/*
** $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);
}
}
}
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;
}