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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1994 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 "private/gc_priv.h"
/*
* This file contains the functions:
* ptr_t GC_build_flXXX(h, old_fl)
* void GC_new_hblk(size, kind)
*/
#ifndef SMALL_CONFIG
/* Build a free list for size 2 (words) cleared objects inside */
/* hblk h. Set the last link to be ofl. Return a pointer to the */
/* first free list entry. */
STATIC ptr_t GC_build_fl_clear2(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
p[0] = (word)ofl;
p[1] = 0;
p[2] = (word)p;
p[3] = 0;
p += 4;
for (; (word)p < (word)lim; p += 4) {
p[0] = (word)(p-2);
p[1] = 0;
p[2] = (word)p;
p[3] = 0;
}
return (ptr_t)(p-2);
}
/* The same for size 4 cleared objects. */
STATIC ptr_t GC_build_fl_clear4(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
p[0] = (word)ofl;
p[1] = 0;
p[2] = 0;
p[3] = 0;
p += 4;
for (; (word)p < (word)lim; p += 4) {
GC_PREFETCH_FOR_WRITE((ptr_t)(p + 64));
p[0] = (word)(p-4);
p[1] = 0;
CLEAR_DOUBLE(p+2);
}
return (ptr_t)(p-4);
}
/* The same for size 2 uncleared objects. */
STATIC ptr_t GC_build_fl2(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
p[0] = (word)ofl;
p[2] = (word)p;
p += 4;
for (; (word)p < (word)lim; p += 4) {
p[0] = (word)(p-2);
p[2] = (word)p;
}
return (ptr_t)(p-2);
}
/* The same for size 4 uncleared objects. */
STATIC ptr_t GC_build_fl4(struct hblk *h, ptr_t ofl)
{
word * p = (word *)(h -> hb_body);
word * lim = (word *)(h + 1);
p[0] = (word)ofl;
p[4] = (word)p;
p += 8;
for (; (word)p < (word)lim; p += 8) {
GC_PREFETCH_FOR_WRITE((ptr_t)(p + 64));
p[0] = (word)(p-4);
p[4] = (word)p;
}
return (ptr_t)(p-4);
}
#endif /* !SMALL_CONFIG */
/* Build a free list for objects of size sz inside heap block h. */
/* Clear objects inside h if clear is set. Add list to the end of */
/* the free list we build. Return the new free list. */
/* This could be called without the allocation lock, if we ensure that */
/* there is no concurrent collection which might reclaim objects that */
/* we have not yet allocated. */
GC_INNER ptr_t GC_build_fl(struct hblk *h, size_t sz, GC_bool clear,
ptr_t list)
{
word *p, *prev;
word *last_object; /* points to last object in new hblk */
/* Do a few prefetches here, just because it's cheap. */
/* If we were more serious about it, these should go inside */
/* the loops. But write prefetches usually don't seem to */
/* matter much. */
GC_PREFETCH_FOR_WRITE((ptr_t)h);
GC_PREFETCH_FOR_WRITE((ptr_t)h + 128);
GC_PREFETCH_FOR_WRITE((ptr_t)h + 256);
GC_PREFETCH_FOR_WRITE((ptr_t)h + 378);
# ifndef SMALL_CONFIG
/* Handle small objects sizes more efficiently. For larger objects */
/* the difference is less significant. */
switch (sz) {
case 2: if (clear) {
return GC_build_fl_clear2(h, list);
} else {
return GC_build_fl2(h, list);
}
case 4: if (clear) {
return GC_build_fl_clear4(h, list);
} else {
return GC_build_fl4(h, list);
}
default:
break;
}
# endif /* !SMALL_CONFIG */
/* Clear the page if necessary. */
if (clear) BZERO(h, HBLKSIZE);
/* Add objects to free list */
p = (word *)(h -> hb_body) + sz; /* second object in *h */
prev = (word *)(h -> hb_body); /* One object behind p */
last_object = (word *)((char *)h + HBLKSIZE);
last_object -= sz;
/* Last place for last object to start */
/* make a list of all objects in *h with head as last object */
while ((word)p <= (word)last_object) {
/* current object's link points to last object */
obj_link(p) = (ptr_t)prev;
prev = p;
p += sz;
}
p -= sz; /* p now points to last object */
/* Put p (which is now head of list of objects in *h) as first */
/* pointer in the appropriate free list for this size. */
*(ptr_t *)h = list;
return (ptr_t)p;
}
/* Allocate a new heapblock for small objects of the given size in */
/* granules and kind. Add all of the heapblock's objects to the */
/* free list for objects of that size. Set all mark bits */
/* if objects are uncollectible. Will fail to do anything if we */
/* are out of memory. */
GC_INNER void GC_new_hblk(size_t gran, int k)
{
struct hblk *h; /* the new heap block */
GC_STATIC_ASSERT((sizeof (struct hblk)) == HBLKSIZE);
GC_ASSERT(I_HOLD_LOCK());
/* Allocate a new heap block. */
h = GC_allochblk(GRANULES_TO_BYTES(gran), k, 0 /* flags */, 0);
if (EXPECT(NULL == h, FALSE)) return; /* out of memory */
/* Mark all objects if appropriate. */
if (IS_UNCOLLECTABLE(k)) GC_set_hdr_marks(HDR(h));
/* Build the free list */
GC_obj_kinds[k].ok_freelist[gran] =
GC_build_fl(h, GRANULES_TO_WORDS(gran),
GC_debugging_started || GC_obj_kinds[k].ok_init,
(ptr_t)GC_obj_kinds[k].ok_freelist[gran]);
}
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