TValue * LJ_FASTCALL lj_meta_equal_cd(lua_State *L, BCIns ins)
{
  ASMFunction cont = (bc_op(ins) & 1) ? lj_cont_condf : lj_cont_condt;
  int op = (int)bc_op(ins) & ~1;
  TValue tv;
  cTValue *mo, *o2, *o1 = &L->base[bc_a(ins)];
  cTValue *o1mm = o1;
  if (op == BC_ISEQV) {
    o2 = &L->base[bc_d(ins)];
    if (!tviscdata(o1mm)) o1mm = o2;
  } else if (op == BC_ISEQS) {
    setstrV(L, &tv, gco2str(proto_kgc(curr_proto(L), ~(ptrdiff_t)bc_d(ins))));
    o2 = &tv;
  } else if (op == BC_ISEQN) {
    o2 = &mref(curr_proto(L)->k, cTValue)[bc_d(ins)];
  } else {
    lua_assert(op == BC_ISEQP);
    setitype(&tv, ~bc_d(ins));
    o2 = &tv;
  }
  mo = lj_meta_lookup(L, o1mm, MM_eq);
  if (LJ_LIKELY(!tvisnil(mo)))
    return mmcall(L, cont, mo, o1, o2);
  else
    return (TValue *)(intptr_t)(bc_op(ins) & 1);
}

/* Out-of-memory error. */
LJ_NOINLINE void lj_err_mem(lua_State *L)
{
  if (L->status == LUA_ERRERR+1)  /* Don't touch the stack during lua_open. */
    lj_vm_unwind_c(L->cframe, LUA_ERRMEM);
  setstrV(L, L->top++, lj_err_str(L, LJ_ERR_ERRMEM));
  lj_err_throw(L, LUA_ERRMEM);
}

/* Win64 exception handler for interpreter frame. */
LJ_FUNCA EXCEPTION_DISPOSITION lj_err_unwind_win64(EXCEPTION_RECORD *rec,
  void *cf, CONTEXT *ctx, UndocumentedDispatcherContext *dispatch)
{
  lua_State *L = cframe_L(cf);
  int errcode = LJ_EXCODE_CHECK(rec->ExceptionCode) ?
		LJ_EXCODE_ERRCODE(rec->ExceptionCode) : LUA_ERRRUN;
  if ((rec->ExceptionFlags & 6)) {  /* EH_UNWINDING|EH_EXIT_UNWIND */
    /* Unwind internal frames. */
    err_unwind(L, cf, errcode);
  } else {
    void *cf2 = err_unwind(L, cf, 0);
    if (cf2) {  /* We catch it, so start unwinding the upper frames. */
      if (rec->ExceptionCode == LJ_MSVC_EXCODE ||
	  rec->ExceptionCode == LJ_GCC_EXCODE) {
	__DestructExceptionObject(rec, 1);
	setstrV(L, L->top++, lj_err_str(L, LJ_ERR_ERRCPP));
      } else if (!LJ_EXCODE_CHECK(rec->ExceptionCode)) {
	/* Don't catch access violations etc. */
	return ExceptionContinueSearch;
      }
      /* Unwind the stack and call all handlers for all lower C frames
      ** (including ourselves) again with EH_UNWINDING set. Then set
      ** rsp = cf, rax = errcode and jump to the specified target.
      */
      RtlUnwindEx(cf, (void *)((cframe_unwind_ff(cf2) && errcode != LUA_YIELD) ?
			       lj_vm_unwind_ff_eh :
			       lj_vm_unwind_c_eh),
		  rec, (void *)(uintptr_t)errcode, ctx, dispatch->HistoryTable);
      /* RtlUnwindEx should never return. */
    }
  }
  return ExceptionContinueSearch;
}

/* Push a string for every flag bit that is set. */
static void flagbits_to_strings(lua_State *L, uint32_t flags, uint32_t base,
				const char *str)
{
  for (; *str; base <<= 1, str += 1+*str)
    if (flags & base)
      setstrV(L, L->top++, lj_str_new(L, str+1, *(uint8_t *)str));
}

/* DWARF2 personality handler referenced from interpreter .eh_frame. */
LJ_FUNCA int lj_err_unwind_dwarf(int version, int actions,
  uint64_t uexclass, _Unwind_Exception *uex, _Unwind_Context *ctx)
{
  void *cf;
  lua_State *L;
  if (version != 1)
    return _URC_FATAL_PHASE1_ERROR;
  UNUSED(uexclass);
  cf = (void *)_Unwind_GetCFA(ctx);
  L = cframe_L(cf);
  if ((actions & _UA_SEARCH_PHASE)) {
#if LJ_UNWIND_EXT
    if (err_unwind(L, cf, 0) == NULL)
      return _URC_CONTINUE_UNWIND;
#endif
    if (!LJ_UEXCLASS_CHECK(uexclass)) {
      setstrV(L, L->top++, lj_err_str(L, LJ_ERR_ERRCPP));
    }
    return _URC_HANDLER_FOUND;
  }
  if ((actions & _UA_CLEANUP_PHASE)) {
    int errcode;
    if (LJ_UEXCLASS_CHECK(uexclass)) {
      errcode = LJ_UEXCLASS_ERRCODE(uexclass);
    } else {
      if ((actions & _UA_HANDLER_FRAME))
	_Unwind_DeleteException(uex);
      errcode = LUA_ERRRUN;
    }
#if LJ_UNWIND_EXT
    cf = err_unwind(L, cf, errcode);
    if ((actions & _UA_FORCE_UNWIND)) {
      return _URC_CONTINUE_UNWIND;
    } else if (cf) {
      _Unwind_SetGR(ctx, LJ_TARGET_EHRETREG, errcode);
      _Unwind_SetIP(ctx, (uintptr_t)(cframe_unwind_ff(cf) ?
				     lj_vm_unwind_ff_eh :
				     lj_vm_unwind_c_eh));
      return _URC_INSTALL_CONTEXT;
    }
#if LJ_TARGET_X86ORX64
    else if ((actions & _UA_HANDLER_FRAME)) {
      /* Workaround for ancient libgcc bug. Still present in RHEL 5.5. :-/
      ** Real fix: http://gcc.gnu.org/viewcvs/trunk/gcc/unwind-dw2.c?r1=121165&r2=124837&pathrev=153877&diff_format=h
      */
      _Unwind_SetGR(ctx, LJ_TARGET_EHRETREG, errcode);
      _Unwind_SetIP(ctx, (uintptr_t)lj_vm_unwind_rethrow);
      return _URC_INSTALL_CONTEXT;
    }
#endif
#else
    /* This is not the proper way to escape from the unwinder. We get away with
    ** it on non-x64 because the interpreter restores all callee-saved regs.
    */
    lj_err_throw(L, errcode);
#endif
  }
  return _URC_CONTINUE_UNWIND;
}

/* Protection twiddling failed. Probably due to kernel security. */
static LJ_NOINLINE void mcode_protfail(jit_State *J)
{
  lua_CFunction panic = J2G(J)->panic;
  if (panic) {
    lua_State *L = J->L;
    setstrV(L, L->top++, lj_err_str(L, LJ_ERR_JITPROT));
    panic(L);
  }
}

/* In-place coercion of a number to a string. */
static LJ_AINLINE int tostring(lua_State *L, TValue *o)
{
  if (tvisstr(o)) {
    return 1;
  } else if (tvisnumber(o)) {
    setstrV(L, o, lj_str_fromnumber(L, o));
    return 1;
  } else {
    return 0;
  }
}

static void read_string(LexState *ls, int delim, TValue *tv)
{
  save_and_next(ls);
  while (ls->current != delim) {
    switch (ls->current) {
    case END_OF_STREAM:
      lj_lex_error(ls, TK_eof, LJ_ERR_XSTR);
      continue;
    case '\n':
    case '\r':
      lj_lex_error(ls, TK_string, LJ_ERR_XSTR);
      continue;
    case '\\': {
      int c;
      next(ls);  /* do not save the `\' */
      switch (ls->current) {
      case 'a': c = '\a'; break;
      case 'b': c = '\b'; break;
      case 'f': c = '\f'; break;
      case 'n': c = '\n'; break;
      case 'r': c = '\r'; break;
      case 't': c = '\t'; break;
      case 'v': c = '\v'; break;
      case '\n': case '\r': save(ls, '\n'); inclinenumber(ls); continue;
      case END_OF_STREAM: continue;  /* will raise an error next loop */
      default:
	if (!lj_ctype_isdigit(ls->current)) {
	  save_and_next(ls);  /* handles \\, \", \', and \? */
	} else {  /* \xxx */
	  int i = 0;
	  c = 0;
	  do {
	    c = 10*c + (ls->current-'0');
	    next(ls);
	  } while (++i<3 && lj_ctype_isdigit(ls->current));
	  if (c > UCHAR_MAX)
	    lj_lex_error(ls, TK_string, LJ_ERR_XESC);
	  save(ls, c);
	}
	continue;
      }
      save(ls, c);
      next(ls);
      continue;
      }
    default:
      save_and_next(ls);
      break;
    }
  }
  save_and_next(ls);  /* skip delimiter */
  setstrV(ls->L, tv, lj_parse_keepstr(ls, ls->sb.buf + 1, ls->sb.n - 2));
}

static void io_file_readall(lua_State *L, FILE *fp)
{
  MSize m, n;
  for (m = LUAL_BUFFERSIZE, n = 0; ; m += m) {
    char *buf = lj_str_needbuf(L, &G(L)->tmpbuf, m);
    n += (MSize)fread(buf+n, 1, m-n, fp);
    if (n != m) {
      setstrV(L, L->top++, lj_str_new(L, buf, (size_t)n));
      lj_gc_check(L);
      return;
    }
  }
}

GCstr *lj_lib_checkstr(lua_State *L, int narg)
{
  TValue *o = L->base + narg-1;
  if (o < L->top) {
    if (LJ_LIKELY(tvisstr(o))) {
      return strV(o);
    } else if (tvisnumber(o)) {
      GCstr *s = lj_str_fromnumber(L, o);
      setstrV(L, o, s);
      return s;
    }
  }
  lj_err_argt(L, narg, LUA_TSTRING);
  return NULL;  /* unreachable */
}

static int io_file_readline(lua_State *L, FILE *fp, MSize chop)
{
  MSize m = LUAL_BUFFERSIZE, n = 0, ok = 0;
  char *buf;
  for (;;) {
    buf = lj_str_needbuf(L, &G(L)->tmpbuf, m);
    if (fgets(buf+n, m-n, fp) == NULL) break;
    n += (MSize)strlen(buf+n);
    ok |= n;
    if (n && buf[n-1] == '\n') { n -= chop; break; }
    if (n >= m - 64) m += m;
  }
  setstrV(L, L->top++, lj_str_new(L, buf, (size_t)n));
  lj_gc_check(L);
  return (int)ok;
}

/* Get runtime value of string argument. */
static GCstr *argv2str(jit_State *J, TValue *o)
{
  if (LJ_LIKELY(tvisstr(o))) {
    return strV(o);
  } else {
    GCstr *s;
    if (!tvisnumber(o))
      lj_trace_err(J, LJ_TRERR_BADTYPE);
    if (tvisint(o))
      s = lj_str_fromint(J->L, intV(o));
    else
      s = lj_str_fromnum(J->L, &o->n);
    setstrV(J->L, o, s);
    return s;
  }
}

/* Setup lexer state. */
int lj_lex_setup(lua_State *L, LexState *ls)
{
  int header = 0;
  ls->L = L;
  ls->fs = NULL;
  ls->n = 0;
  ls->p = NULL;
  ls->vstack = NULL;
  ls->sizevstack = 0;
  ls->vtop = 0;
  ls->bcstack = NULL;
  ls->sizebcstack = 0;
  ls->lookahead = TK_eof;  /* No look-ahead token. */
  ls->linenumber = 1;
  ls->lastline = 1;
  lj_str_resizebuf(ls->L, &ls->sb, LJ_MIN_SBUF);
  next(ls);  /* Read-ahead first char. */
  if (ls->current == 0xef && ls->n >= 2 && char2int(ls->p[0]) == 0xbb &&
      char2int(ls->p[1]) == 0xbf) {  /* Skip UTF-8 BOM (if buffered). */
    ls->n -= 2;
    ls->p += 2;
    next(ls);
    header = 1;
  }
  if (ls->current == '#') {  /* Skip POSIX #! header line. */
    do {
      next(ls);
      if (ls->current == END_OF_STREAM) return 0;
    } while (!currIsNewline(ls));
    inclinenumber(ls);
    header = 1;
  }
  if (ls->current == LUA_SIGNATURE[0]) {  /* Bytecode dump. */
    if (header) {
      /*
      ** Loading bytecode with an extra header is disabled for security
      ** reasons. This may circumvent the usual check for bytecode vs.
      ** Lua code by looking at the first char. Since this is a potential
      ** security violation no attempt is made to echo the chunkname either.
      */
      setstrV(L, L->top++, lj_err_str(L, LJ_ERR_BCBAD));
      lj_err_throw(L, LUA_ERRSYNTAX);
    }
    return 1;
  }
  return 0;
}

/* Runtime error. */
LJ_NOINLINE void lj_err_run(lua_State *L)
{
  ptrdiff_t ef = finderrfunc(L);
  if (ef) {
    TValue *errfunc = restorestack(L, ef);
    TValue *top = L->top;
    lj_trace_abort(G(L));
    if (!tvisfunc(errfunc) || L->status == LUA_ERRERR) {
      setstrV(L, top-1, lj_err_str(L, LJ_ERR_ERRERR));
      lj_err_throw(L, LUA_ERRERR);
    }
    L->status = LUA_ERRERR;
    copyTV(L, top, top-1);
    copyTV(L, top-1, errfunc);
    L->top = top+1;
    lj_vm_call(L, top, 1+1);  /* Stack: |errfunc|msg| -> |msg| */
  }
  lj_err_throw(L, LUA_ERRRUN);
}

static TValue *cpparser(lua_State *L, lua_CFunction dummy, void *ud)
{
  LexState *ls = (LexState *)ud;
  GCproto *pt;
  GCfunc *fn;
  int bc;
  UNUSED(dummy);
  cframe_errfunc(L->cframe) = -1;  /* Inherit error function. */
  bc = lj_lex_setup(L, ls);
  if (ls->mode && !strchr(ls->mode, bc ? 'b' : 't')) {
    setstrV(L, L->top++, lj_err_str(L, LJ_ERR_XMODE));
    lj_err_throw(L, LUA_ERRSYNTAX);
  }
  pt = bc ? lj_bcread(ls) : lj_parse(ls);
  fn = lj_func_newL_empty(L, pt, tabref(L->env));
  /* Don't combine above/below into one statement. */
  setfuncV(L, L->top++, fn);
  return NULL;
}

/* ARM unwinder personality handler referenced from interpreter .ARM.extab. */
LJ_FUNCA int lj_err_unwind_arm(int state, void *ucb, _Unwind_Context *ctx)
{
  void *cf = (void *)_Unwind_GetGR(ctx, 13);
  lua_State *L = cframe_L(cf);
  if ((state & _US_ACTION_MASK) == _US_VIRTUAL_UNWIND_FRAME) {
    setstrV(L, L->top++, lj_err_str(L, LJ_ERR_ERRCPP));
    return _URC_HANDLER_FOUND;
  }
  if ((state&(_US_ACTION_MASK|_US_FORCE_UNWIND)) == _US_UNWIND_FRAME_STARTING) {
    _Unwind_DeleteException(ucb);
    _Unwind_SetGR(ctx, 15, (uint32_t)(void *)lj_err_throw);
    _Unwind_SetGR(ctx, 0, (uint32_t)L);
    _Unwind_SetGR(ctx, 1, (uint32_t)LUA_ERRRUN);
    return _URC_INSTALL_CONTEXT;
  }
  if (__gnu_unwind_frame(ucb, ctx) != _URC_OK)
    return _URC_FAILURE;
  return _URC_CONTINUE_UNWIND;
}

static void jit_profile_callback(lua_State *L2, lua_State *L, int samples,
				 int vmstate)
{
  TValue key;
  cTValue *tv;
  setlightudV(&key, (void *)&KEY_PROFILE_FUNC);
  tv = lj_tab_get(L, tabV(registry(L)), &key);
  if (tvisfunc(tv)) {
    char vmst = (char)vmstate;
    int status;
    setfuncV(L2, L2->top++, funcV(tv));
    setthreadV(L2, L2->top++, L);
    setintV(L2->top++, samples);
    setstrV(L2, L2->top++, lj_str_new(L2, &vmst, 1));
    status = lua_pcall(L2, 3, 0, 0);  /* callback(thread, samples, vmstate) */
    if (status) {
      if (G(L2)->panic) G(L2)->panic(L2);
      exit(EXIT_FAILURE);
    }
    lj_trace_abort(G(L2));
  }
}

static int llex(LexState *ls, TValue *tv)
{
  lj_str_resetbuf(&ls->sb);
  for (;;) {
    if (lj_char_isident(ls->current)) {
      GCstr *s;
      if (lj_char_isdigit(ls->current)) {  /* Numeric literal. */
	lex_number(ls, tv);
	return TK_number;
      }
      /* Identifier or reserved word. */
      do {
	save_and_next(ls);
      } while (lj_char_isident(ls->current));
      s = lj_parse_keepstr(ls, ls->sb.buf, ls->sb.n);
      setstrV(ls->L, tv, s);
      if (s->reserved > 0)  /* Reserved word? */
	return TK_OFS + s->reserved;
      return TK_name;
    }
    switch (ls->current) {
    case '\n':
    case '\r':
      inclinenumber(ls);
      continue;
    case ' ':
    case '\t':
    case '\v':
    case '\f':
      next(ls);
      continue;
    case '-':
      next(ls);
      if (ls->current != '-') return '-';
      /* else is a comment */
      next(ls);
      if (ls->current == '[') {
	int sep = skip_sep(ls);
	lj_str_resetbuf(&ls->sb);  /* `skip_sep' may dirty the buffer */
	if (sep >= 0) {
	  read_long_string(ls, NULL, sep);  /* long comment */
	  lj_str_resetbuf(&ls->sb);
	  continue;
	}
      }
      /* else short comment */
      while (!currIsNewline(ls) && ls->current != END_OF_STREAM)
	next(ls);
      continue;
    case '[': {
      int sep = skip_sep(ls);
      if (sep >= 0) {
	read_long_string(ls, tv, sep);
	return TK_string;
      } else if (sep == -1) {
	return '[';
      } else {
	lj_lex_error(ls, TK_string, LJ_ERR_XLDELIM);
	continue;
      }
      }
    case '=':
      next(ls);
      if (ls->current != '=') return '='; else { next(ls); return TK_eq; }
    case '<':
      next(ls);
      if (ls->current != '=') return '<'; else { next(ls); return TK_le; }
    case '>':
      next(ls);
      if (ls->current != '=') return '>'; else { next(ls); return TK_ge; }
    case '~':
      next(ls);
      if (ls->current != '=') return '~'; else { next(ls); return TK_ne; }
    case ':':
      next(ls);
      if (ls->current != ':') return ':'; else { next(ls); return TK_label; }
    case '"':
    case '\'':
      read_string(ls, ls->current, tv);
      return TK_string;
    case '.':
      save_and_next(ls);
      if (ls->current == '.') {
	next(ls);
	if (ls->current == '.') {
	  next(ls);
	  return TK_dots;   /* ... */
	}
	return TK_concat;   /* .. */
      } else if (!lj_char_isdigit(ls->current)) {
	return '.';
      } else {
	lex_number(ls, tv);
	return TK_number;
      }
    case END_OF_STREAM:
      return TK_eof;
    default: {
      int c = ls->current;
      next(ls);
//.........这里部分代码省略.........

static void read_string(LexState *ls, int delim, TValue *tv)
{
  save_and_next(ls);
  while (ls->current != delim) {
    switch (ls->current) {
    case END_OF_STREAM:
      lj_lex_error(ls, TK_eof, LJ_ERR_XSTR);
      continue;
    case '\n':
    case '\r':
      lj_lex_error(ls, TK_string, LJ_ERR_XSTR);
      continue;
    case '\\': {
      int c = next(ls);  /* Skip the '\\'. */
      switch (c) {
      case 'a': c = '\a'; break;
      case 'b': c = '\b'; break;
      case 'f': c = '\f'; break;
      case 'n': c = '\n'; break;
      case 'r': c = '\r'; break;
      case 't': c = '\t'; break;
      case 'v': c = '\v'; break;
      case 'x':  /* Hexadecimal escape '\xXX'. */
	c = (next(ls) & 15u) << 4;
	if (!lj_char_isdigit(ls->current)) {
	  if (!lj_char_isxdigit(ls->current)) goto err_xesc;
	  c += 9 << 4;
	}
	c += (next(ls) & 15u);
	if (!lj_char_isdigit(ls->current)) {
	  if (!lj_char_isxdigit(ls->current)) goto err_xesc;
	  c += 9;
	}
	break;
      case 'z':  /* Skip whitespace. */
	next(ls);
	while (lj_char_isspace(ls->current))
	  if (currIsNewline(ls)) inclinenumber(ls); else next(ls);
	continue;
      case '\n': case '\r': save(ls, '\n'); inclinenumber(ls); continue;
      case '\\': case '\"': case '\'': break;
      case END_OF_STREAM: continue;
      default:
	if (!lj_char_isdigit(c))
	  goto err_xesc;
	c -= '0';  /* Decimal escape '\ddd'. */
	if (lj_char_isdigit(next(ls))) {
	  c = c*10 + (ls->current - '0');
	  if (lj_char_isdigit(next(ls))) {
	    c = c*10 + (ls->current - '0');
	    if (c > 255) {
	    err_xesc:
	      lj_lex_error(ls, TK_string, LJ_ERR_XESC);
	    }
	    next(ls);
	  }
	}
	save(ls, c);
	continue;
      }
      save(ls, c);
      next(ls);
      continue;
      }
    default:
      save_and_next(ls);
      break;
    }
  }
  save_and_next(ls);  /* skip delimiter */
  setstrV(ls->L, tv, lj_parse_keepstr(ls, ls->sb.buf + 1, ls->sb.n - 2));
}

/* Helper for CAT. Coercion, iterative concat, __concat metamethod. */
TValue *lj_meta_cat(lua_State *L, TValue *top, int left)
{
  do {
    int n = 1;
    if (!(tvisstr(top-1) || tvisnumber(top-1)) || !tostring(L, top)) {
      cTValue *mo = lj_meta_lookup(L, top-1, MM_concat);
      if (tvisnil(mo)) {
	mo = lj_meta_lookup(L, top, MM_concat);
	if (tvisnil(mo)) {
	  if (tvisstr(top-1) || tvisnumber(top-1)) top++;
	  lj_err_optype(L, top-1, LJ_ERR_OPCAT);
	  return NULL;  /* unreachable */
	}
      }
      /* One of the top two elements is not a string, call __cat metamethod:
      **
      ** before:    [...][CAT stack .........................]
      **                                 top-1     top         top+1 top+2
      ** pick two:  [...][CAT stack ...] [o1]      [o2]
      ** setup mm:  [...][CAT stack ...] [cont|?]  [mo|tmtype] [o1]  [o2]
      ** in asm:    [...][CAT stack ...] [cont|PC] [mo|delta]  [o1]  [o2]
      **            ^-- func base                              ^-- mm base
      ** after mm:  [...][CAT stack ...] <--push-- [result]
      ** next step: [...][CAT stack .............]
      */
      copyTV(L, top+2, top);  /* Careful with the order of stack copies! */
      copyTV(L, top+1, top-1);
      copyTV(L, top, mo);
      setcont(top-1, lj_cont_cat);
      return top+1;  /* Trigger metamethod call. */
    } else if (strV(top)->len == 0) {  /* Shortcut. */
      (void)tostring(L, top-1);
    } else {
      /* Pick as many strings as possible from the top and concatenate them:
      **
      ** before:    [...][CAT stack ...........................]
      ** pick str:  [...][CAT stack ...] [...... strings ......]
      ** concat:    [...][CAT stack ...] [result]
      ** next step: [...][CAT stack ............]
      */
      MSize tlen = strV(top)->len;
      char *buffer;
      int i;
      for (n = 1; n <= left && tostring(L, top-n); n++) {
	MSize len = strV(top-n)->len;
	if (len >= LJ_MAX_STR - tlen)
	  lj_err_msg(L, LJ_ERR_STROV);
	tlen += len;
      }
      buffer = lj_str_needbuf(L, &G(L)->tmpbuf, tlen);
      n--;
      tlen = 0;
      for (i = n; i >= 0; i--) {
	MSize len = strV(top-i)->len;
	memcpy(buffer + tlen, strVdata(top-i), len);
	tlen += len;
      }
      setstrV(L, top-n, lj_str_new(L, buffer, tlen));
    }
    left -= n;
    top -= n;
  } while (left >= 1);
  lj_gc_check_fixtop(L);
  return NULL;
}