lgc.c 21 KB

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  1. /*
  2. ** $Id: lgc.c,v 2.38.1.1 2007/12/27 13:02:25 roberto Exp $
  3. ** Garbage Collector
  4. ** See Copyright Notice in lua.h
  5. */
  6. #define lgc_c
  7. #define LUA_CORE
  8. #define LUAC_CROSS_FILE
  9. #include "lua.h"
  10. #include C_HEADER_STRING
  11. #include "ldebug.h"
  12. #include "ldo.h"
  13. #include "lfunc.h"
  14. #include "lgc.h"
  15. #include "lmem.h"
  16. #include "lobject.h"
  17. #include "lstate.h"
  18. #include "lstring.h"
  19. #include "ltable.h"
  20. #include "ltm.h"
  21. #include "lrotable.h"
  22. #define GCSTEPSIZE 1024u
  23. #define GCSWEEPMAX 40
  24. #define GCSWEEPCOST 10
  25. #define GCFINALIZECOST 100
  26. #define maskmarks cast_byte(~(bitmask(BLACKBIT)|WHITEBITS))
  27. #define makewhite(g,x) \
  28. ((x)->gch.marked = cast_byte(((x)->gch.marked & maskmarks) | luaC_white(g)))
  29. #define white2gray(x) reset2bits((x)->gch.marked, WHITE0BIT, WHITE1BIT)
  30. #define black2gray(x) resetbit((x)->gch.marked, BLACKBIT)
  31. #define stringmark(s) reset2bits((s)->tsv.marked, WHITE0BIT, WHITE1BIT)
  32. #define isfinalized(u) testbit((u)->marked, FINALIZEDBIT)
  33. #define markfinalized(u) l_setbit((u)->marked, FINALIZEDBIT)
  34. #define KEYWEAK bitmask(KEYWEAKBIT)
  35. #define VALUEWEAK bitmask(VALUEWEAKBIT)
  36. #define markvalue(g,o) { checkconsistency(o); \
  37. if (iscollectable(o) && iswhite(gcvalue(o))) reallymarkobject(g,gcvalue(o)); }
  38. #define markobject(g,t) { if (iswhite(obj2gco(t))) \
  39. reallymarkobject(g, obj2gco(t)); }
  40. #define setthreshold(g) (g->GCthreshold = (g->estimate/100) * g->gcpause)
  41. static void removeentry (Node *n) {
  42. lua_assert(ttisnil(gval(n)));
  43. if (iscollectable(gkey(n)))
  44. setttype(gkey(n), LUA_TDEADKEY); /* dead key; remove it */
  45. }
  46. static void reallymarkobject (global_State *g, GCObject *o) {
  47. lua_assert(iswhite(o) && !isdead(g, o));
  48. white2gray(o);
  49. switch (o->gch.tt) {
  50. case LUA_TSTRING: {
  51. return;
  52. }
  53. case LUA_TUSERDATA: {
  54. Table *mt = gco2u(o)->metatable;
  55. gray2black(o); /* udata are never gray */
  56. if (mt && !luaR_isrotable(mt)) markobject(g, mt);
  57. markobject(g, gco2u(o)->env);
  58. return;
  59. }
  60. case LUA_TUPVAL: {
  61. UpVal *uv = gco2uv(o);
  62. markvalue(g, uv->v);
  63. if (uv->v == &uv->u.value) /* closed? */
  64. gray2black(o); /* open upvalues are never black */
  65. return;
  66. }
  67. case LUA_TFUNCTION: {
  68. gco2cl(o)->c.gclist = g->gray;
  69. g->gray = o;
  70. break;
  71. }
  72. case LUA_TTABLE: {
  73. gco2h(o)->gclist = g->gray;
  74. g->gray = o;
  75. break;
  76. }
  77. case LUA_TTHREAD: {
  78. gco2th(o)->gclist = g->gray;
  79. g->gray = o;
  80. break;
  81. }
  82. case LUA_TPROTO: {
  83. gco2p(o)->gclist = g->gray;
  84. g->gray = o;
  85. break;
  86. }
  87. default: lua_assert(0);
  88. }
  89. }
  90. static void marktmu (global_State *g) {
  91. GCObject *u = g->tmudata;
  92. if (u) {
  93. do {
  94. u = u->gch.next;
  95. makewhite(g, u); /* may be marked, if left from previous GC */
  96. reallymarkobject(g, u);
  97. } while (u != g->tmudata);
  98. }
  99. }
  100. /* move `dead' udata that need finalization to list `tmudata' */
  101. size_t luaC_separateudata (lua_State *L, int all) {
  102. global_State *g = G(L);
  103. size_t deadmem = 0;
  104. GCObject **p = &g->mainthread->next;
  105. GCObject *curr;
  106. while ((curr = *p) != NULL) {
  107. if (!(iswhite(curr) || all) || isfinalized(gco2u(curr)))
  108. p = &curr->gch.next; /* don't bother with them */
  109. else if (fasttm(L, gco2u(curr)->metatable, TM_GC) == NULL) {
  110. markfinalized(gco2u(curr)); /* don't need finalization */
  111. p = &curr->gch.next;
  112. }
  113. else { /* must call its gc method */
  114. deadmem += sizeudata(gco2u(curr));
  115. markfinalized(gco2u(curr));
  116. *p = curr->gch.next;
  117. /* link `curr' at the end of `tmudata' list */
  118. if (g->tmudata == NULL) /* list is empty? */
  119. g->tmudata = curr->gch.next = curr; /* creates a circular list */
  120. else {
  121. curr->gch.next = g->tmudata->gch.next;
  122. g->tmudata->gch.next = curr;
  123. g->tmudata = curr;
  124. }
  125. }
  126. }
  127. return deadmem;
  128. }
  129. static int traversetable (global_State *g, Table *h) {
  130. int i;
  131. int weakkey = 0;
  132. int weakvalue = 0;
  133. const TValue *mode;
  134. if (h->metatable && !luaR_isrotable(h->metatable))
  135. markobject(g, h->metatable);
  136. mode = gfasttm(g, h->metatable, TM_MODE);
  137. if (mode && ttisstring(mode)) { /* is there a weak mode? */
  138. weakkey = (c_strchr(svalue(mode), 'k') != NULL);
  139. weakvalue = (c_strchr(svalue(mode), 'v') != NULL);
  140. if (weakkey || weakvalue) { /* is really weak? */
  141. h->marked &= ~(KEYWEAK | VALUEWEAK); /* clear bits */
  142. h->marked |= cast_byte((weakkey << KEYWEAKBIT) |
  143. (weakvalue << VALUEWEAKBIT));
  144. h->gclist = g->weak; /* must be cleared after GC, ... */
  145. g->weak = obj2gco(h); /* ... so put in the appropriate list */
  146. }
  147. }
  148. if (weakkey && weakvalue) return 1;
  149. if (!weakvalue) {
  150. i = h->sizearray;
  151. while (i--)
  152. markvalue(g, &h->array[i]);
  153. }
  154. i = sizenode(h);
  155. while (i--) {
  156. Node *n = gnode(h, i);
  157. lua_assert(ttype(gkey(n)) != LUA_TDEADKEY || ttisnil(gval(n)));
  158. if (ttisnil(gval(n)))
  159. removeentry(n); /* remove empty entries */
  160. else {
  161. lua_assert(!ttisnil(gkey(n)));
  162. if (!weakkey) markvalue(g, gkey(n));
  163. if (!weakvalue) markvalue(g, gval(n));
  164. }
  165. }
  166. return weakkey || weakvalue;
  167. }
  168. /*
  169. ** All marks are conditional because a GC may happen while the
  170. ** prototype is still being created
  171. */
  172. static void traverseproto (global_State *g, Proto *f) {
  173. int i;
  174. if (f->source) stringmark(f->source);
  175. for (i=0; i<f->sizek; i++) /* mark literals */
  176. markvalue(g, &f->k[i]);
  177. for (i=0; i<f->sizeupvalues; i++) { /* mark upvalue names */
  178. if (f->upvalues[i])
  179. stringmark(f->upvalues[i]);
  180. }
  181. for (i=0; i<f->sizep; i++) { /* mark nested protos */
  182. if (f->p[i])
  183. markobject(g, f->p[i]);
  184. }
  185. for (i=0; i<f->sizelocvars; i++) { /* mark local-variable names */
  186. if (f->locvars[i].varname)
  187. stringmark(f->locvars[i].varname);
  188. }
  189. }
  190. static void traverseclosure (global_State *g, Closure *cl) {
  191. markobject(g, cl->c.env);
  192. if (cl->c.isC) {
  193. int i;
  194. for (i=0; i<cl->c.nupvalues; i++) /* mark its upvalues */
  195. markvalue(g, &cl->c.upvalue[i]);
  196. }
  197. else {
  198. int i;
  199. lua_assert(cl->l.nupvalues == cl->l.p->nups);
  200. markobject(g, cl->l.p);
  201. for (i=0; i<cl->l.nupvalues; i++) { /* mark its upvalues */
  202. if(cl->l.upvals[i])
  203. markobject(g, cl->l.upvals[i]);
  204. }
  205. }
  206. }
  207. static void checkstacksizes (lua_State *L, StkId max) {
  208. int ci_used = cast_int(L->ci - L->base_ci); /* number of `ci' in use */
  209. int s_used = cast_int(max - L->stack); /* part of stack in use */
  210. if (L->size_ci > LUAI_MAXCALLS) /* handling overflow? */
  211. return; /* do not touch the stacks */
  212. if (4*ci_used < L->size_ci && 2*BASIC_CI_SIZE < L->size_ci)
  213. luaD_reallocCI(L, L->size_ci/2); /* still big enough... */
  214. condhardstacktests(luaD_reallocCI(L, ci_used + 1));
  215. if (4*s_used < L->stacksize &&
  216. 2*(BASIC_STACK_SIZE+EXTRA_STACK) < L->stacksize)
  217. luaD_reallocstack(L, L->stacksize/2); /* still big enough... */
  218. condhardstacktests(luaD_reallocstack(L, s_used));
  219. }
  220. static void traversestack (global_State *g, lua_State *l) {
  221. StkId o, lim;
  222. CallInfo *ci;
  223. markvalue(g, gt(l));
  224. lim = l->top;
  225. if(l->stack == NULL) return; /* no stack to traverse */
  226. for (ci = l->base_ci; ci <= l->ci; ci++) {
  227. lua_assert(ci->top <= l->stack_last);
  228. if (lim < ci->top) lim = ci->top;
  229. }
  230. for (o = l->stack; o < l->top; o++)
  231. markvalue(g, o);
  232. for (; o <= lim; o++)
  233. setnilvalue(o);
  234. if (!isfixedstack(l)) /* if stack size is fixed, can't resize it. */
  235. checkstacksizes(l, lim);
  236. }
  237. /*
  238. ** traverse one gray object, turning it to black.
  239. ** Returns `quantity' traversed.
  240. */
  241. static l_mem propagatemark (global_State *g) {
  242. GCObject *o = g->gray;
  243. lua_assert(isgray(o));
  244. gray2black(o);
  245. switch (o->gch.tt) {
  246. case LUA_TTABLE: {
  247. Table *h = gco2h(o);
  248. g->gray = h->gclist;
  249. if (traversetable(g, h)) /* table is weak? */
  250. black2gray(o); /* keep it gray */
  251. return sizeof(Table) + sizeof(TValue) * h->sizearray +
  252. sizeof(Node) * sizenode(h);
  253. }
  254. case LUA_TFUNCTION: {
  255. Closure *cl = gco2cl(o);
  256. g->gray = cl->c.gclist;
  257. traverseclosure(g, cl);
  258. return (cl->c.isC) ? sizeCclosure(cl->c.nupvalues) :
  259. sizeLclosure(cl->l.nupvalues);
  260. }
  261. case LUA_TTHREAD: {
  262. lua_State *th = gco2th(o);
  263. g->gray = th->gclist;
  264. th->gclist = g->grayagain;
  265. g->grayagain = o;
  266. black2gray(o);
  267. traversestack(g, th);
  268. return sizeof(lua_State) + sizeof(TValue) * th->stacksize +
  269. sizeof(CallInfo) * th->size_ci;
  270. }
  271. case LUA_TPROTO: {
  272. Proto *p = gco2p(o);
  273. g->gray = p->gclist;
  274. traverseproto(g, p);
  275. return sizeof(Proto) + sizeof(Proto *) * p->sizep +
  276. sizeof(TValue) * p->sizek +
  277. sizeof(LocVar) * p->sizelocvars +
  278. sizeof(TString *) * p->sizeupvalues +
  279. (proto_is_readonly(p) ? 0 : sizeof(Instruction) * p->sizecode +
  280. #ifdef LUA_OPTIMIZE_DEBUG
  281. (p->packedlineinfo ?
  282. c_strlen(cast(char *, p->packedlineinfo))+1 :
  283. 0));
  284. #else
  285. sizeof(int) * p->sizelineinfo);
  286. #endif
  287. }
  288. default: lua_assert(0); return 0;
  289. }
  290. }
  291. static size_t propagateall (global_State *g) {
  292. size_t m = 0;
  293. while (g->gray) m += propagatemark(g);
  294. return m;
  295. }
  296. /*
  297. ** The next function tells whether a key or value can be cleared from
  298. ** a weak table. Non-collectable objects are never removed from weak
  299. ** tables. Strings behave as `values', so are never removed too. for
  300. ** other objects: if really collected, cannot keep them; for userdata
  301. ** being finalized, keep them in keys, but not in values
  302. */
  303. static int iscleared (const TValue *o, int iskey) {
  304. if (!iscollectable(o)) return 0;
  305. if (ttisstring(o)) {
  306. stringmark(rawtsvalue(o)); /* strings are `values', so are never weak */
  307. return 0;
  308. }
  309. return iswhite(gcvalue(o)) ||
  310. (ttisuserdata(o) && (!iskey && isfinalized(uvalue(o))));
  311. }
  312. /*
  313. ** clear collected entries from weaktables
  314. */
  315. static void cleartable (GCObject *l) {
  316. while (l) {
  317. Table *h = gco2h(l);
  318. int i = h->sizearray;
  319. lua_assert(testbit(h->marked, VALUEWEAKBIT) ||
  320. testbit(h->marked, KEYWEAKBIT));
  321. if (testbit(h->marked, VALUEWEAKBIT)) {
  322. while (i--) {
  323. TValue *o = &h->array[i];
  324. if (iscleared(o, 0)) /* value was collected? */
  325. setnilvalue(o); /* remove value */
  326. }
  327. }
  328. i = sizenode(h);
  329. while (i--) {
  330. Node *n = gnode(h, i);
  331. if (!ttisnil(gval(n)) && /* non-empty entry? */
  332. (iscleared(key2tval(n), 1) || iscleared(gval(n), 0))) {
  333. setnilvalue(gval(n)); /* remove value ... */
  334. removeentry(n); /* remove entry from table */
  335. }
  336. }
  337. l = h->gclist;
  338. }
  339. }
  340. static void freeobj (lua_State *L, GCObject *o) {
  341. switch (o->gch.tt) {
  342. case LUA_TPROTO: luaF_freeproto(L, gco2p(o)); break;
  343. case LUA_TFUNCTION: luaF_freeclosure(L, gco2cl(o)); break;
  344. case LUA_TUPVAL: luaF_freeupval(L, gco2uv(o)); break;
  345. case LUA_TTABLE: luaH_free(L, gco2h(o)); break;
  346. case LUA_TTHREAD: {
  347. lua_assert(gco2th(o) != L && gco2th(o) != G(L)->mainthread);
  348. luaE_freethread(L, gco2th(o));
  349. break;
  350. }
  351. case LUA_TSTRING: {
  352. G(L)->strt.nuse--;
  353. luaM_freemem(L, o, sizestring(gco2ts(o)));
  354. break;
  355. }
  356. case LUA_TUSERDATA: {
  357. luaM_freemem(L, o, sizeudata(gco2u(o)));
  358. break;
  359. }
  360. default: lua_assert(0);
  361. }
  362. }
  363. #define sweepwholelist(L,p) sweeplist(L,p,MAX_LUMEM)
  364. static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
  365. GCObject *curr;
  366. global_State *g = G(L);
  367. int deadmask = otherwhite(g);
  368. while ((curr = *p) != NULL && count-- > 0) {
  369. if (curr->gch.tt == LUA_TTHREAD) /* sweep open upvalues of each thread */
  370. sweepwholelist(L, &gco2th(curr)->openupval);
  371. if ((curr->gch.marked ^ WHITEBITS) & deadmask) { /* not dead? */
  372. lua_assert(!isdead(g, curr) || testbit(curr->gch.marked, FIXEDBIT));
  373. makewhite(g, curr); /* make it white (for next cycle) */
  374. p = &curr->gch.next;
  375. }
  376. else { /* must erase `curr' */
  377. lua_assert(isdead(g, curr) || deadmask == bitmask(SFIXEDBIT));
  378. *p = curr->gch.next;
  379. freeobj(L, curr);
  380. }
  381. }
  382. return p;
  383. }
  384. static void checkSizes (lua_State *L) {
  385. global_State *g = G(L);
  386. /* check size of string hash */
  387. if (g->strt.nuse < cast(lu_int32, g->strt.size/4) &&
  388. g->strt.size > MINSTRTABSIZE*2)
  389. luaS_resize(L, g->strt.size/2); /* table is too big */
  390. /* it is not safe to re-size the buffer if it is in use. */
  391. if (luaZ_bufflen(&g->buff) > 0) return;
  392. /* check size of buffer */
  393. if (luaZ_sizebuffer(&g->buff) > LUA_MINBUFFER*2) { /* buffer too big? */
  394. size_t newsize = luaZ_sizebuffer(&g->buff) / 2;
  395. luaZ_resizebuffer(L, &g->buff, newsize);
  396. }
  397. }
  398. static void GCTM (lua_State *L) {
  399. global_State *g = G(L);
  400. GCObject *o = g->tmudata->gch.next; /* get first element */
  401. Udata *udata = rawgco2u(o);
  402. const TValue *tm;
  403. /* remove udata from `tmudata' */
  404. if (o == g->tmudata) /* last element? */
  405. g->tmudata = NULL;
  406. else
  407. g->tmudata->gch.next = udata->uv.next;
  408. udata->uv.next = g->mainthread->next; /* return it to `root' list */
  409. g->mainthread->next = o;
  410. makewhite(g, o);
  411. tm = fasttm(L, udata->uv.metatable, TM_GC);
  412. if (tm != NULL) {
  413. lu_byte oldah = L->allowhook;
  414. lu_mem oldt = g->GCthreshold;
  415. L->allowhook = 0; /* stop debug hooks during GC tag method */
  416. g->GCthreshold = 2*g->totalbytes; /* avoid GC steps */
  417. setobj2s(L, L->top, tm);
  418. setuvalue(L, L->top+1, udata);
  419. L->top += 2;
  420. luaD_call(L, L->top - 2, 0);
  421. L->allowhook = oldah; /* restore hooks */
  422. g->GCthreshold = oldt; /* restore threshold */
  423. }
  424. }
  425. /*
  426. ** Call all GC tag methods
  427. */
  428. void luaC_callGCTM (lua_State *L) {
  429. while (G(L)->tmudata)
  430. GCTM(L);
  431. }
  432. void luaC_freeall (lua_State *L) {
  433. global_State *g = G(L);
  434. int i;
  435. g->currentwhite = WHITEBITS | bitmask(SFIXEDBIT); /* mask to collect all elements */
  436. sweepwholelist(L, &g->rootgc);
  437. for (i = 0; i < g->strt.size; i++) /* free all string lists */
  438. sweepwholelist(L, &g->strt.hash[i]);
  439. }
  440. static void markmt (global_State *g) {
  441. int i;
  442. for (i=0; i<NUM_TAGS; i++)
  443. if (g->mt[i] && !luaR_isrotable(g->mt[i])) markobject(g, g->mt[i]);
  444. }
  445. /* mark root set */
  446. static void markroot (lua_State *L) {
  447. global_State *g = G(L);
  448. g->gray = NULL;
  449. g->grayagain = NULL;
  450. g->weak = NULL;
  451. markobject(g, g->mainthread);
  452. /* make global table be traversed before main stack */
  453. markvalue(g, gt(g->mainthread));
  454. markvalue(g, registry(L));
  455. markmt(g);
  456. g->gcstate = GCSpropagate;
  457. }
  458. static void remarkupvals (global_State *g) {
  459. UpVal *uv;
  460. for (uv = g->uvhead.u.l.next; uv != &g->uvhead; uv = uv->u.l.next) {
  461. lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
  462. if (isgray(obj2gco(uv)))
  463. markvalue(g, uv->v);
  464. }
  465. }
  466. static void atomic (lua_State *L) {
  467. global_State *g = G(L);
  468. size_t udsize; /* total size of userdata to be finalized */
  469. /* remark occasional upvalues of (maybe) dead threads */
  470. remarkupvals(g);
  471. /* traverse objects cautch by write barrier and by 'remarkupvals' */
  472. propagateall(g);
  473. /* remark weak tables */
  474. g->gray = g->weak;
  475. g->weak = NULL;
  476. lua_assert(!iswhite(obj2gco(g->mainthread)));
  477. markobject(g, L); /* mark running thread */
  478. markmt(g); /* mark basic metatables (again) */
  479. propagateall(g);
  480. /* remark gray again */
  481. g->gray = g->grayagain;
  482. g->grayagain = NULL;
  483. propagateall(g);
  484. udsize = luaC_separateudata(L, 0); /* separate userdata to be finalized */
  485. marktmu(g); /* mark `preserved' userdata */
  486. udsize += propagateall(g); /* remark, to propagate `preserveness' */
  487. cleartable(g->weak); /* remove collected objects from weak tables */
  488. /* flip current white */
  489. g->currentwhite = cast_byte(otherwhite(g));
  490. g->sweepstrgc = 0;
  491. g->sweepgc = &g->rootgc;
  492. g->gcstate = GCSsweepstring;
  493. g->estimate = g->totalbytes - udsize; /* first estimate */
  494. }
  495. static void sweepstrstep (global_State *g, lua_State *L) {
  496. lu_mem old = g->totalbytes;
  497. sweepwholelist(L, &g->strt.hash[g->sweepstrgc++]);
  498. if (g->sweepstrgc >= g->strt.size) /* nothing more to sweep? */
  499. g->gcstate = GCSsweep; /* end sweep-string phase */
  500. lua_assert(old >= g->totalbytes);
  501. g->estimate -= old - g->totalbytes;
  502. }
  503. static l_mem singlestep (lua_State *L) {
  504. global_State *g = G(L);
  505. /*lua_checkmemory(L);*/
  506. switch (g->gcstate) {
  507. case GCSpause: {
  508. markroot(L); /* start a new collection */
  509. return 0;
  510. }
  511. case GCSpropagate: {
  512. if (g->gray)
  513. return propagatemark(g);
  514. else { /* no more `gray' objects */
  515. atomic(L); /* finish mark phase */
  516. return 0;
  517. }
  518. }
  519. case GCSsweepstring: {
  520. sweepstrstep(g, L);
  521. return GCSWEEPCOST;
  522. }
  523. case GCSsweep: {
  524. lu_mem old = g->totalbytes;
  525. g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
  526. if (*g->sweepgc == NULL) { /* nothing more to sweep? */
  527. checkSizes(L);
  528. g->gcstate = GCSfinalize; /* end sweep phase */
  529. }
  530. lua_assert(old >= g->totalbytes);
  531. g->estimate -= old - g->totalbytes;
  532. return GCSWEEPMAX*GCSWEEPCOST;
  533. }
  534. case GCSfinalize: {
  535. if (g->tmudata) {
  536. GCTM(L);
  537. if (g->estimate > GCFINALIZECOST)
  538. g->estimate -= GCFINALIZECOST;
  539. return GCFINALIZECOST;
  540. }
  541. else {
  542. g->gcstate = GCSpause; /* end collection */
  543. g->gcdept = 0;
  544. return 0;
  545. }
  546. }
  547. default: lua_assert(0); return 0;
  548. }
  549. }
  550. void luaC_step (lua_State *L) {
  551. global_State *g = G(L);
  552. if(is_block_gc(L)) return;
  553. set_block_gc(L);
  554. l_mem lim = (GCSTEPSIZE/100) * g->gcstepmul;
  555. if (lim == 0)
  556. lim = (MAX_LUMEM-1)/2; /* no limit */
  557. g->gcdept += g->totalbytes - g->GCthreshold;
  558. if (g->estimate > g->totalbytes)
  559. g->estimate = g->totalbytes;
  560. do {
  561. lim -= singlestep(L);
  562. if (g->gcstate == GCSpause)
  563. break;
  564. } while (lim > 0);
  565. if (g->gcstate != GCSpause) {
  566. if (g->gcdept < GCSTEPSIZE)
  567. g->GCthreshold = g->totalbytes + GCSTEPSIZE; /* - lim/g->gcstepmul;*/
  568. else {
  569. g->gcdept -= GCSTEPSIZE;
  570. g->GCthreshold = g->totalbytes;
  571. }
  572. }
  573. else {
  574. lua_assert(g->totalbytes >= g->estimate);
  575. setthreshold(g);
  576. }
  577. unset_block_gc(L);
  578. }
  579. int luaC_sweepstrgc (lua_State *L) {
  580. global_State *g = G(L);
  581. if (g->gcstate == GCSsweepstring) {
  582. sweepstrstep(g, L);
  583. return (g->gcstate == GCSsweepstring) ? 1 : 0;
  584. }
  585. return 0;
  586. }
  587. void luaC_fullgc (lua_State *L) {
  588. global_State *g = G(L);
  589. if(is_block_gc(L)) return;
  590. set_block_gc(L);
  591. if (g->gcstate <= GCSpropagate) {
  592. /* reset sweep marks to sweep all elements (returning them to white) */
  593. g->sweepstrgc = 0;
  594. g->sweepgc = &g->rootgc;
  595. /* reset other collector lists */
  596. g->gray = NULL;
  597. g->grayagain = NULL;
  598. g->weak = NULL;
  599. g->gcstate = GCSsweepstring;
  600. }
  601. lua_assert(g->gcstate != GCSpause && g->gcstate != GCSpropagate);
  602. /* finish any pending sweep phase */
  603. while (g->gcstate != GCSfinalize) {
  604. lua_assert(g->gcstate == GCSsweepstring || g->gcstate == GCSsweep);
  605. singlestep(L);
  606. }
  607. markroot(L);
  608. while (g->gcstate != GCSpause) {
  609. singlestep(L);
  610. }
  611. setthreshold(g);
  612. unset_block_gc(L);
  613. }
  614. void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v) {
  615. global_State *g = G(L);
  616. lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o));
  617. lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
  618. lua_assert(ttype(&o->gch) != LUA_TTABLE);
  619. /* must keep invariant? */
  620. if (g->gcstate == GCSpropagate)
  621. reallymarkobject(g, v); /* restore invariant */
  622. else /* don't mind */
  623. makewhite(g, o); /* mark as white just to avoid other barriers */
  624. }
  625. void luaC_barrierback (lua_State *L, Table *t) {
  626. global_State *g = G(L);
  627. GCObject *o = obj2gco(t);
  628. lua_assert(isblack(o) && !isdead(g, o));
  629. lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
  630. black2gray(o); /* make table gray (again) */
  631. t->gclist = g->grayagain;
  632. g->grayagain = o;
  633. }
  634. void luaC_marknew (lua_State *L, GCObject *o) {
  635. global_State *g = G(L);
  636. o->gch.marked = luaC_white(g);
  637. if (g->gcstate == GCSpropagate)
  638. reallymarkobject(g, o); /* mark new objects as gray during propagate state. */
  639. }
  640. void luaC_link (lua_State *L, GCObject *o, lu_byte tt) {
  641. global_State *g = G(L);
  642. o->gch.next = g->rootgc;
  643. g->rootgc = o;
  644. o->gch.marked = luaC_white(g);
  645. o->gch.tt = tt;
  646. }
  647. void luaC_linkupval (lua_State *L, UpVal *uv) {
  648. global_State *g = G(L);
  649. GCObject *o = obj2gco(uv);
  650. o->gch.next = g->rootgc; /* link upvalue into `rootgc' list */
  651. g->rootgc = o;
  652. if (isgray(o)) {
  653. if (g->gcstate == GCSpropagate) {
  654. gray2black(o); /* closed upvalues need barrier */
  655. luaC_barrier(L, uv, uv->v);
  656. }
  657. else { /* sweep phase: sweep it (turning it into white) */
  658. makewhite(g, o);
  659. lua_assert(g->gcstate != GCSfinalize && g->gcstate != GCSpause);
  660. }
  661. }
  662. }