source/libs/lua52/lua52-src/src/ldebug.c

   1 /*
   2 ** $Id: ldebug.c,v 2.90.1.4 2015/02/19 17:05:13 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 static void swapextra (lua_State *L) {
  51   if (L->status == LUA_YIELD) {
  52     CallInfo *ci = L->ci;  /* get function that yielded */
  53     StkId temp = ci->func;  /* exchange its 'func' and 'extra' values */
  54     ci->func = restorestack(L, ci->extra);
  55     ci->extra = savestack(L, temp);
  56   }
  57 }
  58
  59
  60 /*
  61 ** this function can be called asynchronous (e.g. during a signal)
  62 */
  63 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
  64   if (func == NULL || mask == 0) {  /* turn off hooks? */
  65     mask = 0;
  66     func = NULL;
  67   }
  68   if (isLua(L->ci))
  69     L->oldpc = L->ci->u.l.savedpc;
  70   L->hook = func;
  71   L->basehookcount = count;
  72   resethookcount(L);
  73   L->hookmask = cast_byte(mask);
  74   return 1;
  75 }
  76
  77
  78 LUA_API lua_Hook lua_gethook (lua_State *L) {
  79   return L->hook;
  80 }
  81
  82
  83 LUA_API int lua_gethookmask (lua_State *L) {
  84   return L->hookmask;
  85 }
  86
  87
  88 LUA_API int lua_gethookcount (lua_State *L) {
  89   return L->basehookcount;
  90 }
  91
  92
  93 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
  94   int status;
  95   CallInfo *ci;
  96   if (level < 0) return 0;  /* invalid (negative) level */
  97   lua_lock(L);
  98   for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
  99     level--;
 100   if (level == 0 && ci != &L->base_ci) {  /* level found? */
 101     status = 1;
 102     ar->i_ci = ci;
 103   }
 104   else status = 0;  /* no such level */
 105   lua_unlock(L);
 106   return status;
 107 }
 108
 109
 110 static const char *upvalname (Proto *p, int uv) {
 111   TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
 112   if (s == NULL) return "?";
 113   else return getstr(s);
 114 }
 115
 116
 117 static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
 118   int nparams = clLvalue(ci->func)->p->numparams;
 119   if (n >= ci->u.l.base - ci->func - nparams)
 120     return NULL;  /* no such vararg */
 121   else {
 122     *pos = ci->func + nparams + n;
 123     return "(*vararg)";  /* generic name for any vararg */
 124   }
 125 }
 126
 127
 128 static const char *findlocal (lua_State *L, CallInfo *ci, int n,
 129                               StkId *pos) {
 130   const char *name = NULL;
 131   StkId base;
 132   if (isLua(ci)) {
 133     if (n < 0)  /* access to vararg values? */
 134       return findvararg(ci, -n, pos);
 135     else {
 136       base = ci->u.l.base;
 137       name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
 138     }
 139   }
 140   else
 141     base = ci->func + 1;
 142   if (name == NULL) {  /* no 'standard' name? */
 143     StkId limit = (ci == L->ci) ? L->top : ci->next->func;
 144     if (limit - base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
 145       name = "(*temporary)";  /* generic name for any valid slot */
 146     else
 147       return NULL;  /* no name */
 148   }
 149   *pos = base + (n - 1);
 150   return name;
 151 }
 152
 153
 154 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
 155   const char *name;
 156   lua_lock(L);
 157   swapextra(L);
 158   if (ar == NULL) {  /* information about non-active function? */
 159     if (!isLfunction(L->top - 1))  /* not a Lua function? */
 160       name = NULL;
 161     else  /* consider live variables at function start (parameters) */
 162       name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
 163   }
 164   else {  /* active function; get information through 'ar' */
 165     StkId pos = 0;  /* to avoid warnings */
 166     name = findlocal(L, ar->i_ci, n, &pos);
 167     if (name) {
 168       setobj2s(L, L->top, pos);
 169       api_incr_top(L);
 170     }
 171   }
 172   swapextra(L);
 173   lua_unlock(L);
 174   return name;
 175 }
 176
 177
 178 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 179   StkId pos = 0;  /* to avoid warnings */
 180   const char *name;
 181   lua_lock(L);
 182   swapextra(L);
 183   name = findlocal(L, ar->i_ci, n, &pos);
 184   if (name)
 185     setobjs2s(L, pos, L->top - 1);
 186   L->top--;  /* pop value */
 187   swapextra(L);
 188   lua_unlock(L);
 189   return name;
 190 }
 191
 192
 193 static void funcinfo (lua_Debug *ar, Closure *cl) {
 194   if (noLuaClosure(cl)) {
 195     ar->source = "=[C]";
 196     ar->linedefined = -1;
 197     ar->lastlinedefined = -1;
 198     ar->what = "C";
 199   }
 200   else {
 201     Proto *p = cl->l.p;
 202     ar->source = p->source ? getstr(p->source) : "=?";
 203     ar->linedefined = p->linedefined;
 204     ar->lastlinedefined = p->lastlinedefined;
 205     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
 206   }
 207   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 208 }
 209
 210
 211 static void collectvalidlines (lua_State *L, Closure *f) {
 212   if (noLuaClosure(f)) {
 213     setnilvalue(L->top);
 214     api_incr_top(L);
 215   }
 216   else {
 217     int i;
 218     TValue v;
 219     int *lineinfo = f->l.p->lineinfo;
 220     Table *t = luaH_new(L);  /* new table to store active lines */
 221     sethvalue(L, L->top, t);  /* push it on stack */
 222     api_incr_top(L);
 223     setbvalue(&v, 1);  /* boolean 'true' to be the value of all indices */
 224     for (i = 0; i < f->l.p->sizelineinfo; i++)  /* for all lines with code */
 225       luaH_setint(L, t, lineinfo[i], &v);  /* table[line] = true */
 226   }
 227 }
 228
 229
 230 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
 231                        Closure *f, CallInfo *ci) {
 232   int status = 1;
 233   for (; *what; what++) {
 234     switch (*what) {
 235       case 'S': {
 236         funcinfo(ar, f);
 237         break;
 238       }
 239       case 'l': {
 240         ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
 241         break;
 242       }
 243       case 'u': {
 244         ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
 245         if (noLuaClosure(f)) {
 246           ar->isvararg = 1;
 247           ar->nparams = 0;
 248         }
 249         else {
 250           ar->isvararg = f->l.p->is_vararg;
 251           ar->nparams = f->l.p->numparams;
 252         }
 253         break;
 254       }
 255       case 't': {
 256         ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
 257         break;
 258       }
 259       case 'n': {
 260         /* calling function is a known Lua function? */
 261         if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
 262           ar->namewhat = getfuncname(L, ci->previous, &ar->name);
 263         else
 264           ar->namewhat = NULL;
 265         if (ar->namewhat == NULL) {
 266           ar->namewhat = "";  /* not found */
 267           ar->name = NULL;
 268         }
 269         break;
 270       }
 271       case 'L':
 272       case 'f':  /* handled by lua_getinfo */
 273         break;
 274       default: status = 0;  /* invalid option */
 275     }
 276   }
 277   return status;
 278 }
 279
 280
 281 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
 282   int status;
 283   Closure *cl;
 284   CallInfo *ci;
 285   StkId func;
 286   lua_lock(L);
 287   swapextra(L);
 288   if (*what == '>') {
 289     ci = NULL;
 290     func = L->top - 1;
 291     api_check(L, ttisfunction(func), "function expected");
 292     what++;  /* skip the '>' */
 293     L->top--;  /* pop function */
 294   }
 295   else {
 296     ci = ar->i_ci;
 297     func = ci->func;
 298     lua_assert(ttisfunction(ci->func));
 299   }
 300   cl = ttisclosure(func) ? clvalue(func) : NULL;
 301   status = auxgetinfo(L, what, ar, cl, ci);
 302   if (strchr(what, 'f')) {
 303     setobjs2s(L, L->top, func);
 304     api_incr_top(L);
 305   }
 306   swapextra(L);
 307   if (strchr(what, 'L'))
 308     collectvalidlines(L, cl);
 309   lua_unlock(L);
 310   return status;
 311 }
 312
 313
 314 /*
 315 ** {======================================================
 316 ** Symbolic Execution
 317 ** =======================================================
 318 */
 319
 320 static const char *getobjname (Proto *p, int lastpc, int reg,
 321                                const char **name);
 322
 323
 324 /*
 325 ** find a "name" for the RK value 'c'
 326 */
 327 static void kname (Proto *p, int pc, int c, const char **name) {
 328   if (ISK(c)) {  /* is 'c' a constant? */
 329     TValue *kvalue = &p->k[INDEXK(c)];
 330     if (ttisstring(kvalue)) {  /* literal constant? */
 331       *name = svalue(kvalue);  /* it is its own name */
 332       return;
 333     }
 334     /* else no reasonable name found */
 335   }
 336   else {  /* 'c' is a register */
 337     const char *what = getobjname(p, pc, c, name); /* search for 'c' */
 338     if (what && *what == 'c') {  /* found a constant name? */
 339       return;  /* 'name' already filled */
 340     }
 341     /* else no reasonable name found */
 342   }
 343   *name = "?";  /* no reasonable name found */
 344 }
 345
 346
 347 static int filterpc (int pc, int jmptarget) {
 348   if (pc < jmptarget)  /* is code conditional (inside a jump)? */
 349     return -1;  /* cannot know who sets that register */
 350   else return pc;  /* current position sets that register */
 351 }
 352
 353
 354 /*
 355 ** try to find last instruction before 'lastpc' that modified register 'reg'
 356 */
 357 static int findsetreg (Proto *p, int lastpc, int reg) {
 358   int pc;
 359   int setreg = -1;  /* keep last instruction that changed 'reg' */
 360   int jmptarget = 0;  /* any code before this address is conditional */
 361   for (pc = 0; pc < lastpc; pc++) {
 362     Instruction i = p->code[pc];
 363     OpCode op = GET_OPCODE(i);
 364     int a = GETARG_A(i);
 365     switch (op) {
 366       case OP_LOADNIL: {
 367         int b = GETARG_B(i);
 368         if (a <= reg && reg <= a + b)  /* set registers from 'a' to 'a+b' */
 369           setreg = filterpc(pc, jmptarget);
 370         break;
 371       }
 372       case OP_TFORCALL: {
 373         if (reg >= a + 2)  /* affect all regs above its base */
 374           setreg = filterpc(pc, jmptarget);
 375         break;
 376       }
 377       case OP_CALL:
 378       case OP_TAILCALL: {
 379         if (reg >= a)  /* affect all registers above base */
 380           setreg = filterpc(pc, jmptarget);
 381         break;
 382       }
 383       case OP_JMP: {
 384         int b = GETARG_sBx(i);
 385         int dest = pc + 1 + b;
 386         /* jump is forward and do not skip `lastpc'? */
 387         if (pc < dest && dest <= lastpc) {
 388           if (dest > jmptarget)
 389             jmptarget = dest;  /* update 'jmptarget' */
 390         }
 391         break;
 392       }
 393       case OP_TEST: {
 394         if (reg == a)  /* jumped code can change 'a' */
 395           setreg = filterpc(pc, jmptarget);
 396         break;
 397       }
 398       default:
 399         if (testAMode(op) && reg == a)  /* any instruction that set A */
 400           setreg = filterpc(pc, jmptarget);
 401         break;
 402     }
 403   }
 404   return setreg;
 405 }
 406
 407
 408 static const char *getobjname (Proto *p, int lastpc, int reg,
 409                                const char **name) {
 410   int pc;
 411   *name = luaF_getlocalname(p, reg + 1, lastpc);
 412   if (*name)  /* is a local? */
 413     return "local";
 414   /* else try symbolic execution */
 415   pc = findsetreg(p, lastpc, reg);
 416   if (pc != -1) {  /* could find instruction? */
 417     Instruction i = p->code[pc];
 418     OpCode op = GET_OPCODE(i);
 419     switch (op) {
 420       case OP_MOVE: {
 421         int b = GETARG_B(i);  /* move from 'b' to 'a' */
 422         if (b < GETARG_A(i))
 423           return getobjname(p, pc, b, name);  /* get name for 'b' */
 424         break;
 425       }
 426       case OP_GETTABUP:
 427       case OP_GETTABLE: {
 428         int k = GETARG_C(i);  /* key index */
 429         int t = GETARG_B(i);  /* table index */
 430         const char *vn = (op == OP_GETTABLE)  /* name of indexed variable */
 431                          ? luaF_getlocalname(p, t + 1, pc)
 432                          : upvalname(p, t);
 433         kname(p, pc, k, name);
 434         return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
 435       }
 436       case OP_GETUPVAL: {
 437         *name = upvalname(p, GETARG_B(i));
 438         return "upvalue";
 439       }
 440       case OP_LOADK:
 441       case OP_LOADKX: {
 442         int b = (op == OP_LOADK) ? GETARG_Bx(i)
 443                                  : GETARG_Ax(p->code[pc + 1]);
 444         if (ttisstring(&p->k[b])) {
 445           *name = svalue(&p->k[b]);
 446           return "constant";
 447         }
 448         break;
 449       }
 450       case OP_SELF: {
 451         int k = GETARG_C(i);  /* key index */
 452         kname(p, pc, k, name);
 453         return "method";
 454       }
 455       default: break;  /* go through to return NULL */
 456     }
 457   }
 458   return NULL;  /* could not find reasonable name */
 459 }
 460
 461
 462 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
 463   TMS tm;
 464   Proto *p = ci_func(ci)->p;  /* calling function */
 465   int pc = currentpc(ci);  /* calling instruction index */
 466   Instruction i = p->code[pc];  /* calling instruction */
 467   switch (GET_OPCODE(i)) {
 468     case OP_CALL:
 469     case OP_TAILCALL:  /* get function name */
 470       return getobjname(p, pc, GETARG_A(i), name);
 471     case OP_TFORCALL: {  /* for iterator */
 472       *name = "for iterator";
 473        return "for iterator";
 474     }
 475     /* all other instructions can call only through metamethods */
 476     case OP_SELF:
 477     case OP_GETTABUP:
 478     case OP_GETTABLE: tm = TM_INDEX; break;
 479     case OP_SETTABUP:
 480     case OP_SETTABLE: tm = TM_NEWINDEX; break;
 481     case OP_EQ: tm = TM_EQ; break;
 482     case OP_ADD: tm = TM_ADD; break;
 483     case OP_SUB: tm = TM_SUB; break;
 484     case OP_MUL: tm = TM_MUL; break;
 485     case OP_DIV: tm = TM_DIV; break;
 486     case OP_MOD: tm = TM_MOD; break;
 487     case OP_POW: tm = TM_POW; break;
 488     case OP_UNM: tm = TM_UNM; break;
 489     case OP_LEN: tm = TM_LEN; break;
 490     case OP_LT: tm = TM_LT; break;
 491     case OP_LE: tm = TM_LE; break;
 492     case OP_CONCAT: tm = TM_CONCAT; break;
 493     default:
 494       return NULL;  /* else no useful name can be found */
 495   }
 496   *name = getstr(G(L)->tmname[tm]);
 497   return "metamethod";
 498 }
 499
 500 /* }====================================================== */
 501
 502
 503
 504 /*
 505 ** only ANSI way to check whether a pointer points to an array
 506 ** (used only for error messages, so efficiency is not a big concern)
 507 */
 508 static int isinstack (CallInfo *ci, const TValue *o) {
 509   StkId p;
 510   for (p = ci->u.l.base; p < ci->top; p++)
 511     if (o == p) return 1;
 512   return 0;
 513 }
 514
 515
 516 static const char *getupvalname (CallInfo *ci, const TValue *o,
 517                                  const char **name) {
 518   LClosure *c = ci_func(ci);
 519   int i;
 520   for (i = 0; i < c->nupvalues; i++) {
 521     if (c->upvals[i]->v == o) {
 522       *name = upvalname(c->p, i);
 523       return "upvalue";
 524     }
 525   }
 526   return NULL;
 527 }
 528
 529
 530 l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
 531   CallInfo *ci = L->ci;
 532   const char *name = NULL;
 533   const char *t = objtypename(o);
 534   const char *kind = NULL;
 535   if (isLua(ci)) {
 536     kind = getupvalname(ci, o, &name);  /* check whether 'o' is an upvalue */
 537     if (!kind && isinstack(ci, o))  /* no? try a register */
 538       kind = getobjname(ci_func(ci)->p, currentpc(ci),
 539                         cast_int(o - ci->u.l.base), &name);
 540   }
 541   if (kind)
 542     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
 543                 op, kind, name, t);
 544   else
 545     luaG_runerror(L, "attempt to %s a %s value", op, t);
 546 }
 547
 548
 549 l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
 550   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
 551   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
 552   luaG_typeerror(L, p1, "concatenate");
 553 }
 554
 555
 556 l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
 557   TValue temp;
 558   if (luaV_tonumber(p1, &temp) == NULL)
 559     p2 = p1;  /* first operand is wrong */
 560   luaG_typeerror(L, p2, "perform arithmetic on");
 561 }
 562
 563
 564 l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
 565   const char *t1 = objtypename(p1);
 566   const char *t2 = objtypename(p2);
 567   if (t1 == t2)
 568     luaG_runerror(L, "attempt to compare two %s values", t1);
 569   else
 570     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
 571 }
 572
 573
 574 static void addinfo (lua_State *L, const char *msg) {
 575   CallInfo *ci = L->ci;
 576   if (isLua(ci)) {  /* is Lua code? */
 577     char buff[LUA_IDSIZE];  /* add file:line information */
 578     int line = currentline(ci);
 579     TString *src = ci_func(ci)->p->source;
 580     if (src)
 581       luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
 582     else {  /* no source available; use "?" instead */
 583       buff[0] = '?'; buff[1] = '\0';
 584     }
 585     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
 586   }
 587 }
 588
 589
 590 l_noret luaG_errormsg (lua_State *L) {
 591   if (L->errfunc != 0) {  /* is there an error handling function? */
 592     StkId errfunc = restorestack(L, L->errfunc);
 593     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
 594     setobjs2s(L, L->top, L->top - 1);  /* move argument */
 595     setobjs2s(L, L->top - 1, errfunc);  /* push function */
 596     L->top++;
 597     luaD_call(L, L->top - 2, 1, 0);  /* call it */
 598   }
 599   luaD_throw(L, LUA_ERRRUN);
 600 }
 601
 602
 603 l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
 604   va_list argp;
 605   va_start(argp, fmt);
 606   addinfo(L, luaO_pushvfstring(L, fmt, argp));
 607   va_end(argp);
 608   luaG_errormsg(L);
 609 }
 610