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