src/ldebug.c

   1 /*
   2 ** $Id: ldebug.c,v 2.29.1.6 2008/05/08 16:56:26 roberto Exp $
   3 ** Debug Interface
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <stdarg.h>
   9 #include <stddef.h>
  10 #include <string.h>
  11
  12
  13 #define ldebug_c
  14 #define LUA_CORE
  15
  16 #include "lua.h"
  17
  18 #include "lapi.h"
  19 #include "lcode.h"
  20 #include "ldebug.h"
  21 #include "ldo.h"
  22 #include "lfunc.h"
  23 #include "lobject.h"
  24 #include "lopcodes.h"
  25 #include "lstate.h"
  26 #include "lstring.h"
  27 #include "ltable.h"
  28 #include "ltm.h"
  29 #include "lvm.h"
  30
  31
  32
  33 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
  34
  35
  36 static int currentpc (lua_State *L, CallInfo *ci) {
  37   if (!isLua(ci)) return -1;  /* function is not a Lua function? */
  38   if (ci == L->ci)
  39     ci->savedpc = L->savedpc;
  40   return pcRel(ci->savedpc, ci_func(ci)->l.p);
  41 }
  42
  43
  44 static int currentline (lua_State *L, CallInfo *ci) {
  45   int pc = currentpc(L, ci);
  46   if (pc < 0)
  47     return -1;  /* only active lua functions have current-line information */
  48   else
  49     return getline(ci_func(ci)->l.p, pc);
  50 }
  51
  52
  53 /*
  54 ** this function can be called asynchronous (e.g. during a signal)
  55 */
  56 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
  57   if (func == NULL || mask == 0) {  /* turn off hooks? */
  58     mask = 0;
  59     func = NULL;
  60   }
  61   L->hook = func;
  62   L->basehookcount = count;
  63   resethookcount(L);
  64   L->hookmask = cast_byte(mask);
  65   return 1;
  66 }
  67
  68
  69 LUA_API lua_Hook lua_gethook (lua_State *L) {
  70   return L->hook;
  71 }
  72
  73
  74 LUA_API int lua_gethookmask (lua_State *L) {
  75   return L->hookmask;
  76 }
  77
  78
  79 LUA_API int lua_gethookcount (lua_State *L) {
  80   return L->basehookcount;
  81 }
  82
  83
  84 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
  85   int status;
  86   CallInfo *ci;
  87   lua_lock(L);
  88   for (ci = L->ci; level > 0 && ci > L->base_ci; ci--) {
  89     level--;
  90     if (f_isLua(ci))  /* Lua function? */
  91       level -= ci->tailcalls;  /* skip lost tail calls */
  92   }
  93   if (level == 0 && ci > L->base_ci) {  /* level found? */
  94     status = 1;
  95     ar->i_ci = cast_int(ci - L->base_ci);
  96   }
  97   else if (level < 0) {  /* level is of a lost tail call? */
  98     status = 1;
  99     ar->i_ci = 0;
 100   }
 101   else status = 0;  /* no such level */
 102   lua_unlock(L);
 103   return status;
 104 }
 105
 106
 107 static Proto *getluaproto (CallInfo *ci) {
 108   return (isLua(ci) ? ci_func(ci)->l.p : NULL);
 109 }
 110
 111
 112 static const char *findlocal (lua_State *L, CallInfo *ci, int n) {
 113   const char *name;
 114   Proto *fp = getluaproto(ci);
 115   if (fp && (name = luaF_getlocalname(fp, n, currentpc(L, ci))) != NULL)
 116     return name;  /* is a local variable in a Lua function */
 117   else {
 118     StkId limit = (ci == L->ci) ? L->top : (ci+1)->func;
 119     if (limit - ci->base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
 120       return "(*temporary)";
 121     else
 122       return NULL;
 123   }
 124 }
 125
 126
 127 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
 128   CallInfo *ci = L->base_ci + ar->i_ci;
 129   const char *name = findlocal(L, ci, n);
 130   lua_lock(L);
 131   if (name)
 132       luaA_pushobject(L, ci->base + (n - 1));
 133   lua_unlock(L);
 134   return name;
 135 }
 136
 137
 138 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 139   CallInfo *ci = L->base_ci + ar->i_ci;
 140   const char *name = findlocal(L, ci, n);
 141   lua_lock(L);
 142   if (name)
 143       setobjs2s(L, ci->base + (n - 1), L->top - 1);
 144   L->top--;  /* pop value */
 145   lua_unlock(L);
 146   return name;
 147 }
 148
 149
 150 static void funcinfo (lua_Debug *ar, Closure *cl) {
 151   if (cl->c.isC) {
 152     ar->source = "=[C]";
 153     ar->linedefined = -1;
 154     ar->lastlinedefined = -1;
 155     ar->what = "C";
 156   }
 157   else {
 158     ar->source = getstr(cl->l.p->source);
 159     ar->linedefined = cl->l.p->linedefined;
 160     ar->lastlinedefined = cl->l.p->lastlinedefined;
 161     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
 162   }
 163   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 164 }
 165
 166
 167 static void info_tailcall (lua_Debug *ar) {
 168   ar->name = ar->namewhat = "";
 169   ar->what = "tail";
 170   ar->lastlinedefined = ar->linedefined = ar->currentline = -1;
 171   ar->source = "=(tail call)";
 172   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 173   ar->nups = 0;
 174 }
 175
 176
 177 static void collectvalidlines (lua_State *L, Closure *f) {
 178   if (f == NULL || f->c.isC) {
 179     setnilvalue(L->top);
 180   }
 181   else {
 182     Table *t = luaH_new(L, 0, 0);
 183     int *lineinfo = f->l.p->lineinfo;
 184     int i;
 185     for (i=0; i<f->l.p->sizelineinfo; i++)
 186       setbvalue(luaH_setnum(L, t, lineinfo[i]), 1);
 187     sethvalue(L, L->top, t);
 188   }
 189   incr_top(L);
 190 }
 191
 192
 193 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
 194                     Closure *f, CallInfo *ci) {
 195   int status = 1;
 196   if (f == NULL) {
 197     info_tailcall(ar);
 198     return status;
 199   }
 200   for (; *what; what++) {
 201     switch (*what) {
 202       case 'S': {
 203         funcinfo(ar, f);
 204         break;
 205       }
 206       case 'l': {
 207         ar->currentline = (ci) ? currentline(L, ci) : -1;
 208         break;
 209       }
 210       case 'u': {
 211         ar->nups = f->c.nupvalues;
 212         break;
 213       }
 214       case 'n': {
 215         ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : NULL;
 216         if (ar->namewhat == NULL) {
 217           ar->namewhat = "";  /* not found */
 218           ar->name = NULL;
 219         }
 220         break;
 221       }
 222       case 'L':
 223       case 'f':  /* handled by lua_getinfo */
 224         break;
 225       default: status = 0;  /* invalid option */
 226     }
 227   }
 228   return status;
 229 }
 230
 231
 232 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
 233   int status;
 234   Closure *f = NULL;
 235   CallInfo *ci = NULL;
 236   lua_lock(L);
 237   if (*what == '>') {
 238     StkId func = L->top - 1;
 239     luai_apicheck(L, ttisfunction(func));
 240     what++;  /* skip the '>' */
 241     f = clvalue(func);
 242     L->top--;  /* pop function */
 243   }
 244   else if (ar->i_ci != 0) {  /* no tail call? */
 245     ci = L->base_ci + ar->i_ci;
 246     lua_assert(ttisfunction(ci->func));
 247     f = clvalue(ci->func);
 248   }
 249   status = auxgetinfo(L, what, ar, f, ci);
 250   if (strchr(what, 'f')) {
 251     if (f == NULL) setnilvalue(L->top);
 252     else setclvalue(L, L->top, f);
 253     incr_top(L);
 254   }
 255   if (strchr(what, 'L'))
 256     collectvalidlines(L, f);
 257   lua_unlock(L);
 258   return status;
 259 }
 260
 261
 262 /*
 263 ** {======================================================
 264 ** Symbolic Execution and code checker
 265 ** =======================================================
 266 */
 267
 268 #define check(x)                if (!(x)) return 0;
 269
 270 #define checkjump(pt,pc)        check(0 <= pc && pc < pt->sizecode)
 271
 272 #define checkreg(pt,reg)        check((reg) < (pt)->maxstacksize)
 273
 274
 275
 276 static int precheck (const Proto *pt) {
 277   check(pt->maxstacksize <= MAXSTACK);
 278   check(pt->numparams+(pt->is_vararg & VARARG_HASARG) <= pt->maxstacksize);
 279   check(!(pt->is_vararg & VARARG_NEEDSARG) ||
 280               (pt->is_vararg & VARARG_HASARG));
 281   check(pt->sizeupvalues <= pt->nups);
 282   check(pt->sizelineinfo == pt->sizecode || pt->sizelineinfo == 0);
 283   check(pt->sizecode > 0 && GET_OPCODE(pt->code[pt->sizecode-1]) == OP_RETURN);
 284   return 1;
 285 }
 286
 287
 288 #define checkopenop(pt,pc)      luaG_checkopenop((pt)->code[(pc)+1])
 289
 290 int luaG_checkopenop (Instruction i) {
 291   switch (GET_OPCODE(i)) {
 292     case OP_CALL:
 293     case OP_TAILCALL:
 294     case OP_RETURN:
 295     case OP_SETLIST: {
 296       check(GETARG_B(i) == 0);
 297       return 1;
 298     }
 299     default: return 0;  /* invalid instruction after an open call */
 300   }
 301 }
 302
 303
 304 static int checkArgMode (const Proto *pt, int r, enum OpArgMask mode) {
 305   switch (mode) {
 306     case OpArgN: check(r == 0); break;
 307     case OpArgU: break;
 308     case OpArgR: checkreg(pt, r); break;
 309     case OpArgK:
 310       check(ISK(r) ? INDEXK(r) < pt->sizek : r < pt->maxstacksize);
 311       break;
 312   }
 313   return 1;
 314 }
 315
 316
 317 static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
 318   int pc;
 319   int last;  /* stores position of last instruction that changed `reg' */
 320   last = pt->sizecode-1;  /* points to final return (a `neutral' instruction) */
 321   check(precheck(pt));
 322   for (pc = 0; pc < lastpc; pc++) {
 323     Instruction i = pt->code[pc];
 324     OpCode op = GET_OPCODE(i);
 325     int a = GETARG_A(i);
 326     int b = 0;
 327     int c = 0;
 328     check(op < NUM_OPCODES);
 329     checkreg(pt, a);
 330     switch (getOpMode(op)) {
 331       case iABC: {
 332         b = GETARG_B(i);
 333         c = GETARG_C(i);
 334         check(checkArgMode(pt, b, getBMode(op)));
 335         check(checkArgMode(pt, c, getCMode(op)));
 336         break;
 337       }
 338       case iABx: {
 339         b = GETARG_Bx(i);
 340         if (getBMode(op) == OpArgK) check(b < pt->sizek);
 341         break;
 342       }
 343       case iAsBx: {
 344         b = GETARG_sBx(i);
 345         if (getBMode(op) == OpArgR) {
 346           int dest = pc+1+b;
 347           check(0 <= dest && dest < pt->sizecode);
 348           if (dest > 0) {
 349             int j;
 350             /* check that it does not jump to a setlist count; this
 351                is tricky, because the count from a previous setlist may
 352                have the same value of an invalid setlist; so, we must
 353                go all the way back to the first of them (if any) */
 354             for (j = 0; j < dest; j++) {
 355               Instruction d = pt->code[dest-1-j];
 356               if (!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0)) break;
 357             }
 358             /* if 'j' is even, previous value is not a setlist (even if
 359                it looks like one) */
 360             check((j&1) == 0);
 361           }
 362         }
 363         break;
 364       }
 365     }
 366     if (testAMode(op)) {
 367       if (a == reg) last = pc;  /* change register `a' */
 368     }
 369     if (testTMode(op)) {
 370       check(pc+2 < pt->sizecode);  /* check skip */
 371       check(GET_OPCODE(pt->code[pc+1]) == OP_JMP);
 372     }
 373     switch (op) {
 374       case OP_LOADBOOL: {
 375         if (c == 1) {  /* does it jump? */
 376           check(pc+2 < pt->sizecode);  /* check its jump */
 377           check(GET_OPCODE(pt->code[pc+1]) != OP_SETLIST ||
 378                 GETARG_C(pt->code[pc+1]) != 0);
 379         }
 380         break;
 381       }
 382       case OP_LOADNIL: {
 383         if (a <= reg && reg <= b)
 384           last = pc;  /* set registers from `a' to `b' */
 385         break;
 386       }
 387       case OP_GETUPVAL:
 388       case OP_SETUPVAL: {
 389         check(b < pt->nups);
 390         break;
 391       }
 392       case OP_GETGLOBAL:
 393       case OP_SETGLOBAL: {
 394         check(ttisstring(&pt->k[b]));
 395         break;
 396       }
 397       case OP_SELF: {
 398         checkreg(pt, a+1);
 399         if (reg == a+1) last = pc;
 400         break;
 401       }
 402       case OP_CONCAT: {
 403         check(b < c);  /* at least two operands */
 404         break;
 405       }
 406       case OP_TFORLOOP: {
 407         check(c >= 1);  /* at least one result (control variable) */
 408         checkreg(pt, a+2+c);  /* space for results */
 409         if (reg >= a+2) last = pc;  /* affect all regs above its base */
 410         break;
 411       }
 412       case OP_FORLOOP:
 413       case OP_FORPREP:
 414         checkreg(pt, a+3);
 415         /* go through */
 416       case OP_JMP: {
 417         int dest = pc+1+b;
 418         /* not full check and jump is forward and do not skip `lastpc'? */
 419         if (reg != NO_REG && pc < dest && dest <= lastpc)
 420           pc += b;  /* do the jump */
 421         break;
 422       }
 423       case OP_CALL:
 424       case OP_TAILCALL: {
 425         if (b != 0) {
 426           checkreg(pt, a+b-1);
 427         }
 428         c--;  /* c = num. returns */
 429         if (c == LUA_MULTRET) {
 430           check(checkopenop(pt, pc));
 431         }
 432         else if (c != 0)
 433           checkreg(pt, a+c-1);
 434         if (reg >= a) last = pc;  /* affect all registers above base */
 435         break;
 436       }
 437       case OP_RETURN: {
 438         b--;  /* b = num. returns */
 439         if (b > 0) checkreg(pt, a+b-1);
 440         break;
 441       }
 442       case OP_SETLIST: {
 443         if (b > 0) checkreg(pt, a + b);
 444         if (c == 0) {
 445           pc++;
 446           check(pc < pt->sizecode - 1);
 447         }
 448         break;
 449       }
 450       case OP_CLOSURE: {
 451         int nup, j;
 452         check(b < pt->sizep);
 453         nup = pt->p[b]->nups;
 454         check(pc + nup < pt->sizecode);
 455         for (j = 1; j <= nup; j++) {
 456           OpCode op1 = GET_OPCODE(pt->code[pc + j]);
 457           check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
 458         }
 459         if (reg != NO_REG)  /* tracing? */
 460           pc += nup;  /* do not 'execute' these pseudo-instructions */
 461         break;
 462       }
 463       case OP_VARARG: {
 464         check((pt->is_vararg & VARARG_ISVARARG) &&
 465              !(pt->is_vararg & VARARG_NEEDSARG));
 466         b--;
 467         if (b == LUA_MULTRET) check(checkopenop(pt, pc));
 468         checkreg(pt, a+b-1);
 469         break;
 470       }
 471       default: break;
 472     }
 473   }
 474   return pt->code[last];
 475 }
 476
 477 #undef check
 478 #undef checkjump
 479 #undef checkreg
 480
 481 /* }====================================================== */
 482
 483
 484 int luaG_checkcode (const Proto *pt) {
 485   return (symbexec(pt, pt->sizecode, NO_REG) != 0);
 486 }
 487
 488
 489 static const char *kname (Proto *p, int c) {
 490   if (ISK(c) && ttisstring(&p->k[INDEXK(c)]))
 491     return svalue(&p->k[INDEXK(c)]);
 492   else
 493     return "?";
 494 }
 495
 496
 497 static const char *getobjname (lua_State *L, CallInfo *ci, int stackpos,
 498                                const char **name) {
 499   if (isLua(ci)) {  /* a Lua function? */
 500     Proto *p = ci_func(ci)->l.p;
 501     int pc = currentpc(L, ci);
 502     Instruction i;
 503     *name = luaF_getlocalname(p, stackpos+1, pc);
 504     if (*name)  /* is a local? */
 505       return "local";
 506     i = symbexec(p, pc, stackpos);  /* try symbolic execution */
 507     lua_assert(pc != -1);
 508     switch (GET_OPCODE(i)) {
 509       case OP_GETGLOBAL: {
 510         int g = GETARG_Bx(i);  /* global index */
 511         lua_assert(ttisstring(&p->k[g]));
 512         *name = svalue(&p->k[g]);
 513         return "global";
 514       }
 515       case OP_MOVE: {
 516         int a = GETARG_A(i);
 517         int b = GETARG_B(i);  /* move from `b' to `a' */
 518         if (b < a)
 519           return getobjname(L, ci, b, name);  /* get name for `b' */
 520         break;
 521       }
 522       case OP_GETTABLE: {
 523         int k = GETARG_C(i);  /* key index */
 524         *name = kname(p, k);
 525         return "field";
 526       }
 527       case OP_GETUPVAL: {
 528         int u = GETARG_B(i);  /* upvalue index */
 529         *name = p->upvalues ? getstr(p->upvalues[u]) : "?";
 530         return "upvalue";
 531       }
 532       case OP_SELF: {
 533         int k = GETARG_C(i);  /* key index */
 534         *name = kname(p, k);
 535         return "method";
 536       }
 537       default: break;
 538     }
 539   }
 540   return NULL;  /* no useful name found */
 541 }
 542
 543
 544 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
 545   Instruction i;
 546   if ((isLua(ci) && ci->tailcalls > 0) || !isLua(ci - 1))
 547     return NULL;  /* calling function is not Lua (or is unknown) */
 548   ci--;  /* calling function */
 549   i = ci_func(ci)->l.p->code[currentpc(L, ci)];
 550   if (GET_OPCODE(i) == OP_CALL || GET_OPCODE(i) == OP_TAILCALL ||
 551       GET_OPCODE(i) == OP_TFORLOOP)
 552     return getobjname(L, ci, GETARG_A(i), name);
 553   else
 554     return NULL;  /* no useful name can be found */
 555 }
 556
 557
 558 /* only ANSI way to check whether a pointer points to an array */
 559 static int isinstack (CallInfo *ci, const TValue *o) {
 560   StkId p;
 561   for (p = ci->base; p < ci->top; p++)
 562     if (o == p) return 1;
 563   return 0;
 564 }
 565
 566
 567 void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
 568   const char *name = NULL;
 569   const char *t = luaT_typenames[ttype(o)];
 570   const char *kind = (isinstack(L->ci, o)) ?
 571                          getobjname(L, L->ci, cast_int(o - L->base), &name) :
 572                          NULL;
 573   if (kind)
 574     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
 575                 op, kind, name, t);
 576   else
 577     luaG_runerror(L, "attempt to %s a %s value", op, t);
 578 }
 579
 580
 581 void luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
 582   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
 583   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
 584   luaG_typeerror(L, p1, "concatenate");
 585 }
 586
 587
 588 void luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
 589   TValue temp;
 590   if (luaV_tonumber(p1, &temp) == NULL)
 591     p2 = p1;  /* first operand is wrong */
 592   luaG_typeerror(L, p2, "perform arithmetic on");
 593 }
 594
 595
 596 int luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
 597   const char *t1 = luaT_typenames[ttype(p1)];
 598   const char *t2 = luaT_typenames[ttype(p2)];
 599   if (t1[2] == t2[2])
 600     luaG_runerror(L, "attempt to compare two %s values", t1);
 601   else
 602     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
 603   return 0;
 604 }
 605
 606
 607 static void addinfo (lua_State *L, const char *msg) {
 608   CallInfo *ci = L->ci;
 609   if (isLua(ci)) {  /* is Lua code? */
 610     char buff[LUA_IDSIZE];  /* add file:line information */
 611     int line = currentline(L, ci);
 612     luaO_chunkid(buff, getstr(getluaproto(ci)->source), LUA_IDSIZE);
 613     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
 614   }
 615 }
 616
 617
 618 void luaG_errormsg (lua_State *L) {
 619   if (L->errfunc != 0) {  /* is there an error handling function? */
 620     StkId errfunc = restorestack(L, L->errfunc);
 621     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
 622     setobjs2s(L, L->top, L->top - 1);  /* move argument */
 623     setobjs2s(L, L->top - 1, errfunc);  /* push function */
 624     incr_top(L);
 625     luaD_call(L, L->top - 2, 1);  /* call it */
 626   }
 627   luaD_throw(L, LUA_ERRRUN);
 628 }
 629
 630
 631 void luaG_runerror (lua_State *L, const char *fmt, ...) {
 632   va_list argp;
 633   va_start(argp, fmt);
 634   addinfo(L, luaO_pushvfstring(L, fmt, argp));
 635   va_end(argp);
 636   luaG_errormsg(L);
 637 }
 638