gcc/attribs.h

/* Declarations and definitions dealing with attribute handling.
   Copyright (C) 2013-2018 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#ifndef GCC_ATTRIBS_H
#define GCC_ATTRIBS_H

extern const struct attribute_spec *lookup_attribute_spec (const_tree);
extern void init_attributes (void);

/* Process the attributes listed in ATTRIBUTES and install them in *NODE,
   which is either a DECL (including a TYPE_DECL) or a TYPE.  If a DECL,
   it should be modified in place; if a TYPE, a copy should be created
   unless ATTR_FLAG_TYPE_IN_PLACE is set in FLAGS.  FLAGS gives further
   information, in the form of a bitwise OR of flags in enum attribute_flags
   from tree.h.  Depending on these flags, some attributes may be
   returned to be applied at a later stage (for example, to apply
   a decl attribute to the declaration rather than to its type).  */
extern tree decl_attributes (tree *, tree, int, tree = NULL_TREE);

extern bool cxx11_attribute_p (const_tree);
extern tree get_attribute_name (const_tree);
extern void apply_tm_attr (tree, tree);
extern tree make_attribute (const char *, const char *, tree);

extern struct scoped_attributes* register_scoped_attributes (const struct attribute_spec *,
							     const char *);

extern char *sorted_attr_string (tree);
extern bool common_function_versions (tree, tree);
extern char *make_unique_name (tree, const char *, bool);
extern tree make_dispatcher_decl (const tree);
extern bool is_function_default_version (const tree);

/* Return a type like TTYPE except that its TYPE_ATTRIBUTES
   is ATTRIBUTE.

   Such modified types already made are recorded so that duplicates
   are not made.  */

extern tree build_type_attribute_variant (tree, tree);
extern tree build_decl_attribute_variant (tree, tree);
extern tree build_type_attribute_qual_variant (tree, tree, int);

extern bool attribute_value_equal (const_tree, const_tree);

/* Return 0 if the attributes for two types are incompatible, 1 if they
   are compatible, and 2 if they are nearly compatible (which causes a
   warning to be generated).  */
extern int comp_type_attributes (const_tree, const_tree);

/* Default versions of target-overridable functions.  */
extern tree merge_decl_attributes (tree, tree);
extern tree merge_type_attributes (tree, tree);

/* Remove any instances of attribute ATTR_NAME in LIST and return the
   modified list.  */

extern tree remove_attribute (const char *, tree);

/* Given two attributes lists, return a list of their union.  */

extern tree merge_attributes (tree, tree);

/* Duplicate all attributes with name NAME in ATTR list to *ATTRS if
   they are missing there.  */

extern void duplicate_one_attribute (tree *, tree, const char *);

/* Duplicate all attributes from user DECL to the corresponding
   builtin that should be propagated.  */

extern void copy_attributes_to_builtin (tree);

/* Given two Windows decl attributes lists, possibly including
   dllimport, return a list of their union .  */
extern tree merge_dllimport_decl_attributes (tree, tree);

/* Handle a "dllimport" or "dllexport" attribute.  */
extern tree handle_dll_attribute (tree *, tree, tree, int, bool *);

extern int attribute_list_equal (const_tree, const_tree);
extern int attribute_list_contained (const_tree, const_tree);

/* The backbone of lookup_attribute().  ATTR_LEN is the string length
   of ATTR_NAME, and LIST is not NULL_TREE.

   The function is called from lookup_attribute in order to optimize
   for size.  */
extern tree private_lookup_attribute (const char *attr_name, size_t attr_len,
				      tree list);

/* For a given IDENTIFIER_NODE, strip leading and trailing '_' characters
   so that we have a canonical form of attribute names.  */

static inline tree
canonicalize_attr_name (tree attr_name)
{
  const size_t l = IDENTIFIER_LENGTH (attr_name);
  const char *s = IDENTIFIER_POINTER (attr_name);

  if (l > 4 && s[0] == '_' && s[1] == '_' && s[l - 1] == '_' && s[l - 2] == '_')
    return get_identifier_with_length (s + 2, l - 4);

  return attr_name;
}

/* Compare attribute identifiers ATTR1 and ATTR2 with length ATTR1_LEN and
   ATTR2_LEN.  */

static inline bool
cmp_attribs (const char *attr1, size_t attr1_len,
	     const char *attr2, size_t attr2_len)
{
  return attr1_len == attr2_len && strncmp (attr1, attr2, attr1_len) == 0;
}

/* Compare attribute identifiers ATTR1 and ATTR2.  */

static inline bool
cmp_attribs (const char *attr1, const char *attr2)
{
  return cmp_attribs (attr1, strlen (attr1), attr2, strlen (attr2));
}

/* Given an identifier node IDENT and a string ATTR_NAME, return true
   if the identifier node is a valid attribute name for the string.  */

static inline bool
is_attribute_p (const char *attr_name, const_tree ident)
{
  return cmp_attribs (attr_name, strlen (attr_name),
		      IDENTIFIER_POINTER (ident), IDENTIFIER_LENGTH (ident));
}

/* Given an attribute name ATTR_NAME and a list of attributes LIST,
   return a pointer to the attribute's list element if the attribute
   is part of the list, or NULL_TREE if not found.  If the attribute
   appears more than once, this only returns the first occurrence; the
   TREE_CHAIN of the return value should be passed back in if further
   occurrences are wanted.  ATTR_NAME must be in the form 'text' (not
   '__text__').  */

static inline tree
lookup_attribute (const char *attr_name, tree list)
{
  gcc_checking_assert (attr_name[0] != '_');
  /* In most cases, list is NULL_TREE.  */
  if (list == NULL_TREE)
    return NULL_TREE;
  else
    {
      size_t attr_len = strlen (attr_name);
      /* Do the strlen() before calling the out-of-line implementation.
	 In most cases attr_name is a string constant, and the compiler
	 will optimize the strlen() away.  */
      return private_lookup_attribute (attr_name, attr_len, list);
    }
}

/* Given an attribute name ATTR_NAME and a list of attributes LIST,
   return a pointer to the attribute's list first element if the attribute
   starts with ATTR_NAME.  ATTR_NAME must be in the form 'text' (not
   '__text__').  */

static inline tree
lookup_attribute_by_prefix (const char *attr_name, tree list)
{
  gcc_checking_assert (attr_name[0] != '_');
  /* In most cases, list is NULL_TREE.  */
  if (list == NULL_TREE)
    return NULL_TREE;
  else
    {
      size_t attr_len = strlen (attr_name);
      while (list)
	{
	  size_t ident_len = IDENTIFIER_LENGTH (get_attribute_name (list));

	  if (attr_len > ident_len)
	    {
	      list = TREE_CHAIN (list);
	      continue;
	    }

	  const char *p = IDENTIFIER_POINTER (get_attribute_name (list));
	  gcc_checking_assert (attr_len == 0 || p[0] != '_');

	  if (strncmp (attr_name, p, attr_len) == 0)
	    break;

	  list = TREE_CHAIN (list);
	}

      return list;
    }
}

#endif // GCC_ATTRIBS_H