1/*
2** $Id: ldebug.c $
3** Debug Interface
4** See Copyright Notice in lua.h
5*/
6
7#define ldebug_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <stdarg.h>
14#include <stddef.h>
15#include <string.h>
16
17#include "lua.h"
18
19#include "lapi.h"
20#include "lcode.h"
21#include "ldebug.h"
22#include "ldo.h"
23#include "lfunc.h"
24#include "lobject.h"
25#include "lopcodes.h"
26#include "lstate.h"
27#include "lstring.h"
28#include "ltable.h"
29#include "ltm.h"
30#include "lvm.h"
31
32
33
34#define LuaClosure(f) ((f) != NULL && (f)->c.tt == LUA_VLCL)
35
36
37static const char *funcnamefromcall (lua_State *L, CallInfo *ci,
38 const char **name);
39
40
41static int currentpc (CallInfo *ci) {
42 lua_assert(isLua(ci));
43 return pcRel(ci->u.l.savedpc, ci_func(ci)->p);
44}
45
46
47/*
48** Get a "base line" to find the line corresponding to an instruction.
49** Base lines are regularly placed at MAXIWTHABS intervals, so usually
50** an integer division gets the right place. When the source file has
51** large sequences of empty/comment lines, it may need extra entries,
52** so the original estimate needs a correction.
53** If the original estimate is -1, the initial 'if' ensures that the
54** 'while' will run at least once.
55** The assertion that the estimate is a lower bound for the correct base
56** is valid as long as the debug info has been generated with the same
57** value for MAXIWTHABS or smaller. (Previous releases use a little
58** smaller value.)
59*/
60static int getbaseline (const Proto *f, int pc, int *basepc) {
61 if (f->sizeabslineinfo == 0 || pc < f->abslineinfo[0].pc) {
62 *basepc = -1; /* start from the beginning */
63 return f->linedefined;
64 }
65 else {
66 int i = cast_uint(pc) / MAXIWTHABS - 1; /* get an estimate */
67 /* estimate must be a lower bound of the correct base */
68 lua_assert(i < 0 ||
69 (i < f->sizeabslineinfo && f->abslineinfo[i].pc <= pc));
70 while (i + 1 < f->sizeabslineinfo && pc >= f->abslineinfo[i + 1].pc)
71 i++; /* low estimate; adjust it */
72 *basepc = f->abslineinfo[i].pc;
73 return f->abslineinfo[i].line;
74 }
75}
76
77
78/*
79** Get the line corresponding to instruction 'pc' in function 'f';
80** first gets a base line and from there does the increments until
81** the desired instruction.
82*/
83int luaG_getfuncline (const Proto *f, int pc) {
84 if (f->lineinfo == NULL) /* no debug information? */
85 return -1;
86 else {
87 int basepc;
88 int baseline = getbaseline(f, pc, &basepc);
89 while (basepc++ < pc) { /* walk until given instruction */
90 lua_assert(f->lineinfo[basepc] != ABSLINEINFO);
91 baseline += f->lineinfo[basepc]; /* correct line */
92 }
93 return baseline;
94 }
95}
96
97
98static int getcurrentline (CallInfo *ci) {
99 return luaG_getfuncline(ci_func(ci)->p, currentpc(ci));
100}
101
102
103/*
104** Set 'trap' for all active Lua frames.
105** This function can be called during a signal, under "reasonable"
106** assumptions. A new 'ci' is completely linked in the list before it
107** becomes part of the "active" list, and we assume that pointers are
108** atomic; see comment in next function.
109** (A compiler doing interprocedural optimizations could, theoretically,
110** reorder memory writes in such a way that the list could be
111** temporarily broken while inserting a new element. We simply assume it
112** has no good reasons to do that.)
113*/
114static void settraps (CallInfo *ci) {
115 for (; ci != NULL; ci = ci->previous)
116 if (isLua(ci))
117 ci->u.l.trap = 1;
118}
119
120
121/*
122** This function can be called during a signal, under "reasonable"
123** assumptions.
124** Fields 'basehookcount' and 'hookcount' (set by 'resethookcount')
125** are for debug only, and it is no problem if they get arbitrary
126** values (causes at most one wrong hook call). 'hookmask' is an atomic
127** value. We assume that pointers are atomic too (e.g., gcc ensures that
128** for all platforms where it runs). Moreover, 'hook' is always checked
129** before being called (see 'luaD_hook').
130*/
131LUA_API void lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
132 if (func == NULL || mask == 0) { /* turn off hooks? */
133 mask = 0;
134 func = NULL;
135 }
136 L->hook = func;
137 L->basehookcount = count;
138 resethookcount(L);
139 L->hookmask = cast_byte(mask);
140 if (mask)
141 settraps(L->ci); /* to trace inside 'luaV_execute' */
142}
143
144
145LUA_API lua_Hook lua_gethook (lua_State *L) {
146 return L->hook;
147}
148
149
150LUA_API int lua_gethookmask (lua_State *L) {
151 return L->hookmask;
152}
153
154
155LUA_API int lua_gethookcount (lua_State *L) {
156 return L->basehookcount;
157}
158
159
160LUA_API int lua_getstack (lua_State *L, int level, lua_Debug *ar) {
161 int status;
162 CallInfo *ci;
163 if (level < 0) return 0; /* invalid (negative) level */
164 lua_lock(L);
165 for (ci = L->ci; level > 0 && ci != &L->base_ci; ci = ci->previous)
166 level--;
167 if (level == 0 && ci != &L->base_ci) { /* level found? */
168 status = 1;
169 ar->i_ci = ci;
170 }
171 else status = 0; /* no such level */
172 lua_unlock(L);
173 return status;
174}
175
176
177static const char *upvalname (const Proto *p, int uv) {
178 TString *s = check_exp(uv < p->sizeupvalues, p->upvalues[uv].name);
179 if (s == NULL) return "?";
180 else return getstr(s);
181}
182
183
184static const char *findvararg (CallInfo *ci, int n, StkId *pos) {
185 if (clLvalue(s2v(ci->func.p))->p->is_vararg) {
186 int nextra = ci->u.l.nextraargs;
187 if (n >= -nextra) { /* 'n' is negative */
188 *pos = ci->func.p - nextra - (n + 1);
189 return "(vararg)"; /* generic name for any vararg */
190 }
191 }
192 return NULL; /* no such vararg */
193}
194
195
196const char *luaG_findlocal (lua_State *L, CallInfo *ci, int n, StkId *pos) {
197 StkId base = ci->func.p + 1;
198 const char *name = NULL;
199 if (isLua(ci)) {
200 if (n < 0) /* access to vararg values? */
201 return findvararg(ci, n, pos);
202 else
203 name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));
204 }
205 if (name == NULL) { /* no 'standard' name? */
206 StkId limit = (ci == L->ci) ? L->top.p : ci->next->func.p;
207 if (limit - base >= n && n > 0) { /* is 'n' inside 'ci' stack? */
208 /* generic name for any valid slot */
209 name = isLua(ci) ? "(temporary)" : "(C temporary)";
210 }
211 else
212 return NULL; /* no name */
213 }
214 if (pos)
215 *pos = base + (n - 1);
216 return name;
217}
218
219
220LUA_API const char *lua_getlocal (lua_State *L, const lua_Debug *ar, int n) {
221 const char *name;
222 lua_lock(L);
223 if (ar == NULL) { /* information about non-active function? */
224 if (!isLfunction(s2v(L->top.p - 1))) /* not a Lua function? */
225 name = NULL;
226 else /* consider live variables at function start (parameters) */
227 name = luaF_getlocalname(clLvalue(s2v(L->top.p - 1))->p, n, 0);
228 }
229 else { /* active function; get information through 'ar' */
230 StkId pos = NULL; /* to avoid warnings */
231 name = luaG_findlocal(L, ar->i_ci, n, &pos);
232 if (name) {
233 setobjs2s(L, L->top.p, pos);
234 api_incr_top(L);
235 }
236 }
237 lua_unlock(L);
238 return name;
239}
240
241
242LUA_API const char *lua_setlocal (lua_State *L, const lua_Debug *ar, int n) {
243 StkId pos = NULL; /* to avoid warnings */
244 const char *name;
245 lua_lock(L);
246 name = luaG_findlocal(L, ar->i_ci, n, &pos);
247 if (name) {
248 setobjs2s(L, pos, L->top.p - 1);
249 L->top.p--; /* pop value */
250 }
251 lua_unlock(L);
252 return name;
253}
254
255
256static void funcinfo (lua_Debug *ar, Closure *cl) {
257 if (!LuaClosure(cl)) {
258 ar->source = "=[C]";
259 ar->srclen = LL("=[C]");
260 ar->linedefined = -1;
261 ar->lastlinedefined = -1;
262 ar->what = "C";
263 }
264 else {
265 const Proto *p = cl->l.p;
266 if (p->source) {
267 ar->source = getstr(p->source);
268 ar->srclen = tsslen(p->source);
269 }
270 else {
271 ar->source = "=?";
272 ar->srclen = LL("=?");
273 }
274 ar->linedefined = p->linedefined;
275 ar->lastlinedefined = p->lastlinedefined;
276 ar->what = (ar->linedefined == 0) ? "main" : "Lua";
277 }
278 luaO_chunkid(ar->short_src, ar->source, ar->srclen);
279}
280
281
282static int nextline (const Proto *p, int currentline, int pc) {
283 if (p->lineinfo[pc] != ABSLINEINFO)
284 return currentline + p->lineinfo[pc];
285 else
286 return luaG_getfuncline(p, pc);
287}
288
289
290static void collectvalidlines (lua_State *L, Closure *f) {
291 if (!LuaClosure(f)) {
292 setnilvalue(s2v(L->top.p));
293 api_incr_top(L);
294 }
295 else {
296 const Proto *p = f->l.p;
297 int currentline = p->linedefined;
298 Table *t = luaH_new(L); /* new table to store active lines */
299 sethvalue2s(L, L->top.p, t); /* push it on stack */
300 api_incr_top(L);
301 if (p->lineinfo != NULL) { /* proto with debug information? */
302 int i;
303 TValue v;
304 setbtvalue(&v); /* boolean 'true' to be the value of all indices */
305 if (!p->is_vararg) /* regular function? */
306 i = 0; /* consider all instructions */
307 else { /* vararg function */
308 lua_assert(GET_OPCODE(p->code[0]) == OP_VARARGPREP);
309 currentline = nextline(p, currentline, 0);
310 i = 1; /* skip first instruction (OP_VARARGPREP) */
311 }
312 for (; i < p->sizelineinfo; i++) { /* for each instruction */
313 currentline = nextline(p, currentline, i); /* get its line */
314 luaH_setint(L, t, currentline, &v); /* table[line] = true */
315 }
316 }
317 }
318}
319
320
321static const char *getfuncname (lua_State *L, CallInfo *ci, const char **name) {
322 /* calling function is a known function? */
323 if (ci != NULL && !(ci->callstatus & CIST_TAIL))
324 return funcnamefromcall(L, ci->previous, name);
325 else return NULL; /* no way to find a name */
326}
327
328
329static int auxgetinfo (lua_State *L, const char *what, lua_Debug *ar,
330 Closure *f, CallInfo *ci) {
331 int status = 1;
332 for (; *what; what++) {
333 switch (*what) {
334 case 'S': {
335 funcinfo(ar, f);
336 break;
337 }
338 case 'l': {
339 ar->currentline = (ci && isLua(ci)) ? getcurrentline(ci) : -1;
340 break;
341 }
342 case 'u': {
343 ar->nups = (f == NULL) ? 0 : f->c.nupvalues;
344 if (!LuaClosure(f)) {
345 ar->isvararg = 1;
346 ar->nparams = 0;
347 }
348 else {
349 ar->isvararg = f->l.p->is_vararg;
350 ar->nparams = f->l.p->numparams;
351 }
352 break;
353 }
354 case 't': {
355 ar->istailcall = (ci) ? ci->callstatus & CIST_TAIL : 0;
356 break;
357 }
358 case 'n': {
359 ar->namewhat = getfuncname(L, ci, &ar->name);
360 if (ar->namewhat == NULL) {
361 ar->namewhat = ""; /* not found */
362 ar->name = NULL;
363 }
364 break;
365 }
366 case 'r': {
367 if (ci == NULL || !(ci->callstatus & CIST_TRAN))
368 ar->ftransfer = ar->ntransfer = 0;
369 else {
370 ar->ftransfer = ci->u2.transferinfo.ftransfer;
371 ar->ntransfer = ci->u2.transferinfo.ntransfer;
372 }
373 break;
374 }
375 case 'L':
376 case 'f': /* handled by lua_getinfo */
377 break;
378 default: status = 0; /* invalid option */
379 }
380 }
381 return status;
382}
383
384
385LUA_API int lua_getinfo (lua_State *L, const char *what, lua_Debug *ar) {
386 int status;
387 Closure *cl;
388 CallInfo *ci;
389 TValue *func;
390 lua_lock(L);
391 if (*what == '>') {
392 ci = NULL;
393 func = s2v(L->top.p - 1);
394 api_check(L, ttisfunction(func), "function expected");
395 what++; /* skip the '>' */
396 L->top.p--; /* pop function */
397 }
398 else {
399 ci = ar->i_ci;
400 func = s2v(ci->func.p);
401 lua_assert(ttisfunction(func));
402 }
403 cl = ttisclosure(func) ? clvalue(func) : NULL;
404 status = auxgetinfo(L, what, ar, cl, ci);
405 if (strchr(what, 'f')) {
406 setobj2s(L, L->top.p, func);
407 api_incr_top(L);
408 }
409 if (strchr(what, 'L'))
410 collectvalidlines(L, cl);
411 lua_unlock(L);
412 return status;
413}
414
415
416/*
417** {======================================================
418** Symbolic Execution
419** =======================================================
420*/
421
422
423static int filterpc (int pc, int jmptarget) {
424 if (pc < jmptarget) /* is code conditional (inside a jump)? */
425 return -1; /* cannot know who sets that register */
426 else return pc; /* current position sets that register */
427}
428
429
430/*
431** Try to find last instruction before 'lastpc' that modified register 'reg'.
432*/
433static int findsetreg (const Proto *p, int lastpc, int reg) {
434 int pc;
435 int setreg = -1; /* keep last instruction that changed 'reg' */
436 int jmptarget = 0; /* any code before this address is conditional */
437 if (testMMMode(GET_OPCODE(p->code[lastpc])))
438 lastpc--; /* previous instruction was not actually executed */
439 for (pc = 0; pc < lastpc; pc++) {
440 Instruction i = p->code[pc];
441 OpCode op = GET_OPCODE(i);
442 int a = GETARG_A(i);
443 int change; /* true if current instruction changed 'reg' */
444 switch (op) {
445 case OP_LOADNIL: { /* set registers from 'a' to 'a+b' */
446 int b = GETARG_B(i);
447 change = (a <= reg && reg <= a + b);
448 break;
449 }
450 case OP_TFORCALL: { /* affect all regs above its base */
451 change = (reg >= a + 2);
452 break;
453 }
454 case OP_CALL:
455 case OP_TAILCALL: { /* affect all registers above base */
456 change = (reg >= a);
457 break;
458 }
459 case OP_JMP: { /* doesn't change registers, but changes 'jmptarget' */
460 int b = GETARG_sJ(i);
461 int dest = pc + 1 + b;
462 /* jump does not skip 'lastpc' and is larger than current one? */
463 if (dest <= lastpc && dest > jmptarget)
464 jmptarget = dest; /* update 'jmptarget' */
465 change = 0;
466 break;
467 }
468 default: /* any instruction that sets A */
469 change = (testAMode(op) && reg == a);
470 break;
471 }
472 if (change)
473 setreg = filterpc(pc, jmptarget);
474 }
475 return setreg;
476}
477
478
479/*
480** Find a "name" for the constant 'c'.
481*/
482static const char *kname (const Proto *p, int index, const char **name) {
483 TValue *kvalue = &p->k[index];
484 if (ttisstring(kvalue)) {
485 *name = getstr(tsvalue(kvalue));
486 return "constant";
487 }
488 else {
489 *name = "?";
490 return NULL;
491 }
492}
493
494
495static const char *basicgetobjname (const Proto *p, int *ppc, int reg,
496 const char **name) {
497 int pc = *ppc;
498 *name = luaF_getlocalname(p, reg + 1, pc);
499 if (*name) /* is a local? */
500 return "local";
501 /* else try symbolic execution */
502 *ppc = pc = findsetreg(p, pc, reg);
503 if (pc != -1) { /* could find instruction? */
504 Instruction i = p->code[pc];
505 OpCode op = GET_OPCODE(i);
506 switch (op) {
507 case OP_MOVE: {
508 int b = GETARG_B(i); /* move from 'b' to 'a' */
509 if (b < GETARG_A(i))
510 return basicgetobjname(p, ppc, b, name); /* get name for 'b' */
511 break;
512 }
513 case OP_GETUPVAL: {
514 *name = upvalname(p, GETARG_B(i));
515 return "upvalue";
516 }
517 case OP_LOADK: return kname(p, GETARG_Bx(i), name);
518 case OP_LOADKX: return kname(p, GETARG_Ax(p->code[pc + 1]), name);
519 default: break;
520 }
521 }
522 return NULL; /* could not find reasonable name */
523}
524
525
526/*
527** Find a "name" for the register 'c'.
528*/
529static void rname (const Proto *p, int pc, int c, const char **name) {
530 const char *what = basicgetobjname(p, &pc, c, name); /* search for 'c' */
531 if (!(what && *what == 'c')) /* did not find a constant name? */
532 *name = "?";
533}
534
535
536/*
537** Find a "name" for a 'C' value in an RK instruction.
538*/
539static void rkname (const Proto *p, int pc, Instruction i, const char **name) {
540 int c = GETARG_C(i); /* key index */
541 if (GETARG_k(i)) /* is 'c' a constant? */
542 kname(p, c, name);
543 else /* 'c' is a register */
544 rname(p, pc, c, name);
545}
546
547
548/*
549** Check whether table being indexed by instruction 'i' is the
550** environment '_ENV'
551*/
552static const char *isEnv (const Proto *p, int pc, Instruction i, int isup) {
553 int t = GETARG_B(i); /* table index */
554 const char *name; /* name of indexed variable */
555 if (isup) /* is 't' an upvalue? */
556 name = upvalname(p, t);
557 else /* 't' is a register */
558 basicgetobjname(p, &pc, t, &name);
559 return (name && strcmp(name, LUA_ENV) == 0) ? "global" : "field";
560}
561
562
563/*
564** Extend 'basicgetobjname' to handle table accesses
565*/
566static const char *getobjname (const Proto *p, int lastpc, int reg,
567 const char **name) {
568 const char *kind = basicgetobjname(p, &lastpc, reg, name);
569 if (kind != NULL)
570 return kind;
571 else if (lastpc != -1) { /* could find instruction? */
572 Instruction i = p->code[lastpc];
573 OpCode op = GET_OPCODE(i);
574 switch (op) {
575 case OP_GETTABUP: {
576 int k = GETARG_C(i); /* key index */
577 kname(p, k, name);
578 return isEnv(p, lastpc, i, 1);
579 }
580 case OP_GETTABLE: {
581 int k = GETARG_C(i); /* key index */
582 rname(p, lastpc, k, name);
583 return isEnv(p, lastpc, i, 0);
584 }
585 case OP_GETI: {
586 *name = "integer index";
587 return "field";
588 }
589 case OP_GETFIELD: {
590 int k = GETARG_C(i); /* key index */
591 kname(p, k, name);
592 return isEnv(p, lastpc, i, 0);
593 }
594 case OP_SELF: {
595 rkname(p, lastpc, i, name);
596 return "method";
597 }
598 default: break; /* go through to return NULL */
599 }
600 }
601 return NULL; /* could not find reasonable name */
602}
603
604
605/*
606** Try to find a name for a function based on the code that called it.
607** (Only works when function was called by a Lua function.)
608** Returns what the name is (e.g., "for iterator", "method",
609** "metamethod") and sets '*name' to point to the name.
610*/
611static const char *funcnamefromcode (lua_State *L, const Proto *p,
612 int pc, const char **name) {
613 TMS tm = (TMS)0; /* (initial value avoids warnings) */
614 Instruction i = p->code[pc]; /* calling instruction */
615 switch (GET_OPCODE(i)) {
616 case OP_CALL:
617 case OP_TAILCALL:
618 return getobjname(p, pc, GETARG_A(i), name); /* get function name */
619 case OP_TFORCALL: { /* for iterator */
620 *name = "for iterator";
621 return "for iterator";
622 }
623 /* other instructions can do calls through metamethods */
624 case OP_SELF: case OP_GETTABUP: case OP_GETTABLE:
625 case OP_GETI: case OP_GETFIELD:
626 tm = TM_INDEX;
627 break;
628 case OP_SETTABUP: case OP_SETTABLE: case OP_SETI: case OP_SETFIELD:
629 tm = TM_NEWINDEX;
630 break;
631 case OP_MMBIN: case OP_MMBINI: case OP_MMBINK: {
632 tm = cast(TMS, GETARG_C(i));
633 break;
634 }
635 case OP_UNM: tm = TM_UNM; break;
636 case OP_BNOT: tm = TM_BNOT; break;
637 case OP_LEN: tm = TM_LEN; break;
638 case OP_CONCAT: tm = TM_CONCAT; break;
639 case OP_EQ: tm = TM_EQ; break;
640 /* no cases for OP_EQI and OP_EQK, as they don't call metamethods */
641 case OP_LT: case OP_LTI: case OP_GTI: tm = TM_LT; break;
642 case OP_LE: case OP_LEI: case OP_GEI: tm = TM_LE; break;
643 case OP_CLOSE: case OP_RETURN: tm = TM_CLOSE; break;
644 default:
645 return NULL; /* cannot find a reasonable name */
646 }
647 *name = getshrstr(G(L)->tmname[tm]) + 2;
648 return "metamethod";
649}
650
651
652/*
653** Try to find a name for a function based on how it was called.
654*/
655static const char *funcnamefromcall (lua_State *L, CallInfo *ci,
656 const char **name) {
657 if (ci->callstatus & CIST_HOOKED) { /* was it called inside a hook? */
658 *name = "?";
659 return "hook";
660 }
661 else if (ci->callstatus & CIST_FIN) { /* was it called as a finalizer? */
662 *name = "__gc";
663 return "metamethod"; /* report it as such */
664 }
665 else if (isLua(ci))
666 return funcnamefromcode(L, ci_func(ci)->p, currentpc(ci), name);
667 else
668 return NULL;
669}
670
671/* }====================================================== */
672
673
674
675/*
676** Check whether pointer 'o' points to some value in the stack frame of
677** the current function and, if so, returns its index. Because 'o' may
678** not point to a value in this stack, we cannot compare it with the
679** region boundaries (undefined behavior in ISO C).
680*/
681static int instack (CallInfo *ci, const TValue *o) {
682 int pos;
683 StkId base = ci->func.p + 1;
684 for (pos = 0; base + pos < ci->top.p; pos++) {
685 if (o == s2v(base + pos))
686 return pos;
687 }
688 return -1; /* not found */
689}
690
691
692/*
693** Checks whether value 'o' came from an upvalue. (That can only happen
694** with instructions OP_GETTABUP/OP_SETTABUP, which operate directly on
695** upvalues.)
696*/
697static const char *getupvalname (CallInfo *ci, const TValue *o,
698 const char **name) {
699 LClosure *c = ci_func(ci);
700 int i;
701 for (i = 0; i < c->nupvalues; i++) {
702 if (c->upvals[i]->v.p == o) {
703 *name = upvalname(c->p, i);
704 return "upvalue";
705 }
706 }
707 return NULL;
708}
709
710
711static const char *formatvarinfo (lua_State *L, const char *kind,
712 const char *name) {
713 if (kind == NULL)
714 return ""; /* no information */
715 else
716 return luaO_pushfstring(L, " (%s '%s')", kind, name);
717}
718
719/*
720** Build a string with a "description" for the value 'o', such as
721** "variable 'x'" or "upvalue 'y'".
722*/
723static const char *varinfo (lua_State *L, const TValue *o) {
724 CallInfo *ci = L->ci;
725 const char *name = NULL; /* to avoid warnings */
726 const char *kind = NULL;
727 if (isLua(ci)) {
728 kind = getupvalname(ci, o, &name); /* check whether 'o' is an upvalue */
729 if (!kind) { /* not an upvalue? */
730 int reg = instack(ci, o); /* try a register */
731 if (reg >= 0) /* is 'o' a register? */
732 kind = getobjname(ci_func(ci)->p, currentpc(ci), reg, &name);
733 }
734 }
735 return formatvarinfo(L, kind, name);
736}
737
738
739/*
740** Raise a type error
741*/
742static l_noret typeerror (lua_State *L, const TValue *o, const char *op,
743 const char *extra) {
744 const char *t = luaT_objtypename(L, o);
745 luaG_runerror(L, "attempt to %s a %s value%s", op, t, extra);
746}
747
748
749/*
750** Raise a type error with "standard" information about the faulty
751** object 'o' (using 'varinfo').
752*/
753l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
754 typeerror(L, o, op, varinfo(L, o));
755}
756
757
758/*
759** Raise an error for calling a non-callable object. Try to find a name
760** for the object based on how it was called ('funcnamefromcall'); if it
761** cannot get a name there, try 'varinfo'.
762*/
763l_noret luaG_callerror (lua_State *L, const TValue *o) {
764 CallInfo *ci = L->ci;
765 const char *name = NULL; /* to avoid warnings */
766 const char *kind = funcnamefromcall(L, ci, &name);
767 const char *extra = kind ? formatvarinfo(L, kind, name) : varinfo(L, o);
768 typeerror(L, o, "call", extra);
769}
770
771
772l_noret luaG_forerror (lua_State *L, const TValue *o, const char *what) {
773 luaG_runerror(L, "bad 'for' %s (number expected, got %s)",
774 what, luaT_objtypename(L, o));
775}
776
777
778l_noret luaG_concaterror (lua_State *L, const TValue *p1, const TValue *p2) {
779 if (ttisstring(p1) || cvt2str(p1)) p1 = p2;
780 luaG_typeerror(L, p1, "concatenate");
781}
782
783
784l_noret luaG_opinterror (lua_State *L, const TValue *p1,
785 const TValue *p2, const char *msg) {
786 if (!ttisnumber(p1)) /* first operand is wrong? */
787 p2 = p1; /* now second is wrong */
788 luaG_typeerror(L, p2, msg);
789}
790
791
792/*
793** Error when both values are convertible to numbers, but not to integers
794*/
795l_noret luaG_tointerror (lua_State *L, const TValue *p1, const TValue *p2) {
796 lua_Integer temp;
797 if (!luaV_tointegerns(p1, &temp, LUA_FLOORN2I))
798 p2 = p1;
799 luaG_runerror(L, "number%s has no integer representation", varinfo(L, p2));
800}
801
802
803l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
804 const char *t1 = luaT_objtypename(L, p1);
805 const char *t2 = luaT_objtypename(L, p2);
806 if (strcmp(t1, t2) == 0)
807 luaG_runerror(L, "attempt to compare two %s values", t1);
808 else
809 luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
810}
811
812
813/* add src:line information to 'msg' */
814const char *luaG_addinfo (lua_State *L, const char *msg, TString *src,
815 int line) {
816 char buff[LUA_IDSIZE];
817 if (src)
818 luaO_chunkid(buff, getstr(src), tsslen(src));
819 else { /* no source available; use "?" instead */
820 buff[0] = '?'; buff[1] = '\0';
821 }
822 return luaO_pushfstring(L, "%s:%d: %s", buff, line, msg);
823}
824
825
826l_noret luaG_errormsg (lua_State *L) {
827 if (L->errfunc != 0) { /* is there an error handling function? */
828 StkId errfunc = restorestack(L, L->errfunc);
829 lua_assert(ttisfunction(s2v(errfunc)));
830 setobjs2s(L, L->top.p, L->top.p - 1); /* move argument */
831 setobjs2s(L, L->top.p - 1, errfunc); /* push function */
832 L->top.p++; /* assume EXTRA_STACK */
833 luaD_callnoyield(L, L->top.p - 2, 1); /* call it */
834 }
835 luaD_throw(L, LUA_ERRRUN);
836}
837
838
839l_noret luaG_runerror (lua_State *L, const char *fmt, ...) {
840 CallInfo *ci = L->ci;
841 const char *msg;
842 va_list argp;
843 luaC_checkGC(L); /* error message uses memory */
844 va_start(argp, fmt);
845 msg = luaO_pushvfstring(L, fmt, argp); /* format message */
846 va_end(argp);
847 if (isLua(ci)) { /* if Lua function, add source:line information */
848 luaG_addinfo(L, msg, ci_func(ci)->p->source, getcurrentline(ci));
849 setobjs2s(L, L->top.p - 2, L->top.p - 1); /* remove 'msg' */
850 L->top.p--;
851 }
852 luaG_errormsg(L);
853}
854
855
856/*
857** Check whether new instruction 'newpc' is in a different line from
858** previous instruction 'oldpc'. More often than not, 'newpc' is only
859** one or a few instructions after 'oldpc' (it must be after, see
860** caller), so try to avoid calling 'luaG_getfuncline'. If they are
861** too far apart, there is a good chance of a ABSLINEINFO in the way,
862** so it goes directly to 'luaG_getfuncline'.
863*/
864static int changedline (const Proto *p, int oldpc, int newpc) {
865 if (p->lineinfo == NULL) /* no debug information? */
866 return 0;
867 if (newpc - oldpc < MAXIWTHABS / 2) { /* not too far apart? */
868 int delta = 0; /* line difference */
869 int pc = oldpc;
870 for (;;) {
871 int lineinfo = p->lineinfo[++pc];
872 if (lineinfo == ABSLINEINFO)
873 break; /* cannot compute delta; fall through */
874 delta += lineinfo;
875 if (pc == newpc)
876 return (delta != 0); /* delta computed successfully */
877 }
878 }
879 /* either instructions are too far apart or there is an absolute line
880 info in the way; compute line difference explicitly */
881 return (luaG_getfuncline(p, oldpc) != luaG_getfuncline(p, newpc));
882}
883
884
885/*
886** Traces Lua calls. If code is running the first instruction of a function,
887** and function is not vararg, and it is not coming from an yield,
888** calls 'luaD_hookcall'. (Vararg functions will call 'luaD_hookcall'
889** after adjusting its variable arguments; otherwise, they could call
890** a line/count hook before the call hook. Functions coming from
891** an yield already called 'luaD_hookcall' before yielding.)
892*/
893int luaG_tracecall (lua_State *L) {
894 CallInfo *ci = L->ci;
895 Proto *p = ci_func(ci)->p;
896 ci->u.l.trap = 1; /* ensure hooks will be checked */
897 if (ci->u.l.savedpc == p->code) { /* first instruction (not resuming)? */
898 if (p->is_vararg)
899 return 0; /* hooks will start at VARARGPREP instruction */
900 else if (!(ci->callstatus & CIST_HOOKYIELD)) /* not yieded? */
901 luaD_hookcall(L, ci); /* check 'call' hook */
902 }
903 return 1; /* keep 'trap' on */
904}
905
906
907/*
908** Traces the execution of a Lua function. Called before the execution
909** of each opcode, when debug is on. 'L->oldpc' stores the last
910** instruction traced, to detect line changes. When entering a new
911** function, 'npci' will be zero and will test as a new line whatever
912** the value of 'oldpc'. Some exceptional conditions may return to
913** a function without setting 'oldpc'. In that case, 'oldpc' may be
914** invalid; if so, use zero as a valid value. (A wrong but valid 'oldpc'
915** at most causes an extra call to a line hook.)
916** This function is not "Protected" when called, so it should correct
917** 'L->top.p' before calling anything that can run the GC.
918*/
919int luaG_traceexec (lua_State *L, const Instruction *pc) {
920 CallInfo *ci = L->ci;
921 lu_byte mask = L->hookmask;
922 const Proto *p = ci_func(ci)->p;
923 int counthook;
924 if (!(mask & (LUA_MASKLINE | LUA_MASKCOUNT))) { /* no hooks? */
925 ci->u.l.trap = 0; /* don't need to stop again */
926 return 0; /* turn off 'trap' */
927 }
928 pc++; /* reference is always next instruction */
929 ci->u.l.savedpc = pc; /* save 'pc' */
930 counthook = (mask & LUA_MASKCOUNT) && (--L->hookcount == 0);
931 if (counthook)
932 resethookcount(L); /* reset count */
933 else if (!(mask & LUA_MASKLINE))
934 return 1; /* no line hook and count != 0; nothing to be done now */
935 if (ci->callstatus & CIST_HOOKYIELD) { /* hook yielded last time? */
936 ci->callstatus &= ~CIST_HOOKYIELD; /* erase mark */
937 return 1; /* do not call hook again (VM yielded, so it did not move) */
938 }
939 if (!isIT(*(ci->u.l.savedpc - 1))) /* top not being used? */
940 L->top.p = ci->top.p; /* correct top */
941 if (counthook)
942 luaD_hook(L, LUA_HOOKCOUNT, -1, 0, 0); /* call count hook */
943 if (mask & LUA_MASKLINE) {
944 /* 'L->oldpc' may be invalid; use zero in this case */
945 int oldpc = (L->oldpc < p->sizecode) ? L->oldpc : 0;
946 int npci = pcRel(pc, p);
947 if (npci <= oldpc || /* call hook when jump back (loop), */
948 changedline(p, oldpc, npci)) { /* or when enter new line */
949 int newline = luaG_getfuncline(p, npci);
950 luaD_hook(L, LUA_HOOKLINE, newline, 0, 0); /* call line hook */
951 }
952 L->oldpc = npci; /* 'pc' of last call to line hook */
953 }
954 if (L->status == LUA_YIELD) { /* did hook yield? */
955 if (counthook)
956 L->hookcount = 1; /* undo decrement to zero */
957 ci->callstatus |= CIST_HOOKYIELD; /* mark that it yielded */
958 luaD_throw(L, LUA_YIELD);
959 }
960 return 1; /* keep 'trap' on */
961}
962