'nCcalls' should be local to each thread, as each thread may have its

own C stack (with LuaThreads or something similar)

lcorolib.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lcorolib.c,v 1.1 2010/06/10 21:30:26 roberto Exp roberto $
+** $Id: lcorolib.c,v 1.2 2010/07/02 11:38:13 roberto Exp roberto $
 ** Coroutine Library
 ** See Copyright Notice in lua.h
 */
@@ -28,7 +28,7 @@ static int auxresume (lua_State *L, lua_State *co, int narg) {
     return -1;  /* error flag */
   }
   lua_xmove(L, co, narg);
-  status = lua_resume(co, narg);
+  status = lua_resume(co, L, narg);
   if (status == LUA_OK || status == LUA_YIELD) {
     int nres = lua_gettop(co);
     if (!lua_checkstack(L, nres + 1)) {

ldo.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.c,v 2.97 2011/06/20 16:36:03 roberto Exp roberto $
+** $Id: ldo.c,v 2.98 2011/06/28 15:42:04 roberto Exp roberto $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
@@ -123,7 +123,7 @@ void luaD_throw (lua_State *L, int errcode) {
 
 
 int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
-  unsigned short oldnCcalls = G(L)->nCcalls;
+  unsigned short oldnCcalls = L->nCcalls;
   struct lua_longjmp lj;
   lj.status = LUA_OK;
   lj.previous = L->errorJmp;  /* chain new error handler */
@@ -132,7 +132,7 @@ int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
     (*f)(L, ud);
   );
   L->errorJmp = lj.previous;  /* restore old error handler */
-  G(L)->nCcalls = oldnCcalls;
+  L->nCcalls = oldnCcalls;
   return lj.status;
 }
 
@@ -382,18 +382,17 @@ int luaD_poscall (lua_State *L, StkId firstResult) {
 ** function position.
 */
 void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) {
-  global_State *g = G(L);
-  if (++g->nCcalls >= LUAI_MAXCCALLS) {
-    if (g->nCcalls == LUAI_MAXCCALLS)
+  if (++L->nCcalls >= LUAI_MAXCCALLS) {
+    if (L->nCcalls == LUAI_MAXCCALLS)
       luaG_runerror(L, "C stack overflow");
-    else if (g->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
+    else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
       luaD_throw(L, LUA_ERRERR);  /* error while handing stack error */
   }
   if (!allowyield) L->nny++;
   if (!luaD_precall(L, func, nResults))  /* is a Lua function? */
     luaV_execute(L);  /* call it */
   if (!allowyield) L->nny--;
-  g->nCcalls--;
+  L->nCcalls--;
   luaC_checkGC(L);
 }
 
@@ -404,7 +403,7 @@ static void finishCcall (lua_State *L) {
   lua_assert(ci->u.c.k != NULL);  /* must have a continuation */
   lua_assert(L->nny == 0);
   /* finish 'luaD_call' */
-  G(L)->nCcalls--;
+  L->nCcalls--;
   /* finish 'lua_callk' */
   adjustresults(L, ci->nresults);
   /* call continuation function */
@@ -487,7 +486,7 @@ static void resume_error (lua_State *L, const char *msg, StkId firstArg) {
 static void resume (lua_State *L, void *ud) {
   StkId firstArg = cast(StkId, ud);
   CallInfo *ci = L->ci;
-  if (G(L)->nCcalls >= LUAI_MAXCCALLS)
+  if (L->nCcalls >= LUAI_MAXCCALLS)
     resume_error(L, "C stack overflow", firstArg);
   if (L->status == LUA_OK) {  /* may be starting a coroutine */
     if (ci != &L->base_ci)  /* not in base level? */
@@ -514,19 +513,19 @@ static void resume (lua_State *L, void *ud) {
         api_checknelems(L, n);
         firstArg = L->top - n;  /* yield results come from continuation */
       }
-      G(L)->nCcalls--;  /* finish 'luaD_call' */
+      L->nCcalls--;  /* finish 'luaD_call' */
       luaD_poscall(L, firstArg);  /* finish 'luaD_precall' */
     }
     unroll(L, NULL);
   }
 }
 
 
-LUA_API int lua_resume (lua_State *L, int nargs) {
+LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) {
   int status;
   lua_lock(L);
   luai_userstateresume(L, nargs);
-  ++G(L)->nCcalls;  /* count resume */
+  L->nCcalls = (from) ? from->nCcalls + 1 : 1;
   L->nny = 0;  /* allow yields */
   api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
   status = luaD_rawrunprotected(L, resume, L->top - nargs);
@@ -546,7 +545,8 @@ LUA_API int lua_resume (lua_State *L, int nargs) {
     lua_assert(status == L->status);
   }
   L->nny = 1;  /* do not allow yields */
-  --G(L)->nCcalls;
+  L->nCcalls--;
+  lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
   lua_unlock(L);
   return status;
 }

lparser.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 2.114 2011/07/15 12:50:29 roberto Exp roberto $
+** $Id: lparser.c,v 2.115 2011/07/27 18:09:01 roberto Exp roberto $
 ** Lua Parser
 ** See Copyright Notice in lua.h
 */
@@ -328,13 +328,13 @@ static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
 
 
 static void enterlevel (LexState *ls) {
-  global_State *g = G(ls->L);
-  ++g->nCcalls;
-  checklimit(ls->fs, g->nCcalls, LUAI_MAXCCALLS, "syntax levels");
+  lua_State *L = ls->L;
+  ++L->nCcalls;
+  checklimit(ls->fs, L->nCcalls, LUAI_MAXCCALLS, "syntax levels");
 }
 
 
-#define leavelevel(ls)	(G((ls)->L)->nCcalls--)
+#define leavelevel(ls)	((ls)->L->nCcalls--)
 
 
 static void closegoto (LexState *ls, int g, Labeldesc *label) {
@@ -1144,7 +1144,7 @@ static void assignment (LexState *ls, struct LHS_assign *lh, int nvars) {
     primaryexp(ls, &nv.v);
     if (nv.v.k != VINDEXED)
       check_conflict(ls, lh, &nv.v);
-    checklimit(ls->fs, nvars, LUAI_MAXCCALLS - G(ls->L)->nCcalls,
+    checklimit(ls->fs, nvars, LUAI_MAXCCALLS - ls->L->nCcalls,
                     "variable names");
     assignment(ls, &nv, nvars+1);
   }

lstate.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.c,v 2.89 2010/12/20 19:40:07 roberto Exp roberto $
+** $Id: lstate.c,v 2.90 2011/08/09 20:58:29 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -171,6 +171,7 @@ static void preinit_state (lua_State *L, global_State *g) {
   L->ci = NULL;
   L->stacksize = 0;
   L->errorJmp = NULL;
+  L->nCcalls = 0;
   L->hook = NULL;
   L->hookmask = 0;
   L->basehookcount = 0;
@@ -237,7 +238,6 @@ LUA_API lua_State *lua_newstate (lua_Alloc f, void *ud) {
   g->currentwhite = bit2mask(WHITE0BIT, FIXEDBIT);
   L->marked = luaC_white(g);
   g->gckind = KGC_NORMAL;
-  g->nCcalls = 0;
   preinit_state(L, g);
   g->frealloc = f;
   g->ud = ud;

lstate.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.h,v 2.71 2010/12/20 19:40:07 roberto Exp roberto $
+** $Id: lstate.h,v 2.72 2011/06/02 19:31:40 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -118,7 +118,6 @@ typedef struct global_State {
   lu_mem lastmajormem;  /* memory in use after last major collection */
   stringtable strt;  /* hash table for strings */
   TValue l_registry;
-  unsigned short nCcalls;  /* number of nested C calls */
   lu_byte currentwhite;
   lu_byte gcstate;  /* state of garbage collector */
   lu_byte gckind;  /* kind of GC running */
@@ -161,6 +160,7 @@ struct lua_State {
   StkId stack;  /* stack base */
   int stacksize;
   unsigned short nny;  /* number of non-yieldable calls in stack */
+  unsigned short nCcalls;  /* number of nested C calls */
   lu_byte hookmask;
   lu_byte allowhook;
   int basehookcount;

ltests.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ltests.c,v 2.120 2011/06/24 14:36:21 roberto Exp roberto $
+** $Id: ltests.c,v 2.121 2011/07/02 15:59:17 roberto Exp roberto $
 ** Internal Module for Debugging of the Lua Implementation
 ** See Copyright Notice in lua.h
 */
@@ -1210,7 +1210,7 @@ static int runC (lua_State *L, lua_State *L1, const char *pc) {
     }
     else if EQ("resume") {
       int i = getindex;
-      status = lua_resume(lua_tothread(L1, i), getnum);
+      status = lua_resume(lua_tothread(L1, i), L, getnum);
     }
     else if EQ("pushstatus") {
       pushcode(L1, status);
@@ -1397,7 +1397,7 @@ static int coresume (lua_State *L) {
   int status;
   lua_State *co = lua_tothread(L, 1);
   luaL_argcheck(L, co, 1, "coroutine expected");
-  status = lua_resume(co, 0);
+  status = lua_resume(co, L, 0);
   if (status != LUA_OK && status != LUA_YIELD) {
     lua_pushboolean(L, 0);
     lua_insert(L, -2);

lua.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lua.h,v 1.277 2011/04/18 14:15:48 roberto Exp roberto $
+** $Id: lua.h,v 1.278 2011/07/02 16:00:15 roberto Exp roberto $
 ** Lua - A Scripting Language
 ** Lua.org, PUC-Rio, Brazil (http://www.lua.org)
 ** See Copyright Notice at the end of this file
@@ -261,7 +261,7 @@ LUA_API int (lua_dump) (lua_State *L, lua_Writer writer, void *data);
 LUA_API int  (lua_yieldk) (lua_State *L, int nresults, int ctx,
                            lua_CFunction k);
 #define lua_yield(L,n)		lua_yieldk(L, (n), 0, NULL)
-LUA_API int  (lua_resume) (lua_State *L, int narg);
+LUA_API int  (lua_resume) (lua_State *L, lua_State *from, int narg);
 LUA_API int  (lua_status) (lua_State *L);
 
 /*