liblua/ldebug.c

   1 /*
   2 ** $Id: ldebug.c,v 2.90 2012/08/16 17:34:28 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 #define noLuaClosure(f)         ((f) == NULL || (f)->c.tt == LUA_TCCL)
  34
  35
  36 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
  37
  38
  39 static int currentpc (CallInfo *ci) {
  40   lua_assert(isLua(ci));
  41   return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
  42 }
  43
  44
  45 static int currentline (CallInfo *ci) {
  46   return getfuncline(ci_func(ci)->p, currentpc(ci));
  47 }
  48
  49
  50 /*
  51 ** this function can be called asynchronous (e.g. during a signal)
  52 */
  53 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
  54   if (func == NULL || mask == 0) {  /* turn off hooks? */
  55     mask = 0;
  56     func = NULL;
  57   }
  58   if (isLua(L->ci))
  59     L->oldpc = L->ci->u.l.savedpc;
  60   L->hook = func;
  61   L->basehookcount = count;
  62   resethookcount(L);
  63   L->hookmask = cast_byte(mask);
  64   return 1;
  65 }
  66
  67
  68 LUA_API lua_Hook lua_gethook (lua_State *L) {
  69   return L->hook;
  70 }
  71
  72
  73 LUA_API int lua_gethookmask (lua_State *L) {
  74   return L->hookmask;
  75 }
  76
  77
  78 LUA_API int lua_gethookcount (lua_State *L) {
  79   return L->basehookcount;
  80 }
  81
  82
  83 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
  84   int status;
  85   CallInfo *ci;
  86   if (level < 0) return 0;  /* invalid (negative) level */
  87   lua_lock(L);
  88   for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
  89     level--;
  90   if (level == 0 && ci != &L->base_ci) {  /* level found? */
  91     status = 1;
  92     ar->i_ci = ci;
  93   }
  94   else status = 0;  /* no such level */
  95   lua_unlock(L);
  96   return status;
  97 }
  98
  99
 100 static const char *upvalname (Proto *p, int uv) {
 101   TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
 102   if (s == NULL) return "?";
 103   else return getstr(s);
 104 }
 105
 106
 107 static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
 108   int nparams = clLvalue(ci->func)->p->numparams;
 109   if (n >= ci->u.l.base - ci->func - nparams)
 110     return NULL;  /* no such vararg */
 111   else {
 112     *pos = ci->func + nparams + n;
 113     return "(*vararg)";  /* generic name for any vararg */
 114   }
 115 }
 116
 117
 118 static const char *findlocal (lua_State *L, CallInfo *ci, int n,
 119                               StkId *pos) {
 120   const char *name = NULL;
 121   StkId base;
 122   if (isLua(ci)) {
 123     if (n < 0)  /* access to vararg values? */
 124       return findvararg(ci, -n, pos);
 125     else {
 126       base = ci->u.l.base;
 127       name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
 128     }
 129   }
 130   else
 131     base = ci->func + 1;
 132   if (name == NULL) {  /* no 'standard' name? */
 133     StkId limit = (ci == L->ci) ? L->top : ci->next->func;
 134     if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
 135       name = "(*temporary)";  /* generic name for any valid slot */
 136     else
 137       return NULL;  /* no name */
 138   }
 139   *pos = base + (n - 1);
 140   return name;
 141 }
 142
 143
 144 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
 145   const char *name;
 146   lua_lock(L);
 147   if (ar == NULL) {  /* information about non-active function? */
 148     if (!isLfunction(L->top - 1))  /* not a Lua function? */
 149       name = NULL;
 150     else  /* consider live variables at function start (parameters) */
 151       name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
 152   }
 153   else {  /* active function; get information through 'ar' */
 154     StkId pos = 0;  /* to avoid warnings */
 155     name = findlocal(L, ar->i_ci, n, &pos);
 156     if (name) {
 157       setobj2s(L, L->top, pos);
 158       api_incr_top(L);
 159     }
 160   }
 161   lua_unlock(L);
 162   return name;
 163 }
 164
 165
 166 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 167   StkId pos = 0;  /* to avoid warnings */
 168   const char *name = findlocal(L, ar->i_ci, n, &pos);
 169   lua_lock(L);
 170   if (name)
 171     setobjs2s(L, pos, L->top - 1);
 172   L->top--;  /* pop value */
 173   lua_unlock(L);
 174   return name;
 175 }
 176
 177
 178 static void funcinfo (lua_Debug *ar, Closure *cl) {
 179   if (noLuaClosure(cl)) {
 180     ar->source = "=[C]";
 181     ar->linedefined = -1;
 182     ar->lastlinedefined = -1;
 183     ar->what = "C";
 184   }
 185   else {
 186     Proto *p = cl->l.p;
 187     ar->source = p->source ? getstr(p->source) : "=?";
 188     ar->linedefined = p->linedefined;
 189     ar->lastlinedefined = p->lastlinedefined;
 190     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
 191   }
 192   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 193 }
 194
 195
 196 static void collectvalidlines (lua_State *L, Closure *f) {
 197   if (noLuaClosure(f)) {
 198     setnilvalue(L->top);
 199     api_incr_top(L);
 200   }
 201   else {
 202     int i;
 203     TValue v;
 204     int *lineinfo = f->l.p->lineinfo;
 205     Table *t = luaH_new(L);  /* new table to store active lines */
 206     sethvalue(L, L->top, t);  /* push it on stack */
 207     api_incr_top(L);
 208     setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
 209     for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
 210       luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
 211   }
 212 }
 213
 214
 215 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
 216                        Closure *f, CallInfo *ci) {
 217   int status = 1;
 218   for (; *what; what++) {
 219     switch (*what) {
 220       case 'S': {
 221         funcinfo(ar, f);
 222         break;
 223       }
 224       case 'l': {
 225         ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
 226         break;
 227       }
 228       case 'u': {
 229         ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
 230         if (noLuaClosure(f)) {
 231           ar->isvararg = 1;
 232           ar->nparams = 0;
 233         }
 234         else {
 235           ar->isvararg = f->l.p->is_vararg;
 236           ar->nparams = f->l.p->numparams;
 237         }
 238         break;
 239       }
 240       case 't': {
 241         ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
 242         break;
 243       }
 244       case 'n': {
 245         /* calling function is a known Lua function? */
 246         if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
 247           ar->namewhat = getfuncname(L, ci->previous, &ar->name);
 248         else
 249           ar->namewhat = NULL;
 250         if (ar->namewhat == NULL) {
 251           ar->namewhat = "";  /* not found */
 252           ar->name = NULL;
 253         }
 254         break;
 255       }
 256       case 'L':
 257       case 'f':  /* handled by lua_getinfo */
 258         break;
 259       default: status = 0;  /* invalid option */
 260     }
 261   }
 262   return status;
 263 }
 264
 265
 266 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
 267   int status;
 268   Closure *cl;
 269   CallInfo *ci;
 270   StkId func;
 271   lua_lock(L);
 272   if (*what == '>') {
 273     ci = NULL;
 274     func = L->top - 1;
 275     api_check(L, ttisfunction(func), "function expected");
 276     what++;  /* skip the '>' */
 277     L->top--;  /* pop function */
 278   }
 279   else {
 280     ci = ar->i_ci;
 281     func = ci->func;
 282     lua_assert(ttisfunction(ci->func));
 283   }
 284   cl = ttisclosure(func) ? clvalue(func) : NULL;
 285   status = auxgetinfo(L, what, ar, cl, ci);
 286   if (strchr(what, 'f')) {
 287     setobjs2s(L, L->top, func);
 288     api_incr_top(L);
 289   }
 290   if (strchr(what, 'L'))
 291     collectvalidlines(L, cl);
 292   lua_unlock(L);
 293   return status;
 294 }
 295
 296
 297 /*
 298 ** {======================================================
 299 ** Symbolic Execution
 300 ** =======================================================
 301 */
 302
 303 static const char *getobjname (Proto *p, int lastpc, int reg,
 304                                const char **name);
 305
 306
 307 /*
 308 ** find a "name" for the RK value 'c'
 309 */
 310 static void kname (Proto *p, int pc, int c, const char **name) {
 311   if (ISK(c)) {  /* is 'c' a constant? */
 312     TValue *kvalue = &p->k[INDEXK(c)];
 313     if (ttisstring(kvalue)) {  /* literal constant? */
 314       *name = svalue(kvalue);  /* it is its own name */
 315       return;
 316     }
 317     /* else no reasonable name found */
 318   }
 319   else {  /* 'c' is a register */
 320     const char *what = getobjname(p, pc, c, name); /* search for 'c' */
 321     if (what && *what == 'c') {  /* found a constant name? */
 322       return;  /* 'name' already filled */
 323     }
 324     /* else no reasonable name found */
 325   }
 326   *name = "?";  /* no reasonable name found */
 327 }
 328
 329
 330 /*
 331 ** try to find last instruction before 'lastpc' that modified register 'reg'
 332 */
 333 static int findsetreg (Proto *p, int lastpc, int reg) {
 334   int pc;
 335   int setreg = -1;  /* keep last instruction that changed 'reg' */
 336   for (pc = 0; pc < lastpc; pc++) {
 337     Instruction i = p->code[pc];
 338     OpCode op = GET_OPCODE(i);
 339     int a = GETARG_A(i);
 340     switch (op) {
 341       case OP_LOADNIL: {
 342         int b = GETARG_B(i);
 343         if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
 344           setreg = pc;
 345         break;
 346       }
 347       case OP_TFORCALL: {
 348         if (reg >= a + 2) setreg = pc;  /* affect all regs above its base */
 349         break;
 350       }
 351       case OP_CALL:
 352       case OP_TAILCALL: {
 353         if (reg >= a) setreg = pc;  /* affect all registers above base */
 354         break;
 355       }
 356       case OP_JMP: {
 357         int b = GETARG_sBx(i);
 358         int dest = pc + 1 + b;
 359         /* jump is forward and do not skip `lastpc'? */
 360         if (pc < dest && dest <= lastpc)
 361           pc += b;  /* do the jump */
 362         break;
 363       }
 364       case OP_TEST: {
 365         if (reg == a) setreg = pc;  /* jumped code can change 'a' */
 366         break;
 367       }
 368       default:
 369         if (testAMode(op) && reg == a)  /* any instruction that set A */
 370           setreg = pc;
 371         break;
 372     }
 373   }
 374   return setreg;
 375 }
 376
 377
 378 static const char *getobjname (Proto *p, int lastpc, int reg,
 379                                const char **name) {
 380   int pc;
 381   *name = luaF_getlocalname(p, reg + 1, lastpc);
 382   if (*name)  /* is a local? */
 383     return "local";
 384   /* else try symbolic execution */
 385   pc = findsetreg(p, lastpc, reg);
 386   if (pc != -1) {  /* could find instruction? */
 387     Instruction i = p->code[pc];
 388     OpCode op = GET_OPCODE(i);
 389     switch (op) {
 390       case OP_MOVE: {
 391         int b = GETARG_B(i);  /* move from 'b' to 'a' */
 392         if (b < GETARG_A(i))
 393           return getobjname(p, pc, b, name);  /* get name for 'b' */
 394         break;
 395       }
 396       case OP_GETTABUP:
 397       case OP_GETTABLE: {
 398         int k = GETARG_C(i);  /* key index */
 399         int t = GETARG_B(i);  /* table index */
 400         const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
 401                          ? luaF_getlocalname(p, t + 1, pc)
 402                          : upvalname(p, t);
 403         kname(p, pc, k, name);
 404         return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
 405       }
 406       case OP_GETUPVAL: {
 407         *name = upvalname(p, GETARG_B(i));
 408         return "upvalue";
 409       }
 410       case OP_LOADK:
 411       case OP_LOADKX: {
 412         int b = (op == OP_LOADK) ? GETARG_Bx(i)
 413                                  : GETARG_Ax(p->code[pc + 1]);
 414         if (ttisstring(&p->k[b])) {
 415           *name = svalue(&p->k[b]);
 416           return "constant";
 417         }
 418         break;
 419       }
 420       case OP_SELF: {
 421         int k = GETARG_C(i);  /* key index */
 422         kname(p, pc, k, name);
 423         return "method";
 424       }
 425       default: break;  /* go through to return NULL */
 426     }
 427   }
 428   return NULL;  /* could not find reasonable name */
 429 }
 430
 431
 432 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
 433   TMS tm;
 434   Proto *p = ci_func(ci)->p;  /* calling function */
 435   int pc = currentpc(ci);  /* calling instruction index */
 436   Instruction i = p->code[pc];  /* calling instruction */
 437   switch (GET_OPCODE(i)) {
 438     case OP_CALL:
 439     case OP_TAILCALL:  /* get function name */
 440       return getobjname(p, pc, GETARG_A(i), name);
 441     case OP_TFORCALL: {  /* for iterator */
 442       *name = "for iterator";
 443        return "for iterator";
 444     }
 445     /* all other instructions can call only through metamethods */
 446     case OP_SELF:
 447     case OP_GETTABUP:
 448     case OP_GETTABLE: tm = TM_INDEX; break;
 449     case OP_SETTABUP:
 450     case OP_SETTABLE: tm = TM_NEWINDEX; break;
 451     case OP_EQ: tm = TM_EQ; break;
 452     case OP_ADD: tm = TM_ADD; break;
 453     case OP_SUB: tm = TM_SUB; break;
 454     case OP_MUL: tm = TM_MUL; break;
 455     case OP_DIV: tm = TM_DIV; break;
 456     case OP_MOD: tm = TM_MOD; break;
 457     case OP_POW: tm = TM_POW; break;
 458     case OP_UNM: tm = TM_UNM; break;
 459     case OP_LEN: tm = TM_LEN; break;
 460     case OP_LT: tm = TM_LT; break;
 461     case OP_LE: tm = TM_LE; break;
 462     case OP_CONCAT: tm = TM_CONCAT; break;
 463     default:
 464       return NULL;  /* else no useful name can be found */
 465   }
 466   *name = getstr(G(L)->tmname[tm]);
 467   return "metamethod";
 468 }
 469
 470 /* }====================================================== */
 471
 472
 473
 474 /*
 475 ** only ANSI way to check whether a pointer points to an array
 476 ** (used only for error messages, so efficiency is not a big concern)
 477 */
 478 static int isinstack (CallInfo *ci, const TValue *o) {
 479   StkId p;
 480   for (p = ci->u.l.base; p < ci->top; p++)
 481     if (o == p) return 1;
 482   return 0;
 483 }
 484
 485
 486 static const char *getupvalname (CallInfo *ci, const TValue *o,
 487                                  const char **name) {
 488   LClosure *c = ci_func(ci);
 489   int i;
 490   for (i = 0; i < c->nupvalues; i++) {
 491     if (c->upvals[i]->v == o) {
 492       *name = upvalname(c->p, i);
 493       return "upvalue";
 494     }
 495   }
 496   return NULL;
 497 }
 498
 499
 500 l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
 501   CallInfo *ci = L->ci;
 502   const char *name = NULL;
 503   const char *t = objtypename(o);
 504   const char *kind = NULL;
 505   if (isLua(ci)) {
 506     kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
 507     if (!kind && isinstack(ci, o))  /* no? try a register */
 508       kind = getobjname(ci_func(ci)->p, currentpc(ci),
 509                         cast_int(o - ci->u.l.base), &name);
 510   }
 511   if (kind)
 512     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
 513                 op, kind, name, t);
 514   else
 515     luaG_runerror(L, "attempt to %s a %s value", op, t);
 516 }
 517
 518
 519 l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
 520   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
 521   lua_assert(!ttisstring(p1) && !ttisnumber(p2));
 522   luaG_typeerror(L, p1, "concatenate");
 523 }
 524
 525
 526 l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
 527   TValue temp;
 528   if (luaV_tonumber(p1, &temp) == NULL)
 529     p2 = p1;  /* first operand is wrong */
 530   luaG_typeerror(L, p2, "perform arithmetic on");
 531 }
 532
 533
 534 l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
 535   const char *t1 = objtypename(p1);
 536   const char *t2 = objtypename(p2);
 537   if (t1 == t2)
 538     luaG_runerror(L, "attempt to compare two %s values", t1);
 539   else
 540     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
 541 }
 542
 543
 544 static void addinfo (lua_State *L, const char *msg) {
 545   CallInfo *ci = L->ci;
 546   if (isLua(ci)) {  /* is Lua code? */
 547     char buff[LUA_IDSIZE];  /* add file:line information */
 548     int line = currentline(ci);
 549     TString *src = ci_func(ci)->p->source;
 550     if (src)
 551       luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
 552     else {  /* no source available; use "?" instead */
 553       buff[0] = '?'; buff[1] = '\0';
 554     }
 555     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
 556   }
 557 }
 558
 559
 560 l_noret luaG_errormsg (lua_State *L) {
 561   if (L->errfunc != 0) {  /* is there an error handling function? */
 562     StkId errfunc = restorestack(L, L->errfunc);
 563     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
 564     setobjs2s(L, L->top, L->top - 1);  /* move argument */
 565     setobjs2s(L, L->top - 1, errfunc);  /* push function */
 566     L->top++;
 567     luaD_call(L, L->top - 2, 1, 0);  /* call it */
 568   }
 569   luaD_throw(L, LUA_ERRRUN);
 570 }
 571
 572
 573 l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
 574   va_list argp;
 575   va_start(argp, fmt);
 576   addinfo(L, luaO_pushvfstring(L, fmt, argp));
 577   va_end(argp);
 578   luaG_errormsg(L);
 579 }
 580