gcc/attribs.h

   1 /* Declarations and definitions dealing with attribute handling.
   2    Copyright (C) 2013-2017 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_ATTRIBS_H
  21 #define GCC_ATTRIBS_H
  22
  23 extern const struct attribute_spec *lookup_attribute_spec (const_tree);
  24 extern void init_attributes (void);
  25
  26 /* Process the attributes listed in ATTRIBUTES and install them in *NODE,
  27    which is either a DECL (including a TYPE_DECL) or a TYPE.  If a DECL,
  28    it should be modified in place; if a TYPE, a copy should be created
  29    unless ATTR_FLAG_TYPE_IN_PLACE is set in FLAGS.  FLAGS gives further
  30    information, in the form of a bitwise OR of flags in enum attribute_flags
  31    from tree.h.  Depending on these flags, some attributes may be
  32    returned to be applied at a later stage (for example, to apply
  33    a decl attribute to the declaration rather than to its type).  */
  34 extern tree decl_attributes (tree *, tree, int);
  35
  36 extern bool cxx11_attribute_p (const_tree);
  37 extern tree get_attribute_name (const_tree);
  38 extern void apply_tm_attr (tree, tree);
  39 extern tree make_attribute (const char *, const char *, tree);
  40
  41 extern struct scoped_attributes* register_scoped_attributes (const struct attribute_spec *,
  42                                                              const char *);
  43
  44 extern char *sorted_attr_string (tree);
  45 extern bool common_function_versions (tree, tree);
  46 extern char *make_unique_name (tree, const char *, bool);
  47 extern tree make_dispatcher_decl (const tree);
  48 extern bool is_function_default_version (const tree);
  49
  50 /* Return a type like TTYPE except that its TYPE_ATTRIBUTES
  51    is ATTRIBUTE.
  52
  53    Such modified types already made are recorded so that duplicates
  54    are not made.  */
  55
  56 extern tree build_type_attribute_variant (tree, tree);
  57 extern tree build_decl_attribute_variant (tree, tree);
  58 extern tree build_type_attribute_qual_variant (tree, tree, int);
  59
  60 extern bool attribute_value_equal (const_tree, const_tree);
  61
  62 /* Return 0 if the attributes for two types are incompatible, 1 if they
  63    are compatible, and 2 if they are nearly compatible (which causes a
  64    warning to be generated).  */
  65 extern int comp_type_attributes (const_tree, const_tree);
  66
  67 /* Default versions of target-overridable functions.  */
  68 extern tree merge_decl_attributes (tree, tree);
  69 extern tree merge_type_attributes (tree, tree);
  70
  71 /* Remove any instances of attribute ATTR_NAME in LIST and return the
  72    modified list.  */
  73
  74 extern tree remove_attribute (const char *, tree);
  75
  76 /* Given two attributes lists, return a list of their union.  */
  77
  78 extern tree merge_attributes (tree, tree);
  79
  80 /* Given two Windows decl attributes lists, possibly including
  81    dllimport, return a list of their union .  */
  82 extern tree merge_dllimport_decl_attributes (tree, tree);
  83
  84 /* Handle a "dllimport" or "dllexport" attribute.  */
  85 extern tree handle_dll_attribute (tree *, tree, tree, int, bool *);
  86
  87 extern int attribute_list_equal (const_tree, const_tree);
  88 extern int attribute_list_contained (const_tree, const_tree);
  89
  90 /* For a given IDENTIFIER_NODE, strip leading and trailing '_' characters
  91    so that we have a canonical form of attribute names.  */
  92
  93 static inline tree
  94 canonicalize_attr_name (tree attr_name)
  95 {
  96   const size_t l = IDENTIFIER_LENGTH (attr_name);
  97   const char *s = IDENTIFIER_POINTER (attr_name);
  98
  99   if (l > 4 && s[0] == '_' && s[1] == '_' && s[l - 1] == '_' && s[l - 2] == '_')
 100     return get_identifier_with_length (s + 2, l - 4);
 101
 102   return attr_name;
 103 }
 104
 105 /* Compare attribute identifiers ATTR1 and ATTR2 with length ATTR1_LEN and
 106    ATTR2_LEN.  */
 107
 108 static inline bool
 109 cmp_attribs (const char *attr1, size_t attr1_len,
 110              const char *attr2, size_t attr2_len)
 111 {
 112   return attr1_len == attr2_len && strncmp (attr1, attr2, attr1_len) == 0;
 113 }
 114
 115 /* Compare attribute identifiers ATTR1 and ATTR2.  */
 116
 117 static inline bool
 118 cmp_attribs (const char *attr1, const char *attr2)
 119 {
 120   return cmp_attribs (attr1, strlen (attr1), attr2, strlen (attr2));
 121 }
 122
 123 /* Given an identifier node IDENT and a string ATTR_NAME, return true
 124    if the identifier node is a valid attribute name for the string.  */
 125
 126 static inline bool
 127 is_attribute_p (const char *attr_name, const_tree ident)
 128 {
 129   return cmp_attribs (attr_name, strlen (attr_name),
 130                       IDENTIFIER_POINTER (ident), IDENTIFIER_LENGTH (ident));
 131 }
 132
 133 /* Given an attribute name ATTR_NAME and a list of attributes LIST,
 134    return a pointer to the attribute's list element if the attribute
 135    is part of the list, or NULL_TREE if not found.  If the attribute
 136    appears more than once, this only returns the first occurrence; the
 137    TREE_CHAIN of the return value should be passed back in if further
 138    occurrences are wanted.  ATTR_NAME must be in the form 'text' (not
 139    '__text__').  */
 140
 141 static inline tree
 142 lookup_attribute (const char *attr_name, tree list)
 143 {
 144   gcc_checking_assert (attr_name[0] != '_');
 145   /* In most cases, list is NULL_TREE.  */
 146   if (list == NULL_TREE)
 147     return NULL_TREE;
 148   else
 149     {
 150       size_t attr_len = strlen (attr_name);
 151       /* Do the strlen() before calling the out-of-line implementation.
 152          In most cases attr_name is a string constant, and the compiler
 153          will optimize the strlen() away.  */
 154       while (list)
 155         {
 156           tree attr = get_attribute_name (list);
 157           size_t ident_len = IDENTIFIER_LENGTH (attr);
 158           if (cmp_attribs (attr_name, attr_len, IDENTIFIER_POINTER (attr),
 159                            ident_len))
 160             break;
 161           list = TREE_CHAIN (list);
 162         }
 163
 164       return list;
 165     }
 166 }
 167
 168 /* Given an attribute name ATTR_NAME and a list of attributes LIST,
 169    return a pointer to the attribute's list first element if the attribute
 170    starts with ATTR_NAME.  ATTR_NAME must be in the form 'text' (not
 171    '__text__').  */
 172
 173 static inline tree
 174 lookup_attribute_by_prefix (const char *attr_name, tree list)
 175 {
 176   gcc_checking_assert (attr_name[0] != '_');
 177   /* In most cases, list is NULL_TREE.  */
 178   if (list == NULL_TREE)
 179     return NULL_TREE;
 180   else
 181     {
 182       size_t attr_len = strlen (attr_name);
 183       while (list)
 184         {
 185           size_t ident_len = IDENTIFIER_LENGTH (get_attribute_name (list));
 186
 187           if (attr_len > ident_len)
 188             {
 189               list = TREE_CHAIN (list);
 190               continue;
 191             }
 192
 193           const char *p = IDENTIFIER_POINTER (get_attribute_name (list));
 194           gcc_checking_assert (attr_len == 0 || p[0] != '_');
 195
 196           if (strncmp (attr_name, p, attr_len) == 0)
 197             break;
 198
 199           list = TREE_CHAIN (list);
 200         }
 201
 202       return list;
 203     }
 204 }
 205
 206 #endif // GCC_ATTRIBS_H