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      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 
    581