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/*

** $Id: ldebug.c,v 2.88 2011/11/30 12:43:51 roberto Exp $

** Debug Interface

** See Copyright Notice in lua.h

*/

#include 

#include 

#include 

#define ldebug_c

#define LUA_CORE

#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"

static const char *getfuncname (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);

}

static int currentline (CallInfo *ci) {

  return getfuncline(ci_func(ci)->p, currentpc(ci));

}

/*

** this function can be called asynchronous (e.g. during a signal)

*/

LUA_API int 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);

  return 1;

}

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 (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) {

  int nparams = clLvalue(ci->func)->p->numparams;

  if (n >= ci->u.l.base - ci->func - nparams)

    return NULL;  /* no such vararg */

  else {

    *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;  /* no name */

  }

  *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(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) {

  StkId pos = 0;  /* to avoid warnings */

  const char *name = findlocal(L, ar->i_ci, n, &pos);

  lua_lock(L);

  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 (cl == NULL || cl->c.isC) {

    ar->source = "=[C]";

    ar->linedefined = -1;

    ar->lastlinedefined = -1;

    ar->what = "C";

  }

  else {

    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 collectvalidlines (lua_State *L, Closure *f) {

  if (f == NULL || f->c.isC) {

    setnilvalue(L->top);

    incr_top(L);

  }

  else {

    int i;

    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 */

    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 */

  }

}

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)) ? currentline(ci) : -1;

        break;

      }

      case 'u': {

        ar->nups = (f == NULL) ? 0 : f->c.nupvalues;

        if (f == NULL || f->c.isC) {

          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': {

        /* 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;

        }

        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;

  StkId func;

  lua_lock(L);

  if (*what == '>') {

    ci = NULL;

    func = L->top - 1;

    api_check(L, ttisfunction(func), "function expected");

    what++;  /* skip the '>' */

    L->top--;  /* pop function */

  }

  else {

    ci = ar->i_ci;

    func = ci->func;

    lua_assert(ttisfunction(ci->func));

  }

  cl = ttisclosure(func) ? clvalue(func) : NULL;

  status = auxgetinfo(L, what, ar, cl, ci);

  if (strchr(what, 'f')) {

    setobjs2s(L, L->top, func);

    incr_top(L);

  }

  if (strchr(what, 'L'))

    collectvalidlines(L, cl);

  lua_unlock(L);

  return status;

}

/*

** {======================================================

** Symbolic Execution

** =======================================================

*/

static const char *getobjname (Proto *p, int lastpc, int reg,

                               const char **name);

/*

** 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 */

    }

    /* else no reasonable name found */

  }

  *name = "?";  /* no reasonable name found */

}

/*

** try to find last instruction before 'lastpc' that modified register 'reg'

*/

static int findsetreg (Proto *p, int lastpc, int reg) {

  int pc;

  int setreg = -1;  /* keep last instruction that changed 'reg' */

  for (pc = 0; pc < lastpc; pc++) {

    Instruction i = p->code[pc];

    OpCode op = GET_OPCODE(i);

    int a = GETARG_A(i);

    switch (op) {

      case OP_LOADNIL: {

        int b = GETARG_B(i);

        if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */

          setreg = pc;

        break;

      }

      case OP_TFORCALL: {

        if (reg >= a + 2) setreg = pc;  /* affect all regs above its base */

        break;

      }

      case OP_CALL:

      case OP_TAILCALL: {

        if (reg >= a) setreg = pc;  /* affect all registers above base */

        break;

      }

      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)

          pc += b;  /* do the jump */

        break;

      }

      case OP_TEST: {

        if (reg == a) setreg = pc;  /* jumped code can change 'a' */

        break;

      }

      default:

        if (testAMode(op) && reg == a)  /* any instruction that set A */

          setreg = pc;

        break;

    }

  }

  return setreg;

}

static const char *getobjname (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:

      case OP_GETTABLE: {

        int k = GETARG_C(i);  /* key index */

        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: {

        *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 */

        kname(p, pc, k, name);

        return "method";

      }

      default: break;  /* go through to return NULL */

    }

  }

  return NULL;  /* could not find reasonable name */

}

static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {

  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

** (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->u.l.base; p < ci->top; p++)

    if (o == p) return 1;

  return 0;

}

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 = 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);

  else

    luaG_runerror(L, "attempt to %s a %s value", op, t);

}

l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {

  if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;

  lua_assert(!ttisstring(p1) && !ttisnumber(p2));

  luaG_typeerror(L, p1, "concatenate");

}

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 */

  luaG_typeerror(L, p2, "perform arithmetic on");

}

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);

}

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(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);

  }

}

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, 0);  /* call it */

  }

  luaD_throw(L, LUA_ERRRUN);

}

l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {

  va_list argp;

  va_start(argp, fmt);

  addinfo(L, luaO_pushvfstring(L, fmt, argp));

  va_end(argp);

  luaG_errormsg(L);

}