xref: /netbsd-src/external/mit/lua/dist/src/ldebug.c (revision ba65fde2d7fefa7d39838fa5fa855e62bd606b5e) 
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 
641