2 ** $Id: ldo.c,v 2.108.1.3 2013/11/08 18:22:50 roberto Exp $
3 ** Stack and Call structure of Lua
4 ** See Copyright Notice in lua.h
8 #include <sys/zfs_context.h>
36 ** {======================================================
37 ** Error-recovery functions
38 ** =======================================================
42 ** LUAI_THROW/LUAI_TRY define how Lua does exception handling. By
43 ** default, Lua handles errors with exceptions when compiling as
44 ** C++ code, with _longjmp/_setjmp when asked to use them, and with
45 ** longjmp/setjmp otherwise.
47 #if !defined(LUAI_THROW)
51 #define LUAI_THROW(L,c) longjmp(&(c)->b)
52 #define LUAI_TRY(L,c,a) if (setjmp(&(c)->b) == 0) { a }
53 #define luai_jmpbuf label_t
55 #define LUAI_THROW(L,c) longjmp((c)->b, 1)
56 #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a }
57 #define luai_jmpbuf jmp_buf
60 #if defined(__cplusplus) && !defined(LUA_USE_LONGJMP)
62 #define LUAI_THROW(L,c) throw(c)
63 #define LUAI_TRY(L,c,a) \
64 try { a } catch(...) { if ((c)->status == 0) (c)->status = -1; }
65 #define luai_jmpbuf int /* dummy variable */
67 #elif defined(LUA_USE_ULONGJMP)
68 /* in Unix, try _longjmp/_setjmp (more efficient) */
69 #define LUAI_THROW(L,c) _longjmp((c)->b, 1)
70 #define LUAI_TRY(L,c,a) if (_setjmp((c)->b) == 0) { a }
71 #define luai_jmpbuf jmp_buf
74 /* default handling with long jumps */
75 #define LUAI_THROW(L,c) longjmp((c)->b, 1)
76 #define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a }
77 #define luai_jmpbuf jmp_buf
86 /* chain list of long jump buffers */
88 struct lua_longjmp *previous;
90 volatile int status; /* error code */
94 static void seterrorobj (lua_State *L, int errcode, StkId oldtop) {
96 case LUA_ERRMEM: { /* memory error? */
97 setsvalue2s(L, oldtop, G(L)->memerrmsg); /* reuse preregistered msg. */
101 setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling"));
105 setobjs2s(L, oldtop, L->top - 1); /* error message on current top */
113 l_noret luaD_throw (lua_State *L, int errcode) {
114 if (L->errorJmp) { /* thread has an error handler? */
115 L->errorJmp->status = errcode; /* set status */
116 LUAI_THROW(L, L->errorJmp); /* jump to it */
118 else { /* thread has no error handler */
119 L->status = cast_byte(errcode); /* mark it as dead */
120 if (G(L)->mainthread->errorJmp) { /* main thread has a handler? */
121 setobjs2s(L, G(L)->mainthread->top++, L->top - 1); /* copy error obj. */
122 luaD_throw(G(L)->mainthread, errcode); /* re-throw in main thread */
124 else { /* no handler at all; abort */
125 if (G(L)->panic) { /* panic function? */
127 G(L)->panic(L); /* call it (last chance to jump out) */
129 panic("no error handler");
135 int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) {
136 unsigned short oldnCcalls = L->nCcalls;
137 struct lua_longjmp lj;
139 lj.previous = L->errorJmp; /* chain new error handler */
144 L->errorJmp = lj.previous; /* restore old error handler */
145 L->nCcalls = oldnCcalls;
149 /* }====================================================== */
152 static void correctstack (lua_State *L, TValue *oldstack) {
155 L->top = (L->top - oldstack) + L->stack;
156 for (up = L->openupval; up != NULL; up = up->gch.next)
157 gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack;
158 for (ci = L->ci; ci != NULL; ci = ci->previous) {
159 ci->top = (ci->top - oldstack) + L->stack;
160 ci->func = (ci->func - oldstack) + L->stack;
162 ci->u.l.base = (ci->u.l.base - oldstack) + L->stack;
167 /* some space for error handling */
168 #define ERRORSTACKSIZE (LUAI_MAXSTACK + 200)
171 void luaD_reallocstack (lua_State *L, int newsize) {
172 TValue *oldstack = L->stack;
173 int lim = L->stacksize;
174 lua_assert(newsize <= LUAI_MAXSTACK || newsize == ERRORSTACKSIZE);
175 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK);
176 luaM_reallocvector(L, L->stack, L->stacksize, newsize, TValue);
177 for (; lim < newsize; lim++)
178 setnilvalue(L->stack + lim); /* erase new segment */
179 L->stacksize = newsize;
180 L->stack_last = L->stack + newsize - EXTRA_STACK;
181 correctstack(L, oldstack);
185 void luaD_growstack (lua_State *L, int n) {
186 int size = L->stacksize;
187 if (size > LUAI_MAXSTACK) /* error after extra size? */
188 luaD_throw(L, LUA_ERRERR);
190 int needed = cast_int(L->top - L->stack) + n + EXTRA_STACK;
191 int newsize = 2 * size;
192 if (newsize > LUAI_MAXSTACK) newsize = LUAI_MAXSTACK;
193 if (newsize < needed) newsize = needed;
194 if (newsize > LUAI_MAXSTACK) { /* stack overflow? */
195 luaD_reallocstack(L, ERRORSTACKSIZE);
196 luaG_runerror(L, "stack overflow");
199 luaD_reallocstack(L, newsize);
204 static int stackinuse (lua_State *L) {
207 for (ci = L->ci; ci != NULL; ci = ci->previous) {
208 lua_assert(ci->top <= L->stack_last);
209 if (lim < ci->top) lim = ci->top;
211 return cast_int(lim - L->stack) + 1; /* part of stack in use */
215 void luaD_shrinkstack (lua_State *L) {
216 int inuse = stackinuse(L);
217 int goodsize = inuse + (inuse / 8) + 2*EXTRA_STACK;
218 if (goodsize > LUAI_MAXSTACK) goodsize = LUAI_MAXSTACK;
219 if (inuse > LUAI_MAXSTACK || /* handling stack overflow? */
220 goodsize >= L->stacksize) /* would grow instead of shrink? */
221 condmovestack(L); /* don't change stack (change only for debugging) */
223 luaD_reallocstack(L, goodsize); /* shrink it */
227 void luaD_hook (lua_State *L, int event, int line) {
228 lua_Hook hook = L->hook;
229 if (hook && L->allowhook) {
230 CallInfo *ci = L->ci;
231 ptrdiff_t top = savestack(L, L->top);
232 ptrdiff_t ci_top = savestack(L, ci->top);
235 ar.currentline = line;
237 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
238 ci->top = L->top + LUA_MINSTACK;
239 lua_assert(ci->top <= L->stack_last);
240 L->allowhook = 0; /* cannot call hooks inside a hook */
241 ci->callstatus |= CIST_HOOKED;
245 lua_assert(!L->allowhook);
247 ci->top = restorestack(L, ci_top);
248 L->top = restorestack(L, top);
249 ci->callstatus &= ~CIST_HOOKED;
254 static void callhook (lua_State *L, CallInfo *ci) {
255 int hook = LUA_HOOKCALL;
256 ci->u.l.savedpc++; /* hooks assume 'pc' is already incremented */
257 if (isLua(ci->previous) &&
258 GET_OPCODE(*(ci->previous->u.l.savedpc - 1)) == OP_TAILCALL) {
259 ci->callstatus |= CIST_TAIL;
260 hook = LUA_HOOKTAILCALL;
262 luaD_hook(L, hook, -1);
263 ci->u.l.savedpc--; /* correct 'pc' */
267 static StkId adjust_varargs (lua_State *L, Proto *p, int actual) {
269 int nfixargs = p->numparams;
271 lua_assert(actual >= nfixargs);
272 /* move fixed parameters to final position */
273 luaD_checkstack(L, p->maxstacksize); /* check again for new 'base' */
274 fixed = L->top - actual; /* first fixed argument */
275 base = L->top; /* final position of first argument */
276 for (i=0; i<nfixargs; i++) {
277 setobjs2s(L, L->top++, fixed + i);
278 setnilvalue(fixed + i);
284 static StkId tryfuncTM (lua_State *L, StkId func) {
285 const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL);
287 ptrdiff_t funcr = savestack(L, func);
288 if (!ttisfunction(tm))
289 luaG_typeerror(L, func, "call");
290 /* Open a hole inside the stack at `func' */
291 for (p = L->top; p > func; p--) setobjs2s(L, p, p-1);
293 func = restorestack(L, funcr); /* previous call may change stack */
294 setobj2s(L, func, tm); /* tag method is the new function to be called */
300 #define next_ci(L) (L->ci = (L->ci->next ? L->ci->next : luaE_extendCI(L)))
304 ** returns true if function has been executed (C function)
306 int luaD_precall (lua_State *L, StkId func, int nresults) {
309 int n; /* number of arguments (Lua) or returns (C) */
310 ptrdiff_t funcr = savestack(L, func);
311 switch (ttype(func)) {
312 case LUA_TLCF: /* light C function */
315 case LUA_TCCL: { /* C closure */
316 f = clCvalue(func)->f;
318 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */
319 ci = next_ci(L); /* now 'enter' new function */
320 ci->nresults = nresults;
321 ci->func = restorestack(L, funcr);
322 ci->top = L->top + LUA_MINSTACK;
323 lua_assert(ci->top <= L->stack_last);
325 luaC_checkGC(L); /* stack grow uses memory */
326 if (L->hookmask & LUA_MASKCALL)
327 luaD_hook(L, LUA_HOOKCALL, -1);
329 n = (*f)(L); /* do the actual call */
331 api_checknelems(L, n);
332 luaD_poscall(L, L->top - n);
335 case LUA_TLCL: { /* Lua function: prepare its call */
337 Proto *p = clLvalue(func)->p;
338 n = cast_int(L->top - func) - 1; /* number of real arguments */
339 luaD_checkstack(L, p->maxstacksize);
340 for (; n < p->numparams; n++)
341 setnilvalue(L->top++); /* complete missing arguments */
343 func = restorestack(L, funcr);
347 base = adjust_varargs(L, p, n);
348 func = restorestack(L, funcr); /* previous call can change stack */
350 ci = next_ci(L); /* now 'enter' new function */
351 ci->nresults = nresults;
354 ci->top = base + p->maxstacksize;
355 lua_assert(ci->top <= L->stack_last);
356 ci->u.l.savedpc = p->code; /* starting point */
357 ci->callstatus = CIST_LUA;
359 luaC_checkGC(L); /* stack grow uses memory */
360 if (L->hookmask & LUA_MASKCALL)
364 default: { /* not a function */
365 func = tryfuncTM(L, func); /* retry with 'function' tag method */
366 return luaD_precall(L, func, nresults); /* now it must be a function */
372 int luaD_poscall (lua_State *L, StkId firstResult) {
375 CallInfo *ci = L->ci;
376 if (L->hookmask & (LUA_MASKRET | LUA_MASKLINE)) {
377 if (L->hookmask & LUA_MASKRET) {
378 ptrdiff_t fr = savestack(L, firstResult); /* hook may change stack */
379 luaD_hook(L, LUA_HOOKRET, -1);
380 firstResult = restorestack(L, fr);
382 L->oldpc = ci->previous->u.l.savedpc; /* 'oldpc' for caller function */
384 res = ci->func; /* res == final position of 1st result */
385 wanted = ci->nresults;
386 L->ci = ci = ci->previous; /* back to caller */
387 /* move results to correct place */
388 for (i = wanted; i != 0 && firstResult < L->top; i--)
389 setobjs2s(L, res++, firstResult++);
393 return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */
398 ** Call a function (C or Lua). The function to be called is at *func.
399 ** The arguments are on the stack, right after the function.
400 ** When returns, all the results are on the stack, starting at the original
401 ** function position.
403 void luaD_call (lua_State *L, StkId func, int nResults, int allowyield) {
404 if (++L->nCcalls >= LUAI_MAXCCALLS) {
405 if (L->nCcalls == LUAI_MAXCCALLS)
406 luaG_runerror(L, "C stack overflow");
407 else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3)))
408 luaD_throw(L, LUA_ERRERR); /* error while handing stack error */
410 if (!allowyield) L->nny++;
411 if (!luaD_precall(L, func, nResults)) /* is a Lua function? */
412 luaV_execute(L); /* call it */
413 if (!allowyield) L->nny--;
418 static void finishCcall (lua_State *L) {
419 CallInfo *ci = L->ci;
421 lua_assert(ci->u.c.k != NULL); /* must have a continuation */
422 lua_assert(L->nny == 0);
423 if (ci->callstatus & CIST_YPCALL) { /* was inside a pcall? */
424 ci->callstatus &= ~CIST_YPCALL; /* finish 'lua_pcall' */
425 L->errfunc = ci->u.c.old_errfunc;
427 /* finish 'lua_callk'/'lua_pcall' */
428 adjustresults(L, ci->nresults);
429 /* call continuation function */
430 if (!(ci->callstatus & CIST_STAT)) /* no call status? */
431 ci->u.c.status = LUA_YIELD; /* 'default' status */
432 lua_assert(ci->u.c.status != LUA_OK);
433 ci->callstatus = (ci->callstatus & ~(CIST_YPCALL | CIST_STAT)) | CIST_YIELDED;
437 api_checknelems(L, n);
438 /* finish 'luaD_precall' */
439 luaD_poscall(L, L->top - n);
443 static void unroll (lua_State *L, void *ud) {
446 if (L->ci == &L->base_ci) /* stack is empty? */
447 return; /* coroutine finished normally */
448 if (!isLua(L->ci)) /* C function? */
450 else { /* Lua function */
451 luaV_finishOp(L); /* finish interrupted instruction */
452 luaV_execute(L); /* execute down to higher C 'boundary' */
459 ** check whether thread has a suspended protected call
461 static CallInfo *findpcall (lua_State *L) {
463 for (ci = L->ci; ci != NULL; ci = ci->previous) { /* search for a pcall */
464 if (ci->callstatus & CIST_YPCALL)
467 return NULL; /* no pending pcall */
471 static int recover (lua_State *L, int status) {
473 CallInfo *ci = findpcall(L);
474 if (ci == NULL) return 0; /* no recovery point */
475 /* "finish" luaD_pcall */
476 oldtop = restorestack(L, ci->extra);
477 luaF_close(L, oldtop);
478 seterrorobj(L, status, oldtop);
480 L->allowhook = ci->u.c.old_allowhook;
481 L->nny = 0; /* should be zero to be yieldable */
483 L->errfunc = ci->u.c.old_errfunc;
484 ci->callstatus |= CIST_STAT; /* call has error status */
485 ci->u.c.status = status; /* (here it is) */
486 return 1; /* continue running the coroutine */
491 ** signal an error in the call to 'resume', not in the execution of the
492 ** coroutine itself. (Such errors should not be handled by any coroutine
493 ** error handler and should not kill the coroutine.)
495 static l_noret resume_error (lua_State *L, const char *msg, StkId firstArg) {
496 L->top = firstArg; /* remove args from the stack */
497 setsvalue2s(L, L->top, luaS_new(L, msg)); /* push error message */
499 luaD_throw(L, -1); /* jump back to 'lua_resume' */
504 ** do the work for 'lua_resume' in protected mode
506 static void resume_cb (lua_State *L, void *ud) {
507 int nCcalls = L->nCcalls;
508 StkId firstArg = cast(StkId, ud);
509 CallInfo *ci = L->ci;
510 if (nCcalls >= LUAI_MAXCCALLS)
511 resume_error(L, "C stack overflow", firstArg);
512 if (L->status == LUA_OK) { /* may be starting a coroutine */
513 if (ci != &L->base_ci) /* not in base level? */
514 resume_error(L, "cannot resume non-suspended coroutine", firstArg);
515 /* coroutine is in base level; start running it */
516 if (!luaD_precall(L, firstArg - 1, LUA_MULTRET)) /* Lua function? */
517 luaV_execute(L); /* call it */
519 else if (L->status != LUA_YIELD)
520 resume_error(L, "cannot resume dead coroutine", firstArg);
521 else { /* resuming from previous yield */
523 ci->func = restorestack(L, ci->extra);
524 if (isLua(ci)) /* yielded inside a hook? */
525 luaV_execute(L); /* just continue running Lua code */
526 else { /* 'common' yield */
527 if (ci->u.c.k != NULL) { /* does it have a continuation? */
529 ci->u.c.status = LUA_YIELD; /* 'default' status */
530 ci->callstatus |= CIST_YIELDED;
532 n = (*ci->u.c.k)(L); /* call continuation */
534 api_checknelems(L, n);
535 firstArg = L->top - n; /* yield results come from continuation */
537 luaD_poscall(L, firstArg); /* finish 'luaD_precall' */
541 lua_assert(nCcalls == L->nCcalls);
545 LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) {
547 int oldnny = L->nny; /* save 'nny' */
549 luai_userstateresume(L, nargs);
550 L->nCcalls = (from) ? from->nCcalls + 1 : 1;
551 L->nny = 0; /* allow yields */
552 api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
553 status = luaD_rawrunprotected(L, resume_cb, L->top - nargs);
554 if (status == -1) /* error calling 'lua_resume'? */
556 else { /* yield or regular error */
557 while (status != LUA_OK && status != LUA_YIELD) { /* error? */
558 if (recover(L, status)) /* recover point? */
559 status = luaD_rawrunprotected(L, unroll, NULL); /* run continuation */
560 else { /* unrecoverable error */
561 L->status = cast_byte(status); /* mark thread as `dead' */
562 seterrorobj(L, status, L->top);
567 lua_assert(status == L->status);
569 L->nny = oldnny; /* restore 'nny' */
571 lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
577 LUA_API int lua_yieldk (lua_State *L, int nresults, int ctx, lua_CFunction k) {
578 CallInfo *ci = L->ci;
579 luai_userstateyield(L, nresults);
581 api_checknelems(L, nresults);
583 if (L != G(L)->mainthread)
584 luaG_runerror(L, "attempt to yield across a C-call boundary");
586 luaG_runerror(L, "attempt to yield from outside a coroutine");
588 L->status = LUA_YIELD;
589 ci->extra = savestack(L, ci->func); /* save current 'func' */
590 if (isLua(ci)) { /* inside a hook? */
591 api_check(L, k == NULL, "hooks cannot continue after yielding");
594 if ((ci->u.c.k = k) != NULL) /* is there a continuation? */
595 ci->u.c.ctx = ctx; /* save context */
596 ci->func = L->top - nresults - 1; /* protect stack below results */
597 luaD_throw(L, LUA_YIELD);
599 lua_assert(ci->callstatus & CIST_HOOKED); /* must be inside a hook */
601 return 0; /* return to 'luaD_hook' */
605 int luaD_pcall (lua_State *L, Pfunc func, void *u,
606 ptrdiff_t old_top, ptrdiff_t ef) {
608 CallInfo *old_ci = L->ci;
609 lu_byte old_allowhooks = L->allowhook;
610 unsigned short old_nny = L->nny;
611 ptrdiff_t old_errfunc = L->errfunc;
613 status = luaD_rawrunprotected(L, func, u);
614 if (status != LUA_OK) { /* an error occurred? */
615 StkId oldtop = restorestack(L, old_top);
616 luaF_close(L, oldtop); /* close possible pending closures */
617 seterrorobj(L, status, oldtop);
619 L->allowhook = old_allowhooks;
623 L->errfunc = old_errfunc;
630 ** Execute a protected parser.
632 struct SParser { /* data to `f_parser' */
634 Mbuffer buff; /* dynamic structure used by the scanner */
635 Dyndata dyd; /* dynamic structures used by the parser */
641 static void checkmode (lua_State *L, const char *mode, const char *x) {
642 if (mode && strchr(mode, x[0]) == NULL) {
644 "attempt to load a %s chunk (mode is " LUA_QS ")", x, mode);
645 luaD_throw(L, LUA_ERRSYNTAX);
650 static void f_parser (lua_State *L, void *ud) {
653 struct SParser *p = cast(struct SParser *, ud);
654 int c = zgetc(p->z); /* read first character */
655 if (c == LUA_SIGNATURE[0]) {
656 checkmode(L, p->mode, "binary");
657 cl = luaU_undump(L, p->z, &p->buff, p->name);
660 checkmode(L, p->mode, "text");
661 cl = luaY_parser(L, p->z, &p->buff, &p->dyd, p->name, c);
663 lua_assert(cl->l.nupvalues == cl->l.p->sizeupvalues);
664 for (i = 0; i < cl->l.nupvalues; i++) { /* initialize upvalues */
665 UpVal *up = luaF_newupval(L);
666 cl->l.upvals[i] = up;
667 luaC_objbarrier(L, cl, up);
672 int luaD_protectedparser (lua_State *L, ZIO *z, const char *name,
676 L->nny++; /* cannot yield during parsing */
677 p.z = z; p.name = name; p.mode = mode;
678 p.dyd.actvar.arr = NULL; p.dyd.actvar.size = 0;
679 p.dyd.gt.arr = NULL; p.dyd.gt.size = 0;
680 p.dyd.label.arr = NULL; p.dyd.label.size = 0;
681 luaZ_initbuffer(L, &p.buff);
682 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc);
683 luaZ_freebuffer(L, &p.buff);
684 luaM_freearray(L, p.dyd.actvar.arr, p.dyd.actvar.size);
685 luaM_freearray(L, p.dyd.gt.arr, p.dyd.gt.size);
686 luaM_freearray(L, p.dyd.label.arr, p.dyd.label.size);