boehm-gc/os_dep.c

   1 /*
   2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
   3  * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
   4  * Copyright (c) 1996-1999 by Silicon Graphics.  All rights reserved.
   5  * Copyright (c) 1999 by Hewlett-Packard Company.  All rights reserved.
   6  *
   7  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   8  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   9  *
  10  * Permission is hereby granted to use or copy this program
  11  * for any purpose,  provided the above notices are retained on all copies.
  12  * Permission to modify the code and to distribute modified code is granted,
  13  * provided the above notices are retained, and a notice that the code was
  14  * modified is included with the above copyright notice.
  15  */
  16
  17 # include "gc_priv.h"
  18
  19 # if defined(LINUX) && !defined(POWERPC)
  20 #   include <linux/version.h>
  21 #   if (LINUX_VERSION_CODE <= 0x10400)
  22       /* Ugly hack to get struct sigcontext_struct definition.  Required      */
  23       /* for some early 1.3.X releases.  Will hopefully go away soon. */
  24       /* in some later Linux releases, asm/sigcontext.h may have to   */
  25       /* be included instead.                                         */
  26 #     define __KERNEL__
  27 #     include <asm/signal.h>
  28 #     undef __KERNEL__
  29 #   else
  30       /* Kernels prior to 2.1.1 defined struct sigcontext_struct instead of */
  31       /* struct sigcontext.  libc6 (glibc2) uses "struct sigcontext" in     */
  32       /* prototypes, so we have to include the top-level sigcontext.h to    */
  33       /* make sure the former gets defined to be the latter if appropriate. */
  34 #     include <features.h>
  35 #     if 2 <= __GLIBC__
  36 #       if 2 == __GLIBC__ && 0 == __GLIBC_MINOR__
  37           /* glibc 2.1 no longer has sigcontext.h.  But signal.h        */
  38           /* has the right declaration for glibc 2.1.                   */
  39 #         include <sigcontext.h>
  40 #       endif /* 0 == __GLIBC_MINOR__ */
  41 #     else /* not 2 <= __GLIBC__ */
  42         /* libc5 doesn't have <sigcontext.h>: go directly with the kernel   */
  43         /* one.  Check LINUX_VERSION_CODE to see which we should reference. */
  44 #       include <asm/sigcontext.h>
  45 #     endif /* 2 <= __GLIBC__ */
  46 #   endif
  47 # endif
  48 # if !defined(OS2) && !defined(PCR) && !defined(AMIGA) && !defined(MACOS)
  49 #   include <sys/types.h>
  50 #   if !defined(MSWIN32) && !defined(SUNOS4)
  51 #       include <unistd.h>
  52 #   endif
  53 # endif
  54
  55 # include <stdio.h>
  56 # include <signal.h>
  57
  58 /* Blatantly OS dependent routines, except for those that are related   */
  59 /* to dynamic loading.                                                  */
  60
  61 # if !defined(THREADS) && !defined(STACKBOTTOM) && defined(HEURISTIC2)
  62 #   define NEED_FIND_LIMIT
  63 # endif
  64
  65 # if defined(IRIX_THREADS) || defined(HPUX_THREADS)
  66 #   define NEED_FIND_LIMIT
  67 # endif
  68
  69 # if (defined(SUNOS4) & defined(DYNAMIC_LOADING)) && !defined(PCR)
  70 #   define NEED_FIND_LIMIT
  71 # endif
  72
  73 # if (defined(SVR4) || defined(AUX) || defined(DGUX)) && !defined(PCR)
  74 #   define NEED_FIND_LIMIT
  75 # endif
  76
  77 # if defined(LINUX) && \
  78      (defined(SPARC) || defined(ALPHA) || defined(IA64))
  79 #   define NEED_FIND_LIMIT
  80 # endif
  81
  82 #ifdef NEED_FIND_LIMIT
  83 #   include <setjmp.h>
  84 #endif
  85
  86 #ifdef FREEBSD
  87 #  include <machine/trap.h>
  88 #endif
  89
  90 #ifdef AMIGA
  91 # include <proto/exec.h>
  92 # include <proto/dos.h>
  93 # include <dos/dosextens.h>
  94 # include <workbench/startup.h>
  95 #endif
  96
  97 #ifdef MSWIN32
  98 # define WIN32_LEAN_AND_MEAN
  99 # define NOSERVICE
 100 # include <windows.h>
 101 #endif
 102
 103 #ifdef MACOS
 104 # include <Processes.h>
 105 #endif
 106
 107 #ifdef IRIX5
 108 # include <sys/uio.h>
 109 # include <malloc.h>   /* for locking */
 110 #endif
 111 #ifdef USE_MMAP
 112 # include <sys/types.h>
 113 # include <sys/mman.h>
 114 # include <sys/stat.h>
 115 # include <fcntl.h>
 116 #endif
 117
 118 #ifdef SUNOS5SIGS
 119 # include <sys/siginfo.h>
 120 # undef setjmp
 121 # undef longjmp
 122 # define setjmp(env) sigsetjmp(env, 1)
 123 # define longjmp(env, val) siglongjmp(env, val)
 124 # define jmp_buf sigjmp_buf
 125 #endif
 126
 127 #ifdef DJGPP
 128   /* Apparently necessary for djgpp 2.01.  May casuse problems with     */
 129   /* other versions.                                                    */
 130   typedef long unsigned int caddr_t;
 131 #endif
 132
 133 #ifdef PCR
 134 # include "il/PCR_IL.h"
 135 # include "th/PCR_ThCtl.h"
 136 # include "mm/PCR_MM.h"
 137 #endif
 138
 139 #if !defined(NO_EXECUTE_PERMISSION)
 140 # define OPT_PROT_EXEC PROT_EXEC
 141 #else
 142 # define OPT_PROT_EXEC 0
 143 #endif
 144
 145 #if defined(LINUX) && (defined(SPARC) || defined(ALPHA) || defined(IA64))
 146   /* The I386 case can be handled without a search.  The Alpha case     */
 147   /* used to be handled differently as well, but the rules changed      */
 148   /* for recent Linux versions.  This seems to be the easiest way to    */
 149   /* cover all versions.                                                */
 150   ptr_t GC_data_start;
 151
 152   extern char * GC_copyright[];  /* Any data symbol would do. */
 153
 154   void GC_init_linux_data_start()
 155   {
 156     extern ptr_t GC_find_limit();
 157
 158     GC_data_start = GC_find_limit((ptr_t)GC_copyright, FALSE);
 159   }
 160 #endif
 161
 162 # ifdef ECOS
 163
 164 # ifndef ECOS_GC_MEMORY_SIZE
 165 # define ECOS_GC_MEMORY_SIZE (448 * 1024)
 166 # endif /* ECOS_GC_MEMORY_SIZE */
 167
 168 // setjmp() function, as described in ANSI para 7.6.1.1
 169 #define setjmp( __env__ )  hal_setjmp( __env__ )
 170
 171 // FIXME: This is a simple way of allocating memory which is
 172 // compatible with ECOS early releases.  Later releases use a more
 173 // sophisticated means of allocating memory than this simple static
 174 // allocator, but this method is at least bound to work.
 175 static char memory[ECOS_GC_MEMORY_SIZE];
 176 static char *brk = memory;
 177
 178 static void *tiny_sbrk(ptrdiff_t increment)
 179 {
 180   void *p = brk;
 181
 182   brk += increment;
 183
 184   if (brk >  memory + sizeof memory)
 185     {
 186       brk -= increment;
 187       return NULL;
 188     }
 189
 190   return p;
 191 }
 192 #define sbrk tiny_sbrk
 193 # endif /* ECOS */
 194
 195 # ifdef OS2
 196
 197 # include <stddef.h>
 198
 199 # if !defined(__IBMC__) && !defined(__WATCOMC__) /* e.g. EMX */
 200
 201 struct exe_hdr {
 202     unsigned short      magic_number;
 203     unsigned short      padding[29];
 204     long                new_exe_offset;
 205 };
 206
 207 #define E_MAGIC(x)      (x).magic_number
 208 #define EMAGIC          0x5A4D
 209 #define E_LFANEW(x)     (x).new_exe_offset
 210
 211 struct e32_exe {
 212     unsigned char       magic_number[2];
 213     unsigned char       byte_order;
 214     unsigned char       word_order;
 215     unsigned long       exe_format_level;
 216     unsigned short      cpu;
 217     unsigned short      os;
 218     unsigned long       padding1[13];
 219     unsigned long       object_table_offset;
 220     unsigned long       object_count;
 221     unsigned long       padding2[31];
 222 };
 223
 224 #define E32_MAGIC1(x)   (x).magic_number[0]
 225 #define E32MAGIC1       'L'
 226 #define E32_MAGIC2(x)   (x).magic_number[1]
 227 #define E32MAGIC2       'X'
 228 #define E32_BORDER(x)   (x).byte_order
 229 #define E32LEBO         0
 230 #define E32_WORDER(x)   (x).word_order
 231 #define E32LEWO         0
 232 #define E32_CPU(x)      (x).cpu
 233 #define E32CPU286       1
 234 #define E32_OBJTAB(x)   (x).object_table_offset
 235 #define E32_OBJCNT(x)   (x).object_count
 236
 237 struct o32_obj {
 238     unsigned long       size;
 239     unsigned long       base;
 240     unsigned long       flags;
 241     unsigned long       pagemap;
 242     unsigned long       mapsize;
 243     unsigned long       reserved;
 244 };
 245
 246 #define O32_FLAGS(x)    (x).flags
 247 #define OBJREAD         0x0001L
 248 #define OBJWRITE        0x0002L
 249 #define OBJINVALID      0x0080L
 250 #define O32_SIZE(x)     (x).size
 251 #define O32_BASE(x)     (x).base
 252
 253 # else  /* IBM's compiler */
 254
 255 /* A kludge to get around what appears to be a header file bug */
 256 # ifndef WORD
 257 #   define WORD unsigned short
 258 # endif
 259 # ifndef DWORD
 260 #   define DWORD unsigned long
 261 # endif
 262
 263 # define EXE386 1
 264 # include <newexe.h>
 265 # include <exe386.h>
 266
 267 # endif  /* __IBMC__ */
 268
 269 # define INCL_DOSEXCEPTIONS
 270 # define INCL_DOSPROCESS
 271 # define INCL_DOSERRORS
 272 # define INCL_DOSMODULEMGR
 273 # define INCL_DOSMEMMGR
 274 # include <os2.h>
 275
 276
 277 /* Disable and enable signals during nontrivial allocations     */
 278
 279 void GC_disable_signals(void)
 280 {
 281     ULONG nest;
 282
 283     DosEnterMustComplete(&nest);
 284     if (nest != 1) ABORT("nested GC_disable_signals");
 285 }
 286
 287 void GC_enable_signals(void)
 288 {
 289     ULONG nest;
 290
 291     DosExitMustComplete(&nest);
 292     if (nest != 0) ABORT("GC_enable_signals");
 293 }
 294
 295
 296 # else
 297
 298 #  if !defined(PCR) && !defined(AMIGA) && !defined(MSWIN32) \
 299       && !defined(MACOS) && !defined(DJGPP) && !defined(DOS4GW) \
 300       && !defined(NO_SIGSET)
 301
 302 #   if defined(sigmask) && !defined(UTS4)
 303         /* Use the traditional BSD interface */
 304 #       define SIGSET_T int
 305 #       define SIG_DEL(set, signal) (set) &= ~(sigmask(signal))
 306 #       define SIG_FILL(set)  (set) = 0x7fffffff
 307           /* Setting the leading bit appears to provoke a bug in some   */
 308           /* longjmp implementations.  Most systems appear not to have  */
 309           /* a signal 32.                                               */
 310 #       define SIGSETMASK(old, new) (old) = sigsetmask(new)
 311 #   else
 312         /* Use POSIX/SYSV interface     */
 313 #       define SIGSET_T sigset_t
 314 #       define SIG_DEL(set, signal) sigdelset(&(set), (signal))
 315 #       define SIG_FILL(set) sigfillset(&set)
 316 #       define SIGSETMASK(old, new) sigprocmask(SIG_SETMASK, &(new), &(old))
 317 #   endif
 318
 319 static GC_bool mask_initialized = FALSE;
 320
 321 static SIGSET_T new_mask;
 322
 323 static SIGSET_T old_mask;
 324
 325 static SIGSET_T dummy;
 326
 327 #if defined(PRINTSTATS) && !defined(THREADS)
 328 # define CHECK_SIGNALS
 329   int GC_sig_disabled = 0;
 330 #endif
 331
 332 void GC_disable_signals()
 333 {
 334     if (!mask_initialized) {
 335         SIG_FILL(new_mask);
 336
 337         SIG_DEL(new_mask, SIGSEGV);
 338         SIG_DEL(new_mask, SIGILL);
 339         SIG_DEL(new_mask, SIGQUIT);
 340 #       ifdef SIGBUS
 341             SIG_DEL(new_mask, SIGBUS);
 342 #       endif
 343 #       ifdef SIGIOT
 344             SIG_DEL(new_mask, SIGIOT);
 345 #       endif
 346 #       ifdef SIGEMT
 347             SIG_DEL(new_mask, SIGEMT);
 348 #       endif
 349 #       ifdef SIGTRAP
 350             SIG_DEL(new_mask, SIGTRAP);
 351 #       endif
 352         mask_initialized = TRUE;
 353     }
 354 #   ifdef CHECK_SIGNALS
 355         if (GC_sig_disabled != 0) ABORT("Nested disables");
 356         GC_sig_disabled++;
 357 #   endif
 358     SIGSETMASK(old_mask,new_mask);
 359 }
 360
 361 void GC_enable_signals()
 362 {
 363 #   ifdef CHECK_SIGNALS
 364         if (GC_sig_disabled != 1) ABORT("Unmatched enable");
 365         GC_sig_disabled--;
 366 #   endif
 367     SIGSETMASK(dummy,old_mask);
 368 }
 369
 370 #  endif  /* !PCR */
 371
 372 # endif /*!OS/2 */
 373
 374 /* Ivan Demakov: simplest way (to me) */
 375 #if defined (DOS4GW) || defined (NO_SIGSET)
 376   void GC_disable_signals() { }
 377   void GC_enable_signals() { }
 378 #endif
 379
 380 /* Find the page size */
 381 word GC_page_size;
 382
 383 # ifdef MSWIN32
 384   void GC_setpagesize()
 385   {
 386     SYSTEM_INFO sysinfo;
 387
 388     GetSystemInfo(&sysinfo);
 389     GC_page_size = sysinfo.dwPageSize;
 390   }
 391
 392 # else
 393 #   if defined(MPROTECT_VDB) || defined(PROC_VDB) || defined(USE_MMAP) \
 394        || defined(USE_MUNMAP)
 395         void GC_setpagesize()
 396         {
 397             GC_page_size = GETPAGESIZE();
 398         }
 399 #   else
 400         /* It's acceptable to fake it. */
 401         void GC_setpagesize()
 402         {
 403             GC_page_size = HBLKSIZE;
 404         }
 405 #   endif
 406 # endif
 407
 408 /*
 409  * Find the base of the stack.
 410  * Used only in single-threaded environment.
 411  * With threads, GC_mark_roots needs to know how to do this.
 412  * Called with allocator lock held.
 413  */
 414 # ifdef MSWIN32
 415 # define is_writable(prot) ((prot) == PAGE_READWRITE \
 416                             || (prot) == PAGE_WRITECOPY \
 417                             || (prot) == PAGE_EXECUTE_READWRITE \
 418                             || (prot) == PAGE_EXECUTE_WRITECOPY)
 419 /* Return the number of bytes that are writable starting at p.  */
 420 /* The pointer p is assumed to be page aligned.                 */
 421 /* If base is not 0, *base becomes the beginning of the         */
 422 /* allocation region containing p.                              */
 423 word GC_get_writable_length(ptr_t p, ptr_t *base)
 424 {
 425     MEMORY_BASIC_INFORMATION buf;
 426     word result;
 427     word protect;
 428
 429     result = VirtualQuery(p, &buf, sizeof(buf));
 430     if (result != sizeof(buf)) ABORT("Weird VirtualQuery result");
 431     if (base != 0) *base = (ptr_t)(buf.AllocationBase);
 432     protect = (buf.Protect & ~(PAGE_GUARD | PAGE_NOCACHE));
 433     if (!is_writable(protect)) {
 434         return(0);
 435     }
 436     if (buf.State != MEM_COMMIT) return(0);
 437     return(buf.RegionSize);
 438 }
 439
 440 ptr_t GC_get_stack_base()
 441 {
 442     int dummy;
 443     ptr_t sp = (ptr_t)(&dummy);
 444     ptr_t trunc_sp = (ptr_t)((word)sp & ~(GC_page_size - 1));
 445     word size = GC_get_writable_length(trunc_sp, 0);
 446
 447     return(trunc_sp + size);
 448 }
 449
 450
 451 # else
 452
 453 # ifdef OS2
 454
 455 ptr_t GC_get_stack_base()
 456 {
 457     PTIB ptib;
 458     PPIB ppib;
 459
 460     if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
 461         GC_err_printf0("DosGetInfoBlocks failed\n");
 462         ABORT("DosGetInfoBlocks failed\n");
 463     }
 464     return((ptr_t)(ptib -> tib_pstacklimit));
 465 }
 466
 467 # else
 468
 469 # ifdef AMIGA
 470
 471 ptr_t GC_get_stack_base()
 472 {
 473     struct Process *proc = (struct Process*)SysBase->ThisTask;
 474
 475     /* Reference: Amiga Guru Book Pages: 42,567,574 */
 476     if (proc->pr_Task.tc_Node.ln_Type==NT_PROCESS
 477         && proc->pr_CLI != NULL) {
 478         /* first ULONG is StackSize */
 479         /*longPtr = proc->pr_ReturnAddr;
 480         size = longPtr[0];*/
 481
 482         return (char *)proc->pr_ReturnAddr + sizeof(ULONG);
 483     } else {
 484         return (char *)proc->pr_Task.tc_SPUpper;
 485     }
 486 }
 487
 488 #if 0 /* old version */
 489 ptr_t GC_get_stack_base()
 490 {
 491     extern struct WBStartup *_WBenchMsg;
 492     extern long __base;
 493     extern long __stack;
 494     struct Task *task;
 495     struct Process *proc;
 496     struct CommandLineInterface *cli;
 497     long size;
 498
 499     if ((task = FindTask(0)) == 0) {
 500         GC_err_puts("Cannot find own task structure\n");
 501         ABORT("task missing");
 502     }
 503     proc = (struct Process *)task;
 504     cli = BADDR(proc->pr_CLI);
 505
 506     if (_WBenchMsg != 0 || cli == 0) {
 507         size = (char *)task->tc_SPUpper - (char *)task->tc_SPLower;
 508     } else {
 509         size = cli->cli_DefaultStack * 4;
 510     }
 511     return (ptr_t)(__base + GC_max(size, __stack));
 512 }
 513 #endif /* 0 */
 514
 515 # else /* !AMIGA, !OS2, ... */
 516
 517 # ifdef NEED_FIND_LIMIT
 518   /* Some tools to implement HEURISTIC2 */
 519 #   define MIN_PAGE_SIZE 256    /* Smallest conceivable page size, bytes */
 520     /* static */ jmp_buf GC_jmp_buf;
 521
 522     /*ARGSUSED*/
 523     void GC_fault_handler(sig)
 524     int sig;
 525     {
 526         longjmp(GC_jmp_buf, 1);
 527     }
 528
 529 #   ifdef __STDC__
 530         typedef void (*handler)(int);
 531 #   else
 532         typedef void (*handler)();
 533 #   endif
 534
 535 #   if defined(SUNOS5SIGS) || defined(IRIX5) || defined(OSF1)
 536         static struct sigaction old_segv_act;
 537 #       if defined(_sigargs) || defined(HPUX) /* !Irix6.x */
 538             static struct sigaction old_bus_act;
 539 #       endif
 540 #   else
 541         static handler old_segv_handler, old_bus_handler;
 542 #   endif
 543
 544     void GC_setup_temporary_fault_handler()
 545     {
 546 # ifndef ECOS
 547 #       if defined(SUNOS5SIGS) || defined(IRIX5) || defined(OSF1)
 548           struct sigaction      act;
 549
 550           act.sa_handler        = GC_fault_handler;
 551           act.sa_flags          = SA_RESTART | SA_NODEFER;
 552           /* The presence of SA_NODEFER represents yet another gross    */
 553           /* hack.  Under Solaris 2.3, siglongjmp doesn't appear to     */
 554           /* interact correctly with -lthread.  We hide the confusion   */
 555           /* by making sure that signal handling doesn't affect the     */
 556           /* signal mask.                                               */
 557
 558           (void) sigemptyset(&act.sa_mask);
 559 #         ifdef IRIX_THREADS
 560                 /* Older versions have a bug related to retrieving and  */
 561                 /* and setting a handler at the same time.              */
 562                 (void) sigaction(SIGSEGV, 0, &old_segv_act);
 563                 (void) sigaction(SIGSEGV, &act, 0);
 564 #         else
 565                 (void) sigaction(SIGSEGV, &act, &old_segv_act);
 566 #               if defined(IRIX5) && defined(_sigargs) /* Irix 5.x, not 6.x */ \
 567                    || defined(HPUX)
 568                     /* Under Irix 5.x or HP/UX, we may get SIGBUS.      */
 569                     /* Pthreads doesn't exist under Irix 5.x, so we     */
 570                     /* don't have to worry in the threads case.         */
 571                     (void) sigaction(SIGBUS, &act, &old_bus_act);
 572 #               endif
 573 #         endif /* IRIX_THREADS */
 574 #       else
 575           old_segv_handler = signal(SIGSEGV, GC_fault_handler);
 576 #         ifdef SIGBUS
 577             old_bus_handler = signal(SIGBUS, GC_fault_handler);
 578 #         endif
 579 #       endif
 580 # endif /* ECOS */
 581     }
 582
 583     void GC_reset_fault_handler()
 584     {
 585 # ifndef ECOS
 586 #       if defined(SUNOS5SIGS) || defined(IRIX5) || defined(OSF1)
 587           (void) sigaction(SIGSEGV, &old_segv_act, 0);
 588 #         if defined(IRIX5) && defined(_sigargs) /* Irix 5.x, not 6.x */ \
 589              || defined(HPUX)
 590               (void) sigaction(SIGBUS, &old_bus_act, 0);
 591 #         endif
 592 #       else
 593           (void) signal(SIGSEGV, old_segv_handler);
 594 #         ifdef SIGBUS
 595             (void) signal(SIGBUS, old_bus_handler);
 596 #         endif
 597 #       endif
 598 # endif /* ECOS */
 599     }
 600
 601     /* Return the first nonaddressible location > p (up) or     */
 602     /* the smallest location q s.t. [q,p] is addressible (!up). */
 603     ptr_t GC_find_limit(p, up)
 604     ptr_t p;
 605     GC_bool up;
 606     {
 607 # ifndef ECOS
 608         static VOLATILE ptr_t result;
 609                 /* Needs to be static, since otherwise it may not be    */
 610                 /* preserved across the longjmp.  Can safely be         */
 611                 /* static since it's only called once, with the         */
 612                 /* allocation lock held.                                */
 613
 614
 615         GC_setup_temporary_fault_handler();
 616         if (setjmp(GC_jmp_buf) == 0) {
 617             result = (ptr_t)(((word)(p))
 618                               & ~(MIN_PAGE_SIZE-1));
 619             for (;;) {
 620                 if (up) {
 621                     result += MIN_PAGE_SIZE;
 622                 } else {
 623                     result -= MIN_PAGE_SIZE;
 624                 }
 625                 GC_noop1((word)(*result));
 626             }
 627         }
 628         GC_reset_fault_handler();
 629         if (!up) {
 630             result += MIN_PAGE_SIZE;
 631         }
 632         return(result);
 633 # else /* ECOS */
 634         abort();
 635 # endif /* ECOS */
 636     }
 637 # endif
 638
 639 # ifndef ECOS
 640
 641 #ifdef LINUX_STACKBOTTOM
 642
 643 # define STAT_SKIP 27   /* Number of fields preceding startstack        */
 644                         /* field in /proc/<pid>/stat                    */
 645
 646   ptr_t GC_linux_stack_base(void)
 647   {
 648     char buf[50];
 649     FILE *f;
 650     char c;
 651     word result = 0;
 652     int i;
 653
 654     sprintf(buf, "/proc/%d/stat", getpid());
 655     f = fopen(buf, "r");
 656     if (NULL == f) ABORT("Couldn't open /proc/<pid>/stat");
 657     c = getc(f);
 658     /* Skip the required number of fields.  This number is hopefully    */
 659     /* constant across all Linux implementations.                       */
 660       for (i = 0; i < STAT_SKIP; ++i) {
 661         while (isspace(c)) c = getc(f);
 662         while (!isspace(c)) c = getc(f);
 663       }
 664     while (isspace(c)) c = getc(f);
 665     while (isdigit(c)) {
 666       result *= 10;
 667       result += c - '0';
 668       c = getc(f);
 669     }
 670     if (result < 0x10000000) ABORT("Absurd stack bottom value");
 671     return (ptr_t)result;
 672   }
 673
 674 #endif /* LINUX_STACKBOTTOM */
 675
 676 ptr_t GC_get_stack_base()
 677 {
 678     word dummy;
 679     ptr_t result;
 680
 681 #   define STACKBOTTOM_ALIGNMENT_M1 ((word)STACK_GRAN - 1)
 682
 683 #  if defined(STACKBASE)
 684     extern ptr_t STACKBASE;
 685     return(STACKBASE);
 686 #   else
 687 #   ifdef STACKBOTTOM
 688         return(STACKBOTTOM);
 689 #   else
 690 #       ifdef HEURISTIC1
 691 #          ifdef STACK_GROWS_DOWN
 692              result = (ptr_t)((((word)(&dummy))
 693                                + STACKBOTTOM_ALIGNMENT_M1)
 694                               & ~STACKBOTTOM_ALIGNMENT_M1);
 695 #          else
 696              result = (ptr_t)(((word)(&dummy))
 697                               & ~STACKBOTTOM_ALIGNMENT_M1);
 698 #          endif
 699 #       endif /* HEURISTIC1 */
 700 #       ifdef LINUX_STACKBOTTOM
 701            result = GC_linux_stack_base();
 702 #       endif
 703 #       ifdef HEURISTIC2
 704 #           ifdef STACK_GROWS_DOWN
 705                 result = GC_find_limit((ptr_t)(&dummy), TRUE);
 706 #               ifdef HEURISTIC2_LIMIT
 707                     if (result > HEURISTIC2_LIMIT
 708                         && (ptr_t)(&dummy) < HEURISTIC2_LIMIT) {
 709                             result = HEURISTIC2_LIMIT;
 710                     }
 711 #               endif
 712 #           else
 713                 result = GC_find_limit((ptr_t)(&dummy), FALSE);
 714 #               ifdef HEURISTIC2_LIMIT
 715                     if (result < HEURISTIC2_LIMIT
 716                         && (ptr_t)(&dummy) > HEURISTIC2_LIMIT) {
 717                             result = HEURISTIC2_LIMIT;
 718                     }
 719 #               endif
 720 #           endif
 721
 722 #       endif /* HEURISTIC2 */
 723 #       ifdef STACK_GROWS_DOWN
 724             if (result == 0) result = (ptr_t)(signed_word)(-sizeof(ptr_t));
 725 #       endif
 726         return(result);
 727 #   endif /* STACKBOTTOM */
 728 #   endif /* STACKBASE */
 729 }
 730 # endif /* ECOS */
 731
 732 # endif /* ! AMIGA */
 733 # endif /* ! OS2 */
 734 # endif /* ! MSWIN32 */
 735
 736 /*
 737  * Register static data segment(s) as roots.
 738  * If more data segments are added later then they need to be registered
 739  * add that point (as we do with SunOS dynamic loading),
 740  * or GC_mark_roots needs to check for them (as we do with PCR).
 741  * Called with allocator lock held.
 742  */
 743
 744 # ifdef OS2
 745
 746 void GC_register_data_segments()
 747 {
 748     PTIB ptib;
 749     PPIB ppib;
 750     HMODULE module_handle;
 751 #   define PBUFSIZ 512
 752     UCHAR path[PBUFSIZ];
 753     FILE * myexefile;
 754     struct exe_hdr hdrdos;      /* MSDOS header.        */
 755     struct e32_exe hdr386;      /* Real header for my executable */
 756     struct o32_obj seg; /* Currrent segment */
 757     int nsegs;
 758
 759
 760     if (DosGetInfoBlocks(&ptib, &ppib) != NO_ERROR) {
 761         GC_err_printf0("DosGetInfoBlocks failed\n");
 762         ABORT("DosGetInfoBlocks failed\n");
 763     }
 764     module_handle = ppib -> pib_hmte;
 765     if (DosQueryModuleName(module_handle, PBUFSIZ, path) != NO_ERROR) {
 766         GC_err_printf0("DosQueryModuleName failed\n");
 767         ABORT("DosGetInfoBlocks failed\n");
 768     }
 769     myexefile = fopen(path, "rb");
 770     if (myexefile == 0) {
 771         GC_err_puts("Couldn't open executable ");
 772         GC_err_puts(path); GC_err_puts("\n");
 773         ABORT("Failed to open executable\n");
 774     }
 775     if (fread((char *)(&hdrdos), 1, sizeof hdrdos, myexefile) < sizeof hdrdos) {
 776         GC_err_puts("Couldn't read MSDOS header from ");
 777         GC_err_puts(path); GC_err_puts("\n");
 778         ABORT("Couldn't read MSDOS header");
 779     }
 780     if (E_MAGIC(hdrdos) != EMAGIC) {
 781         GC_err_puts("Executable has wrong DOS magic number: ");
 782         GC_err_puts(path); GC_err_puts("\n");
 783         ABORT("Bad DOS magic number");
 784     }
 785     if (fseek(myexefile, E_LFANEW(hdrdos), SEEK_SET) != 0) {
 786         GC_err_puts("Seek to new header failed in ");
 787         GC_err_puts(path); GC_err_puts("\n");
 788         ABORT("Bad DOS magic number");
 789     }
 790     if (fread((char *)(&hdr386), 1, sizeof hdr386, myexefile) < sizeof hdr386) {
 791         GC_err_puts("Couldn't read MSDOS header from ");
 792         GC_err_puts(path); GC_err_puts("\n");
 793         ABORT("Couldn't read OS/2 header");
 794     }
 795     if (E32_MAGIC1(hdr386) != E32MAGIC1 || E32_MAGIC2(hdr386) != E32MAGIC2) {
 796         GC_err_puts("Executable has wrong OS/2 magic number:");
 797         GC_err_puts(path); GC_err_puts("\n");
 798         ABORT("Bad OS/2 magic number");
 799     }
 800     if ( E32_BORDER(hdr386) != E32LEBO || E32_WORDER(hdr386) != E32LEWO) {
 801         GC_err_puts("Executable %s has wrong byte order: ");
 802         GC_err_puts(path); GC_err_puts("\n");
 803         ABORT("Bad byte order");
 804     }
 805     if ( E32_CPU(hdr386) == E32CPU286) {
 806         GC_err_puts("GC can't handle 80286 executables: ");
 807         GC_err_puts(path); GC_err_puts("\n");
 808         EXIT();
 809     }
 810     if (fseek(myexefile, E_LFANEW(hdrdos) + E32_OBJTAB(hdr386),
 811               SEEK_SET) != 0) {
 812         GC_err_puts("Seek to object table failed: ");
 813         GC_err_puts(path); GC_err_puts("\n");
 814         ABORT("Seek to object table failed");
 815     }
 816     for (nsegs = E32_OBJCNT(hdr386); nsegs > 0; nsegs--) {
 817       int flags;
 818       if (fread((char *)(&seg), 1, sizeof seg, myexefile) < sizeof seg) {
 819         GC_err_puts("Couldn't read obj table entry from ");
 820         GC_err_puts(path); GC_err_puts("\n");
 821         ABORT("Couldn't read obj table entry");
 822       }
 823       flags = O32_FLAGS(seg);
 824       if (!(flags & OBJWRITE)) continue;
 825       if (!(flags & OBJREAD)) continue;
 826       if (flags & OBJINVALID) {
 827           GC_err_printf0("Object with invalid pages?\n");
 828           continue;
 829       }
 830       GC_add_roots_inner(O32_BASE(seg), O32_BASE(seg)+O32_SIZE(seg), FALSE);
 831     }
 832 }
 833
 834 # else
 835
 836 # ifdef MSWIN32
 837   /* Unfortunately, we have to handle win32s very differently from NT,  */
 838   /* Since VirtualQuery has very different semantics.  In particular,   */
 839   /* under win32s a VirtualQuery call on an unmapped page returns an    */
 840   /* invalid result.  Under GC_register_data_segments is a noop and     */
 841   /* all real work is done by GC_register_dynamic_libraries.  Under     */
 842   /* win32s, we cannot find the data segments associated with dll's.    */
 843   /* We rgister the main data segment here.                             */
 844   GC_bool GC_win32s = FALSE;    /* We're running under win32s.  */
 845
 846   GC_bool GC_is_win32s()
 847   {
 848       DWORD v = GetVersion();
 849
 850       /* Check that this is not NT, and Windows major version <= 3      */
 851       return ((v & 0x80000000) && (v & 0xff) <= 3);
 852   }
 853
 854   void GC_init_win32()
 855   {
 856       GC_win32s = GC_is_win32s();
 857   }
 858
 859   /* Return the smallest address a such that VirtualQuery               */
 860   /* returns correct results for all addresses between a and start.     */
 861   /* Assumes VirtualQuery returns correct information for start.        */
 862   ptr_t GC_least_described_address(ptr_t start)
 863   {
 864     MEMORY_BASIC_INFORMATION buf;
 865     SYSTEM_INFO sysinfo;
 866     DWORD result;
 867     LPVOID limit;
 868     ptr_t p;
 869     LPVOID q;
 870
 871     GetSystemInfo(&sysinfo);
 872     limit = sysinfo.lpMinimumApplicationAddress;
 873     p = (ptr_t)((word)start & ~(GC_page_size - 1));
 874     for (;;) {
 875         q = (LPVOID)(p - GC_page_size);
 876         if ((ptr_t)q > (ptr_t)p /* underflow */ || q < limit) break;
 877         result = VirtualQuery(q, &buf, sizeof(buf));
 878         if (result != sizeof(buf) || buf.AllocationBase == 0) break;
 879         p = (ptr_t)(buf.AllocationBase);
 880     }
 881     return(p);
 882   }
 883
 884   /* Is p the start of either the malloc heap, or of one of our */
 885   /* heap sections?                                             */
 886   GC_bool GC_is_heap_base (ptr_t p)
 887   {
 888
 889      register unsigned i;
 890
 891 #    ifndef REDIRECT_MALLOC
 892        static ptr_t malloc_heap_pointer = 0;
 893
 894        if (0 == malloc_heap_pointer) {
 895          MEMORY_BASIC_INFORMATION buf;
 896          register DWORD result = VirtualQuery(malloc(1), &buf, sizeof(buf));
 897
 898          if (result != sizeof(buf)) {
 899              ABORT("Weird VirtualQuery result");
 900          }
 901          malloc_heap_pointer = (ptr_t)(buf.AllocationBase);
 902        }
 903        if (p == malloc_heap_pointer) return(TRUE);
 904 #    endif
 905      for (i = 0; i < GC_n_heap_bases; i++) {
 906          if (GC_heap_bases[i] == p) return(TRUE);
 907      }
 908      return(FALSE);
 909   }
 910
 911   void GC_register_root_section(ptr_t static_root)
 912   {
 913       MEMORY_BASIC_INFORMATION buf;
 914       SYSTEM_INFO sysinfo;
 915       DWORD result;
 916       DWORD protect;
 917       LPVOID p;
 918       char * base;
 919       char * limit, * new_limit;
 920
 921       if (!GC_win32s) return;
 922       p = base = limit = GC_least_described_address(static_root);
 923       GetSystemInfo(&sysinfo);
 924       while (p < sysinfo.lpMaximumApplicationAddress) {
 925         result = VirtualQuery(p, &buf, sizeof(buf));
 926         if (result != sizeof(buf) || buf.AllocationBase == 0
 927             || GC_is_heap_base(buf.AllocationBase)) break;
 928         new_limit = (char *)p + buf.RegionSize;
 929         protect = buf.Protect;
 930         if (buf.State == MEM_COMMIT
 931             && is_writable(protect)) {
 932             if ((char *)p == limit) {
 933                 limit = new_limit;
 934             } else {
 935                 if (base != limit) GC_add_roots_inner(base, limit, FALSE);
 936                 base = p;
 937                 limit = new_limit;
 938             }
 939         }
 940         if (p > (LPVOID)new_limit /* overflow */) break;
 941         p = (LPVOID)new_limit;
 942       }
 943       if (base != limit) GC_add_roots_inner(base, limit, FALSE);
 944   }
 945
 946   void GC_register_data_segments()
 947   {
 948       static char dummy;
 949
 950       GC_register_root_section((ptr_t)(&dummy));
 951   }
 952 # else
 953 # ifdef AMIGA
 954
 955    void GC_register_data_segments()
 956    {
 957      struct Process     *proc;
 958      struct CommandLineInterface *cli;
 959      BPTR myseglist;
 960      ULONG *data;
 961
 962      int        num;
 963
 964
 965 #    ifdef __GNUC__
 966         ULONG dataSegSize;
 967         GC_bool found_segment = FALSE;
 968         extern char __data_size[];
 969
 970         dataSegSize=__data_size+8;
 971         /* Can`t find the Location of __data_size, because
 972            it`s possible that is it, inside the segment. */
 973
 974 #     endif
 975
 976         proc= (struct Process*)SysBase->ThisTask;
 977
 978         /* Reference: Amiga Guru Book Pages: 538ff,565,573
 979                      and XOper.asm */
 980         if (proc->pr_Task.tc_Node.ln_Type==NT_PROCESS) {
 981           if (proc->pr_CLI == NULL) {
 982             myseglist = proc->pr_SegList;
 983           } else {
 984             /* ProcLoaded       'Loaded as a command: '*/
 985             cli = BADDR(proc->pr_CLI);
 986             myseglist = cli->cli_Module;
 987           }
 988         } else {
 989           ABORT("Not a Process.");
 990         }
 991
 992         if (myseglist == NULL) {
 993             ABORT("Arrrgh.. can't find segments, aborting");
 994         }
 995
 996         /* xoper hunks Shell Process */
 997
 998         num=0;
 999         for (data = (ULONG *)BADDR(myseglist); data != NULL;
1000              data = (ULONG *)BADDR(data[0])) {
1001           if (((ULONG) GC_register_data_segments < (ULONG) &data[1]) ||
1002               ((ULONG) GC_register_data_segments > (ULONG) &data[1] + data[-1])) {
1003 #             ifdef __GNUC__
1004                 if (dataSegSize == data[-1]) {
1005                   found_segment = TRUE;
1006                 }
1007 #             endif
1008               GC_add_roots_inner((char *)&data[1],
1009                                  ((char *)&data[1]) + data[-1], FALSE);
1010           }
1011           ++num;
1012         } /* for */
1013 #       ifdef __GNUC__
1014            if (!found_segment) {
1015              ABORT("Can`t find correct Segments.\nSolution: Use an newer version of ixemul.library");
1016            }
1017 #       endif
1018   }
1019
1020 #if 0 /* old version */
1021   void GC_register_data_segments()
1022   {
1023     extern struct WBStartup *_WBenchMsg;
1024     struct Process      *proc;
1025     struct CommandLineInterface *cli;
1026     BPTR myseglist;
1027     ULONG *data;
1028
1029     if ( _WBenchMsg != 0 ) {
1030         if ((myseglist = _WBenchMsg->sm_Segment) == 0) {
1031             GC_err_puts("No seglist from workbench\n");
1032             return;
1033         }
1034     } else {
1035         if ((proc = (struct Process *)FindTask(0)) == 0) {
1036             GC_err_puts("Cannot find process structure\n");
1037             return;
1038         }
1039         if ((cli = BADDR(proc->pr_CLI)) == 0) {
1040             GC_err_puts("No CLI\n");
1041             return;
1042         }
1043         if ((myseglist = cli->cli_Module) == 0) {
1044             GC_err_puts("No seglist from CLI\n");
1045             return;
1046         }
1047     }
1048
1049     for (data = (ULONG *)BADDR(myseglist); data != 0;
1050          data = (ULONG *)BADDR(data[0])) {
1051 #        ifdef AMIGA_SKIP_SEG
1052            if (((ULONG) GC_register_data_segments < (ULONG) &data[1]) ||
1053            ((ULONG) GC_register_data_segments > (ULONG) &data[1] + data[-1])) {
1054 #        else
1055            {
1056 #        endif /* AMIGA_SKIP_SEG */
1057           GC_add_roots_inner((char *)&data[1],
1058                              ((char *)&data[1]) + data[-1], FALSE);
1059          }
1060     }
1061   }
1062 #endif /* old version */
1063
1064
1065 # else
1066
1067 # if (defined(SVR4) || defined(AUX) || defined(DGUX)) && !defined(PCR)
1068 char * GC_SysVGetDataStart(max_page_size, etext_addr)
1069 int max_page_size;
1070 int * etext_addr;
1071 {
1072     word text_end = ((word)(etext_addr) + sizeof(word) - 1)
1073                     & ~(sizeof(word) - 1);
1074         /* etext rounded to word boundary       */
1075     word next_page = ((text_end + (word)max_page_size - 1)
1076                       & ~((word)max_page_size - 1));
1077     word page_offset = (text_end & ((word)max_page_size - 1));
1078     VOLATILE char * result = (char *)(next_page + page_offset);
1079     /* Note that this isnt equivalent to just adding            */
1080     /* max_page_size to &etext if &etext is at a page boundary  */
1081
1082     GC_setup_temporary_fault_handler();
1083     if (setjmp(GC_jmp_buf) == 0) {
1084         /* Try writing to the address.  */
1085         *result = *result;
1086         GC_reset_fault_handler();
1087     } else {
1088         GC_reset_fault_handler();
1089         /* We got here via a longjmp.  The address is not readable.     */
1090         /* This is known to happen under Solaris 2.4 + gcc, which place */
1091         /* string constants in the text segment, but after etext.       */
1092         /* Use plan B.  Note that we now know there is a gap between    */
1093         /* text and data segments, so plan A bought us something.       */
1094         result = (char *)GC_find_limit((ptr_t)(DATAEND) - MIN_PAGE_SIZE, FALSE);
1095     }
1096     return((char *)result);
1097 }
1098 # endif
1099
1100
1101 void GC_register_data_segments()
1102 {
1103 #   if !defined(PCR) && !defined(SRC_M3) && !defined(NEXT) && !defined(MACOS) \
1104        && !defined(MACOSX)
1105 #     if defined(REDIRECT_MALLOC) && defined(SOLARIS_THREADS)
1106         /* As of Solaris 2.3, the Solaris threads implementation        */
1107         /* allocates the data structure for the initial thread with     */
1108         /* sbrk at process startup.  It needs to be scanned, so that    */
1109         /* we don't lose some malloc allocated data structures          */
1110         /* hanging from it.  We're on thin ice here ...                 */
1111         extern caddr_t sbrk();
1112
1113         GC_add_roots_inner(DATASTART, (char *)sbrk(0), FALSE);
1114 #     else
1115         GC_add_roots_inner(DATASTART, (char *)(DATAEND), FALSE);
1116 #     endif
1117 #   endif
1118 #   if !defined(PCR) && (defined(NEXT) || defined(MACOSX))
1119       GC_add_roots_inner(DATASTART, (char *) get_end(), FALSE);
1120 #   endif
1121 #   if defined(MACOS)
1122     {
1123 #   if defined(THINK_C)
1124         extern void* GC_MacGetDataStart(void);
1125         /* globals begin above stack and end at a5. */
1126         GC_add_roots_inner((ptr_t)GC_MacGetDataStart(),
1127                            (ptr_t)LMGetCurrentA5(), FALSE);
1128 #   else
1129 #     if defined(__MWERKS__)
1130 #       if !__POWERPC__
1131           extern void* GC_MacGetDataStart(void);
1132           /* MATTHEW: Function to handle Far Globals (CW Pro 3) */
1133 #         if __option(far_data)
1134           extern void* GC_MacGetDataEnd(void);
1135 #         endif
1136           /* globals begin above stack and end at a5. */
1137           GC_add_roots_inner((ptr_t)GC_MacGetDataStart(),
1138                              (ptr_t)LMGetCurrentA5(), FALSE);
1139           /* MATTHEW: Handle Far Globals */
1140 #         if __option(far_data)
1141       /* Far globals follow he QD globals: */
1142           GC_add_roots_inner((ptr_t)LMGetCurrentA5(),
1143                              (ptr_t)GC_MacGetDataEnd(), FALSE);
1144 #         endif
1145 #       else
1146           extern char __data_start__[], __data_end__[];
1147           GC_add_roots_inner((ptr_t)&__data_start__,
1148                              (ptr_t)&__data_end__, FALSE);
1149 #       endif /* __POWERPC__ */
1150 #     endif /* __MWERKS__ */
1151 #   endif /* !THINK_C */
1152     }
1153 #   endif /* MACOS */
1154
1155     /* Dynamic libraries are added at every collection, since they may  */
1156     /* change.                                                          */
1157 }
1158
1159 # endif  /* ! AMIGA */
1160 # endif  /* ! MSWIN32 */
1161 # endif  /* ! OS2 */
1162
1163 /*
1164  * Auxiliary routines for obtaining memory from OS.
1165  */
1166
1167 # if !defined(OS2) && !defined(PCR) && !defined(AMIGA) \
1168         && !defined(MSWIN32) && !defined(MACOS) && !defined(DOS4GW)
1169
1170 # ifdef SUNOS4
1171     extern caddr_t sbrk();
1172 # endif
1173 # ifdef __STDC__
1174 #   define SBRK_ARG_T ptrdiff_t
1175 # else
1176 #   define SBRK_ARG_T int
1177 # endif
1178
1179 # ifdef RS6000
1180 /* The compiler seems to generate speculative reads one past the end of */
1181 /* an allocated object.  Hence we need to make sure that the page       */
1182 /* following the last heap page is also mapped.                         */
1183 ptr_t GC_unix_get_mem(bytes)
1184 word bytes;
1185 {
1186     caddr_t cur_brk = (caddr_t)sbrk(0);
1187     caddr_t result;
1188     SBRK_ARG_T lsbs = (word)cur_brk & (GC_page_size-1);
1189     static caddr_t my_brk_val = 0;
1190
1191     if ((SBRK_ARG_T)bytes < 0) return(0); /* too big */
1192     if (lsbs != 0) {
1193         if((caddr_t)(sbrk(GC_page_size - lsbs)) == (caddr_t)(-1)) return(0);
1194     }
1195     if (cur_brk == my_brk_val) {
1196         /* Use the extra block we allocated last time. */
1197         result = (ptr_t)sbrk((SBRK_ARG_T)bytes);
1198         if (result == (caddr_t)(-1)) return(0);
1199         result -= GC_page_size;
1200     } else {
1201         result = (ptr_t)sbrk(GC_page_size + (SBRK_ARG_T)bytes);
1202         if (result == (caddr_t)(-1)) return(0);
1203     }
1204     my_brk_val = result + bytes + GC_page_size; /* Always page aligned */
1205     return((ptr_t)result);
1206 }
1207
1208 #else  /* Not RS6000 */
1209
1210 #if defined(USE_MMAP)
1211 /* Tested only under IRIX5 and Solaris 2 */
1212
1213 #ifdef USE_MMAP_FIXED
1214 #   define GC_MMAP_FLAGS MAP_FIXED | MAP_PRIVATE
1215         /* Seems to yield better performance on Solaris 2, but can      */
1216         /* be unreliable if something is already mapped at the address. */
1217 #else
1218 #   define GC_MMAP_FLAGS MAP_PRIVATE
1219 #endif
1220
1221 ptr_t GC_unix_get_mem(bytes)
1222 word bytes;
1223 {
1224     static GC_bool initialized = FALSE;
1225     static int fd;
1226     void *result;
1227     static ptr_t last_addr = HEAP_START;
1228
1229     if (!initialized) {
1230         fd = open("/dev/zero", O_RDONLY);
1231         initialized = TRUE;
1232     }
1233     if (bytes & (GC_page_size -1)) ABORT("Bad GET_MEM arg");
1234     result = mmap(last_addr, bytes, PROT_READ | PROT_WRITE | OPT_PROT_EXEC,
1235                   GC_MMAP_FLAGS, fd, 0/* offset */);
1236     if (result == MAP_FAILED) return(0);
1237     last_addr = (ptr_t)result + bytes + GC_page_size - 1;
1238     last_addr = (ptr_t)((word)last_addr & ~(GC_page_size - 1));
1239     return((ptr_t)result);
1240 }
1241
1242 #else /* Not RS6000, not USE_MMAP */
1243 ptr_t GC_unix_get_mem(bytes)
1244 word bytes;
1245 {
1246   ptr_t result;
1247 # ifdef IRIX5
1248     /* Bare sbrk isn't thread safe.  Play by malloc rules.      */
1249     /* The equivalent may be needed on other systems as well.   */
1250     __LOCK_MALLOC();
1251 # endif
1252   {
1253     ptr_t cur_brk = (ptr_t)sbrk(0);
1254     SBRK_ARG_T lsbs = (word)cur_brk & (GC_page_size-1);
1255
1256     if ((SBRK_ARG_T)bytes < 0) return(0); /* too big */
1257     if (lsbs != 0) {
1258         if((ptr_t)sbrk(GC_page_size - lsbs) == (ptr_t)(-1)) return(0);
1259     }
1260     result = (ptr_t)sbrk((SBRK_ARG_T)bytes);
1261     if (result == (ptr_t)(-1)) result = 0;
1262   }
1263 # ifdef IRIX5
1264     __UNLOCK_MALLOC();
1265 # endif
1266   return(result);
1267 }
1268
1269 #endif /* Not USE_MMAP */
1270 #endif /* Not RS6000 */
1271
1272 # endif /* UN*X */
1273
1274 # ifdef OS2
1275
1276 void * os2_alloc(size_t bytes)
1277 {
1278     void * result;
1279
1280     if (DosAllocMem(&result, bytes, PAG_EXECUTE | PAG_READ |
1281                                     PAG_WRITE | PAG_COMMIT)
1282                     != NO_ERROR) {
1283         return(0);
1284     }
1285     if (result == 0) return(os2_alloc(bytes));
1286     return(result);
1287 }
1288
1289 # endif /* OS2 */
1290
1291
1292 # ifdef MSWIN32
1293 word GC_n_heap_bases = 0;
1294
1295 ptr_t GC_win32_get_mem(bytes)
1296 word bytes;
1297 {
1298     ptr_t result;
1299
1300     if (GC_win32s) {
1301         /* VirtualAlloc doesn't like PAGE_EXECUTE_READWRITE.    */
1302         /* There are also unconfirmed rumors of other           */
1303         /* problems, so we dodge the issue.                     */
1304         result = (ptr_t) GlobalAlloc(0, bytes + HBLKSIZE);
1305         result = (ptr_t)(((word)result + HBLKSIZE) & ~(HBLKSIZE-1));
1306     } else {
1307         result = (ptr_t) VirtualAlloc(NULL, bytes,
1308                                       MEM_COMMIT | MEM_RESERVE,
1309                                       PAGE_EXECUTE_READWRITE);
1310     }
1311     if (HBLKDISPL(result) != 0) ABORT("Bad VirtualAlloc result");
1312         /* If I read the documentation correctly, this can      */
1313         /* only happen if HBLKSIZE > 64k or not a power of 2.   */
1314     if (GC_n_heap_bases >= MAX_HEAP_SECTS) ABORT("Too many heap sections");
1315     GC_heap_bases[GC_n_heap_bases++] = result;
1316     return(result);
1317 }
1318
1319 void GC_win32_free_heap ()
1320 {
1321     if (GC_win32s) {
1322         while (GC_n_heap_bases > 0) {
1323             GlobalFree (GC_heap_bases[--GC_n_heap_bases]);
1324             GC_heap_bases[GC_n_heap_bases] = 0;
1325         }
1326     }
1327 }
1328
1329
1330 # endif
1331
1332 #ifdef USE_MUNMAP
1333
1334 /* For now, this only works on some Unix-like systems.  If you  */
1335 /* have something else, don't define USE_MUNMAP.                */
1336 /* We assume ANSI C to support this feature.                    */
1337 #include <unistd.h>
1338 #include <sys/mman.h>
1339 #include <sys/stat.h>
1340 #include <sys/types.h>
1341 #include <fcntl.h>
1342
1343 /* Compute a page aligned starting address for the unmap        */
1344 /* operation on a block of size bytes starting at start.        */
1345 /* Return 0 if the block is too small to make this feasible.    */
1346 ptr_t GC_unmap_start(ptr_t start, word bytes)
1347 {
1348     ptr_t result = start;
1349     /* Round start to next page boundary.       */
1350         result += GC_page_size - 1;
1351         result = (ptr_t)((word)result & ~(GC_page_size - 1));
1352     if (result + GC_page_size > start + bytes) return 0;
1353     return result;
1354 }
1355
1356 /* Compute end address for an unmap operation on the indicated  */
1357 /* block.                                                       */
1358 ptr_t GC_unmap_end(ptr_t start, word bytes)
1359 {
1360     ptr_t end_addr = start + bytes;
1361     end_addr = (ptr_t)((word)end_addr & ~(GC_page_size - 1));
1362     return end_addr;
1363 }
1364
1365 /* We assume that GC_remap is called on exactly the same range  */
1366 /* as a previous call to GC_unmap.  It is safe to consistently  */
1367 /* round the endpoints in both places.                          */
1368 void GC_unmap(ptr_t start, word bytes)
1369 {
1370     ptr_t start_addr = GC_unmap_start(start, bytes);
1371     ptr_t end_addr = GC_unmap_end(start, bytes);
1372     word len = end_addr - start_addr;
1373     if (0 == start_addr) return;
1374     if (munmap(start_addr, len) != 0) ABORT("munmap failed");
1375     GC_unmapped_bytes += len;
1376 }
1377
1378
1379 void GC_remap(ptr_t start, word bytes)
1380 {
1381     static int zero_descr = -1;
1382     ptr_t start_addr = GC_unmap_start(start, bytes);
1383     ptr_t end_addr = GC_unmap_end(start, bytes);
1384     word len = end_addr - start_addr;
1385     ptr_t result;
1386
1387     if (-1 == zero_descr) zero_descr = open("/dev/zero", O_RDWR);
1388     if (0 == start_addr) return;
1389     result = mmap(start_addr, len, PROT_READ | PROT_WRITE | OPT_PROT_EXEC,
1390                   MAP_FIXED | MAP_PRIVATE, zero_descr, 0);
1391     if (result != start_addr) {
1392         ABORT("mmap remapping failed");
1393     }
1394     GC_unmapped_bytes -= len;
1395 }
1396
1397 /* Two adjacent blocks have already been unmapped and are about to      */
1398 /* be merged.  Unmap the whole block.  This typically requires          */
1399 /* that we unmap a small section in the middle that was not previously  */
1400 /* unmapped due to alignment constraints.                               */
1401 void GC_unmap_gap(ptr_t start1, word bytes1, ptr_t start2, word bytes2)
1402 {
1403     ptr_t start1_addr = GC_unmap_start(start1, bytes1);
1404     ptr_t end1_addr = GC_unmap_end(start1, bytes1);
1405     ptr_t start2_addr = GC_unmap_start(start2, bytes2);
1406     ptr_t end2_addr = GC_unmap_end(start2, bytes2);
1407     ptr_t start_addr = end1_addr;
1408     ptr_t end_addr = start2_addr;
1409     word len;
1410     GC_ASSERT(start1 + bytes1 == start2);
1411     if (0 == start1_addr) start_addr = GC_unmap_start(start1, bytes1 + bytes2);
1412     if (0 == start2_addr) end_addr = GC_unmap_end(start1, bytes1 + bytes2);
1413     if (0 == start_addr) return;
1414     len = end_addr - start_addr;
1415     if (len != 0 && munmap(start_addr, len) != 0) ABORT("munmap failed");
1416     GC_unmapped_bytes += len;
1417 }
1418
1419 #endif /* USE_MUNMAP */
1420
1421 /* Routine for pushing any additional roots.  In THREADS        */
1422 /* environment, this is also responsible for marking from       */
1423 /* thread stacks.  In the SRC_M3 case, it also handles          */
1424 /* global variables.                                            */
1425 #ifndef THREADS
1426 void (*GC_push_other_roots)() = 0;
1427 #else /* THREADS */
1428
1429 # ifdef PCR
1430 PCR_ERes GC_push_thread_stack(PCR_Th_T *t, PCR_Any dummy)
1431 {
1432     struct PCR_ThCtl_TInfoRep info;
1433     PCR_ERes result;
1434
1435     info.ti_stkLow = info.ti_stkHi = 0;
1436     result = PCR_ThCtl_GetInfo(t, &info);
1437     GC_push_all_stack((ptr_t)(info.ti_stkLow), (ptr_t)(info.ti_stkHi));
1438     return(result);
1439 }
1440
1441 /* Push the contents of an old object. We treat this as stack   */
1442 /* data only becasue that makes it robust against mark stack    */
1443 /* overflow.                                                    */
1444 PCR_ERes GC_push_old_obj(void *p, size_t size, PCR_Any data)
1445 {
1446     GC_push_all_stack((ptr_t)p, (ptr_t)p + size);
1447     return(PCR_ERes_okay);
1448 }
1449
1450
1451 void GC_default_push_other_roots()
1452 {
1453     /* Traverse data allocated by previous memory managers.             */
1454         {
1455           extern struct PCR_MM_ProcsRep * GC_old_allocator;
1456
1457           if ((*(GC_old_allocator->mmp_enumerate))(PCR_Bool_false,
1458                                                    GC_push_old_obj, 0)
1459               != PCR_ERes_okay) {
1460               ABORT("Old object enumeration failed");
1461           }
1462         }
1463     /* Traverse all thread stacks. */
1464         if (PCR_ERes_IsErr(
1465                 PCR_ThCtl_ApplyToAllOtherThreads(GC_push_thread_stack,0))
1466               || PCR_ERes_IsErr(GC_push_thread_stack(PCR_Th_CurrThread(), 0))) {
1467               ABORT("Thread stack marking failed\n");
1468         }
1469 }
1470
1471 # endif /* PCR */
1472
1473 # ifdef SRC_M3
1474
1475 # ifdef ALL_INTERIOR_POINTERS
1476     --> misconfigured
1477 # endif
1478
1479
1480 extern void ThreadF__ProcessStacks();
1481
1482 void GC_push_thread_stack(start, stop)
1483 word start, stop;
1484 {
1485    GC_push_all_stack((ptr_t)start, (ptr_t)stop + sizeof(word));
1486 }
1487
1488 /* Push routine with M3 specific calling convention. */
1489 GC_m3_push_root(dummy1, p, dummy2, dummy3)
1490 word *p;
1491 ptr_t dummy1, dummy2;
1492 int dummy3;
1493 {
1494     word q = *p;
1495
1496     if ((ptr_t)(q) >= GC_least_plausible_heap_addr
1497          && (ptr_t)(q) < GC_greatest_plausible_heap_addr) {
1498          GC_push_one_checked(q,FALSE);
1499     }
1500 }
1501
1502 /* M3 set equivalent to RTHeap.TracedRefTypes */
1503 typedef struct { int elts[1]; }  RefTypeSet;
1504 RefTypeSet GC_TracedRefTypes = {{0x1}};
1505
1506 /* From finalize.c */
1507 extern void GC_push_finalizer_structures();
1508
1509 /* From stubborn.c: */
1510 # ifdef STUBBORN_ALLOC
1511     extern GC_PTR * GC_changing_list_start;
1512 # endif
1513
1514
1515 void GC_default_push_other_roots()
1516 {
1517     /* Use the M3 provided routine for finding static roots.    */
1518     /* This is a bit dubious, since it presumes no C roots.     */
1519     /* We handle the collector roots explicitly.                */
1520        {
1521 #        ifdef STUBBORN_ALLOC
1522            GC_push_one(GC_changing_list_start);
1523 #        endif
1524          GC_push_finalizer_structures();
1525          RTMain__GlobalMapProc(GC_m3_push_root, 0, GC_TracedRefTypes);
1526        }
1527         if (GC_words_allocd > 0) {
1528             ThreadF__ProcessStacks(GC_push_thread_stack);
1529         }
1530         /* Otherwise this isn't absolutely necessary, and we have       */
1531         /* startup ordering problems.                                   */
1532 }
1533
1534 # endif /* SRC_M3 */
1535
1536 # if defined(SOLARIS_THREADS) || defined(WIN32_THREADS) \
1537      || defined(IRIX_THREADS) || defined(LINUX_THREADS) \
1538      || defined(IRIX_JDK_THREADS) || defined(HPUX_THREADS)
1539
1540 extern void GC_push_all_stacks();
1541
1542 void GC_default_push_other_roots()
1543 {
1544     GC_push_all_stacks();
1545 }
1546
1547 # endif /* SOLARIS_THREADS || ... */
1548
1549 void (*GC_push_other_roots)() = GC_default_push_other_roots;
1550
1551 #endif
1552
1553 /*
1554  * Routines for accessing dirty  bits on virtual pages.
1555  * We plan to eventaually implement four strategies for doing so:
1556  * DEFAULT_VDB: A simple dummy implementation that treats every page
1557  *              as possibly dirty.  This makes incremental collection
1558  *              useless, but the implementation is still correct.
1559  * PCR_VDB:     Use PPCRs virtual dirty bit facility.
1560  * PROC_VDB:    Use the /proc facility for reading dirty bits.  Only
1561  *              works under some SVR4 variants.  Even then, it may be
1562  *              too slow to be entirely satisfactory.  Requires reading
1563  *              dirty bits for entire address space.  Implementations tend
1564  *              to assume that the client is a (slow) debugger.
1565  * MPROTECT_VDB:Protect pages and then catch the faults to keep track of
1566  *              dirtied pages.  The implementation (and implementability)
1567  *              is highly system dependent.  This usually fails when system
1568  *              calls write to a protected page.  We prevent the read system
1569  *              call from doing so.  It is the clients responsibility to
1570  *              make sure that other system calls are similarly protected
1571  *              or write only to the stack.
1572  */
1573
1574 GC_bool GC_dirty_maintained = FALSE;
1575
1576 # ifdef DEFAULT_VDB
1577
1578 /* All of the following assume the allocation lock is held, and */
1579 /* signals are disabled.                                        */
1580
1581 /* The client asserts that unallocated pages in the heap are never      */
1582 /* written.                                                             */
1583
1584 /* Initialize virtual dirty bit implementation.                 */
1585 void GC_dirty_init()
1586 {
1587     GC_dirty_maintained = TRUE;
1588 }
1589
1590 /* Retrieve system dirty bits for heap to a local buffer.       */
1591 /* Restore the systems notion of which pages are dirty.         */
1592 void GC_read_dirty()
1593 {}
1594
1595 /* Is the HBLKSIZE sized page at h marked dirty in the local buffer?    */
1596 /* If the actual page size is different, this returns TRUE if any       */
1597 /* of the pages overlapping h are dirty.  This routine may err on the   */
1598 /* side of labelling pages as dirty (and this implementation does).     */
1599 /*ARGSUSED*/
1600 GC_bool GC_page_was_dirty(h)
1601 struct hblk *h;
1602 {
1603     return(TRUE);
1604 }
1605
1606 /*
1607  * The following two routines are typically less crucial.  They matter
1608  * most with large dynamic libraries, or if we can't accurately identify
1609  * stacks, e.g. under Solaris 2.X.  Otherwise the following default
1610  * versions are adequate.
1611  */
1612
1613 /* Could any valid GC heap pointer ever have been written to this page? */
1614 /*ARGSUSED*/
1615 GC_bool GC_page_was_ever_dirty(h)
1616 struct hblk *h;
1617 {
1618     return(TRUE);
1619 }
1620
1621 /* Reset the n pages starting at h to "was never dirty" status. */
1622 void GC_is_fresh(h, n)
1623 struct hblk *h;
1624 word n;
1625 {
1626 }
1627
1628 /* A call hints that h is about to be written.  */
1629 /* May speed up some dirty bit implementations. */
1630 /*ARGSUSED*/
1631 void GC_write_hint(h)
1632 struct hblk *h;
1633 {
1634 }
1635
1636 # endif /* DEFAULT_VDB */
1637
1638
1639 # ifdef MPROTECT_VDB
1640
1641 /*
1642  * See DEFAULT_VDB for interface descriptions.
1643  */
1644
1645 /*
1646  * This implementation maintains dirty bits itself by catching write
1647  * faults and keeping track of them.  We assume nobody else catches
1648  * SIGBUS or SIGSEGV.  We assume no write faults occur in system calls
1649  * except as a result of a read system call.  This means clients must
1650  * either ensure that system calls do not touch the heap, or must
1651  * provide their own wrappers analogous to the one for read.
1652  * We assume the page size is a multiple of HBLKSIZE.
1653  * This implementation is currently SunOS 4.X and IRIX 5.X specific, though we
1654  * tried to use portable code where easily possible.  It is known
1655  * not to work under a number of other systems.
1656  */
1657
1658 # ifndef MSWIN32
1659
1660 #   include <sys/mman.h>
1661 #   include <signal.h>
1662 #   include <sys/syscall.h>
1663
1664 #   define PROTECT(addr, len) \
1665           if (mprotect((caddr_t)(addr), (size_t)(len), \
1666                        PROT_READ | OPT_PROT_EXEC) < 0) { \
1667             ABORT("mprotect failed"); \
1668           }
1669 #   define UNPROTECT(addr, len) \
1670           if (mprotect((caddr_t)(addr), (size_t)(len), \
1671                        PROT_WRITE | PROT_READ | OPT_PROT_EXEC ) < 0) { \
1672             ABORT("un-mprotect failed"); \
1673           }
1674
1675 # else
1676
1677 #   include <signal.h>
1678
1679     static DWORD protect_junk;
1680 #   define PROTECT(addr, len) \
1681           if (!VirtualProtect((addr), (len), PAGE_EXECUTE_READ, \
1682                               &protect_junk)) { \
1683             DWORD last_error = GetLastError(); \
1684             GC_printf1("Last error code: %lx\n", last_error); \
1685             ABORT("VirtualProtect failed"); \
1686           }
1687 #   define UNPROTECT(addr, len) \
1688           if (!VirtualProtect((addr), (len), PAGE_EXECUTE_READWRITE, \
1689                               &protect_junk)) { \
1690             ABORT("un-VirtualProtect failed"); \
1691           }
1692
1693 # endif
1694
1695 #if defined(SUNOS4) || defined(FREEBSD)
1696     typedef void (* SIG_PF)();
1697 #endif
1698 #if defined(SUNOS5SIGS) || defined(OSF1) || defined(LINUX)
1699 # ifdef __STDC__
1700     typedef void (* SIG_PF)(int);
1701 # else
1702     typedef void (* SIG_PF)();
1703 # endif
1704 #endif
1705 #if defined(MSWIN32)
1706     typedef LPTOP_LEVEL_EXCEPTION_FILTER SIG_PF;
1707 #   undef SIG_DFL
1708 #   define SIG_DFL (LPTOP_LEVEL_EXCEPTION_FILTER) (-1)
1709 #endif
1710
1711 #if defined(IRIX5) || defined(OSF1)
1712     typedef void (* REAL_SIG_PF)(int, int, struct sigcontext *);
1713 #endif
1714 #if defined(SUNOS5SIGS)
1715 # ifdef HPUX
1716 #   define SIGINFO __siginfo
1717 # else
1718 #   define SIGINFO siginfo
1719 # endif
1720 # ifdef __STDC__
1721     typedef void (* REAL_SIG_PF)(int, struct SIGINFO *, void *);
1722 # else
1723     typedef void (* REAL_SIG_PF)();
1724 # endif
1725 #endif
1726 #if defined(LINUX)
1727 #   include <linux/version.h>
1728 #   if (LINUX_VERSION_CODE >= 0x20100) && !defined(M68K) || defined(ALPHA) || defined(IA64)
1729       typedef struct sigcontext s_c;
1730 #   else
1731       typedef struct sigcontext_struct s_c;
1732 #   endif
1733 #   if defined(ALPHA) || defined(M68K)
1734       typedef void (* REAL_SIG_PF)(int, int, s_c *);
1735 #   else
1736 #     if defined(IA64)
1737         typedef void (* REAL_SIG_PF)(int, siginfo_t *, s_c *);
1738 #     else
1739         typedef void (* REAL_SIG_PF)(int, s_c);
1740 #     endif
1741 #   endif
1742 #   ifdef ALPHA
1743     /* Retrieve fault address from sigcontext structure by decoding     */
1744     /* instruction.                                                     */
1745     char * get_fault_addr(s_c *sc) {
1746         unsigned instr;
1747         word faultaddr;
1748
1749         instr = *((unsigned *)(sc->sc_pc));
1750         faultaddr = sc->sc_regs[(instr >> 16) & 0x1f];
1751         faultaddr += (word) (((int)instr << 16) >> 16);
1752         return (char *)faultaddr;
1753     }
1754 #   endif /* !ALPHA */
1755 # endif
1756
1757 SIG_PF GC_old_bus_handler;
1758 SIG_PF GC_old_segv_handler;     /* Also old MSWIN32 ACCESS_VIOLATION filter */
1759
1760 /*ARGSUSED*/
1761 # if defined (SUNOS4) || defined(FREEBSD)
1762     void GC_write_fault_handler(sig, code, scp, addr)
1763     int sig, code;
1764     struct sigcontext *scp;
1765     char * addr;
1766 #   ifdef SUNOS4
1767 #     define SIG_OK (sig == SIGSEGV || sig == SIGBUS)
1768 #     define CODE_OK (FC_CODE(code) == FC_PROT \
1769                     || (FC_CODE(code) == FC_OBJERR \
1770                        && FC_ERRNO(code) == FC_PROT))
1771 #   endif
1772 #   ifdef FREEBSD
1773 #     define SIG_OK (sig == SIGBUS)
1774 #     define CODE_OK (code == BUS_PAGE_FAULT)
1775 #   endif
1776 # endif
1777 # if defined(IRIX5) || defined(OSF1)
1778 #   include <errno.h>
1779     void GC_write_fault_handler(int sig, int code, struct sigcontext *scp)
1780 #   define SIG_OK (sig == SIGSEGV)
1781 #   ifdef OSF1
1782 #     define CODE_OK (code == 2 /* experimentally determined */)
1783 #   endif
1784 #   ifdef IRIX5
1785 #     define CODE_OK (code == EACCES)
1786 #   endif
1787 # endif
1788 # if defined(LINUX)
1789 #   if defined(ALPHA) || defined(M68K)
1790       void GC_write_fault_handler(int sig, int code, s_c * sc)
1791 #   else
1792 #     if defined(IA64)
1793         void GC_write_fault_handler(int sig, siginfo_t * si, s_c * scp)
1794 #     else
1795         void GC_write_fault_handler(int sig, s_c sc)
1796 #     endif
1797 #   endif
1798 #   define SIG_OK (sig == SIGSEGV)
1799 #   define CODE_OK TRUE
1800         /* Empirically c.trapno == 14, on IA32, but is that useful?     */
1801         /* Should probably consider alignment issues on other           */
1802         /* architectures.                                               */
1803 # endif
1804 # if defined(SUNOS5SIGS)
1805 #  ifdef __STDC__
1806     void GC_write_fault_handler(int sig, struct SIGINFO *scp, void * context)
1807 #  else
1808     void GC_write_fault_handler(sig, scp, context)
1809     int sig;
1810     struct SIGINFO *scp;
1811     void * context;
1812 #  endif
1813 #   ifdef HPUX
1814 #     define SIG_OK (sig == SIGSEGV || sig == SIGBUS)
1815 #     define CODE_OK (scp -> si_code == SEGV_ACCERR) \
1816                      || (scp -> si_code == BUS_ADRERR) \
1817                      || (scp -> si_code == BUS_UNKNOWN) \
1818                      || (scp -> si_code == SEGV_UNKNOWN) \
1819                      || (scp -> si_code == BUS_OBJERR)
1820 #   else
1821 #     define SIG_OK (sig == SIGSEGV)
1822 #     define CODE_OK (scp -> si_code == SEGV_ACCERR)
1823 #   endif
1824 # endif
1825 # if defined(MSWIN32)
1826     LONG WINAPI GC_write_fault_handler(struct _EXCEPTION_POINTERS *exc_info)
1827 #   define SIG_OK (exc_info -> ExceptionRecord -> ExceptionCode == \
1828                         EXCEPTION_ACCESS_VIOLATION)
1829 #   define CODE_OK (exc_info -> ExceptionRecord -> ExceptionInformation[0] == 1)
1830                         /* Write fault */
1831 # endif
1832 {
1833     register unsigned i;
1834 #   ifdef IRIX5
1835         char * addr = (char *) (size_t) (scp -> sc_badvaddr);
1836 #   endif
1837 #   if defined(OSF1) && defined(ALPHA)
1838         char * addr = (char *) (scp -> sc_traparg_a0);
1839 #   endif
1840 #   ifdef SUNOS5SIGS
1841         char * addr = (char *) (scp -> si_addr);
1842 #   endif
1843 #   ifdef LINUX
1844 #     ifdef I386
1845         char * addr = (char *) (sc.cr2);
1846 #     else
1847 #       if defined(M68K)
1848           char * addr = NULL;
1849
1850           struct sigcontext *scp = (struct sigcontext *)(&sc);
1851
1852           int format = (scp->sc_formatvec >> 12) & 0xf;
1853           unsigned long *framedata = (unsigned long *)(scp + 1);
1854           unsigned long ea;
1855
1856           if (format == 0xa || format == 0xb) {
1857                 /* 68020/030 */
1858                 ea = framedata[2];
1859           } else if (format == 7) {
1860                 /* 68040 */
1861                 ea = framedata[3];
1862           } else if (format == 4) {
1863                 /* 68060 */
1864                 ea = framedata[0];
1865                 if (framedata[1] & 0x08000000) {
1866                         /* correct addr on misaligned access */
1867                         ea = (ea+4095)&(~4095);
1868                 }
1869           }
1870           addr = (char *)ea;
1871 #       else
1872 #         ifdef ALPHA
1873             char * addr = get_fault_addr(sc);
1874 #         else
1875 #           ifdef IA64
1876               char * addr = si -> si_addr;
1877 #           else
1878 #             if defined(POWERPC)
1879                 char * addr = (char *) (sc.regs->dar);
1880 #             else
1881                 --> architecture not supported
1882 #             endif
1883 #           endif
1884 #         endif
1885 #       endif
1886 #     endif
1887 #   endif
1888 #   if defined(MSWIN32)
1889         char * addr = (char *) (exc_info -> ExceptionRecord
1890                                 -> ExceptionInformation[1]);
1891 #       define sig SIGSEGV
1892 #   endif
1893
1894     if (SIG_OK && CODE_OK) {
1895         register struct hblk * h =
1896                         (struct hblk *)((word)addr & ~(GC_page_size-1));
1897         GC_bool in_allocd_block;
1898
1899 #       ifdef SUNOS5SIGS
1900             /* Address is only within the correct physical page.        */
1901             in_allocd_block = FALSE;
1902             for (i = 0; i < divHBLKSZ(GC_page_size); i++) {
1903               if (HDR(h+i) != 0) {
1904                 in_allocd_block = TRUE;
1905               }
1906             }
1907 #       else
1908             in_allocd_block = (HDR(addr) != 0);
1909 #       endif
1910         if (!in_allocd_block) {
1911             /* Heap blocks now begin and end on page boundaries */
1912             SIG_PF old_handler;
1913
1914             if (sig == SIGSEGV) {
1915                 old_handler = GC_old_segv_handler;
1916             } else {
1917                 old_handler = GC_old_bus_handler;
1918             }
1919             if (old_handler == SIG_DFL) {
1920 #               ifndef MSWIN32
1921                     GC_err_printf1("Segfault at 0x%lx\n", addr);
1922                     ABORT("Unexpected bus error or segmentation fault");
1923 #               else
1924                     return(EXCEPTION_CONTINUE_SEARCH);
1925 #               endif
1926             } else {
1927 #               if defined (SUNOS4) || defined(FREEBSD)
1928                     (*old_handler) (sig, code, scp, addr);
1929                     return;
1930 #               endif
1931 #               if defined (SUNOS5SIGS)
1932                     (*(REAL_SIG_PF)old_handler) (sig, scp, context);
1933                     return;
1934 #               endif
1935 #               if defined (LINUX)
1936 #                   if defined(ALPHA) || defined(M68K)
1937                         (*(REAL_SIG_PF)old_handler) (sig, code, sc);
1938 #                   else
1939 #                     if defined(IA64)
1940                         (*(REAL_SIG_PF)old_handler) (sig, si, scp);
1941 #                     else
1942                         (*(REAL_SIG_PF)old_handler) (sig, sc);
1943 #                     endif
1944 #                   endif
1945                     return;
1946 #               endif
1947 #               if defined (IRIX5) || defined(OSF1)
1948                     (*(REAL_SIG_PF)old_handler) (sig, code, scp);
1949                     return;
1950 #               endif
1951 #               ifdef MSWIN32
1952                     return((*old_handler)(exc_info));
1953 #               endif
1954             }
1955         }
1956         for (i = 0; i < divHBLKSZ(GC_page_size); i++) {
1957             register int index = PHT_HASH(h+i);
1958
1959             set_pht_entry_from_index(GC_dirty_pages, index);
1960         }
1961         UNPROTECT(h, GC_page_size);
1962 #       if defined(OSF1) || defined(LINUX)
1963             /* These reset the signal handler each time by default. */
1964             signal(SIGSEGV, (SIG_PF) GC_write_fault_handler);
1965 #       endif
1966         /* The write may not take place before dirty bits are read.     */
1967         /* But then we'll fault again ...                               */
1968 #       ifdef MSWIN32
1969             return(EXCEPTION_CONTINUE_EXECUTION);
1970 #       else
1971             return;
1972 #       endif
1973     }
1974 #ifdef MSWIN32
1975     return EXCEPTION_CONTINUE_SEARCH;
1976 #else
1977     GC_err_printf1("Segfault at 0x%lx\n", addr);
1978     ABORT("Unexpected bus error or segmentation fault");
1979 #endif
1980 }
1981
1982 /*
1983  * We hold the allocation lock.  We expect block h to be written
1984  * shortly.
1985  */
1986 void GC_write_hint(h)
1987 struct hblk *h;
1988 {
1989     register struct hblk * h_trunc;
1990     register unsigned i;
1991     register GC_bool found_clean;
1992
1993     if (!GC_dirty_maintained) return;
1994     h_trunc = (struct hblk *)((word)h & ~(GC_page_size-1));
1995     found_clean = FALSE;
1996     for (i = 0; i < divHBLKSZ(GC_page_size); i++) {
1997         register int index = PHT_HASH(h_trunc+i);
1998
1999         if (!get_pht_entry_from_index(GC_dirty_pages, index)) {
2000             found_clean = TRUE;
2001             set_pht_entry_from_index(GC_dirty_pages, index);
2002         }
2003     }
2004     if (found_clean) {
2005         UNPROTECT(h_trunc, GC_page_size);
2006     }
2007 }
2008
2009 void GC_dirty_init()
2010 {
2011 #if defined(SUNOS5SIGS) || defined(IRIX5) /* || defined(OSF1) */
2012     struct sigaction    act, oldact;
2013 #   ifdef IRIX5
2014         act.sa_flags    = SA_RESTART;
2015         act.sa_handler  = GC_write_fault_handler;
2016 #   else
2017         act.sa_flags    = SA_RESTART | SA_SIGINFO;
2018         act.sa_sigaction = GC_write_fault_handler;
2019 #   endif
2020     (void)sigemptyset(&act.sa_mask);
2021 #endif
2022 #   ifdef PRINTSTATS
2023         GC_printf0("Inititalizing mprotect virtual dirty bit implementation\n");
2024 #   endif
2025     GC_dirty_maintained = TRUE;
2026     if (GC_page_size % HBLKSIZE != 0) {
2027         GC_err_printf0("Page size not multiple of HBLKSIZE\n");
2028         ABORT("Page size not multiple of HBLKSIZE");
2029     }
2030 #   if defined(SUNOS4) || defined(FREEBSD)
2031       GC_old_bus_handler = signal(SIGBUS, GC_write_fault_handler);
2032       if (GC_old_bus_handler == SIG_IGN) {
2033         GC_err_printf0("Previously ignored bus error!?");
2034         GC_old_bus_handler = SIG_DFL;
2035       }
2036       if (GC_old_bus_handler != SIG_DFL) {
2037 #       ifdef PRINTSTATS
2038           GC_err_printf0("Replaced other SIGBUS handler\n");
2039 #       endif
2040       }
2041 #   endif
2042 #   if defined(OSF1) || defined(SUNOS4) || defined(LINUX)
2043       GC_old_segv_handler = signal(SIGSEGV, (SIG_PF)GC_write_fault_handler);
2044       if (GC_old_segv_handler == SIG_IGN) {
2045         GC_err_printf0("Previously ignored segmentation violation!?");
2046         GC_old_segv_handler = SIG_DFL;
2047       }
2048       if (GC_old_segv_handler != SIG_DFL) {
2049 #       ifdef PRINTSTATS
2050           GC_err_printf0("Replaced other SIGSEGV handler\n");
2051 #       endif
2052       }
2053 #   endif
2054 #   if defined(SUNOS5SIGS) || defined(IRIX5)
2055 #     if defined(IRIX_THREADS) || defined(IRIX_JDK_THREADS)
2056         sigaction(SIGSEGV, 0, &oldact);
2057         sigaction(SIGSEGV, &act, 0);
2058 #     else
2059         sigaction(SIGSEGV, &act, &oldact);
2060 #     endif
2061 #     if defined(_sigargs)
2062         /* This is Irix 5.x, not 6.x.  Irix 5.x does not have   */
2063         /* sa_sigaction.                                        */
2064         GC_old_segv_handler = oldact.sa_handler;
2065 #     else /* Irix 6.x or SUNOS5SIGS */
2066         if (oldact.sa_flags & SA_SIGINFO) {
2067           GC_old_segv_handler = (SIG_PF)(oldact.sa_sigaction);
2068         } else {
2069           GC_old_segv_handler = oldact.sa_handler;
2070         }
2071 #     endif
2072       if (GC_old_segv_handler == SIG_IGN) {
2073              GC_err_printf0("Previously ignored segmentation violation!?");
2074              GC_old_segv_handler = SIG_DFL;
2075       }
2076       if (GC_old_segv_handler != SIG_DFL) {
2077 #       ifdef PRINTSTATS
2078           GC_err_printf0("Replaced other SIGSEGV handler\n");
2079 #       endif
2080       }
2081 #     ifdef HPUX
2082           sigaction(SIGBUS, &act, &oldact);
2083           GC_old_bus_handler = oldact.sa_handler;
2084           if (GC_old_segv_handler != SIG_DFL) {
2085 #           ifdef PRINTSTATS
2086               GC_err_printf0("Replaced other SIGBUS handler\n");
2087 #           endif
2088           }
2089 #     endif
2090 #    endif
2091 #   if defined(MSWIN32)
2092       GC_old_segv_handler = SetUnhandledExceptionFilter(GC_write_fault_handler);
2093       if (GC_old_segv_handler != NULL) {
2094 #       ifdef PRINTSTATS
2095           GC_err_printf0("Replaced other UnhandledExceptionFilter\n");
2096 #       endif
2097       } else {
2098           GC_old_segv_handler = SIG_DFL;
2099       }
2100 #   endif
2101 }
2102
2103
2104
2105 void GC_protect_heap()
2106 {
2107     ptr_t start;
2108     word len;
2109     unsigned i;
2110
2111     for (i = 0; i < GC_n_heap_sects; i++) {
2112         start = GC_heap_sects[i].hs_start;
2113         len = GC_heap_sects[i].hs_bytes;
2114         PROTECT(start, len);
2115     }
2116 }
2117
2118 /* We assume that either the world is stopped or its OK to lose dirty   */
2119 /* bits while this is happenning (as in GC_enable_incremental).         */
2120 void GC_read_dirty()
2121 {
2122     BCOPY((word *)GC_dirty_pages, GC_grungy_pages,
2123           (sizeof GC_dirty_pages));
2124     BZERO((word *)GC_dirty_pages, (sizeof GC_dirty_pages));
2125     GC_protect_heap();
2126 }
2127
2128 GC_bool GC_page_was_dirty(h)
2129 struct hblk * h;
2130 {
2131     register word index = PHT_HASH(h);
2132
2133     return(HDR(h) == 0 || get_pht_entry_from_index(GC_grungy_pages, index));
2134 }
2135
2136 /*
2137  * Acquiring the allocation lock here is dangerous, since this
2138  * can be called from within GC_call_with_alloc_lock, and the cord
2139  * package does so.  On systems that allow nested lock acquisition, this
2140  * happens to work.
2141  * On other systems, SET_LOCK_HOLDER and friends must be suitably defined.
2142  */
2143
2144 void GC_begin_syscall()
2145 {
2146     if (!I_HOLD_LOCK()) LOCK();
2147 }
2148
2149 void GC_end_syscall()
2150 {
2151     if (!I_HOLD_LOCK()) UNLOCK();
2152 }
2153
2154 void GC_unprotect_range(addr, len)
2155 ptr_t addr;
2156 word len;
2157 {
2158     struct hblk * start_block;
2159     struct hblk * end_block;
2160     register struct hblk *h;
2161     ptr_t obj_start;
2162
2163     if (!GC_incremental) return;
2164     obj_start = GC_base(addr);
2165     if (obj_start == 0) return;
2166     if (GC_base(addr + len - 1) != obj_start) {
2167         ABORT("GC_unprotect_range(range bigger than object)");
2168     }
2169     start_block = (struct hblk *)((word)addr & ~(GC_page_size - 1));
2170     end_block = (struct hblk *)((word)(addr + len - 1) & ~(GC_page_size - 1));
2171     end_block += GC_page_size/HBLKSIZE - 1;
2172     for (h = start_block; h <= end_block; h++) {
2173         register word index = PHT_HASH(h);
2174
2175         set_pht_entry_from_index(GC_dirty_pages, index);
2176     }
2177     UNPROTECT(start_block,
2178               ((ptr_t)end_block - (ptr_t)start_block) + HBLKSIZE);
2179 }
2180
2181 #ifndef MSWIN32
2182 /* Replacement for UNIX system call.     */
2183 /* Other calls that write to the heap    */
2184 /* should be handled similarly.          */
2185 # if defined(__STDC__) && !defined(SUNOS4)
2186 #   include <unistd.h>
2187     ssize_t read(int fd, void *buf, size_t nbyte)
2188 # else
2189 #   ifndef LINT
2190       int read(fd, buf, nbyte)
2191 #   else
2192       int GC_read(fd, buf, nbyte)
2193 #   endif
2194     int fd;
2195     char *buf;
2196     int nbyte;
2197 # endif
2198 {
2199     int result;
2200
2201     GC_begin_syscall();
2202     GC_unprotect_range(buf, (word)nbyte);
2203 #   ifdef IRIX5
2204         /* Indirect system call may not always be easily available.     */
2205         /* We could call _read, but that would interfere with the       */
2206         /* libpthread interception of read.                             */
2207         {
2208             struct iovec iov;
2209
2210             iov.iov_base = buf;
2211             iov.iov_len = nbyte;
2212             result = readv(fd, &iov, 1);
2213         }
2214 #   else
2215         result = syscall(SYS_read, fd, buf, nbyte);
2216 #   endif
2217     GC_end_syscall();
2218     return(result);
2219 }
2220 #endif /* !MSWIN32 */
2221
2222 /*ARGSUSED*/
2223 GC_bool GC_page_was_ever_dirty(h)
2224 struct hblk *h;
2225 {
2226     return(TRUE);
2227 }
2228
2229 /* Reset the n pages starting at h to "was never dirty" status. */
2230 /*ARGSUSED*/
2231 void GC_is_fresh(h, n)
2232 struct hblk *h;
2233 word n;
2234 {
2235 }
2236
2237 # endif /* MPROTECT_VDB */
2238
2239 # ifdef PROC_VDB
2240
2241 /*
2242  * See DEFAULT_VDB for interface descriptions.
2243  */
2244
2245 /*
2246  * This implementaion assumes a Solaris 2.X like /proc pseudo-file-system
2247  * from which we can read page modified bits.  This facility is far from
2248  * optimal (e.g. we would like to get the info for only some of the
2249  * address space), but it avoids intercepting system calls.
2250  */
2251
2252 #include <errno.h>
2253 #include <sys/types.h>
2254 #include <sys/signal.h>
2255 #include <sys/fault.h>
2256 #include <sys/syscall.h>
2257 #include <sys/procfs.h>
2258 #include <sys/stat.h>
2259 #include <fcntl.h>
2260
2261 #define INITIAL_BUF_SZ 4096
2262 word GC_proc_buf_size = INITIAL_BUF_SZ;
2263 char *GC_proc_buf;
2264
2265 #ifdef SOLARIS_THREADS
2266 /* We don't have exact sp values for threads.  So we count on   */
2267 /* occasionally declaring stack pages to be fresh.  Thus we     */
2268 /* need a real implementation of GC_is_fresh.  We can't clear   */
2269 /* entries in GC_written_pages, since that would declare all    */
2270 /* pages with the given hash address to be fresh.               */
2271 #   define MAX_FRESH_PAGES 8*1024       /* Must be power of 2 */
2272     struct hblk ** GC_fresh_pages;      /* A direct mapped cache.       */
2273                                         /* Collisions are dropped.      */
2274
2275 #   define FRESH_PAGE_SLOT(h) (divHBLKSZ((word)(h)) & (MAX_FRESH_PAGES-1))
2276 #   define ADD_FRESH_PAGE(h) \
2277         GC_fresh_pages[FRESH_PAGE_SLOT(h)] = (h)
2278 #   define PAGE_IS_FRESH(h) \
2279         (GC_fresh_pages[FRESH_PAGE_SLOT(h)] == (h) && (h) != 0)
2280 #endif
2281
2282 /* Add all pages in pht2 to pht1 */
2283 void GC_or_pages(pht1, pht2)
2284 page_hash_table pht1, pht2;
2285 {
2286     register int i;
2287
2288     for (i = 0; i < PHT_SIZE; i++) pht1[i] |= pht2[i];
2289 }
2290
2291 int GC_proc_fd;
2292
2293 void GC_dirty_init()
2294 {
2295     int fd;
2296     char buf[30];
2297
2298     GC_dirty_maintained = TRUE;
2299     if (GC_words_allocd != 0 || GC_words_allocd_before_gc != 0) {
2300         register int i;
2301
2302         for (i = 0; i < PHT_SIZE; i++) GC_written_pages[i] = (word)(-1);
2303 #       ifdef PRINTSTATS
2304             GC_printf1("Allocated words:%lu:all pages may have been written\n",
2305                        (unsigned long)
2306                                 (GC_words_allocd + GC_words_allocd_before_gc));
2307 #       endif
2308     }
2309     sprintf(buf, "/proc/%d", getpid());
2310     fd = open(buf, O_RDONLY);
2311     if (fd < 0) {
2312         ABORT("/proc open failed");
2313     }
2314     GC_proc_fd = syscall(SYS_ioctl, fd, PIOCOPENPD, 0);
2315     close(fd);
2316     if (GC_proc_fd < 0) {
2317         ABORT("/proc ioctl failed");
2318     }
2319     GC_proc_buf = GC_scratch_alloc(GC_proc_buf_size);
2320 #   ifdef SOLARIS_THREADS
2321         GC_fresh_pages = (struct hblk **)
2322           GC_scratch_alloc(MAX_FRESH_PAGES * sizeof (struct hblk *));
2323         if (GC_fresh_pages == 0) {
2324             GC_err_printf0("No space for fresh pages\n");
2325             EXIT();
2326         }
2327         BZERO(GC_fresh_pages, MAX_FRESH_PAGES * sizeof (struct hblk *));
2328 #   endif
2329 }
2330
2331 /* Ignore write hints. They don't help us here. */
2332 /*ARGSUSED*/
2333 void GC_write_hint(h)
2334 struct hblk *h;
2335 {
2336 }
2337
2338 #ifdef SOLARIS_THREADS
2339 #   define READ(fd,buf,nbytes) syscall(SYS_read, fd, buf, nbytes)
2340 #else
2341 #   define READ(fd,buf,nbytes) read(fd, buf, nbytes)
2342 #endif
2343
2344 void GC_read_dirty()
2345 {
2346     unsigned long ps, np;
2347     int nmaps;
2348     ptr_t vaddr;
2349     struct prasmap * map;
2350     char * bufp;
2351     ptr_t current_addr, limit;
2352     int i;
2353 int dummy;
2354
2355     BZERO(GC_grungy_pages, (sizeof GC_grungy_pages));
2356
2357     bufp = GC_proc_buf;
2358     if (READ(GC_proc_fd, bufp, GC_proc_buf_size) <= 0) {
2359 #       ifdef PRINTSTATS
2360             GC_printf1("/proc read failed: GC_proc_buf_size = %lu\n",
2361                        GC_proc_buf_size);
2362 #       endif
2363         {
2364             /* Retry with larger buffer. */
2365             word new_size = 2 * GC_proc_buf_size;
2366             char * new_buf = GC_scratch_alloc(new_size);
2367
2368             if (new_buf != 0) {
2369                 GC_proc_buf = bufp = new_buf;
2370                 GC_proc_buf_size = new_size;
2371             }
2372             if (syscall(SYS_read, GC_proc_fd, bufp, GC_proc_buf_size) <= 0) {
2373                 WARN("Insufficient space for /proc read\n", 0);
2374                 /* Punt:        */
2375                 memset(GC_grungy_pages, 0xff, sizeof (page_hash_table));
2376                 memset(GC_written_pages, 0xff, sizeof(page_hash_table));
2377 #               ifdef SOLARIS_THREADS
2378                     BZERO(GC_fresh_pages,
2379                           MAX_FRESH_PAGES * sizeof (struct hblk *));
2380 #               endif
2381                 return;
2382             }
2383         }
2384     }
2385     /* Copy dirty bits into GC_grungy_pages */
2386         nmaps = ((struct prpageheader *)bufp) -> pr_nmap;
2387         /* printf( "nmaps = %d, PG_REFERENCED = %d, PG_MODIFIED = %d\n",
2388                      nmaps, PG_REFERENCED, PG_MODIFIED); */
2389         bufp = bufp + sizeof(struct prpageheader);
2390         for (i = 0; i < nmaps; i++) {
2391             map = (struct prasmap *)bufp;
2392             vaddr = (ptr_t)(map -> pr_vaddr);
2393             ps = map -> pr_pagesize;
2394             np = map -> pr_npage;
2395             /* printf("vaddr = 0x%X, ps = 0x%X, np = 0x%X\n", vaddr, ps, np); */
2396             limit = vaddr + ps * np;
2397             bufp += sizeof (struct prasmap);
2398             for (current_addr = vaddr;
2399                  current_addr < limit; current_addr += ps){
2400                 if ((*bufp++) & PG_MODIFIED) {
2401                     register struct hblk * h = (struct hblk *) current_addr;
2402
2403                     while ((ptr_t)h < current_addr + ps) {
2404                         register word index = PHT_HASH(h);
2405
2406                         set_pht_entry_from_index(GC_grungy_pages, index);
2407 #                       ifdef SOLARIS_THREADS
2408                           {
2409                             register int slot = FRESH_PAGE_SLOT(h);
2410
2411                             if (GC_fresh_pages[slot] == h) {
2412                                 GC_fresh_pages[slot] = 0;
2413                             }
2414                           }
2415 #                       endif
2416                         h++;
2417                     }
2418                 }
2419             }
2420             bufp += sizeof(long) - 1;
2421             bufp = (char *)((unsigned long)bufp & ~(sizeof(long)-1));
2422         }
2423     /* Update GC_written_pages. */
2424         GC_or_pages(GC_written_pages, GC_grungy_pages);
2425 #   ifdef SOLARIS_THREADS
2426       /* Make sure that old stacks are considered completely clean      */
2427       /* unless written again.                                          */
2428         GC_old_stacks_are_fresh();
2429 #   endif
2430 }
2431
2432 #undef READ
2433
2434 GC_bool GC_page_was_dirty(h)
2435 struct hblk *h;
2436 {
2437     register word index = PHT_HASH(h);
2438     register GC_bool result;
2439
2440     result = get_pht_entry_from_index(GC_grungy_pages, index);
2441 #   ifdef SOLARIS_THREADS
2442         if (result && PAGE_IS_FRESH(h)) result = FALSE;
2443         /* This happens only if page was declared fresh since   */
2444         /* the read_dirty call, e.g. because it's in an unused  */
2445         /* thread stack.  It's OK to treat it as clean, in      */
2446         /* that case.  And it's consistent with                 */
2447         /* GC_page_was_ever_dirty.                              */
2448 #   endif
2449     return(result);
2450 }
2451
2452 GC_bool GC_page_was_ever_dirty(h)
2453 struct hblk *h;
2454 {
2455     register word index = PHT_HASH(h);
2456     register GC_bool result;
2457
2458     result = get_pht_entry_from_index(GC_written_pages, index);
2459 #   ifdef SOLARIS_THREADS
2460         if (result && PAGE_IS_FRESH(h)) result = FALSE;
2461 #   endif
2462     return(result);
2463 }
2464
2465 /* Caller holds allocation lock.        */
2466 void GC_is_fresh(h, n)
2467 struct hblk *h;
2468 word n;
2469 {
2470
2471     register word index;
2472
2473 #   ifdef SOLARIS_THREADS
2474       register word i;
2475
2476       if (GC_fresh_pages != 0) {
2477         for (i = 0; i < n; i++) {
2478           ADD_FRESH_PAGE(h + i);
2479         }
2480       }
2481 #   endif
2482 }
2483
2484 # endif /* PROC_VDB */
2485
2486
2487 # ifdef PCR_VDB
2488
2489 # include "vd/PCR_VD.h"
2490
2491 # define NPAGES (32*1024)       /* 128 MB */
2492
2493 PCR_VD_DB  GC_grungy_bits[NPAGES];
2494
2495 ptr_t GC_vd_base;       /* Address corresponding to GC_grungy_bits[0]   */
2496                         /* HBLKSIZE aligned.                            */
2497
2498 void GC_dirty_init()
2499 {
2500     GC_dirty_maintained = TRUE;
2501     /* For the time being, we assume the heap generally grows up */
2502     GC_vd_base = GC_heap_sects[0].hs_start;
2503     if (GC_vd_base == 0) {
2504         ABORT("Bad initial heap segment");
2505     }
2506     if (PCR_VD_Start(HBLKSIZE, GC_vd_base, NPAGES*HBLKSIZE)
2507         != PCR_ERes_okay) {
2508         ABORT("dirty bit initialization failed");
2509     }
2510 }
2511
2512 void GC_read_dirty()
2513 {
2514     /* lazily enable dirty bits on newly added heap sects */
2515     {
2516         static int onhs = 0;
2517         int nhs = GC_n_heap_sects;
2518         for( ; onhs < nhs; onhs++ ) {
2519             PCR_VD_WriteProtectEnable(
2520                     GC_heap_sects[onhs].hs_start,
2521                     GC_heap_sects[onhs].hs_bytes );
2522         }
2523     }
2524
2525
2526     if (PCR_VD_Clear(GC_vd_base, NPAGES*HBLKSIZE, GC_grungy_bits)
2527         != PCR_ERes_okay) {
2528         ABORT("dirty bit read failed");
2529     }
2530 }
2531
2532 GC_bool GC_page_was_dirty(h)
2533 struct hblk *h;
2534 {
2535     if((ptr_t)h < GC_vd_base || (ptr_t)h >= GC_vd_base + NPAGES*HBLKSIZE) {
2536         return(TRUE);
2537     }
2538     return(GC_grungy_bits[h - (struct hblk *)GC_vd_base] & PCR_VD_DB_dirtyBit);
2539 }
2540
2541 /*ARGSUSED*/
2542 void GC_write_hint(h)
2543 struct hblk *h;
2544 {
2545     PCR_VD_WriteProtectDisable(h, HBLKSIZE);
2546     PCR_VD_WriteProtectEnable(h, HBLKSIZE);
2547 }
2548
2549 # endif /* PCR_VDB */
2550
2551 /*
2552  * Call stack save code for debugging.
2553  * Should probably be in mach_dep.c, but that requires reorganization.
2554  */
2555 #if defined(SPARC) && !defined(LINUX)
2556 #   if defined(SUNOS4)
2557 #     include <machine/frame.h>
2558 #   else
2559 #     if defined (DRSNX)
2560 #       include <sys/sparc/frame.h>
2561 #     else
2562 #        if defined(OPENBSD)
2563 #          include <frame.h>
2564 #        else
2565 #          include <sys/frame.h>
2566 #        endif
2567 #     endif
2568 #   endif
2569 #   if NARGS > 6
2570         --> We only know how to to get the first 6 arguments
2571 #   endif
2572
2573 #ifdef SAVE_CALL_CHAIN
2574 /* Fill in the pc and argument information for up to NFRAMES of my      */
2575 /* callers.  Ignore my frame and my callers frame.                      */
2576
2577 #ifdef OPENBSD
2578 #  define FR_SAVFP fr_fp
2579 #  define FR_SAVPC fr_pc
2580 #else
2581 #  define FR_SAVFP fr_savfp
2582 #  define FR_SAVPC fr_savpc
2583 #endif
2584
2585 void GC_save_callers (info)
2586 struct callinfo info[NFRAMES];
2587 {
2588   struct frame *frame;
2589   struct frame *fp;
2590   int nframes = 0;
2591   word GC_save_regs_in_stack();
2592
2593   frame = (struct frame *) GC_save_regs_in_stack ();
2594
2595   for (fp = frame -> FR_SAVFP; fp != 0 && nframes < NFRAMES;
2596        fp = fp -> FR_SAVFP, nframes++) {
2597       register int i;
2598
2599       info[nframes].ci_pc = fp->FR_SAVPC;
2600       for (i = 0; i < NARGS; i++) {
2601         info[nframes].ci_arg[i] = ~(fp->fr_arg[i]);
2602       }
2603   }
2604   if (nframes < NFRAMES) info[nframes].ci_pc = 0;
2605 }
2606
2607 #endif /* SAVE_CALL_CHAIN */
2608 #endif /* SPARC */
2609
2610
2611