diff options
Diffstat (limited to 'plugins/MirLua/src/lua/lgc.c')
| -rw-r--r-- | plugins/MirLua/src/lua/lgc.c | 1183 |
1 files changed, 0 insertions, 1183 deletions
diff --git a/plugins/MirLua/src/lua/lgc.c b/plugins/MirLua/src/lua/lgc.c deleted file mode 100644 index 49d8ecb7c3..0000000000 --- a/plugins/MirLua/src/lua/lgc.c +++ /dev/null @@ -1,1183 +0,0 @@ -/* -** $Id: lgc.c,v 2.210 2015/11/03 18:10:44 roberto Exp $ -** Garbage Collector -** See Copyright Notice in lua.h -*/ - -#define lgc_c -#define LUA_CORE - -#include "lprefix.h" - - -#include <string.h> - -#include "lua.h" - -#include "ldebug.h" -#include "ldo.h" -#include "lfunc.h" -#include "lgc.h" -#include "lmem.h" -#include "lobject.h" -#include "lstate.h" -#include "lstring.h" -#include "ltable.h" -#include "ltm.h" - - -/* -** internal state for collector while inside the atomic phase. The -** collector should never be in this state while running regular code. -*/ -#define GCSinsideatomic (GCSpause + 1) - -/* -** cost of sweeping one element (the size of a small object divided -** by some adjust for the sweep speed) -*/ -#define GCSWEEPCOST ((sizeof(TString) + 4) / 4) - -/* maximum number of elements to sweep in each single step */ -#define GCSWEEPMAX (cast_int((GCSTEPSIZE / GCSWEEPCOST) / 4)) - -/* cost of calling one finalizer */ -#define GCFINALIZECOST GCSWEEPCOST - - -/* -** macro to adjust 'stepmul': 'stepmul' is actually used like -** 'stepmul / STEPMULADJ' (value chosen by tests) -*/ -#define STEPMULADJ 200 - - -/* -** macro to adjust 'pause': 'pause' is actually used like -** 'pause / PAUSEADJ' (value chosen by tests) -*/ -#define PAUSEADJ 100 - - -/* -** 'makewhite' erases all color bits then sets only the current white -** bit -*/ -#define maskcolors (~(bitmask(BLACKBIT) | WHITEBITS)) -#define makewhite(g,x) \ - (x->marked = cast_byte((x->marked & maskcolors) | luaC_white(g))) - -#define white2gray(x) resetbits(x->marked, WHITEBITS) -#define black2gray(x) resetbit(x->marked, BLACKBIT) - - -#define valiswhite(x) (iscollectable(x) && iswhite(gcvalue(x))) - -#define checkdeadkey(n) lua_assert(!ttisdeadkey(gkey(n)) || ttisnil(gval(n))) - - -#define checkconsistency(obj) \ - lua_longassert(!iscollectable(obj) || righttt(obj)) - - -#define markvalue(g,o) { checkconsistency(o); \ - if (valiswhite(o)) reallymarkobject(g,gcvalue(o)); } - -#define markobject(g,t) { if (iswhite(t)) reallymarkobject(g, obj2gco(t)); } - -/* -** mark an object that can be NULL (either because it is really optional, -** or it was stripped as debug info, or inside an uncompleted structure) -*/ -#define markobjectN(g,t) { if (t) markobject(g,t); } - -static void reallymarkobject (global_State *g, GCObject *o); - - -/* -** {====================================================== -** Generic functions -** ======================================================= -*/ - - -/* -** one after last element in a hash array -*/ -#define gnodelast(h) gnode(h, cast(size_t, sizenode(h))) - - -/* -** link collectable object 'o' into list pointed by 'p' -*/ -#define linkgclist(o,p) ((o)->gclist = (p), (p) = obj2gco(o)) - - -/* -** If key is not marked, mark its entry as dead. This allows key to be -** collected, but keeps its entry in the table. A dead node is needed -** when Lua looks up for a key (it may be part of a chain) and when -** traversing a weak table (key might be removed from the table during -** traversal). Other places never manipulate dead keys, because its -** associated nil value is enough to signal that the entry is logically -** empty. -*/ -static void removeentry (Node *n) { - lua_assert(ttisnil(gval(n))); - if (valiswhite(gkey(n))) - setdeadvalue(wgkey(n)); /* unused and unmarked key; remove it */ -} - - -/* -** tells whether a key or value can be cleared from a weak -** table. Non-collectable objects are never removed from weak -** tables. Strings behave as 'values', so are never removed too. for -** other objects: if really collected, cannot keep them; for objects -** being finalized, keep them in keys, but not in values -*/ -static int iscleared (global_State *g, const TValue *o) { - if (!iscollectable(o)) return 0; - else if (ttisstring(o)) { - markobject(g, tsvalue(o)); /* strings are 'values', so are never weak */ - return 0; - } - else return iswhite(gcvalue(o)); -} - - -/* -** barrier that moves collector forward, that is, mark the white object -** being pointed by a black object. (If in sweep phase, clear the black -** object to white [sweep it] to avoid other barrier calls for this -** same object.) -*/ -void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v) { - global_State *g = G(L); - lua_assert(isblack(o) && iswhite(v) && !isdead(g, v) && !isdead(g, o)); - if (keepinvariant(g)) /* must keep invariant? */ - reallymarkobject(g, v); /* restore invariant */ - else { /* sweep phase */ - lua_assert(issweepphase(g)); - makewhite(g, o); /* mark main obj. as white to avoid other barriers */ - } -} - - -/* -** barrier that moves collector backward, that is, mark the black object -** pointing to a white object as gray again. -*/ -void luaC_barrierback_ (lua_State *L, Table *t) { - global_State *g = G(L); - lua_assert(isblack(t) && !isdead(g, t)); - black2gray(t); /* make table gray (again) */ - linkgclist(t, g->grayagain); -} - - -/* -** barrier for assignments to closed upvalues. Because upvalues are -** shared among closures, it is impossible to know the color of all -** closures pointing to it. So, we assume that the object being assigned -** must be marked. -*/ -void luaC_upvalbarrier_ (lua_State *L, UpVal *uv) { - global_State *g = G(L); - GCObject *o = gcvalue(uv->v); - lua_assert(!upisopen(uv)); /* ensured by macro luaC_upvalbarrier */ - if (keepinvariant(g)) - markobject(g, o); -} - - -void luaC_fix (lua_State *L, GCObject *o) { - global_State *g = G(L); - lua_assert(g->allgc == o); /* object must be 1st in 'allgc' list! */ - white2gray(o); /* they will be gray forever */ - g->allgc = o->next; /* remove object from 'allgc' list */ - o->next = g->fixedgc; /* link it to 'fixedgc' list */ - g->fixedgc = o; -} - - -/* -** create a new collectable object (with given type and size) and link -** it to 'allgc' list. -*/ -GCObject *luaC_newobj (lua_State *L, int tt, size_t sz) { - global_State *g = G(L); - GCObject *o = cast(GCObject *, luaM_newobject(L, novariant(tt), sz)); - o->marked = luaC_white(g); - o->tt = tt; - o->next = g->allgc; - g->allgc = o; - return o; -} - -/* }====================================================== */ - - - -/* -** {====================================================== -** Mark functions -** ======================================================= -*/ - - -/* -** mark an object. Userdata, strings, and closed upvalues are visited -** and turned black here. Other objects are marked gray and added -** to appropriate list to be visited (and turned black) later. (Open -** upvalues are already linked in 'headuv' list.) -*/ -static void reallymarkobject (global_State *g, GCObject *o) { - reentry: - white2gray(o); - switch (o->tt) { - case LUA_TSHRSTR: { - gray2black(o); - g->GCmemtrav += sizelstring(gco2ts(o)->shrlen); - break; - } - case LUA_TLNGSTR: { - gray2black(o); - g->GCmemtrav += sizelstring(gco2ts(o)->u.lnglen); - break; - } - case LUA_TUSERDATA: { - TValue uvalue; - markobjectN(g, gco2u(o)->metatable); /* mark its metatable */ - gray2black(o); - g->GCmemtrav += sizeudata(gco2u(o)); - getuservalue(g->mainthread, gco2u(o), &uvalue); - if (valiswhite(&uvalue)) { /* markvalue(g, &uvalue); */ - o = gcvalue(&uvalue); - goto reentry; - } - break; - } - case LUA_TLCL: { - linkgclist(gco2lcl(o), g->gray); - break; - } - case LUA_TCCL: { - linkgclist(gco2ccl(o), g->gray); - break; - } - case LUA_TTABLE: { - linkgclist(gco2t(o), g->gray); - break; - } - case LUA_TTHREAD: { - linkgclist(gco2th(o), g->gray); - break; - } - case LUA_TPROTO: { - linkgclist(gco2p(o), g->gray); - break; - } - default: lua_assert(0); break; - } -} - - -/* -** mark metamethods for basic types -*/ -static void markmt (global_State *g) { - int i; - for (i=0; i < LUA_NUMTAGS; i++) - markobjectN(g, g->mt[i]); -} - - -/* -** mark all objects in list of being-finalized -*/ -static void markbeingfnz (global_State *g) { - GCObject *o; - for (o = g->tobefnz; o != NULL; o = o->next) - markobject(g, o); -} - - -/* -** Mark all values stored in marked open upvalues from non-marked threads. -** (Values from marked threads were already marked when traversing the -** thread.) Remove from the list threads that no longer have upvalues and -** not-marked threads. -*/ -static void remarkupvals (global_State *g) { - lua_State *thread; - lua_State **p = &g->twups; - while ((thread = *p) != NULL) { - lua_assert(!isblack(thread)); /* threads are never black */ - if (isgray(thread) && thread->openupval != NULL) - p = &thread->twups; /* keep marked thread with upvalues in the list */ - else { /* thread is not marked or without upvalues */ - UpVal *uv; - *p = thread->twups; /* remove thread from the list */ - thread->twups = thread; /* mark that it is out of list */ - for (uv = thread->openupval; uv != NULL; uv = uv->u.open.next) { - if (uv->u.open.touched) { - markvalue(g, uv->v); /* remark upvalue's value */ - uv->u.open.touched = 0; - } - } - } - } -} - - -/* -** mark root set and reset all gray lists, to start a new collection -*/ -static void restartcollection (global_State *g) { - g->gray = g->grayagain = NULL; - g->weak = g->allweak = g->ephemeron = NULL; - markobject(g, g->mainthread); - markvalue(g, &g->l_registry); - markmt(g); - markbeingfnz(g); /* mark any finalizing object left from previous cycle */ -} - -/* }====================================================== */ - - -/* -** {====================================================== -** Traverse functions -** ======================================================= -*/ - -/* -** Traverse a table with weak values and link it to proper list. During -** propagate phase, keep it in 'grayagain' list, to be revisited in the -** atomic phase. In the atomic phase, if table has any white value, -** put it in 'weak' list, to be cleared. -*/ -static void traverseweakvalue (global_State *g, Table *h) { - Node *n, *limit = gnodelast(h); - /* if there is array part, assume it may have white values (it is not - worth traversing it now just to check) */ - int hasclears = (h->sizearray > 0); - for (n = gnode(h, 0); n < limit; n++) { /* traverse hash part */ - checkdeadkey(n); - if (ttisnil(gval(n))) /* entry is empty? */ - removeentry(n); /* remove it */ - else { - lua_assert(!ttisnil(gkey(n))); - markvalue(g, gkey(n)); /* mark key */ - if (!hasclears && iscleared(g, gval(n))) /* is there a white value? */ - hasclears = 1; /* table will have to be cleared */ - } - } - if (g->gcstate == GCSpropagate) - linkgclist(h, g->grayagain); /* must retraverse it in atomic phase */ - else if (hasclears) - linkgclist(h, g->weak); /* has to be cleared later */ -} - - -/* -** Traverse an ephemeron table and link it to proper list. Returns true -** iff any object was marked during this traversal (which implies that -** convergence has to continue). During propagation phase, keep table -** in 'grayagain' list, to be visited again in the atomic phase. In -** the atomic phase, if table has any white->white entry, it has to -** be revisited during ephemeron convergence (as that key may turn -** black). Otherwise, if it has any white key, table has to be cleared -** (in the atomic phase). -*/ -static int traverseephemeron (global_State *g, Table *h) { - int marked = 0; /* true if an object is marked in this traversal */ - int hasclears = 0; /* true if table has white keys */ - int hasww = 0; /* true if table has entry "white-key -> white-value" */ - Node *n, *limit = gnodelast(h); - unsigned int i; - /* traverse array part */ - for (i = 0; i < h->sizearray; i++) { - if (valiswhite(&h->array[i])) { - marked = 1; - reallymarkobject(g, gcvalue(&h->array[i])); - } - } - /* traverse hash part */ - for (n = gnode(h, 0); n < limit; n++) { - checkdeadkey(n); - if (ttisnil(gval(n))) /* entry is empty? */ - removeentry(n); /* remove it */ - else if (iscleared(g, gkey(n))) { /* key is not marked (yet)? */ - hasclears = 1; /* table must be cleared */ - if (valiswhite(gval(n))) /* value not marked yet? */ - hasww = 1; /* white-white entry */ - } - else if (valiswhite(gval(n))) { /* value not marked yet? */ - marked = 1; - reallymarkobject(g, gcvalue(gval(n))); /* mark it now */ - } - } - /* link table into proper list */ - if (g->gcstate == GCSpropagate) - linkgclist(h, g->grayagain); /* must retraverse it in atomic phase */ - else if (hasww) /* table has white->white entries? */ - linkgclist(h, g->ephemeron); /* have to propagate again */ - else if (hasclears) /* table has white keys? */ - linkgclist(h, g->allweak); /* may have to clean white keys */ - return marked; -} - - -static void traversestrongtable (global_State *g, Table *h) { - Node *n, *limit = gnodelast(h); - unsigned int i; - for (i = 0; i < h->sizearray; i++) /* traverse array part */ - markvalue(g, &h->array[i]); - for (n = gnode(h, 0); n < limit; n++) { /* traverse hash part */ - checkdeadkey(n); - if (ttisnil(gval(n))) /* entry is empty? */ - removeentry(n); /* remove it */ - else { - lua_assert(!ttisnil(gkey(n))); - markvalue(g, gkey(n)); /* mark key */ - markvalue(g, gval(n)); /* mark value */ - } - } -} - - -static lu_mem traversetable (global_State *g, Table *h) { - const char *weakkey, *weakvalue; - const TValue *mode = gfasttm(g, h->metatable, TM_MODE); - markobjectN(g, h->metatable); - if (mode && ttisstring(mode) && /* is there a weak mode? */ - ((weakkey = strchr(svalue(mode), 'k')), - (weakvalue = strchr(svalue(mode), 'v')), - (weakkey || weakvalue))) { /* is really weak? */ - black2gray(h); /* keep table gray */ - if (!weakkey) /* strong keys? */ - traverseweakvalue(g, h); - else if (!weakvalue) /* strong values? */ - traverseephemeron(g, h); - else /* all weak */ - linkgclist(h, g->allweak); /* nothing to traverse now */ - } - else /* not weak */ - traversestrongtable(g, h); - return sizeof(Table) + sizeof(TValue) * h->sizearray + - sizeof(Node) * cast(size_t, sizenode(h)); -} - - -/* -** Traverse a prototype. (While a prototype is being build, its -** arrays can be larger than needed; the extra slots are filled with -** NULL, so the use of 'markobjectN') -*/ -static int traverseproto (global_State *g, Proto *f) { - int i; - if (f->cache && iswhite(f->cache)) - f->cache = NULL; /* allow cache to be collected */ - markobjectN(g, f->source); - for (i = 0; i < f->sizek; i++) /* mark literals */ - markvalue(g, &f->k[i]); - for (i = 0; i < f->sizeupvalues; i++) /* mark upvalue names */ - markobjectN(g, f->upvalues[i].name); - for (i = 0; i < f->sizep; i++) /* mark nested protos */ - markobjectN(g, f->p[i]); - for (i = 0; i < f->sizelocvars; i++) /* mark local-variable names */ - markobjectN(g, f->locvars[i].varname); - return sizeof(Proto) + sizeof(Instruction) * f->sizecode + - sizeof(Proto *) * f->sizep + - sizeof(TValue) * f->sizek + - sizeof(int) * f->sizelineinfo + - sizeof(LocVar) * f->sizelocvars + - sizeof(Upvaldesc) * f->sizeupvalues; -} - - -static lu_mem traverseCclosure (global_State *g, CClosure *cl) { - int i; - for (i = 0; i < cl->nupvalues; i++) /* mark its upvalues */ - markvalue(g, &cl->upvalue[i]); - return sizeCclosure(cl->nupvalues); -} - -/* -** open upvalues point to values in a thread, so those values should -** be marked when the thread is traversed except in the atomic phase -** (because then the value cannot be changed by the thread and the -** thread may not be traversed again) -*/ -static lu_mem traverseLclosure (global_State *g, LClosure *cl) { - int i; - markobjectN(g, cl->p); /* mark its prototype */ - for (i = 0; i < cl->nupvalues; i++) { /* mark its upvalues */ - UpVal *uv = cl->upvals[i]; - if (uv != NULL) { - if (upisopen(uv) && g->gcstate != GCSinsideatomic) - uv->u.open.touched = 1; /* can be marked in 'remarkupvals' */ - else - markvalue(g, uv->v); - } - } - return sizeLclosure(cl->nupvalues); -} - - -static lu_mem traversethread (global_State *g, lua_State *th) { - StkId o = th->stack; - if (o == NULL) - return 1; /* stack not completely built yet */ - lua_assert(g->gcstate == GCSinsideatomic || - th->openupval == NULL || isintwups(th)); - for (; o < th->top; o++) /* mark live elements in the stack */ - markvalue(g, o); - if (g->gcstate == GCSinsideatomic) { /* final traversal? */ - StkId lim = th->stack + th->stacksize; /* real end of stack */ - for (; o < lim; o++) /* clear not-marked stack slice */ - setnilvalue(o); - /* 'remarkupvals' may have removed thread from 'twups' list */ - if (!isintwups(th) && th->openupval != NULL) { - th->twups = g->twups; /* link it back to the list */ - g->twups = th; - } - } - else if (g->gckind != KGC_EMERGENCY) - luaD_shrinkstack(th); /* do not change stack in emergency cycle */ - return (sizeof(lua_State) + sizeof(TValue) * th->stacksize + - sizeof(CallInfo) * th->nci); -} - - -/* -** traverse one gray object, turning it to black (except for threads, -** which are always gray). -*/ -static void propagatemark (global_State *g) { - lu_mem size; - GCObject *o = g->gray; - lua_assert(isgray(o)); - gray2black(o); - switch (o->tt) { - case LUA_TTABLE: { - Table *h = gco2t(o); - g->gray = h->gclist; /* remove from 'gray' list */ - size = traversetable(g, h); - break; - } - case LUA_TLCL: { - LClosure *cl = gco2lcl(o); - g->gray = cl->gclist; /* remove from 'gray' list */ - size = traverseLclosure(g, cl); - break; - } - case LUA_TCCL: { - CClosure *cl = gco2ccl(o); - g->gray = cl->gclist; /* remove from 'gray' list */ - size = traverseCclosure(g, cl); - break; - } - case LUA_TTHREAD: { - lua_State *th = gco2th(o); - g->gray = th->gclist; /* remove from 'gray' list */ - linkgclist(th, g->grayagain); /* insert into 'grayagain' list */ - black2gray(o); - size = traversethread(g, th); - break; - } - case LUA_TPROTO: { - Proto *p = gco2p(o); - g->gray = p->gclist; /* remove from 'gray' list */ - size = traverseproto(g, p); - break; - } - default: lua_assert(0); return; - } - g->GCmemtrav += size; -} - - -static void propagateall (global_State *g) { - while (g->gray) propagatemark(g); -} - - -static void convergeephemerons (global_State *g) { - int changed; - do { - GCObject *w; - GCObject *next = g->ephemeron; /* get ephemeron list */ - g->ephemeron = NULL; /* tables may return to this list when traversed */ - changed = 0; - while ((w = next) != NULL) { - next = gco2t(w)->gclist; - if (traverseephemeron(g, gco2t(w))) { /* traverse marked some value? */ - propagateall(g); /* propagate changes */ - changed = 1; /* will have to revisit all ephemeron tables */ - } - } - } while (changed); -} - -/* }====================================================== */ - - -/* -** {====================================================== -** Sweep Functions -** ======================================================= -*/ - - -/* -** clear entries with unmarked keys from all weaktables in list 'l' up -** to element 'f' -*/ -static void clearkeys (global_State *g, GCObject *l, GCObject *f) { - for (; l != f; l = gco2t(l)->gclist) { - Table *h = gco2t(l); - Node *n, *limit = gnodelast(h); - for (n = gnode(h, 0); n < limit; n++) { - if (!ttisnil(gval(n)) && (iscleared(g, gkey(n)))) { - setnilvalue(gval(n)); /* remove value ... */ - removeentry(n); /* and remove entry from table */ - } - } - } -} - - -/* -** clear entries with unmarked values from all weaktables in list 'l' up -** to element 'f' -*/ -static void clearvalues (global_State *g, GCObject *l, GCObject *f) { - for (; l != f; l = gco2t(l)->gclist) { - Table *h = gco2t(l); - Node *n, *limit = gnodelast(h); - unsigned int i; - for (i = 0; i < h->sizearray; i++) { - TValue *o = &h->array[i]; - if (iscleared(g, o)) /* value was collected? */ - setnilvalue(o); /* remove value */ - } - for (n = gnode(h, 0); n < limit; n++) { - if (!ttisnil(gval(n)) && iscleared(g, gval(n))) { - setnilvalue(gval(n)); /* remove value ... */ - removeentry(n); /* and remove entry from table */ - } - } - } -} - - -void luaC_upvdeccount (lua_State *L, UpVal *uv) { - lua_assert(uv->refcount > 0); - uv->refcount--; - if (uv->refcount == 0 && !upisopen(uv)) - luaM_free(L, uv); -} - - -static void freeLclosure (lua_State *L, LClosure *cl) { - int i; - for (i = 0; i < cl->nupvalues; i++) { - UpVal *uv = cl->upvals[i]; - if (uv) - luaC_upvdeccount(L, uv); - } - luaM_freemem(L, cl, sizeLclosure(cl->nupvalues)); -} - - -static void freeobj (lua_State *L, GCObject *o) { - switch (o->tt) { - case LUA_TPROTO: luaF_freeproto(L, gco2p(o)); break; - case LUA_TLCL: { - freeLclosure(L, gco2lcl(o)); - break; - } - case LUA_TCCL: { - luaM_freemem(L, o, sizeCclosure(gco2ccl(o)->nupvalues)); - break; - } - case LUA_TTABLE: luaH_free(L, gco2t(o)); break; - case LUA_TTHREAD: luaE_freethread(L, gco2th(o)); break; - case LUA_TUSERDATA: luaM_freemem(L, o, sizeudata(gco2u(o))); break; - case LUA_TSHRSTR: - luaS_remove(L, gco2ts(o)); /* remove it from hash table */ - luaM_freemem(L, o, sizelstring(gco2ts(o)->shrlen)); - break; - case LUA_TLNGSTR: { - luaM_freemem(L, o, sizelstring(gco2ts(o)->u.lnglen)); - break; - } - default: lua_assert(0); - } -} - - -#define sweepwholelist(L,p) sweeplist(L,p,MAX_LUMEM) -static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count); - - -/* -** sweep at most 'count' elements from a list of GCObjects erasing dead -** objects, where a dead object is one marked with the old (non current) -** white; change all non-dead objects back to white, preparing for next -** collection cycle. Return where to continue the traversal or NULL if -** list is finished. -*/ -static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) { - global_State *g = G(L); - int ow = otherwhite(g); - int white = luaC_white(g); /* current white */ - while (*p != NULL && count-- > 0) { - GCObject *curr = *p; - int marked = curr->marked; - if (isdeadm(ow, marked)) { /* is 'curr' dead? */ - *p = curr->next; /* remove 'curr' from list */ - freeobj(L, curr); /* erase 'curr' */ - } - else { /* change mark to 'white' */ - curr->marked = cast_byte((marked & maskcolors) | white); - p = &curr->next; /* go to next element */ - } - } - return (*p == NULL) ? NULL : p; -} - - -/* -** sweep a list until a live object (or end of list) -*/ -static GCObject **sweeptolive (lua_State *L, GCObject **p, int *n) { - GCObject **old = p; - int i = 0; - do { - i++; - p = sweeplist(L, p, 1); - } while (p == old); - if (n) *n += i; - return p; -} - -/* }====================================================== */ - - -/* -** {====================================================== -** Finalization -** ======================================================= -*/ - -/* -** If possible, shrink string table -*/ -static void checkSizes (lua_State *L, global_State *g) { - if (g->gckind != KGC_EMERGENCY) { - l_mem olddebt = g->GCdebt; - if (g->strt.nuse < g->strt.size / 4) /* string table too big? */ - luaS_resize(L, g->strt.size / 2); /* shrink it a little */ - g->GCestimate += g->GCdebt - olddebt; /* update estimate */ - } -} - - -static GCObject *udata2finalize (global_State *g) { - GCObject *o = g->tobefnz; /* get first element */ - lua_assert(tofinalize(o)); - g->tobefnz = o->next; /* remove it from 'tobefnz' list */ - o->next = g->allgc; /* return it to 'allgc' list */ - g->allgc = o; - resetbit(o->marked, FINALIZEDBIT); /* object is "normal" again */ - if (issweepphase(g)) - makewhite(g, o); /* "sweep" object */ - return o; -} - - -static void dothecall (lua_State *L, void *ud) { - UNUSED(ud); - luaD_callnoyield(L, L->top - 2, 0); -} - - -static void GCTM (lua_State *L, int propagateerrors) { - global_State *g = G(L); - const TValue *tm; - TValue v; - setgcovalue(L, &v, udata2finalize(g)); - tm = luaT_gettmbyobj(L, &v, TM_GC); - if (tm != NULL && ttisfunction(tm)) { /* is there a finalizer? */ - int status; - lu_byte oldah = L->allowhook; - int running = g->gcrunning; - L->allowhook = 0; /* stop debug hooks during GC metamethod */ - g->gcrunning = 0; /* avoid GC steps */ - setobj2s(L, L->top, tm); /* push finalizer... */ - setobj2s(L, L->top + 1, &v); /* ... and its argument */ - L->top += 2; /* and (next line) call the finalizer */ - status = luaD_pcall(L, dothecall, NULL, savestack(L, L->top - 2), 0); - L->allowhook = oldah; /* restore hooks */ - g->gcrunning = running; /* restore state */ - if (status != LUA_OK && propagateerrors) { /* error while running __gc? */ - if (status == LUA_ERRRUN) { /* is there an error object? */ - const char *msg = (ttisstring(L->top - 1)) - ? svalue(L->top - 1) - : "no message"; - luaO_pushfstring(L, "error in __gc metamethod (%s)", msg); - status = LUA_ERRGCMM; /* error in __gc metamethod */ - } - luaD_throw(L, status); /* re-throw error */ - } - } -} - - -/* -** call a few (up to 'g->gcfinnum') finalizers -*/ -static int runafewfinalizers (lua_State *L) { - global_State *g = G(L); - unsigned int i; - lua_assert(!g->tobefnz || g->gcfinnum > 0); - for (i = 0; g->tobefnz && i < g->gcfinnum; i++) - GCTM(L, 1); /* call one finalizer */ - g->gcfinnum = (!g->tobefnz) ? 0 /* nothing more to finalize? */ - : g->gcfinnum * 2; /* else call a few more next time */ - return i; -} - - -/* -** call all pending finalizers -*/ -static void callallpendingfinalizers (lua_State *L, int propagateerrors) { - global_State *g = G(L); - while (g->tobefnz) - GCTM(L, propagateerrors); -} - - -/* -** find last 'next' field in list 'p' list (to add elements in its end) -*/ -static GCObject **findlast (GCObject **p) { - while (*p != NULL) - p = &(*p)->next; - return p; -} - - -/* -** move all unreachable objects (or 'all' objects) that need -** finalization from list 'finobj' to list 'tobefnz' (to be finalized) -*/ -static void separatetobefnz (global_State *g, int all) { - GCObject *curr; - GCObject **p = &g->finobj; - GCObject **lastnext = findlast(&g->tobefnz); - while ((curr = *p) != NULL) { /* traverse all finalizable objects */ - lua_assert(tofinalize(curr)); - if (!(iswhite(curr) || all)) /* not being collected? */ - p = &curr->next; /* don't bother with it */ - else { - *p = curr->next; /* remove 'curr' from 'finobj' list */ - curr->next = *lastnext; /* link at the end of 'tobefnz' list */ - *lastnext = curr; - lastnext = &curr->next; - } - } -} - - -/* -** if object 'o' has a finalizer, remove it from 'allgc' list (must -** search the list to find it) and link it in 'finobj' list. -*/ -void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) { - global_State *g = G(L); - if (tofinalize(o) || /* obj. is already marked... */ - gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */ - return; /* nothing to be done */ - else { /* move 'o' to 'finobj' list */ - GCObject **p; - if (issweepphase(g)) { - makewhite(g, o); /* "sweep" object 'o' */ - if (g->sweepgc == &o->next) /* should not remove 'sweepgc' object */ - g->sweepgc = sweeptolive(L, g->sweepgc, NULL); /* change 'sweepgc' */ - } - /* search for pointer pointing to 'o' */ - for (p = &g->allgc; *p != o; p = &(*p)->next) { /* empty */ } - *p = o->next; /* remove 'o' from 'allgc' list */ - o->next = g->finobj; /* link it in 'finobj' list */ - g->finobj = o; - l_setbit(o->marked, FINALIZEDBIT); /* mark it as such */ - } -} - -/* }====================================================== */ - - - -/* -** {====================================================== -** GC control -** ======================================================= -*/ - - -/* -** Set a reasonable "time" to wait before starting a new GC cycle; cycle -** will start when memory use hits threshold. (Division by 'estimate' -** should be OK: it cannot be zero (because Lua cannot even start with -** less than PAUSEADJ bytes). -*/ -static void setpause (global_State *g) { - l_mem threshold, debt; - l_mem estimate = g->GCestimate / PAUSEADJ; /* adjust 'estimate' */ - lua_assert(estimate > 0); - threshold = (g->gcpause < MAX_LMEM / estimate) /* overflow? */ - ? estimate * g->gcpause /* no overflow */ - : MAX_LMEM; /* overflow; truncate to maximum */ - debt = gettotalbytes(g) - threshold; - luaE_setdebt(g, debt); -} - - -/* -** Enter first sweep phase. -** The call to 'sweeptolive' makes pointer point to an object inside -** the list (instead of to the header), so that the real sweep do not -** need to skip objects created between "now" and the start of the real -** sweep. -** Returns how many objects it swept. -*/ -static int entersweep (lua_State *L) { - global_State *g = G(L); - int n = 0; - g->gcstate = GCSswpallgc; - lua_assert(g->sweepgc == NULL); - g->sweepgc = sweeptolive(L, &g->allgc, &n); - return n; -} - - -void luaC_freeallobjects (lua_State *L) { - global_State *g = G(L); - separatetobefnz(g, 1); /* separate all objects with finalizers */ - lua_assert(g->finobj == NULL); - callallpendingfinalizers(L, 0); - lua_assert(g->tobefnz == NULL); - g->currentwhite = WHITEBITS; /* this "white" makes all objects look dead */ - g->gckind = KGC_NORMAL; - sweepwholelist(L, &g->finobj); - sweepwholelist(L, &g->allgc); - sweepwholelist(L, &g->fixedgc); /* collect fixed objects */ - lua_assert(g->strt.nuse == 0); -} - - -static l_mem atomic (lua_State *L) { - global_State *g = G(L); - l_mem work; - GCObject *origweak, *origall; - GCObject *grayagain = g->grayagain; /* save original list */ - lua_assert(g->ephemeron == NULL && g->weak == NULL); - lua_assert(!iswhite(g->mainthread)); - g->gcstate = GCSinsideatomic; - g->GCmemtrav = 0; /* start counting work */ - markobject(g, L); /* mark running thread */ - /* registry and global metatables may be changed by API */ - markvalue(g, &g->l_registry); - markmt(g); /* mark global metatables */ - /* remark occasional upvalues of (maybe) dead threads */ - remarkupvals(g); - propagateall(g); /* propagate changes */ - work = g->GCmemtrav; /* stop counting (do not recount 'grayagain') */ - g->gray = grayagain; - propagateall(g); /* traverse 'grayagain' list */ - g->GCmemtrav = 0; /* restart counting */ - convergeephemerons(g); - /* at this point, all strongly accessible objects are marked. */ - /* Clear values from weak tables, before checking finalizers */ - clearvalues(g, g->weak, NULL); - clearvalues(g, g->allweak, NULL); - origweak = g->weak; origall = g->allweak; - work += g->GCmemtrav; /* stop counting (objects being finalized) */ - separatetobefnz(g, 0); /* separate objects to be finalized */ - g->gcfinnum = 1; /* there may be objects to be finalized */ - markbeingfnz(g); /* mark objects that will be finalized */ - propagateall(g); /* remark, to propagate 'resurrection' */ - g->GCmemtrav = 0; /* restart counting */ - convergeephemerons(g); - /* at this point, all resurrected objects are marked. */ - /* remove dead objects from weak tables */ - clearkeys(g, g->ephemeron, NULL); /* clear keys from all ephemeron tables */ - clearkeys(g, g->allweak, NULL); /* clear keys from all 'allweak' tables */ - /* clear values from resurrected weak tables */ - clearvalues(g, g->weak, origweak); - clearvalues(g, g->allweak, origall); - luaS_clearcache(g); - g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */ - work += g->GCmemtrav; /* complete counting */ - return work; /* estimate of memory marked by 'atomic' */ -} - - -static lu_mem sweepstep (lua_State *L, global_State *g, - int nextstate, GCObject **nextlist) { - if (g->sweepgc) { - l_mem olddebt = g->GCdebt; - g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX); - g->GCestimate += g->GCdebt - olddebt; /* update estimate */ - if (g->sweepgc) /* is there still something to sweep? */ - return (GCSWEEPMAX * GCSWEEPCOST); - } - /* else enter next state */ - g->gcstate = nextstate; - g->sweepgc = nextlist; - return 0; -} - - -static lu_mem singlestep (lua_State *L) { - global_State *g = G(L); - switch (g->gcstate) { - case GCSpause: { - g->GCmemtrav = g->strt.size * sizeof(GCObject*); - restartcollection(g); - g->gcstate = GCSpropagate; - return g->GCmemtrav; - } - case GCSpropagate: { - g->GCmemtrav = 0; - lua_assert(g->gray); - propagatemark(g); - if (g->gray == NULL) /* no more gray objects? */ - g->gcstate = GCSatomic; /* finish propagate phase */ - return g->GCmemtrav; /* memory traversed in this step */ - } - case GCSatomic: { - lu_mem work; - int sw; - propagateall(g); /* make sure gray list is empty */ - work = atomic(L); /* work is what was traversed by 'atomic' */ - sw = entersweep(L); - g->GCestimate = gettotalbytes(g); /* first estimate */; - return work + sw * GCSWEEPCOST; - } - case GCSswpallgc: { /* sweep "regular" objects */ - return sweepstep(L, g, GCSswpfinobj, &g->finobj); - } - case GCSswpfinobj: { /* sweep objects with finalizers */ - return sweepstep(L, g, GCSswptobefnz, &g->tobefnz); - } - case GCSswptobefnz: { /* sweep objects to be finalized */ - return sweepstep(L, g, GCSswpend, NULL); - } - case GCSswpend: { /* finish sweeps */ - makewhite(g, g->mainthread); /* sweep main thread */ - checkSizes(L, g); - g->gcstate = GCScallfin; - return 0; - } - case GCScallfin: { /* call remaining finalizers */ - if (g->tobefnz && g->gckind != KGC_EMERGENCY) { - int n = runafewfinalizers(L); - return (n * GCFINALIZECOST); - } - else { /* emergency mode or no more finalizers */ - g->gcstate = GCSpause; /* finish collection */ - return 0; - } - } - default: lua_assert(0); return 0; - } -} - - -/* -** advances the garbage collector until it reaches a state allowed -** by 'statemask' -*/ -void luaC_runtilstate (lua_State *L, int statesmask) { - global_State *g = G(L); - while (!testbit(statesmask, g->gcstate)) - singlestep(L); -} - - -/* -** get GC debt and convert it from Kb to 'work units' (avoid zero debt -** and overflows) -*/ -static l_mem getdebt (global_State *g) { - l_mem debt = g->GCdebt; - int stepmul = g->gcstepmul; - if (debt <= 0) return 0; /* minimal debt */ - else { - debt = (debt / STEPMULADJ) + 1; - debt = (debt < MAX_LMEM / stepmul) ? debt * stepmul : MAX_LMEM; - return debt; - } -} - -/* -** performs a basic GC step when collector is running -*/ -void luaC_step (lua_State *L) { - global_State *g = G(L); - l_mem debt = getdebt(g); /* GC deficit (be paid now) */ - if (!g->gcrunning) { /* not running? */ - luaE_setdebt(g, -GCSTEPSIZE * 10); /* avoid being called too often */ - return; - } - do { /* repeat until pause or enough "credit" (negative debt) */ - lu_mem work = singlestep(L); /* perform one single step */ - debt -= work; - } while (debt > -GCSTEPSIZE && g->gcstate != GCSpause); - if (g->gcstate == GCSpause) - setpause(g); /* pause until next cycle */ - else { - debt = (debt / g->gcstepmul) * STEPMULADJ; /* convert 'work units' to Kb */ - luaE_setdebt(g, debt); - runafewfinalizers(L); - } -} - - -/* -** Performs a full GC cycle; if 'isemergency', set a flag to avoid -** some operations which could change the interpreter state in some -** unexpected ways (running finalizers and shrinking some structures). -** Before running the collection, check 'keepinvariant'; if it is true, -** there may be some objects marked as black, so the collector has -** to sweep all objects to turn them back to white (as white has not -** changed, nothing will be collected). -*/ -void luaC_fullgc (lua_State *L, int isemergency) { - global_State *g = G(L); - lua_assert(g->gckind == KGC_NORMAL); - if (isemergency) g->gckind = KGC_EMERGENCY; /* set flag */ - if (keepinvariant(g)) { /* black objects? */ - entersweep(L); /* sweep everything to turn them back to white */ - } - /* finish any pending sweep phase to start a new cycle */ - luaC_runtilstate(L, bitmask(GCSpause)); - luaC_runtilstate(L, ~bitmask(GCSpause)); /* start new collection */ - luaC_runtilstate(L, bitmask(GCScallfin)); /* run up to finalizers */ - /* estimate must be correct after a full GC cycle */ - lua_assert(g->GCestimate == gettotalbytes(g)); - luaC_runtilstate(L, bitmask(GCSpause)); /* finish collection */ - g->gckind = KGC_NORMAL; - setpause(g); -} - -/* }====================================================== */ - - |