add support for local variable declared with attribute 'close' and 'const' for Lua 5.4.

1 files changed, 841 insertions, 0 deletions

diff --git a/src/lua/ldebug.c b/src/lua/ldebug.c
new file mode 100644
index 0000000..afdc2b7
--- /dev/null
+++ b/src/lua/ldebug.c
@@ -0,0 +1,841 @@
+/*
+** $Id: ldebug.c $
+** Debug Interface
+** See Copyright Notice in lua.h
+*/
+
+#define ldebug_c
+#define LUA_CORE
+
+#include "lprefix.h"
+
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "lua.h"
+
+#include "lapi.h"
+#include "lcode.h"
+#include "ldebug.h"
+#include "ldo.h"
+#include "lfunc.h"
+#include "lobject.h"
+#include "lopcodes.h"
+#include "lstate.h"
+#include "lstring.h"
+#include "ltable.h"
+#include "ltm.h"
+#include "lvm.h"
+
+
+
+#define noLuaClosure(f)         ((f) == NULL || (f)->c.tt == LUA_VCCL)
+
+
+/* Active Lua function (given call info) */
+#define ci_func(ci)             (clLvalue(s2v((ci)->func)))
+
+
+static const char *funcnamefromcode (lua_State *L, CallInfo *ci,
+                                    const char **name);
+
+
+static int currentpc (CallInfo *ci) {
+  lua_assert(isLua(ci));
+  return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
+}
+
+
+/*
+** Get a "base line" to find the line corresponding to an instruction.
+** For that, search the array of absolute line info for the largest saved
+** instruction smaller or equal to the wanted instruction. A special
+** case is when there is no absolute info or the instruction is before
+** the first absolute one.
+*/
+static int getbaseline (const Proto *f, int pc, int *basepc) {
+  if (f->sizeabslineinfo == 0 || pc < f->abslineinfo[0].pc) {
+    *basepc = -1;  /* start from the beginning */
+    return f->linedefined;
+  }
+  else {
+    unsigned int i;
+    if (pc >= f->abslineinfo[f->sizeabslineinfo - 1].pc)
+      i = f->sizeabslineinfo - 1;  /* instruction is after last saved one */
+    else {  /* binary search */
+      unsigned int j = f->sizeabslineinfo - 1;  /* pc < anchorlines[j] */
+      i = 0;  /* abslineinfo[i] <= pc */
+      while (i < j - 1) {
+        unsigned int m = (j + i) / 2;
+        if (pc >= f->abslineinfo[m].pc)
+          i = m;
+        else
+          j = m;
+      }
+    }
+    *basepc = f->abslineinfo[i].pc;
+    return f->abslineinfo[i].line;
+  }
+}
+
+
+/*
+** Get the line corresponding to instruction 'pc' in function 'f';
+** first gets a base line and from there does the increments until
+** the desired instruction.
+*/
+int luaG_getfuncline (const Proto *f, int pc) {
+  if (f->lineinfo == NULL)  /* no debug information? */
+    return -1;
+  else {
+    int basepc;
+    int baseline = getbaseline(f, pc, &basepc);
+    while (basepc++ < pc) {  /* walk until given instruction */
+      lua_assert(f->lineinfo[basepc] != ABSLINEINFO);
+      baseline += f->lineinfo[basepc];  /* correct line */
+    }
+    return baseline;
+  }
+}
+
+
+static int getcurrentline (CallInfo *ci) {
+  return luaG_getfuncline(ci_func(ci)->p, currentpc(ci));
+}
+
+
+/*
+** Set 'trap' for all active Lua frames.
+** This function can be called during a signal, under "reasonable"
+** assumptions. A new 'ci' is completely linked in the list before it
+** becomes part of the "active" list, and we assume that pointers are
+** atomic; see comment in next function.
+** (A compiler doing interprocedural optimizations could, theoretically,
+** reorder memory writes in such a way that the list could be
+** temporarily broken while inserting a new element. We simply assume it
+** has no good reasons to do that.)
+*/
+static void settraps (CallInfo *ci) {
+  for (; ci != NULL; ci = ci->previous)
+    if (isLua(ci))
+      ci->u.l.trap = 1;
+}
+
+
+/*
+** This function can be called during a signal, under "reasonable"
+** assumptions.
+** Fields 'oldpc', 'basehookcount', and 'hookcount' (set by
+** 'resethookcount') are for debug only, and it is no problem if they
+** get arbitrary values (causes at most one wrong hook call). 'hookmask'
+** is an atomic value. We assume that pointers are atomic too (e.g., gcc
+** ensures that for all platforms where it runs). Moreover, 'hook' is
+** always checked before being called (see 'luaD_hook').
+*/
+LUA_API void lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
+  if (func == NULL || mask == 0) {  /* turn off hooks? */
+    mask = 0;
+    func = NULL;
+  }
+  if (isLua(L->ci))
+    L->oldpc = L->ci->u.l.savedpc;
+  L->hook = func;
+  L->basehookcount = count;
+  resethookcount(L);
+  L->hookmask = cast_byte(mask);
+  if (mask)
+    settraps(L->ci);  /* to trace inside 'luaV_execute' */
+}
+
+
+LUA_API lua_Hook lua_gethook (lua_State *L) {
+  return L->hook;
+}
+
+
+LUA_API int lua_gethookmask (lua_State *L) {
+  return L->hookmask;
+}
+
+
+LUA_API int lua_gethookcount (lua_State *L) {
+  return L->basehookcount;
+}
+
+
+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 = ci->previous)
+    level--;
+  if (level == 0 && ci != &L->base_ci) {  /* level found? */
+    status = 1;
+    ar->i_ci = ci;
+  }
+  else status = 0;  /* no such level */
+  lua_unlock(L);
+  return status;
+}
+
+
+static const char *upvalname (const 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 *findvararg (CallInfo *ci, int n, StkId *pos) {
+  if (clLvalue(s2v(ci->func))->p->is_vararg) {
+    int nextra = ci->u.l.nextraargs;
+    if (n <= nextra) {
+      *pos = ci->func - nextra + (n - 1);
+      return "(vararg)";  /* generic name for any vararg */
+    }
+  }
+  return NULL;  /* no such vararg */
+}
+
+
+const char *luaG_findlocal (lua_State *L, CallInfo *ci, int n, StkId *pos) {
+  StkId base = ci->func + 1;
+  const char *name = NULL;
+  if (isLua(ci)) {
+    if (n < 0)  /* access to vararg values? */
+      return findvararg(ci, -n, pos);
+    else
+      name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
+  }
+  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? */
+      /* generic name for any valid slot */
+      name = isLua(ci) ? "(temporary)" : "(C temporary)";
+    }
+    else
+      return NULL;  /* no name */
+  }
+  if (pos)
+    *pos = base + (n - 1);
+  return name;
+}
+
+
+LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
+  const char *name;
+  lua_lock(L);
+  if (ar == NULL) {  /* information about non-active function? */
+    if (!isLfunction(s2v(L->top - 1)))  /* not a Lua function? */
+      name = NULL;
+    else  /* consider live variables at function start (parameters) */
+      name = luaF_getlocalname(clLvalue(s2v(L->top - 1))->p, n, 0);
+  }
+  else {  /* active function; get information through 'ar' */
+    StkId pos = NULL;  /* to avoid warnings */
+    name = luaG_findlocal(L, ar->i_ci, n, &pos);
+    if (name) {
+      setobjs2s(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) {
+  StkId pos = NULL;  /* to avoid warnings */
+  const char *name;
+  lua_lock(L);
+  name = luaG_findlocal(L, ar->i_ci, n, &pos);
+  if (name) {
+    setobjs2s(L, pos, L->top - 1);
+    L->top--;  /* pop value */
+  }
+  lua_unlock(L);
+  return name;
+}
+
+
+static void funcinfo (lua_Debug *ar, Closure *cl) {
+  if (noLuaClosure(cl)) {
+    ar->source = "=[C]";
+    ar->srclen = LL("=[C]");
+    ar->linedefined = -1;
+    ar->lastlinedefined = -1;
+    ar->what = "C";
+  }
+  else {
+    const Proto *p = cl->l.p;
+    if (p->source) {
+      ar->source = getstr(p->source);
+      ar->srclen = tsslen(p->source);
+    }
+    else {
+      ar->source = "=?";
+      ar->srclen = LL("=?");
+    }
+    ar->linedefined = p->linedefined;
+    ar->lastlinedefined = p->lastlinedefined;
+    ar->what = (ar->linedefined == 0) ? "main" : "Lua";
+  }
+  luaO_chunkid(ar->short_src, ar->source, ar->srclen);
+}
+
+
+static int nextline (const Proto *p, int currentline, int pc) {
+  if (p->lineinfo[pc] != ABSLINEINFO)
+    return currentline + p->lineinfo[pc];
+  else
+    return luaG_getfuncline(p, pc);
+}
+
+
+static void collectvalidlines (lua_State *L, Closure *f) {
+  if (noLuaClosure(f)) {
+    setnilvalue(s2v(L->top));
+    api_incr_top(L);
+  }
+  else {
+    int i;
+    TValue v;
+    const Proto *p = f->l.p;
+    int currentline = p->linedefined;
+    Table *t = luaH_new(L);  /* new table to store active lines */
+    sethvalue2s(L, L->top, t);  /* push it on stack */
+    api_incr_top(L);
+    setbtvalue(&v);  /* boolean 'true' to be the value of all indices */
+    for (i = 0; i < p->sizelineinfo; i++) {  /* for all lines with code */
+      currentline = nextline(p, currentline, i);
+      luaH_setint(L, t, currentline, &v);  /* table[line] = true */
+    }
+  }
+}
+
+
+static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
+  if (ci == NULL)  /* no 'ci'? */
+    return NULL;  /* no info */
+  else if (ci->callstatus & CIST_FIN) {  /* is this a finalizer? */
+    *name = "__gc";
+    return "metamethod";  /* report it as such */
+  }
+  /* calling function is a known Lua function? */
+  else if (!(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
+    return funcnamefromcode(L, ci->previous, name);
+  else return NULL;  /* no way to find a name */
+}
+
+
+static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
+                       Closure *f, CallInfo *ci) {
+  int status = 1;
+  for (; *what; what++) {
+    switch (*what) {
+      case 'S': {
+        funcinfo(ar, f);
+        break;
+      }
+      case 'l': {
+        ar->currentline = (ci && isLua(ci)) ? getcurrentline(ci) : -1;
+        break;
+      }
+      case 'u': {
+        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 = getfuncname(L, ci, &ar->name);
+        if (ar->namewhat == NULL) {
+          ar->namewhat = "";  /* not found */
+          ar->name = NULL;
+        }
+        break;
+      }
+      case 'r': {
+        if (ci == NULL || !(ci->callstatus & CIST_TRAN))
+          ar->ftransfer = ar->ntransfer = 0;
+        else {
+          ar->ftransfer = ci->u2.transferinfo.ftransfer;
+          ar->ntransfer = ci->u2.transferinfo.ntransfer;
+        }
+        break;
+      }
+      case 'L':
+      case 'f':  /* handled by lua_getinfo */
+        break;
+      default: status = 0;  /* invalid option */
+    }
+  }
+  return status;
+}
+
+
+LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
+  int status;
+  Closure *cl;
+  CallInfo *ci;
+  TValue *func;
+  lua_lock(L);
+  if (*what == '>') {
+    ci = NULL;
+    func = s2v(L->top - 1);
+    api_check(L, ttisfunction(func), "function expected");
+    what++;  /* skip the '>' */
+    L->top--;  /* pop function */
+  }
+  else {
+    ci = ar->i_ci;
+    func = s2v(ci->func);
+    lua_assert(ttisfunction(func));
+  }
+  cl = ttisclosure(func) ? clvalue(func) : NULL;
+  status = auxgetinfo(L, what, ar, cl, ci);
+  if (strchr(what, 'f')) {
+    setobj2s(L, L->top, func);
+    api_incr_top(L);
+  }
+  if (strchr(what, 'L'))
+    collectvalidlines(L, cl);
+  lua_unlock(L);
+  return status;
+}
+
+
+/*
+** {======================================================
+** Symbolic Execution
+** =======================================================
+*/
+
+static const char *getobjname (const Proto *p, int lastpc, int reg,
+                               const char **name);
+
+
+/*
+** Find a "name" for the constant 'c'.
+*/
+static void kname (const Proto *p, int c, const char **name) {
+  TValue *kvalue = &p->k[c];
+  *name = (ttisstring(kvalue)) ? svalue(kvalue) : "?";
+}
+
+
+/*
+** Find a "name" for the register 'c'.
+*/
+static void rname (const Proto *p, int pc, int c, const char **name) {
+  const char *what = getobjname(p, pc, c, name); /* search for 'c' */
+  if (!(what && *what == 'c'))  /* did not find a constant name? */
+    *name = "?";
+}
+
+
+/*
+** Find a "name" for a 'C' value in an RK instruction.
+*/
+static void rkname (const Proto *p, int pc, Instruction i, const char **name) {
+  int c = GETARG_C(i);  /* key index */
+  if (GETARG_k(i))  /* is 'c' a constant? */
+    kname(p, c, name);
+  else  /* 'c' is a register */
+    rname(p, pc, c, name);
+}
+
+
+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 */
+}
+
+
+/*
+** Try to find last instruction before 'lastpc' that modified register 'reg'.
+*/
+static int findsetreg (const Proto *p, int lastpc, int reg) {
+  int pc;
+  int setreg = -1;  /* keep last instruction that changed 'reg' */
+  int jmptarget = 0;  /* any code before this address is conditional */
+  if (testMMMode(GET_OPCODE(p->code[lastpc])))
+    lastpc--;  /* previous instruction was not actually executed */
+  for (pc = 0; pc < lastpc; pc++) {
+    Instruction i = p->code[pc];
+    OpCode op = GET_OPCODE(i);
+    int a = GETARG_A(i);
+    int change;  /* true if current instruction changed 'reg' */
+    switch (op) {
+      case OP_LOADNIL: {  /* set registers from 'a' to 'a+b' */
+        int b = GETARG_B(i);
+        change = (a <= reg && reg <= a + b);
+        break;
+      }
+      case OP_TFORCALL: {  /* affect all regs above its base */
+        change = (reg >= a + 2);
+        break;
+      }
+      case OP_CALL:
+      case OP_TAILCALL: {  /* affect all registers above base */
+        change = (reg >= a);
+        break;
+      }
+      case OP_JMP: {  /* doesn't change registers, but changes 'jmptarget' */
+        int b = GETARG_sJ(i);
+        int dest = pc + 1 + b;
+        /* jump does not skip 'lastpc' and is larger than current one? */
+        if (dest <= lastpc && dest > jmptarget)
+          jmptarget = dest;  /* update 'jmptarget' */
+        change = 0;
+        break;
+      }
+      default:  /* any instruction that sets A */
+        change = (testAMode(op) && reg == a);
+        break;
+    }
+    if (change)
+      setreg = filterpc(pc, jmptarget);
+  }
+  return setreg;
+}
+
+
+/*
+** Check whether table being indexed by instruction 'i' is the
+** environment '_ENV'
+*/
+static const char *gxf (const Proto *p, int pc, Instruction i, int isup) {
+  int t = GETARG_B(i);  /* table index */
+  const char *name;  /* name of indexed variable */
+  if (isup)  /* is an upvalue? */
+    name = upvalname(p, t);
+  else
+    getobjname(p, pc, t, &name);
+  return (name && strcmp(name, LUA_ENV) == 0) ? "global" : "field";
+}
+
+
+static const char *getobjname (const Proto *p, int lastpc, int reg,
+                               const char **name) {
+  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 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: {
+        int k = GETARG_C(i);  /* key index */
+        kname(p, k, name);
+        return gxf(p, pc, i, 1);
+      }
+      case OP_GETTABLE: {
+        int k = GETARG_C(i);  /* key index */
+        rname(p, pc, k, name);
+        return gxf(p, pc, i, 0);
+      }
+      case OP_GETI: {
+        *name = "integer index";
+        return "field";
+      }
+      case OP_GETFIELD: {
+        int k = GETARG_C(i);  /* key index */
+        kname(p, k, name);
+        return gxf(p, pc, i, 0);
+      }
+      case OP_GETUPVAL: {
+        *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: {
+        rkname(p, pc, i, name);
+        return "method";
+      }
+      default: break;  /* go through to return NULL */
+    }
+  }
+  return NULL;  /* could not find reasonable name */
+}
+
+
+/*
+** Try to find a name for a function based on the code that called it.
+** (Only works when function was called by a Lua function.)
+** Returns what the name is (e.g., "for iterator", "method",
+** "metamethod") and sets '*name' to point to the name.
+*/
+static const char *funcnamefromcode (lua_State *L, CallInfo *ci,
+                                     const char **name) {
+  TMS tm = (TMS)0;  /* (initial value avoids warnings) */
+  const Proto *p = ci_func(ci)->p;  /* calling function */
+  int pc = currentpc(ci);  /* calling instruction index */
+  Instruction i = p->code[pc];  /* calling instruction */
+  if (ci->callstatus & CIST_HOOKED) {  /* was it called inside a hook? */
+    *name = "?";
+    return "hook";
+  }
+  switch (GET_OPCODE(i)) {
+    case OP_CALL:
+    case OP_TAILCALL:
+      return getobjname(p, pc, GETARG_A(i), name);  /* get function name */
+    case OP_TFORCALL: {  /* for iterator */
+      *name = "for iterator";
+       return "for iterator";
+    }
+    /* other instructions can do calls through metamethods */
+    case OP_SELF: case OP_GETTABUP: case OP_GETTABLE:
+    case OP_GETI: case OP_GETFIELD:
+      tm = TM_INDEX;
+      break;
+    case OP_SETTABUP: case OP_SETTABLE: case OP_SETI: case OP_SETFIELD:
+      tm = TM_NEWINDEX;
+      break;
+    case OP_MMBIN: case OP_MMBINI: case OP_MMBINK: {
+      tm = cast(TMS, GETARG_C(i));
+      break;
+    }
+    case OP_UNM: tm = TM_UNM; break;
+    case OP_BNOT: tm = TM_BNOT; break;
+    case OP_LEN: tm = TM_LEN; break;
+    case OP_CONCAT: tm = TM_CONCAT; break;
+    case OP_EQ: tm = TM_EQ; break;
+    case OP_LT: case OP_LE: case OP_LTI: case OP_LEI:
+      *name = "order";  /* '<=' can call '__lt', etc. */
+      return "metamethod";
+    case OP_CLOSE: case OP_RETURN:
+      *name = "close";
+      return "metamethod";
+    default:
+      return NULL;  /* cannot find a reasonable name */
+  }
+  *name = getstr(G(L)->tmname[tm]) + 2;
+  return "metamethod";
+}
+
+/* }====================================================== */
+
+
+
+/*
+** The subtraction of two potentially unrelated pointers is
+** not ISO C, but it should not crash a program; the subsequent
+** checks are ISO C and ensure a correct result.
+*/
+static int isinstack (CallInfo *ci, const TValue *o) {
+  StkId base = ci->func + 1;
+  ptrdiff_t i = cast(StkId, o) - base;
+  return (0 <= i && i < (ci->top - base) && s2v(base + i) == o);
+}
+
+
+/*
+** Checks whether value 'o' came from an upvalue. (That can only happen
+** with instructions OP_GETTABUP/OP_SETTABUP, which operate directly on
+** upvalues.)
+*/
+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;
+}
+
+
+static const char *varinfo (lua_State *L, const TValue *o) {
+  const char *name = NULL;  /* to avoid warnings */
+  CallInfo *ci = L->ci;
+  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(cast(StkId, o) - (ci->func + 1)), &name);
+  }
+  return (kind) ? luaO_pushfstring(L, " (%s '%s')", kind, name) : "";
+}
+
+
+l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
+  const char *t = luaT_objtypename(L, o);
+  luaG_runerror(L, "attempt to %s a %s value%s", op, t, varinfo(L, o));
+}
+
+
+l_noret luaG_forerror (lua_State *L, const TValue *o, const char *what) {
+  luaG_runerror(L, "bad 'for' %s (number expected, got %s)",
+                   what, luaT_objtypename(L, o));
+}
+
+
+l_noret luaG_concaterror (lua_State *L, const TValue *p1, const TValue *p2) {
+  if (ttisstring(p1) || cvt2str(p1)) p1 = p2;
+  luaG_typeerror(L, p1, "concatenate");
+}
+
+
+l_noret luaG_opinterror (lua_State *L, const TValue *p1,
+                         const TValue *p2, const char *msg) {
+  if (!ttisnumber(p1))  /* first operand is wrong? */
+    p2 = p1;  /* now second is wrong */
+  luaG_typeerror(L, p2, msg);
+}
+
+
+/*
+** Error when both values are convertible to numbers, but not to integers
+*/
+l_noret luaG_tointerror (lua_State *L, const TValue *p1, const TValue *p2) {
+  lua_Integer temp;
+  if (!tointegerns(p1, &temp))
+    p2 = p1;
+  luaG_runerror(L, "number%s has no integer representation", varinfo(L, p2));
+}
+
+
+l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
+  const char *t1 = luaT_objtypename(L, p1);
+  const char *t2 = luaT_objtypename(L, p2);
+  if (strcmp(t1, t2) == 0)
+    luaG_runerror(L, "attempt to compare two %s values", t1);
+  else
+    luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
+}
+
+
+/* add src:line information to 'msg' */
+const char *luaG_addinfo (lua_State *L, const char *msg, TString *src,
+                                        int line) {
+  char buff[LUA_IDSIZE];
+  if (src)
+    luaO_chunkid(buff, getstr(src), tsslen(src));
+  else {  /* no source available; use "?" instead */
+    buff[0] = '?'; buff[1] = '\0';
+  }
+  return luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
+}
+
+
+l_noret luaG_errormsg (lua_State *L) {
+  if (L->errfunc != 0) {  /* is there an error handling function? */
+    StkId errfunc = restorestack(L, L->errfunc);
+    lua_assert(ttisfunction(s2v(errfunc)));
+    setobjs2s(L, L->top, L->top - 1);  /* move argument */
+    setobjs2s(L, L->top - 1, errfunc);  /* push function */
+    L->top++;  /* assume EXTRA_STACK */
+    luaD_callnoyield(L, L->top - 2, 1);  /* call it */
+  }
+  luaD_throw(L, LUA_ERRRUN);
+}
+
+
+l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
+  CallInfo *ci = L->ci;
+  const char *msg;
+  va_list argp;
+  luaC_checkGC(L);  /* error message uses memory */
+  va_start(argp, fmt);
+  msg = luaO_pushvfstring(L, fmt, argp);  /* format message */
+  va_end(argp);
+  if (isLua(ci))  /* if Lua function, add source:line information */
+    luaG_addinfo(L, msg, ci_func(ci)->p->source, getcurrentline(ci));
+  luaG_errormsg(L);
+}
+
+
+/*
+** Check whether new instruction 'newpc' is in a different line from
+** previous instruction 'oldpc'.
+*/
+static int changedline (const Proto *p, int oldpc, int newpc) {
+  while (oldpc++ < newpc) {
+    if (p->lineinfo[oldpc] != 0)
+      return (luaG_getfuncline(p, oldpc - 1) != luaG_getfuncline(p, newpc));
+  }
+  return 0;  /* no line changes in the way */
+}
+
+
+int luaG_traceexec (lua_State *L, const Instruction *pc) {
+  CallInfo *ci = L->ci;
+  lu_byte mask = L->hookmask;
+  int counthook;
+  if (!(mask & (LUA_MASKLINE | LUA_MASKCOUNT))) {  /* no hooks? */
+    ci->u.l.trap = 0;  /* don't need to stop again */
+    return 0;  /* turn off 'trap' */
+  }
+  pc++;  /* reference is always next instruction */
+  ci->u.l.savedpc = pc;  /* save 'pc' */
+  counthook = (--L->hookcount == 0 && (mask & LUA_MASKCOUNT));
+  if (counthook)
+    resethookcount(L);  /* reset count */
+  else if (!(mask & LUA_MASKLINE))
+    return 1;  /* no line hook and count != 0; nothing to be done now */
+  if (ci->callstatus & CIST_HOOKYIELD) {  /* called hook last time? */
+    ci->callstatus &= ~CIST_HOOKYIELD;  /* erase mark */
+    return 1;  /* do not call hook again (VM yielded, so it did not move) */
+  }
+  if (!isIT(*(ci->u.l.savedpc - 1)))
+    L->top = ci->top;  /* prepare top */
+  if (counthook)
+    luaD_hook(L, LUA_HOOKCOUNT, -1, 0, 0);  /* call count hook */
+  if (mask & LUA_MASKLINE) {
+    const Proto *p = ci_func(ci)->p;
+    int npci = pcRel(pc, p);
+    if (npci == 0 ||  /* call linehook when enter a new function, */
+        pc <= L->oldpc ||  /* when jump back (loop), or when */
+        changedline(p, pcRel(L->oldpc, p), npci)) {  /* enter new line */
+      int newline = luaG_getfuncline(p, npci);
+      luaD_hook(L, LUA_HOOKLINE, newline, 0, 0);  /* call line hook */
+    }
+    L->oldpc = pc;  /* 'pc' of last call to line hook */
+  }
+  if (L->status == LUA_YIELD) {  /* did hook yield? */
+    if (counthook)
+      L->hookcount = 1;  /* undo decrement to zero */
+    ci->u.l.savedpc--;  /* undo increment (resume will increment it again) */
+    ci->callstatus |= CIST_HOOKYIELD;  /* mark that it yielded */
+    luaD_throw(L, LUA_YIELD);
+  }
+  return 1;  /* keep 'trap' on */
+}
+