/*** $Id: ldo.c,v 2.38.1.3 2008/01/18 22:31:22 roberto Exp $** Stack and Call structure of Lua** See Copyright Notice in lua.h*/#include <setjmp.h>#include <stdlib.h>#include <string.h>#define ldo_c#define LUA_CORE#include "lua.h"#include "ldebug.h"#include "ldo.h"#include "lfunc.h"#include "lgc.h"#include "lmem.h"#include "lobject.h"#include "lopcodes.h"#include "lparser.h"#include "lstate.h"#include "lstring.h"#include "ltable.h"#include "ltm.h"#include "lundump.h"#include "lvm.h"#include "lzio.h"/*** {======================================================** Error-recovery functions** =======================================================*//* chain list of long jump buffers */struct lua_longjmp { struct lua_longjmp *previous; luai_jmpbuf b; volatile int status; /* error code */};void luaD_seterrorobj (lua_State *L, int errcode, StkId oldtop) { switch (errcode) { case LUA_ERRMEM: { setsvalue2s(L, oldtop, luaS_newliteral(L, MEMERRMSG)); break; } case LUA_ERRERR: { setsvalue2s(L, oldtop, luaS_newliteral(L, "error in error handling")); break; } case LUA_ERRSYNTAX: case LUA_ERRRUN: { setobjs2s(L, oldtop, L->top - 1); /* error message on current top */ break; } } L->top = oldtop + 1;}static void restore_stack_limit (lua_State *L) { lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1); if (L->size_ci > LUAI_MAXCALLS) { /* there was an overflow? */ int inuse = cast_int(L->ci - L->base_ci); if (inuse + 1 < LUAI_MAXCALLS) /* can `undo' overflow? */ luaD_reallocCI(L, LUAI_MAXCALLS); }}static void resetstack (lua_State *L, int status) { L->ci = L->base_ci; L->base = L->ci->base; luaF_close(L, L->base); /* close eventual pending closures */ luaD_seterrorobj(L, status, L->base); L->nCcalls = L->baseCcalls; L->allowhook = 1; restore_stack_limit(L); L->errfunc = 0; L->errorJmp = NULL;}void luaD_throw (lua_State *L, int errcode) { if (L->errorJmp) { L->errorJmp->status = errcode; LUAI_THROW(L, L->errorJmp); } else { L->status = cast_byte(errcode); if (G(L)->panic) { resetstack(L, errcode); lua_unlock(L); G(L)->panic(L); } exit(EXIT_FAILURE); }}int luaD_rawrunprotected (lua_State *L, Pfunc f, void *ud) { struct lua_longjmp lj; lj.status = 0; lj.previous = L->errorJmp; /* chain new error handler */ L->errorJmp = &lj; LUAI_TRY(L, &lj, (*f)(L, ud); ); L->errorJmp = lj.previous; /* restore old error handler */ return lj.status;}/* }====================================================== */static void correctstack (lua_State *L, TValue *oldstack) { CallInfo *ci; GCObject *up; L->top = (L->top - oldstack) + L->stack; for (up = L->openupval; up != NULL; up = up->gch.next) gco2uv(up)->v = (gco2uv(up)->v - oldstack) + L->stack; for (ci = L->base_ci; ci <= L->ci; ci++) { ci->top = (ci->top - oldstack) + L->stack; ci->base = (ci->base - oldstack) + L->stack; ci->func = (ci->func - oldstack) + L->stack; } L->base = (L->base - oldstack) + L->stack;}void luaD_reallocstack (lua_State *L, int newsize) { TValue *oldstack = L->stack; int realsize = newsize + 1 + EXTRA_STACK; lua_assert(L->stack_last - L->stack == L->stacksize - EXTRA_STACK - 1); luaM_reallocvector(L, L->stack, L->stacksize, realsize, TValue); L->stacksize = realsize; L->stack_last = L->stack+newsize; correctstack(L, oldstack);}void luaD_reallocCI (lua_State *L, int newsize) { CallInfo *oldci = L->base_ci; luaM_reallocvector(L, L->base_ci, L->size_ci, newsize, CallInfo); L->size_ci = newsize; L->ci = (L->ci - oldci) + L->base_ci; L->end_ci = L->base_ci + L->size_ci - 1;}void luaD_growstack (lua_State *L, int n) { if (n <= L->stacksize) /* double size is enough? */ luaD_reallocstack(L, 2*L->stacksize); else luaD_reallocstack(L, L->stacksize + n);}static CallInfo *growCI (lua_State *L) { if (L->size_ci > LUAI_MAXCALLS) /* overflow while handling overflow? */ luaD_throw(L, LUA_ERRERR); else { luaD_reallocCI(L, 2*L->size_ci); if (L->size_ci > LUAI_MAXCALLS) luaG_runerror(L, "stack overflow"); } return ++L->ci;}void luaD_callhook (lua_State *L, int event, int line) { lua_Hook hook = L->hook; if (hook && L->allowhook) { ptrdiff_t top = savestack(L, L->top); ptrdiff_t ci_top = savestack(L, L->ci->top); lua_Debug ar; ar.event = event; ar.currentline = line; if (event == LUA_HOOKTAILRET) ar.i_ci = 0; /* tail call; no debug information about it */ else ar.i_ci = cast_int(L->ci - L->base_ci); luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ L->ci->top = L->top + LUA_MINSTACK; lua_assert(L->ci->top <= L->stack_last); L->allowhook = 0; /* cannot call hooks inside a hook */ lua_unlock(L); (*hook)(L, &ar); lua_lock(L); lua_assert(!L->allowhook); L->allowhook = 1; L->ci->top = restorestack(L, ci_top); L->top = restorestack(L, top); }}static StkId adjust_varargs (lua_State *L, Proto *p, int actual) { int i; int nfixargs = p->numparams; Table *htab = NULL; StkId base, fixed; for (; actual < nfixargs; ++actual) setnilvalue(L->top++);#if defined(LUA_COMPAT_VARARG) if (p->is_vararg & VARARG_NEEDSARG) { /* compat. with old-style vararg? */ int nvar = actual - nfixargs; /* number of extra arguments */ lua_assert(p->is_vararg & VARARG_HASARG); luaC_checkGC(L); htab = luaH_new(L, nvar, 1); /* create `arg' table */ for (i=0; i<nvar; i++) /* put extra arguments into `arg' table */ setobj2n(L, luaH_setnum(L, htab, i+1), L->top - nvar + i); /* store counter in field `n' */ setnvalue(luaH_setstr(L, htab, luaS_newliteral(L, "n")), cast_num(nvar)); }#endif /* move fixed parameters to final position */ fixed = L->top - actual; /* first fixed argument */ base = L->top; /* final position of first argument */ for (i=0; i<nfixargs; i++) { setobjs2s(L, L->top++, fixed+i); setnilvalue(fixed+i); } /* add `arg' parameter */ if (htab) { sethvalue(L, L->top++, htab); lua_assert(iswhite(obj2gco(htab))); } return base;}static StkId tryfuncTM (lua_State *L, StkId func) { const TValue *tm = luaT_gettmbyobj(L, func, TM_CALL); StkId p; ptrdiff_t funcr = savestack(L, func); if (!ttisfunction(tm)) luaG_typeerror(L, func, "call"); /* Open a hole inside the stack at `func' */ for (p = L->top; p > func; p--) setobjs2s(L, p, p-1); incr_top(L); func = restorestack(L, funcr); /* previous call may change stack */ setobj2s(L, func, tm); /* tag method is the new function to be called */ return func;}#define inc_ci(L) \ ((L->ci == L->end_ci) ? growCI(L) : \ (condhardstacktests(luaD_reallocCI(L, L->size_ci)), ++L->ci))int luaD_precall (lua_State *L, StkId func, int nresults) { LClosure *cl; ptrdiff_t funcr; if (!ttisfunction(func)) /* `func' is not a function? */ func = tryfuncTM(L, func); /* check the `function' tag method */ funcr = savestack(L, func); cl = &clvalue(func)->l; L->ci->savedpc = L->savedpc; if (!cl->isC) { /* Lua function? prepare its call */ CallInfo *ci; StkId st, base; Proto *p = cl->p; luaD_checkstack(L, p->maxstacksize); func = restorestack(L, funcr); if (!p->is_vararg) { /* no varargs? */ base = func + 1; if (L->top > base + p->numparams) L->top = base + p->numparams; } else { /* vararg function */ int nargs = cast_int(L->top - func) - 1; base = adjust_varargs(L, p, nargs); func = restorestack(L, funcr); /* previous call may change the stack */ } ci = inc_ci(L); /* now `enter' new function */ ci->func = func; L->base = ci->base = base; ci->top = L->base + p->maxstacksize; lua_assert(ci->top <= L->stack_last); L->savedpc = p->code; /* starting point */ ci->tailcalls = 0; ci->nresults = nresults; for (st = L->top; st < ci->top; st++) setnilvalue(st); L->top = ci->top; if (L->hookmask & LUA_MASKCALL) { L->savedpc++; /* hooks assume 'pc' is already incremented */ luaD_callhook(L, LUA_HOOKCALL, -1); L->savedpc--; /* correct 'pc' */ } return PCRLUA; } else { /* if is a C function, call it */ CallInfo *ci; int n; luaD_checkstack(L, LUA_MINSTACK); /* ensure minimum stack size */ ci = inc_ci(L); /* now `enter' new function */ ci->func = restorestack(L, funcr); L->base = ci->base = ci->func + 1; ci->top = L->top + LUA_MINSTACK; lua_assert(ci->top <= L->stack_last); ci->nresults = nresults; if (L->hookmask & LUA_MASKCALL) luaD_callhook(L, LUA_HOOKCALL, -1); lua_unlock(L); n = (*curr_func(L)->c.f)(L); /* do the actual call */ lua_lock(L); if (n < 0) /* yielding? */ return PCRYIELD; else { luaD_poscall(L, L->top - n); return PCRC; } }}static StkId callrethooks (lua_State *L, StkId firstResult) { ptrdiff_t fr = savestack(L, firstResult); /* next call may change stack */ luaD_callhook(L, LUA_HOOKRET, -1); if (f_isLua(L->ci)) { /* Lua function? */ while ((L->hookmask & LUA_MASKRET) && L->ci->tailcalls--) /* tail calls */ luaD_callhook(L, LUA_HOOKTAILRET, -1); } return restorestack(L, fr);}int luaD_poscall (lua_State *L, StkId firstResult) { StkId res; int wanted, i; CallInfo *ci; if (L->hookmask & LUA_MASKRET) firstResult = callrethooks(L, firstResult); ci = L->ci--; res = ci->func; /* res == final position of 1st result */ wanted = ci->nresults; L->base = (ci - 1)->base; /* restore base */ L->savedpc = (ci - 1)->savedpc; /* restore savedpc */ /* move results to correct place */ for (i = wanted; i != 0 && firstResult < L->top; i--) setobjs2s(L, res++, firstResult++); while (i-- > 0) setnilvalue(res++); L->top = res; return (wanted - LUA_MULTRET); /* 0 iff wanted == LUA_MULTRET */}/*** Call a function (C or Lua). The function to be called is at *func.** The arguments are on the stack, right after the function.** When returns, all the results are on the stack, starting at the original** function position.*/ void luaD_call (lua_State *L, StkId func, int nResults) { if (++L->nCcalls >= LUAI_MAXCCALLS) { if (L->nCcalls == LUAI_MAXCCALLS) luaG_runerror(L, "C stack overflow"); else if (L->nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) luaD_throw(L, LUA_ERRERR); /* error while handing stack error */ } if (luaD_precall(L, func, nResults) == PCRLUA) /* is a Lua function? */ luaV_execute(L, 1); /* call it */ L->nCcalls--; luaC_checkGC(L);}static void resume (lua_State *L, void *ud) { StkId firstArg = cast(StkId, ud); CallInfo *ci = L->ci; if (L->status == 0) { /* start coroutine? */ lua_assert(ci == L->base_ci && firstArg > L->base); if (luaD_precall(L, firstArg - 1, LUA_MULTRET) != PCRLUA) return; } else { /* resuming from previous yield */ lua_assert(L->status == LUA_YIELD); L->status = 0; if (!f_isLua(ci)) { /* `common' yield? */ /* finish interrupted execution of `OP_CALL' */ lua_assert(GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_CALL || GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_TAILCALL); if (luaD_poscall(L, firstArg)) /* complete it... */ L->top = L->ci->top; /* and correct top if not multiple results */ } else /* yielded inside a hook: just continue its execution */ L->base = L->ci->base; } luaV_execute(L, cast_int(L->ci - L->base_ci));}static int resume_error (lua_State *L, const char *msg) { L->top = L->ci->base; setsvalue2s(L, L->top, luaS_new(L, msg)); incr_top(L); lua_unlock(L); return LUA_ERRRUN;}LUA_API int lua_resume (lua_State *L, int nargs) { int status; lua_lock(L); if (L->status != LUA_YIELD && (L->status != 0 || L->ci != L->base_ci)) return resume_error(L, "cannot resume non-suspended coroutine"); if (L->nCcalls >= LUAI_MAXCCALLS) return resume_error(L, "C stack overflow"); luai_userstateresume(L, nargs); lua_assert(L->errfunc == 0); L->baseCcalls = ++L->nCcalls; status = luaD_rawrunprotected(L, resume, L->top - nargs); if (status != 0) { /* error? */ L->status = cast_byte(status); /* mark thread as `dead' */ luaD_seterrorobj(L, status, L->top); L->ci->top = L->top; } else { lua_assert(L->nCcalls == L->baseCcalls); status = L->status; } --L->nCcalls; lua_unlock(L); return status;}LUA_API int lua_yield (lua_State *L, int nresults) { luai_userstateyield(L, nresults); lua_lock(L); if (L->nCcalls > L->baseCcalls) luaG_runerror(L, "attempt to yield across metamethod/C-call boundary"); L->base = L->top - nresults; /* protect stack slots below */ L->status = LUA_YIELD; lua_unlock(L); return -1;}int luaD_pcall (lua_State *L, Pfunc func, void *u, ptrdiff_t old_top, ptrdiff_t ef) { int status; unsigned short oldnCcalls = L->nCcalls; ptrdiff_t old_ci = saveci(L, L->ci); lu_byte old_allowhooks = L->allowhook; ptrdiff_t old_errfunc = L->errfunc; L->errfunc = ef; status = luaD_rawrunprotected(L, func, u); if (status != 0) { /* an error occurred? */ StkId oldtop = restorestack(L, old_top); luaF_close(L, oldtop); /* close eventual pending closures */ luaD_seterrorobj(L, status, oldtop); L->nCcalls = oldnCcalls; L->ci = restoreci(L, old_ci); L->base = L->ci->base; L->savedpc = L->ci->savedpc; L->allowhook = old_allowhooks; restore_stack_limit(L); } L->errfunc = old_errfunc; return status;}/*** Execute a protected parser.*/struct SParser { /* data to `f_parser' */ ZIO *z; Mbuffer buff; /* buffer to be used by the scanner */ const char *name;};static void f_parser (lua_State *L, void *ud) { int i; Proto *tf; Closure *cl; struct SParser *p = cast(struct SParser *, ud); int c = luaZ_lookahead(p->z); luaC_checkGC(L); tf = ((c == LUA_SIGNATURE[0]) ? luaU_undump : luaY_parser)(L, p->z, &p->buff, p->name); cl = luaF_newLclosure(L, tf->nups, hvalue(gt(L))); cl->l.p = tf; for (i = 0; i < tf->nups; i++) /* initialize eventual upvalues */ cl->l.upvals[i] = luaF_newupval(L); setclvalue(L, L->top, cl); incr_top(L);}int luaD_protectedparser (lua_State *L, ZIO *z, const char *name) { struct SParser p; int status; p.z = z; p.name = name; luaZ_initbuffer(L, &p.buff); status = luaD_pcall(L, f_parser, &p, savestack(L, L->top), L->errfunc); luaZ_freebuffer(L, &p.buff); return status;}
