mirror of https://github.com/lua/lua
try to avoid sweeping new objects created with new white (and
therefore not collectable in the current cycle)
This commit is contained in:
Roberto Ierusalimschy
parent
398811a313
commit
b36b4b521f
62
lgc.c
62
lgc.c
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@ -1,5 +1,5 @@
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/*
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** $Id: lgc.c,v 2.123 2012/05/20 20:36:44 roberto Exp roberto $
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** $Id: lgc.c,v 2.124 2012/05/21 13:18:10 roberto Exp roberto $
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** Garbage Collector
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** See Copyright Notice in lua.h
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*/
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@ -49,6 +49,7 @@
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#define workrate(x,mul) \
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((x) < MAX_INT/80 ? ((x) * 80) / mul : ((x) / mul) * 80)
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/*
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** standard negative debt for GC; a reasonable "time" to wait before
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** starting a new cycle
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@ -738,19 +739,16 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
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freeobj(L, curr); /* erase 'curr' */
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}
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else {
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if (testbits(marked, tostop))
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return NULL; /* stop sweeping this list */
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if (gch(curr)->tt == LUA_TTHREAD)
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sweepthread(L, gco2th(curr)); /* sweep thread's upvalues */
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if (testbits(marked, tostop)) {
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static GCObject *nullp = NULL;
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p = &nullp; /* stop sweeping this list */
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break;
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}
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/* update marks */
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gch(curr)->marked = cast_byte((marked & toclear) | toset);
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p = &gch(curr)->next; /* go to next element */
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}
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}
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return p;
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return (*p == NULL) ? NULL : p;
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}
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/* }====================================================== */
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@ -865,7 +863,7 @@ void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
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GCObject **p;
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GCheader *ho = gch(o);
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/* avoid removing current sweep object */
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if (g->gcstate == GCSsweep && g->sweepgc == &ho->next) {
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if (g->sweepgc == &ho->next) {
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/* step to next object in the list */
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g->sweepgc = (ho->next == NULL) ? NULL : &gch(ho->next)->next;
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}
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@ -892,6 +890,24 @@ void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
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#define sweepphases \
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(bitmask(GCSsweepstring) | bitmask(GCSsweepudata) | bitmask(GCSsweep))
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/*
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** enter first sweep phase (strings) and prepare pointers for other
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** sweep phases. The calls to 'sweeplist' attempt to make pointers
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** point to an object inside the list (instead of to the header), so
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** that the real sweep do not need to skip objects created between "now"
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** and the start of the real sweep.
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*/
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static void entersweep (lua_State *L) {
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global_State *g = G(L);
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g->gcstate = GCSsweepstring;
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lua_assert(g->sweepgc == NULL && g->sweepfin == NULL);
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g->sweepstrgc = 0; /* prepare to sweep strings, ... */
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g->sweepfin = sweeplist(L, &g->finobj, 1); /* finalizable objects, ... */
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g->sweepgc = sweeplist(L, &g->allgc, 1); /* and regular objects */
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}
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/*
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** change GC mode
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*/
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@ -907,9 +923,8 @@ void luaC_changemode (lua_State *L, int mode) {
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else { /* change to incremental mode */
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/* sweep all objects to turn them back to white
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(as white has not changed, nothing extra will be collected) */
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g->sweepstrgc = 0;
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g->gcstate = GCSsweepstring;
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g->gckind = KGC_NORMAL;
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entersweep(L);
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luaC_runtilstate(L, ~sweepphases);
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}
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}
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@ -972,9 +987,8 @@ static void atomic (lua_State *L) {
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/* clear values from resurrected weak tables */
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clearvalues(g, g->weak, origweak);
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clearvalues(g, g->allweak, origall);
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g->sweepstrgc = 0; /* prepare to sweep strings */
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g->gcstate = GCSsweepstring;
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g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */
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entersweep(L); /* prepare to sweep strings */
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/*lua_checkmemory(L);*/
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}
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@ -1010,25 +1024,22 @@ static lu_mem singlestep (lua_State *L) {
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for (i = 0; i < GCSWEEPMAX && g->sweepstrgc + i < g->strt.size; i++)
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sweepwholelist(L, &g->strt.hash[g->sweepstrgc + i]);
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g->sweepstrgc += i;
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if (g->sweepstrgc >= g->strt.size) { /* no more strings to sweep? */
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g->sweepgc = &g->finobj; /* prepare to sweep finalizable objects */
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if (g->sweepstrgc >= g->strt.size) /* no more strings to sweep? */
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g->gcstate = GCSsweepudata;
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}
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return i * GCSWEEPCOST;
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}
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case GCSsweepudata: {
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if (*g->sweepgc) {
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g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
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if (g->sweepfin) {
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g->sweepfin = sweeplist(L, g->sweepfin, GCSWEEPMAX);
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return GCSWEEPMAX*GCSWEEPCOST;
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}
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else {
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g->sweepgc = &g->allgc; /* go to next phase */
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g->gcstate = GCSsweep;
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return 0;
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}
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}
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case GCSsweep: {
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if (*g->sweepgc) {
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if (g->sweepgc) {
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g->sweepgc = sweeplist(L, g->sweepgc, GCSWEEPMAX);
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return GCSWEEPMAX*GCSWEEPCOST;
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}
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@ -1121,16 +1132,19 @@ void luaC_step (lua_State *L) {
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void luaC_fullgc (lua_State *L, int isemergency) {
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global_State *g = G(L);
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int origkind = g->gckind;
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int someblack = keepinvariant(g);
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lua_assert(origkind != KGC_EMERGENCY);
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if (!isemergency) /* do not run finalizers during emergency GC */
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if (isemergency) /* do not run finalizers during emergency GC */
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g->gckind = KGC_EMERGENCY;
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else {
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g->gckind = KGC_NORMAL;
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callallpendingfinalizers(L, 1);
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if (keepinvariant(g)) { /* marking phase? */
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}
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if (someblack) { /* may there be some black objects? */
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/* must sweep all objects to turn them back to white
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(as white has not changed, nothing will be collected) */
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g->sweepstrgc = 0;
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g->gcstate = GCSsweepstring;
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entersweep(L);
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}
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g->gckind = isemergency ? KGC_EMERGENCY : KGC_NORMAL;
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/* finish any pending sweep phase to start a new cycle */
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luaC_runtilstate(L, bitmask(GCSpause));
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/* run entire collector */
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3
lstate.c
3
lstate.c
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@ -1,5 +1,5 @@
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/*
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** $Id: lstate.c,v 2.93 2012/02/01 21:57:15 roberto Exp roberto $
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** $Id: lstate.c,v 2.94 2012/05/11 14:06:07 roberto Exp roberto $
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** Global State
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** See Copyright Notice in lua.h
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*/
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@ -292,6 +292,7 @@ LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
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g->allgc = NULL;
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g->finobj = NULL;
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g->tobefnz = NULL;
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g->sweepgc = g->sweepfin = NULL;
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g->gray = g->grayagain = NULL;
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g->weak = g->ephemeron = g->allweak = NULL;
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g->totalbytes = sizeof(LG);
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5
lstate.h
5
lstate.h
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@ -1,5 +1,5 @@
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/*
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** $Id: lstate.h,v 2.77 2012/02/01 21:57:15 roberto Exp roberto $
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** $Id: lstate.h,v 2.78 2012/05/20 20:36:44 roberto Exp roberto $
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** Global State
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** See Copyright Notice in lua.h
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*/
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@ -126,7 +126,8 @@ typedef struct global_State {
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int sweepstrgc; /* position of sweep in `strt' */
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GCObject *allgc; /* list of all collectable objects */
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GCObject *finobj; /* list of collectable objects with finalizers */
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GCObject **sweepgc; /* current position of sweep */
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GCObject **sweepgc; /* current position of sweep in list 'allgc' */
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GCObject **sweepfin; /* current position of sweep in list 'finobj' */
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GCObject *gray; /* list of gray objects */
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GCObject *grayagain; /* list of objects to be traversed atomically */
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GCObject *weak; /* list of tables with weak values */
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