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finalizers (__gc) for tables

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This commit is contained in:
Roberto Ierusalimschy 2010-11-26 12:32:31 -02:00
parent 5b33e39855
commit 9b7a12c46d
7 changed files with 63 additions and 57 deletions
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5
lapi.c
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@ -1,5 +1,5 @@
/* /*
** $Id: lapi.c,v 2.139 2010/10/25 20:31:11 roberto Exp roberto $ ** $Id: lapi.c,v 2.141 2010/11/18 19:15:00 roberto Exp roberto $
** Lua API ** Lua API
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -760,13 +760,14 @@ LUA_API int lua_setmetatable (lua_State *L, int objindex) {
hvalue(obj)->metatable = mt; hvalue(obj)->metatable = mt;
if (mt) if (mt)
luaC_objbarrierback(L, gcvalue(obj), mt); luaC_objbarrierback(L, gcvalue(obj), mt);
luaC_checkfinalizer(L, gcvalue(obj), mt);
break; break;
} }
case LUA_TUSERDATA: { case LUA_TUSERDATA: {
uvalue(obj)->metatable = mt; uvalue(obj)->metatable = mt;
if (mt) { if (mt) {
luaC_objbarrier(L, rawuvalue(obj), mt); luaC_objbarrier(L, rawuvalue(obj), mt);
luaC_checkfinalizer(L, rawuvalue(obj)); luaC_checkfinalizer(L, gcvalue(obj), mt);
} }
break; break;
} }

72
lgc.c
View File

@ -1,5 +1,5 @@
/* /*
** $Id: lgc.c,v 2.102 2010/09/03 14:14:01 roberto Exp roberto $ ** $Id: lgc.c,v 2.104 2010/11/18 19:15:00 roberto Exp roberto $
** Garbage Collector ** Garbage Collector
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -68,7 +68,7 @@
#define stringmark(s) ((void)((s) && resetbits((s)->tsv.marked, WHITEBITS))) #define stringmark(s) ((void)((s) && resetbits((s)->tsv.marked, WHITEBITS)))
#define isfinalized(u) testbit((u)->marked, FINALIZEDBIT) #define isfinalized(x) testbit(gch(x)->marked, FINALIZEDBIT)
#define checkdeadkey(n) lua_assert(!ttisdeadkey(gkey(n)) || ttisnil(gval(n))) #define checkdeadkey(n) lua_assert(!ttisdeadkey(gkey(n)) || ttisnil(gval(n)))
@ -114,12 +114,11 @@ static void removeentry (Node *n) {
*/ */
static int iscleared (const TValue *o, int iskey) { static int iscleared (const TValue *o, int iskey) {
if (!iscollectable(o)) return 0; if (!iscollectable(o)) return 0;
if (ttisstring(o)) { else if (ttisstring(o)) {
stringmark(rawtsvalue(o)); /* strings are `values', so are never weak */ stringmark(rawtsvalue(o)); /* strings are `values', so are never weak */
return 0; return 0;
} }
return iswhite(gcvalue(o)) || else return iswhite(gcvalue(o)) || (!iskey && isfinalized(gcvalue(o)));
(ttisuserdata(o) && (!iskey && isfinalized(uvalue(o))));
} }
@ -687,19 +686,18 @@ static void checkSizes (lua_State *L) {
} }
static Udata *udata2finalize (global_State *g) { static GCObject *udata2finalize (global_State *g) {
GCObject *o = g->tobefnz; /* get first element */ GCObject *o = g->tobefnz; /* get first element */
Udata *u = rawgco2u(o); lua_assert(isfinalized(o));
lua_assert(isfinalized(&u->uv));
lua_assert(!isold(o)); lua_assert(!isold(o));
g->tobefnz = u->uv.next; /* remove it from 'tobefnz' list */ g->tobefnz = gch(o)->next; /* remove it from 'tobefnz' list */
u->uv.next = g->allgc; /* return it to 'allgc' list */ gch(o)->next = g->allgc; /* return it to 'allgc' list */
g->allgc = o; g->allgc = o;
resetbit(u->uv.marked, SEPARATED); /* mark that it is not in 'tobefnz' */ resetbit(gch(o)->marked, SEPARATED); /* mark that it is not in 'tobefnz' */
resetoldbit(o); /* see MOVE OLD rule */ resetoldbit(o); /* see MOVE OLD rule */
if (!keepinvariant(g)) /* not keeping invariant? */ if (!keepinvariant(g)) /* not keeping invariant? */
makewhite(g, o); /* "sweep" object */ makewhite(g, o); /* "sweep" object */
return u; return o;
} }
@ -711,8 +709,10 @@ static void dothecall (lua_State *L, void *ud) {
static void GCTM (lua_State *L, int propagateerrors) { static void GCTM (lua_State *L, int propagateerrors) {
global_State *g = G(L); global_State *g = G(L);
Udata *udata = udata2finalize(g); const TValue *tm;
const TValue *tm = gfasttm(g, udata->uv.metatable, TM_GC); TValue v;
setgcovalue(L, &v, udata2finalize(g));
tm = luaT_gettmbyobj(L, &v, TM_GC);
if (tm != NULL && ttisfunction(tm)) { /* is there a finalizer? */ if (tm != NULL && ttisfunction(tm)) { /* is there a finalizer? */
int status; int status;
lu_byte oldah = L->allowhook; lu_byte oldah = L->allowhook;
@ -720,7 +720,7 @@ static void GCTM (lua_State *L, int propagateerrors) {
L->allowhook = 0; /* stop debug hooks during GC tag method */ L->allowhook = 0; /* stop debug hooks during GC tag method */
stopgc(g); /* avoid GC steps */ stopgc(g); /* avoid GC steps */
setobj2s(L, L->top, tm); /* push finalizer... */ setobj2s(L, L->top, tm); /* push finalizer... */
setuvalue(L, L->top+1, udata); /* ... and its argument */ setobj2s(L, L->top + 1, &v); /* ... and its argument */
L->top += 2; /* and (next line) call the finalizer */ L->top += 2; /* and (next line) call the finalizer */
status = luaD_pcall(L, dothecall, NULL, savestack(L, L->top - 2), 0); status = luaD_pcall(L, dothecall, NULL, savestack(L, L->top - 2), 0);
L->allowhook = oldah; /* restore hooks */ L->allowhook = oldah; /* restore hooks */
@ -738,25 +738,25 @@ static void GCTM (lua_State *L, int propagateerrors) {
/* /*
** move all unreachable udata that need finalization from list 'udgc' to ** move all unreachable objects that need finalization from list 'finobj'
** list 'tobefnz' ** to list 'tobefnz'
*/ */
void luaC_separateudata (lua_State *L, int all) { void luaC_separateudata (lua_State *L, int all) {
global_State *g = G(L); global_State *g = G(L);
GCObject **p = &g->udgc; GCObject **p = &g->finobj;
GCObject *curr; GCObject *curr;
GCObject **lastnext = &g->tobefnz; GCObject **lastnext = &g->tobefnz;
/* find last 'next' field in 'tobefnz' list (to add elements in its end) */ /* find last 'next' field in 'tobefnz' list (to add elements in its end) */
while (*lastnext != NULL) while (*lastnext != NULL)
lastnext = &gch(*lastnext)->next; lastnext = &gch(*lastnext)->next;
while ((curr = *p) != NULL) { /* traverse all finalizable objects */ while ((curr = *p) != NULL) { /* traverse all finalizable objects */
lua_assert(gch(curr)->tt == LUA_TUSERDATA && !isfinalized(gco2u(curr))); lua_assert(!isfinalized(curr));
lua_assert(testbit(gch(curr)->marked, SEPARATED)); lua_assert(testbit(gch(curr)->marked, SEPARATED));
if (!(all || iswhite(curr))) /* not being collected? */ if (!(all || iswhite(curr))) /* not being collected? */
p = &gch(curr)->next; /* don't bother with it */ p = &gch(curr)->next; /* don't bother with it */
else { else {
l_setbit(gch(curr)->marked, FINALIZEDBIT); /* won't be finalized again */ l_setbit(gch(curr)->marked, FINALIZEDBIT); /* won't be finalized again */
*p = gch(curr)->next; /* remove 'curr' from 'udgc' list */ *p = gch(curr)->next; /* remove 'curr' from 'finobj' list */
gch(curr)->next = *lastnext; /* link at the end of 'tobefnz' list */ gch(curr)->next = *lastnext; /* link at the end of 'tobefnz' list */
*lastnext = curr; *lastnext = curr;
lastnext = &gch(curr)->next; lastnext = &gch(curr)->next;
@ -766,23 +766,23 @@ void luaC_separateudata (lua_State *L, int all) {
/* /*
** if userdata 'u' has a finalizer, remove it from 'allgc' list (must ** if object 'o' has a finalizer, remove it from 'allgc' list (must
** search the list to find it) and link it in 'udgc' list. ** search the list to find it) and link it in 'finobj' list.
*/ */
void luaC_checkfinalizer (lua_State *L, Udata *u) { void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
global_State *g = G(L); global_State *g = G(L);
if (testbit(u->uv.marked, SEPARATED) || /* udata is already separated... */ if (testbit(gch(o)->marked, SEPARATED) || /* obj. is already separated... */
isfinalized(&u->uv) || /* ... or is finalized... */ isfinalized(o) || /* ... or is finalized... */
gfasttm(g, u->uv.metatable, TM_GC) == NULL) /* or has no finalizer? */ gfasttm(g, mt, TM_GC) == NULL) /* or has no finalizer? */
return; /* nothing to be done */ return; /* nothing to be done */
else { /* move 'u' to 'udgc' list */ else { /* move 'o' to 'finobj' list */
GCObject **p; GCObject **p;
for (p = &g->allgc; *p != obj2gco(u); p = &gch(*p)->next) ; for (p = &g->allgc; *p != o; p = &gch(*p)->next) ;
*p = u->uv.next; /* remove 'u' from root list */ *p = gch(o)->next; /* remove 'o' from root list */
u->uv.next = g->udgc; /* link it in list 'udgc' */ gch(o)->next = g->finobj; /* link it in list 'finobj' */
g->udgc = obj2gco(u); g->finobj = o;
l_setbit(u->uv.marked, SEPARATED); /* mark it as such */ l_setbit(gch(o)->marked, SEPARATED); /* mark it as such */
resetoldbit(obj2gco(u)); /* see MOVE OLD rule */ resetoldbit(o); /* see MOVE OLD rule */
} }
} }
@ -837,8 +837,8 @@ void luaC_freeallobjects (lua_State *L) {
/* following "white" makes all objects look dead */ /* following "white" makes all objects look dead */
g->currentwhite = WHITEBITS; g->currentwhite = WHITEBITS;
g->gckind = KGC_NORMAL; g->gckind = KGC_NORMAL;
sweepwholelist(L, &g->udgc); sweepwholelist(L, &g->finobj);
lua_assert(g->udgc == NULL); lua_assert(g->finobj == NULL);
sweepwholelist(L, &g->allgc); sweepwholelist(L, &g->allgc);
lua_assert(g->allgc == NULL); lua_assert(g->allgc == NULL);
for (i = 0; i < g->strt.size; i++) /* free all string lists */ for (i = 0; i < g->strt.size; i++) /* free all string lists */
@ -905,7 +905,7 @@ static l_mem singlestep (lua_State *L) {
return GCSWEEPCOST; return GCSWEEPCOST;
} }
else { /* no more strings to sweep */ else { /* no more strings to sweep */
g->sweepgc = &g->udgc; /* prepare to sweep userdata */ g->sweepgc = &g->finobj; /* prepare to sweep finalizable objects */
g->gcstate = GCSsweepudata; g->gcstate = GCSsweepudata;
return 0; return 0;
} }

4
lgc.h
View File

@ -1,5 +1,5 @@
/* /*
** $Id: lgc.h,v 2.43 2010/06/07 16:55:34 roberto Exp roberto $ ** $Id: lgc.h,v 2.45 2010/11/18 19:15:00 roberto Exp $
** Garbage Collector ** Garbage Collector
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -137,7 +137,7 @@ LUAI_FUNC GCObject *luaC_newobj (lua_State *L, int tt, size_t sz,
LUAI_FUNC void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v); LUAI_FUNC void luaC_barrier_ (lua_State *L, GCObject *o, GCObject *v);
LUAI_FUNC void luaC_barrierback_ (lua_State *L, GCObject *o); LUAI_FUNC void luaC_barrierback_ (lua_State *L, GCObject *o);
LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c); LUAI_FUNC void luaC_barrierproto_ (lua_State *L, Proto *p, Closure *c);
LUAI_FUNC void luaC_checkfinalizer (lua_State *L, Udata *u); LUAI_FUNC void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt);
LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv); LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv);
LUAI_FUNC void luaC_changemode (lua_State *L, int mode); LUAI_FUNC void luaC_changemode (lua_State *L, int mode);

6
lobject.h
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@ -1,5 +1,5 @@
/* /*
** $Id: lobject.h,v 2.41 2010/06/04 13:25:10 roberto Exp roberto $ ** $Id: lobject.h,v 2.42 2010/07/26 15:53:23 roberto Exp roberto $
** Type definitions for Lua objects ** Type definitions for Lua objects
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -153,6 +153,10 @@ typedef struct lua_TValue {
#define setbvalue(obj,x) \ #define setbvalue(obj,x) \
{ TValue *i_o=(obj); i_o->value_.b=(x); i_o->tt_=LUA_TBOOLEAN; } { TValue *i_o=(obj); i_o->value_.b=(x); i_o->tt_=LUA_TBOOLEAN; }
#define setgcovalue(L,obj,x) \
{ TValue *i_o=(obj); GCObject *i_g=(x); \
i_o->value_.gc=i_g; i_o->tt_=gch(i_g)->tt; }
#define setsvalue(L,obj,x) \ #define setsvalue(L,obj,x) \
{ TValue *i_o=(obj); \ { TValue *i_o=(obj); \
i_o->value_.gc=cast(GCObject *, (x)); i_o->tt_=LUA_TSTRING; \ i_o->value_.gc=cast(GCObject *, (x)); i_o->tt_=LUA_TSTRING; \

4
lstate.c
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@ -1,5 +1,5 @@
/* /*
** $Id: lstate.c,v 2.85 2010/04/30 18:36:22 roberto Exp roberto $ ** $Id: lstate.c,v 2.86 2010/09/03 14:14:01 roberto Exp roberto $
** Global State ** Global State
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -252,7 +252,7 @@ LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
g->version = lua_version(NULL); g->version = lua_version(NULL);
g->gcstate = GCSpause; g->gcstate = GCSpause;
g->allgc = NULL; g->allgc = NULL;
g->udgc = NULL; g->finobj = NULL;
g->tobefnz = NULL; g->tobefnz = NULL;
g->gray = g->grayagain = NULL; g->gray = g->grayagain = NULL;
g->weak = g->ephemeron = g->allweak = NULL; g->weak = g->ephemeron = g->allweak = NULL;

8
lstate.h
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@ -1,5 +1,5 @@
/* /*
** $Id: lstate.h,v 2.67 2010/09/30 17:21:31 roberto Exp roberto $ ** $Id: lstate.h,v 2.68 2010/10/29 17:52:46 roberto Exp roberto $
** Global State ** Global State
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -32,9 +32,9 @@
** when traversing the respective threads, but the thread may already be ** when traversing the respective threads, but the thread may already be
** dead, while the upvalue is still accessible through closures.) ** dead, while the upvalue is still accessible through closures.)
** **
** Userdata with finalizers are kept in the list g->udgc. ** Objects with finalizers are kept in the list g->finobj.
** **
** The list g->tobefnz links all userdata being finalized. ** The list g->tobefnz links all objects being finalized.
*/ */
@ -125,7 +125,7 @@ typedef struct global_State {
lu_byte gckind; /* kind of GC running */ lu_byte gckind; /* kind of GC running */
int sweepstrgc; /* position of sweep in `strt' */ int sweepstrgc; /* position of sweep in `strt' */
GCObject *allgc; /* list of all collectable objects */ GCObject *allgc; /* list of all collectable objects */
GCObject *udgc; /* list of collectable userdata with finalizers */ GCObject *finobj; /* list of collectable objects with finalizers */
GCObject **sweepgc; /* current position of sweep */ GCObject **sweepgc; /* current position of sweep */
GCObject *gray; /* list of gray objects */ GCObject *gray; /* list of gray objects */
GCObject *grayagain; /* list of objects to be traversed atomically */ GCObject *grayagain; /* list of objects to be traversed atomically */

21
ltests.c
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@ -1,5 +1,5 @@
/* /*
** $Id: ltests.c,v 2.112 2010/07/28 15:51:59 roberto Exp roberto $ ** $Id: ltests.c,v 2.113 2010/11/16 17:43:29 roberto Exp roberto $
** Internal Module for Debugging of the Lua Implementation ** Internal Module for Debugging of the Lua Implementation
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -429,20 +429,21 @@ int lua_checkmemory (lua_State *L) {
checkobject(g, o); checkobject(g, o);
lua_assert(!testbit(o->gch.marked, SEPARATED)); lua_assert(!testbit(o->gch.marked, SEPARATED));
} }
/* check 'udgc' list */ /* check 'finobj' list */
checkold(g, g->udgc); checkold(g, g->finobj);
for (o = g->udgc; o != NULL; o = gch(o)->next) { for (o = g->finobj; o != NULL; o = gch(o)->next) {
lua_assert(gch(o)->tt == LUA_TUSERDATA && lua_assert(!isdead(g, o) && testbit(o->gch.marked, SEPARATED));
!isdead(g, o) && lua_assert(gch(o)->tt == LUA_TUSERDATA ||
testbit(o->gch.marked, SEPARATED)); gch(o)->tt == LUA_TTABLE);
checkobject(g, o); checkobject(g, o);
} }
/* check 'tobefnz' list */ /* check 'tobefnz' list */
checkold(g, g->tobefnz); checkold(g, g->tobefnz);
for (o = g->tobefnz; o != NULL; o = gch(o)->next) { for (o = g->tobefnz; o != NULL; o = gch(o)->next) {
lua_assert(gch(o)->tt == LUA_TUSERDATA); lua_assert(!iswhite(o));
lua_assert(isblack(o)); lua_assert(!isdead(g, o) && testbit(o->gch.marked, SEPARATED));
lua_assert(testbit(o->gch.marked, SEPARATED)); lua_assert(gch(o)->tt == LUA_TUSERDATA ||
gch(o)->tt == LUA_TTABLE);
} }
/* check 'uvhead' list */ /* check 'uvhead' list */
for (uv = g->uvhead.u.l.next; uv != &g->uvhead; uv = uv->u.l.next) { for (uv = g->uvhead.u.l.next; uv != &g->uvhead; uv = uv->u.l.next) {