/*

** $Id: ldebug.c,v 2.29.1.6 2008/05/08 16:56:26 roberto Exp $

** Debug Interface

** See Copyright Notice in lua.h

*/

#include <stdarg.h>

#include <stddef.h>

#include <string.h>

#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 (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 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);

}

/*

** 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;

  }

  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;

  lua_lock(L);

  for (ci = L->ci; level > 0 && ci > L->base_ci; ci--) {

    level--;

    if (f_isLua(ci))  /* Lua function? */

      level -= ci->tailcalls;  /* skip lost tail calls */

  }

  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;

  }

  else status = 0;  /* no such level */

  lua_unlock(L);

  return status;

}

static Proto *getluaproto (CallInfo *ci) {

  return (isLua(ci) ? ci_func(ci)->l.p : NULL);

}

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 */

  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)";

    else

      return NULL;

  }

}

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);

  lua_lock(L);

  if (name)

      luaA_pushobject(L, ci->base + (n - 1));

  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);

  lua_lock(L);

  if (name)

      setobjs2s(L, ci->base + (n - 1), L->top - 1);

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

  lua_unlock(L);

  return name;

}

static void funcinfo (lua_Debug *ar, Closure *cl) {

  if (cl->c.isC) {

    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;

    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) {

    setnilvalue(L->top);

  }

  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); 

  }

  incr_top(L);

}

static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,

                    Closure *f, CallInfo *ci) {

  int status = 1;

  if (f == NULL) {

    info_tailcall(ar);

    return status;

  }

  for (; *what; what++) {

    switch (*what) {

      case 'S': {

        funcinfo(ar, f);

        break;

      }

      case 'l': {

        ar->currentline = (ci) ? currentline(L, ci) : -1;

        break;

      }

      case 'u': {

        ar->nups = f->c.nupvalues;

        break;

      }

      case 'n': {

        ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : 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 *f = NULL;

  CallInfo *ci = NULL;

  lua_lock(L);

  if (*what == '>') {

    StkId func = L->top - 1;

    luai_apicheck(L, ttisfunction(func));

    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;

    lua_assert(ttisfunction(ci->func));

    f = clvalue(ci->func);

  }

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

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

    if (f == NULL) setnilvalue(L->top);

    else setclvalue(L, L->top, f);

    incr_top(L);

  }

  if (strchr(what, 'L'))

    collectvalidlines(L, f);

  lua_unlock(L);

  return status;

}

/*

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

** Symbolic Execution and code checker

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

*/

#define check(x)		if (!(x)) return 0;

#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;

    }

    default: return 0;  /* invalid instruction after an open call */

  }

}

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 Instruction symbexec (const Proto *pt, 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));

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

    Instruction i = pt->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 */

        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 */

        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 */

        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);

        }

        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 */

        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);

        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);

}

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,

                               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";

      }

      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' */

        break;

      }

      case OP_GETTABLE: {

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

        *name = kname(p, k);

        return "field";

      }

      case OP_GETUPVAL: {

        int u = GETARG_B(i);  /* upvalue index */