From 2ae2e6408e6f6585e23f4f10ddeafdcb8cf42324 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Wed, 4 Mar 2015 10:51:55 -0300 Subject: [PATCH] avoid testing for NULL when marking objects that cannot be NULL --- lgc.c | 32 +++++++++++++++++++++----------- 1 file changed, 21 insertions(+), 11 deletions(-) diff --git a/lgc.c b/lgc.c index db4259e0..3bc0740b 100644 --- a/lgc.c +++ b/lgc.c @@ -1,5 +1,5 @@ /* -** $Id: lgc.c,v 2.202 2015/01/16 16:54:37 roberto Exp roberto $ +** $Id: lgc.c,v 2.203 2015/03/04 13:31:21 roberto Exp roberto $ ** Garbage Collector ** See Copyright Notice in lua.h */ @@ -83,8 +83,13 @@ #define markvalue(g,o) { checkconsistency(o); \ if (valiswhite(o)) reallymarkobject(g,gcvalue(o)); } -#define markobject(g,t) \ - { if ((t) && iswhite(t)) reallymarkobject(g, obj2gco(t)); } +#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); @@ -238,7 +243,7 @@ static void reallymarkobject (global_State *g, GCObject *o) { } case LUA_TUSERDATA: { TValue uvalue; - markobject(g, gco2u(o)->metatable); /* mark its metatable */ + markobjectN(g, gco2u(o)->metatable); /* mark its metatable */ gray2black(o); g->GCmemtrav += sizeudata(gco2u(o)); getuservalue(g->mainthread, gco2u(o), &uvalue); @@ -279,7 +284,7 @@ static void reallymarkobject (global_State *g, GCObject *o) { static void markmt (global_State *g) { int i; for (i=0; i < LUA_NUMTAGS; i++) - markobject(g, g->mt[i]); + markobjectN(g, g->mt[i]); } @@ -441,7 +446,7 @@ static void traversestrongtable (global_State *g, Table *h) { static lu_mem traversetable (global_State *g, Table *h) { const char *weakkey, *weakvalue; const TValue *mode = gfasttm(g, h->metatable, TM_MODE); - markobject(g, h->metatable); + markobjectN(g, h->metatable); if (mode && ttisstring(mode) && /* is there a weak mode? */ ((weakkey = strchr(svalue(mode), 'k')), (weakvalue = strchr(svalue(mode), 'v')), @@ -461,19 +466,24 @@ static lu_mem traversetable (global_State *g, Table *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 */ - markobject(g, f->source); + 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 */ - markobject(g, f->upvalues[i].name); + markobjectN(g, f->upvalues[i].name); for (i = 0; i < f->sizep; i++) /* mark nested protos */ - markobject(g, f->p[i]); + markobjectN(g, f->p[i]); for (i = 0; i < f->sizelocvars; i++) /* mark local-variable names */ - markobject(g, f->locvars[i].varname); + markobjectN(g, f->locvars[i].varname); return sizeof(Proto) + sizeof(Instruction) * f->sizecode + sizeof(Proto *) * f->sizep + sizeof(TValue) * f->sizek + @@ -498,7 +508,7 @@ static lu_mem traverseCclosure (global_State *g, CClosure *cl) { */ static lu_mem traverseLclosure (global_State *g, LClosure *cl) { int i; - markobject(g, cl->p); /* mark its prototype */ + 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) {