c-common.c

来自「GCC编译器源代码」· C语言 代码 · 共 2,225 行 · 第 1/5 页

		   || TREE_CODE (decl) == VAR_DECL
		   || TREE_CODE (decl) == FUNCTION_DECL)
	    TREE_USED (decl) = 1;
	  else
	    warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
	  break;

	case A_CONST:
	  if (TREE_CODE (decl) == FUNCTION_DECL)
	    TREE_READONLY (decl) = 1;
	  else if (TREE_CODE (type) == POINTER_TYPE
		   && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
	    TREE_TYPE (decl) = type
	      = build_pointer_type
		(build_type_variant (TREE_TYPE (type), 1,
				     TREE_THIS_VOLATILE (TREE_TYPE (type))));
	  else
	    warning ( "`%s' attribute ignored", IDENTIFIER_POINTER (name));
	  break;

	case A_T_UNION:
	  if (is_type
	      && TREE_CODE (type) == UNION_TYPE
	      && (decl == 0
		  || (TYPE_FIELDS (type) != 0
		      && TYPE_MODE (type) == DECL_MODE (TYPE_FIELDS (type)))))
	    TYPE_TRANSPARENT_UNION (type) = 1;
	  else if (decl != 0 && TREE_CODE (decl) == PARM_DECL
		   && TREE_CODE (type) == UNION_TYPE
		   && TYPE_MODE (type) == DECL_MODE (TYPE_FIELDS (type)))
	    DECL_TRANSPARENT_UNION (decl) = 1;
	  else
	    warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
	  break;

	case A_CONSTRUCTOR:
	  if (TREE_CODE (decl) == FUNCTION_DECL
	      && TREE_CODE (type) == FUNCTION_TYPE
	      && decl_function_context (decl) == 0)
	    {
	      DECL_STATIC_CONSTRUCTOR (decl) = 1;
	      TREE_USED (decl) = 1;
	    }
	  else
	    warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
	  break;

	case A_DESTRUCTOR:
	  if (TREE_CODE (decl) == FUNCTION_DECL
	      && TREE_CODE (type) == FUNCTION_TYPE
	      && decl_function_context (decl) == 0)
	    {
	      DECL_STATIC_DESTRUCTOR (decl) = 1;
	      TREE_USED (decl) = 1;
	    }
	  else
	    warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
	  break;

	case A_MODE:
	  if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
	    warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
	  else
	    {
	      int j;
	      char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
	      int len = strlen (p);
	      enum machine_mode mode = VOIDmode;
	      tree typefm;

	      if (len > 4 && p[0] == '_' && p[1] == '_'
		  && p[len - 1] == '_' && p[len - 2] == '_')
		{
		  char *newp = (char *) alloca (len - 1);

		  strcpy (newp, &p[2]);
		  newp[len - 4] = '\0';
		  p = newp;
		}

	      /* Give this decl a type with the specified mode.
		 First check for the special modes.  */
	      if (! strcmp (p, "byte"))
		mode = byte_mode;
	      else if (!strcmp (p, "word"))
		mode = word_mode;
	      else if (! strcmp (p, "pointer"))
		mode = ptr_mode;
	      else
		for (j = 0; j < NUM_MACHINE_MODES; j++)
		  if (!strcmp (p, GET_MODE_NAME (j)))
		    mode = (enum machine_mode) j;

	      if (mode == VOIDmode)
		error ("unknown machine mode `%s'", p);
	      else if (0 == (typefm = type_for_mode (mode,
						     TREE_UNSIGNED (type))))
		error ("no data type for mode `%s'", p);
	      else
		{
		  TREE_TYPE (decl) = type = typefm;
		  DECL_SIZE (decl) = 0;
		  layout_decl (decl, 0);
		}
	    }
	  break;

	case A_SECTION:
#ifdef ASM_OUTPUT_SECTION_NAME
	  if ((TREE_CODE (decl) == FUNCTION_DECL
	       || TREE_CODE (decl) == VAR_DECL)
	      && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
	    {
	      if (TREE_CODE (decl) == VAR_DECL 
		  && current_function_decl != NULL_TREE
		  && ! TREE_STATIC (decl))
		error_with_decl (decl,
		  "section attribute cannot be specified for local variables");
	      /* The decl may have already been given a section attribute from
		 a previous declaration.  Ensure they match.  */
	      else if (DECL_SECTION_NAME (decl) != NULL_TREE
		       && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
				  TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
		error_with_decl (node,
				 "section of `%s' conflicts with previous declaration");
	      else
		DECL_SECTION_NAME (decl) = TREE_VALUE (args);
	    }
	  else
	    error_with_decl (node,
			   "section attribute not allowed for `%s'");
#else
	  error_with_decl (node,
		  "section attributes are not supported for this target");
#endif
	  break;

	case A_ALIGNED:
	  {
	    tree align_expr
	      = (args ? TREE_VALUE (args)
		 : size_int (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
	    int align;

	    /* Strip any NOPs of any kind.  */
	    while (TREE_CODE (align_expr) == NOP_EXPR
		   || TREE_CODE (align_expr) == CONVERT_EXPR
		   || TREE_CODE (align_expr) == NON_LVALUE_EXPR)
	      align_expr = TREE_OPERAND (align_expr, 0);
	  
	    if (TREE_CODE (align_expr) != INTEGER_CST)
	      {
		error ("requested alignment is not a constant");
		continue;
	      }

	    align = TREE_INT_CST_LOW (align_expr) * BITS_PER_UNIT;

	    if (exact_log2 (align) == -1)
	      error ("requested alignment is not a power of 2");
	    else if (is_type)
	      TYPE_ALIGN (type) = align;
	    else if (TREE_CODE (decl) != VAR_DECL
		     && TREE_CODE (decl) != FIELD_DECL)
	      error_with_decl (decl,
			       "alignment may not be specified for `%s'");
	    else
	      DECL_ALIGN (decl) = align;
	  }
	  break;

	case A_FORMAT:
	  {
	    tree format_type = TREE_VALUE (args);
	    tree format_num_expr = TREE_VALUE (TREE_CHAIN (args));
	    tree first_arg_num_expr
	      = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (args)));
	    int format_num;
	    int first_arg_num;
	    int is_scan;
	    tree argument;
	    int arg_num;
	
	    if (TREE_CODE (decl) != FUNCTION_DECL)
	      {
		error_with_decl (decl,
			 "argument format specified for non-function `%s'");
		continue;
	      }
	
	    if (TREE_CODE (format_type) == IDENTIFIER_NODE
		&& (!strcmp (IDENTIFIER_POINTER (format_type), "printf")
		    || !strcmp (IDENTIFIER_POINTER (format_type),
				"__printf__")))
	      is_scan = 0;
	    else if (TREE_CODE (format_type) == IDENTIFIER_NODE
		     && (!strcmp (IDENTIFIER_POINTER (format_type), "scanf")
			 || !strcmp (IDENTIFIER_POINTER (format_type),
				     "__scanf__")))
	      is_scan = 1;
	    else if (TREE_CODE (format_type) == IDENTIFIER_NODE)
	      {
		error ("`%s' is an unrecognized format function type",
		       IDENTIFIER_POINTER (format_type));
		continue;
	      }
	    else
	      {
		error ("unrecognized format specifier");
		continue;
	      }

	    /* Strip any conversions from the string index and first arg number
	       and verify they are constants.  */
	    while (TREE_CODE (format_num_expr) == NOP_EXPR
		   || TREE_CODE (format_num_expr) == CONVERT_EXPR
		   || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR)
	      format_num_expr = TREE_OPERAND (format_num_expr, 0);

	    while (TREE_CODE (first_arg_num_expr) == NOP_EXPR
		   || TREE_CODE (first_arg_num_expr) == CONVERT_EXPR
		   || TREE_CODE (first_arg_num_expr) == NON_LVALUE_EXPR)
	      first_arg_num_expr = TREE_OPERAND (first_arg_num_expr, 0);

	    if (TREE_CODE (format_num_expr) != INTEGER_CST
		|| TREE_CODE (first_arg_num_expr) != INTEGER_CST)
	      {
		error ("format string has non-constant operand number");
		continue;
	      }

	    format_num = TREE_INT_CST_LOW (format_num_expr);
	    first_arg_num = TREE_INT_CST_LOW (first_arg_num_expr);
	    if (first_arg_num != 0 && first_arg_num <= format_num)
	      {
		error ("format string arg follows the args to be formatted");
		continue;
	      }

	    /* If a parameter list is specified, verify that the format_num
	       argument is actually a string, in case the format attribute
	       is in error.  */
	    argument = TYPE_ARG_TYPES (type);
	    if (argument)
	      {
		for (arg_num = 1; ; ++arg_num)
		  {
		    if (argument == 0 || arg_num == format_num)
		      break;
		    argument = TREE_CHAIN (argument);
		  }
		if (! argument
		    || TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE
		  || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (argument)))
		      != char_type_node))
		  {
		    error ("format string arg not a string type");
		    continue;
		  }
		if (first_arg_num != 0)
		  {
		    /* Verify that first_arg_num points to the last arg,
		       the ...  */
		    while (argument)
		      arg_num++, argument = TREE_CHAIN (argument);
		  if (arg_num != first_arg_num)
		    {
		      error ("args to be formatted is not ...");
		      continue;
		    }
		  }
	      }

	    record_function_format (DECL_NAME (decl),
				    DECL_ASSEMBLER_NAME (decl),
				    is_scan, format_num, first_arg_num);
	    break;
	  }

	case A_FORMAT_ARG:
	  {
	    tree format_num_expr = TREE_VALUE (args);
	    int format_num, arg_num;
	    tree argument;
	
	    if (TREE_CODE (decl) != FUNCTION_DECL)
	      {
		error_with_decl (decl,
			 "argument format specified for non-function `%s'");
		continue;
	      }
	
	    /* Strip any conversions from the first arg number and verify it
	       is a constant.  */
	    while (TREE_CODE (format_num_expr) == NOP_EXPR
		   || TREE_CODE (format_num_expr) == CONVERT_EXPR
		   || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR)
	      format_num_expr = TREE_OPERAND (format_num_expr, 0);

	    if (TREE_CODE (format_num_expr) != INTEGER_CST)
	      {
		error ("format string has non-constant operand number");
		continue;
	      }

	    format_num = TREE_INT_CST_LOW (format_num_expr);

	    /* If a parameter list is specified, verify that the format_num
	       argument is actually a string, in case the format attribute
	       is in error.  */
	    argument = TYPE_ARG_TYPES (type);
	    if (argument)
	      {
		for (arg_num = 1; ; ++arg_num)
		  {
		    if (argument == 0 || arg_num == format_num)
		      break;
		    argument = TREE_CHAIN (argument);
		  }
		if (! argument
		    || TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE
		  || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (argument)))
		      != char_type_node))
		  {
		    error ("format string arg not a string type");
		    continue;
		  }
	      }

	    if (TREE_CODE (TREE_TYPE (TREE_TYPE (decl))) != POINTER_TYPE
		|| (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (TREE_TYPE (decl))))
		    != char_type_node))
	      {
		error ("function does not return string type");
		continue;
	      }

	    record_international_format (DECL_NAME (decl),
					 DECL_ASSEMBLER_NAME (decl),
					 format_num);
	    break;
	  }

	case A_WEAK:
	  declare_weak (decl);
	  break;

	case A_ALIAS:
	  if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
	      || (TREE_CODE (decl) != FUNCTION_DECL && ! DECL_EXTERNAL (decl)))
	    error_with_decl (decl,
			     "`%s' defined both normally and as an alias");
	  else if (decl_function_context (decl) == 0)
	    {
	      tree id = get_identifier (TREE_STRING_POINTER
					(TREE_VALUE (args)));
	      if (TREE_CODE (decl) == FUNCTION_DECL)
		DECL_INITIAL (decl) = error_mark_node;
	      else
		DECL_EXTERNAL (decl) = 0;
	      assemble_alias (decl, id);
	    }
	  else
	    warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
	  break;
	}
    }
}

/* Split SPECS_ATTRS, a list of declspecs and prefix attributes, into two
   lists.  SPECS_ATTRS may also be just a typespec (eg: RECORD_TYPE).

   The head of the declspec list is stored in DECLSPECS.
   The head of the attribute list is stored in PREFIX_ATTRIBUTES.

   Note that attributes in SPECS_ATTRS are stored in the TREE_PURPOSE of
   the list elements.  We drop the containing TREE_LIST nodes and link the
   resulting attributes together the way decl_attributes expects them.  */

void
split_specs_attrs (specs_attrs, declspecs, prefix_attributes)
     tree specs_attrs;
     tree *declspecs, *prefix_attributes;
{
  tree t, s, a, next, specs, attrs;

  /* This can happen in c++ (eg: decl: typespec initdecls ';').  */
  if (specs_attrs != NULL_TREE
      && TREE_CODE (specs_attrs) != TREE_LIST)
    {
      *declspecs = specs_attrs;
      *prefix_attributes = NULL_TREE;
      return;
    }

  /* Remember to keep the lists in the same order, element-wise.  */

  specs = s = NULL_TREE;
  attrs = a = NULL_TREE;
  for (t = specs_attrs; t; t = next)
    {
      next = TREE_CHAIN (t);
      /* Declspecs have a non-NULL TREE_VALUE.  */
      if (TREE_VALUE (t) != NULL_TREE)
	{
	  if (specs == NULL_TREE)
	    specs = s = t;
	  else
	    {
	      TREE_CHAIN (s) = t;
	      s = t;
	    }
	}
      else
	{
	  if (attrs == NULL_TREE)
	    attrs = a = TREE_PURPOSE (t);
	  else
	    {
	      TREE_CHAIN (a) = TREE_PURPOSE (t);
	      a = TREE_PURPOSE (t);
	    }
	  /* More attrs can be linked here, move A to the end.  */
	  while (TREE_CHAIN (a) != NULL_TREE)
	    a = TREE_CHAIN (a);
	}
    }

  /* Terminate the lists.  */
  if (s != NULL_TREE)
    TREE_CHAIN (s) = NULL_TREE;
  if (a != NULL_TREE)
    TREE_CHAIN (a) = NULL_TREE;

  /* All done.  */
  *declspecs = specs;
  *prefix_attributes = attrs;
}

/* Check a printf/fprintf/sprintf/scanf/fscanf/sscanf format against
   a parameter list.  */

#define T_I	&integer_type_node
#define T_L	&long_integer_type_node
#define T_LL	&long_long_integer_type_node