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