dbg_mlc.c

/* 
 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
 * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
 * Copyright (c) 1997 by Silicon Graphics.  All rights reserved.
 * Copyright (c) 1999-2004 Hewlett-Packard Development Company, L.P.
 * Copyright (C) 2007 Free Software Foundation, Inc
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to use or copy this program
 * for any purpose,  provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 */

#include "private/dbg_mlc.h"

void GC_default_print_heap_obj_proc();
GC_API void GC_register_finalizer_no_order
    	GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
		  GC_finalization_proc *ofn, GC_PTR *ocd));


#ifndef SHORT_DBG_HDRS
/* Check whether object with base pointer p has debugging info	*/ 
/* p is assumed to point to a legitimate object in our part	*/
/* of the heap.							*/
/* This excludes the check as to whether the back pointer is 	*/
/* odd, which is added by the GC_HAS_DEBUG_INFO macro.		*/
/* Note that if DBG_HDRS_ALL is set, uncollectable objects	*/
/* on free lists may not have debug information set.  Thus it's	*/
/* not always safe to return TRUE, even if the client does	*/
/* its part.							*/
GC_bool GC_has_other_debug_info(p)
ptr_t p;
{
    register oh * ohdr = (oh *)p;
    register ptr_t body = (ptr_t)(ohdr + 1);
    register word sz = GC_size((ptr_t) ohdr);
    
    if (HBLKPTR((ptr_t)ohdr) != HBLKPTR((ptr_t)body)
        || sz < DEBUG_BYTES + EXTRA_BYTES) {
        return(FALSE);
    }
    if (ohdr -> oh_sz == sz) {
    	/* Object may have had debug info, but has been deallocated	*/
    	return(FALSE);
    }
    if (ohdr -> oh_sf == (START_FLAG ^ (word)body)) return(TRUE);
    if (((word *)ohdr)[BYTES_TO_WORDS(sz)-1] == (END_FLAG ^ (word)body)) {
        return(TRUE);
    }
    return(FALSE);
}
#endif

#ifdef KEEP_BACK_PTRS

# include <stdlib.h>

# if defined(LINUX) || defined(SUNOS4) || defined(SUNOS5) \
     || defined(HPUX) || defined(IRIX5) || defined(OSF1)
#   define RANDOM() random()
# else
#   define RANDOM() (long)rand()
# endif

  /* Store back pointer to source in dest, if that appears to be possible. */
  /* This is not completely safe, since we may mistakenly conclude that	   */
  /* dest has a debugging wrapper.  But the error probability is very	   */
  /* small, and this shouldn't be used in production code.		   */
  /* We assume that dest is the real base pointer.  Source will usually    */
  /* be a pointer to the interior of an object.				   */
  void GC_store_back_pointer(ptr_t source, ptr_t dest)
  {
    if (GC_HAS_DEBUG_INFO(dest)) {
      ((oh *)dest) -> oh_back_ptr = HIDE_BACK_PTR(source);
    }
  }

  void GC_marked_for_finalization(ptr_t dest) {
    GC_store_back_pointer(MARKED_FOR_FINALIZATION, dest);
  }

  /* Store information about the object referencing dest in *base_p	*/
  /* and *offset_p.							*/
  /*   source is root ==> *base_p = address, *offset_p = 0		*/
  /*   source is heap object ==> *base_p != 0, *offset_p = offset 	*/
  /*   Returns 1 on success, 0 if source couldn't be determined.	*/
  /* Dest can be any address within a heap object.			*/
  GC_ref_kind GC_get_back_ptr_info(void *dest, void **base_p, size_t *offset_p)
  {
    oh * hdr = (oh *)GC_base(dest);
    ptr_t bp;
    ptr_t bp_base;
    if (!GC_HAS_DEBUG_INFO((ptr_t) hdr)) return GC_NO_SPACE;
    bp = REVEAL_POINTER(hdr -> oh_back_ptr);
    if (MARKED_FOR_FINALIZATION == bp) return GC_FINALIZER_REFD;
    if (MARKED_FROM_REGISTER == bp) return GC_REFD_FROM_REG;
    if (NOT_MARKED == bp) return GC_UNREFERENCED;
#   if ALIGNMENT == 1
      /* Heuristically try to fix off by 1 errors we introduced by 	*/
      /* insisting on even addresses.					*/
      {
	ptr_t alternate_ptr = bp + 1;
	ptr_t target = *(ptr_t *)bp;
	ptr_t alternate_target = *(ptr_t *)alternate_ptr;

	if (alternate_target >= GC_least_plausible_heap_addr
	    && alternate_target <= GC_greatest_plausible_heap_addr
	    && (target < GC_least_plausible_heap_addr
		|| target > GC_greatest_plausible_heap_addr)) {
	    bp = alternate_ptr;
	}
      }
#   endif
    bp_base = GC_base(bp);
    if (0 == bp_base) {
      *base_p = bp;
      *offset_p = 0;
      return GC_REFD_FROM_ROOT;
    } else {
      if (GC_HAS_DEBUG_INFO(bp_base)) bp_base += sizeof(oh);
      *base_p = bp_base;
      *offset_p = bp - bp_base;
      return GC_REFD_FROM_HEAP;
    }
  }

  /* Generate a random heap address.		*/
  /* The resulting address is in the heap, but	*/
  /* not necessarily inside a valid object.	*/
  void *GC_generate_random_heap_address(void)
  {
    int i;
    long heap_offset = RANDOM();
    if (GC_heapsize > RAND_MAX) {
	heap_offset *= RAND_MAX;
	heap_offset += RANDOM();
    }
    heap_offset %= GC_heapsize;
    	/* This doesn't yield a uniform distribution, especially if	*/
        /* e.g. RAND_MAX = 1.5* GC_heapsize.  But for typical cases,	*/
        /* it's not too bad.						*/
    for (i = 0; i < GC_n_heap_sects; ++ i) {
	int size = GC_heap_sects[i].hs_bytes;
	if (heap_offset < size) {
	    return GC_heap_sects[i].hs_start + heap_offset;
	} else {
	    heap_offset -= size;
	}
    }
    ABORT("GC_generate_random_heap_address: size inconsistency");
    /*NOTREACHED*/
    return 0;
  }

  /* Generate a random address inside a valid marked heap object. */
  void *GC_generate_random_valid_address(void)
  {
    ptr_t result;
    ptr_t base;
    for (;;) {
	result = GC_generate_random_heap_address();
  	base = GC_base(result);
	if (0 == base) continue;
	if (!GC_is_marked(base)) continue;
	return result;
    }
  }

  /* Print back trace for p */
  void GC_print_backtrace(void *p)
  {
    void *current = p;
    int i;
    GC_ref_kind source;
    size_t offset;
    void *base;

    GC_print_heap_obj(GC_base(current));
    GC_err_printf0("\n");
    for (i = 0; ; ++i) {
      source = GC_get_back_ptr_info(current, &base, &offset);
      if (GC_UNREFERENCED == source) {
	GC_err_printf0("Reference could not be found\n");
  	goto out;
      }
      if (GC_NO_SPACE == source) {
	GC_err_printf0("No debug info in object: Can't find reference\n");
	goto out;
      }
      GC_err_printf1("Reachable via %d levels of pointers from ",
		 (unsigned long)i);
      switch(source) {
	case GC_REFD_FROM_ROOT:
	  GC_err_printf1("root at 0x%lx\n\n", (unsigned long)base);
	  goto out;
	case GC_REFD_FROM_REG:
	  GC_err_printf0("root in register\n\n");
	  goto out;
	case GC_FINALIZER_REFD:
	  GC_err_printf0("list of finalizable objects\n\n");
	  goto out;
	case GC_REFD_FROM_HEAP:
	  GC_err_printf1("offset %ld in object:\n", (unsigned long)offset);
	  /* Take GC_base(base) to get real base, i.e. header. */
	  GC_print_heap_obj(GC_base(base));
	  GC_err_printf0("\n");
	  break;
      }
      current = base;
    }
    out:;
  }

  /* Force a garbage collection and generate a backtrace from a	*/
  /* random heap address.					*/
  void GC_generate_random_backtrace_no_gc(void)
  {
    void * current;
    current = GC_generate_random_valid_address();
    GC_printf1("\n****Chose address 0x%lx in object\n", (unsigned long)current);
    GC_print_backtrace(current);
  }
    
  void GC_generate_random_backtrace(void)
  {
    GC_gcollect();
    GC_generate_random_backtrace_no_gc();
  }
    
#endif /* KEEP_BACK_PTRS */

# define CROSSES_HBLK(p, sz) \
	(((word)(p + sizeof(oh) + sz - 1) ^ (word)p) >= HBLKSIZE)
/* Store debugging info into p.  Return displaced pointer. */
/* Assumes we don't hold allocation lock.		   */
ptr_t GC_store_debug_info(p, sz, string, integer)
register ptr_t p;	/* base pointer */
word sz; 	/* bytes */
GC_CONST char * string;
word integer;
{
    register word * result = (word *)((oh *)p + 1);
    DCL_LOCK_STATE;
    
    /* There is some argument that we should dissble signals here.	*/
    /* But that's expensive.  And this way things should only appear	*/
    /* inconsistent while we're in the handler.				*/
    LOCK();
    GC_ASSERT(GC_size(p) >= sizeof(oh) + sz);
    GC_ASSERT(!(SMALL_OBJ(sz) && CROSSES_HBLK(p, sz)));
#   ifdef KEEP_BACK_PTRS
      ((oh *)p) -> oh_back_ptr = HIDE_BACK_PTR(NOT_MARKED);
#   endif
#   ifdef MAKE_BACK_GRAPH
      ((oh *)p) -> oh_bg_ptr = HIDE_BACK_PTR((ptr_t)0);
#   endif
    ((oh *)p) -> oh_string = string;
    ((oh *)p) -> oh_int = integer;
#   ifndef SHORT_DBG_HDRS
      ((oh *)p) -> oh_sz = sz;
      ((oh *)p) -> oh_sf = START_FLAG ^ (word)result;
      ((word *)p)[BYTES_TO_WORDS(GC_size(p))-1] =
         result[SIMPLE_ROUNDED_UP_WORDS(sz)] = END_FLAG ^ (word)result;
#   endif
    UNLOCK();
    return((ptr_t)result);
}

#ifdef DBG_HDRS_ALL
/* Store debugging info into p.  Return displaced pointer.	   */
/* This version assumes we do hold the allocation lock.		   */
ptr_t GC_store_debug_info_inner(p, sz, string, integer)
register ptr_t p;	/* base pointer */
word sz; 	/* bytes */
char * string;
word integer;
{
    register word * result = (word *)((oh *)p + 1);
    
    /* There is some argument that we should disable signals here.	*/
    /* But that's expensive.  And this way things should only appear	*/
    /* inconsistent while we're in the handler.				*/
    GC_ASSERT(GC_size(p) >= sizeof(oh) + sz);
    GC_ASSERT(!(SMALL_OBJ(sz) && CROSSES_HBLK(p, sz)));
#   ifdef KEEP_BACK_PTRS
      ((oh *)p) -> oh_back_ptr = HIDE_BACK_PTR(NOT_MARKED);
#   endif
#   ifdef MAKE_BACK_GRAPH
      ((oh *)p) -> oh_bg_ptr = HIDE_BACK_PTR((ptr_t)0);
#   endif
    ((oh *)p) -> oh_string = string;
    ((oh *)p) -> oh_int = integer;
#   ifndef SHORT_DBG_HDRS
      ((oh *)p) -> oh_sz = sz;
      ((oh *)p) -> oh_sf = START_FLAG ^ (word)result;
      ((word *)p)[BYTES_TO_WORDS(GC_size(p))-1] =
         result[SIMPLE_ROUNDED_UP_WORDS(sz)] = END_FLAG ^ (word)result;
#   endif
    return((ptr_t)result);
}
#endif

#ifndef SHORT_DBG_HDRS
/* Check the object with debugging info at ohdr		*/
/* return NIL if it's OK.  Else return clobbered	*/
/* address.						*/
ptr_t GC_check_annotated_obj(ohdr)
register oh * ohdr;
{
    register ptr_t body = (ptr_t)(ohdr + 1);
    register word gc_sz = GC_size((ptr_t)ohdr);
    if (ohdr -> oh_sz + DEBUG_BYTES > gc_sz) {
        return((ptr_t)(&(ohdr -> oh_sz)));
    }
    if (ohdr -> oh_sf != (START_FLAG ^ (word)body)) {
        return((ptr_t)(&(ohdr -> oh_sf)));
    }
    if (((word *)ohdr)[BYTES_TO_WORDS(gc_sz)-1] != (END_FLAG ^ (word)body)) {
        return((ptr_t)((word *)ohdr + BYTES_TO_WORDS(gc_sz)-1));
    }
    if (((word *)body)[SIMPLE_ROUNDED_UP_WORDS(ohdr -> oh_sz)]
        != (END_FLAG ^ (word)body)) {
        return((ptr_t)((word *)body + SIMPLE_ROUNDED_UP_WORDS(ohdr -> oh_sz)));
    }
    return(0);
}
#endif /* !SHORT_DBG_HDRS */

static GC_describe_type_fn GC_describe_type_fns[MAXOBJKINDS] = {0};

void GC_register_describe_type_fn(kind, fn)
int kind;
GC_describe_type_fn fn;
{
  GC_describe_type_fns[kind] = fn;
}

/* Print a type description for the object whose client-visible address	*/
/* is p.								*/
void GC_print_type(p)
ptr_t p;
{
    hdr * hhdr = GC_find_header(p);
    char buffer[GC_TYPE_DESCR_LEN + 1];
    int kind = hhdr -> hb_obj_kind;

    if (0 != GC_describe_type_fns[kind] && GC_is_marked(GC_base(p))) {
	/* This should preclude free list objects except with	*/
	/* thread-local allocation.				*/
	buffer[GC_TYPE_DESCR_LEN] = 0;
	(GC_describe_type_fns[kind])(p, buffer);
	GC_ASSERT(buffer[GC_TYPE_DESCR_LEN] == 0);
	GC_err_puts(buffer);
    } else {
	switch(kind) {
	  case PTRFREE:
	    GC_err_puts("PTRFREE");
	    break;
	  case NORMAL:
	    GC_err_puts("NORMAL");
	    break;
	  case UNCOLLECTABLE:
	    GC_err_puts("UNCOLLECTABLE");
	    break;
#	  ifdef ATOMIC_UNCOLLECTABLE
	    case AUNCOLLECTABLE:
	      GC_err_puts("ATOMIC UNCOLLECTABLE");
	      break;
#	  endif
	  case STUBBORN:
	    GC_err_puts("STUBBORN");
	    break;
	  default:
	    GC_err_printf2("kind %ld, descr 0x%lx", kind, hhdr -> hb_descr);
	}
    }
}

    

void GC_print_obj(p)
ptr_t p;
{
    register oh * ohdr = (oh *)GC_base(p);
    
    GC_ASSERT(!I_HOLD_LOCK());
    GC_err_printf1("0x%lx (", ((unsigned long)ohdr + sizeof(oh)));
    GC_err_puts(ohdr -> oh_string);
#   ifdef SHORT_DBG_HDRS
      GC_err_printf1(":%ld, ", (unsigned long)(ohdr -> oh_int));
#   else
      GC_err_printf2(":%ld, sz=%ld, ", (unsigned long)(ohdr -> oh_int),
          			        (unsigned long)(ohdr -> oh_sz));
#   endif
    GC_print_type((ptr_t)(ohdr + 1));
    GC_err_puts(")\n");
    PRINT_CALL_CHAIN(ohdr);
}

# if defined(__STDC__) || defined(__cplusplus)
    void GC_debug_print_heap_obj_proc(ptr_t p)
# else
    void GC_debug_print_heap_obj_proc(p)
    ptr_t p;
# endif
{
    GC_ASSERT(!I_HOLD_LOCK());
    if (GC_HAS_DEBUG_INFO(p)) {
	GC_print_obj(p);
    } else {
	GC_default_print_heap_obj_proc(p);
    }
}

#ifndef SHORT_DBG_HDRS
void GC_print_smashed_obj(p, clobbered_addr)
ptr_t p, clobbered_addr;
{
    register oh * ohdr = (oh *)GC_base(p);
    
    GC_ASSERT(!I_HOLD_LOCK());
    GC_err_printf2("0x%lx in object at 0x%lx(", (unsigned long)clobbered_addr,
    					        (unsigned long)p);
    if (clobbered_addr <= (ptr_t)(&(ohdr -> oh_sz))
        || ohdr -> oh_string == 0) {
        GC_err_printf1("<smashed>, appr. sz = %ld)\n",
        	       (GC_size((ptr_t)ohdr) - DEBUG_BYTES));
    } else {
        if (ohdr -> oh_string[0] == '\0') {
            GC_err_puts("EMPTY(smashed?)");
        } else {
            GC_err_puts(ohdr -> oh_string);
        }
        GC_err_printf2(":%ld, sz=%ld)\n", (unsigned long)(ohdr -> oh_int),
        			          (unsigned long)(ohdr -> oh_sz));
        PRINT_CALL_CHAIN(ohdr);
    }
}
#endif

void GC_check_heap_proc GC_PROTO((void));

void GC_print_all_smashed_proc GC_PROTO((void));

void GC_do_nothing() {}

void GC_start_debugging()
{
#   ifndef SHORT_DBG_HDRS
      GC_check_heap = GC_check_heap_proc;
      GC_print_all_smashed = GC_print_all_smashed_proc;
#   else
      GC_check_heap = GC_do_nothing;
      GC_print_all_smashed = GC_do_nothing;
#   endif
    GC_print_heap_obj = GC_debug_print_heap_obj_proc;
    GC_debugging_started = TRUE;
    GC_register_displacement((word)sizeof(oh));
}

size_t GC_debug_header_size = sizeof(oh);

# if defined(__STDC__) || defined(__cplusplus)
    void GC_debug_register_displacement(GC_word offset)
# else
    void GC_debug_register_displacement(offset) 
    GC_word offset;
# endif
{
    GC_register_displacement(offset);
    GC_register_displacement((word)sizeof(oh) + offset);
}

# ifdef __STDC__
    GC_PTR GC_debug_malloc(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc(lb, s, i)
    size_t lb;
    char * s;
    int i;
#   ifdef GC_ADD_CALLER
	--> GC_ADD_CALLER not implemented for K&R C
#   endif
# endif
{
    GC_PTR result = GC_malloc(lb + DEBUG_BYTES);
    
    if (result == 0) {
        GC_err_printf1("GC_debug_malloc(%ld) returning NIL (",
        	       (unsigned long) lb);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(0);
    }
    if (!GC_debugging_started) {
    	GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

# ifdef __STDC__
    GC_PTR GC_debug_malloc_ignore_off_page(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc_ignore_off_page(lb, s, i)
    size_t lb;
    char * s;
    int i;
#   ifdef GC_ADD_CALLER
	--> GC_ADD_CALLER not implemented for K&R C
#   endif
# endif
{
    GC_PTR result = GC_malloc_ignore_off_page(lb + DEBUG_BYTES);
    
    if (result == 0) {
        GC_err_printf1("GC_debug_malloc_ignore_off_page(%ld) returning NIL (",
        	       (unsigned long) lb);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(0);
    }
    if (!GC_debugging_started) {
    	GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

# ifdef __STDC__
    GC_PTR GC_debug_malloc_atomic_ignore_off_page(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc_atomic_ignore_off_page(lb, s, i)
    size_t lb;
    char * s;
    int i;
#   ifdef GC_ADD_CALLER
	--> GC_ADD_CALLER not implemented for K&R C
#   endif
# endif
{
    GC_PTR result = GC_malloc_atomic_ignore_off_page(lb + DEBUG_BYTES);
    
    if (result == 0) {
        GC_err_printf1("GC_debug_malloc_atomic_ignore_off_page(%ld)"
		       " returning NIL (", (unsigned long) lb);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(0);
    }
    if (!GC_debugging_started) {
    	GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

# ifdef DBG_HDRS_ALL
/* 
 * An allocation function for internal use.
 * Normally internally allocated objects do not have debug information.
 * But in this case, we need to make sure that all objects have debug
 * headers.
 * We assume debugging was started in collector initialization,
 * and we already hold the GC lock.
 */
  GC_PTR GC_debug_generic_malloc_inner(size_t lb, int k)
  {
    GC_PTR result = GC_generic_malloc_inner(lb + DEBUG_BYTES, k);
    
    if (result == 0) {
        GC_err_printf1("GC internal allocation (%ld bytes) returning NIL\n",
        	       (unsigned long) lb);
        return(0);
    }
    ADD_CALL_CHAIN(result, GC_RETURN_ADDR);
    return (GC_store_debug_info_inner(result, (word)lb, "INTERNAL", (word)0));
  }

  GC_PTR GC_debug_generic_malloc_inner_ignore_off_page(size_t lb, int k)
  {
    GC_PTR result = GC_generic_malloc_inner_ignore_off_page(
					        lb + DEBUG_BYTES, k);
    
    if (result == 0) {
        GC_err_printf1("GC internal allocation (%ld bytes) returning NIL\n",
        	       (unsigned long) lb);
        return(0);
    }
    ADD_CALL_CHAIN(result, GC_RETURN_ADDR);
    return (GC_store_debug_info_inner(result, (word)lb, "INTERNAL", (word)0));
  }
# endif

#ifdef STUBBORN_ALLOC
# ifdef __STDC__
    GC_PTR GC_debug_malloc_stubborn(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc_stubborn(lb, s, i)
    size_t lb;
    char * s;
    int i;
# endif
{
    GC_PTR result = GC_malloc_stubborn(lb + DEBUG_BYTES);
    
    if (result == 0) {
        GC_err_printf1("GC_debug_malloc(%ld) returning NIL (",
        	       (unsigned long) lb);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(0);
    }
    if (!GC_debugging_started) {
    	GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

void GC_debug_change_stubborn(p)
GC_PTR p;
{
    register GC_PTR q = GC_base(p);
    register hdr * hhdr;
    
    if (q == 0) {
        GC_err_printf1("Bad argument: 0x%lx to GC_debug_change_stubborn\n",
        	       (unsigned long) p);
        ABORT("GC_debug_change_stubborn: bad arg");
    }
    hhdr = HDR(q);
    if (hhdr -> hb_obj_kind != STUBBORN) {
        GC_err_printf1("GC_debug_change_stubborn arg not stubborn: 0x%lx\n",
        	       (unsigned long) p);
        ABORT("GC_debug_change_stubborn: arg not stubborn");
    }
    GC_change_stubborn(q);
}

void GC_debug_end_stubborn_change(p)
GC_PTR p;
{
    register GC_PTR q = GC_base(p);
    register hdr * hhdr;
    
    if (q == 0) {
        GC_err_printf1("Bad argument: 0x%lx to GC_debug_end_stubborn_change\n",
        	       (unsigned long) p);
        ABORT("GC_debug_end_stubborn_change: bad arg");
    }
    hhdr = HDR(q);
    if (hhdr -> hb_obj_kind != STUBBORN) {
        GC_err_printf1("debug_end_stubborn_change arg not stubborn: 0x%lx\n",
        	       (unsigned long) p);
        ABORT("GC_debug_end_stubborn_change: arg not stubborn");
    }
    GC_end_stubborn_change(q);
}

#else /* !STUBBORN_ALLOC */

# ifdef __STDC__
    GC_PTR GC_debug_malloc_stubborn(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc_stubborn(lb, s, i)
    size_t lb;
    char * s;
    int i;
# endif
{
    return GC_debug_malloc(lb, OPT_RA s, i);
}

void GC_debug_change_stubborn(p)
GC_PTR p;
{
}

void GC_debug_end_stubborn_change(p)
GC_PTR p;
{
}

#endif /* !STUBBORN_ALLOC */

# ifdef __STDC__
    GC_PTR GC_debug_malloc_atomic(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc_atomic(lb, s, i)
    size_t lb;
    char * s;
    int i;
# endif
{
    GC_PTR result = GC_malloc_atomic(lb + DEBUG_BYTES);
    
    if (result == 0) {
        GC_err_printf1("GC_debug_malloc_atomic(%ld) returning NIL (",
        	      (unsigned long) lb);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(0);
    }
    if (!GC_debugging_started) {
        GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

# ifdef __STDC__
    GC_PTR GC_debug_malloc_uncollectable(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc_uncollectable(lb, s, i)
    size_t lb;
    char * s;
    int i;
# endif
{
    GC_PTR result = GC_malloc_uncollectable(lb + UNCOLLECTABLE_DEBUG_BYTES);
    
    if (result == 0) {
        GC_err_printf1("GC_debug_malloc_uncollectable(%ld) returning NIL (",
        	      (unsigned long) lb);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(0);
    }
    if (!GC_debugging_started) {
        GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

#ifdef ATOMIC_UNCOLLECTABLE
# ifdef __STDC__
    GC_PTR GC_debug_malloc_atomic_uncollectable(size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_malloc_atomic_uncollectable(lb, s, i)
    size_t lb;
    char * s;
    int i;
# endif
{
    GC_PTR result =
	GC_malloc_atomic_uncollectable(lb + UNCOLLECTABLE_DEBUG_BYTES);
    
    if (result == 0) {
        GC_err_printf1(
		"GC_debug_malloc_atomic_uncollectable(%ld) returning NIL (",
                (unsigned long) lb);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(0);
    }
    if (!GC_debugging_started) {
        GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}
#endif /* ATOMIC_UNCOLLECTABLE */

# ifdef __STDC__
    void GC_debug_free(GC_PTR p)
# else
    void GC_debug_free(p)
    GC_PTR p;
# endif
{
    register GC_PTR base;
    register ptr_t clobbered;
    
    if (0 == p) return;
    base = GC_base(p);
    if (base == 0) {
        GC_err_printf1("Attempt to free invalid pointer %lx\n",
        	       (unsigned long)p);
        ABORT("free(invalid pointer)");
    }
    if ((ptr_t)p - (ptr_t)base != sizeof(oh)) {
        GC_err_printf1(
        	  "GC_debug_free called on pointer %lx wo debugging info\n",
        	  (unsigned long)p);
    } else {
#     ifndef SHORT_DBG_HDRS
        clobbered = GC_check_annotated_obj((oh *)base);
        if (clobbered != 0) {
          if (((oh *)base) -> oh_sz == GC_size(base)) {
            GC_err_printf0(
                  "GC_debug_free: found previously deallocated (?) object at ");
          } else {
            GC_err_printf0("GC_debug_free: found smashed location at ");
          }
          GC_print_smashed_obj(p, clobbered);
        }
        /* Invalidate size */
        ((oh *)base) -> oh_sz = GC_size(base);
#     endif /* SHORT_DBG_HDRS */
    }
    if (GC_find_leak) {
        GC_free(base);
    } else {
	register hdr * hhdr = HDR(p);
	GC_bool uncollectable = FALSE;

        if (hhdr ->  hb_obj_kind == UNCOLLECTABLE) {
	    uncollectable = TRUE;
	}
#	ifdef ATOMIC_UNCOLLECTABLE
	    if (hhdr ->  hb_obj_kind == AUNCOLLECTABLE) {
		    uncollectable = TRUE;
	    }
#	endif
	if (uncollectable) {
	    GC_free(base);
	} else {
	    size_t i;
	    size_t obj_sz = hhdr -> hb_sz - BYTES_TO_WORDS(sizeof(oh));

	    for (i = 0; i < obj_sz; ++i) ((word *)p)[i] = 0xdeadbeef;
	    GC_ASSERT((word *)p + i == (word *)base + hhdr -> hb_sz);
	}
    } /* !GC_find_leak */
}

#ifdef THREADS

extern void GC_free_inner(GC_PTR p);

/* Used internally; we assume it's called correctly.	*/
void GC_debug_free_inner(GC_PTR p)
{
    GC_free_inner(GC_base(p));
}
#endif

# ifdef __STDC__
    GC_PTR GC_debug_realloc(GC_PTR p, size_t lb, GC_EXTRA_PARAMS)
# else
    GC_PTR GC_debug_realloc(p, lb, s, i)
    GC_PTR p;
    size_t lb;
    char *s;
    int i;
# endif
{
    register GC_PTR base = GC_base(p);
    register ptr_t clobbered;
    register GC_PTR result;
    register size_t copy_sz = lb;
    register size_t old_sz;
    register hdr * hhdr;
    
    if (p == 0) return(GC_debug_malloc(lb, OPT_RA s, i));
    if (base == 0) {
        GC_err_printf1(
              "Attempt to reallocate invalid pointer %lx\n", (unsigned long)p);
        ABORT("realloc(invalid pointer)");
    }
    if ((ptr_t)p - (ptr_t)base != sizeof(oh)) {
        GC_err_printf1(
        	"GC_debug_realloc called on pointer %lx wo debugging info\n",
        	(unsigned long)p);
        return(GC_realloc(p, lb));
    }
    hhdr = HDR(base);
    switch (hhdr -> hb_obj_kind) {
#    ifdef STUBBORN_ALLOC
      case STUBBORN:
        result = GC_debug_malloc_stubborn(lb, OPT_RA s, i);
        break;
#    endif
      case NORMAL:
        result = GC_debug_malloc(lb, OPT_RA s, i);
        break;
      case PTRFREE:
        result = GC_debug_malloc_atomic(lb, OPT_RA s, i);
        break;
      case UNCOLLECTABLE:
	result = GC_debug_malloc_uncollectable(lb, OPT_RA s, i);
 	break;
#    ifdef ATOMIC_UNCOLLECTABLE
      case AUNCOLLECTABLE:
	result = GC_debug_malloc_atomic_uncollectable(lb, OPT_RA s, i);
	break;
#    endif
      default:
        GC_err_printf0("GC_debug_realloc: encountered bad kind\n");
        ABORT("bad kind");
    }
#   ifdef SHORT_DBG_HDRS
      old_sz = GC_size(base) - sizeof(oh);
#   else
      clobbered = GC_check_annotated_obj((oh *)base);
      if (clobbered != 0) {
        GC_err_printf0("GC_debug_realloc: found smashed location at ");
        GC_print_smashed_obj(p, clobbered);
      }
      old_sz = ((oh *)base) -> oh_sz;
#   endif
    if (old_sz < copy_sz) copy_sz = old_sz;
    if (result == 0) return(0);
    BCOPY(p, result,  copy_sz);
    GC_debug_free(p);
    return(result);
}

#ifndef SHORT_DBG_HDRS

/* List of smashed objects.  We defer printing these, since we can't	*/
/* always print them nicely with the allocation lock held.		*/
/* We put them here instead of in GC_arrays, since it may be useful to	*/
/* be able to look at them with the debugger.				*/
#define MAX_SMASHED 20
ptr_t GC_smashed[MAX_SMASHED];
unsigned GC_n_smashed = 0;

# if defined(__STDC__) || defined(__cplusplus)
    void GC_add_smashed(ptr_t smashed)
# else
    void GC_add_smashed(smashed)
    ptr_t smashed;
#endif
{
    GC_ASSERT(GC_is_marked(GC_base(smashed)));
    GC_smashed[GC_n_smashed] = smashed;
    if (GC_n_smashed < MAX_SMASHED - 1) ++GC_n_smashed;
      /* In case of overflow, we keep the first MAX_SMASHED-1	*/
      /* entries plus the last one.				*/
    GC_have_errors = TRUE;
}

/* Print all objects on the list.  Clear the list.	*/
void GC_print_all_smashed_proc ()
{
    unsigned i;

    GC_ASSERT(!I_HOLD_LOCK());
    if (GC_n_smashed == 0) return;
    GC_err_printf0("GC_check_heap_block: found smashed heap objects:\n");
    for (i = 0; i < GC_n_smashed; ++i) {
        GC_print_smashed_obj(GC_base(GC_smashed[i]), GC_smashed[i]);
	GC_smashed[i] = 0;
    }
    GC_n_smashed = 0;
}

/* Check all marked objects in the given block for validity */
/*ARGSUSED*/
# if defined(__STDC__) || defined(__cplusplus)
    void GC_check_heap_block(register struct hblk *hbp, word dummy)
# else
    void GC_check_heap_block(hbp, dummy)
    register struct hblk *hbp;	/* ptr to current heap block		*/
    word dummy;
# endif
{
    register struct hblkhdr * hhdr = HDR(hbp);
    register word sz = hhdr -> hb_sz;
    register int word_no;
    register word *p, *plim;
    
    p = (word *)(hbp->hb_body);
    word_no = 0;
    if (sz > MAXOBJSZ) {
	plim = p;
    } else {
    	plim = (word *)((((word)hbp) + HBLKSIZE) - WORDS_TO_BYTES(sz));
    }
    /* go through all words in block */
	while( p <= plim ) {
	    if( mark_bit_from_hdr(hhdr, word_no)
	        && GC_HAS_DEBUG_INFO((ptr_t)p)) {
	        ptr_t clobbered = GC_check_annotated_obj((oh *)p);
	        
	        if (clobbered != 0) GC_add_smashed(clobbered);
	    }
	    word_no += sz;
	    p += sz;
	}
}


/* This assumes that all accessible objects are marked, and that	*/
/* I hold the allocation lock.	Normally called by collector.		*/
void GC_check_heap_proc()
{
#   ifndef SMALL_CONFIG
#     ifdef ALIGN_DOUBLE
        GC_STATIC_ASSERT((sizeof(oh) & (2 * sizeof(word) - 1)) == 0);
#     else
        GC_STATIC_ASSERT((sizeof(oh) & (sizeof(word) - 1)) == 0);