calls to 'luaC_checkGC' in luaD_precall moved near to 'luaD_checkstack'

(which is what can need memory)

ldo.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.c,v 2.135 2014/11/11 17:13:39 roberto Exp roberto $
+** $Id: ldo.c,v 2.136 2015/03/06 19:49:50 roberto Exp roberto $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
@@ -323,6 +323,7 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
     case LUA_TCCL: {  /* C closure */
       f = clCvalue(func)->f;
      Cfunc:
+      luaC_checkGC(L);  /* stack grow uses memory */
       luaD_checkstack(L, LUA_MINSTACK);  /* ensure minimum stack size */
       ci = next_ci(L);  /* now 'enter' new function */
       ci->nresults = nresults;
@@ -330,7 +331,6 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
       ci->top = L->top + LUA_MINSTACK;
       lua_assert(ci->top <= L->stack_last);
       ci->callstatus = 0;
-      luaC_checkGC(L);  /* stack grow uses memory */
       if (L->hookmask & LUA_MASKCALL)
         luaD_hook(L, LUA_HOOKCALL, -1);
       lua_unlock(L);
@@ -344,6 +344,7 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
       StkId base;
       Proto *p = clLvalue(func)->p;
       n = cast_int(L->top - func) - 1;  /* number of real arguments */
+      luaC_checkGC(L);  /* stack grow uses memory */
       luaD_checkstack(L, p->maxstacksize);
       for (; n < p->numparams; n++)
         setnilvalue(L->top++);  /* complete missing arguments */
@@ -364,7 +365,6 @@ int luaD_precall (lua_State *L, StkId func, int nresults) {
       ci->u.l.savedpc = p->code;  /* starting point */
       ci->callstatus = CIST_LUA;
       L->top = ci->top;
-      luaC_checkGC(L);  /* stack grow uses memory */
       if (L->hookmask & LUA_MASKCALL)
         callhook(L, ci);
       return 0;
@@ -393,7 +393,7 @@ int luaD_poscall (lua_State *L, StkId firstResult) {
   }
   res = ci->func;  /* res == final position of 1st result */
   wanted = ci->nresults;
-  L->ci = ci = ci->previous;  /* back to caller */
+  L->ci = ci->previous;  /* back to caller */
   /* move results to correct place */
   for (i = wanted; i != 0 && firstResult < L->top; i--)
     setobjs2s(L, res++, firstResult++);