external/mit/lua/dist/src/ldebug.c

   1 /*      $NetBSD: ldebug.c,v 1.1.1.2 2012/03/15 00:08:08 alnsn Exp $     */
   2
   3 /*
   4 ** $Id: ldebug.c,v 1.1.1.2 2012/03/15 00:08:08 alnsn Exp $
   5 ** Debug Interface
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9
  10 #include <stdarg.h>
  11 #include <stddef.h>
  12 #include <string.h>
  13
  14
  15 #define ldebug_c
  16 #define LUA_CORE
  17
  18 #include "lua.h"
  19
  20 #include "lapi.h"
  21 #include "lcode.h"
  22 #include "ldebug.h"
  23 #include "ldo.h"
  24 #include "lfunc.h"
  25 #include "lobject.h"
  26 #include "lopcodes.h"
  27 #include "lstate.h"
  28 #include "lstring.h"
  29 #include "ltable.h"
  30 #include "ltm.h"
  31 #include "lvm.h"
  32
  33
  34
  35 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
  36
  37
  38 static int currentpc (lua_State *L, CallInfo *ci) {
  39   if (!isLua(ci)) return -1;  /* function is not a Lua function? */
  40   if (ci == L->ci)
  41     ci->savedpc = L->savedpc;
  42   return pcRel(ci->savedpc, ci_func(ci)->l.p);
  43 }
  44
  45
  46 static int currentline (lua_State *L, CallInfo *ci) {
  47   int pc = currentpc(L, ci);
  48   if (pc < 0)
  49     return -1;  /* only active lua functions have current-line information */
  50   else
  51     return getline(ci_func(ci)->l.p, pc);
  52 }
  53
  54
  55 /*
  56 ** this function can be called asynchronous (e.g. during a signal)
  57 */
  58 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
  59   if (func == NULL || mask == 0) {  /* turn off hooks? */
  60     mask = 0;
  61     func = NULL;
  62   }
  63   L->hook = func;
  64   L->basehookcount = count;
  65   resethookcount(L);
  66   L->hookmask = cast_byte(mask);
  67   return 1;
  68 }
  69
  70
  71 LUA_API lua_Hook lua_gethook (lua_State *L) {
  72   return L->hook;
  73 }
  74
  75
  76 LUA_API int lua_gethookmask (lua_State *L) {
  77   return L->hookmask;
  78 }
  79
  80
  81 LUA_API int lua_gethookcount (lua_State *L) {
  82   return L->basehookcount;
  83 }
  84
  85
  86 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
  87   int status;
  88   CallInfo *ci;
  89   lua_lock(L);
  90   for (ci = L->ci; level > 0 && ci > L->base_ci; ci--) {
  91     level--;
  92     if (f_isLua(ci))  /* Lua function? */
  93       level -= ci->tailcalls;  /* skip lost tail calls */
  94   }
  95   if (level == 0 && ci > L->base_ci) {  /* level found? */
  96     status = 1;
  97     ar->i_ci = cast_int(ci - L->base_ci);
  98   }
  99   else if (level < 0) {  /* level is of a lost tail call? */
 100     status = 1;
 101     ar->i_ci = 0;
 102   }
 103   else status = 0;  /* no such level */
 104   lua_unlock(L);
 105   return status;
 106 }
 107
 108
 109 static Proto *getluaproto (CallInfo *ci) {
 110   return (isLua(ci) ? ci_func(ci)->l.p : NULL);
 111 }
 112
 113
 114 static const char *findlocal (lua_State *L, CallInfo *ci, int n) {
 115   const char *name;
 116   Proto *fp = getluaproto(ci);
 117   if (fp && (name = luaF_getlocalname(fp, n, currentpc(L, ci))) != NULL)
 118     return name;  /* is a local variable in a Lua function */
 119   else {
 120     StkId limit = (ci == L->ci) ? L->top : (ci+1)->func;
 121     if (limit - ci->base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
 122       return "(*temporary)";
 123     else
 124       return NULL;
 125   }
 126 }
 127
 128
 129 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
 130   CallInfo *ci = L->base_ci + ar->i_ci;
 131   const char *name = findlocal(L, ci, n);
 132   lua_lock(L);
 133   if (name)
 134       luaA_pushobject(L, ci->base + (n - 1));
 135   lua_unlock(L);
 136   return name;
 137 }
 138
 139
 140 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
 141   CallInfo *ci = L->base_ci + ar->i_ci;
 142   const char *name = findlocal(L, ci, n);
 143   lua_lock(L);
 144   if (name)
 145       setobjs2s(L, ci->base + (n - 1), L->top - 1);
 146   L->top--;  /* pop value */
 147   lua_unlock(L);
 148   return name;
 149 }
 150
 151
 152 static void funcinfo (lua_Debug *ar, Closure *cl) {
 153   if (cl->c.isC) {
 154     ar->source = "=[C]";
 155     ar->linedefined = -1;
 156     ar->lastlinedefined = -1;
 157     ar->what = "C";
 158   }
 159   else {
 160     ar->source = getstr(cl->l.p->source);
 161     ar->linedefined = cl->l.p->linedefined;
 162     ar->lastlinedefined = cl->l.p->lastlinedefined;
 163     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
 164   }
 165   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 166 }
 167
 168
 169 static void info_tailcall (lua_Debug *ar) {
 170   ar->name = ar->namewhat = "";
 171   ar->what = "tail";
 172   ar->lastlinedefined = ar->linedefined = ar->currentline = -1;
 173   ar->source = "=(tail call)";
 174   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
 175   ar->nups = 0;
 176 }
 177
 178
 179 static void collectvalidlines (lua_State *L, Closure *f) {
 180   if (f == NULL || f->c.isC) {
 181     setnilvalue(L->top);
 182   }
 183   else {
 184     Table *t = luaH_new(L, 0, 0);
 185     int *lineinfo = f->l.p->lineinfo;
 186     int i;
 187     for (i=0; i<f->l.p->sizelineinfo; i++)
 188       setbvalue(luaH_setnum(L, t, lineinfo[i]), 1);
 189     sethvalue(L, L->top, t);
 190   }
 191   incr_top(L);
 192 }
 193
 194
 195 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
 196                     Closure *f, CallInfo *ci) {
 197   int status = 1;
 198   if (f == NULL) {
 199     info_tailcall(ar);
 200     return status;
 201   }
 202   for (; *what; what++) {
 203     switch (*what) {
 204       case 'S': {
 205         funcinfo(ar, f);
 206         break;
 207       }
 208       case 'l': {
 209         ar->currentline = (ci) ? currentline(L, ci) : -1;
 210         break;
 211       }
 212       case 'u': {
 213         ar->nups = f->c.nupvalues;
 214         break;
 215       }
 216       case 'n': {
 217         ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : NULL;
 218         if (ar->namewhat == NULL) {
 219           ar->namewhat = "";  /* not found */
 220           ar->name = NULL;
 221         }
 222         break;
 223       }
 224       case 'L':
 225       case 'f':  /* handled by lua_getinfo */
 226         break;
 227       default: status = 0;  /* invalid option */
 228     }
 229   }
 230   return status;
 231 }
 232
 233
 234 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
 235   int status;
 236   Closure *f = NULL;
 237   CallInfo *ci = NULL;
 238   lua_lock(L);
 239   if (*what == '>') {
 240     StkId func = L->top - 1;
 241     luai_apicheck(L, ttisfunction(func));
 242     what++;  /* skip the '>' */
 243     f = clvalue(func);
 244     L->top--;  /* pop function */
 245   }
 246   else if (ar->i_ci != 0) {  /* no tail call? */
 247     ci = L->base_ci + ar->i_ci;
 248     lua_assert(ttisfunction(ci->func));
 249     f = clvalue(ci->func);
 250   }
 251   status = auxgetinfo(L, what, ar, f, ci);
 252   if (strchr(what, 'f')) {
 253     if (f == NULL) setnilvalue(L->top);
 254     else setclvalue(L, L->top, f);
 255     incr_top(L);
 256   }
 257   if (strchr(what, 'L'))
 258     collectvalidlines(L, f);
 259   lua_unlock(L);
 260   return status;
 261 }
 262
 263
 264 /*
 265 ** {======================================================
 266 ** Symbolic Execution and code checker
 267 ** =======================================================
 268 */
 269
 270 #define check(x)                if (!(x)) return 0;
 271
 272 #define checkjump(pt,pc)        check(0 <= pc && pc < pt->sizecode)
 273
 274 #define checkreg(pt,reg)        check((reg) < (pt)->maxstacksize)
 275
 276
 277
 278 static int precheck (const Proto *pt) {
 279   check(pt->maxstacksize <= MAXSTACK);
 280   check(pt->numparams+(pt->is_vararg & VARARG_HASARG) <= pt->maxstacksize);
 281   check(!(pt->is_vararg & VARARG_NEEDSARG) ||
 282               (pt->is_vararg & VARARG_HASARG));
 283   check(pt->sizeupvalues <= pt->nups);
 284   check(pt->sizelineinfo == pt->sizecode || pt->sizelineinfo == 0);
 285   check(pt->sizecode > 0 && GET_OPCODE(pt->code[pt->sizecode-1]) == OP_RETURN);
 286   return 1;
 287 }
 288
 289
 290 #define checkopenop(pt,pc)      luaG_checkopenop((pt)->code[(pc)+1])
 291
 292 int luaG_checkopenop (Instruction i) {
 293   switch (GET_OPCODE(i)) {
 294     case OP_CALL:
 295     case OP_TAILCALL:
 296     case OP_RETURN:
 297     case OP_SETLIST: {
 298       check(GETARG_B(i) == 0);
 299       return 1;
 300     }
 301     default: return 0;  /* invalid instruction after an open call */
 302   }
 303 }
 304
 305
 306 static int checkArgMode (const Proto *pt, int r, enum OpArgMask mode) {
 307   switch (mode) {
 308     case OpArgN: check(r == 0); break;
 309     case OpArgU: break;
 310     case OpArgR: checkreg(pt, r); break;
 311     case OpArgK:
 312       check(ISK(r) ? INDEXK(r) < pt->sizek : r < pt->maxstacksize);
 313       break;
 314   }
 315   return 1;
 316 }
 317
 318
 319 static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
 320   int pc;
 321   int last;  /* stores position of last instruction that changed `reg' */
 322   last = pt->sizecode-1;  /* points to final return (a `neutral' instruction) */
 323   check(precheck(pt));
 324   for (pc = 0; pc < lastpc; pc++) {
 325     Instruction i = pt->code[pc];
 326     OpCode op = GET_OPCODE(i);
 327     int a = GETARG_A(i);
 328     int b = 0;
 329     int c = 0;
 330     check(op < NUM_OPCODES);
 331     checkreg(pt, a);
 332     switch (getOpMode(op)) {
 333       case iABC: {
 334         b = GETARG_B(i);
 335         c = GETARG_C(i);
 336         check(checkArgMode(pt, b, getBMode(op)));
 337         check(checkArgMode(pt, c, getCMode(op)));
 338         break;
 339       }
 340       case iABx: {
 341         b = GETARG_Bx(i);
 342         if (getBMode(op) == OpArgK) check(b < pt->sizek);
 343         break;
 344       }
 345       case iAsBx: {
 346         b = GETARG_sBx(i);
 347         if (getBMode(op) == OpArgR) {
 348           int dest = pc+1+b;
 349           check(0 <= dest && dest < pt->sizecode);
 350           if (dest > 0) {
 351             int j;
 352             /* check that it does not jump to a setlist count; this
 353                is tricky, because the count from a previous setlist may
 354                have the same value of an invalid setlist; so, we must
 355                go all the way back to the first of them (if any) */
 356             for (j = 0; j < dest; j++) {
 357               Instruction d = pt->code[dest-1-j];
 358               if (!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0)) break;
 359             }
 360             /* if 'j' is even, previous value is not a setlist (even if
 361                it looks like one) */
 362             check((j&1) == 0);
 363           }
 364         }
 365         break;
 366       }
 367     }
 368     if (testAMode(op)) {
 369       if (a == reg) last = pc;  /* change register `a' */
 370     }
 371     if (testTMode(op)) {
 372       check(pc+2 < pt->sizecode);  /* check skip */
 373       check(GET_OPCODE(pt->code[pc+1]) == OP_JMP);
 374     }
 375     switch (op) {
 376       case OP_LOADBOOL: {
 377         if (c == 1) {  /* does it jump? */
 378           check(pc+2 < pt->sizecode);  /* check its jump */
 379           check(GET_OPCODE(pt->code[pc+1]) != OP_SETLIST ||
 380                 GETARG_C(pt->code[pc+1]) != 0);
 381         }
 382         break;
 383       }
 384       case OP_LOADNIL: {
 385         if (a <= reg && reg <= b)
 386           last = pc;  /* set registers from `a' to `b' */
 387         break;
 388       }
 389       case OP_GETUPVAL:
 390       case OP_SETUPVAL: {
 391         check(b < pt->nups);
 392         break;
 393       }
 394       case OP_GETGLOBAL:
 395       case OP_SETGLOBAL: {
 396         check(ttisstring(&pt->k[b]));
 397         break;
 398       }
 399       case OP_SELF: {
 400         checkreg(pt, a+1);
 401         if (reg == a+1) last = pc;
 402         break;
 403       }
 404       case OP_CONCAT: {
 405         check(b < c);  /* at least two operands */
 406         break;
 407       }
 408       case OP_TFORLOOP: {
 409         check(c >= 1);  /* at least one result (control variable) */
 410         checkreg(pt, a+2+c);  /* space for results */
 411         if (reg >= a+2) last = pc;  /* affect all regs above its base */
 412         break;
 413       }
 414       case OP_FORLOOP:
 415       case OP_FORPREP:
 416         checkreg(pt, a+3);
 417         /* go through */
 418       case OP_JMP: {
 419         int dest = pc+1+b;
 420         /* not full check and jump is forward and do not skip `lastpc'? */
 421         if (reg != NO_REG && pc < dest && dest <= lastpc)
 422           pc += b;  /* do the jump */
 423         break;
 424       }
 425       case OP_CALL:
 426       case OP_TAILCALL: {
 427         if (b != 0) {
 428           checkreg(pt, a+b-1);
 429         }
 430         c--;  /* c = num. returns */
 431         if (c == LUA_MULTRET) {
 432           check(checkopenop(pt, pc));
 433         }
 434         else if (c != 0)
 435           checkreg(pt, a+c-1);
 436         if (reg >= a) last = pc;  /* affect all registers above base */
 437         break;
 438       }
 439       case OP_RETURN: {
 440         b--;  /* b = num. returns */
 441         if (b > 0) checkreg(pt, a+b-1);
 442         break;
 443       }
 444       case OP_SETLIST: {
 445         if (b > 0) checkreg(pt, a + b);
 446         if (c == 0) {
 447           pc++;
 448           check(pc < pt->sizecode - 1);
 449         }
 450         break;
 451       }
 452       case OP_CLOSURE: {
 453         int nup, j;
 454         check(b < pt->sizep);
 455         nup = pt->p[b]->nups;
 456         check(pc + nup < pt->sizecode);
 457         for (j = 1; j <= nup; j++) {
 458           OpCode op1 = GET_OPCODE(pt->code[pc + j]);
 459           check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
 460         }
 461         if (reg != NO_REG)  /* tracing? */
 462           pc += nup;  /* do not 'execute' these pseudo-instructions */
 463         break;
 464       }
 465       case OP_VARARG: {
 466         check((pt->is_vararg & VARARG_ISVARARG) &&
 467              !(pt->is_vararg & VARARG_NEEDSARG));
 468         b--;
 469         if (b == LUA_MULTRET) check(checkopenop(pt, pc));
 470         checkreg(pt, a+b-1);
 471         break;
 472       }
 473       default: break;
 474     }
 475   }
 476   return pt->code[last];
 477 }
 478
 479 #undef check
 480 #undef checkjump
 481 #undef checkreg
 482
 483 /* }====================================================== */
 484
 485
 486 int luaG_checkcode (const Proto *pt) {
 487   return (symbexec(pt, pt->sizecode, NO_REG) != 0);
 488 }
 489
 490
 491 static const char *kname (Proto *p, int c) {
 492   if (ISK(c) && ttisstring(&p->k[INDEXK(c)]))
 493     return svalue(&p->k[INDEXK(c)]);
 494   else
 495     return "?";
 496 }
 497
 498
 499 static const char *getobjname (lua_State *L, CallInfo *ci, int stackpos,
 500                                const char **name) {
 501   if (isLua(ci)) {  /* a Lua function? */
 502     Proto *p = ci_func(ci)->l.p;
 503     int pc = currentpc(L, ci);
 504     Instruction i;
 505     *name = luaF_getlocalname(p, stackpos+1, pc);
 506     if (*name)  /* is a local? */
 507       return "local";
 508     i = symbexec(p, pc, stackpos);  /* try symbolic execution */
 509     lua_assert(pc != -1);
 510     switch (GET_OPCODE(i)) {
 511       case OP_GETGLOBAL: {
 512         int g = GETARG_Bx(i);  /* global index */
 513         lua_assert(ttisstring(&p->k[g]));
 514         *name = svalue(&p->k[g]);
 515         return "global";
 516       }
 517       case OP_MOVE: {
 518         int a = GETARG_A(i);
 519         int b = GETARG_B(i);  /* move from `b' to `a' */
 520         if (b < a)
 521           return getobjname(L, ci, b, name);  /* get name for `b' */
 522         break;
 523       }
 524       case OP_GETTABLE: {
 525         int k = GETARG_C(i);  /* key index */
 526         *name = kname(p, k);
 527         return "field";
 528       }
 529       case OP_GETUPVAL: {
 530         int u = GETARG_B(i);  /* upvalue index */
 531         *name = p->upvalues ? getstr(p->upvalues[u]) : "?";
 532         return "upvalue";
 533       }
 534       case OP_SELF: {
 535         int k = GETARG_C(i);  /* key index */
 536         *name = kname(p, k);
 537         return "method";
 538       }
 539       default: break;
 540     }
 541   }
 542   return NULL;  /* no useful name found */
 543 }
 544
 545
 546 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
 547   Instruction i;
 548   if ((isLua(ci) && ci->tailcalls > 0) || !isLua(ci - 1))
 549     return NULL;  /* calling function is not Lua (or is unknown) */
 550   ci--;  /* calling function */
 551   i = ci_func(ci)->l.p->code[currentpc(L, ci)];
 552   if (GET_OPCODE(i) == OP_CALL || GET_OPCODE(i) == OP_TAILCALL ||
 553       GET_OPCODE(i) == OP_TFORLOOP)
 554     return getobjname(L, ci, GETARG_A(i), name);
 555   else
 556     return NULL;  /* no useful name can be found */
 557 }
 558
 559
 560 /* only ANSI way to check whether a pointer points to an array */
 561 static int isinstack (CallInfo *ci, const TValue *o) {
 562   StkId p;
 563   for (p = ci->base; p < ci->top; p++)
 564     if (o == p) return 1;
 565   return 0;
 566 }
 567
 568
 569 void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
 570   const char *name = NULL;
 571   const char *t = luaT_typenames[ttype(o)];
 572   const char *kind = (isinstack(L->ci, o)) ?
 573                          getobjname(L, L->ci, cast_int(o - L->base), &name) :
 574                          NULL;
 575   if (kind)
 576     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
 577                 op, kind, name, t);
 578   else
 579     luaG_runerror(L, "attempt to %s a %s value", op, t);
 580 }
 581
 582
 583 void luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
 584   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
 585   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
 586   luaG_typeerror(L, p1, "concatenate");
 587 }
 588
 589
 590 void luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
 591   TValue temp;
 592   if (luaV_tonumber(p1, &temp) == NULL)
 593     p2 = p1;  /* first operand is wrong */
 594   luaG_typeerror(L, p2, "perform arithmetic on");
 595 }
 596
 597
 598 int luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
 599   const char *t1 = luaT_typenames[ttype(p1)];
 600   const char *t2 = luaT_typenames[ttype(p2)];
 601   if (t1[2] == t2[2])
 602     luaG_runerror(L, "attempt to compare two %s values", t1);
 603   else
 604     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
 605   return 0;
 606 }
 607
 608
 609 static void addinfo (lua_State *L, const char *msg) {
 610   CallInfo *ci = L->ci;
 611   if (isLua(ci)) {  /* is Lua code? */
 612     char buff[LUA_IDSIZE];  /* add file:line information */
 613     int line = currentline(L, ci);
 614     luaO_chunkid(buff, getstr(getluaproto(ci)->source), LUA_IDSIZE);
 615     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
 616   }
 617 }
 618
 619
 620 void luaG_errormsg (lua_State *L) {
 621   if (L->errfunc != 0) {  /* is there an error handling function? */
 622     StkId errfunc = restorestack(L, L->errfunc);
 623     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
 624     setobjs2s(L, L->top, L->top - 1);  /* move argument */
 625     setobjs2s(L, L->top - 1, errfunc);  /* push function */
 626     incr_top(L);
 627     luaD_call(L, L->top - 2, 1);  /* call it */
 628   }
 629   luaD_throw(L, LUA_ERRRUN);
 630 }
 631
 632
 633 void luaG_runerror (lua_State *L, const char *fmt, ...) {
 634   va_list argp;
 635   va_start(argp, fmt);
 636   addinfo(L, luaO_pushvfstring(L, fmt, argp));
 637   va_end(argp);
 638   luaG_errormsg(L);
 639 }
 640