/*** $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;}