diff options
author | Kartik K. Agaram <vc@akkartik.com> | 2021-10-19 21:38:48 -0700 |
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committer | Kartik K. Agaram <vc@akkartik.com> | 2021-10-22 19:24:44 -0700 |
commit | 74f8cd15bb43110973deffdeb9dd229797e5b328 (patch) | |
tree | 12d6b5475a786eacf7a5a79b03b2b85621578ec6 /src/ldo.c | |
download | teliva-74f8cd15bb43110973deffdeb9dd229797e5b328.tar.gz |
new fork of Lua 5.1
https://www.lua.org
Diffstat (limited to 'src/ldo.c')
-rw-r--r-- | src/ldo.c | 519 |
1 files changed, 519 insertions, 0 deletions
diff --git a/src/ldo.c b/src/ldo.c new file mode 100644 index 0000000..d1bf786 --- /dev/null +++ b/src/ldo.c @@ -0,0 +1,519 @@ +/* +** $Id: ldo.c,v 2.38.1.4 2012/01/18 02:27:10 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); + luaD_checkstack(L, p->maxstacksize); + 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; +} + + |