/src/middleware/lua/ldo.c
C | 518 lines | 424 code | 67 blank | 27 comment | 83 complexity | 6ac8b3237c6186ca13f786e546545868 MD5 | raw file
1/* 2** $Id: ldo.c,v 2.38.1.3 2008/01/18 22:31:22 roberto Exp $ 3** Stack and Call structure of Lua 4** See Copyright Notice in lua.h 5*/ 6 7 8#include <setjmp.h> 9#include <stdlib.h> 10#include <string.h> 11 12#define ldo_c 13#define LUA_CORE 14 15#include "lua.h" 16 17#include "ldebug.h" 18#include "ldo.h" 19#include "lfunc.h" 20#include "lgc.h" 21#include "lmem.h" 22#include "lobject.h" 23#include "lopcodes.h" 24#include "lparser.h" 25#include "lstate.h" 26#include "lstring.h" 27#include "ltable.h" 28#include "ltm.h" 29#include "lundump.h" 30#include "lvm.h" 31#include "lzio.h" 32 33 34 35 36/* 37** {====================================================== 38** Error-recovery functions 39** ======================================================= 40*/ 41 42 43/* chain list of long jump buffers */ 44struct lua_longjmp { 45 struct lua_longjmp *previous; 46 luai_jmpbuf b; 47 volatile int status; /* error code */ 48}; 49 50 51void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) { 52 switch (errcode) { 53 case LUA_ERRMEM: { 54 setsvalue2s(L, oldtop, luaS_newliteral(L, MEMERRMSG)); 55 break; 56 } 57 case LUA_ERRERR: { 58 setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); 59 break; 60 } 61 case LUA_ERRSYNTAX: 62 case LUA_ERRRUN: { 63 setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ 64 break; 65 } 66 } 67 L->top = oldtop + 1; 68} 69 70 71static void restore_stack_limit (lua_State *L) { 72 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1); 73 if (L->size_ci > LUAI_MAXCALLS) { /* there was an overflow? */ 74 int inuse = cast_int(L->ci - L->base_ci); 75 if (inuse + 1 < LUAI_MAXCALLS) /* can `undo' overflow? */ 76 luaD_reallocCI(L, LUAI_MAXCALLS); 77 } 78} 79 80 81static void resetstack (lua_State *L, int status) { 82 L->ci = L->base_ci; 83 L->base = L->ci->base; 84 luaF_close(L, L->base); /* close eventual pending closures */ 85 luaD_seterrorobj(L, status, L->base); 86 L->nCcalls = L->baseCcalls; 87 L->allowhook = 1; 88 restore_stack_limit(L); 89 L->errfunc = 0; 90 L->errorJmp = NULL; 91} 92 93 94void luaD_throw (lua_State *L, int errcode) { 95 if (L->errorJmp) { 96 L->errorJmp->status = errcode; 97 LUAI_THROW(L, L->errorJmp); 98 } 99 else { 100 L->status = cast_byte(errcode); 101 if (G(L)->panic) { 102 resetstack(L, errcode); 103 lua_unlock(L); 104 G(L)->panic(L); 105 } 106 exit(EXIT_FAILURE); 107 } 108} 109 110 111int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { 112 struct lua_longjmp lj; 113 lj.status = 0; 114 lj.previous = L->errorJmp; /* chain new error handler */ 115 L->errorJmp = &lj; 116 LUAI_TRY(L, &lj, 117 (*f)(L, ud); 118 ); 119 L->errorJmp = lj.previous; /* restore old error handler */ 120 return lj.status; 121} 122 123/* }====================================================== */ 124 125 126static void correctstack (lua_State *L, TValue *oldstack) { 127 CallInfo *ci; 128 GCObject *up; 129 L->top = (L->top - oldstack) + L->stack; 130 for (up = L->openupval; up != NULL; up = up->gch.next) 131 gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack; 132 for (ci = L->base_ci; ci <= L->ci; ci++) { 133 ci->top = (ci->top - oldstack) + L->stack; 134 ci->base = (ci->base - oldstack) + L->stack; 135 ci->func = (ci->func - oldstack) + L->stack; 136 } 137 L->base = (L->base - oldstack) + L->stack; 138} 139 140 141void luaD_reallocstack (lua_State *L, int newsize) { 142 TValue *oldstack = L->stack; 143 int realsize = newsize + 1 + EXTRA_STACK; 144 lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1); 145 luaM_reallocvector(L, L->stack, L->stacksize, realsize, TValue); 146 L->stacksize = realsize; 147 L->stack_last = L->stack+newsize; 148 correctstack(L, oldstack); 149} 150 151 152void luaD_reallocCI (lua_State *L, int newsize) { 153 CallInfo *oldci = L->base_ci; 154 luaM_reallocvector(L, L->base_ci, L->size_ci, newsize, CallInfo); 155 L->size_ci = newsize; 156 L->ci = (L->ci - oldci) + L->base_ci; 157 L->end_ci = L->base_ci + L->size_ci - 1; 158} 159 160 161void luaD_growstack (lua_State *L, int n) { 162 if (n <= L->stacksize) /* double size is enough? */ 163 luaD_reallocstack(L, 2*L->stacksize); 164 else 165 luaD_reallocstack(L, L->stacksize + n); 166} 167 168 169static CallInfo *growCI (lua_State *L) { 170 if (L->size_ci > LUAI_MAXCALLS) /* overflow while handling overflow? */ 171 luaD_throw(L, LUA_ERRERR); 172 else { 173 luaD_reallocCI(L, 2*L->size_ci); 174 if (L->size_ci > LUAI_MAXCALLS) 175 luaG_runerror(L, "stack overflow"); 176 } 177 return ++L->ci; 178} 179 180 181void luaD_callhook (lua_State *L, int event, int line) { 182 lua_Hook hook = L->hook; 183 if (hook && L->allowhook) { 184 ptrdiff_t top = savestack(L, L->top); 185 ptrdiff_t ci_top = savestack(L, L->ci->top); 186 lua_Debug ar; 187 ar.event = event; 188 ar.currentline = line; 189 if (event == LUA_HOOKTAILRET) 190 ar.i_ci = 0; /* tail call; no debug information about it */ 191 else 192 ar.i_ci = cast_int(L->ci - L->base_ci); 193 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 194 L->ci->top = L->top + LUA_MINSTACK; 195 lua_assert(L->ci->top <= L->stack_last); 196 L->allowhook = 0; /* cannot call hooks inside a hook */ 197 lua_unlock(L); 198 (*hook)(L, &ar); 199 lua_lock(L); 200 lua_assert(!L->allowhook); 201 L->allowhook = 1; 202 L->ci->top = restorestack(L, ci_top); 203 L->top = restorestack(L, top); 204 } 205} 206 207 208static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { 209 int i; 210 int nfixargs = p->numparams; 211 Table *htab = NULL; 212 StkId base, fixed; 213 for (; actual < nfixargs; ++actual) 214 setnilvalue(L->top++); 215#if defined(LUA_COMPAT_VARARG) 216 if (p->is_vararg & VARARG_NEEDSARG) { /* compat. with old-style vararg? */ 217 int nvar = actual - nfixargs; /* number of extra arguments */ 218 lua_assert(p->is_vararg & VARARG_HASARG); 219 luaC_checkGC(L); 220 htab = luaH_new(L, nvar, 1); /* create `arg' table */ 221 for (i=0; i<nvar; i++) /* put extra arguments into `arg' table */ 222 setobj2n(L, luaH_setnum(L, htab, i+1), L->top - nvar + i); 223 /* store counter in field `n' */ 224 setnvalue(luaH_setstr(L, htab, luaS_newliteral(L, "n")), cast_num(nvar)); 225 } 226#endif 227 /* move fixed parameters to final position */ 228 fixed = L->top - actual; /* first fixed argument */ 229 base = L->top; /* final position of first argument */ 230 for (i=0; i<nfixargs; i++) { 231 setobjs2s(L, L->top++, fixed+i); 232 setnilvalue(fixed+i); 233 } 234 /* add `arg' parameter */ 235 if (htab) { 236 sethvalue(L, L->top++, htab); 237 lua_assert(iswhite(obj2gco(htab))); 238 } 239 return base; 240} 241 242 243static StkId tryfuncTM (lua_State *L, StkId func) { 244 const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); 245 StkId p; 246 ptrdiff_t funcr = savestack(L, func); 247 if (!ttisfunction(tm)) 248 luaG_typeerror(L, func, "call"); 249 /* Open a hole inside the stack at `func' */ 250 for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); 251 incr_top(L); 252 func = restorestack(L, funcr); /* previous call may change stack */ 253 setobj2s(L, func, tm); /* tag method is the new function to be called */ 254 return func; 255} 256 257 258 259#define inc_ci(L) \ 260 ((L->ci == L->end_ci) ? growCI(L) : \ 261 (condhardstacktests(luaD_reallocCI(L, L->size_ci)), ++L->ci)) 262 263 264int luaD_precall (lua_State *L, StkId func, int nresults) { 265 LClosure *cl; 266 ptrdiff_t funcr; 267 if (!ttisfunction(func)) /* `func' is not a function? */ 268 func = tryfuncTM(L, func); /* check the `function' tag method */ 269 funcr = savestack(L, func); 270 cl = &clvalue(func)->l; 271 L->ci->savedpc = L->savedpc; 272 if (!cl->isC) { /* Lua function? prepare its call */ 273 CallInfo *ci; 274 StkId st, base; 275 Proto *p = cl->p; 276 luaD_checkstack(L, p->maxstacksize); 277 func = restorestack(L, funcr); 278 if (!p->is_vararg) { /* no varargs? */ 279 base = func + 1; 280 if (L->top > base + p->numparams) 281 L->top = base + p->numparams; 282 } 283 else { /* vararg function */ 284 int nargs = cast_int(L->top - func) - 1; 285 base = adjust_varargs(L, p, nargs); 286 func = restorestack(L, funcr); /* previous call may change the stack */ 287 } 288 ci = inc_ci(L); /* now `enter' new function */ 289 ci->func = func; 290 L->base = ci->base = base; 291 ci->top = L->base + p->maxstacksize; 292 lua_assert(ci->top <= L->stack_last); 293 L->savedpc = p->code; /* starting point */ 294 ci->tailcalls = 0; 295 ci->nresults = nresults; 296 for (st = L->top; st < ci->top; st++) 297 setnilvalue(st); 298 L->top = ci->top; 299 if (L->hookmask & LUA_MASKCALL) { 300 L->savedpc++; /* hooks assume 'pc' is already incremented */ 301 luaD_callhook(L, LUA_HOOKCALL, -1); 302 L->savedpc--; /* correct 'pc' */ 303 } 304 return PCRLUA; 305 } 306 else { /* if is a C function, call it */ 307 CallInfo *ci; 308 int n; 309 luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ 310 ci = inc_ci(L); /* now `enter' new function */ 311 ci->func = restorestack(L, funcr); 312 L->base = ci->base = ci->func + 1; 313 ci->top = L->top + LUA_MINSTACK; 314 lua_assert(ci->top <= L->stack_last); 315 ci->nresults = nresults; 316 if (L->hookmask & LUA_MASKCALL) 317 luaD_callhook(L, LUA_HOOKCALL, -1); 318 lua_unlock(L); 319 n = (*curr_func(L)->c.f)(L); /* do the actual call */ 320 lua_lock(L); 321 if (n < 0) /* yielding? */ 322 return PCRYIELD; 323 else { 324 luaD_poscall(L, L->top - n); 325 return PCRC; 326 } 327 } 328} 329 330 331static StkId callrethooks (lua_State *L, StkId firstResult) { 332 ptrdiff_t fr = savestack(L, firstResult); /* next call may change stack */ 333 luaD_callhook(L, LUA_HOOKRET, -1); 334 if (f_isLua(L->ci)) { /* Lua function? */ 335 while ((L->hookmask & LUA_MASKRET) && L->ci->tailcalls--) /* tail calls */ 336 luaD_callhook(L, LUA_HOOKTAILRET, -1); 337 } 338 return restorestack(L, fr); 339} 340 341 342int luaD_poscall (lua_State *L, StkId firstResult) { 343 StkId res; 344 int wanted, i; 345 CallInfo *ci; 346 if (L->hookmask & LUA_MASKRET) 347 firstResult = callrethooks(L, firstResult); 348 ci = L->ci--; 349 res = ci->func; /* res == final position of 1st result */ 350 wanted = ci->nresults; 351 L->base = (ci - 1)->base; /* restore base */ 352 L->savedpc = (ci - 1)->savedpc; /* restore savedpc */ 353 /* move results to correct place */ 354 for (i = wanted; i != 0 && firstResult < L->top; i--) 355 setobjs2s(L, res++, firstResult++); 356 while (i-- > 0) 357 setnilvalue(res++); 358 L->top = res; 359 return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */ 360} 361 362 363/* 364** Call a function (C or Lua). The function to be called is at *func. 365** The arguments are on the stack, right after the function. 366** When returns, all the results are on the stack, starting at the original 367** function position. 368*/ 369void luaD_call (lua_State *L, StkId func, int nResults) { 370 if (++L->nCcalls >= LUAI_MAXCCALLS) { 371 if (L->nCcalls == LUAI_MAXCCALLS) 372 luaG_runerror(L, "C stack overflow"); 373 else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) 374 luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ 375 } 376 if (luaD_precall(L, func, nResults) == PCRLUA) /* is a Lua function? */ 377 luaV_execute(L, 1); /* call it */ 378 L->nCcalls--; 379 luaC_checkGC(L); 380} 381 382 383static void resume (lua_State *L, void *ud) { 384 StkId firstArg = cast(StkId, ud); 385 CallInfo *ci = L->ci; 386 if (L->status == 0) { /* start coroutine? */ 387 lua_assert(ci == L->base_ci && firstArg > L->base); 388 if (luaD_precall(L, firstArg - 1, LUA_MULTRET) != PCRLUA) 389 return; 390 } 391 else { /* resuming from previous yield */ 392 lua_assert(L->status == LUA_YIELD); 393 L->status = 0; 394 if (!f_isLua(ci)) { /* `common' yield? */ 395 /* finish interrupted execution of `OP_CALL' */ 396 lua_assert(GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_CALL || 397 GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_TAILCALL); 398 if (luaD_poscall(L, firstArg)) /* complete it... */ 399 L->top = L->ci->top; /* and correct top if not multiple results */ 400 } 401 else /* yielded inside a hook: just continue its execution */ 402 L->base = L->ci->base; 403 } 404 luaV_execute(L, cast_int(L->ci - L->base_ci)); 405} 406 407 408static int resume_error (lua_State *L, const char *msg) { 409 L->top = L->ci->base; 410 setsvalue2s(L, L->top, luaS_new(L, msg)); 411 incr_top(L); 412 lua_unlock(L); 413 return LUA_ERRRUN; 414} 415 416 417LUA_API int lua_resume (lua_State *L, int nargs) { 418 int status; 419 lua_lock(L); 420 if (L->status != LUA_YIELD && (L->status != 0 || L->ci != L->base_ci)) 421 return resume_error(L, "cannot resume non-suspended coroutine"); 422 if (L->nCcalls >= LUAI_MAXCCALLS) 423 return resume_error(L, "C stack overflow"); 424 luai_userstateresume(L, nargs); 425 lua_assert(L->errfunc == 0); 426 L->baseCcalls = ++L->nCcalls; 427 status = luaD_rawrunprotected(L, resume, L->top - nargs); 428 if (status != 0) { /* error? */ 429 L->status = cast_byte(status); /* mark thread as `dead' */ 430 luaD_seterrorobj(L, status, L->top); 431 L->ci->top = L->top; 432 } 433 else { 434 lua_assert(L->nCcalls == L->baseCcalls); 435 status = L->status; 436 } 437 --L->nCcalls; 438 lua_unlock(L); 439 return status; 440} 441 442 443LUA_API int lua_yield (lua_State *L, int nresults) { 444 luai_userstateyield(L, nresults); 445 lua_lock(L); 446 if (L->nCcalls > L->baseCcalls) 447 luaG_runerror(L, "attempt to yield across metamethod/C-call boundary"); 448 L->base = L->top - nresults; /* protect stack slots below */ 449 L->status = LUA_YIELD; 450 lua_unlock(L); 451 return -1; 452} 453 454 455int luaD_pcall (lua_State *L, Pfunc func, void *u, 456 ptrdiff_t old_top, ptrdiff_t ef) { 457 int status; 458 unsigned short oldnCcalls = L->nCcalls; 459 ptrdiff_t old_ci = saveci(L, L->ci); 460 lu_byte old_allowhooks = L->allowhook; 461 ptrdiff_t old_errfunc = L->errfunc; 462 L->errfunc = ef; 463 status = luaD_rawrunprotected(L, func, u); 464 if (status != 0) { /* an error occurred? */ 465 StkId oldtop = restorestack(L, old_top); 466 luaF_close(L, oldtop); /* close eventual pending closures */ 467 luaD_seterrorobj(L, status, oldtop); 468 L->nCcalls = oldnCcalls; 469 L->ci = restoreci(L, old_ci); 470 L->base = L->ci->base; 471 L->savedpc = L->ci->savedpc; 472 L->allowhook = old_allowhooks; 473 restore_stack_limit(L); 474 } 475 L->errfunc = old_errfunc; 476 return status; 477} 478 479 480 481/* 482** Execute a protected parser. 483*/ 484struct SParser { /* data to `f_parser' */ 485 ZIO *z; 486 Mbuffer buff; /* buffer to be used by the scanner */ 487 const char *name; 488}; 489 490static void f_parser (lua_State *L, void *ud) { 491 int i; 492 Proto *tf; 493 Closure *cl; 494 struct SParser *p = cast(struct SParser *, ud); 495 int c = luaZ_lookahead(p->z); 496 luaC_checkGC(L); 497 tf = ((c == LUA_SIGNATURE[0]) ? luaU_undump : luaY_parser)(L, p->z, 498 &p->buff, p->name); 499 cl = luaF_newLclosure(L, tf->nups, hvalue(gt(L))); 500 cl->l.p = tf; 501 for (i = 0; i < tf->nups; i++) /* initialize eventual upvalues */ 502 cl->l.upvals[i] = luaF_newupval(L); 503 setclvalue(L, L->top, cl); 504 incr_top(L); 505} 506 507 508int luaD_protectedparser (lua_State *L, ZIO *z, const char *name) { 509 struct SParser p; 510 int status; 511 p.z = z; p.name = name; 512 luaZ_initbuffer(L, &p.buff); 513 status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); 514 luaZ_freebuffer(L, &p.buff); 515 return status; 516} 517 518