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# lua/ldebug.c

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    00001 /*
    00002 ** $Id: ldebug.c,v 1.3 2007/07/15 17:56:10 rse Exp $
    00003 ** Debug Interface
    00004 ** See Copyright Notice in lua.h
    00005 */
    00006
    00007
    00008 #include <stdarg.h>
    00009 #include <stddef.h>
    00010 #include <string.h>
    00011
    00012
    00013 #define ldebug_c
    00014 #define LUA_CORE
    00015
    00016 #include "lua.h"
    00017
    00018 #include "lapi.h"
    00019 #include "lcode.h"
    00020 #include "ldebug.h"
    00021 #include "ldo.h"
    00022 #include "lfunc.h"
    00023 #include "lobject.h"
    00024 #include "lopcodes.h"
    00025 #include "lstate.h"
    00026 #include "lstring.h"
    00027 #include "ltable.h"
    00028 #include "ltm.h"
    00029 #include "lvm.h"
    00030
    00031
    00032
    00033 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
    00034
    00035
    00036 static int currentpc (lua_State *L, CallInfo *ci) {
    00037   if (!isLua(ci)) return -1;  /* function is not a Lua function? */
    00038   if (ci == L->ci)
    00039     ci->savedpc = L->savedpc;
    00040   return pcRel(ci->savedpc, ci_func(ci)->l.p);
    00041 }
    00042
    00043
    00044 static int currentline (lua_State *L, CallInfo *ci) {
    00045   int pc = currentpc(L, ci);
    00046   if (pc < 0)
    00047     return -1;  /* only active lua functions have current-line information */
    00048   else
    00049     return getline(ci_func(ci)->l.p, pc);
    00050 }
    00051
    00052
    00053 /*
    00054 ** this function can be called asynchronous (e.g. during a signal)
    00055 */
    00056 LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
    00057   if (func == NULL || mask == 0) {  /* turn off hooks? */
    00058     mask = 0;
    00059     func = NULL;
    00060   }
    00061   L->hook = func;
    00062   L->basehookcount = count;
    00063   resethookcount(L);
    00064   L->hookmask = cast_byte(mask);
    00065   return 1;
    00066 }
    00067
    00068
    00069 LUA_API lua_Hook lua_gethook (lua_State *L) {
    00070   return L->hook;
    00071 }
    00072
    00073
    00074 LUA_API int lua_gethookmask (lua_State *L) {
    00075   return L->hookmask;
    00076 }
    00077
    00078
    00079 LUA_API int lua_gethookcount (lua_State *L) {
    00080   return L->basehookcount;
    00081 }
    00082
    00083
    00084 LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
    00085   int status;
    00086   CallInfo *ci;
    00087   lua_lock(L);
    00088   for (ci = L->ci; level > 0 && ci > L->base_ci; ci--) {
    00089     level--;
    00090     if (f_isLua(ci))  /* Lua function? */
    00091       level -= ci->tailcalls;  /* skip lost tail calls */
    00092   }
    00093   if (level == 0 && ci > L->base_ci) {  /* level found? */
    00094     status = 1;
    00095     ar->i_ci = cast_int(ci - L->base_ci);
    00096   }
    00097   else if (level < 0) {  /* level is of a lost tail call? */
    00098     status = 1;
    00099     ar->i_ci = 0;
    00100   }
    00101   else status = 0;  /* no such level */
    00102   lua_unlock(L);
    00103   return status;
    00104 }
    00105
    00106
    00107 static Proto *getluaproto (CallInfo *ci) {
    00108   return (isLua(ci) ? ci_func(ci)->l.p : NULL);
    00109 }
    00110
    00111
    00112 static const char *findlocal (lua_State *L, CallInfo *ci, int n) {
    00113   const char *name;
    00114   Proto *fp = getluaproto(ci);
    00115   if (fp && (name = luaF_getlocalname(fp, n, currentpc(L, ci))) != NULL)
    00116     return name;  /* is a local variable in a Lua function */
    00117   else {
    00118     StkId limit = (ci == L->ci) ? L->top : (ci+1)->func;
    00119     if (limit - ci->base >= n && n > 0)  /* is 'n' inside 'ci' stack? */
    00120       return "(*temporary)";
    00121     else
    00122       return NULL;
    00123   }
    00124 }
    00125
    00126
    00127 LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
    00128   CallInfo *ci = L->base_ci + ar->i_ci;
    00129   const char *name = findlocal(L, ci, n);
    00130   lua_lock(L);
    00131   if (name)
    00132       luaA_pushobject(L, ci->base + (n - 1));
    00133   lua_unlock(L);
    00134   return name;
    00135 }
    00136
    00137
    00138 LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
    00139   CallInfo *ci = L->base_ci + ar->i_ci;
    00140   const char *name = findlocal(L, ci, n);
    00141   lua_lock(L);
    00142   if (name)
    00143       setobjs2s(L, ci->base + (n - 1), L->top - 1);
    00144   L->top--;  /* pop value */
    00145   lua_unlock(L);
    00146   return name;
    00147 }
    00148
    00149
    00150 static void funcinfo (lua_Debug *ar, Closure *cl) {
    00151   if (cl->c.isC) {
    00152     ar->source = "=[C]";
    00153     ar->linedefined = -1;
    00154     ar->lastlinedefined = -1;
    00155     ar->what = "C";
    00156   }
    00157   else {
    00158     ar->source = getstr(cl->l.p->source);
    00159     ar->linedefined = cl->l.p->linedefined;
    00160     ar->lastlinedefined = cl->l.p->lastlinedefined;
    00161     ar->what = (ar->linedefined == 0) ? "main" : "Lua";
    00162   }
    00163   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
    00164 }
    00165
    00166
    00167 static void info_tailcall (lua_Debug *ar) {
    00168   ar->name = ar->namewhat = "";
    00169   ar->what = "tail";
    00170   ar->lastlinedefined = ar->linedefined = ar->currentline = -1;
    00171   ar->source = "=(tail call)";
    00172   luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
    00173   ar->nups = 0;
    00174 }
    00175
    00176
    00177 static void collectvalidlines (lua_State *L, Closure *f) {
    00178   if (f == NULL || f->c.isC) {
    00179     setnilvalue(L->top);
    00180   }
    00181   else {
    00182     Table *t = luaH_new(L, 0, 0);
    00183     int *lineinfo = f->l.p->lineinfo;
    00184     int i;
    00185     for (i=0; i<f->l.p->sizelineinfo; i++)
    00186       setbvalue(luaH_setnum(L, t, lineinfo[i]), 1);
    00187     sethvalue(L, L->top, t);
    00188   }
    00189   incr_top(L);
    00190 }
    00191
    00192
    00193 static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
    00194                     Closure *f, CallInfo *ci) {
    00195   int status = 1;
    00196   if (f == NULL) {
    00197     info_tailcall(ar);
    00198     return status;
    00199   }
    00200   for (; *what; what++) {
    00201     switch (*what) {
    00202       case 'S': {
    00203         funcinfo(ar, f);
    00204         break;
    00205       }
    00206       case 'l': {
    00207         ar->currentline = (ci) ? currentline(L, ci) : -1;
    00208         break;
    00209       }
    00210       case 'u': {
    00211         ar->nups = f->c.nupvalues;
    00212         break;
    00213       }
    00214       case 'n': {
    00215         ar->namewhat = (ci) ? getfuncname(L, ci, &ar->name) : NULL;
    00216         if (ar->namewhat == NULL) {
    00217           ar->namewhat = "";  /* not found */
    00218           ar->name = NULL;
    00219         }
    00220         break;
    00221       }
    00222       case 'L':
    00223       case 'f':  /* handled by lua_getinfo */
    00224         break;
    00225       default: status = 0;  /* invalid option */
    00226     }
    00227   }
    00228   return status;
    00229 }
    00230
    00231
    00232 LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
    00233   int status;
    00234   Closure *f = NULL;
    00235   CallInfo *ci = NULL;
    00236   lua_lock(L);
    00237   if (*what == '>') {
    00238     StkId func = L->top - 1;
    00239     luai_apicheck(L, ttisfunction(func));
    00240     what++;  /* skip the '>' */
    00241     f = clvalue(func);
    00242     L->top--;  /* pop function */
    00243   }
    00244   else if (ar->i_ci != 0) {  /* no tail call? */
    00245     ci = L->base_ci + ar->i_ci;
    00246     lua_assert(ttisfunction(ci->func));
    00247     f = clvalue(ci->func);
    00248   }
    00249   status = auxgetinfo(L, what, ar, f, ci);
    00250   if (strchr(what, 'f')) {
    00251     if (f == NULL) setnilvalue(L->top);
    00252     else setclvalue(L, L->top, f);
    00253     incr_top(L);
    00254   }
    00255   if (strchr(what, 'L'))
    00256     collectvalidlines(L, f);
    00257   lua_unlock(L);
    00258   return status;
    00259 }
    00260
    00261
    00262 /*
    00263 ** {======================================================
    00264 ** Symbolic Execution and code checker
    00265 ** =======================================================
    00266 */
    00267
    00268 #define check(x)                if (!(x)) return 0;
    00269
    00270 #define checkjump(pt,pc)        check(0 <= pc && pc < pt->sizecode)
    00271
    00272 #define checkreg(pt,reg)        check((reg) < (pt)->maxstacksize)
    00273
    00274
    00275
    00276 static int precheck (const Proto *pt) {
    00277   check(pt->maxstacksize <= MAXSTACK);
    00278   lua_assert(pt->numparams+(pt->is_vararg & VARARG_HASARG) <= pt->maxstacksize);
    00279   lua_assert(!(pt->is_vararg & VARARG_NEEDSARG) ||
    00280               (pt->is_vararg & VARARG_HASARG));
    00281   check(pt->sizeupvalues <= pt->nups);
    00282   check(pt->sizelineinfo == pt->sizecode || pt->sizelineinfo == 0);
    00283   check(GET_OPCODE(pt->code[pt->sizecode-1]) == OP_RETURN);
    00284   return 1;
    00285 }
    00286
    00287
    00288 #define checkopenop(pt,pc)      luaG_checkopenop((pt)->code[(pc)+1])
    00289
    00290 int luaG_checkopenop (Instruction i) {
    00291   switch (GET_OPCODE(i)) {
    00292     case OP_CALL:
    00293     case OP_TAILCALL:
    00294     case OP_RETURN:
    00295     case OP_SETLIST: {
    00296       check(GETARG_B(i) == 0);
    00297       return 1;
    00298     }
    00299     default: return 0;  /* invalid instruction after an open call */
    00300   }
    00301 }
    00302
    00303
    00304 static int checkArgMode (const Proto *pt, int r, enum OpArgMask mode) {
    00305   switch (mode) {
    00306     case OpArgN: check(r == 0); break;
    00307     case OpArgU: break;
    00308     case OpArgR: checkreg(pt, r); break;
    00309     case OpArgK:
    00310       check(ISK(r) ? INDEXK(r) < pt->sizek : r < pt->maxstacksize);
    00311       break;
    00312   }
    00313   return 1;
    00314 }
    00315
    00316
    00317 static Instruction symbexec (const Proto *pt, int lastpc, int reg) {
    00318   int pc;
    00319   int last;  /* stores position of last instruction that changed `reg' */
    00320   last = pt->sizecode-1;  /* points to final return (a `neutral' instruction) */
    00321   check(precheck(pt));
    00322   for (pc = 0; pc < lastpc; pc++) {
    00323     Instruction i = pt->code[pc];
    00324     OpCode op = GET_OPCODE(i);
    00325     int a = GETARG_A(i);
    00326     int b = 0;
    00327     int c = 0;
    00328     check(op < NUM_OPCODES);
    00329     checkreg(pt, a);
    00330     switch (getOpMode(op)) {
    00331       case iABC: {
    00332         b = GETARG_B(i);
    00333         c = GETARG_C(i);
    00334         check(checkArgMode(pt, b, getBMode(op)));
    00335         check(checkArgMode(pt, c, getCMode(op)));
    00336         break;
    00337       }
    00338       case iABx: {
    00339         b = GETARG_Bx(i);
    00340         if (getBMode(op) == OpArgK) check(b < pt->sizek);
    00341         break;
    00342       }
    00343       case iAsBx: {
    00344         b = GETARG_sBx(i);
    00345         if (getBMode(op) == OpArgR) {
    00346           int dest = pc+1+b;
    00347           check(0 <= dest && dest < pt->sizecode);
    00348           if (dest > 0) {
    00349             /* cannot jump to a setlist count */
    00350             Instruction d = pt->code[dest-1];
    00351             check(!(GET_OPCODE(d) == OP_SETLIST && GETARG_C(d) == 0));
    00352           }
    00353         }
    00354         break;
    00355       }
    00356     }
    00357     if (testAMode(op)) {
    00358       if (a == reg) last = pc;  /* change register `a' */
    00359     }
    00360     if (testTMode(op)) {
    00361       check(pc+2 < pt->sizecode);  /* check skip */
    00362       check(GET_OPCODE(pt->code[pc+1]) == OP_JMP);
    00363     }
    00364     switch (op) {
    00365       case OP_LOADBOOL: {
    00366         check(c == 0 || pc+2 < pt->sizecode);  /* check its jump */
    00367         break;
    00368       }
    00369       case OP_LOADNIL: {
    00370         if (a <= reg && reg <= b)
    00371           last = pc;  /* set registers from `a' to `b' */
    00372         break;
    00373       }
    00374       case OP_GETUPVAL:
    00375       case OP_SETUPVAL: {
    00376         check(b < pt->nups);
    00377         break;
    00378       }
    00379       case OP_GETGLOBAL:
    00380       case OP_SETGLOBAL: {
    00381         check(ttisstring(&pt->k[b]));
    00382         break;
    00383       }
    00384       case OP_SELF: {
    00385         checkreg(pt, a+1);
    00386         if (reg == a+1) last = pc;
    00387         break;
    00388       }
    00389       case OP_CONCAT: {
    00390         check(b < c);  /* at least two operands */
    00391         break;
    00392       }
    00393       case OP_TFORLOOP: {
    00394         check(c >= 1);  /* at least one result (control variable) */
    00395         checkreg(pt, a+2+c);  /* space for results */
    00396         if (reg >= a+2) last = pc;  /* affect all regs above its base */
    00397         break;
    00398       }
    00399       case OP_FORLOOP:
    00400       case OP_FORPREP:
    00401         checkreg(pt, a+3);
    00402         /* go through */
    00403       case OP_JMP: {
    00404         int dest = pc+1+b;
    00405         /* not full check and jump is forward and do not skip `lastpc'? */
    00406         if (reg != NO_REG && pc < dest && dest <= lastpc)
    00407           pc += b;  /* do the jump */
    00408         break;
    00409       }
    00410       case OP_CALL:
    00411       case OP_TAILCALL: {
    00412         if (b != 0) {
    00413           checkreg(pt, a+b-1);
    00414         }
    00415         c--;  /* c = num. returns */
    00416         if (c == LUA_MULTRET) {
    00417           check(checkopenop(pt, pc));
    00418         }
    00419         else if (c != 0)
    00420           checkreg(pt, a+c-1);
    00421         if (reg >= a) last = pc;  /* affect all registers above base */
    00422         break;
    00423       }
    00424       case OP_RETURN: {
    00425         b--;  /* b = num. returns */
    00426         if (b > 0) checkreg(pt, a+b-1);
    00427         break;
    00428       }
    00429       case OP_SETLIST: {
    00430         if (b > 0) checkreg(pt, a + b);
    00431         if (c == 0) pc++;
    00432         break;
    00433       }
    00434       case OP_CLOSURE: {
    00435         int nup, j;
    00436         check(b < pt->sizep);
    00437         nup = pt->p[b]->nups;
    00438         check(pc + nup < pt->sizecode);
    00439         for (j = 1; j <= nup; j++) {
    00440           OpCode op1 = GET_OPCODE(pt->code[pc + j]);
    00441           check(op1 == OP_GETUPVAL || op1 == OP_MOVE);
    00442         }
    00443         if (reg != NO_REG)  /* tracing? */
    00444           pc += nup;  /* do not 'execute' these pseudo-instructions */
    00445         break;
    00446       }
    00447       case OP_VARARG: {
    00448         check((pt->is_vararg & VARARG_ISVARARG) &&
    00449              !(pt->is_vararg & VARARG_NEEDSARG));
    00450         b--;
    00451         if (b == LUA_MULTRET) check(checkopenop(pt, pc));
    00452         checkreg(pt, a+b-1);
    00453         break;
    00454       }
    00455       default: break;
    00456     }
    00457   }
    00458   return pt->code[last];
    00459 }
    00460
    00461 #undef check
    00462 #undef checkjump
    00463 #undef checkreg
    00464
    00465 /* }====================================================== */
    00466
    00467
    00468 int luaG_checkcode (const Proto *pt) {
    00469   return (symbexec(pt, pt->sizecode, NO_REG) != 0);
    00470 }
    00471
    00472
    00473 static const char *kname (Proto *p, int c) {
    00474   if (ISK(c) && ttisstring(&p->k[INDEXK(c)]))
    00475     return svalue(&p->k[INDEXK(c)]);
    00476   else
    00477     return "?";
    00478 }
    00479
    00480
    00481 static const char *getobjname (lua_State *L, CallInfo *ci, int stackpos,
    00482                                const char **name) {
    00483   if (isLua(ci)) {  /* a Lua function? */
    00484     Proto *p = ci_func(ci)->l.p;
    00485     int pc = currentpc(L, ci);
    00486     Instruction i;
    00487     *name = luaF_getlocalname(p, stackpos+1, pc);
    00488     if (*name)  /* is a local? */
    00489       return "local";
    00490     i = symbexec(p, pc, stackpos);  /* try symbolic execution */
    00491     lua_assert(pc != -1);
    00492     switch (GET_OPCODE(i)) {
    00493       case OP_GETGLOBAL: {
    00494         int g = GETARG_Bx(i);  /* global index */
    00495         lua_assert(ttisstring(&p->k[g]));
    00496         *name = svalue(&p->k[g]);
    00497         return "global";
    00498       }
    00499       case OP_MOVE: {
    00500         int a = GETARG_A(i);
    00501         int b = GETARG_B(i);  /* move from `b' to `a' */
    00502         if (b < a)
    00503           return getobjname(L, ci, b, name);  /* get name for `b' */
    00504         break;
    00505       }
    00506       case OP_GETTABLE: {
    00507         int k = GETARG_C(i);  /* key index */
    00508         *name = kname(p, k);
    00509         return "field";
    00510       }
    00511       case OP_GETUPVAL: {
    00512         int u = GETARG_B(i);  /* upvalue index */
    00513         *name = p->upvalues ? getstr(p->upvalues[u]) : "?";
    00514         return "upvalue";
    00515       }
    00516       case OP_SELF: {
    00517         int k = GETARG_C(i);  /* key index */
    00518         *name = kname(p, k);
    00519         return "method";
    00520       }
    00521       default: break;
    00522     }
    00523   }
    00524   return NULL;  /* no useful name found */
    00525 }
    00526
    00527
    00528 static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
    00529   Instruction i;
    00530   if ((isLua(ci) && ci->tailcalls > 0) || !isLua(ci - 1))
    00531     return NULL;  /* calling function is not Lua (or is unknown) */
    00532   ci--;  /* calling function */
    00533   i = ci_func(ci)->l.p->code[currentpc(L, ci)];
    00534   if (GET_OPCODE(i) == OP_CALL || GET_OPCODE(i) == OP_TAILCALL ||
    00535       GET_OPCODE(i) == OP_TFORLOOP)
    00536     return getobjname(L, ci, GETARG_A(i), name);
    00537   else
    00538     return NULL;  /* no useful name can be found */
    00539 }
    00540
    00541
    00542 /* only ANSI way to check whether a pointer points to an array */
    00543 static int isinstack (CallInfo *ci, const TValue *o) {
    00544   StkId p;
    00545   for (p = ci->base; p < ci->top; p++)
    00546     if (o == p) return 1;
    00547   return 0;
    00548 }
    00549
    00550
    00551 void luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
    00552   const char *name = NULL;
    00553   const char *t = luaT_typenames[ttype(o)];
    00554   const char *kind = (isinstack(L->ci, o)) ?
    00555                          getobjname(L, L->ci, cast_int(o - L->base), &name) :
    00556                          NULL;
    00557   if (kind)
    00558     luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
    00559                 op, kind, name, t);
    00560   else
    00561     luaG_runerror(L, "attempt to %s a %s value", op, t);
    00562 }
    00563
    00564
    00565 void luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
    00566   if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
    00567   lua_assert(!ttisstring(p1) && !ttisnumber(p1));
    00568   luaG_typeerror(L, p1, "concatenate");
    00569 }
    00570
    00571
    00572 void luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
    00573   TValue temp;
    00574   if (luaV_tonumber(p1, &temp) == NULL)
    00575     p2 = p1;  /* first operand is wrong */
    00576   luaG_typeerror(L, p2, "perform arithmetic on");
    00577 }
    00578
    00579
    00580 int luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
    00581   const char *t1 = luaT_typenames[ttype(p1)];
    00582   const char *t2 = luaT_typenames[ttype(p2)];
    00583   if (t1[2] == t2[2])
    00584     luaG_runerror(L, "attempt to compare two %s values", t1);
    00585   else
    00586     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
    00587   return 0;
    00588 }
    00589
    00590
    00591 static void addinfo (lua_State *L, const char *msg) {
    00592   CallInfo *ci = L->ci;
    00593   if (isLua(ci)) {  /* is Lua code? */
    00594     char buff[LUA_IDSIZE];  /* add file:line information */
    00595     int line = currentline(L, ci);
    00596     luaO_chunkid(buff, getstr(getluaproto(ci)->source), LUA_IDSIZE);
    00597     luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
    00598   }
    00599 }
    00600
    00601
    00602 void luaG_errormsg (lua_State *L) {
    00603   if (L->errfunc != 0) {  /* is there an error handling function? */
    00604     StkId errfunc = restorestack(L, L->errfunc);
    00605     if (!ttisfunction(errfunc)) luaD_throw(L, LUA_ERRERR);
    00606     setobjs2s(L, L->top, L->top - 1);  /* move argument */
    00607     setobjs2s(L, L->top - 1, errfunc);  /* push function */
    00608     incr_top(L);
    00609     luaD_call(L, L->top - 2, 1);  /* call it */
    00610   }
    00611   luaD_throw(L, LUA_ERRRUN);
    00612 }
    00613
    00614
    00615 void luaG_runerror (lua_State *L, const char *fmt, ...) {
    00616   va_list argp;
    00617   va_start(argp, fmt);
    00618   addinfo(L, luaO_pushvfstring(L, fmt, argp));
    00619   va_end(argp);
    00620   luaG_errormsg(L);
    00621 }
    00622