pointers to the above stuff. */
1104         gc_abort();
1105         return NIL;
1106     }
1107 }
1108
1109 static int
1110 pscav_fdefn(struct fdefn *fdefn)
1111 {
1112     boolean fix_func;
1113
1114     fix_func = ((char *)(fdefn->function+RAW_ADDR_OFFSET) == fdefn->raw_addr);
1115     pscav(&fdefn->name, 1, 1);
1116     pscav(&fdefn->function, 1, 0);
1117     if (fix_func)
1118         fdefn->raw_addr = (char *)(fdefn->function + RAW_ADDR_OFFSET);
1119     return sizeof(struct fdefn) / sizeof(lispobj);
1120 }
1121
1122 #ifdef __i386__
1123 /* now putting code objects in static space */
1124 static int
1125 pscav_code(struct code*code)
1126 {
1127     int nwords;
1128     lispobj func;
1129     nwords = HeaderValue(code->header) + fixnum_value(code->code_size);
1130
1131     /* pw--The trace_table_offset slot can contain a list pointer. This
1132      * occurs when the code object is a top level form that initializes
1133      * a byte-compiled function. The fact that PURIFY was ignoring this
1134      * slot may be a bug unrelated to the x86 port, except that TLF's
1135      * normally become unreachable after the loader calls them and
1136      * won't be seen by PURIFY at all!! */
1137     if(code->trace_table_offset & 0x3)
1138 #if 0
1139       pscav(&code->trace_table_offset, 1, 0);
1140 #else
1141       code->trace_table_offset = NIL; /* limit lifetime */
1142 #endif
1143
1144     /* Arrange to scavenge the debug info later. */
1145     pscav_later(&code->debug_info, 1);
1146
1147     /* Scavenge the constants. */
1148     pscav(code->constants, HeaderValue(code->header)-5, 1);
1149
1150     /* Scavenge all the functions. */
1151     pscav(&code->entry_points, 1, 1);
1152     for (func = code->entry_points;
1153          func != NIL;
1154          func = ((struct function *)PTR(func))->next) {
1155         gc_assert(LowtagOf(func) == type_FunctionPointer);
1156         gc_assert(!dynamic_pointer_p(func));
1157
1158 #ifdef __i386__
1159         /* Temporarly convert the self pointer to a real function
1160          * pointer. */
1161         ((struct function *)PTR(func))->self -= RAW_ADDR_OFFSET;
1162 #endif
1163         pscav(&((struct function *)PTR(func))->self, 2, 1);
1164 #ifdef __i386__
1165         ((struct function *)PTR(func))->self += RAW_ADDR_OFFSET;
1166 #endif
1167         pscav_later(&((struct function *)PTR(func))->name, 3);
1168     }
1169
1170     return CEILING(nwords,2);
1171 }
1172 #endif
1173
1174 static lispobj *
1175 pscav(lispobj *addr, int nwords, boolean constant)
1176 {
1177     lispobj thing, *thingp, header;
1178     int count = 0; /* (0 = dummy init value to stop GCC warning) */
1179     struct vector *vector;
1180
1181     while (nwords > 0) {
1182         thing = *addr;
1183         if (Pointerp(thing)) {
1184             /* It's a pointer. Is it something we might have to move? */
1185             if (dynamic_pointer_p(thing)) {
1186                 /* Maybe. Have we already moved it? */
1187                 thingp = (lispobj *)PTR(thing);
1188                 header = *thingp;
1189                 if (Pointerp(header) && forwarding_pointer_p(header))
1190                     /* Yep, so just copy the forwarding pointer. */
1191                     thing = header;
1192                 else {
1193                     /* Nope, copy the object. */
1194                     switch (LowtagOf(thing)) {
1195                       case type_FunctionPointer:
1196                         thing = ptrans_func(thing, header);
1197                         break;
1198
1199                       case type_ListPointer:
1200                         thing = ptrans_list(thing, constant);
1201                         break;
1202
1203                       case type_InstancePointer:
1204                         thing = ptrans_instance(thing, header, constant);
1205                         break;
1206
1207                       case type_OtherPointer:
1208                         thing = ptrans_otherptr(thing, header, constant);
1209                         break;
1210
1211                       default:
1212                         /* It was a pointer, but not one of them? */
1213                         gc_abort();
1214                     }
1215                 }
1216                 *addr = thing;
1217             }
1218             count = 1;
1219         }
1220         else if (thing & 3) {
1221             /* It's an other immediate. Maybe the header for an unboxed */
1222             /* object. */
1223             switch (TypeOf(thing)) {
1224               case type_Bignum:
1225               case type_SingleFloat:
1226               case type_DoubleFloat:
1227 #ifdef type_LongFloat
1228               case type_LongFloat:
1229 #endif
1230               case type_Sap:
1231                 /* It's an unboxed simple object. */
1232                 count = HeaderValue(thing)+1;
1233                 break;
1234
1235               case type_SimpleVector:
1236                 if (HeaderValue(thing) == subtype_VectorValidHashing)
1237                     *addr = (subtype_VectorMustRehash<<type_Bits) |
1238                         type_SimpleVector;
1239                 count = 1;
1240                 break;
1241
1242               case type_SimpleString:
1243                 vector = (struct vector *)addr;
1244                 count = CEILING(NWORDS(fixnum_value(vector->length)+1,4)+2,2);
1245                 break;
1246
1247               case type_SimpleBitVector:
1248                 vector = (struct vector *)addr;
1249                 count = CEILING(NWORDS(fixnum_value(vector->length),32)+2,2);
1250                 break;
1251
1252               case type_SimpleArrayUnsignedByte2:
1253                 vector = (struct vector *)addr;
1254                 count = CEILING(NWORDS(fixnum_value(vector->length),16)+2,2);
1255                 break;
1256
1257               case type_SimpleArrayUnsignedByte4:
1258                 vector = (struct vector *)addr;
1259                 count = CEILING(NWORDS(fixnum_value(vector->length),8)+2,2);
1260                 break;
1261
1262               case type_SimpleArrayUnsignedByte8:
1263 #ifdef type_SimpleArraySignedByte8
1264               case type_SimpleArraySignedByte8:
1265 #endif
1266                 vector = (struct vector *)addr;
1267                 count = CEILING(NWORDS(fixnum_value(vector->length),4)+2,2);
1268                 break;
1269
1270               case type_SimpleArrayUnsignedByte16:
1271 #ifdef type_SimpleArraySignedByte16
1272               case type_SimpleArraySignedByte16:
1273 #endif
1274                 vector = (struct vector *)addr;
1275                 count = CEILING(NWORDS(fixnum_value(vector->length),2)+2,2);
1276                 break;
1277
1278               case type_SimpleArrayUnsignedByte32:
1279 #ifdef type_SimpleArraySignedByte30
1280               case type_SimpleArraySignedByte30:
1281 #endif
1282 #ifdef type_SimpleArraySignedByte32
1283               case type_SimpleArraySignedByte32:
1284 #endif
1285                 vector = (struct vector *)addr;
1286                 count = CEILING(fixnum_value(vector->length)+2,2);
1287                 break;
1288
1289               case type_SimpleArraySingleFloat:
1290                 vector = (struct vector *)addr;
1291                 count = CEILING(fixnum_value(vector->length)+2,2);
1292                 break;
1293
1294               case type_SimpleArrayDoubleFloat:
1295 #ifdef type_SimpleArrayComplexSingleFloat
1296               case type_SimpleArrayComplexSingleFloat:
1297 #endif
1298                 vector = (struct vector *)addr;
1299                 count = fixnum_value(vector->length)*2+2;
1300                 break;
1301
1302 #ifdef type_SimpleArrayLongFloat
1303               case type_SimpleArrayLongFloat:
1304                 vector = (struct vector *)addr;
1305 #ifdef __i386__
1306                 count = fixnum_value(vector->length)*3+2;
1307 #endif
1308 #ifdef sparc
1309                 count = fixnum_value(vector->length)*4+2;
1310 #endif
1311                 break;
1312 #endif
1313
1314 #ifdef type_SimpleArrayComplexDoubleFloat
1315               case type_SimpleArrayComplexDoubleFloat:
1316                 vector = (struct vector *)addr;
1317                 count = fixnum_value(vector->length)*4+2;
1318                 break;
1319 #endif
1320
1321 #ifdef type_SimpleArrayComplexLongFloat
1322               case type_SimpleArrayComplexLongFloat:
1323                 vector = (struct vector *)addr;
1324 #ifdef __i386__
1325                 count = fixnum_value(vector->length)*6+2;
1326 #endif
1327 #ifdef sparc
1328                 count = fixnum_value(vector->length)*8+2;
1329 #endif
1330                 break;
1331 #endif
1332
1333               case type_CodeHeader:
1334 #ifndef __i386__
1335                 gc_abort(); /* no code headers in static space */
1336 #else
1337                 count = pscav_code((struct code*)addr);
1338 #endif
1339                 break;
1340
1341               case type_FunctionHeader:
1342               case type_ClosureFunctionHeader:
1343               case type_ReturnPcHeader:
1344                 /* We should never hit any of these, 'cause they occur
1345                  * buried in the middle of code objects. */
1346                 gc_abort();
1347                 break;
1348
1349 #ifdef __i386__
1350               case type_ClosureHeader:
1351               case type_FuncallableInstanceHeader:
1352               case type_ByteCodeFunction:
1353               case type_ByteCodeClosure:
1354                 /* The function self pointer needs special care on the
1355                  * x86 because it is the real entry point. */
1356                 {
1357                   lispobj fun = ((struct closure *)addr)->function
1358                     - RAW_ADDR_OFFSET;
1359                   pscav(&fun, 1, constant);
1360                   ((struct closure *)addr)->function = fun + RAW_ADDR_OFFSET;
1361                 }
1362                 count = 2;
1363                 break;
1364 #endif
1365
1366               case type_WeakPointer:
1367                 /* Weak pointers get preserved during purify, 'cause I
1368                  * don't feel like figuring out how to break them. */
1369                 pscav(addr+1, 2, constant);
1370                 count = 4;
1371                 break;
1372
1373               case type_Fdefn:
1374                 /* We have to handle fdefn objects specially, so we
1375                  * can fix up the raw function address. */
1376                 count = pscav_fdefn((struct fdefn *)addr);
1377                 break;
1378
1379               default:
1380                 count = 1;
1381                 break;
1382             }
1383         }
1384         else {
1385             /* It's a fixnum. */
1386             count = 1;
1387         }
1388
1389         addr += count;
1390         nwords -= count;
1391     }
1392
1393     return addr;
1394 }
1395
1396 int
1397 purify(lispobj static_roots, lispobj read_only_roots)
1398 {
1399     lispobj *clean;
1400     int count, i;
1401     struct later *laters, *next;
1402
1403 #ifdef PRINTNOISE
1404     printf("[doing purification:");
1405     fflush(stdout);
1406 #endif
1407
1408     if (fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX)) != 0) {
1409         /* FIXME: 1. What does this mean? 2. It shouldn't be reporting
1410          * its error simply by a. printing a string b. to stdout instead
1411          * of stderr. */
1412         printf(" Ack! Can't purify interrupt contexts. ");
1413         fflush(stdout);
1414         return 0;
1415     }
1416
1417 #if defined(ibmrt) || defined(__i386__)
1418     dynamic_space_free_pointer =
1419       (lispobj*)SymbolValue(ALLOCATION_POINTER);
1420 #endif
1421
1422     read_only_end = read_only_free =
1423         (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER);
1424     static_end = static_free =
1425         (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER);
1426
1427 #ifdef PRINTNOISE
1428     printf(" roots");
1429     fflush(stdout);
1430 #endif
1431
1432 #ifdef GENCGC
1433     gc_assert((lispobj *)CONTROL_STACK_END > ((&read_only_roots)+1));
1434     setup_i386_stack_scav(((&static_roots)-2), (lispobj *)CONTROL_STACK_END);
1435 #endif
1436
1437     pscav(&static_roots, 1, 0);
1438     pscav(&read_only_roots, 1, 1);
1439
1440 #ifdef PRINTNOISE
1441     printf(" handlers");
1442     fflush(stdout);
1443 #endif
1444     pscav((lispobj *) interrupt_handlers,
1445           sizeof(interrupt_handlers) / sizeof(lispobj),
1446           0);
1447
1448 #ifdef PRINTNOISE
1449     printf(" stack");
1450     fflush(stdout);
1451 #endif
1452 #ifndef __i386__
1453     pscav((lispobj *)CONTROL_STACK_START,
1454           current_control_stack_pointer - (lispobj *)CONTROL_STACK_START,
1455           0);
1456 #else
1457 #ifdef GENCGC
1458     pscav_i386_stack();
1459 #endif
1460 #ifdef WANT_CGC
1461     gc_assert((lispobj *)control_stack_end > ((&read_only_roots)+1));
1462     carefully_pscav_stack(((&read_only_roots)+1),
1463                           (lispobj *)CONTROL_STACK_END);
1464 #endif
1465 #endif
1466
1467 #ifdef PRINTNOISE
1468     printf(" bindings");
1469     fflush(stdout);
1470 #endif
1471 #if !defined(ibmrt) && !defined(__i386__)
1472     pscav( (lispobj *)BINDING_STACK_START,
1473           (lispobj *)current_binding_stack_pointer - (lispobj *)BINDING_STACK_START,
1474           0);
1475 #else
1476     pscav( (lispobj *)BINDING_STACK_START,
1477           (lispobj *)SymbolValue(BINDING_STACK_POINTER) -
1478           (lispobj *)BINDING_STACK_START,
1479           0);
1480 #endif
1481
1482 #ifdef SCAVENGE_READ_ONLY_SPACE
1483     if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != type_UnboundMarker
1484         && SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
1485       unsigned  read_only_space_size =
1486           (lispobj *)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
1487           (lispobj *)READ_ONLY_SPACE_START;
1488       fprintf(stderr,
1489               "scavenging read only space: %d bytes\n",
1490               read_only_space_size * sizeof(lispobj));
1491       pscav( (lispobj *)READ_ONLY_SPACE_START, read_only_space_size, 0);
1492     }
1493 #endif
1494
1495 #ifdef PRINTNOISE
1496     printf(" static");
1497     fflush(stdout);
1498 #endif
1499     clean = (lispobj *)STATIC_SPACE_START;
1500     do {
1501         while (clean != static_free)
1502             clean = pscav(clean, static_free - clean, 0);
1503         laters = later_blocks;
1504         count = later_count;
1505         later_blocks = NULL;
1506         later_count = 0;
1507         while (laters != NULL) {
1508             for (i = 0; i < count; i++) {
1509                 if (laters->u[i].count == 0) {
1510                     ;
1511                 } else if (laters->u[i].count <= LATERMAXCOUNT) {
1512                     pscav(laters->u[i+1].ptr, laters->u[i].count, 1);
1513                     i++;
1514                 } else {
1515                     pscav(laters->u[i].ptr, 1, 1);
1516                 }
1517             }
1518             next = laters->next;
1519             free(laters);
1520             laters = next;
1521             count = LATERBLOCKSIZE;
1522         }
1523     } while (clean != static_free || later_blocks != NULL);
1524
1525 #ifdef PRINTNOISE
1526     printf(" cleanup");
1527     fflush(stdout);
1528 #endif
1529
1530 #if defined(WANT_CGC) && defined(X86_CGC_ACTIVE_P)
1531     if(SymbolValue(X86_CGC_ACTIVE_P) != T) {
1532         os_zero((os_vm_address_t) DYNAMIC_SPACE_START,
1533                 (os_vm_size_t) DYNAMIC_SPACE_SIZE);
1534     }
1535 #else
1536     os_zero((os_vm_address_t) current_dynamic_space,
1537             (os_vm_size_t) DYNAMIC_SPACE_SIZE);
1538 #endif
1539
1540     /* Zero the stack. Note that the stack is also zeroed by SUB-GC
1541      * calling SCRUB-CONTROL-STACK - this zeros the stack on the x86. */
1542 #ifndef __i386__
1543     os_zero((os_vm_address_t) current_control_stack_pointer,
1544             (os_vm_size_t) (CONTROL_STACK_SIZE -
1545                             ((current_control_stack_pointer -
1546                               (lispobj *)CONTROL_STACK_START) *
1547                              sizeof(lispobj))));
1548 #endif
1549
1550 #if defined(WANT_CGC) && defined(STATIC_BLUE_BAG)
1551     {
1552       lispobj bag = SymbolValue(STATIC_BLUE_BAG);
1553       struct cons*cons = (struct cons*)static_free;
1554       struct cons*pair = cons + 1;
1555       static_free += 2*WORDS_PER_CONS;
1556       if(bag == type_UnboundMarker)
1557         bag = NIL;
1558       cons->cdr = bag;
1559       cons->car = (lispobj)pair | type_ListPointer;
1560       pair->car = (lispobj)static_end;
1561       pair->cdr = (lispobj)static_free;
1562       bag = (lispobj)cons | type_ListPointer;
1563       SetSymbolValue(STATIC_BLUE_BAG, bag);
1564     }
1565 #endif
1566
1567     /* It helps to update the heap free pointers so that free_heap can
1568      * verify after it's done. */
1569     SetSymbolValue(READ_ONLY_SPACE_FREE_POINTER, (lispobj)read_only_free);
1570     SetSymbolValue(STATIC_SPACE_FREE_POINTER, (lispobj)static_free);
1571
1572 #if !defined(ibmrt) && !defined(__i386__)
1573     dynamic_space_free_pointer = current_dynamic_space;
1574 #else
1575 #if defined(WANT_CGC) && defined(X86_CGC_ACTIVE_P)
1576     /* X86 using CGC */
1577     if(SymbolValue(X86_CGC_ACTIVE_P) != T)
1578         SetSymbolValue(ALLOCATION_POINTER, (lispobj)DYNAMIC_SPACE_START);
1579     else
1580         cgc_free_heap();
1581 #else
1582 #if defined GENCGC
1583     gc_free_heap();
1584 #else
1585     /* ibmrt using GC */
1586     SetSymbolValue(ALLOCATION_POINTER, (lispobj)DYNAMIC_SPACE_START);
1587 #endif
1588 #endif
1589 #endif
1590
1591 #ifdef PRINTNOISE
1592     printf(" done]\n");
1593     fflush(stdout);
1594 #endif
1595
1596     return 0;
1597 }