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cleaner code for manipulation of `marked' field

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This commit is contained in:
Roberto Ierusalimschy
2003-11-17 17:50:05 -02:00
parent 921b1723e2
commit ab7d9bfd0c
5 changed files with 69 additions and 46 deletions
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70
lgc.c
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@@ -1,5 +1,5 @@
/*
** $Id: lgc.c,v 1.176 2003/07/29 19:25:37 roberto Exp roberto $
** $Id: lgc.c,v 1.177 2003/08/27 21:01:44 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -29,45 +29,38 @@ typedef struct GCState {
} GCState;
/*
** some userful bit tricks
*/
#define setbit(x,b) ((x) |= (1<<(b)))
#define resetbit(x,b) ((x) &= cast(lu_byte, ~(1<<(b))))
#define testbit(x,b) ((x) & (1<<(b)))
#define unmark(x) resetbit((x)->gch.marked, 0)
#define ismarked(x) ((x)->gch.marked & ((1<<4)|1))
#define unblack(x) resetbit((x)->gch.marked, BLACKBIT)
#define isblack(x) testbit((x)->gch.marked, BLACKBIT)
#define blacken(x) setbit((x)->gch.marked, BLACKBIT)
#define stringmark(s) setbit((s)->tsv.marked, 0)
#define stringmark(s) setbit((s)->tsv.marked, BLACKBIT)
#define isfinalized(u) (!testbit((u)->uv.marked, 1))
#define markfinalized(u) resetbit((u)->uv.marked, 1)
#define isfinalized(u) testbit((u)->uv.marked, FINALIZEDBIT)
#define markfinalized(u) setbit((u)->uv.marked, FINALIZEDBIT)
#define KEYWEAKBIT 1
#define VALUEWEAKBIT 2
#define KEYWEAK (1<<KEYWEAKBIT)
#define VALUEWEAK (1<<VALUEWEAKBIT)
#define KEYWEAK bitmask(KEYWEAKBIT)
#define VALUEWEAK bitmask(VALUEWEAKBIT)
#define markobject(st,o) { checkconsistency(o); \
if (iscollectable(o) && !ismarked(gcvalue(o))) reallymarkobject(st,gcvalue(o)); }
if (iscollectable(o) && !isblack(gcvalue(o))) reallymarkobject(st,gcvalue(o)); }
#define condmarkobject(st,o,c) { checkconsistency(o); \
if (iscollectable(o) && !ismarked(gcvalue(o)) && (c)) \
if (iscollectable(o) && !isblack(gcvalue(o)) && (c)) \
reallymarkobject(st,gcvalue(o)); }
#define markvalue(st,t) { if (!ismarked(valtogco(t))) \
#define markvalue(st,t) { if (!isblack(valtogco(t))) \
reallymarkobject(st, valtogco(t)); }
static void reallymarkobject (GCState *st, GCObject *o) {
lua_assert(!ismarked(o));
setbit(o->gch.marked, 0); /* mark object */
lua_assert(!isblack(o));
blacken(o);
switch (o->gch.tt) {
case LUA_TUSERDATA: {
markvalue(st, gcotou(o)->uv.metatable);
@@ -101,7 +94,7 @@ static void reallymarkobject (GCState *st, GCObject *o) {
static void marktmu (GCState *st) {
GCObject *u;
for (u = st->g->tmudata; u; u = u->gch.next) {
unmark(u); /* may be marked, if left from previous GC */
unblack(u); /* may be marked, if left from previous GC */
reallymarkobject(st, u);
}
}
@@ -116,7 +109,7 @@ size_t luaC_separateudata (lua_State *L) {
GCObject **lastcollected = &collected;
while ((curr = *p) != NULL) {
lua_assert(curr->gch.tt == LUA_TUSERDATA);
if (ismarked(curr) || isfinalized(gcotou(curr)))
if (isblack(curr) || isfinalized(gcotou(curr)))
p = &curr->gch.next; /* don't bother with them */
else if (fasttm(L, gcotou(curr)->uv.metatable, TM_GC) == NULL) {
@@ -216,9 +209,9 @@ static void traverseclosure (GCState *st, Closure *cl) {
markvalue(st, cl->l.p);
for (i=0; i<cl->l.nupvalues; i++) { /* mark its upvalues */
UpVal *u = cl->l.upvals[i];
if (!u->marked) {
if (!isblack(valtogco(u))) {
blacken(valtogco(u));
markobject(st, &u->value);
u->marked = 1;
}
}
}
@@ -300,7 +293,7 @@ static int iscleared (const TObject *o, int iskey) {
stringmark(tsvalue(o)); /* strings are `values', so are never weak */
return 0;
}
return !ismarked(gcvalue(o)) ||
return !isblack(gcvalue(o)) ||
(ttisuserdata(o) && (!iskey && isfinalized(uvalue(o))));
}
@@ -319,8 +312,9 @@ static void cleartable (GCObject *l) {
while (l) {
Table *h = gcotoh(l);
int i = h->sizearray;
lua_assert(h->marked & (KEYWEAK | VALUEWEAK));
if (h->marked & VALUEWEAK) {
lua_assert(testbit(h->marked, VALUEWEAKBIT) ||
testbit(h->marked, KEYWEAKBIT));
if (testbit(h->marked, VALUEWEAKBIT)) {
while (i--) {
TObject *o = &h->array[i];
if (iscleared(o, 0)) /* value was collected? */
@@ -363,12 +357,12 @@ static void freeobj (lua_State *L, GCObject *o) {
}
static int sweeplist (lua_State *L, GCObject **p, int limit) {
static int sweeplist (lua_State *L, GCObject **p, int mask) {
GCObject *curr;
int count = 0; /* number of collected items */
while ((curr = *p) != NULL) {
if (curr->gch.marked > limit) {
unmark(curr);
if (curr->gch.marked & mask) {
unblack(curr);
p = &curr->gch.next;
}
else {
@@ -381,10 +375,10 @@ static int sweeplist (lua_State *L, GCObject **p, int limit) {
}
static void sweepstrings (lua_State *L, int all) {
static void sweepstrings (lua_State *L, int mask) {
int i;
for (i=0; i<G(L)->strt.size; i++) { /* for each list */
G(L)->strt.nuse -= sweeplist(L, &G(L)->strt.hash[i], all);
G(L)->strt.nuse -= sweeplist(L, &G(L)->strt.hash[i], mask);
}
}
@@ -426,7 +420,7 @@ void luaC_callGCTM (lua_State *L) {
udata->uv.next = G(L)->rootudata; /* return it to `root' list */
G(L)->rootudata = o;
setuvalue(L->top - 1, udata); /* keep a reference to it */
unmark(o);
unblack(o);
do1gcTM(L, udata);
}
L->top--;
@@ -435,10 +429,10 @@ void luaC_callGCTM (lua_State *L) {
void luaC_sweep (lua_State *L, int all) {
if (all) all = 256; /* larger than any mark */
sweeplist(L, &G(L)->rootudata, all);
sweepstrings(L, all);
sweeplist(L, &G(L)->rootgc, all);
int mask = (all) ? 0 : (bitmask(BLACKBIT) | bitmask(FIXEDBIT));
sweeplist(L, &G(L)->rootudata, mask);
sweepstrings(L, mask);
sweeplist(L, &G(L)->rootgc, mask);
}