lex.c

gcc-2.95.3 Linux下最常用的C编译器

	if (TREE_PURPOSE (defarg_parm)
	    && TREE_CODE (TREE_PURPOSE (defarg_parm)) == DEFAULT_ARG)
	  {
	    feed_defarg (defarg_fn, defarg_parm);

	    /* Return to the parser, which will process this defarg
	       and call us again.  */
	    return;
	  }

      if (TREE_CODE (defarg_fn) == FUNCTION_DECL)
	{
	  maybe_end_member_template_processing ();
	  check_default_args (defarg_fn);
	}

      poplevel (0, 0, 0);
      pop_nested_class ();
    }
}

/* Build a default function named NAME for type TYPE.
   KIND says what to build.

   When KIND == 0, build default destructor.
   When KIND == 1, build virtual destructor.
   When KIND == 2, build default constructor.
   When KIND == 3, build default X(const X&) constructor.
   When KIND == 4, build default X(X&) constructor.
   When KIND == 5, build default operator = (const X&).
   When KIND == 6, build default operator = (X&).  */

tree
cons_up_default_function (type, full_name, kind)
     tree type, full_name;
     int kind;
{
  extern tree void_list_node;
  tree declspecs = NULL_TREE;
  tree fn, args = NULL_TREE;
  tree argtype;
  int retref = 0;
  tree name = constructor_name (full_name);

  switch (kind)
    {
      /* Destructors.  */
    case 1:
      declspecs = build_decl_list (NULL_TREE, ridpointers [(int) RID_VIRTUAL]);
      /* Fall through...  */
    case 0:
      name = build_parse_node (BIT_NOT_EXPR, name);
      args = void_list_node;
      break;

    case 2:
      /* Default constructor.  */
      args = void_list_node;
      break;

    case 3:
      type = build_qualified_type (type, TYPE_QUAL_CONST);
      /* Fall through...  */
    case 4:
      /* According to ARM $12.8, the default copy ctor will be declared, but
	 not defined, unless it's needed.  */
      argtype = build_reference_type (type);
      args = tree_cons (NULL_TREE,
			build_tree_list (hash_tree_chain (argtype, NULL_TREE),
					 get_identifier ("_ctor_arg")),
			void_list_node);
      break;

    case 5:
    case 6:
      retref = 1;
      declspecs = build_decl_list (NULL_TREE, type);

      if (kind == 5)
	type = build_qualified_type (type, TYPE_QUAL_CONST);

      name = ansi_opname [(int) MODIFY_EXPR];

      argtype = build_reference_type (type);
      args = tree_cons (NULL_TREE,
			build_tree_list (hash_tree_chain (argtype, NULL_TREE),
					 get_identifier ("_ctor_arg")),
			void_list_node);
      break;

    default:
      my_friendly_abort (59);
    }

  declspecs = decl_tree_cons (NULL_TREE, ridpointers [(int) RID_INLINE],
			      declspecs);

  TREE_PARMLIST (args) = 1;

  {
    tree declarator = make_call_declarator (name, args, NULL_TREE, NULL_TREE);
    if (retref)
      declarator = build_parse_node (ADDR_EXPR, declarator);

    fn = grokfield (declarator, declspecs, NULL_TREE, NULL_TREE, NULL_TREE);
  }
  
  if (fn == void_type_node)
    return fn;

  if (kind > 2)
    SET_DECL_ARTIFICIAL (TREE_CHAIN (DECL_ARGUMENTS (fn)));

#if 0
  if (processing_template_defn)
    {
      SET_DECL_IMPLICIT_INSTANTIATION (fn);
      repo_template_used (fn);
    }
#endif

#if 0
  if (CLASSTYPE_INTERFACE_KNOWN (type))
    {
      DECL_INTERFACE_KNOWN (fn) = 1;
      DECL_NOT_REALLY_EXTERN (fn) = (!CLASSTYPE_INTERFACE_ONLY (type)
				     && flag_implement_inlines);
    }
  else
#endif
    DECL_NOT_REALLY_EXTERN (fn) = 1;

  mark_inline_for_output (fn);

#ifdef DEBUG_DEFAULT_FUNCTIONS
  { char *fn_type = NULL;
    tree t = name;
    switch (kind)
      {
      case 0: fn_type = "default destructor"; break;
      case 1: fn_type = "virtual destructor"; break;
      case 2: fn_type = "default constructor"; break;
      case 3: fn_type = "default X(const X&)"; break;
      case 4: fn_type = "default X(X&)"; break;
      }
    if (fn_type)
      {
	if (TREE_CODE (name) == BIT_NOT_EXPR)
	  t = TREE_OPERAND (name, 0);
	fprintf (stderr, "[[[[ %s for %s:\n%s]]]]\n", fn_type,
		 IDENTIFIER_POINTER (t), func_buf);
      }
  }
#endif /* DEBUG_DEFAULT_FUNCTIONS */

  /* Show that this function was generated by the compiler.  */
  SET_DECL_ARTIFICIAL (fn);
  
  return fn;
}

/* Heuristic to tell whether the user is missing a semicolon
   after a struct or enum declaration.  Emit an error message
   if we know the user has blown it.  */

void
check_for_missing_semicolon (type)
     tree type;
{
  if (yychar < 0)
    yychar = yylex ();

  if ((yychar > 255
       && yychar != SCSPEC
       && yychar != IDENTIFIER
       && yychar != TYPENAME
       && yychar != CV_QUALIFIER
       && yychar != SELFNAME)
      || end_of_file)
    {
      if (ANON_AGGRNAME_P (TYPE_IDENTIFIER (type)))
	error ("semicolon missing after %s declaration",
	       TREE_CODE (type) == ENUMERAL_TYPE ? "enum" : "struct");
      else
	cp_error ("semicolon missing after declaration of `%T'", type);
      shadow_tag (build_tree_list (0, type));
    }
  /* Could probably also hack cases where class { ... } f (); appears.  */
  clear_anon_tags ();
}

void
note_got_semicolon (type)
     tree type;
{
  if (TREE_CODE_CLASS (TREE_CODE (type)) != 't')
    my_friendly_abort (60);
  if (CLASS_TYPE_P (type))
    CLASSTYPE_GOT_SEMICOLON (type) = 1;
}

void
note_list_got_semicolon (declspecs)
     tree declspecs;
{
  tree link;

  for (link = declspecs; link; link = TREE_CHAIN (link))
    {
      tree type = TREE_VALUE (link);
      if (TREE_CODE_CLASS (TREE_CODE (type)) == 't')
	note_got_semicolon (type);
    }
  clear_anon_tags ();
}

/* If C is not whitespace, return C.
   Otherwise skip whitespace and return first nonwhite char read.  */

static int
skip_white_space (c)
     register int c;
{
  for (;;)
    {
      switch (c)
	{
	case '\n':
	  c = check_newline ();
	  break;

	case ' ':
	case '\t':
	case '\f':
	case '\r':
	case '\v':
	case '\b':
	  do
	    c = getch ();
	  while (c == ' ' || c == '\t');
	  break;

	case '\\':
	  c = getch ();
	  if (c == '\n')
	    lineno++;
	  else
	    error ("stray '\\' in program");
	  c = getch ();
	  break;

	default:
	  return (c);
	}
    }
}



/* Make the token buffer longer, preserving the data in it.
   P should point to just beyond the last valid character in the old buffer.
   The value we return is a pointer to the new buffer
   at a place corresponding to P.  */

static char *
extend_token_buffer (p)
     const char *p;
{
  int offset = p - token_buffer;

  maxtoken = maxtoken * 2 + 10;
  token_buffer = (char *) xrealloc (token_buffer, maxtoken + 2);

  return token_buffer + offset;
}

static int
get_last_nonwhite_on_line ()
{
  register int c;

  /* Is this the last nonwhite stuff on the line?  */
  if (nextchar >= 0)
    c = nextchar, nextchar = -1;
  else
    c = getch ();

  while (c == ' ' || c == '\t')
    c = getch ();
  return c;
}

#if defined HANDLE_PRAGMA
/* Local versions of these macros, that can be passed as function pointers.  */
static int
pragma_getc ()
{
  int c;
      
  if (nextchar != EOF)
    {
      c = nextchar;
      nextchar = EOF;
    }
  else
    c = getch ();

  return c;
}

static void
pragma_ungetc (arg)
     int arg;
{
  yyungetc (arg, 0);
}
#endif /* HANDLE_PRAGMA */

/* At the beginning of a line, increment the line number
   and process any #-directive on this line.
   If the line is a #-directive, read the entire line and return a newline.
   Otherwise, return the line's first non-whitespace character.  */

int linemode;

static int
check_newline ()
{
  register int c;
  register int token;
  int saw_line = 0;

  /* Read first nonwhite char on the line.  Do this before incrementing the
     line number, in case we're at the end of saved text.  */

  do
    c = getch ();
  while (c == ' ' || c == '\t');

  lineno++;

  if (c != '#')
    {
      /* If not #, return it so caller will use it.  */
      return c;
    }

  /* Don't read beyond this line.  */
  linemode = 1;
  
  /* Read first nonwhite char after the `#'.  */

  do
    c = getch ();
  while (c == ' ' || c == '\t');

  /* If a letter follows, then if the word here is `line', skip
     it and ignore it; otherwise, ignore the line, with an error
     if the word isn't `pragma'.  */

  if (ISALPHA (c))
    {
      if (c == 'p')
	{
	  if (getch () == 'r'
	      && getch () == 'a'
	      && getch () == 'g'
	      && getch () == 'm'
	      && getch () == 'a')
	    {
	      token = real_yylex ();
	      if (token == IDENTIFIER
		  && TREE_CODE (yylval.ttype) == IDENTIFIER_NODE)
		{
		  /* If this is 1, we handled it; if it's -1, it was one we
		     wanted but had something wrong with it.  Only if it's
		     0 was it not handled.  */
		  if (handle_cp_pragma (IDENTIFIER_POINTER (yylval.ttype)))
		    goto skipline;
		}
	      else if (token == END_OF_LINE)
		goto skipline;

#ifdef HANDLE_PRAGMA
	      /* We invoke HANDLE_PRAGMA before HANDLE_GENERIC_PRAGMAS
		 (if both are defined), in order to give the back
		 end a chance to override the interpretation of
		 SYSV style pragmas.  */
	      if (HANDLE_PRAGMA (pragma_getc, pragma_ungetc,
				 IDENTIFIER_POINTER (yylval.ttype)))
		goto skipline;
#endif /* HANDLE_PRAGMA */
	      
#ifdef HANDLE_GENERIC_PRAGMAS
	      if (handle_generic_pragma (token))
		goto skipline;
#endif /* HANDLE_GENERIC_PRAGMAS */

	      /* Issue a warning message if we have been asked to do so.
		 Ignoring unknown pragmas in system header file unless
		 an explcit -Wunknown-pragmas has been given. */
	      if (warn_unknown_pragmas > 1
		  || (warn_unknown_pragmas && ! in_system_header))
		warning ("ignoring pragma: %s", token_buffer);
	    }
	  
	  goto skipline;
	}
      else if (c == 'd')
	{
	  if (getch () == 'e'
	      && getch () == 'f'
	      && getch () == 'i'
	      && getch () == 'n'
	      && getch () == 'e'
	      && ((c = getch ()) == ' ' || c == '\t'))
	    {
	      debug_define (lineno, GET_DIRECTIVE_LINE ());
	      goto skipline;
	    }
	}
      else if (c == 'u')
	{
	  if (getch () == 'n'
	      && getch () == 'd'
	      && getch () == 'e'
	      && getch () == 'f'
	      && ((c = getch ()) == ' ' || c == '\t'))
	    {
	      debug_undef (lineno, GET_DIRECTIVE_LINE ());
	      goto skipline;
	    }
	}
      else if (c == 'l')
	{
	  if (getch () == 'i'
	      && getch () == 'n'
	      && getch () == 'e'
	      && ((c = getch ()) == ' ' || c == '\t'))
	    {
	      saw_line = 1;
	      goto linenum;
	    }
	}
      else if (c == 'i')
	{
	  if (getch () == 'd'
	      && getch () == 'e'
	      && getch () == 'n'
	      && getch () == 't'
	      && ((c = getch ()) == ' ' || c == '\t'))
	    {
	      /* #ident.  The pedantic warning is now in cccp.c.  */

	      /* Here we have just seen `#ident '.
		 A string constant should follow.  */

	      token = real_yylex ();
	      if (token == END_OF_LINE)
		goto skipline;
	      if (token != STRING
		  || TREE_CODE (yylval.ttype) != STRING_CST)
		{
		  error ("invalid #ident");
		  goto ski