lex.c

gcc-2.95.3 Linux下最常用的C编译器

    case 'Z':
    case 'a':                                   case 'e':
    case 'f':  case 'g':             case 'i':  case 'j':
    case 'k':  case 'l':  case 'm':  case 'n':
    case 'p':  case 'q':  case 'r':  case 's':  case 't':
    case 'u':  case 'v':  case 'w':  case 'x':  case 'y':
    case 'z':
    case '_':
    letter:
      return handle_name (read_identifier (ch));
    case '\'':
      tmp = readstring ('\'', &len);
      yylval.ttype = string_or_char (len, tmp);
      free (tmp);
      return len == 1 ? SINGLECHAR : STRING;
    case '\"':
      tmp = readstring ('\"', &len);
      yylval.ttype = build_chill_string (len, tmp);
      free (tmp);
      return STRING;
    case '.':
      nextc = input ();
      unput (nextc);
      if (ISDIGIT (nextc)) /* || nextc == '_')  we don't start numbers with '_' */
	goto number;
      return DOT;
    case '0': case '1': case '2': case '3': case '4':
    case '5': case '6': case '7': case '8': case '9':
    number:
      yylval.ttype = read_number (ch);
      return TREE_CODE (yylval.ttype) == REAL_CST ? FLOATING : NUMBER;
    default:
      return ch;
    }
}

static void
close_input_file (fn)
  char *fn;
{
  if (finput == NULL)
    abort ();

  if (finput != stdin && fclose (finput) == EOF)
    {
      error ("can't close %s", fn);
      abort ();
    }
  finput = NULL;
}

/* Return an identifier, starting with FIRST and then reading
   more characters using input().  Return an IDENTIFIER_NODE. */

static tree
read_identifier (first)
     int first; /* First letter of identifier */
{
  tree id;
  char *start;
  for (;;)
    {
      obstack_1grow (&temporary_obstack, first);
      first = input ();
      if (first == EOF)
	break;
      if (! ISALNUM (first) && first != '_')
	{
	  unput (first);
	  break;
	}
    }
  obstack_1grow (&temporary_obstack, '\0');
  start = obstack_finish (&temporary_obstack);
  maybe_downcase (start);
  id = get_identifier (start);
  obstack_free (&temporary_obstack, start);
  return id;
}

/* Given an identifier ID, check to see if it is a reserved name,
   and return the appropriate token type. */

static int
handle_name (id)
     tree id;
{
  struct resword *tp;
  tp = in_word_set (IDENTIFIER_POINTER (id), IDENTIFIER_LENGTH (id));
  if (tp != NULL
      && special_UC == ISUPPER ((unsigned char) tp->name[0])
      && (tp->flags == RESERVED || tp->flags == PREDEF))
    {
      if (tp->rid != NORID)
	yylval.ttype = ridpointers[tp->rid];
      else if (tp->token == THIS)
	yylval.ttype = lookup_name (get_identifier ("__whoami"));
      return tp->token;
    }
  yylval.ttype = id;
  return NAME;
}

static tree
read_number (ch)
     int ch; /* Initial character */
{
  tree num;
  char *start;
  int is_float = 0;
  for (;;)
    {
      if (ch != '_')
	obstack_1grow (&temporary_obstack, ch);
      ch = input ();
      if (! ISDIGIT (ch) && ch != '_')
	break;
    }
  if (ch == '.')
    {
      do
	{
	  if (ch != '_')
	    obstack_1grow (&temporary_obstack, ch);
	  ch = input ();
	} while (ISDIGIT (ch) || ch == '_');
      is_float++;
    }
  if (ch == 'd' || ch == 'D' || ch == 'e' || ch == 'E')
    {
      /* Convert exponent indication [eEdD] to 'e'. */
      obstack_1grow (&temporary_obstack, 'e');
      ch = input ();
      if (ch == '+' || ch == '-')
	{
	  obstack_1grow (&temporary_obstack, ch);
	  ch = input ();
	}
      if (ISDIGIT (ch) || ch == '_')
	{
	  do
	    {
	      if (ch != '_')
		obstack_1grow (&temporary_obstack, ch);
	      ch = input ();
	    } while (ISDIGIT (ch) || ch == '_');
	}
      else
	{
	  error ("malformed exponent part of floating-point literal");
	}
      is_float++;
    }
  if (ch != EOF)
    unput (ch);
  obstack_1grow (&temporary_obstack, '\0');
  start = obstack_finish (&temporary_obstack);
  if (is_float)
    {
      REAL_VALUE_TYPE value;
      tree  type = double_type_node;
      errno = 0;
      value = REAL_VALUE_ATOF (start, TYPE_MODE (type));
      obstack_free (&temporary_obstack, start);
      if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
	  && REAL_VALUE_ISINF (value) && pedantic)
	pedwarn ("real number exceeds range of REAL");
      num = build_real (type, value);
    }
  else
    num = convert_integer (start);
  CH_DERIVED_FLAG (num) = 1;
  return num;
}

/* Skip to the end of a compiler directive. */

static void
skip_directive ()
{
  int ch = input ();
  for (;;)
    {
      if (ch == EOF)
	{
	  error ("end-of-file in '<>' directive");
	  break;
	}
      if (ch == '\n')
	break;
      if (ch == '<')
	{
	  ch = input ();
	  if (ch == '>')
	    break;
	}
      ch = input ();
    }
  starting_pass_2 = 0;
}

/* Read a compiler directive.  ("<>{WS}" have already been read. ) */
static void
read_directive ()
{
  struct resword *tp;
  tree id;
  int ch = skip_whitespace();
  if (ISALPHA (ch) || ch == '_')
    id = read_identifier (ch);
  else if (ch == EOF)
    {
      error ("end-of-file in '<>' directive"); 
      to_global_binding_level (); 
      return;
    }
  else
    {
      warning ("unrecognized compiler directive");
      skip_directive ();
      return;
    }
  tp = in_word_set (IDENTIFIER_POINTER (id), IDENTIFIER_LENGTH (id));
  if (tp == NULL || special_UC != ISUPPER ((unsigned char) tp->name[0]))
    {
      if (pass == 1)
	warning ("unrecognized compiler directive `%s'",
		 IDENTIFIER_POINTER (id));
    }
  else
    switch (tp->token)
      {
      case ALL_STATIC_OFF:
	all_static_flag = 0;
	break;
      case ALL_STATIC_ON:
	all_static_flag = 1;
	break;
      case EMPTY_OFF:
	empty_checking = 0;
	break;
      case EMPTY_ON:
	empty_checking = 1;
	break;
      case IGNORED_DIRECTIVE:
	break;
      case PROCESS_TYPE_TOKEN:
	process_type = equal_number ();
	break;
      case RANGE_OFF:
	range_checking = 0;
	break;
      case RANGE_ON:
	range_checking = 1;
	break;
      case SEND_SIGNAL_DEFAULT_PRIORITY: 
	send_signal_prio = equal_number ();
	break;
      case SEND_BUFFER_DEFAULT_PRIORITY:
	send_buffer_prio = equal_number ();
	break;
      case SIGNAL_CODE:
	signal_code = equal_number ();
	break;
      case USE_SEIZE_FILE:
	handle_use_seizefile_directive (0);
	break;
      case USE_SEIZE_FILE_RESTRICTED:
	handle_use_seizefile_directive (1);
	break;
      default:
	if (pass == 1)
	  warning ("unrecognized compiler directive `%s'", 
		   IDENTIFIER_POINTER (id));
	break;
      }
  skip_directive ();
}


tree
build_chill_string (len, str)
    int   len;
    char  *str;
{
  tree t;

  push_obstacks (&permanent_obstack, &permanent_obstack);
  t = build_string (len, str);
  TREE_TYPE (t) = build_string_type (char_type_node, 
				     build_int_2 (len, 0));
  CH_DERIVED_FLAG (t) = 1;
  pop_obstacks ();
  return t;
}


static tree
string_or_char (len, str)
     int   len;
     char *str;
{
  tree result;
  
  push_obstacks (&permanent_obstack, &permanent_obstack);
  if (len == 1)
    {
      result = build_int_2 ((unsigned char)str[0], 0);
      CH_DERIVED_FLAG (result) = 1;
      TREE_TYPE (result) = char_type_node;
    }
  else
    result = build_chill_string (len, str);
  pop_obstacks ();
  return result;
}


static void
maybe_downcase (str)
    char        *str;
{
  if (! ignore_case)
    return;
  while (*str)
    {
      if (ISUPPER ((unsigned char) *str))
	*str = tolower ((unsigned char)*str);
      str++;
    }
}


static int
maybe_number (s)
  char	*s;
{
  char	fc;
  
  /* check for decimal number */
  if (*s >= '0' && *s <= '9')
    {
      while (*s)
	{
	  if (*s >= '0' && *s <= '9')
	    s++;
	  else
	    return 0;
	}
      return 1;
    }
  
  fc = *s;
  if (s[1] != '\'')
    return 0;
  s += 2;
  while (*s)
    {
      switch (fc)
	{
	case 'd':
	case 'D':
	  if (*s < '0' || *s > '9')
	    return 0;
	  break;
	case 'h':
	case 'H':
	  if (!ISXDIGIT ((unsigned char) *s))
	    return 0;
	  break;
	case 'b':
	case 'B':
	  if (*s < '0' || *s > '1')
	    return 0;
	  break;
	case 'o':
	case 'O':
	  if (*s < '0' || *s > '7')
	    return 0;
	  break;
	default:
	  return 0;
	}
      s++;
    }
  return 1;
}

static char *
readstring (terminator, len)
     char terminator;
     int *len;
{
  int      c;
  unsigned allocated = 1024;
  char    *tmp = xmalloc (allocated);
  unsigned i = 0;
  
  for (;;)
    {
      c = input ();
      if (c == terminator)
	{
	  if ((c = input ()) != terminator)
	    {
	      unput (c);
	      break;
	    }
	  else
	    c = terminator;
	}
      if (c == '\n' || c == EOF)
	  goto unterminated;
      if (c == '^')
	{
	  c = input();
	  if (c == EOF || c == '\n')
	    goto unterminated;
	  if (c == '^')
	    goto storeit;
	  if (c == '(')
	    {
	      int cc, count = 0;
	      int base = 10;
	      int next_apos = 0;
	      int check_base = 1;
	      c = 0;
	      while (1)
		{
		  cc = input ();
		  if (cc == terminator)
		    {
		      if (!(terminator == '\'' && next_apos))
			{
			  error ("unterminated control sequence");
			  serious_errors++;
			  goto done;
			}
		    }
		  if (cc == EOF || cc == '\n')
		    {
		      c = cc;
		      goto unterminated;
		    }
		  if (next_apos)
		    {
		      next_apos = 0;
		      if (cc != '\'')
			{
			  error ("invalid integer literal in control sequence");
			  serious_errors++;
			  goto done;
			}
		      continue;
		    }
		  if (cc == ' ' || cc == '\t')
		    continue;
		  if (cc == ')')
		    {
		      if ((c < 0 || c > 255) && (pass == 1))
			error ("control sequence overflow");
		      if (! count && pass == 1)
			error ("invalid control sequence");
		      break;
		    }
		  else if (cc == ',')
		    {
		      if ((c < 0 || c > 255) && (pass == 1))
			error ("control sequence overflow");
		      if (! count && pass == 1)
			error ("invalid control sequence");
		      tmp[i++] = c;
		      if (i == allocated)
			{
			  allocated += 1024;
			  tmp = xrealloc (tmp, allocated);
			}
		      c = count = 0;
		      base = 10;
		      check_base = 1;
		      continue;
		    }
		  else if (cc == '_')
		    {
		      if (! count && pass == 1)
			error ("invalid integer literal in control sequence");
		      continue;
		    }
		  if (check_base)
		    {
		      if (cc == 'D' || cc == 'd')
			{
			  base = 10;
			  next_apos = 1;
			}
		      else if (cc == 'H' || cc == 'h')
			{
			  base = 16;
			  next_apos = 1;
			}
		      else if (cc == 'O' || cc == 'o')
			{
			  base = 8;
			  next_apos = 1;
			}
		      else if (cc == 'B' || cc == 'b')
			{
			  base = 2;
			  next_apos = 1;
			}
		      check_base = 0;
		      if (next_apos)
			continue;
		    }
		  if (base == 2)
		    {
		      if (cc < '0' || cc > '1')
			cc = -1;
		      else
			cc -= '0';
		    }
		  else if (base == 8)
		    {
		      if (cc < '0' || cc > '8')
			cc = -1;
		      else
			cc -= '0';
		    }
		  else if (base == 10)
		    {
		      if (! ISDIGIT (cc))
			cc = -1;
		      else
			cc -= '0';
		    }
		  else if (base == 16)
		    {
		      if (!ISXDIGIT (cc))
			cc = -1;
		      else
			{
			  if (cc >= 'a')
			    cc -= ' ';
			  cc -= '0';
			  if (cc > 9)
			    cc -= 7;
			}
		    }
		  else
		    {
		      error ("invalid base in read control sequence");
		      abort ();
		    }
		  if (cc == -1)
		    {
		      /* error in control sequence */
		      if (pass == 1)