module/lua/ldebug.c

   1 /* BEGIN CSTYLED */
   2 /*
   3 ** $Id: ldebug.c,v 2.90.1.4 2015/02/19 17:05:13 roberto Exp $
   4 ** Debug Interface
   5 ** See Copyright Notice in lua.h
   6 */
   7
   8
   9 #define ldebug_c
  10 #define LUA_CORE
  11
  12 #include <sys/lua/lua.h>
  13
  14 #include "lapi.h"
  15 #include "lcode.h"
  16 #include "ldebug.h"
  17 #include "ldo.h"
  18 #include "lfunc.h"
  19 #include "lobject.h"
  20 #include "lopcodes.h"
  21 #include "lstate.h"
  22 #include "lstring.h"
  23 #include "ltable.h"
  24 #include "ltm.h"
  25 #include "lvm.h"
  26
  27
  28
  29 #define noLuaClosure(f)         ((f) == NULL || (f)->c.tt == LUA_TCCL)
  30
  31
  32 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
  33
  34
  35 static int currentpc (CallInfo *ci) {
  36   lua_assert(isLua(ci));
  37   return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
  38 }
  39
  40
  41 static int currentline (CallInfo *ci) {
  42   return getfuncline(ci_func(ci)->p, currentpc(ci));
  43 }
  44
  45
  46 static void swapextra (lua_State *L) {
  47   if (L->status == LUA_YIELD) {
  48     CallInfo *ci = L->ci;  /* get function that yielded */
  49     StkId temp = ci->func;  /* exchange its 'func' and 'extra' values */
  50     ci->func = restorestack(L, ci->extra);
  51     ci->extra = savestack(L, temp);
  52   }
  53 }
  54
  55
  56 /*
  57 ** this function can be called asynchronous (e.g. during a signal)
  58 */
  59 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
  60   if (func == NULL || mask == 0) {  /* turn off hooks? */
  61     mask = 0;
  62     func = NULL;
  63   }
  64   if (isLua(L->ci))
  65     L->oldpc = L->ci->u.l.savedpc;
  66   L->hook = func;
  67   L->basehookcount = count;
  68   resethookcount(L);
  69   L->hookmask = cast_byte(mask);
  70   return 1;
  71 }
  72
  73
  74 LUA_API lua_Hook lua_gethook (lua_State *L) {
  75   return L->hook;
  76 }
  77
  78
  79 LUA_API int lua_gethookmask (lua_State *L) {
  80   return L->hookmask;
  81 }
  82
  83
  84 LUA_API int lua_gethookcount (lua_State *L) {
  85   return L->basehookcount;
  86 }
  87
  88
  89 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
  90   int status;
  91   CallInfo *ci;
  92   if (level < 0) return 0;  /* invalid (negative) level */
  93   lua_lock(L);
  94   for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
  95     level--;
  96   if (level == 0 && ci != &L->base_ci) {  /* level found? */
  97     status = 1;
  98     ar->i_ci = ci;
  99   }
 100   else status = 0;  /* no such level */
 101   lua_unlock(L);
 102   return status;
 103 }
 104
 105
 106 static const char *upvalname (Proto *p, int uv) {
 107   TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
 108   if (s == NULL) return "?";
 109   else return getstr(s);
 110 }
 111
 112
 113 static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
 114   int nparams = clLvalue(ci->func)->p->numparams;
 115   if (n >= ci->u.l.base - ci->func - nparams)
 116     return NULL;  /* no such vararg */
 117   else {
 118     *pos = ci->func + nparams + n;
 119     return "(*vararg)";  /* generic name for any vararg */
 120   }
 121 }
 122
 123
 124 static const char *findlocal (lua_State *L, CallInfo *ci, int n,
 125                               StkId *pos) {
 126   const char *name = NULL;
 127   StkId base;
 128   if (isLua(ci)) {
 129     if (n < 0)  /* access to vararg values? */
 130       return findvararg(ci, -n, pos);
 131     else {
 132       base = ci->u.l.base;
 133       name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
 134     }
 135   }
 136   else
 137     base = ci->func + 1;
 138   if (name == NULL) {  /* no 'standard' name? */
 139     StkId limit = (ci == L->ci) ? L->top : ci->next->func;
 140     if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
 141       name = "(*temporary)";  /* generic name for any valid slot */
 142     else
 143       return NULL;  /* no name */
 144   }
 145   *pos = base + (n - 1);
 146   return name;
 147 }
 148
 149
 150 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
 151   const char *name;
 152   lua_lock(L);
 153   swapextra(L);
 154   if (ar == NULL) {  /* information about non-active function? */
 155     if (!isLfunction(L->top - 1))  /* not a Lua function? */
 156       name = NULL;
 157     else  /* consider live variables at function start (parameters) */
 158       name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
 159   }
 160   else {  /* active function; get information through 'ar' */
 161     StkId pos = 0;  /* to avoid warnings */
 162     name = findlocal(L, ar->i_ci, n, &pos);
 163     if (name) {
 164       setobj2s(L, L->top, pos);
 165       api_incr_top(L);
 166     }
 167   }
 168   swapextra(L);
 169   lua_unlock(L);
 170   return name;
 171 }
 172
 173
 174 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 175   StkId pos = 0;  /* to avoid warnings */
 176   const char *name;
 177   lua_lock(L);
 178   swapextra(L);
 179   name = findlocal(L, ar->i_ci, n, &pos);
 180   if (name)
 181     setobjs2s(L, pos, L->top - 1);
 182   L->top--;  /* pop value */
 183   swapextra(L);
 184   lua_unlock(L);
 185   return name;
 186 }
 187
 188
 189 static void funcinfo (lua_Debug *ar, Closure *cl) {
 190   if (noLuaClosure(cl)) {
 191     ar->source = "=[C]";
 192     ar->linedefined = -1;
 193     ar->lastlinedefined = -1;
 194     ar->what = "C";
 195   }
 196   else {
 197     Proto *p = cl->l.p;
 198     ar->source = p->source ? getstr(p->source) : "=?";
 199     ar->linedefined = p->linedefined;
 200     ar->lastlinedefined = p->lastlinedefined;
 201     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
 202   }
 203   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 204 }
 205
 206
 207 static void collectvalidlines (lua_State *L, Closure *f) {
 208   if (noLuaClosure(f)) {
 209     setnilvalue(L->top);
 210     api_incr_top(L);
 211   }
 212   else {
 213     int i;
 214     TValue v;
 215     int *lineinfo = f->l.p->lineinfo;
 216     Table *t = luaH_new(L);  /* new table to store active lines */
 217     sethvalue(L, L->top, t);  /* push it on stack */
 218     api_incr_top(L);
 219     setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
 220     for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
 221       luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
 222   }
 223 }
 224
 225
 226 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
 227                        Closure *f, CallInfo *ci) {
 228   int status = 1;
 229   for (; *what; what++) {
 230     switch (*what) {
 231       case 'S': {
 232         funcinfo(ar, f);
 233         break;
 234       }
 235       case 'l': {
 236         ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
 237         break;
 238       }
 239       case 'u': {
 240         ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
 241         if (noLuaClosure(f)) {
 242           ar->isvararg = 1;
 243           ar->nparams = 0;
 244         }
 245         else {
 246           ar->isvararg = f->l.p->is_vararg;
 247           ar->nparams = f->l.p->numparams;
 248         }
 249         break;
 250       }
 251       case 't': {
 252         ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
 253         break;
 254       }
 255       case 'n': {
 256         /* calling function is a known Lua function? */
 257         if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
 258           ar->namewhat = getfuncname(L, ci->previous, &ar->name);
 259         else
 260           ar->namewhat = NULL;
 261         if (ar->namewhat == NULL) {
 262           ar->namewhat = "";  /* not found */
 263           ar->name = NULL;
 264         }
 265         break;
 266       }
 267       case 'L':
 268       case 'f':  /* handled by lua_getinfo */
 269         break;
 270       default: status = 0;  /* invalid option */
 271     }
 272   }
 273   return status;
 274 }
 275
 276
 277 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
 278   int status;
 279   Closure *cl;
 280   CallInfo *ci;
 281   StkId func;
 282   lua_lock(L);
 283   swapextra(L);
 284   if (*what == '>') {
 285     ci = NULL;
 286     func = L->top - 1;
 287     api_check(L, ttisfunction(func), "function expected");
 288     what++;  /* skip the '>' */
 289     L->top--;  /* pop function */
 290   }
 291   else {
 292     ci = ar->i_ci;
 293     func = ci->func;
 294     lua_assert(ttisfunction(ci->func));
 295   }
 296   cl = ttisclosure(func) ? clvalue(func) : NULL;
 297   status = auxgetinfo(L, what, ar, cl, ci);
 298   if (strchr(what, 'f')) {
 299     setobjs2s(L, L->top, func);
 300     api_incr_top(L);
 301   }
 302   swapextra(L);
 303   if (strchr(what, 'L'))
 304     collectvalidlines(L, cl);
 305   lua_unlock(L);
 306   return status;
 307 }
 308
 309
 310 /*
 311 ** {======================================================
 312 ** Symbolic Execution
 313 ** =======================================================
 314 */
 315
 316 static const char *getobjname (Proto *p, int lastpc, int reg,
 317                                const char **name);
 318
 319
 320 /*
 321 ** find a "name" for the RK value 'c'
 322 */
 323 static void kname (Proto *p, int pc, int c, const char **name) {
 324   if (ISK(c)) {  /* is 'c' a constant? */
 325     TValue *kvalue = &p->k[INDEXK(c)];
 326     if (ttisstring(kvalue)) {  /* literal constant? */
 327       *name = svalue(kvalue);  /* it is its own name */
 328       return;
 329     }
 330     /* else no reasonable name found */
 331   }
 332   else {  /* 'c' is a register */
 333     const char *what = getobjname(p, pc, c, name); /* search for 'c' */
 334     if (what && *what == 'c') {  /* found a constant name? */
 335       return;  /* 'name' already filled */
 336     }
 337     /* else no reasonable name found */
 338   }
 339   *name = "?";  /* no reasonable name found */
 340 }
 341
 342
 343 static int filterpc (int pc, int jmptarget) {
 344   if (pc < jmptarget)  /* is code conditional (inside a jump)? */
 345     return -1;  /* cannot know who sets that register */
 346   else return pc;  /* current position sets that register */
 347 }
 348
 349
 350 /*
 351 ** try to find last instruction before 'lastpc' that modified register 'reg'
 352 */
 353 static int findsetreg (Proto *p, int lastpc, int reg) {
 354   int pc;
 355   int setreg = -1;  /* keep last instruction that changed 'reg' */
 356   int jmptarget = 0;  /* any code before this address is conditional */
 357   for (pc = 0; pc < lastpc; pc++) {
 358     Instruction i = p->code[pc];
 359     OpCode op = GET_OPCODE(i);
 360     int a = GETARG_A(i);
 361     switch (op) {
 362       case OP_LOADNIL: {
 363         int b = GETARG_B(i);
 364         if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
 365           setreg = filterpc(pc, jmptarget);
 366         break;
 367       }
 368       case OP_TFORCALL: {
 369         if (reg >= a + 2)  /* affect all regs above its base */
 370           setreg = filterpc(pc, jmptarget);
 371         break;
 372       }
 373       case OP_CALL:
 374       case OP_TAILCALL: {
 375         if (reg >= a)  /* affect all registers above base */
 376           setreg = filterpc(pc, jmptarget);
 377         break;
 378       }
 379       case OP_JMP: {
 380         int b = GETARG_sBx(i);
 381         int dest = pc + 1 + b;
 382         /* jump is forward and do not skip `lastpc'? */
 383         if (pc < dest && dest <= lastpc) {
 384           if (dest > jmptarget)
 385             jmptarget = dest;  /* update 'jmptarget' */
 386         }
 387         break;
 388       }
 389       case OP_TEST: {
 390         if (reg == a)  /* jumped code can change 'a' */
 391           setreg = filterpc(pc, jmptarget);
 392         break;
 393       }
 394       default:
 395         if (testAMode(op) && reg == a)  /* any instruction that set A */
 396           setreg = filterpc(pc, jmptarget);
 397         break;
 398     }
 399   }
 400   return setreg;
 401 }
 402
 403
 404 static const char *getobjname (Proto *p, int lastpc, int reg,
 405                                const char **name) {
 406   int pc;
 407   *name = luaF_getlocalname(p, reg + 1, lastpc);
 408   if (*name)  /* is a local? */
 409     return "local";
 410   /* else try symbolic execution */
 411   pc = findsetreg(p, lastpc, reg);
 412   if (pc != -1) {  /* could find instruction? */
 413     Instruction i = p->code[pc];
 414     OpCode op = GET_OPCODE(i);
 415     switch (op) {
 416       case OP_MOVE: {
 417         int b = GETARG_B(i);  /* move from 'b' to 'a' */
 418         if (b < GETARG_A(i))
 419           return getobjname(p, pc, b, name);  /* get name for 'b' */
 420         break;
 421       }
 422       case OP_GETTABUP:
 423       case OP_GETTABLE: {
 424         int k = GETARG_C(i);  /* key index */
 425         int t = GETARG_B(i);  /* table index */
 426         const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
 427                          ? luaF_getlocalname(p, t + 1, pc)
 428                          : upvalname(p, t);
 429         kname(p, pc, k, name);
 430         return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
 431       }
 432       case OP_GETUPVAL: {
 433         *name = upvalname(p, GETARG_B(i));
 434         return "upvalue";
 435       }
 436       case OP_LOADK:
 437       case OP_LOADKX: {
 438         int b = (op == OP_LOADK) ? GETARG_Bx(i)
 439                                  : GETARG_Ax(p->code[pc + 1]);
 440         if (ttisstring(&p->k[b])) {
 441           *name = svalue(&p->k[b]);
 442           return "constant";
 443         }
 444         break;
 445       }
 446       case OP_SELF: {
 447         int k = GETARG_C(i);  /* key index */
 448         kname(p, pc, k, name);
 449         return "method";
 450       }
 451       default: break;  /* go through to return NULL */
 452     }
 453   }
 454   return NULL;  /* could not find reasonable name */
 455 }
 456
 457
 458 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
 459   TMS tm;
 460   Proto *p = ci_func(ci)->p;  /* calling function */
 461   int pc = currentpc(ci);  /* calling instruction index */
 462   Instruction i = p->code[pc];  /* calling instruction */
 463   switch (GET_OPCODE(i)) {
 464     case OP_CALL:
 465     case OP_TAILCALL:  /* get function name */
 466       return getobjname(p, pc, GETARG_A(i), name);
 467     case OP_TFORCALL: {  /* for iterator */
 468       *name = "for iterator";
 469        return "for iterator";
 470     }
 471     /* all other instructions can call only through metamethods */
 472     case OP_SELF:
 473     case OP_GETTABUP:
 474     case OP_GETTABLE: tm = TM_INDEX; break;
 475     case OP_SETTABUP:
 476     case OP_SETTABLE: tm = TM_NEWINDEX; break;
 477     case OP_EQ: tm = TM_EQ; break;
 478     case OP_ADD: tm = TM_ADD; break;
 479     case OP_SUB: tm = TM_SUB; break;
 480     case OP_MUL: tm = TM_MUL; break;
 481     case OP_DIV: tm = TM_DIV; break;
 482     case OP_MOD: tm = TM_MOD; break;
 483     case OP_POW: tm = TM_POW; break;
 484     case OP_UNM: tm = TM_UNM; break;
 485     case OP_LEN: tm = TM_LEN; break;
 486     case OP_LT: tm = TM_LT; break;
 487     case OP_LE: tm = TM_LE; break;
 488     case OP_CONCAT: tm = TM_CONCAT; break;
 489     default:
 490       return NULL;  /* else no useful name can be found */
 491   }
 492   *name = getstr(G(L)->tmname[tm]);
 493   return "metamethod";
 494 }
 495
 496 /* }====================================================== */
 497
 498
 499
 500 /*
 501 ** only ANSI way to check whether a pointer points to an array
 502 ** (used only for error messages, so efficiency is not a big concern)
 503 */
 504 static int isinstack (CallInfo *ci, const TValue *o) {
 505   StkId p;
 506   for (p = ci->u.l.base; p < ci->top; p++)
 507     if (o == p) return 1;
 508   return 0;
 509 }
 510
 511
 512 static const char *getupvalname (CallInfo *ci, const TValue *o,
 513                                  const char **name) {
 514   LClosure *c = ci_func(ci);
 515   int i;
 516   for (i = 0; i < c->nupvalues; i++) {
 517     if (c->upvals[i]->v == o) {
 518       *name = upvalname(c->p, i);
 519       return "upvalue";
 520     }
 521   }
 522   return NULL;
 523 }
 524
 525
 526 l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
 527   CallInfo *ci = L->ci;
 528   const char *name = NULL;
 529   const char *t = objtypename(o);
 530   const char *kind = NULL;
 531   if (isLua(ci)) {
 532     kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
 533     if (!kind && isinstack(ci, o))  /* no? try a register */
 534       kind = getobjname(ci_func(ci)->p, currentpc(ci),
 535                         cast_int(o - ci->u.l.base), &name);
 536   }
 537   if (kind)
 538     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
 539                 op, kind, name, t);
 540   else
 541     luaG_runerror(L, "attempt to %s a %s value", op, t);
 542 }
 543
 544
 545 l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
 546   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
 547   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
 548   luaG_typeerror(L, p1, "concatenate");
 549 }
 550
 551
 552 l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
 553   TValue temp;
 554   if (luaV_tonumber(p1, &temp) == NULL)
 555     p2 = p1;  /* first operand is wrong */
 556   luaG_typeerror(L, p2, "perform arithmetic on");
 557 }
 558
 559
 560 l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
 561   const char *t1 = objtypename(p1);
 562   const char *t2 = objtypename(p2);
 563   if (t1 == t2)
 564     luaG_runerror(L, "attempt to compare two %s values", t1);
 565   else
 566     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
 567 }
 568
 569
 570 static void addinfo (lua_State *L, const char *msg) {
 571   CallInfo *ci = L->ci;
 572   if (isLua(ci)) {  /* is Lua code? */
 573     char buff[LUA_IDSIZE];  /* add file:line information */
 574     int line = currentline(ci);
 575     TString *src = ci_func(ci)->p->source;
 576     if (src)
 577       luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
 578     else {  /* no source available; use "?" instead */
 579       buff[0] = '?'; buff[1] = '\0';
 580     }
 581     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
 582   }
 583 }
 584
 585
 586 l_noret luaG_errormsg (lua_State *L) {
 587   if (L->errfunc != 0) {  /* is there an error handling function? */
 588     StkId errfunc = restorestack(L, L->errfunc);
 589     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
 590     setobjs2s(L, L->top, L->top - 1);  /* move argument */
 591     setobjs2s(L, L->top - 1, errfunc);  /* push function */
 592     L->top++;
 593     luaD_call(L, L->top - 2, 1, 0);  /* call it */
 594   }
 595   luaD_throw(L, LUA_ERRRUN);
 596 }
 597
 598
 599 l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
 600   L->runerror++;
 601   va_list argp;
 602   va_start(argp, fmt);
 603   addinfo(L, luaO_pushvfstring(L, fmt, argp));
 604   va_end(argp);
 605   luaG_errormsg(L);
 606   L->runerror--;
 607 }
 608 /* END CSTYLED */