remove gc

1 files changed, 0 insertions, 1690 deletions

diff --git a/gc/mark.c b/gc/mark.c
deleted file mode 100644
index 993c8d6..0000000
--- a/gc/mark.c
+++ /dev/null
@@ -1,1690 +0,0 @@
-
-/*
- * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
- * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
- * Copyright (c) 2000 by Hewlett-Packard Company.  All rights reserved.
- *
- * 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 <stdio.h>
-# include "private/gc_pmark.h"
-
-/* We put this here to minimize the risk of inlining. */
-/*VARARGS*/
-#ifdef __WATCOMC__
-  void GC_noop(void *p, ...) {}
-#else
-  void GC_noop() {}
-#endif
-
-/* Single argument version, robust against whole program analysis. */
-void GC_noop1(x)
-word x;
-{
-    static VOLATILE word sink;
-
-    sink = x;
-}
-
-/* mark_proc GC_mark_procs[MAX_MARK_PROCS] = {0} -- declared in gc_priv.h */
-
-word GC_n_mark_procs = GC_RESERVED_MARK_PROCS;
-
-/* Initialize GC_obj_kinds properly and standard free lists properly.  	*/
-/* This must be done statically since they may be accessed before 	*/
-/* GC_init is called.							*/
-/* It's done here, since we need to deal with mark descriptors.		*/
-struct obj_kind GC_obj_kinds[MAXOBJKINDS] = {
-/* PTRFREE */ { &GC_aobjfreelist[0], 0 /* filled in dynamically */,
-		0 | GC_DS_LENGTH, FALSE, FALSE },
-/* NORMAL  */ { &GC_objfreelist[0], 0,
-		0 | GC_DS_LENGTH,  /* Adjusted in GC_init_inner for EXTRA_BYTES */
-		TRUE /* add length to descr */, TRUE },
-/* UNCOLLECTABLE */
-	      { &GC_uobjfreelist[0], 0,
-		0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
-# ifdef ATOMIC_UNCOLLECTABLE
-   /* AUNCOLLECTABLE */
-	      { &GC_auobjfreelist[0], 0,
-		0 | GC_DS_LENGTH, FALSE /* add length to descr */, FALSE },
-# endif
-# ifdef STUBBORN_ALLOC
-/*STUBBORN*/ { &GC_sobjfreelist[0], 0,
-		0 | GC_DS_LENGTH, TRUE /* add length to descr */, TRUE },
-# endif
-};
-
-# ifdef ATOMIC_UNCOLLECTABLE
-#   ifdef STUBBORN_ALLOC
-      int GC_n_kinds = 5;
-#   else
-      int GC_n_kinds = 4;
-#   endif
-# else
-#   ifdef STUBBORN_ALLOC
-      int GC_n_kinds = 4;
-#   else
-      int GC_n_kinds = 3;
-#   endif
-# endif
-
-
-# ifndef INITIAL_MARK_STACK_SIZE
-#   define INITIAL_MARK_STACK_SIZE (1*HBLKSIZE)
-		/* INITIAL_MARK_STACK_SIZE * sizeof(mse) should be a 	*/
-		/* multiple of HBLKSIZE.				*/
-		/* The incremental collector actually likes a larger	*/
-		/* size, since it want to push all marked dirty objs	*/
-		/* before marking anything new.  Currently we let it	*/
-		/* grow dynamically.					*/
-# endif
-
-/*
- * Limits of stack for GC_mark routine.
- * All ranges between GC_mark_stack(incl.) and GC_mark_stack_top(incl.) still
- * need to be marked from.
- */
-
-word GC_n_rescuing_pages;	/* Number of dirty pages we marked from */
-				/* excludes ptrfree pages, etc.		*/
-
-mse * GC_mark_stack;
-
-mse * GC_mark_stack_limit;
-
-word GC_mark_stack_size = 0;
- 
-#ifdef PARALLEL_MARK
-  mse * VOLATILE GC_mark_stack_top;
-#else
-  mse * GC_mark_stack_top;
-#endif
-
-static struct hblk * scan_ptr;
-
-mark_state_t GC_mark_state = MS_NONE;
-
-GC_bool GC_mark_stack_too_small = FALSE;
-
-GC_bool GC_objects_are_marked = FALSE;	/* Are there collectable marked	*/
-					/* objects in the heap?		*/
-
-/* Is a collection in progress?  Note that this can return true in the	*/
-/* nonincremental case, if a collection has been abandoned and the	*/
-/* mark state is now MS_INVALID.					*/
-GC_bool GC_collection_in_progress()
-{
-    return(GC_mark_state != MS_NONE);
-}
-
-/* clear all mark bits in the header */
-void GC_clear_hdr_marks(hhdr)
-register hdr * hhdr;
-{
-#   ifdef USE_MARK_BYTES
-      BZERO(hhdr -> hb_marks, MARK_BITS_SZ);
-#   else
-      BZERO(hhdr -> hb_marks, MARK_BITS_SZ*sizeof(word));
-#   endif
-}
-
-/* Set all mark bits in the header.  Used for uncollectable blocks. */
-void GC_set_hdr_marks(hhdr)
-register hdr * hhdr;
-{
-    register int i;
-
-    for (i = 0; i < MARK_BITS_SZ; ++i) {
-#     ifdef USE_MARK_BYTES
-    	hhdr -> hb_marks[i] = 1;
-#     else
-    	hhdr -> hb_marks[i] = ONES;
-#     endif
-    }
-}
-
-/*
- * Clear all mark bits associated with block h.
- */
-/*ARGSUSED*/
-# if defined(__STDC__) || defined(__cplusplus)
-    static void clear_marks_for_block(struct hblk *h, word dummy)
-# else
-    static void clear_marks_for_block(h, dummy)
-    struct hblk *h;
-    word dummy;
-# endif
-{
-    register hdr * hhdr = HDR(h);
-    
-    if (IS_UNCOLLECTABLE(hhdr -> hb_obj_kind)) return;
-        /* Mark bit for these is cleared only once the object is 	*/
-        /* explicitly deallocated.  This either frees the block, or	*/
-        /* the bit is cleared once the object is on the free list.	*/
-    GC_clear_hdr_marks(hhdr);
-}
-
-/* Slow but general routines for setting/clearing/asking about mark bits */
-void GC_set_mark_bit(p)
-ptr_t p;
-{
-    register struct hblk *h = HBLKPTR(p);
-    register hdr * hhdr = HDR(h);
-    register int word_no = (word *)p - (word *)h;
-    
-    set_mark_bit_from_hdr(hhdr, word_no);
-}
-
-void GC_clear_mark_bit(p)
-ptr_t p;
-{
-    register struct hblk *h = HBLKPTR(p);
-    register hdr * hhdr = HDR(h);
-    register int word_no = (word *)p - (word *)h;
-    
-    clear_mark_bit_from_hdr(hhdr, word_no);
-}
-
-GC_bool GC_is_marked(p)
-ptr_t p;
-{
-    register struct hblk *h = HBLKPTR(p);
-    register hdr * hhdr = HDR(h);
-    register int word_no = (word *)p - (word *)h;
-    
-    return(mark_bit_from_hdr(hhdr, word_no));
-}
-
-
-/*
- * Clear mark bits in all allocated heap blocks.  This invalidates
- * the marker invariant, and sets GC_mark_state to reflect this.
- * (This implicitly starts marking to reestablish the invariant.)
- */
-void GC_clear_marks()
-{
-    GC_apply_to_all_blocks(clear_marks_for_block, (word)0);
-    GC_objects_are_marked = FALSE;
-    GC_mark_state = MS_INVALID;
-    scan_ptr = 0;
-#   ifdef GATHERSTATS
-	/* Counters reflect currently marked objects: reset here */
-        GC_composite_in_use = 0;
-        GC_atomic_in_use = 0;
-#   endif
-
-}
-
-/* Initiate a garbage collection.  Initiates a full collection if the	*/
-/* mark	state is invalid.						*/
-/*ARGSUSED*/
-void GC_initiate_gc()
-{
-    if (GC_dirty_maintained) GC_read_dirty();
-#   ifdef STUBBORN_ALLOC
-    	GC_read_changed();
-#   endif
-#   ifdef CHECKSUMS
-	{
-	    extern void GC_check_dirty();
-	    
-	    if (GC_dirty_maintained) GC_check_dirty();
-	}
-#   endif
-    GC_n_rescuing_pages = 0;
-    if (GC_mark_state == MS_NONE) {
-        GC_mark_state = MS_PUSH_RESCUERS;
-    } else if (GC_mark_state != MS_INVALID) {
-    	ABORT("unexpected state");
-    } /* else this is really a full collection, and mark	*/
-      /* bits are invalid.					*/
-    scan_ptr = 0;
-}
-
-
-static void alloc_mark_stack();
-
-/* Perform a small amount of marking.			*/
-/* We try to touch roughly a page of memory.		*/
-/* Return TRUE if we just finished a mark phase.	*/
-/* Cold_gc_frame is an address inside a GC frame that	*/
-/* remains valid until all marking is complete.		*/
-/* A zero value indicates that it's OK to miss some	*/
-/* register values.					*/
-GC_bool GC_mark_some(cold_gc_frame)
-ptr_t cold_gc_frame;
-{
-#if defined(MSWIN32) && !defined(__GNUC__)
-  /* Windows 98 appears to asynchronously create and remove writable	*/
-  /* memory mappings, for reasons we haven't yet understood.  Since	*/
-  /* we look for writable regions to determine the root set, we may	*/
-  /* try to mark from an address range that disappeared since we 	*/
-  /* started the collection.  Thus we have to recover from faults here. */
-  /* This code does not appear to be necessary for Windows 95/NT/2000.	*/ 
-  /* Note that this code should never generate an incremental GC write	*/
-  /* fault.								*/
-  __try {
-#endif /* defined(MSWIN32) && !defined(__GNUC__) */
-    switch(GC_mark_state) {
-    	case MS_NONE:
-    	    return(FALSE);
-    	    
-    	case MS_PUSH_RESCUERS:
-    	    if (GC_mark_stack_top
-    	        >= GC_mark_stack_limit - INITIAL_MARK_STACK_SIZE/2) {
-		/* Go ahead and mark, even though that might cause us to */
-		/* see more marked dirty objects later on.  Avoid this	 */
-		/* in the future.					 */
-		GC_mark_stack_too_small = TRUE;
-    	        MARK_FROM_MARK_STACK();
-    	        return(FALSE);
-    	    } else {
-    	        scan_ptr = GC_push_next_marked_dirty(scan_ptr);
-    	        if (scan_ptr == 0) {
-#		    ifdef CONDPRINT
-		      if (GC_print_stats) {
-			GC_printf1("Marked from %lu dirty pages\n",
-				   (unsigned long)GC_n_rescuing_pages);
-		      }
-#		    endif
-    	    	    GC_push_roots(FALSE, cold_gc_frame);
-    	    	    GC_objects_are_marked = TRUE;
-    	    	    if (GC_mark_state != MS_INVALID) {
-    	    	        GC_mark_state = MS_ROOTS_PUSHED;
-    	    	    }
-    	    	}
-    	    }
-    	    return(FALSE);
-    	
-    	case MS_PUSH_UNCOLLECTABLE:
-    	    if (GC_mark_stack_top
-    	        >= GC_mark_stack + GC_mark_stack_size/4) {
-#		ifdef PARALLEL_MARK
-		  /* Avoid this, since we don't parallelize the marker	*/
-		  /* here.						*/
-		  if (GC_parallel) GC_mark_stack_too_small = TRUE;
-#		endif
-    	        MARK_FROM_MARK_STACK();
-    	        return(FALSE);
-    	    } else {
-    	        scan_ptr = GC_push_next_marked_uncollectable(scan_ptr);
-    	        if (scan_ptr == 0) {
-    	    	    GC_push_roots(TRUE, cold_gc_frame);
-    	    	    GC_objects_are_marked = TRUE;
-    	    	    if (GC_mark_state != MS_INVALID) {
-    	    	        GC_mark_state = MS_ROOTS_PUSHED;
-    	    	    }
-    	    	}
-    	    }
-    	    return(FALSE);
-    	
-    	case MS_ROOTS_PUSHED:
-#	    ifdef PARALLEL_MARK
-	      /* In the incremental GC case, this currently doesn't	*/
-	      /* quite do the right thing, since it runs to		*/
-	      /* completion.  On the other hand, starting a		*/
-	      /* parallel marker is expensive, so perhaps it is		*/
-	      /* the right thing?					*/
-	      /* Eventually, incremental marking should run		*/
-	      /* asynchronously in multiple threads, without grabbing	*/
-	      /* the allocation lock.					*/
-	        if (GC_parallel) {
-		  GC_do_parallel_mark();
-		  GC_ASSERT(GC_mark_stack_top < GC_first_nonempty);
-		  GC_mark_stack_top = GC_mark_stack - 1;
-    	          if (GC_mark_stack_too_small) {
-    	            alloc_mark_stack(2*GC_mark_stack_size);
-    	          }
-		  if (GC_mark_state == MS_ROOTS_PUSHED) {
-    	            GC_mark_state = MS_NONE;
-    	            return(TRUE);
-		  } else {
-		    return(FALSE);
-	          }
-		}
-#	    endif
-    	    if (GC_mark_stack_top >= GC_mark_stack) {
-    	        MARK_FROM_MARK_STACK();
-    	        return(FALSE);
-    	    } else {
-    	        GC_mark_state = MS_NONE;
-    	        if (GC_mark_stack_too_small) {
-    	            alloc_mark_stack(2*GC_mark_stack_size);
-    	        }
-    	        return(TRUE);
-    	    }
-    	    
-    	case MS_INVALID:
-    	case MS_PARTIALLY_INVALID:
-	    if (!GC_objects_are_marked) {
-		GC_mark_state = MS_PUSH_UNCOLLECTABLE;
-		return(FALSE);
-	    }
-    	    if (GC_mark_stack_top >= GC_mark_stack) {
-    	        MARK_FROM_MARK_STACK();
-    	        return(FALSE);
-    	    }
-    	    if (scan_ptr == 0 && GC_mark_state == MS_INVALID) {
-		/* About to start a heap scan for marked objects. */
-		/* Mark stack is empty.  OK to reallocate.	  */
-		if (GC_mark_stack_too_small) {
-    	            alloc_mark_stack(2*GC_mark_stack_size);
-		}
-		GC_mark_state = MS_PARTIALLY_INVALID;
-    	    }
-    	    scan_ptr = GC_push_next_marked(scan_ptr);
-    	    if (scan_ptr == 0 && GC_mark_state == MS_PARTIALLY_INVALID) {
-    	    	GC_push_roots(TRUE, cold_gc_frame);
-    	    	GC_objects_are_marked = TRUE;
-    	    	if (GC_mark_state != MS_INVALID) {
-    	    	    GC_mark_state = MS_ROOTS_PUSHED;
-    	    	}
-    	    }
-    	    return(FALSE);
-    	default:
-    	    ABORT("GC_mark_some: bad state");
-    	    return(FALSE);
-    }
-#if defined(MSWIN32) && !defined(__GNUC__)
-  } __except (GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION ?
-	    EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH) {
-#   ifdef CONDPRINT
-      if (GC_print_stats) {
-	GC_printf0("Caught ACCESS_VIOLATION in marker. "
-		   "Memory mapping disappeared.\n");
-      }
-#   endif /* CONDPRINT */
-    /* We have bad roots on the stack.  Discard mark stack.  	*/
-    /* Rescan from marked objects.  Redetermine roots.		*/
-    GC_invalidate_mark_state();	
-    scan_ptr = 0;
-    return FALSE;
-  }
-#endif /* defined(MSWIN32) && !defined(__GNUC__) */
-}
-
-
-GC_bool GC_mark_stack_empty()
-{
-    return(GC_mark_stack_top < GC_mark_stack);
-}	
-
-#ifdef PROF_MARKER
-    word GC_prof_array[10];
-#   define PROF(n) GC_prof_array[n]++
-#else
-#   define PROF(n)
-#endif
-
-/* Given a pointer to someplace other than a small object page or the	*/
-/* first page of a large object, either:				*/
-/*	- return a pointer to somewhere in the first page of the large	*/
-/*	  object, if current points to a large object.			*/
-/*	  In this case *hhdr is replaced with a pointer to the header	*/
-/*	  for the large object.						*/
-/*	- just return current if it does not point to a large object.	*/
-/*ARGSUSED*/
-ptr_t GC_find_start(current, hhdr, new_hdr_p)
-register ptr_t current;
-register hdr *hhdr, **new_hdr_p;
-{
-    if (GC_all_interior_pointers) {
-	if (hhdr != 0) {
-	    register ptr_t orig = current;
-	    
-	    current = (ptr_t)HBLKPTR(current);
-	    do {
-	      current = current - HBLKSIZE*(word)hhdr;
-	      hhdr = HDR(current);
-	    } while(IS_FORWARDING_ADDR_OR_NIL(hhdr));
-	    /* current points to the start of the large object */
-	    if (hhdr -> hb_flags & IGNORE_OFF_PAGE) return(0);
-	    if ((word *)orig - (word *)current
-	         >= (ptrdiff_t)(hhdr->hb_sz)) {
-	        /* Pointer past the end of the block */
-	        return(orig);
-	    }
-	    *new_hdr_p = hhdr;
-	    return(current);
-	} else {
-	    return(current);
-        }
-    } else {
-        return(current);
-    }
-}
-
-void GC_invalidate_mark_state()
-{
-    GC_mark_state = MS_INVALID;
-    GC_mark_stack_top = GC_mark_stack-1;
-}
-
-mse * GC_signal_mark_stack_overflow(msp)
-mse * msp;
-{
-    GC_mark_state = MS_INVALID;
-    GC_mark_stack_too_small = TRUE;
-#   ifdef CONDPRINT
-      if (GC_print_stats) {
-	GC_printf1("Mark stack overflow; current size = %lu entries\n",
-	    	    GC_mark_stack_size);
-      }
-#   endif
-    return(msp - GC_MARK_STACK_DISCARDS);
-}
-
-/*
- * Mark objects pointed to by the regions described by
- * mark stack entries between GC_mark_stack and GC_mark_stack_top,
- * inclusive.  Assumes the upper limit of a mark stack entry
- * is never 0.  A mark stack entry never has size 0.
- * We try to traverse on the order of a hblk of memory before we return.
- * Caller is responsible for calling this until the mark stack is empty.
- * Note that this is the most performance critical routine in the
- * collector.  Hence it contains all sorts of ugly hacks to speed
- * things up.  In particular, we avoid procedure calls on the common
- * path, we take advantage of peculiarities of the mark descriptor
- * encoding, we optionally maintain a cache for the block address to
- * header mapping, we prefetch when an object is "grayed", etc. 
- */
-mse * GC_mark_from(mark_stack_top, mark_stack, mark_stack_limit)
-mse * mark_stack_top;
-mse * mark_stack;
-mse * mark_stack_limit;
-{
-  int credit = HBLKSIZE;	/* Remaining credit for marking work	*/
-  register word * current_p;	/* Pointer to current candidate ptr.	*/
-  register word current;	/* Candidate pointer.			*/
-  register word * limit;	/* (Incl) limit of current candidate 	*/
-  				/* range				*/
-  register word descr;
-  register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
-  register ptr_t least_ha = GC_least_plausible_heap_addr;
-  DECLARE_HDR_CACHE;
-
-# define SPLIT_RANGE_WORDS 128  /* Must be power of 2.		*/
-
-  GC_objects_are_marked = TRUE;
-  INIT_HDR_CACHE;
-# ifdef OS2 /* Use untweaked version to circumvent compiler problem */
-  while (mark_stack_top >= mark_stack && credit >= 0) {
-# else
-  while ((((ptr_t)mark_stack_top - (ptr_t)mark_stack) | credit)
-  	>= 0) {
-# endif
-    current_p = mark_stack_top -> mse_start;
-    descr = mark_stack_top -> mse_descr;
-  retry:
-    /* current_p and descr describe the current object.		*/
-    /* *mark_stack_top is vacant.				*/
-    /* The following is 0 only for small objects described by a simple	*/
-    /* length descriptor.  For many applications this is the common	*/
-    /* case, so we try to detect it quickly.				*/
-    if (descr & ((~(WORDS_TO_BYTES(SPLIT_RANGE_WORDS) - 1)) | GC_DS_TAGS)) {
-      word tag = descr & GC_DS_TAGS;
-      
-      switch(tag) {
-        case GC_DS_LENGTH:
-          /* Large length.					        */
-          /* Process part of the range to avoid pushing too much on the	*/
-          /* stack.							*/
-	  GC_ASSERT(descr < GC_greatest_plausible_heap_addr
-			    - GC_least_plausible_heap_addr);
-#	  ifdef PARALLEL_MARK
-#	    define SHARE_BYTES 2048
-	    if (descr > SHARE_BYTES && GC_parallel
-		&& mark_stack_top < mark_stack_limit - 1) {
-	      int new_size = (descr/2) & ~(sizeof(word)-1);
-	      mark_stack_top -> mse_start = current_p;
-	      mark_stack_top -> mse_descr = new_size + sizeof(word);
-					/* makes sure we handle 	*/
-					/* misaligned pointers.		*/
-	      mark_stack_top++;
-	      current_p = (word *) ((char *)current_p + new_size);
-	      descr -= new_size;
-	      goto retry;
-	    }
-#	  endif /* PARALLEL_MARK */
-          mark_stack_top -> mse_start =
-         	limit = current_p + SPLIT_RANGE_WORDS-1;
-          mark_stack_top -> mse_descr =
-          		descr - WORDS_TO_BYTES(SPLIT_RANGE_WORDS-1);
-          /* Make sure that pointers overlapping the two ranges are	*/
-          /* considered. 						*/
-          limit = (word *)((char *)limit + sizeof(word) - ALIGNMENT);
-          break;
-        case GC_DS_BITMAP:
-          mark_stack_top--;
-          descr &= ~GC_DS_TAGS;
-          credit -= WORDS_TO_BYTES(WORDSZ/2); /* guess */
-          while (descr != 0) {
-            if ((signed_word)descr < 0) {
-              current = *current_p;
-	      if ((ptr_t)current >= least_ha && (ptr_t)current < greatest_ha) {
-		PREFETCH(current);
-                HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
-			      mark_stack_limit, current_p, exit1);
-	      }
-            }
-	    descr <<= 1;
-	    ++ current_p;
-          }
-          continue;
-        case GC_DS_PROC:
-          mark_stack_top--;
-          credit -= GC_PROC_BYTES;
-          mark_stack_top =
-              (*PROC(descr))
-              	    (current_p, mark_stack_top,
-              	    mark_stack_limit, ENV(descr));
-          continue;
-        case GC_DS_PER_OBJECT:
-	  if ((signed_word)descr >= 0) {
-	    /* Descriptor is in the object.	*/
-            descr = *(word *)((ptr_t)current_p + descr - GC_DS_PER_OBJECT);
-	  } else {
-	    /* Descriptor is in type descriptor pointed to by first	*/
-	    /* word in object.						*/
-	    ptr_t type_descr = *(ptr_t *)current_p;
-	    /* type_descr is either a valid pointer to the descriptor	*/
-	    /* structure, or this object was on a free list.  If it 	*/
-	    /* it was anything but the last object on the free list,	*/
-	    /* we will misinterpret the next object on the free list as */
-	    /* the type descriptor, and get a 0 GC descriptor, which	*/
-	    /* is ideal.  Unfortunately, we need to check for the last	*/
-	    /* object case explicitly.					*/
-	    if (0 == type_descr) {
-		/* Rarely executed.	*/
-		mark_stack_top--;
-		continue;
-	    }
-            descr = *(word *)(type_descr
-			      - (descr - (GC_DS_PER_OBJECT
-					  - GC_INDIR_PER_OBJ_BIAS)));
-	  }
-	  if (0 == descr) {
-	      /* Can happen either because we generated a 0 descriptor	*/
-	      /* or we saw a pointer to a free object.			*/
-	      mark_stack_top--;
-	      continue;
-	  }
-          goto retry;
-      }
-    } else /* Small object with length descriptor */ {
-      mark_stack_top--;
-      limit = (word *)(((ptr_t)current_p) + (word)descr);
-    }
-    /* The simple case in which we're scanning a range.	*/
-    GC_ASSERT(!((word)current_p & (ALIGNMENT-1)));
-    credit -= (ptr_t)limit - (ptr_t)current_p;
-    limit -= 1;
-    {
-#     define PREF_DIST 4
-
-#     ifndef SMALL_CONFIG
-        word deferred;
-
-	/* Try to prefetch the next pointer to be examined asap.	*/
-	/* Empirically, this also seems to help slightly without	*/
-	/* prefetches, at least on linux/X86.  Presumably this loop 	*/
-	/* ends up with less register pressure, and gcc thus ends up 	*/
-	/* generating slightly better code.  Overall gcc code quality	*/
-	/* for this loop is still not great.				*/
-	for(;;) {
-	  PREFETCH((ptr_t)limit - PREF_DIST*CACHE_LINE_SIZE);
-	  GC_ASSERT(limit >= current_p);
-	  deferred = *limit;
-	  limit = (word *)((char *)limit - ALIGNMENT);
-	  if ((ptr_t)deferred >= least_ha && (ptr_t)deferred <  greatest_ha) {
-	    PREFETCH(deferred);
-	    break;
-	  }
-	  if (current_p > limit) goto next_object;
-	  /* Unroll once, so we don't do too many of the prefetches 	*/
-	  /* based on limit.						*/
-	  deferred = *limit;
-	  limit = (word *)((char *)limit - ALIGNMENT);
-	  if ((ptr_t)deferred >= least_ha && (ptr_t)deferred <  greatest_ha) {
-	    PREFETCH(deferred);
-	    break;
-	  }
-	  if (current_p > limit) goto next_object;
-	}
-#     endif
-
-      while (current_p <= limit) {
-	/* Empirically, unrolling this loop doesn't help a lot.	*/
-	/* Since HC_PUSH_CONTENTS expands to a lot of code,	*/
-	/* we don't.						*/
-        current = *current_p;
-        PREFETCH((ptr_t)current_p + PREF_DIST*CACHE_LINE_SIZE);
-        if ((ptr_t)current >= least_ha && (ptr_t)current <  greatest_ha) {
-  	  /* Prefetch the contents of the object we just pushed.  It's	*/
-  	  /* likely we will need them soon.				*/
-  	  PREFETCH(current);
-          HC_PUSH_CONTENTS((ptr_t)current, mark_stack_top,
-  		           mark_stack_limit, current_p, exit2);
-        }
-        current_p = (word *)((char *)current_p + ALIGNMENT);
-      }
-
-#     ifndef SMALL_CONFIG
-	/* We still need to mark the entry we previously prefetched.	*/
-	/* We alrady know that it passes the preliminary pointer	*/
-	/* validity test.						*/
-        HC_PUSH_CONTENTS((ptr_t)deferred, mark_stack_top,
-  		         mark_stack_limit, current_p, exit4);
-	next_object:;
-#     endif
-    }
-  }
-  return mark_stack_top;
-}
-
-#ifdef PARALLEL_MARK
-
-/* We assume we have an ANSI C Compiler.	*/
-GC_bool GC_help_wanted = FALSE;
-unsigned GC_helper_count = 0;
-unsigned GC_active_count = 0;
-mse * VOLATILE GC_first_nonempty;
-word GC_mark_no = 0;
-
-#define LOCAL_MARK_STACK_SIZE HBLKSIZE
-	/* Under normal circumstances, this is big enough to guarantee	*/
-	/* We don't overflow half of it in a single call to 		*/
-	/* GC_mark_from.						*/
-
-
-/* Steal mark stack entries starting at mse low into mark stack local	*/
-/* until we either steal mse high, or we have max entries.		*/
-/* Return a pointer to the top of the local mark stack.		        */
-/* *next is replaced by a pointer to the next unscanned mark stack	*/
-/* entry.								*/
-mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
-			  unsigned max, mse **next)
-{
-    mse *p;
-    mse *top = local - 1;
-    unsigned i = 0;
-
-    GC_ASSERT(high >= low-1 && high - low + 1 <= GC_mark_stack_size);
-    for (p = low; p <= high && i <= max; ++p) {
-	word descr = *(volatile word *) &(p -> mse_descr);
-	if (descr != 0) {
-	    *(volatile word *) &(p -> mse_descr) = 0;
-	    ++top;
-	    top -> mse_descr = descr;
-	    top -> mse_start = p -> mse_start;
-	    GC_ASSERT(  top -> mse_descr & GC_DS_TAGS != GC_DS_LENGTH || 
-			top -> mse_descr < GC_greatest_plausible_heap_addr
-			                   - GC_least_plausible_heap_addr);
-	    /* There is no synchronization here.  We assume that at	*/
-	    /* least one thread will see the original descriptor.	*/
-	    /* Otherwise we need a barrier.				*/
-	    /* More than one thread may get this entry, but that's only */
-	    /* a minor performance problem.				*/
-	    /* If this is a big object, count it as			*/
-	    /* size/256 + 1 objects.					*/
-	    ++i;
-	    if ((descr & GC_DS_TAGS) == GC_DS_LENGTH) i += (descr >> 8);
-	}
-    }
-    *next = p;
-    return top;
-}
-
-/* Copy back a local mark stack.	*/
-/* low and high are inclusive bounds.	*/
-void GC_return_mark_stack(mse * low, mse * high)
-{
-    mse * my_top;
-    mse * my_start;
-    size_t stack_size;
-
-    if (high < low) return;
-    stack_size = high - low + 1;
-    GC_acquire_mark_lock();
-    my_top = GC_mark_stack_top;
-    my_start = my_top + 1;
-    if (my_start - GC_mark_stack + stack_size > GC_mark_stack_size) {
-#     ifdef CONDPRINT
-	if (GC_print_stats) {
-	  GC_printf0("No room to copy back mark stack.");
-	}
-#     endif
-      GC_mark_state = MS_INVALID;
-      GC_mark_stack_too_small = TRUE;
-      /* We drop the local mark stack.  We'll fix things later.	*/
-    } else {
-      BCOPY(low, my_start, stack_size * sizeof(mse));
-      GC_ASSERT(GC_mark_stack_top = my_top);
-#     if !defined(IA64) && !defined(HP_PA)
-        GC_memory_write_barrier();
-#     endif
-	/* On IA64, the volatile write acts as a release barrier. */
-      GC_mark_stack_top = my_top + stack_size;
-    }
-    GC_release_mark_lock();
-    GC_notify_all_marker();
-}
-
-/* Mark from the local mark stack.		*/
-/* On return, the local mark stack is empty.	*/
-/* But this may be achieved by copying the	*/
-/* local mark stack back into the global one.	*/
-void GC_do_local_mark(mse *local_mark_stack, mse *local_top)
-{
-    unsigned n;
-#   define N_LOCAL_ITERS 1
-
-#   ifdef GC_ASSERTIONS
-      /* Make sure we don't hold mark lock. */
-	GC_acquire_mark_lock();
-	GC_release_mark_lock();
-#   endif
-    for (;;) {
-        for (n = 0; n < N_LOCAL_ITERS; ++n) {
-	    local_top = GC_mark_from(local_top, local_mark_stack,
-				     local_mark_stack + LOCAL_MARK_STACK_SIZE);
-	    if (local_top < local_mark_stack) return;
-	    if (local_top - local_mark_stack >= LOCAL_MARK_STACK_SIZE/2) {
-	 	GC_return_mark_stack(local_mark_stack, local_top);
-		return;
-	    }
-	}
-	if (GC_mark_stack_top < GC_first_nonempty &&
-	    GC_active_count < GC_helper_count
-	    && local_top > local_mark_stack + 1) {
-	    /* Try to share the load, since the main stack is empty,	*/
-	    /* and helper threads are waiting for a refill.		*/
-	    /* The entries near the bottom of the stack are likely	*/
-	    /* to require more work.  Thus we return those, eventhough	*/
-	    /* it's harder.						*/
-	    mse * p;
- 	    mse * new_bottom = local_mark_stack
-				+ (local_top - local_mark_stack)/2;
-	    GC_ASSERT(new_bottom > local_mark_stack
-		      && new_bottom < local_top);
-	    GC_return_mark_stack(local_mark_stack, new_bottom - 1);
-	    memmove(local_mark_stack, new_bottom,
-		    (local_top - new_bottom + 1) * sizeof(mse));
-	    local_top -= (new_bottom - local_mark_stack);
-	}
-    }
-}
-
-#define ENTRIES_TO_GET 5
-
-long GC_markers = 2;		/* Normally changed by thread-library-	*/
-				/* -specific code.			*/
-
-/* Mark using the local mark stack until the global mark stack is empty	*/
-/* and there are no active workers. Update GC_first_nonempty to reflect	*/
-/* progress.								*/
-/* Caller does not hold mark lock.					*/
-/* Caller has already incremented GC_helper_count.  We decrement it,	*/
-/* and maintain GC_active_count.					*/
-void GC_mark_local(mse *local_mark_stack, int id)
-{
-    mse * my_first_nonempty;
-
-    GC_acquire_mark_lock();
-    GC_active_count++;
-    my_first_nonempty = GC_first_nonempty;
-    GC_ASSERT(GC_first_nonempty >= GC_mark_stack && 
-	      GC_first_nonempty <= GC_mark_stack_top + 1);
-#   ifdef PRINTSTATS
-	GC_printf1("Starting mark helper %lu\n", (unsigned long)id);
-#   endif
-    GC_release_mark_lock();
-    for (;;) {
-  	size_t n_on_stack;
-        size_t n_to_get;
-	mse *next;
-	mse * my_top;
-	mse * local_top;
-        mse * global_first_nonempty = GC_first_nonempty;
-
-    	GC_ASSERT(my_first_nonempty >= GC_mark_stack && 
-		  my_first_nonempty <= GC_mark_stack_top + 1);
-    	GC_ASSERT(global_first_nonempty >= GC_mark_stack && 
-		  global_first_nonempty <= GC_mark_stack_top + 1);
-	if (my_first_nonempty < global_first_nonempty) {
-	    my_first_nonempty = global_first_nonempty;
-        } else if (global_first_nonempty < my_first_nonempty) {
-	    GC_compare_and_exchange((word *)(&GC_first_nonempty), 
-				   (word) global_first_nonempty,
-				   (word) my_first_nonempty);
-	    /* If this fails, we just go ahead, without updating	*/
-	    /* GC_first_nonempty.					*/
-	}
-	/* Perhaps we should also update GC_first_nonempty, if it */
-	/* is less.  But that would require using atomic updates. */
-	my_top = GC_mark_stack_top;
-	n_on_stack = my_top - my_first_nonempty + 1;
-        if (0 == n_on_stack) {
-	    GC_acquire_mark_lock();
-            my_top = GC_mark_stack_top;
-            n_on_stack = my_top - my_first_nonempty + 1;
-	    if (0 == n_on_stack) {
-		GC_active_count--;
-		GC_ASSERT(GC_active_count <= GC_helper_count);
-		/* Other markers may redeposit objects	*/
-		/* on the stack.				*/
-		if (0 == GC_active_count) GC_notify_all_marker();
-		while (GC_active_count > 0
-		       && GC_first_nonempty > GC_mark_stack_top) {
-		    /* We will be notified if either GC_active_count	*/
-		    /* reaches zero, or if more objects are pushed on	*/
-		    /* the global mark stack.				*/
-		    GC_wait_marker();
-		}
-		if (GC_active_count == 0 &&
-		    GC_first_nonempty > GC_mark_stack_top) { 
-		    GC_bool need_to_notify = FALSE;
-		    /* The above conditions can't be falsified while we	*/
-		    /* hold the mark lock, since neither 		*/
-		    /* GC_active_count nor GC_mark_stack_top can	*/
-		    /* change.  GC_first_nonempty can only be		*/
-		    /* incremented asynchronously.  Thus we know that	*/
-		    /* both conditions actually held simultaneously.	*/
-		    GC_helper_count--;
-		    if (0 == GC_helper_count) need_to_notify = TRUE;
-#		    ifdef PRINTSTATS
-		      GC_printf1(
-		        "Finished mark helper %lu\n", (unsigned long)id);
-#   		    endif
-		    GC_release_mark_lock();
-		    if (need_to_notify) GC_notify_all_marker();
-		    return;
-		}
-		/* else there's something on the stack again, or	*/
-		/* another helper may push something.			*/
-		GC_active_count++;
-	        GC_ASSERT(GC_active_count > 0);
-		GC_release_mark_lock();
-		continue;
-	    } else {
-		GC_release_mark_lock();
-	    }
-	}
-	n_to_get = ENTRIES_TO_GET;
-	if (n_on_stack < 2 * ENTRIES_TO_GET) n_to_get = 1;
-	local_top = GC_steal_mark_stack(my_first_nonempty, my_top,
-					local_mark_stack, n_to_get,
-				        &my_first_nonempty);
-        GC_ASSERT(my_first_nonempty >= GC_mark_stack && 
-	          my_first_nonempty <= GC_mark_stack_top + 1);
-	GC_do_local_mark(local_mark_stack, local_top);
-    }
-}
-
-/* Perform Parallel mark.			*/
-/* We hold the GC lock, not the mark lock.	*/
-/* Currently runs until the mark stack is	*/
-/* empty.					*/
-void GC_do_parallel_mark()
-{
-    mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
-    mse * local_top;
-    mse * my_top;
-
-    GC_acquire_mark_lock();
-    GC_ASSERT(I_HOLD_LOCK());
-    /* This could be a GC_ASSERT, but it seems safer to keep it on	*/
-    /* all the time, especially since it's cheap.			*/
-    if (GC_help_wanted || GC_active_count != 0 || GC_helper_count != 0)
-	ABORT("Tried to start parallel mark in bad state");
-#   ifdef PRINTSTATS
-	GC_printf1("Starting marking for mark phase number %lu\n",
-		   (unsigned long)GC_mark_no);
-#   endif
-    GC_first_nonempty = GC_mark_stack;
-    GC_active_count = 0;
-    GC_helper_count = 1;
-    GC_help_wanted = TRUE;
-    GC_release_mark_lock();
-    GC_notify_all_marker();
-	/* Wake up potential helpers.	*/
-    GC_mark_local(local_mark_stack, 0);
-    GC_acquire_mark_lock();
-    GC_help_wanted = FALSE;
-    /* Done; clean up.	*/
-    while (GC_helper_count > 0) GC_wait_marker();
-    /* GC_helper_count cannot be incremented while GC_help_wanted == FALSE */
-#   ifdef PRINTSTATS
-	GC_printf1(
-	    "Finished marking for mark phase number %lu\n",
-	    (unsigned long)GC_mark_no);
-#   endif
-    GC_mark_no++;
-    GC_release_mark_lock();
-    GC_notify_all_marker();
-}
-
-
-/* Try to help out the marker, if it's running.	        */
-/* We do not hold the GC lock, but the requestor does.	*/
-void GC_help_marker(word my_mark_no)
-{
-    mse local_mark_stack[LOCAL_MARK_STACK_SIZE];
-    unsigned my_id;
-    mse * my_first_nonempty;
-
-    if (!GC_parallel) return;
-    GC_acquire_mark_lock();
-    while (GC_mark_no < my_mark_no
-           || !GC_help_wanted && GC_mark_no == my_mark_no) {
-      GC_wait_marker();
-    }
-    my_id = GC_helper_count;
-    if (GC_mark_no != my_mark_no || my_id >= GC_markers) {
-      /* Second test is useful only if original threads can also	*/
-      /* act as helpers.  Under Linux they can't.			*/
-      GC_release_mark_lock();
-      return;
-    }
-    GC_helper_count = my_id + 1;
-    GC_release_mark_lock();
-    GC_mark_local(local_mark_stack, my_id);
-    /* GC_mark_local decrements GC_helper_count. */
-}
-
-#endif /* PARALLEL_MARK */
-
-/* Allocate or reallocate space for mark stack of size s words  */
-/* May silently fail.						*/
-static void alloc_mark_stack(n)
-word n;
-{
-    mse * new_stack = (mse *)GC_scratch_alloc(n * sizeof(struct GC_ms_entry));
-    
-    GC_mark_stack_too_small = FALSE;
-    if (GC_mark_stack_size != 0) {
-        if (new_stack != 0) {
-          word displ = (word)GC_mark_stack & (GC_page_size - 1);
-          signed_word size = GC_mark_stack_size * sizeof(struct GC_ms_entry);
-          
-          /* Recycle old space */
-	      if (0 != displ) displ = GC_page_size - displ;
-	      size = (size - displ) & ~(GC_page_size - 1);
-	      if (size > 0) {
-	        GC_add_to_heap((struct hblk *)
-	      			((word)GC_mark_stack + displ), (word)size);
-	      }
-          GC_mark_stack = new_stack;
-          GC_mark_stack_size = n;
-	  GC_mark_stack_limit = new_stack + n;
-#	  ifdef CONDPRINT
-	    if (GC_print_stats) {
-	      GC_printf1("Grew mark stack to %lu frames\n",
-		    	 (unsigned long) GC_mark_stack_size);
-	    }
-#	  endif
-        } else {
-#	  ifdef CONDPRINT
-	    if (GC_print_stats) {
-	      GC_printf1("Failed to grow mark stack to %lu frames\n",
-		    	 (unsigned long) n);
-	    }
-#	  endif
-        }
-    } else {
-        if (new_stack == 0) {
-            GC_err_printf0("No space for mark stack\n");
-            EXIT();
-        }
-        GC_mark_stack = new_stack;
-        GC_mark_stack_size = n;
-	GC_mark_stack_limit = new_stack + n;
-    }
-    GC_mark_stack_top = GC_mark_stack-1;
-}
-
-void GC_mark_init()
-{
-    alloc_mark_stack(INITIAL_MARK_STACK_SIZE);
-}
-
-/*
- * Push all locations between b and t onto the mark stack.
- * b is the first location to be checked. t is one past the last
- * location to be checked.
- * Should only be used if there is no possibility of mark stack
- * overflow.
- */
-void GC_push_all(bottom, top)
-ptr_t bottom;
-ptr_t top;
-{
-    register word length;
-    
-    bottom = (ptr_t)(((word) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
-    top = (ptr_t)(((word) top) & ~(ALIGNMENT-1));
-    if (top == 0 || bottom == top) return;
-    GC_mark_stack_top++;
-    if (GC_mark_stack_top >= GC_mark_stack_limit) {
-	ABORT("unexpected mark stack overflow");
-    }
-    length = top - bottom;
-#   if GC_DS_TAGS > ALIGNMENT - 1
-	length += GC_DS_TAGS;
-	length &= ~GC_DS_TAGS;
-#   endif
-    GC_mark_stack_top -> mse_start = (word *)bottom;
-    GC_mark_stack_top -> mse_descr = length;
-}
-
-/*
- * Analogous to the above, but push only those pages h with dirty_fn(h) != 0.
- * We use push_fn to actually push the block.
- * Used both to selectively push dirty pages, or to push a block
- * in piecemeal fashion, to allow for more marking concurrency.
- * Will not overflow mark stack if push_fn pushes a small fixed number
- * of entries.  (This is invoked only if push_fn pushes a single entry,
- * or if it marks each object before pushing it, thus ensuring progress
- * in the event of a stack overflow.)
- */
-void GC_push_selected(bottom, top, dirty_fn, push_fn)
-ptr_t bottom;
-ptr_t top;
-int (*dirty_fn) GC_PROTO((struct hblk * h));
-void (*push_fn) GC_PROTO((ptr_t bottom, ptr_t top));
-{
-    register struct hblk * h;
-
-    bottom = (ptr_t)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
-    top = (ptr_t)(((long) top) & ~(ALIGNMENT-1));
-
-    if (top == 0 || bottom == top) return;
-    h = HBLKPTR(bottom + HBLKSIZE);
-    if (top <= (ptr_t) h) {
-  	if ((*dirty_fn)(h-1)) {
-	    (*push_fn)(bottom, top);
-	}
-	return;
-    }
-    if ((*dirty_fn)(h-1)) {
-        (*push_fn)(bottom, (ptr_t)h);
-    }
-    while ((ptr_t)(h+1) <= top) {
-	if ((*dirty_fn)(h)) {
-	    if ((word)(GC_mark_stack_top - GC_mark_stack)
-		> 3 * GC_mark_stack_size / 4) {
-	 	/* Danger of mark stack overflow */
-		(*push_fn)((ptr_t)h, top);
-		return;
-	    } else {
-		(*push_fn)((ptr_t)h, (ptr_t)(h+1));
-	    }
-	}
-	h++;
-    }
-    if ((ptr_t)h != top) {
-	if ((*dirty_fn)(h)) {
-            (*push_fn)((ptr_t)h, top);
-        }
-    }
-    if (GC_mark_stack_top >= GC_mark_stack_limit) {
-        ABORT("unexpected mark stack overflow");
-    }
-}
-
-# ifndef SMALL_CONFIG
-
-#ifdef PARALLEL_MARK
-    /* Break up root sections into page size chunks to better spread 	*/
-    /* out work.							*/
-    GC_bool GC_true_func(struct hblk *h) { return TRUE; }
-#   define GC_PUSH_ALL(b,t) GC_push_selected(b,t,GC_true_func,GC_push_all);
-#else
-#   define GC_PUSH_ALL(b,t) GC_push_all(b,t);
-#endif
-
-
-void GC_push_conditional(bottom, top, all)
-ptr_t bottom;
-ptr_t top;
-int all;
-{
-    if (all) {
-      if (GC_dirty_maintained) {
-#	ifdef PROC_VDB
-	    /* Pages that were never dirtied cannot contain pointers	*/
-	    GC_push_selected(bottom, top, GC_page_was_ever_dirty, GC_push_all);
-#	else
-	    GC_push_all(bottom, top);
-#	endif
-      } else {
-      	GC_push_all(bottom, top);
-      }
-    } else {
-	GC_push_selected(bottom, top, GC_page_was_dirty, GC_push_all);
-    }
-}
-#endif
-
-# if defined(MSWIN32) || defined(MSWINCE)
-  void __cdecl GC_push_one(p)
-# else
-  void GC_push_one(p)
-# endif
-word p;
-{
-    GC_PUSH_ONE_STACK(p, MARKED_FROM_REGISTER);
-}
-
-struct GC_ms_entry *GC_mark_and_push(obj, mark_stack_ptr, mark_stack_limit, src)
-GC_PTR obj;
-struct GC_ms_entry * mark_stack_ptr;
-struct GC_ms_entry * mark_stack_limit;
-GC_PTR *src;
-{
-   PREFETCH(obj);
-   PUSH_CONTENTS(obj, mark_stack_ptr /* modified */, mark_stack_limit, src,
-		 was_marked /* internally generated exit label */);
-   return mark_stack_ptr;
-}
-
-# ifdef __STDC__
-#   define BASE(p) (word)GC_base((void *)(p))
-# else
-#   define BASE(p) (word)GC_base((char *)(p))
-# endif
-
-/* Mark and push (i.e. gray) a single object p onto the main	*/
-/* mark stack.  Consider p to be valid if it is an interior	*/
-/* pointer.							*/
-/* The object p has passed a preliminary pointer validity	*/
-/* test, but we do not definitely know whether it is valid.	*/
-/* Mark bits are NOT atomically updated.  Thus this must be the	*/
-/* only thread setting them.					*/
-# if defined(PRINT_BLACK_LIST) || defined(KEEP_BACK_PTRS)
-    void GC_mark_and_push_stack(p, source)
-    ptr_t source;
-# else
-    void GC_mark_and_push_stack(p)
-#   define source 0
-# endif
-register word p;
-{
-    register word r;
-    register hdr * hhdr; 
-    register int displ;
-  
-    GET_HDR(p, hhdr);
-    if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
-        if (hhdr != 0) {
-          r = BASE(p);
-	  hhdr = HDR(r);
-	  displ = BYTES_TO_WORDS(HBLKDISPL(r));
-	}
-    } else {
-        register map_entry_type map_entry;
-        
-        displ = HBLKDISPL(p);
-        map_entry = MAP_ENTRY((hhdr -> hb_map), displ);
-        if (map_entry >= MAX_OFFSET) {
-          if (map_entry == OFFSET_TOO_BIG || !GC_all_interior_pointers) {
-              r = BASE(p);
-	      displ = BYTES_TO_WORDS(HBLKDISPL(r));
-	      if (r == 0) hhdr = 0;
-          } else {
-	      /* Offset invalid, but map reflects interior pointers 	*/
-              hhdr = 0;
-          }
-        } else {
-          displ = BYTES_TO_WORDS(displ);
-          displ -= map_entry;
-          r = (word)((word *)(HBLKPTR(p)) + displ);
-        }
-    }
-    /* If hhdr != 0 then r == GC_base(p), only we did it faster. */
-    /* displ is the word index within the block.		 */
-    if (hhdr == 0) {
-#	ifdef PRINT_BLACK_LIST
-	  GC_add_to_black_list_stack(p, source);
-#	else
-	  GC_add_to_black_list_stack(p);
-#	endif
-#	undef source  /* In case we had to define it. */
-    } else {
-	if (!mark_bit_from_hdr(hhdr, displ)) {
-	    set_mark_bit_from_hdr(hhdr, displ);
- 	    GC_STORE_BACK_PTR(source, (ptr_t)r);
-	    PUSH_OBJ((word *)r, hhdr, GC_mark_stack_top,
-	             GC_mark_stack_limit);
-	}
-    }
-}
-
-# ifdef TRACE_BUF
-
-# define TRACE_ENTRIES 1000
-
-struct trace_entry {
-    char * kind;
-    word gc_no;
-    word words_allocd;
-    word arg1;
-    word arg2;
-} GC_trace_buf[TRACE_ENTRIES];
-
-int GC_trace_buf_ptr = 0;
-
-void GC_add_trace_entry(char *kind, word arg1, word arg2)
-{
-    GC_trace_buf[GC_trace_buf_ptr].kind = kind;
-    GC_trace_buf[GC_trace_buf_ptr].gc_no = GC_gc_no;
-    GC_trace_buf[GC_trace_buf_ptr].words_allocd = GC_words_allocd;
-    GC_trace_buf[GC_trace_buf_ptr].arg1 = arg1 ^ 0x80000000;
-    GC_trace_buf[GC_trace_buf_ptr].arg2 = arg2 ^ 0x80000000;
-    GC_trace_buf_ptr++;
-    if (GC_trace_buf_ptr >= TRACE_ENTRIES) GC_trace_buf_ptr = 0;
-}
-
-void GC_print_trace(word gc_no, GC_bool lock)
-{
-    int i;
-    struct trace_entry *p;
-    
-    if (lock) LOCK();
-    for (i = GC_trace_buf_ptr-1; i != GC_trace_buf_ptr; i--) {
-    	if (i < 0) i = TRACE_ENTRIES-1;
-    	p = GC_trace_buf + i;
-    	if (p -> gc_no < gc_no || p -> kind == 0) return;
-    	printf("Trace:%s (gc:%d,words:%d) 0x%X, 0x%X\n",
-    		p -> kind, p -> gc_no, p -> words_allocd,
-    		(p -> arg1) ^ 0x80000000, (p -> arg2) ^ 0x80000000);
-    }
-    printf("Trace incomplete\n");
-    if (lock) UNLOCK();
-}
-
-# endif /* TRACE_BUF */
-
-/*
- * A version of GC_push_all that treats all interior pointers as valid
- * and scans the entire region immediately, in case the contents
- * change.
- */
-void GC_push_all_eager(bottom, top)
-ptr_t bottom;
-ptr_t top;
-{
-    word * b = (word *)(((long) bottom + ALIGNMENT-1) & ~(ALIGNMENT-1));
-    word * t = (word *)(((long) top) & ~(ALIGNMENT-1));
-    register word *p;
-    register word q;
-    register word *lim;
-    register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
-    register ptr_t least_ha = GC_least_plausible_heap_addr;
-#   define GC_greatest_plausible_heap_addr greatest_ha
-#   define GC_least_plausible_heap_addr least_ha
-
-    if (top == 0) return;
-    /* check all pointers in range and put in push if they appear */
-    /* to be valid.						  */
-      lim = t - 1 /* longword */;
-      for (p = b; p <= lim; p = (word *)(((char *)p) + ALIGNMENT)) {
-	q = *p;
-	GC_PUSH_ONE_STACK(q, p);
-      }
-#   undef GC_greatest_plausible_heap_addr
-#   undef GC_least_plausible_heap_addr
-}
-
-#ifndef THREADS
-/*
- * A version of GC_push_all that treats all interior pointers as valid
- * and scans part of the area immediately, to make sure that saved
- * register values are not lost.
- * Cold_gc_frame delimits the stack section that must be scanned
- * eagerly.  A zero value indicates that no eager scanning is needed.
- */
-void GC_push_all_stack_partially_eager(bottom, top, cold_gc_frame)
-ptr_t bottom;
-ptr_t top;
-ptr_t cold_gc_frame;
-{
-  if (GC_all_interior_pointers) {
-#   define EAGER_BYTES 1024
-    /* Push the hot end of the stack eagerly, so that register values   */
-    /* saved inside GC frames are marked before they disappear.		*/
-    /* The rest of the marking can be deferred until later.		*/
-    if (0 == cold_gc_frame) {
-	GC_push_all_stack(bottom, top);
-	return;
-    }
-#   ifdef STACK_GROWS_DOWN
-	GC_push_all(cold_gc_frame - sizeof(ptr_t), top);
-	GC_push_all_eager(bottom, cold_gc_frame);
-#   else /* STACK_GROWS_UP */
-	GC_push_all(bottom, cold_gc_frame + sizeof(ptr_t));
-	GC_push_all_eager(cold_gc_frame, top);
-#   endif /* STACK_GROWS_UP */
-  } else {
-    GC_push_all_eager(bottom, top);
-  }
-# ifdef TRACE_BUF
-      GC_add_trace_entry("GC_push_all_stack", bottom, top);
-# endif
-}
-#endif /* !THREADS */
-
-void GC_push_all_stack(bottom, top)
-ptr_t bottom;
-ptr_t top;
-{
-  if (GC_all_interior_pointers) {
-    GC_push_all(bottom, top);
-  } else {
-    GC_push_all_eager(bottom, top);
-  }
-}
-
-#if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)
-/* Push all objects reachable from marked objects in the given block */
-/* of size 1 objects.						     */
-void GC_push_marked1(h, hhdr)
-struct hblk *h;
-register hdr * hhdr;
-{
-    word * mark_word_addr = &(hhdr->hb_marks[0]);
-    register word *p;
-    word *plim;
-    register int i;
-    register word q;
-    register word mark_word;
-    register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
-    register ptr_t least_ha = GC_least_plausible_heap_addr;
-    register mse * mark_stack_top = GC_mark_stack_top;
-    register mse * mark_stack_limit = GC_mark_stack_limit;
-#   define GC_mark_stack_top mark_stack_top
-#   define GC_mark_stack_limit mark_stack_limit
-#   define GC_greatest_plausible_heap_addr greatest_ha
-#   define GC_least_plausible_heap_addr least_ha
-    
-    p = (word *)(h->hb_body);
-    plim = (word *)(((word)h) + HBLKSIZE);
-
-    /* go through all words in block */
-	while( p < plim )  {
-	    mark_word = *mark_word_addr++;
-	    i = 0;
-	    while(mark_word != 0) {
-	      if (mark_word & 1) {
-	          q = p[i];
-	          GC_PUSH_ONE_HEAP(q, p + i);
-	      }
-	      i++;
-	      mark_word >>= 1;
-	    }
-	    p += WORDSZ;
-	}
-#   undef GC_greatest_plausible_heap_addr
-#   undef GC_least_plausible_heap_addr        
-#   undef GC_mark_stack_top
-#   undef GC_mark_stack_limit
-    GC_mark_stack_top = mark_stack_top;
-}
-
-
-#ifndef UNALIGNED
-
-/* Push all objects reachable from marked objects in the given block */
-/* of size 2 objects.						     */
-void GC_push_marked2(h, hhdr)
-struct hblk *h;
-register hdr * hhdr;
-{
-    word * mark_word_addr = &(hhdr->hb_marks[0]);
-    register word *p;
-    word *plim;
-    register int i;
-    register word q;
-    register word mark_word;
-    register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
-    register ptr_t least_ha = GC_least_plausible_heap_addr;
-    register mse * mark_stack_top = GC_mark_stack_top;
-    register mse * mark_stack_limit = GC_mark_stack_limit;
-#   define GC_mark_stack_top mark_stack_top
-#   define GC_mark_stack_limit mark_stack_limit
-#   define GC_greatest_plausible_heap_addr greatest_ha
-#   define GC_least_plausible_heap_addr least_ha
-    
-    p = (word *)(h->hb_body);
-    plim = (word *)(((word)h) + HBLKSIZE);
-
-    /* go through all words in block */
-	while( p < plim )  {
-	    mark_word = *mark_word_addr++;
-	    i = 0;
-	    while(mark_word != 0) {
-	      if (mark_word & 1) {
-	          q = p[i];
-	          GC_PUSH_ONE_HEAP(q, p + i);
-	          q = p[i+1];
-	          GC_PUSH_ONE_HEAP(q, p + i);
-	      }
-	      i += 2;
-	      mark_word >>= 2;
-	    }
-	    p += WORDSZ;
-	}
-#   undef GC_greatest_plausible_heap_addr
-#   undef GC_least_plausible_heap_addr        
-#   undef GC_mark_stack_top
-#   undef GC_mark_stack_limit
-    GC_mark_stack_top = mark_stack_top;
-}
-
-/* Push all objects reachable from marked objects in the given block */
-/* of size 4 objects.						     */
-/* There is a risk of mark stack overflow here.  But we handle that. */
-/* And only unmarked objects get pushed, so it's not very likely.    */
-void GC_push_marked4(h, hhdr)
-struct hblk *h;
-register hdr * hhdr;
-{
-    word * mark_word_addr = &(hhdr->hb_marks[0]);
-    register word *p;
-    word *plim;
-    register int i;
-    register word q;
-    register word mark_word;
-    register ptr_t greatest_ha = GC_greatest_plausible_heap_addr;
-    register ptr_t least_ha = GC_least_plausible_heap_addr;
-    register mse * mark_stack_top = GC_mark_stack_top;
-    register mse * mark_stack_limit = GC_mark_stack_limit;
-#   define GC_mark_stack_top mark_stack_top
-#   define GC_mark_stack_limit mark_stack_limit
-#   define GC_greatest_plausible_heap_addr greatest_ha
-#   define GC_least_plausible_heap_addr least_ha
-    
-    p = (word *)(h->hb_body);
-    plim = (word *)(((word)h) + HBLKSIZE);
-
-    /* go through all words in block */
-	while( p < plim )  {
-	    mark_word = *mark_word_addr++;
-	    i = 0;
-	    while(mark_word != 0) {
-	      if (mark_word & 1) {
-	          q = p[i];
-	          GC_PUSH_ONE_HEAP(q, p + i);
-	          q = p[i+1];
-	          GC_PUSH_ONE_HEAP(q, p + i + 1);
-	          q = p[i+2];
-	          GC_PUSH_ONE_HEAP(q, p + i + 2);
-	          q = p[i+3];
-	          GC_PUSH_ONE_HEAP(q, p + i + 3);
-	      }
-	      i += 4;
-	      mark_word >>= 4;
-	    }
-	    p += WORDSZ;
-	}
-#   undef GC_greatest_plausible_heap_addr
-#   undef GC_least_plausible_heap_addr        
-#   undef GC_mark_stack_top
-#   undef GC_mark_stack_limit
-    GC_mark_stack_top = mark_stack_top;
-}
-
-#endif /* UNALIGNED */
-
-#endif /* SMALL_CONFIG */
-
-/* Push all objects reachable from marked objects in the given block */
-void GC_push_marked(h, hhdr)
-struct hblk *h;
-register hdr * hhdr;
-{
-    register int sz = hhdr -> hb_sz;
-    register int descr = hhdr -> hb_descr;
-    register word * p;
-    register int word_no;
-    register word * lim;
-    register mse * GC_mark_stack_top_reg;
-    register mse * mark_stack_limit = GC_mark_stack_limit;
-    
-    /* Some quick shortcuts: */
-	if ((0 | GC_DS_LENGTH) == descr) return;
-        if (GC_block_empty(hhdr)/* nothing marked */) return;
-    GC_n_rescuing_pages++;
-    GC_objects_are_marked = TRUE;
-    if (sz > MAXOBJSZ) {
-        lim = (word *)h;
-    } else {
-        lim = (word *)(h + 1) - sz;
-    }
-    
-    switch(sz) {
-#   if !defined(SMALL_CONFIG) && !defined(USE_MARK_BYTES)   
-     case 1:
-       GC_push_marked1(h, hhdr);
-       break;
-#   endif
-#   if !defined(SMALL_CONFIG) && !defined(UNALIGNED) && \
-       !defined(USE_MARK_BYTES)
-     case 2:
-       GC_push_marked2(h, hhdr);
-       break;
-     case 4:
-       GC_push_marked4(h, hhdr);
-       break;
-#   endif       
-     default:
-      GC_mark_stack_top_reg = GC_mark_stack_top;
-      for (p = (word *)h, word_no = 0; p <= lim; p += sz, word_no += sz) {
-         if (mark_bit_from_hdr(hhdr, word_no)) {
-           /* Mark from fields inside the object */
-             PUSH_OBJ((word *)p, hhdr, GC_mark_stack_top_reg, mark_stack_limit);
-#	     ifdef GATHERSTATS
-		/* Subtract this object from total, since it was	*/
-		/* added in twice.					*/
-		GC_composite_in_use -= sz;
-#	     endif
-         }
-      }
-      GC_mark_stack_top = GC_mark_stack_top_reg;
-    }
-}
-
-#ifndef SMALL_CONFIG
-/* Test whether any page in the given block is dirty	*/
-GC_bool GC_block_was_dirty(h, hhdr)
-struct hblk *h;
-register hdr * hhdr;
-{
-    register int sz = hhdr -> hb_sz;
-    
-    if (sz < MAXOBJSZ) {
-         return(GC_page_was_dirty(h));
-    } else {
-    	 register ptr_t p = (ptr_t)h;
-         sz = WORDS_TO_BYTES(sz);
-         while (p < (ptr_t)h + sz) {
-             if (GC_page_was_dirty((struct hblk *)p)) return(TRUE);
-             p += HBLKSIZE;
-         }
-         return(FALSE);
-    }
-}
-#endif /* SMALL_CONFIG */
-
-/* Similar to GC_push_next_marked, but return address of next block	*/
-struct hblk * GC_push_next_marked(h)
-struct hblk *h;
-{
-    register hdr * hhdr;
-    
-    h = GC_next_used_block(h);
-    if (h == 0) return(0);
-    hhdr = HDR(h);
-    GC_push_marked(h, hhdr);
-    return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
-}
-
-#ifndef SMALL_CONFIG
-/* Identical to above, but mark only from dirty pages	*/
-struct hblk * GC_push_next_marked_dirty(h)
-struct hblk *h;
-{
-    register hdr * hhdr;
-    
-    if (!GC_dirty_maintained) { ABORT("dirty bits not set up"); }
-    for (;;) {
-        h = GC_next_used_block(h);
-        if (h == 0) return(0);
-        hhdr = HDR(h);
-#	ifdef STUBBORN_ALLOC
-          if (hhdr -> hb_obj_kind == STUBBORN) {
-            if (GC_page_was_changed(h) && GC_block_was_dirty(h, hhdr)) {
-                break;
-            }
-          } else {
-            if (GC_block_was_dirty(h, hhdr)) break;
-          }
-#	else
-	  if (GC_block_was_dirty(h, hhdr)) break;
-#	endif
-        h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
-    }
-    GC_push_marked(h, hhdr);
-    return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
-}
-#endif
-
-/* Similar to above, but for uncollectable pages.  Needed since we	*/
-/* do not clear marks for such pages, even for full collections.	*/
-struct hblk * GC_push_next_marked_uncollectable(h)
-struct hblk *h;
-{
-    register hdr * hhdr = HDR(h);
-    
-    for (;;) {
-        h = GC_next_used_block(h);
-        if (h == 0) return(0);
-        hhdr = HDR(h);
-	if (hhdr -> hb_obj_kind == UNCOLLECTABLE) break;
-        h += OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
-    }
-    GC_push_marked(h, hhdr);
-    return(h + OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz));
-}
-
-