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** $Id: ldebug.c,v 2.90 2012/08/16 17:34:28 roberto Exp $
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** See Copyright Notice in lua.h
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#define noLuaClosure(f) ((f) == NULL || (f)->c.tt == LUA_TCCL)
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static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name);
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static int currentpc (CallInfo *ci) {
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lua_assert(isLua(ci));
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return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
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static int currentline (CallInfo *ci) {
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return getfuncline(ci_func(ci)->p, currentpc(ci));
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** this function can be called asynchronous (e.g. during a signal)
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LUA_API int lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
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if (func == NULL || mask == 0) { /* turn off hooks? */
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L->oldpc = L->ci->u.l.savedpc;
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L->basehookcount = count;
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L->hookmask = cast_byte(mask);
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LUA_API lua_Hook lua_gethook (lua_State *L) {
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LUA_API int lua_gethookmask (lua_State *L) {
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LUA_API int lua_gethookcount (lua_State *L) {
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return L->basehookcount;
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LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
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if (level < 0) return 0; /* invalid (negative) level */
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for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
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if (level == 0 && ci != &L->base_ci) { /* level found? */
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else status = 0; /* no such level */
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static const char *upvalname (Proto *p, int uv) {
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TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
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if (s == NULL) return "?";
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else return getstr(s);
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static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
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int nparams = clLvalue(ci->func)->p->numparams;
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if (n >= ci->u.l.base - ci->func - nparams)
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return NULL; /* no such vararg */
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*pos = ci->func + nparams + n;
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return "(*vararg)"; /* generic name for any vararg */
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static const char *findlocal (lua_State *L, CallInfo *ci, int n,
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const char *name = NULL;
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if (n < 0) /* access to vararg values? */
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return findvararg(ci, -n, pos);
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name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
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if (name == NULL) { /* no 'standard' name? */
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StkId limit = (ci == L->ci) ? L->top : ci->next->func;
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if (limit - base >= n && n > 0) /* is 'n' inside 'ci' stack? */
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name = "(*temporary)"; /* generic name for any valid slot */
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return NULL; /* no name */
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*pos = base + (n - 1);
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LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
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if (ar == NULL) { /* information about non-active function? */
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if (!isLfunction(L->top - 1)) /* not a Lua function? */
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else /* consider live variables at function start (parameters) */
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name = luaF_getlocalname(clLvalue(L->top - 1)->p, n, 0);
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else { /* active function; get information through 'ar' */
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StkId pos = 0; /* to avoid warnings */
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name = findlocal(L, ar->i_ci, n, &pos);
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setobj2s(L, L->top, pos);
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LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
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StkId pos = 0; /* to avoid warnings */
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const char *name = findlocal(L, ar->i_ci, n, &pos);
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setobjs2s(L, pos, L->top - 1);
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L->top--; /* pop value */
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static void funcinfo (lua_Debug *ar, Closure *cl) {
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if (noLuaClosure(cl)) {
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ar->linedefined = -1;
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ar->lastlinedefined = -1;
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ar->source = p->source ? getstr(p->source) : "=?";
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ar->linedefined = p->linedefined;
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ar->lastlinedefined = p->lastlinedefined;
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ar->what = (ar->linedefined == 0) ? "main" : "Lua";
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luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
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static void collectvalidlines (lua_State *L, Closure *f) {
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if (noLuaClosure(f)) {
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int *lineinfo = f->l.p->lineinfo;
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Table *t = luaH_new(L); /* new table to store active lines */
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sethvalue(L, L->top, t); /* push it on stack */
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setbvalue(&v, 1); /* boolean 'true' to be the value of all indices */
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for (i = 0; i < f->l.p->sizelineinfo; i++) /* for all lines with code */
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luaH_setint(L, t, lineinfo[i], &v); /* table[line] = true */
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static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
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Closure *f, CallInfo *ci) {
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for (; *what; what++) {
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ar->currentline = (ci && isLua(ci)) ? currentline(ci) : -1;
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ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
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if (noLuaClosure(f)) {
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ar->isvararg = f->l.p->is_vararg;
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ar->nparams = f->l.p->numparams;
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ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
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/* calling function is a known Lua function? */
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if (ci && !(ci->callstatus & CIST_TAIL) && isLua(ci->previous))
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ar->namewhat = getfuncname(L, ci->previous, &ar->name);
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if (ar->namewhat == NULL) {
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ar->namewhat = ""; /* not found */
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case 'f': /* handled by lua_getinfo */
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default: status = 0; /* invalid option */
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LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
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api_check(L, ttisfunction(func), "function expected");
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what++; /* skip the '>' */
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L->top--; /* pop function */
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lua_assert(ttisfunction(ci->func));
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cl = ttisclosure(func) ? clvalue(func) : NULL;
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status = auxgetinfo(L, what, ar, cl, ci);
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if (strchr(what, 'f')) {
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setobjs2s(L, L->top, func);
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if (strchr(what, 'L'))
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collectvalidlines(L, cl);
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** {======================================================
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** Symbolic Execution
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** =======================================================
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static const char *getobjname (Proto *p, int lastpc, int reg,
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** find a "name" for the RK value 'c'
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static void kname (Proto *p, int pc, int c, const char **name) {
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if (ISK(c)) { /* is 'c' a constant? */
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TValue *kvalue = &p->k[INDEXK(c)];
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if (ttisstring(kvalue)) { /* literal constant? */
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*name = svalue(kvalue); /* it is its own name */
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/* else no reasonable name found */
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else { /* 'c' is a register */
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const char *what = getobjname(p, pc, c, name); /* search for 'c' */
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if (what && *what == 'c') { /* found a constant name? */
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return; /* 'name' already filled */
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/* else no reasonable name found */
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*name = "?"; /* no reasonable name found */
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** try to find last instruction before 'lastpc' that modified register 'reg'
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static int findsetreg (Proto *p, int lastpc, int reg) {
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int setreg = -1; /* keep last instruction that changed 'reg' */
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for (pc = 0; pc < lastpc; pc++) {
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Instruction i = p->code[pc];
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OpCode op = GET_OPCODE(i);
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if (a <= reg && reg <= a + b) /* set registers from 'a' to 'a+b' */
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if (reg >= a + 2) setreg = pc; /* affect all regs above its base */
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if (reg >= a) setreg = pc; /* affect all registers above base */
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int b = GETARG_sBx(i);
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int dest = pc + 1 + b;
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/* jump is forward and do not skip `lastpc'? */
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if (pc < dest && dest <= lastpc)
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pc += b; /* do the jump */
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if (reg == a) setreg = pc; /* jumped code can change 'a' */
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if (testAMode(op) && reg == a) /* any instruction that set A */
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static const char *getobjname (Proto *p, int lastpc, int reg,
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*name = luaF_getlocalname(p, reg + 1, lastpc);
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if (*name) /* is a local? */
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/* else try symbolic execution */
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pc = findsetreg(p, lastpc, reg);
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if (pc != -1) { /* could find instruction? */
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Instruction i = p->code[pc];
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OpCode op = GET_OPCODE(i);
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int b = GETARG_B(i); /* move from 'b' to 'a' */
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return getobjname(p, pc, b, name); /* get name for 'b' */
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int k = GETARG_C(i); /* key index */
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int t = GETARG_B(i); /* table index */
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const char *vn = (op == OP_GETTABLE) /* name of indexed variable */
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? luaF_getlocalname(p, t + 1, pc)
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kname(p, pc, k, name);
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return (vn && strcmp(vn, LUA_ENV) == 0) ? "global" : "field";
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*name = upvalname(p, GETARG_B(i));
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int b = (op == OP_LOADK) ? GETARG_Bx(i)
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: GETARG_Ax(p->code[pc + 1]);
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if (ttisstring(&p->k[b])) {
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*name = svalue(&p->k[b]);
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int k = GETARG_C(i); /* key index */
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kname(p, pc, k, name);
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default: break; /* go through to return NULL */
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return NULL; /* could not find reasonable name */
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static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
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Proto *p = ci_func(ci)->p; /* calling function */
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int pc = currentpc(ci); /* calling instruction index */
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Instruction i = p->code[pc]; /* calling instruction */
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switch (GET_OPCODE(i)) {
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case OP_TAILCALL: /* get function name */
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return getobjname(p, pc, GETARG_A(i), name);
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case OP_TFORCALL: { /* for iterator */
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*name = "for iterator";
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return "for iterator";
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/* all other instructions can call only through metamethods */
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case OP_GETTABLE: tm = TM_INDEX; break;
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case OP_SETTABLE: tm = TM_NEWINDEX; break;
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case OP_EQ: tm = TM_EQ; break;
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case OP_ADD: tm = TM_ADD; break;
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case OP_SUB: tm = TM_SUB; break;
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case OP_MUL: tm = TM_MUL; break;
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case OP_DIV: tm = TM_DIV; break;
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case OP_MOD: tm = TM_MOD; break;
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case OP_POW: tm = TM_POW; break;
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case OP_UNM: tm = TM_UNM; break;
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case OP_LEN: tm = TM_LEN; break;
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case OP_LT: tm = TM_LT; break;
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case OP_LE: tm = TM_LE; break;
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case OP_CONCAT: tm = TM_CONCAT; break;
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return NULL; /* else no useful name can be found */
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*name = getstr(G(L)->tmname[tm]);
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/* }====================================================== */
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** only ANSI way to check whether a pointer points to an array
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** (used only for error messages, so efficiency is not a big concern)
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static int isinstack (CallInfo *ci, const TValue *o) {
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for (p = ci->u.l.base; p < ci->top; p++)
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if (o == p) return 1;
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static const char *getupvalname (CallInfo *ci, const TValue *o,
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LClosure *c = ci_func(ci);
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for (i = 0; i < c->nupvalues; i++) {
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if (c->upvals[i]->v == o) {
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*name = upvalname(c->p, i);
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l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
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CallInfo *ci = L->ci;
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const char *name = NULL;
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const char *t = objtypename(o);
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const char *kind = NULL;
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kind = getupvalname(ci, o, &name); /* check whether 'o' is an upvalue */
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if (!kind && isinstack(ci, o)) /* no? try a register */
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kind = getobjname(ci_func(ci)->p, currentpc(ci),
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cast_int(o - ci->u.l.base), &name);
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luaG_runerror(L, "attempt to %s %s " LUA_QS " (a %s value)",
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luaG_runerror(L, "attempt to %s a %s value", op, t);
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l_noret luaG_concaterror (lua_State *L, StkId p1, StkId p2) {
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if (ttisstring(p1) || ttisnumber(p1)) p1 = p2;
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lua_assert(!ttisstring(p1) && !ttisnumber(p2));
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luaG_typeerror(L, p1, "concatenate");
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l_noret luaG_aritherror (lua_State *L, const TValue *p1, const TValue *p2) {
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if (luaV_tonumber(p1, &temp) == NULL)
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p2 = p1; /* first operand is wrong */
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luaG_typeerror(L, p2, "perform arithmetic on");
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l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
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const char *t1 = objtypename(p1);
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const char *t2 = objtypename(p2);
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luaG_runerror(L, "attempt to compare two %s values", t1);
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luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
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static void addinfo (lua_State *L, const char *msg) {
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CallInfo *ci = L->ci;
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if (isLua(ci)) { /* is Lua code? */
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char buff[LUA_IDSIZE]; /* add file:line information */
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int line = currentline(ci);
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TString *src = ci_func(ci)->p->source;
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luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
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else { /* no source available; use "?" instead */
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buff[0] = '?'; buff[1] = '\0';
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luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
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l_noret luaG_errormsg (lua_State *L) {
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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 */
567
luaD_call(L, L->top - 2, 1, 0); /* call it */
569
luaD_throw(L, LUA_ERRRUN);
573
l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
576
addinfo(L, luaO_pushvfstring(L, fmt, argp));