mirror of https://github.com/rusefi/lua.git
simpler solution for finalizing udata
This commit is contained in:
Roberto Ierusalimschy
parent
5023aaee0a
commit
ca2ceef659
105
lgc.c
105
lgc.c
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@ -1,5 +1,5 @@
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/*
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** $Id: lgc.c,v 1.129 2002/03/05 16:22:54 roberto Exp roberto $
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** $Id: lgc.c,v 1.130 2002/03/07 18:14:29 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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@ -27,7 +27,6 @@ typedef struct GCState {
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} GCState;
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/* mark a string; marks larger than 1 cannot be changed */
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#define strmark(s) {if ((s)->tsv.marked == 0) (s)->tsv.marked = 1;}
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@ -37,6 +36,9 @@ typedef struct GCState {
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#define markud(u) (u->uv.len |= 1)
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#define unmarkud(u) (u->uv.len &= (~(size_t)1))
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#define isfinalized(u) (u->uv.len & 2)
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#define markfinalized(u) (u->uv.len |= 2)
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/* mark tricks for upvalues (assume that open upvalues are always marked) */
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#define isupvalmarked(uv) ((uv)->v != &(uv)->value)
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@ -97,10 +99,17 @@ static void marktable (GCState *st, Table *h) {
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if (!ismarked(h)) {
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h->mark = st->tmark; /* chain it for later traversal */
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st->tmark = h;
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marktable(st, h->metatable);
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}
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}
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static void markudata (GCState *st, Udata *u) {
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markud(u);
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marktable(st, u->uv.metatable);
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}
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static void reallymarkobject (GCState *st, TObject *o) {
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switch (ttype(o)) {
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case LUA_TSTRING:
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@ -108,7 +117,7 @@ static void reallymarkobject (GCState *st, TObject *o) {
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break;
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case LUA_TUSERDATA:
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if (!isudmarked(uvalue(o)))
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markud(uvalue(o));
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markudata(st, uvalue(o));
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break;
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case LUA_TFUNCTION:
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markclosure(st, clvalue(o));
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@ -156,12 +165,33 @@ static void markstacks (GCState *st) {
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}
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static void markudet (GCState *st) {
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static void marktmu (GCState *st) {
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Udata *u;
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for (u = G(st->L)->rootudata; u; u = u->uv.next)
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marktable(st, u->uv.metatable);
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for (u = G(st->L)->tmudata; u; u = u->uv.next)
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marktable(st, u->uv.metatable);
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markudata(st, u);
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}
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/* move `dead' udata that need finalization to list `tmudata' */
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static void separateudata (lua_State *L) {
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Udata **p = &G(L)->rootudata;
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Udata *curr;
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Udata *collected = NULL; /* to collect udata with gc event */
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Udata **lastcollected = &collected;
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while ((curr = *p) != NULL) {
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if (isudmarked(curr) || isfinalized(curr) ||
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(fasttm(L, curr->uv.metatable, TM_GC) == NULL))
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p = &curr->uv.next;
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else { /* must call its gc method */
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*p = curr->uv.next;
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curr->uv.next = NULL; /* link `curr' at the end of `collected' list */
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*lastcollected = curr;
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lastcollected = &curr->uv.next;
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}
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}
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/* insert collected udata with gc event into `tmudata' list */
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*lastcollected = G(L)->tmudata;
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G(L)->tmudata = collected;
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}
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@ -208,7 +238,6 @@ static void markall (GCState *st) {
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lua_assert(hvalue(defaultmeta(st->L))->flags == cast(unsigned short, ~0));
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/* table is unchanged */
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markstacks(st); /* mark all stacks */
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markudet(st); /* mark userdata's meta tables */
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while (st->tmark) { /* traverse marked tables */
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Table *h = st->tmark; /* get first table from list */
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st->tmark = h->mark; /* remove it from list */
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@ -322,11 +351,10 @@ static void collecttable (lua_State *L) {
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}
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static void collectudata (lua_State *L) {
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Udata **p = &G(L)->rootudata;
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Udata *curr;
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Udata *collected = NULL; /* to collect udata with gc event */
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Udata **lastcollected = &collected;
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while ((curr = *p) != NULL) {
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if (isudmarked(curr)) {
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unmarkud(curr);
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@ -334,18 +362,11 @@ static void collectudata (lua_State *L) {
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}
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else {
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*p = curr->uv.next;
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if (fasttm(L, curr->uv.metatable, TM_GC) != NULL) { /* gc event? */
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curr->uv.next = NULL; /* link `curr' at the end of `collected' list */
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*lastcollected = curr;
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lastcollected = &curr->uv.next;
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}
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else /* no gc event; delete udata */
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luaM_free(L, curr, sizeudata(curr->uv.len));
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lua_assert(isfinalized(curr) ||
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fasttm(L, curr->uv.metatable, TM_GC) == NULL);
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luaM_free(L, curr, sizeudata(curr->uv.len & (~(size_t)3)));
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}
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}
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/* insert collected udata with gc event into `tmudata' list */
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*lastcollected = G(L)->tmudata;
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G(L)->tmudata = collected;
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}
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@ -395,44 +416,27 @@ static void do1gcTM (lua_State *L, Udata *udata) {
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}
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static void unprotectedcallGCTM (lua_State *L, void *pu) {
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luaD_checkstack(L, 3);
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L->top++; /* reserve space to keep udata while runs its gc method */
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while (G(L)->tmudata != NULL) {
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Udata *udata = G(L)->tmudata;
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G(L)->tmudata = udata->uv.next; /* remove udata from list */
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*(Udata **)pu = udata; /* keep a reference to it (in case of errors) */
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setuvalue(L->top - 1, udata); /* and on stack (in case of recursive GC) */
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udata->uv.next = G(L)->rootudata; /* resurect it */
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G(L)->rootudata = udata;
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do1gcTM(L, udata);
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/* mark udata as finalized (default meta table) */
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uvalue(L->top-1)->uv.metatable = hvalue(defaultmeta(L));
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unmarkud(uvalue(L->top-1));
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}
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L->top--;
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}
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static void callGCTM (lua_State *L) {
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int oldah = L->allowhooks;
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L->allowhooks = 0; /* stop debug hooks during GC tag methods */
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L->top++; /* reserve space to keep udata while runs its gc method */
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while (G(L)->tmudata != NULL) {
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Udata *udata;
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if (luaD_runprotected(L, unprotectedcallGCTM, &udata) != 0) {
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/* `udata' generated an error during its gc */
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/* mark it as finalized (default meta table) */
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udata->uv.metatable = hvalue(defaultmeta(L));
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}
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Udata *udata = G(L)->tmudata;
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G(L)->tmudata = udata->uv.next; /* remove udata from `tmudata' */
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udata->uv.next = G(L)->rootudata; /* return it to `root' list */
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G(L)->rootudata = udata;
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setuvalue(L->top - 1, udata); /* keep a reference to it */
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unmarkud(udata);
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markfinalized(udata);
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do1gcTM(L, udata);
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}
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L->top--;
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L->allowhooks = oldah; /* restore hooks */
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}
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void luaC_callallgcTM (lua_State *L) {
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lua_assert(G(L)->tmudata == NULL);
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G(L)->tmudata = G(L)->rootudata; /* all udata must be collected */
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G(L)->rootudata = NULL;
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separateudata(L);
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callGCTM(L); /* call their GC tag methods */
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}
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@ -452,7 +456,10 @@ void luaC_collectgarbage (lua_State *L) {
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st.L = L;
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st.tmark = NULL;
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st.toclear = NULL;
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markall(&st);
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markall(&st); /* mark all reachable objects */
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separateudata(L); /* separate userdata to be preserved */
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marktmu(&st); /* mark `preserved' userdata */
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markall(&st); /* remark */
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cleartables(st.toclear);
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luaC_collect(L, 0);
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checkMbuffer(L);
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