Line data Source code
1 : /*
2 : ** $Id: lgc.c,v 2.38.1.2 2011/03/18 18:05:38 roberto Exp $
3 : ** Garbage Collector
4 : ** See Copyright Notice in lua.h
5 : */
6 :
7 : #include <string.h>
8 :
9 : #define lgc_c
10 : #define LUA_CORE
11 :
12 : #include "lua.h"
13 :
14 : #include "ldebug.h"
15 : #include "ldo.h"
16 : #include "lfunc.h"
17 : #include "lgc.h"
18 : #include "lmem.h"
19 : #include "lobject.h"
20 : #include "lstate.h"
21 : #include "lstring.h"
22 : #include "ltable.h"
23 : #include "ltm.h"
24 :
25 :
26 : #define GCSTEPSIZE 1024u
27 : #define GCSWEEPMAX 40
28 : #define GCSWEEPCOST 10
29 : #define GCFINALIZECOST 100
30 :
31 :
32 : #define maskmarks cast_byte(~(bitmask(BLACKBIT)|WHITEBITS))
33 :
34 : #define makewhite(g,x) \
35 : ((x)->gch.marked = cast_byte(((x)->gch.marked & maskmarks) | luaC_white(g)))
36 :
37 : #define white2gray(x) reset2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT)
38 : #define black2gray(x) resetbit((x)->gch.marked, BLACKBIT)
39 :
40 : #define stringmark(s) reset2bits((s)->tsv.marked, WHITE0BIT, WHITE1BIT)
41 :
42 :
43 : #define isfinalized(u) testbit((u)->marked, FINALIZEDBIT)
44 : #define markfinalized(u) l_setbit((u)->marked, FINALIZEDBIT)
45 :
46 :
47 : #define KEYWEAK bitmask(KEYWEAKBIT)
48 : #define VALUEWEAK bitmask(VALUEWEAKBIT)
49 :
50 :
51 :
52 : #define markvalue(g,o) { checkconsistency(o); \
53 : if (iscollectable(o) && iswhite(gcvalue(o))) reallymarkobject(g,gcvalue(o)); }
54 :
55 : #define markobject(g,t) { if (iswhite(obj2gco(t))) \
56 : reallymarkobject(g, obj2gco(t)); }
57 :
58 :
59 : #define setthreshold(g) (g->GCthreshold = (g->estimate/100) * g->gcpause)
60 :
61 :
62 13366 : static void removeentry (Node *n) {
63 : lua_assert(ttisnil(gval(n)));
64 13366 : if (iscollectable(gkey(n)))
65 0 : setttype(gkey(n), LUA_TDEADKEY); /* dead key; remove it */
66 13366 : }
67 :
68 :
69 66372 : static void reallymarkobject (global_State *g, GCObject *o) {
70 : lua_assert(iswhite(o) && !isdead(g, o));
71 66372 : white2gray(o);
72 66372 : switch (o->gch.tt) {
73 33690 : case LUA_TSTRING: {
74 33690 : return;
75 : }
76 396 : case LUA_TUSERDATA: {
77 396 : Table *mt = gco2u(o)->metatable;
78 396 : gray2black(o); /* udata are never gray */
79 396 : if (mt) markobject(g, mt);
80 396 : markobject(g, gco2u(o)->env);
81 396 : return;
82 : }
83 4596 : case LUA_TUPVAL: {
84 4596 : UpVal *uv = gco2uv(o);
85 4596 : markvalue(g, uv->v);
86 4596 : if (uv->v == &uv->u.value) /* closed? */
87 3583 : gray2black(o); /* open upvalues are never black */
88 4596 : return;
89 : }
90 20971 : case LUA_TFUNCTION: {
91 20971 : gco2cl(o)->c.gclist = g->gray;
92 20971 : g->gray = o;
93 20971 : break;
94 : }
95 3601 : case LUA_TTABLE: {
96 3601 : gco2h(o)->gclist = g->gray;
97 3601 : g->gray = o;
98 3601 : break;
99 : }
100 175 : case LUA_TTHREAD: {
101 175 : gco2th(o)->gclist = g->gray;
102 175 : g->gray = o;
103 175 : break;
104 : }
105 2943 : case LUA_TPROTO: {
106 2943 : gco2p(o)->gclist = g->gray;
107 2943 : g->gray = o;
108 2943 : break;
109 : }
110 : default: lua_assert(0);
111 : }
112 : }
113 :
114 :
115 119 : static void marktmu (global_State *g) {
116 119 : GCObject *u = g->tmudata;
117 119 : if (u) {
118 : do {
119 2 : u = u->gch.next;
120 2 : makewhite(g, u); /* may be marked, if left from previous GC */
121 2 : reallymarkobject(g, u);
122 2 : } while (u != g->tmudata);
123 : }
124 119 : }
125 :
126 :
127 : /* move `dead' udata that need finalization to list `tmudata' */
128 204 : size_t luaC_separateudata (lua_State *L, int all) {
129 204 : global_State *g = G(L);
130 204 : size_t deadmem = 0;
131 204 : GCObject **p = &g->mainthread->next;
132 : GCObject *curr;
133 906 : while ((curr = *p) != NULL) {
134 702 : if (!(iswhite(curr) || all) || isfinalized(gco2u(curr)))
135 365 : p = &curr->gch.next; /* don't bother with them */
136 337 : else if (fasttm(L, gco2u(curr)->metatable, TM_GC) == NULL) {
137 4 : markfinalized(gco2u(curr)); /* don't need finalization */
138 4 : p = &curr->gch.next;
139 : }
140 : else { /* must call its gc method */
141 333 : deadmem += sizeudata(gco2u(curr));
142 333 : markfinalized(gco2u(curr));
143 333 : *p = curr->gch.next;
144 : /* link `curr' at the end of `tmudata' list */
145 333 : if (g->tmudata == NULL) /* list is empty? */
146 76 : g->tmudata = curr->gch.next = curr; /* creates a circular list */
147 : else {
148 257 : curr->gch.next = g->tmudata->gch.next;
149 257 : g->tmudata->gch.next = curr;
150 257 : g->tmudata = curr;
151 : }
152 : }
153 : }
154 204 : return deadmem;
155 : }
156 :
157 :
158 3556 : static int traversetable (global_State *g, Table *h) {
159 : int i;
160 3556 : int weakkey = 0;
161 3556 : int weakvalue = 0;
162 : const TValue *mode;
163 3556 : if (h->metatable)
164 250 : markobject(g, h->metatable);
165 3556 : mode = gfasttm(g, h->metatable, TM_MODE);
166 3556 : if (mode && ttisstring(mode)) { /* is there a weak mode? */
167 243 : weakkey = (strchr(svalue(mode), 'k') != NULL);
168 243 : weakvalue = (strchr(svalue(mode), 'v') != NULL);
169 243 : if (weakkey || weakvalue) { /* is really weak? */
170 243 : h->marked &= ~(KEYWEAK | VALUEWEAK); /* clear bits */
171 243 : h->marked |= cast_byte((weakkey << KEYWEAKBIT) |
172 : (weakvalue << VALUEWEAKBIT));
173 243 : h->gclist = g->weak; /* must be cleared after GC, ... */
174 243 : g->weak = obj2gco(h); /* ... so put in the appropriate list */
175 : }
176 : }
177 3556 : if (weakkey && weakvalue) return 1;
178 3313 : if (!weakvalue) {
179 3313 : i = h->sizearray;
180 4920 : while (i--)
181 1607 : markvalue(g, &h->array[i]);
182 : }
183 3313 : i = sizenode(h);
184 52272 : while (i--) {
185 48959 : Node *n = gnode(h, i);
186 : lua_assert(ttype(gkey(n)) != LUA_TDEADKEY || ttisnil(gval(n)));
187 48959 : if (ttisnil(gval(n)))
188 13366 : removeentry(n); /* remove empty entries */
189 : else {
190 : lua_assert(!ttisnil(gkey(n)));
191 35593 : if (!weakkey) markvalue(g, gkey(n));
192 35593 : if (!weakvalue) markvalue(g, gval(n));
193 : }
194 : }
195 3313 : return weakkey || weakvalue;
196 : }
197 :
198 :
199 : /*
200 : ** All marks are conditional because a GC may happen while the
201 : ** prototype is still being created
202 : */
203 2924 : static void traverseproto (global_State *g, Proto *f) {
204 : int i;
205 2924 : if (f->source) stringmark(f->source);
206 22613 : for (i=0; i<f->sizek; i++) /* mark literals */
207 19689 : markvalue(g, &f->k[i]);
208 6015 : for (i=0; i<f->sizeupvalues; i++) { /* mark upvalue names */
209 3091 : if (f->upvalues[i])
210 3033 : stringmark(f->upvalues[i]);
211 : }
212 5205 : for (i=0; i<f->sizep; i++) { /* mark nested protos */
213 2281 : if (f->p[i])
214 1932 : markobject(g, f->p[i]);
215 : }
216 11978 : for (i=0; i<f->sizelocvars; i++) { /* mark local-variable names */
217 9054 : if (f->locvars[i].varname)
218 8544 : stringmark(f->locvars[i].varname);
219 : }
220 2924 : }
221 :
222 :
223 :
224 20800 : static void traverseclosure (global_State *g, Closure *cl) {
225 20800 : markobject(g, cl->c.env);
226 20800 : if (cl->c.isC) {
227 : int i;
228 19406 : for (i=0; i<cl->c.nupvalues; i++) /* mark its upvalues */
229 386 : markvalue(g, &cl->c.upvalue[i]);
230 : }
231 : else {
232 : int i;
233 : lua_assert(cl->l.nupvalues == cl->l.p->nups);
234 1780 : markobject(g, cl->l.p);
235 8223 : for (i=0; i<cl->l.nupvalues; i++) /* mark its upvalues */
236 6443 : markobject(g, cl->l.upvals[i]);
237 : }
238 20800 : }
239 :
240 :
241 272 : static void checkstacksizes (lua_State *L, StkId max) {
242 272 : int ci_used = cast_int(L->ci - L->base_ci); /* number of `ci' in use */
243 272 : int s_used = cast_int(max - L->stack); /* part of stack in use */
244 272 : if (L->size_ci > LUAI_MAXCALLS) /* handling overflow? */
245 0 : return; /* do not touch the stacks */
246 272 : if (4*ci_used < L->size_ci && 2*BASIC_CI_SIZE < L->size_ci)
247 0 : luaD_reallocCI(L, L->size_ci/2); /* still big enough... */
248 : condhardstacktests(luaD_reallocCI(L, ci_used + 1));
249 272 : if (4*s_used < L->stacksize &&
250 0 : 2*(BASIC_STACK_SIZE+EXTRA_STACK) < L->stacksize)
251 0 : luaD_reallocstack(L, L->stacksize/2); /* still big enough... */
252 : condhardstacktests(luaD_reallocstack(L, s_used));
253 : }
254 :
255 :
256 272 : static void traversestack (global_State *g, lua_State *l) {
257 : StkId o, lim;
258 : CallInfo *ci;
259 272 : markvalue(g, gt(l));
260 272 : lim = l->top;
261 1731 : for (ci = l->base_ci; ci <= l->ci; ci++) {
262 : lua_assert(ci->top <= l->stack_last);
263 1459 : if (lim < ci->top) lim = ci->top;
264 : }
265 8551 : for (o = l->stack; o < l->top; o++)
266 8279 : markvalue(g, o);
267 4174 : for (; o <= lim; o++)
268 3902 : setnilvalue(o);
269 272 : checkstacksizes(l, lim);
270 272 : }
271 :
272 :
273 : /*
274 : ** traverse one gray object, turning it to black.
275 : ** Returns `quantity' traversed.
276 : */
277 27552 : static l_mem propagatemark (global_State *g) {
278 27552 : GCObject *o = g->gray;
279 : lua_assert(isgray(o));
280 27552 : gray2black(o);
281 27552 : switch (o->gch.tt) {
282 3556 : case LUA_TTABLE: {
283 3556 : Table *h = gco2h(o);
284 3556 : g->gray = h->gclist;
285 3556 : if (traversetable(g, h)) /* table is weak? */
286 243 : black2gray(o); /* keep it gray */
287 3556 : return sizeof(Table) + sizeof(TValue) * h->sizearray +
288 3556 : sizeof(Node) * sizenode(h);
289 : }
290 20800 : case LUA_TFUNCTION: {
291 20800 : Closure *cl = gco2cl(o);
292 20800 : g->gray = cl->c.gclist;
293 20800 : traverseclosure(g, cl);
294 22580 : return (cl->c.isC) ? sizeCclosure(cl->c.nupvalues) :
295 1780 : sizeLclosure(cl->l.nupvalues);
296 : }
297 272 : case LUA_TTHREAD: {
298 272 : lua_State *th = gco2th(o);
299 272 : g->gray = th->gclist;
300 272 : th->gclist = g->grayagain;
301 272 : g->grayagain = o;
302 272 : black2gray(o);
303 272 : traversestack(g, th);
304 272 : return sizeof(lua_State) + sizeof(TValue) * th->stacksize +
305 272 : sizeof(CallInfo) * th->size_ci;
306 : }
307 2924 : case LUA_TPROTO: {
308 2924 : Proto *p = gco2p(o);
309 2924 : g->gray = p->gclist;
310 2924 : traverseproto(g, p);
311 2924 : return sizeof(Proto) + sizeof(Instruction) * p->sizecode +
312 2924 : sizeof(Proto *) * p->sizep +
313 2924 : sizeof(TValue) * p->sizek +
314 2924 : sizeof(int) * p->sizelineinfo +
315 2924 : sizeof(LocVar) * p->sizelocvars +
316 2924 : sizeof(TString *) * p->sizeupvalues;
317 : }
318 0 : default: lua_assert(0); return 0;
319 : }
320 : }
321 :
322 :
323 476 : static size_t propagateall (global_State *g) {
324 476 : size_t m = 0;
325 1174 : while (g->gray) m += propagatemark(g);
326 476 : return m;
327 : }
328 :
329 :
330 : /*
331 : ** The next function tells whether a key or value can be cleared from
332 : ** a weak table. Non-collectable objects are never removed from weak
333 : ** tables. Strings behave as `values', so are never removed too. for
334 : ** other objects: if really collected, cannot keep them; for userdata
335 : ** being finalized, keep them in keys, but not in values
336 : */
337 238 : static int iscleared (const TValue *o, int iskey) {
338 238 : if (!iscollectable(o)) return 0;
339 238 : if (ttisstring(o)) {
340 238 : stringmark(rawtsvalue(o)); /* strings are `values', so are never weak */
341 238 : return 0;
342 : }
343 0 : return iswhite(gcvalue(o)) ||
344 0 : (ttisuserdata(o) && (!iskey && isfinalized(uvalue(o))));
345 : }
346 :
347 :
348 : /*
349 : ** clear collected entries from weaktables
350 : */
351 119 : static void cleartable (GCObject *l) {
352 238 : while (l) {
353 119 : Table *h = gco2h(l);
354 119 : int i = h->sizearray;
355 : lua_assert(testbit(h->marked, VALUEWEAKBIT) ||
356 : testbit(h->marked, KEYWEAKBIT));
357 119 : if (testbit(h->marked, VALUEWEAKBIT)) {
358 119 : while (i--) {
359 0 : TValue *o = &h->array[i];
360 0 : if (iscleared(o, 0)) /* value was collected? */
361 0 : setnilvalue(o); /* remove value */
362 : }
363 : }
364 119 : i = sizenode(h);
365 238 : while (i--) {
366 119 : Node *n = gnode(h, i);
367 238 : if (!ttisnil(gval(n)) && /* non-empty entry? */
368 238 : (iscleared(key2tval(n), 1) || iscleared(gval(n), 0))) {
369 0 : setnilvalue(gval(n)); /* remove value ... */
370 0 : removeentry(n); /* remove entry from table */
371 : }
372 : }
373 119 : l = h->gclist;
374 : }
375 119 : }
376 :
377 :
378 72351 : static void freeobj (lua_State *L, GCObject *o) {
379 72351 : switch (o->gch.tt) {
380 2006 : case LUA_TPROTO: luaF_freeproto(L, gco2p(o)); break;
381 14734 : case LUA_TFUNCTION: luaF_freeclosure(L, gco2cl(o)); break;
382 5582 : case LUA_TUPVAL: luaF_freeupval(L, gco2uv(o)); break;
383 10286 : case LUA_TTABLE: luaH_free(L, gco2h(o)); break;
384 24 : case LUA_TTHREAD: {
385 : lua_assert(gco2th(o) != L && gco2th(o) != G(L)->mainthread);
386 24 : luaE_freethread(L, gco2th(o));
387 24 : break;
388 : }
389 39382 : case LUA_TSTRING: {
390 39382 : G(L)->strt.nuse--;
391 39382 : luaM_freemem(L, o, sizestring(gco2ts(o)));
392 39382 : break;
393 : }
394 337 : case LUA_TUSERDATA: {
395 337 : luaM_freemem(L, o, sizeudata(gco2u(o)));
396 337 : break;
397 : }
398 72351 : default: lua_assert(0);
399 : }
400 72351 : }
401 :
402 :
403 :
404 : #define sweepwholelist(L,p) sweeplist(L,p,MAX_LUMEM)
405 :
406 :
407 109336 : static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
408 : GCObject *curr;
409 109336 : global_State *g = G(L);
410 109336 : int deadmask = otherwhite(g);
411 251965 : while ((curr = *p) != NULL && count-- > 0) {
412 142629 : if (curr->gch.tt == LUA_TTHREAD) /* sweep open upvalues of each thread */
413 245 : sweepwholelist(L, &gco2th(curr)->openupval);
414 142629 : if ((curr->gch.marked ^ WHITEBITS) & deadmask) { /* not dead? */
415 : lua_assert(!isdead(g, curr) || testbit(curr->gch.marked, FIXEDBIT));
416 70278 : makewhite(g, curr); /* make it white (for next cycle) */
417 70278 : p = &curr->gch.next;
418 : }
419 : else { /* must erase `curr' */
420 : lua_assert(isdead(g, curr) || deadmask == bitmask(SFIXEDBIT));
421 72351 : *p = curr->gch.next;
422 72351 : if (curr == g->rootgc) /* is the first element of the list? */
423 0 : g->rootgc = curr->gch.next; /* adjust first */
424 72351 : freeobj(L, curr);
425 : }
426 : }
427 109336 : return p;
428 : }
429 :
430 :
431 122 : static void checkSizes (lua_State *L) {
432 122 : global_State *g = G(L);
433 : /* check size of string hash */
434 122 : if (g->strt.nuse < cast(lu_int32, g->strt.size/4) &&
435 0 : g->strt.size > MINSTRTABSIZE*2)
436 0 : luaS_resize(L, g->strt.size/2); /* table is too big */
437 : /* check size of buffer */
438 122 : if (luaZ_sizebuffer(&g->buff) > LUA_MINBUFFER*2) { /* buffer too big? */
439 35 : size_t newsize = luaZ_sizebuffer(&g->buff) / 2;
440 35 : luaZ_resizebuffer(L, &g->buff, newsize);
441 : }
442 122 : }
443 :
444 :
445 333 : static void GCTM (lua_State *L) {
446 333 : global_State *g = G(L);
447 333 : GCObject *o = g->tmudata->gch.next; /* get first element */
448 333 : Udata *udata = rawgco2u(o);
449 : const TValue *tm;
450 : /* remove udata from `tmudata' */
451 333 : if (o == g->tmudata) /* last element? */
452 76 : g->tmudata = NULL;
453 : else
454 257 : g->tmudata->gch.next = udata->uv.next;
455 333 : udata->uv.next = g->mainthread->next; /* return it to `root' list */
456 333 : g->mainthread->next = o;
457 333 : makewhite(g, o);
458 333 : tm = fasttm(L, udata->uv.metatable, TM_GC);
459 333 : if (tm != NULL) {
460 333 : lu_byte oldah = L->allowhook;
461 333 : lu_mem oldt = g->GCthreshold;
462 333 : L->allowhook = 0; /* stop debug hooks during GC tag method */
463 333 : g->GCthreshold = 2*g->totalbytes; /* avoid GC steps */
464 333 : setobj2s(L, L->top, tm);
465 333 : setuvalue(L, L->top+1, udata);
466 333 : L->top += 2;
467 333 : luaD_call(L, L->top - 2, 0);
468 333 : L->allowhook = oldah; /* restore hooks */
469 333 : g->GCthreshold = oldt; /* restore threshold */
470 : }
471 333 : }
472 :
473 :
474 : /*
475 : ** Call all GC tag methods
476 : */
477 85 : void luaC_callGCTM (lua_State *L) {
478 416 : while (G(L)->tmudata)
479 331 : GCTM(L);
480 85 : }
481 :
482 :
483 85 : void luaC_freeall (lua_State *L) {
484 85 : global_State *g = G(L);
485 : int i;
486 85 : g->currentwhite = WHITEBITS | bitmask(SFIXEDBIT); /* mask to collect all elements */
487 85 : sweepwholelist(L, &g->rootgc);
488 43285 : for (i = 0; i < g->strt.size; i++) /* free all string lists */
489 43200 : sweepwholelist(L, &g->strt.hash[i]);
490 85 : }
491 :
492 :
493 279 : static void markmt (global_State *g) {
494 : int i;
495 2790 : for (i=0; i<NUM_TAGS; i++)
496 2511 : if (g->mt[i]) markobject(g, g->mt[i]);
497 279 : }
498 :
499 :
500 : /* mark root set */
501 160 : static void markroot (lua_State *L) {
502 160 : global_State *g = G(L);
503 160 : g->gray = NULL;
504 160 : g->grayagain = NULL;
505 160 : g->weak = NULL;
506 160 : markobject(g, g->mainthread);
507 : /* make global table be traversed before main stack */
508 160 : markvalue(g, gt(g->mainthread));
509 160 : markvalue(g, registry(L));
510 160 : markmt(g);
511 160 : g->gcstate = GCSpropagate;
512 160 : }
513 :
514 :
515 119 : static void remarkupvals (global_State *g) {
516 : UpVal *uv;
517 1132 : for (uv = g->uvhead.u.l.next; uv != &g->uvhead; uv = uv->u.l.next) {
518 : lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
519 1013 : if (isgray(obj2gco(uv)))
520 878 : markvalue(g, uv->v);
521 : }
522 119 : }
523 :
524 :
525 119 : static void atomic (lua_State *L) {
526 119 : global_State *g = G(L);
527 : size_t udsize; /* total size of userdata to be finalized */
528 : /* remark occasional upvalues of (maybe) dead threads */
529 119 : remarkupvals(g);
530 : /* traverse objects cautch by write barrier and by 'remarkupvals' */
531 119 : propagateall(g);
532 : /* remark weak tables */
533 119 : g->gray = g->weak;
534 119 : g->weak = NULL;
535 : lua_assert(!iswhite(obj2gco(g->mainthread)));
536 119 : markobject(g, L); /* mark running thread */
537 119 : markmt(g); /* mark basic metatables (again) */
538 119 : propagateall(g);
539 : /* remark gray again */
540 119 : g->gray = g->grayagain;
541 119 : g->grayagain = NULL;
542 119 : propagateall(g);
543 119 : udsize = luaC_separateudata(L, 0); /* separate userdata to be finalized */
544 119 : marktmu(g); /* mark `preserved' userdata */
545 119 : udsize += propagateall(g); /* remark, to propagate `preserveness' */
546 119 : cleartable(g->weak); /* remove collected objects from weak tables */
547 : /* flip current white */
548 119 : g->currentwhite = cast_byte(otherwhite(g));
549 119 : g->sweepstrgc = 0;
550 119 : g->sweepgc = &g->rootgc;
551 119 : g->gcstate = GCSsweepstring;
552 119 : g->estimate = g->totalbytes - udsize; /* first estimate */
553 119 : }
554 :
555 :
556 93053 : static l_mem singlestep (lua_State *L) {
557 93053 : global_State *g = G(L);
558 : /*lua_checkmemory(L);*/
559 93053 : switch (g->gcstate) {
560 155 : case GCSpause: {
561 155 : markroot(L); /* start a new collection */
562 155 : return 0;
563 : }
564 26973 : case GCSpropagate: {
565 26973 : if (g->gray)
566 26854 : return propagatemark(g);
567 : else { /* no more `gray' objects */
568 119 : atomic(L); /* finish mark phase */
569 119 : return 0;
570 : }
571 : }
572 64768 : case GCSsweepstring: {
573 64768 : lu_mem old = g->totalbytes;
574 64768 : sweepwholelist(L, &g->strt.hash[g->sweepstrgc++]);
575 64768 : if (g->sweepstrgc >= g->strt.size) /* nothing more to sweep? */
576 123 : g->gcstate = GCSsweep; /* end sweep-string phase */
577 : lua_assert(old >= g->totalbytes);
578 64768 : g->estimate -= old - g->totalbytes;
579 64768 : return GCSWEEPCOST;
580 : }
581 1038 : case GCSsweep: {
582 1038 : lu_mem old = g->totalbytes;
583 1038 : g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
584 1038 : if (*g->sweepgc == NULL) { /* nothing more to sweep? */
585 122 : checkSizes(L);
586 122 : g->gcstate = GCSfinalize; /* end sweep phase */
587 : }
588 : lua_assert(old >= g->totalbytes);
589 1038 : g->estimate -= old - g->totalbytes;
590 1038 : return GCSWEEPMAX*GCSWEEPCOST;
591 : }
592 119 : case GCSfinalize: {
593 119 : if (g->tmudata) {
594 2 : GCTM(L);
595 2 : if (g->estimate > GCFINALIZECOST)
596 2 : g->estimate -= GCFINALIZECOST;
597 2 : return GCFINALIZECOST;
598 : }
599 : else {
600 117 : g->gcstate = GCSpause; /* end collection */
601 117 : g->gcdept = 0;
602 117 : return 0;
603 : }
604 : }
605 0 : default: lua_assert(0); return 0;
606 : }
607 : }
608 :
609 :
610 2099 : void luaC_step (lua_State *L) {
611 2099 : global_State *g = G(L);
612 2099 : l_mem lim = (GCSTEPSIZE/100) * g->gcstepmul;
613 2099 : if (lim == 0)
614 0 : lim = (MAX_LUMEM-1)/2; /* no limit */
615 2099 : g->gcdept += g->totalbytes - g->GCthreshold;
616 : do {
617 87316 : lim -= singlestep(L);
618 87316 : if (g->gcstate == GCSpause)
619 112 : break;
620 87204 : } while (lim > 0);
621 2099 : if (g->gcstate != GCSpause) {
622 1987 : if (g->gcdept < GCSTEPSIZE)
623 1669 : g->GCthreshold = g->totalbytes + GCSTEPSIZE; /* - lim/g->gcstepmul;*/
624 : else {
625 318 : g->gcdept -= GCSTEPSIZE;
626 318 : g->GCthreshold = g->totalbytes;
627 : }
628 : }
629 : else {
630 112 : setthreshold(g);
631 : }
632 2099 : }
633 :
634 :
635 5 : void luaC_fullgc (lua_State *L) {
636 5 : global_State *g = G(L);
637 5 : if (g->gcstate <= GCSpropagate) {
638 : /* reset sweep marks to sweep all elements (returning them to white) */
639 4 : g->sweepstrgc = 0;
640 4 : g->sweepgc = &g->rootgc;
641 : /* reset other collector lists */
642 4 : g->gray = NULL;
643 4 : g->grayagain = NULL;
644 4 : g->weak = NULL;
645 4 : g->gcstate = GCSsweepstring;
646 : }
647 : lua_assert(g->gcstate != GCSpause && g->gcstate != GCSpropagate);
648 : /* finish any pending sweep phase */
649 1829 : while (g->gcstate != GCSfinalize) {
650 : lua_assert(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep);
651 1824 : singlestep(L);
652 : }
653 5 : markroot(L);
654 3918 : while (g->gcstate != GCSpause) {
655 3913 : singlestep(L);
656 : }
657 5 : setthreshold(g);
658 5 : }
659 :
660 :
661 677 : void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v) {
662 677 : global_State *g = G(L);
663 : lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
664 : lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
665 : lua_assert(ttype(&o->gch) != LUA_TTABLE);
666 : /* must keep invariant? */
667 677 : if (g->gcstate == GCSpropagate)
668 579 : reallymarkobject(g, v); /* restore invariant */
669 : else /* don't mind */
670 98 : makewhite(g, o); /* mark as white just to avoid other barriers */
671 677 : }
672 :
673 :
674 283 : void luaC_barrierback (lua_State *L, Table *t) {
675 283 : global_State *g = G(L);
676 283 : GCObject *o = obj2gco(t);
677 : lua_assert(isblack(o) && !isdead(g, o));
678 : lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
679 283 : black2gray(o); /* make table gray (again) */
680 283 : t->gclist = g->grayagain;
681 283 : g->grayagain = o;
682 283 : }
683 :
684 :
685 29019 : void luaC_link (lua_State *L, GCObject *o, lu_byte tt) {
686 29019 : global_State *g = G(L);
687 29019 : o->gch.next = g->rootgc;
688 29019 : g->rootgc = o;
689 29019 : o->gch.marked = luaC_white(g);
690 29019 : o->gch.tt = tt;
691 29019 : }
692 :
693 :
694 5708 : void luaC_linkupval (lua_State *L, UpVal *uv) {
695 5708 : global_State *g = G(L);
696 5708 : GCObject *o = obj2gco(uv);
697 5708 : o->gch.next = g->rootgc; /* link upvalue into `rootgc' list */
698 5708 : g->rootgc = o;
699 5708 : if (isgray(o)) {
700 290 : if (g->gcstate == GCSpropagate) {
701 1 : gray2black(o); /* closed upvalues need barrier */
702 1 : luaC_barrier(L, uv, uv->v);
703 : }
704 : else { /* sweep phase: sweep it (turning it into white) */
705 289 : makewhite(g, o);
706 : lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
707 : }
708 : }
709 5708 : }
710 :
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