Update lua plugin to 5.2.3

Prior to this patch the Lua plugin used version 5.1.4. This change
reduces the number of modifications in the Lua source using some new
defines and because the upstream source is now more flexible.

Unless otherwise stated, l*.[ch] files are taken unmodified from the
upstream lua-5.2.3.

fscanf.c:
file descriptors in rockbox are just ints, they are hidden behind a
void* now so liolib requires less modifications. fscanf is updated to
use void* too.

getc.c: this is a new file required for getc implementation in lauxlib.c

lauxlib.c: LoadF replaced FILE* with int, the rockbox file
descriptor int are cast to FILE* (actually void* due to typedef).
getc uses the PREFIX version. stdin is not used, as per 5.1.4.

lbaselib.c: now uses strspn in the number parsing. print uses DEBUGF now
rather than being commented out.

lbitlib.c: use the built-in version from 5.2.3 rather than Reuben
Thomas's external library. Backwards compatible and adds some new bit
operations.

ldo.c: the LUAI_THROW/TRY defines are now in the core lua code, so have
been removed from rockconf.h

liolib.c: here the implementation has changed to use the LStream from
the original source, and cast the FILE* pointers to int. This has
reduced the number of modifications from the upstream version.

llex.c: the only change from upstream is to remove the locale include.

lmathlib.c: updated from the 5.2.3 version and re-applied the changes
that were made vs 5.1.4 for random numbers and to remove unsupported
float functions.

loadlib.c: upstream version, with the 5.1.4 changes for missing
functions.

lobject.c: upstream version, with ctype.h added and sprintf changed to
snprintf.

loslib.c: upstream version with locale.h removed and 5.1.4 changes for
unsupportable functions.

lstrlib.c: sprintf changed to snprintf.

ltable.c: upstream with the hashnum function from 5.1.4 to avoid frexp
in luai_hashnum.

luaconf.h: updated to 5.2.3 version, restored relevant parts from the
original 5.1.4 configuration. The COMPAT defines that are no longer
available are not included.

lundump.c: VERSION macro conflicts with the core Rockbox equivalent.

rocklib.c: luaL_reg is no longer available, replaced by luaL_Reg
equivalent. Moved checkboolean/optboolean functions to this file and out
of core lua files. luaL_getn is no longer available, replaced by
luaL_rawlen. luaL_register is deprecated, use the newlib/setfuncs
replacements. rli_init has to be called before setting up the newlib to
avoid overwriting the rb table.

rocklib_aux.pl: use rli_checkboolean from rocklib.c.

rocklua.c: new default bits library used, update the library loading
code with idiomatic 5.2 code.

strcspn.c: no longer needed, but strspn.c is required for strspn in
lbaselib.c

Change-Id: I0c7945c755f79083afe98ec117e1e8cf13de2651
Reviewed-on: http://gerrit.rockbox.org/774
Tested: Richard Quirk <richard.quirk@gmail.com>
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>

1 files changed, 290 insertions, 335 deletions

diff --git a/apps/plugins/lua/ldebug.c b/apps/plugins/lua/ldebug.c
index 50ad3d3803..20d663efff 100644
--- a/apps/plugins/lua/ldebug.c
+++ b/apps/plugins/lua/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 2.29.1.6 2008/05/08 16:56:26 roberto Exp $
+** $Id: ldebug.c,v 2.90.1.3 2013/05/16 16:04:15 roberto Exp $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
@@ -30,23 +30,20 @@
 
 
 
+#define noLuaClosure(f)         ((f) == NULL || (f)->c.tt == LUA_TCCL)
+
+
 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
 
 
-static int currentpc (lua_State *L, CallInfo *ci) {
-  if (!isLua(ci)) return -1;  /* function is not a Lua function? */
-  if (ci == L->ci)
-    ci->savedpc = L->savedpc;
-  return pcRel(ci->savedpc, ci_func(ci)->l.p);
+static int currentpc (CallInfo *ci) {
+  lua_assert(isLua(ci));
+  return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
 }
 
 
-static int currentline (lua_State *L, CallInfo *ci) {
-  int pc = currentpc(L, ci);
-  if (pc < 0)
-    return -1;  /* only active lua functions have current-line information */
-  else
-    return getline(ci_func(ci)->l.p, pc);
+static int currentline (CallInfo *ci) {
+  return getfuncline(ci_func(ci)->p, currentpc(ci));
 }
 
 
@@ -58,6 +55,8 @@ LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
     mask = 0;
     func = NULL;
   }
+  if (isLua(L->ci))
+    L->oldpc = L->ci->u.l.savedpc;
   L->hook = func;
   L->basehookcount = count;
   resethookcount(L);
@@ -84,19 +83,13 @@ LUA_API int lua_gethookcount (lua_State *L) {
 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
   int status;
   CallInfo *ci;
+  if (level < 0) return 0;  /* invalid (negative) level */
   lua_lock(L);
-  for (ci = L->ci; level > 0 && ci > L->base_ci; ci--) {
+  for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
     level--;
-    if (f_isLua(ci))  /* Lua function? */
-      level -= ci->tailcalls;  /* skip lost tail calls */
-  }
-  if (level == 0 && ci > L->base_ci) {  /* level found? */
+  if (level == 0 && ci != &L->base_ci) {  /* level found? */
     status = 1;
-    ar->i_ci = cast_int(ci - L->base_ci);
-  }
-  else if (level < 0) {  /* level is of a lost tail call? */
-    status = 1;
-    ar->i_ci = 0;
+    ar->i_ci = ci;
   }
   else status = 0;  /* no such level */
   lua_unlock(L);
@@ -104,43 +97,78 @@ LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
 }
 
 
-static Proto *getluaproto (CallInfo *ci) {
-  return (isLua(ci) ? ci_func(ci)->l.p : NULL);
+static const char *upvalname (Proto *p, int uv) {
+  TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
+  if (s == NULL) return "?";
+  else return getstr(s);
 }
 
 
-static const char *findlocal (lua_State *L, CallInfo *ci, int n) {
-  const char *name;
-  Proto *fp = getluaproto(ci);
-  if (fp && (name = luaF_getlocalname(fp, n, currentpc(L, ci))) != NULL)
-    return name;  /* is a local variable in a Lua function */
+static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
+  int nparams = clLvalue(ci->func)->p->numparams;
+  if (n >= ci->u.l.base - ci->func - nparams)
+    return NULL;  /* no such vararg */
   else {
-    StkId limit = (ci == L->ci) ? L->top : (ci+1)->func;
-    if (limit - ci->base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
-      return "(*temporary)";
+    *pos = ci->func + nparams + n;
+    return "(*vararg)";  /* generic name for any vararg */
+  }
+}
+
+
+static const char *findlocal (lua_State *L, CallInfo *ci, int n,
+                              StkId *pos) {
+  const char *name = NULL;
+  StkId base;
+  if (isLua(ci)) {
+    if (n < 0)  /* access to vararg values? */
+      return findvararg(ci, -n, pos);
+    else {
+      base = ci->u.l.base;
+      name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
+    }
+  }
+  else
+    base = ci->func + 1;
+  if (name == NULL) {  /* no 'standard' name? */
+    StkId limit = (ci == L->ci) ? L->top : ci->next->func;
+    if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
+      name = "(*temporary)";  /* generic name for any valid slot */
     else
-      return NULL;
+      return NULL;  /* no name */
   }
+  *pos = base + (n - 1);
+  return name;
 }
 
 
 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
-  CallInfo *ci = L->base_ci + ar->i_ci;
-  const char *name = findlocal(L, ci, n);
+  const char *name;
   lua_lock(L);
-  if (name)
-      luaA_pushobject(L, ci->base + (n - 1));
+  if (ar == NULL) {  /* information about non-active function? */
+    if (!isLfunction(L->top - 1))  /* not a Lua function? */
+      name = NULL;
+    else  /* consider live variables at function start (parameters) */
+      name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
+  }
+  else {  /* active function; get information through 'ar' */
+    StkId pos = 0;  /* to avoid warnings */
+    name = findlocal(L, ar->i_ci, n, &pos);
+    if (name) {
+      setobj2s(L, L->top, pos);
+      api_incr_top(L);
+    }
+  }
   lua_unlock(L);
   return name;
 }
 
 
 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
-  CallInfo *ci = L->base_ci + ar->i_ci;
-  const char *name = findlocal(L, ci, n);
+  StkId pos = 0;  /* to avoid warnings */
+  const char *name = findlocal(L, ar->i_ci, n, &pos);
   lua_lock(L);
   if (name)
-      setobjs2s(L, ci->base + (n - 1), L->top - 1);
+    setobjs2s(L, pos, L->top - 1);
   L->top--;  /* pop value */
   lua_unlock(L);
   return name;
@@ -148,55 +176,45 @@ LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 
 
 static void funcinfo (lua_Debug *ar, Closure *cl) {
-  if (cl->c.isC) {
+  if (noLuaClosure(cl)) {
     ar->source = "=[C]";
     ar->linedefined = -1;
     ar->lastlinedefined = -1;
     ar->what = "C";
   }
   else {
-    ar->source = getstr(cl->l.p->source);
-    ar->linedefined = cl->l.p->linedefined;
-    ar->lastlinedefined = cl->l.p->lastlinedefined;
+    Proto *p = cl->l.p;
+    ar->source = p->source ? getstr(p->source) : "=?";
+    ar->linedefined = p->linedefined;
+    ar->lastlinedefined = p->lastlinedefined;
     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
   }
   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 }
 
 
-static void info_tailcall (lua_Debug *ar) {
-  ar->name = ar->namewhat = "";
-  ar->what = "tail";
-  ar->lastlinedefined = ar->linedefined = ar->currentline = -1;
-  ar->source = "=(tail call)";
-  luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
-  ar->nups = 0;
-}
-
-
 static void collectvalidlines (lua_State *L, Closure *f) {
-  if (f == NULL || f->c.isC) {
+  if (noLuaClosure(f)) {
     setnilvalue(L->top);
+    api_incr_top(L);
   }
   else {
-    Table *t = luaH_new(L, 0, 0);
-    int *lineinfo = f->l.p->lineinfo;
     int i;
-    for (i=0; i<f->l.p->sizelineinfo; i++)
-      setbvalue(luaH_setnum(L, t, lineinfo[i]), 1);
-    sethvalue(L, L->top, t); 
+    TValue v;
+    int *lineinfo = f->l.p->lineinfo;
+    Table *t = luaH_new(L);  /* new table to store active lines */
+    sethvalue(L, L->top, t);  /* push it on stack */
+    api_incr_top(L);
+    setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
+    for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
+      luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
   }
-  incr_top(L);
 }
 
 
 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
-                    Closure *f, CallInfo *ci) {
+                       Closure *f, CallInfo *ci) {
   int status = 1;
-  if (f == NULL) {
-    info_tailcall(ar);
-    return status;
-  }
   for (; *what; what++) {
     switch (*what) {
       case 'S': {
@@ -204,15 +222,31 @@ static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
         break;
       }
       case 'l': {
-        ar->currentline = (ci) ? currentline(L, ci) : -1;
+        ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
         break;
       }
       case 'u': {
-        ar->nups = f->c.nupvalues;
+        ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
+        if (noLuaClosure(f)) {
+          ar->isvararg = 1;
+          ar->nparams = 0;
+        }
+        else {
+          ar->isvararg = f->l.p->is_vararg;
+          ar->nparams = f->l.p->numparams;
+        }
+        break;
+      }
+      case 't': {
+        ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
         break;
       }
       case 'n': {
-        ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : NULL;
+        /* calling function is a known Lua function? */
+        if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
+          ar->namewhat = getfuncname(L, ci->previous, &ar->name);
+        else
+          ar->namewhat = NULL;
         if (ar->namewhat == NULL) {
           ar->namewhat = "";  /* not found */
           ar->name = NULL;
@@ -231,29 +265,30 @@ static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
 
 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
   int status;
-  Closure *f = NULL;
-  CallInfo *ci = NULL;
+  Closure *cl;
+  CallInfo *ci;
+  StkId func;
   lua_lock(L);
   if (*what == '>') {
-    StkId func = L->top - 1;
-    luai_apicheck(L, ttisfunction(func));
+    ci = NULL;
+    func = L->top - 1;
+    api_check(L, ttisfunction(func), "function expected");
     what++;  /* skip the '>' */
-    f = clvalue(func);
     L->top--;  /* pop function */
   }
-  else if (ar->i_ci != 0) {  /* no tail call? */
-    ci = L->base_ci + ar->i_ci;
+  else {
+    ci = ar->i_ci;
+    func = ci->func;
     lua_assert(ttisfunction(ci->func));
-    f = clvalue(ci->func);
   }
-  status = auxgetinfo(L, what, ar, f, ci);
+  cl = ttisclosure(func) ? clvalue(func) : NULL;
+  status = auxgetinfo(L, what, ar, cl, ci);
   if (strchr(what, 'f')) {
-    if (f == NULL) setnilvalue(L->top);
-    else setclvalue(L, L->top, f);
-    incr_top(L);
+    setobjs2s(L, L->top, func);
+    api_incr_top(L);
   }
   if (strchr(what, 'L'))
-    collectvalidlines(L, f);
+    collectvalidlines(L, cl);
   lua_unlock(L);
   return status;
 }
@@ -261,315 +296,231 @@ LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
 
 /*
 ** {======================================================
-** Symbolic Execution and code checker
+** Symbolic Execution
 ** =======================================================
 */
 
-#define check(x)                if (!(x)) return 0;
+static const char *getobjname (Proto *p, int lastpc, int reg,
+                               const char **name);
 
-#define checkjump(pt,pc)        check(0 <= pc && pc < pt->sizecode)
 
-#define checkreg(pt,reg)        check((reg) < (pt)->maxstacksize)
-
-
-
-static int precheck (const Proto *pt) {
-  check(pt->maxstacksize <= MAXSTACK);
-  check(pt->numparams+(pt->is_vararg & VARARG_HASARG) <= pt->maxstacksize);
-  check(!(pt->is_vararg & VARARG_NEEDSARG) ||
-              (pt->is_vararg & VARARG_HASARG));
-  check(pt->sizeupvalues <= pt->nups);
-  check(pt->sizelineinfo == pt->sizecode || pt->sizelineinfo == 0);
-  check(pt->sizecode > 0 && GET_OPCODE(pt->code[pt->sizecode-1]) == OP_RETURN);
-  return 1;
-}
-
-
-#define checkopenop(pt,pc)      luaG_checkopenop((pt)->code[(pc)+1])
-
-int luaG_checkopenop (Instruction i) {
-  switch (GET_OPCODE(i)) {
-    case OP_CALL:
-    case OP_TAILCALL:
-    case OP_RETURN:
-    case OP_SETLIST: {
-      check(GETARG_B(i) == 0);
-      return 1;
+/*
+** find a "name" for the RK value 'c'
+*/
+static void kname (Proto *p, int pc, int c, const char **name) {
+  if (ISK(c)) {  /* is 'c' a constant? */
+    TValue *kvalue = &p->k[INDEXK(c)];
+    if (ttisstring(kvalue)) {  /* literal constant? */
+      *name = svalue(kvalue);  /* it is its own name */
+      return;
+    }
+    /* else no reasonable name found */
+  }
+  else {  /* 'c' is a register */
+    const char *what = getobjname(p, pc, c, name); /* search for 'c' */
+    if (what && *what == 'c') {  /* found a constant name? */
+      return;  /* 'name' already filled */
     }
-    default: return 0;  /* invalid instruction after an open call */
+    /* else no reasonable name found */
   }
+  *name = "?";  /* no reasonable name found */
 }
 
 
-static int checkArgMode (const Proto *pt, int r, enum OpArgMask mode) {
-  switch (mode) {
-    case OpArgN: check(r == 0); break;
-    case OpArgU: break;
-    case OpArgR: checkreg(pt, r); break;
-    case OpArgK:
-      check(ISK(r) ? INDEXK(r) < pt->sizek : r < pt->maxstacksize);
-      break;
-  }
-  return 1;
+static int filterpc (int pc, int jmptarget) {
+  if (pc < jmptarget)  /* is code conditional (inside a jump)? */
+    return -1;  /* cannot know who sets that register */
+  else return pc;  /* current position sets that register */
 }
 
 
-static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
+/*
+** try to find last instruction before 'lastpc' that modified register 'reg'
+*/
+static int findsetreg (Proto *p, int lastpc, int reg) {
   int pc;
-  int last;  /* stores position of last instruction that changed `reg' */
-  last = pt->sizecode-1;  /* points to final return (a `neutral' instruction) */
-  check(precheck(pt));
+  int setreg = -1;  /* keep last instruction that changed 'reg' */
+  int jmptarget = 0;  /* any code before this address is conditional */
   for (pc = 0; pc < lastpc; pc++) {
-    Instruction i = pt->code[pc];
+    Instruction i = p->code[pc];
     OpCode op = GET_OPCODE(i);
     int a = GETARG_A(i);
-    int b = 0;
-    int c = 0;
-    check(op < NUM_OPCODES);
-    checkreg(pt, a);
-    switch (getOpMode(op)) {
-      case iABC: {
-        b = GETARG_B(i);
-        c = GETARG_C(i);
-        check(checkArgMode(pt, b, getBMode(op)));
-        check(checkArgMode(pt, c, getCMode(op)));
-        break;
-      }
-      case iABx: {
-        b = GETARG_Bx(i);
-        if (getBMode(op) == OpArgK) check(b < pt->sizek);
-        break;
-      }
-      case iAsBx: {
-        b = GETARG_sBx(i);
-        if (getBMode(op) == OpArgR) {
-          int dest = pc+1+b;
-          check(0 <= dest && dest < pt->sizecode);
-          if (dest > 0) {
-            int j;
-            /* check that it does not jump to a setlist count; this
-               is tricky, because the count from a previous setlist may
-               have the same value of an invalid setlist; so, we must
-               go all the way back to the first of them (if any) */
-            for (j = 0; j < dest; j++) {
-              Instruction d = pt->code[dest-1-j];
-              if (!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0)) break;
-            }
-            /* if 'j' is even, previous value is not a setlist (even if
-               it looks like one) */
-            check((j&1) == 0);
-          }
-        }
-        break;
-      }
-    }
-    if (testAMode(op)) {
-      if (a == reg) last = pc;  /* change register `a' */
-    }
-    if (testTMode(op)) {
-      check(pc+2 < pt->sizecode);  /* check skip */
-      check(GET_OPCODE(pt->code[pc+1]) == OP_JMP);
-    }
     switch (op) {
-      case OP_LOADBOOL: {
-        if (c == 1) {  /* does it jump? */
-          check(pc+2 < pt->sizecode);  /* check its jump */
-          check(GET_OPCODE(pt->code[pc+1]) != OP_SETLIST ||
-                GETARG_C(pt->code[pc+1]) != 0);
-        }
-        break;
-      }
       case OP_LOADNIL: {
-        if (a <= reg && reg <= b)
-          last = pc;  /* set registers from `a' to `b' */
-        break;
-      }
-      case OP_GETUPVAL:
-      case OP_SETUPVAL: {
-        check(b < pt->nups);
-        break;
-      }
-      case OP_GETGLOBAL:
-      case OP_SETGLOBAL: {
-        check(ttisstring(&pt->k[b]));
-        break;
-      }
-      case OP_SELF: {
-        checkreg(pt, a+1);
-        if (reg == a+1) last = pc;
-        break;
-      }
-      case OP_CONCAT: {
-        check(b < c);  /* at least two operands */
-        break;
-      }
-      case OP_TFORLOOP: {
-        check(c >= 1);  /* at least one result (control variable) */
-        checkreg(pt, a+2+c);  /* space for results */
-        if (reg >= a+2) last = pc;  /* affect all regs above its base */
+        int b = GETARG_B(i);
+        if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
+          setreg = filterpc(pc, jmptarget);
         break;
       }
-      case OP_FORLOOP:
-      case OP_FORPREP:
-        checkreg(pt, a+3);
-        /* go through */
-      case OP_JMP: {
-        int dest = pc+1+b;
-        /* not full check and jump is forward and do not skip `lastpc'? */
-        if (reg != NO_REG && pc < dest && dest <= lastpc)
-          pc += b;  /* do the jump */
+      case OP_TFORCALL: {
+        if (reg >= a + 2)  /* affect all regs above its base */
+          setreg = filterpc(pc, jmptarget);
         break;
       }
       case OP_CALL:
       case OP_TAILCALL: {
-        if (b != 0) {
-          checkreg(pt, a+b-1);
-        }
-        c--;  /* c = num. returns */
-        if (c == LUA_MULTRET) {
-          check(checkopenop(pt, pc));
-        }
-        else if (c != 0)
-          checkreg(pt, a+c-1);
-        if (reg >= a) last = pc;  /* affect all registers above base */
+        if (reg >= a)  /* affect all registers above base */
+          setreg = filterpc(pc, jmptarget);
         break;
       }
-      case OP_RETURN: {
-        b--;  /* b = num. returns */
-        if (b > 0) checkreg(pt, a+b-1);
-        break;
-      }
-      case OP_SETLIST: {
-        if (b > 0) checkreg(pt, a + b);
-        if (c == 0) {
-          pc++;
-          check(pc < pt->sizecode - 1);
+      case OP_JMP: {
+        int b = GETARG_sBx(i);
+        int dest = pc + 1 + b;
+        /* jump is forward and do not skip `lastpc'? */
+        if (pc < dest && dest <= lastpc) {
+          if (dest > jmptarget)
+            jmptarget = dest;  /* update 'jmptarget' */
         }
         break;
       }
-      case OP_CLOSURE: {
-        int nup, j;
-        check(b < pt->sizep);
-        nup = pt->p[b]->nups;
-        check(pc + nup < pt->sizecode);
-        for (j = 1; j <= nup; j++) {
-          OpCode op1 = GET_OPCODE(pt->code[pc + j]);
-          check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
-        }
-        if (reg != NO_REG)  /* tracing? */
-          pc += nup;  /* do not 'execute' these pseudo-instructions */
+      case OP_TEST: {
+        if (reg == a)  /* jumped code can change 'a' */
+          setreg = filterpc(pc, jmptarget);
         break;
       }
-      case OP_VARARG: {
-        check((pt->is_vararg & VARARG_ISVARARG) &&
-             !(pt->is_vararg & VARARG_NEEDSARG));
-        b--;
-        if (b == LUA_MULTRET) check(checkopenop(pt, pc));
-        checkreg(pt, a+b-1);
+      default:
+        if (testAMode(op) && reg == a)  /* any instruction that set A */
+          setreg = filterpc(pc, jmptarget);
         break;
-      }
-      default: break;
     }
   }
-  return pt->code[last];
-}
-
-#undef check
-#undef checkjump
-#undef checkreg
-
-/* }====================================================== */
-
-
-int luaG_checkcode (const Proto *pt) {
-  return (symbexec(pt, pt->sizecode, NO_REG) != 0);
+  return setreg;
 }
 
 
-static const char *kname (Proto *p, int c) {
-  if (ISK(c) && ttisstring(&p->k[INDEXK(c)]))
-    return svalue(&p->k[INDEXK(c)]);
-  else
-    return "?";
-}
-
-
-static const char *getobjname (lua_State *L, CallInfo *ci, int stackpos,
+static const char *getobjname (Proto *p, int lastpc, int reg,
                                const char **name) {
-  if (isLua(ci)) {  /* a Lua function? */
-    Proto *p = ci_func(ci)->l.p;
-    int pc = currentpc(L, ci);
-    Instruction i;
-    *name = luaF_getlocalname(p, stackpos+1, pc);
-    if (*name)  /* is a local? */
-      return "local";
-    i = symbexec(p, pc, stackpos);  /* try symbolic execution */
-    lua_assert(pc != -1);
-    switch (GET_OPCODE(i)) {
-      case OP_GETGLOBAL: {
-        int g = GETARG_Bx(i);  /* global index */
-        lua_assert(ttisstring(&p->k[g]));
-        *name = svalue(&p->k[g]);
-        return "global";
-      }
+  int pc;
+  *name = luaF_getlocalname(p, reg + 1, lastpc);
+  if (*name)  /* is a local? */
+    return "local";
+  /* else try symbolic execution */
+  pc = findsetreg(p, lastpc, reg);
+  if (pc != -1) {  /* could find instruction? */
+    Instruction i = p->code[pc];
+    OpCode op = GET_OPCODE(i);
+    switch (op) {
       case OP_MOVE: {
-        int a = GETARG_A(i);
-        int b = GETARG_B(i);  /* move from `b' to `a' */
-        if (b < a)
-          return getobjname(L, ci, b, name);  /* get name for `b' */
+        int b = GETARG_B(i);  /* move from 'b' to 'a' */
+        if (b < GETARG_A(i))
+          return getobjname(p, pc, b, name);  /* get name for 'b' */
         break;
       }
+      case OP_GETTABUP:
       case OP_GETTABLE: {
         int k = GETARG_C(i);  /* key index */
-        *name = kname(p, k);
-        return "field";
+        int t = GETARG_B(i);  /* table index */
+        const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
+                         ? luaF_getlocalname(p, t + 1, pc)
+                         : upvalname(p, t);
+        kname(p, pc, k, name);
+        return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
       }
       case OP_GETUPVAL: {
-        int u = GETARG_B(i);  /* upvalue index */
-        *name = p->upvalues ? getstr(p->upvalues[u]) : "?";
+        *name = upvalname(p, GETARG_B(i));
         return "upvalue";
       }
+      case OP_LOADK:
+      case OP_LOADKX: {
+        int b = (op == OP_LOADK) ? GETARG_Bx(i)
+                                 : GETARG_Ax(p->code[pc + 1]);
+        if (ttisstring(&p->k[b])) {
+          *name = svalue(&p->k[b]);
+          return "constant";
+        }
+        break;
+      }
       case OP_SELF: {
         int k = GETARG_C(i);  /* key index */
-        *name = kname(p, k);
+        kname(p, pc, k, name);
         return "method";
       }
-      default: break;
+      default: break;  /* go through to return NULL */
     }
   }
-  return NULL;  /* no useful name found */
+  return NULL;  /* could not find reasonable name */
 }
 
 
 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
-  Instruction i;
-  if ((isLua(ci) && ci->tailcalls > 0) || !isLua(ci - 1))
-    return NULL;  /* calling function is not Lua (or is unknown) */
-  ci--;  /* calling function */
-  i = ci_func(ci)->l.p->code[currentpc(L, ci)];
-  if (GET_OPCODE(i) == OP_CALL || GET_OPCODE(i) == OP_TAILCALL ||
-      GET_OPCODE(i) == OP_TFORLOOP)
-    return getobjname(L, ci, GETARG_A(i), name);
-  else
-    return NULL;  /* no useful name can be found */
+  TMS tm;
+  Proto *p = ci_func(ci)->p;  /* calling function */
+  int pc = currentpc(ci);  /* calling instruction index */
+  Instruction i = p->code[pc];  /* calling instruction */
+  switch (GET_OPCODE(i)) {
+    case OP_CALL:
+    case OP_TAILCALL:  /* get function name */
+      return getobjname(p, pc, GETARG_A(i), name);
+    case OP_TFORCALL: {  /* for iterator */
+      *name = "for iterator";
+       return "for iterator";
+    }
+    /* all other instructions can call only through metamethods */
+    case OP_SELF:
+    case OP_GETTABUP:
+    case OP_GETTABLE: tm = TM_INDEX; break;
+    case OP_SETTABUP:
+    case OP_SETTABLE: tm = TM_NEWINDEX; break;
+    case OP_EQ: tm = TM_EQ; break;
+    case OP_ADD: tm = TM_ADD; break;
+    case OP_SUB: tm = TM_SUB; break;
+    case OP_MUL: tm = TM_MUL; break;
+    case OP_DIV: tm = TM_DIV; break;
+    case OP_MOD: tm = TM_MOD; break;
+    case OP_POW: tm = TM_POW; break;
+    case OP_UNM: tm = TM_UNM; break;
+    case OP_LEN: tm = TM_LEN; break;
+    case OP_LT: tm = TM_LT; break;
+    case OP_LE: tm = TM_LE; break;
+    case OP_CONCAT: tm = TM_CONCAT; break;
+    default:
+      return NULL;  /* else no useful name can be found */
+  }
+  *name = getstr(G(L)->tmname[tm]);
+  return "metamethod";
 }
 
+/* }====================================================== */
+
+
 
-/* only ANSI way to check whether a pointer points to an array */
+/*
+** only ANSI way to check whether a pointer points to an array
+** (used only for error messages, so efficiency is not a big concern)
+*/
 static int isinstack (CallInfo *ci, const TValue *o) {
   StkId p;
-  for (p = ci->base; p < ci->top; p++)
+  for (p = ci->u.l.base; p < ci->top; p++)
     if (o == p) return 1;
   return 0;
 }
 
 
-void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
+static const char *getupvalname (CallInfo *ci, const TValue *o,
+                                 const char **name) {
+  LClosure *c = ci_func(ci);
+  int i;
+  for (i = 0; i < c->nupvalues; i++) {
+    if (c->upvals[i]->v == o) {
+      *name = upvalname(c->p, i);
+      return "upvalue";
+    }
+  }
+  return NULL;
+}
+
+
+l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
+  CallInfo *ci = L->ci;
   const char *name = NULL;
-  const char *t = luaT_typenames[ttype(o)];
-  const char *kind = (isinstack(L->ci, o)) ?
-                         getobjname(L, L->ci, cast_int(o - L->base), &name) :
-                         NULL;
+  const char *t = objtypename(o);
+  const char *kind = NULL;
+  if (isLua(ci)) {
+    kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
+    if (!kind && isinstack(ci, o))  /* no? try a register */
+      kind = getobjname(ci_func(ci)->p, currentpc(ci),
+                        cast_int(o - ci->u.l.base), &name);
+  }
   if (kind)
     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
                 op, kind, name, t);
@@ -578,14 +529,14 @@ void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
 }
 
 
-void luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
+l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
   luaG_typeerror(L, p1, "concatenate");
 }
 
 
-void luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
+l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
   TValue temp;
   if (luaV_tonumber(p1, &temp) == NULL)
     p2 = p1;  /* first operand is wrong */
@@ -593,14 +544,13 @@ void luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
 }
 
 
-int luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
-  const char *t1 = luaT_typenames[ttype(p1)];
-  const char *t2 = luaT_typenames[ttype(p2)];
-  if (t1[2] == t2[2])
+l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
+  const char *t1 = objtypename(p1);
+  const char *t2 = objtypename(p2);
+  if (t1 == t2)
     luaG_runerror(L, "attempt to compare two %s values", t1);
   else
     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
-  return 0;
 }
 
 
@@ -608,27 +558,32 @@ static void addinfo (lua_State *L, const char *msg) {
   CallInfo *ci = L->ci;
   if (isLua(ci)) {  /* is Lua code? */
     char buff[LUA_IDSIZE];  /* add file:line information */
-    int line = currentline(L, ci);
-    luaO_chunkid(buff, getstr(getluaproto(ci)->source), LUA_IDSIZE);
+    int line = currentline(ci);
+    TString *src = ci_func(ci)->p->source;
+    if (src)
+      luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
+    else {  /* no source available; use "?" instead */
+      buff[0] = '?'; buff[1] = '\0';
+    }
     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
   }
 }
 
 
-void luaG_errormsg (lua_State *L) {
+l_noret luaG_errormsg (lua_State *L) {
   if (L->errfunc != 0) {  /* is there an error handling function? */
     StkId errfunc = restorestack(L, L->errfunc);
     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
     setobjs2s(L, L->top, L->top - 1);  /* move argument */
     setobjs2s(L, L->top - 1, errfunc);  /* push function */
-    incr_top(L);
-    luaD_call(L, L->top - 2, 1);  /* call it */
+    L->top++;
+    luaD_call(L, L->top - 2, 1, 0);  /* call it */
   }
   luaD_throw(L, LUA_ERRRUN);
 }
 
 
-void luaG_runerror (lua_State *L, const char *fmt, ...) {
+l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
   va_list argp;
   va_start(argp, fmt);
   addinfo(L, luaO_pushvfstring(L, fmt, argp));