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* Use a set of dedicated macros to access and modify free cells.

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This commit is contained in:
Dirk Herrmann 2000-07-10 14:25:53 +00:00
parent f706a58b67
commit 3f5d82cd9a
3 changed files with 50 additions and 27 deletions
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16
libguile/ChangeLog
View file

@ -1,3 +1,19 @@
2000-07-10 Dirk Herrmann <D.Herrmann@tu-bs.de>
* gc.h (SCM_SET_FREE_CELL_TYPE, SCM_SET_FREE_CELL_CDR,
SCM_FREE_CELL_P, SCM_FREE_CELL_CDR): Added since free cells
should not be accessed via SCM_C[AD]R. Further, using dedicated
macros to access free cells allows all other cell accessing macros
to treat acesses to free cells as errors, thus enabling better
error checks for cell accesses. SCM_FREE_CELL_P is supposed to
replace SCM_FREEP some time.
* gc.h (SCM_NEWCELL, SCM_NEWCELL2), gc.c (map_free_list,
free_list_length, scm_check_freelist, scm_debug_newcell,
scm_debug_newcell2, freelist_length, scm_gc_for_newcell,
scm_gc_mark, scm_gc_sweep, init_heap_seg): Only use the dedicated
cell accessors when accessing free cells.
2000-07-10 Dirk Herrmann <D.Herrmann@tu-bs.de> 2000-07-10 Dirk Herrmann <D.Herrmann@tu-bs.de>
* gc.h (SCM_CELL_WORD, SCM_CELL_OBJECT): Treat the referenced * gc.h (SCM_CELL_WORD, SCM_CELL_OBJECT): Treat the referenced

41
libguile/gc.c
View file

@ -314,7 +314,7 @@ map_free_list (scm_freelist_t *master, SCM freelist)
int last_seg = -1, count = 0; int last_seg = -1, count = 0;
SCM f; SCM f;
for (f = freelist; SCM_NIMP (f); f = SCM_CDR (f)) for (f = freelist; !SCM_NULLP (f); f = SCM_FREE_CELL_CDR (f))
{ {
int this_seg = which_seg (f); int this_seg = which_seg (f);
@ -365,8 +365,8 @@ free_list_length (char *title, int i, SCM freelist)
{ {
SCM ls; SCM ls;
int n = 0; int n = 0;
for (ls = freelist; SCM_NNULLP (ls); ls = SCM_CDR (ls)) for (ls = freelist; !SCM_NULLP (ls); ls = SCM_FREE_CELL_CDR (ls))
if (SCM_CELL_TYPE (ls) == scm_tc_free_cell) if (SCM_FREE_CELL_P (ls))
++n; ++n;
else else
{ {
@ -441,8 +441,8 @@ scm_check_freelist (SCM freelist)
SCM f; SCM f;
int i = 0; int i = 0;
for (f = freelist; SCM_NIMP (f); f = SCM_CDR (f), i++) for (f = freelist; !SCM_NULLP (f); f = SCM_FREE_CELL_CDR (f), i++)
if (SCM_CAR (f) != (SCM) scm_tc_free_cell) if (!SCM_FREE_CELL_P (f))
{ {
fprintf (stderr, "Bad cell in freelist on newcell %lu: %d'th elt\n", fprintf (stderr, "Bad cell in freelist on newcell %lu: %d'th elt\n",
scm_newcell_count, i); scm_newcell_count, i);
@ -479,13 +479,13 @@ scm_debug_newcell (void)
/* The rest of this is supposed to be identical to the SCM_NEWCELL /* The rest of this is supposed to be identical to the SCM_NEWCELL
macro. */ macro. */
if (SCM_IMP (scm_freelist)) if (SCM_NULLP (scm_freelist))
new = scm_gc_for_newcell (&scm_master_freelist, &scm_freelist); new = scm_gc_for_newcell (&scm_master_freelist, &scm_freelist);
else else
{ {
new = scm_freelist; new = scm_freelist;
scm_freelist = SCM_CDR (scm_freelist); scm_freelist = SCM_FREE_CELL_CDR (scm_freelist);
SCM_SETCAR (new, scm_tc16_allocated); SCM_SET_FREE_CELL_TYPE (new, scm_tc16_allocated);
} }
return new; return new;
@ -505,13 +505,13 @@ scm_debug_newcell2 (void)
/* The rest of this is supposed to be identical to the SCM_NEWCELL /* The rest of this is supposed to be identical to the SCM_NEWCELL
macro. */ macro. */
if (SCM_IMP (scm_freelist2)) if (SCM_NULLP (scm_freelist2))
new = scm_gc_for_newcell (&scm_master_freelist2, &scm_freelist2); new = scm_gc_for_newcell (&scm_master_freelist2, &scm_freelist2);
else else
{ {
new = scm_freelist2; new = scm_freelist2;
scm_freelist2 = SCM_CDR (scm_freelist2); scm_freelist2 = SCM_FREE_CELL_CDR (scm_freelist2);
SCM_SETCAR (new, scm_tc16_allocated); SCM_SET_FREE_CELL_TYPE (new, scm_tc16_allocated);
} }
return new; return new;
@ -534,7 +534,7 @@ static unsigned long
freelist_length (SCM freelist) freelist_length (SCM freelist)
{ {
int n; int n;
for (n = 0; SCM_NNULLP (freelist); freelist = SCM_CDR (freelist)) for (n = 0; !SCM_NULLP (freelist); freelist = SCM_FREE_CELL_CDR (freelist))
++n; ++n;
return n; return n;
} }
@ -741,8 +741,8 @@ scm_gc_for_newcell (scm_freelist_t *master, SCM *freelist)
} }
while (SCM_NULLP (cell)); while (SCM_NULLP (cell));
--scm_ints_disabled; --scm_ints_disabled;
*freelist = SCM_CDR (cell); *freelist = SCM_FREE_CELL_CDR (cell);
SCM_SET_CELL_TYPE (cell, scm_tc16_allocated); SCM_SET_FREE_CELL_TYPE (cell, scm_tc16_allocated);
return cell; return cell;
} }
@ -919,7 +919,7 @@ gc_mark_loop:
return; return;
gc_mark_nimp: gc_mark_nimp:
if (SCM_NCELLP (ptr)) if (!SCM_CELLP (ptr))
SCM_MISC_ERROR ("rogue pointer in heap", SCM_EOL); SCM_MISC_ERROR ("rogue pointer in heap", SCM_EOL);
switch (SCM_TYP7 (ptr)) switch (SCM_TYP7 (ptr))
@ -1264,7 +1264,6 @@ scm_mark_locations (SCM_STACKITEM x[], scm_sizet n)
scm_gc_mark (* (SCM *) &x[m]); scm_gc_mark (* (SCM *) &x[m]);
break; break;
} }
} }
} }
} }
@ -1321,7 +1320,7 @@ gc_sweep_freelist_finish (scm_freelist_t *freelist)
{ {
int collected; int collected;
*freelist->clustertail = freelist->cells; *freelist->clustertail = freelist->cells;
if (SCM_NNULLP (freelist->cells)) if (!SCM_NULLP (freelist->cells))
{ {
SCM c = freelist->cells; SCM c = freelist->cells;
SCM_SETCAR (c, SCM_CDR (c)); SCM_SETCAR (c, SCM_CDR (c));
@ -1574,7 +1573,7 @@ scm_gc_sweep ()
SCM_MISC_ERROR ("unknown type", SCM_EOL); SCM_MISC_ERROR ("unknown type", SCM_EOL);
} }
#if 0 #if 0
if (SCM_CAR (scmptr) == (SCM) scm_tc_free_cell) if (SCM_FREE_CELL_P (scmptr))
exit (2); exit (2);
#endif #endif
if (!--left_to_collect) if (!--left_to_collect)
@ -1594,7 +1593,7 @@ scm_gc_sweep ()
conservative collector might trace it as some other type conservative collector might trace it as some other type
of object. */ of object. */
SCM_SET_CELL_TYPE (scmptr, scm_tc_free_cell); SCM_SET_CELL_TYPE (scmptr, scm_tc_free_cell);
SCM_SETCDR (scmptr, nfreelist); SCM_SET_FREE_CELL_CDR (scmptr, nfreelist);
nfreelist = scmptr; nfreelist = scmptr;
} }
@ -1930,11 +1929,11 @@ init_heap_seg (SCM_CELLPTR seg_org, scm_sizet size, scm_freelist_t *freelist)
SCM scmptr = PTR2SCM (ptr); SCM scmptr = PTR2SCM (ptr);
SCM_SET_CELL_TYPE (scmptr, scm_tc_free_cell); SCM_SET_CELL_TYPE (scmptr, scm_tc_free_cell);
SCM_SETCDR (scmptr, PTR2SCM (ptr + span)); SCM_SET_FREE_CELL_CDR (scmptr, PTR2SCM (ptr + span));
ptr += span; ptr += span;
} }
SCM_SETCDR (PTR2SCM (ptr - span), SCM_EOL); SCM_SET_FREE_CELL_CDR (PTR2SCM (ptr - span), SCM_EOL);
} }
/* Patch up the last cluster pointer in the segment /* Patch up the last cluster pointer in the segment

20
libguile/gc.h
View file

@ -146,13 +146,21 @@ typedef scm_cell * SCM_CELLPTR;
#define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y)) #define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y))
/* Dirk:FIXME:: */
/* Freelists consist of linked cells where the type entry holds the value /* Freelists consist of linked cells where the type entry holds the value
* scm_tc_free_cell and the second entry holds a pointer to the next cell of * scm_tc_free_cell and the second entry holds a pointer to the next cell of
* the freelist. Due to this structure, freelist cells are not cons cells * the freelist. Due to this structure, freelist cells are not cons cells
* and thus may not be accessed using SCM_CAR and SCM_CDR. * and thus may not be accessed using SCM_CAR and SCM_CDR.
*/ */
#define SCM_FREE_CELL_P(x) \
(!SCM_IMP (x) && (* (const scm_bits_t *) SCM2PTR (x) == scm_tc_free_cell))
#define SCM_FREE_CELL_CDR(x) \
(((const scm_bits_t *) SCM2PTR (x)) [1])
#define SCM_SET_FREE_CELL_TYPE(x, v) \
(((scm_bits_t *) SCM2PTR (x)) [0] = (v))
#define SCM_SET_FREE_CELL_CDR(x, v) \
(((scm_bits_t *) SCM2PTR (x)) [1] = (v))
/* the allocated thing: The car of new cells is set to /* the allocated thing: The car of new cells is set to
scm_tc16_allocated to avoid the fragile state of newcells wrt the scm_tc16_allocated to avoid the fragile state of newcells wrt the
gc. If it stays as a freecell, any allocation afterwards could gc. If it stays as a freecell, any allocation afterwards could
@ -174,8 +182,8 @@ typedef scm_cell * SCM_CELLPTR;
else \ else \
{ \ { \
_into = scm_freelist; \ _into = scm_freelist; \
scm_freelist = SCM_CDR (scm_freelist); \ scm_freelist = SCM_FREE_CELL_CDR (scm_freelist); \
SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \ SCM_SET_FREE_CELL_TYPE (_into, scm_tc16_allocated); \
} \ } \
} while(0) } while(0)
#define SCM_NEWCELL2(_into) \ #define SCM_NEWCELL2(_into) \
@ -186,14 +194,14 @@ typedef scm_cell * SCM_CELLPTR;
else \ else \
{ \ { \
_into = scm_freelist2; \ _into = scm_freelist2; \
scm_freelist2 = SCM_CDR (scm_freelist2); \ scm_freelist2 = SCM_FREE_CELL_CDR (scm_freelist2); \
SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \ SCM_SET_FREE_CELL_TYPE (_into, scm_tc16_allocated); \
} \ } \
} while(0) } while(0)
#endif #endif
#define SCM_FREEP(x) (SCM_NIMP (x) && (SCM_CELL_TYPE (x) == scm_tc_free_cell)) #define SCM_FREEP(x) (SCM_FREE_CELL_P (x))
#define SCM_NFREEP(x) (!SCM_FREEP (x)) #define SCM_NFREEP(x) (!SCM_FREEP (x))
/* 1. This shouldn't be used on immediates. /* 1. This shouldn't be used on immediates.