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 /* The backbone of lookup_attribute().  ATTR_LEN is the string length
  91    of ATTR_NAME, and LIST is not NULL_TREE.
  92
  93    The function is called from lookup_attribute in order to optimize
  94    for size.  */
  95 extern tree private_lookup_attribute (const char *attr_name, size_t attr_len,
  96                                       tree list);
  97
  98 /* For a given IDENTIFIER_NODE, strip leading and trailing '_' characters
  99    so that we have a canonical form of attribute names.  */
 100
 101 static inline tree
 102 canonicalize_attr_name (tree attr_name)
 103 {
 104   const size_t l = IDENTIFIER_LENGTH (attr_name);
 105   const char *s = IDENTIFIER_POINTER (attr_name);
 106
 107   if (l > 4 && s[0] == '_' && s[1] == '_' && s[l - 1] == '_' && s[l - 2] == '_')
 108     return get_identifier_with_length (s + 2, l - 4);
 109
 110   return attr_name;
 111 }
 112
 113 /* Compare attribute identifiers ATTR1 and ATTR2 with length ATTR1_LEN and
 114    ATTR2_LEN.  */
 115
 116 static inline bool
 117 cmp_attribs (const char *attr1, size_t attr1_len,
 118              const char *attr2, size_t attr2_len)
 119 {
 120   return attr1_len == attr2_len && strncmp (attr1, attr2, attr1_len) == 0;
 121 }
 122
 123 /* Compare attribute identifiers ATTR1 and ATTR2.  */
 124
 125 static inline bool
 126 cmp_attribs (const char *attr1, const char *attr2)
 127 {
 128   return cmp_attribs (attr1, strlen (attr1), attr2, strlen (attr2));
 129 }
 130
 131 /* Given an identifier node IDENT and a string ATTR_NAME, return true
 132    if the identifier node is a valid attribute name for the string.  */
 133
 134 static inline bool
 135 is_attribute_p (const char *attr_name, const_tree ident)
 136 {
 137   return cmp_attribs (attr_name, strlen (attr_name),
 138                       IDENTIFIER_POINTER (ident), IDENTIFIER_LENGTH (ident));
 139 }
 140
 141 /* Given an attribute name ATTR_NAME and a list of attributes LIST,
 142    return a pointer to the attribute's list element if the attribute
 143    is part of the list, or NULL_TREE if not found.  If the attribute
 144    appears more than once, this only returns the first occurrence; the
 145    TREE_CHAIN of the return value should be passed back in if further
 146    occurrences are wanted.  ATTR_NAME must be in the form 'text' (not
 147    '__text__').  */
 148
 149 static inline tree
 150 lookup_attribute (const char *attr_name, tree list)
 151 {
 152   gcc_checking_assert (attr_name[0] != '_');
 153   /* In most cases, list is NULL_TREE.  */
 154   if (list == NULL_TREE)
 155     return NULL_TREE;
 156   else
 157     {
 158       size_t attr_len = strlen (attr_name);
 159       /* Do the strlen() before calling the out-of-line implementation.
 160          In most cases attr_name is a string constant, and the compiler
 161          will optimize the strlen() away.  */
 162       return private_lookup_attribute (attr_name, attr_len, list);
 163     }
 164 }
 165
 166 /* Given an attribute name ATTR_NAME and a list of attributes LIST,
 167    return a pointer to the attribute's list first element if the attribute
 168    starts with ATTR_NAME.  ATTR_NAME must be in the form 'text' (not
 169    '__text__').  */
 170
 171 static inline tree
 172 lookup_attribute_by_prefix (const char *attr_name, tree list)
 173 {
 174   gcc_checking_assert (attr_name[0] != '_');
 175   /* In most cases, list is NULL_TREE.  */
 176   if (list == NULL_TREE)
 177     return NULL_TREE;
 178   else
 179     {
 180       size_t attr_len = strlen (attr_name);
 181       while (list)
 182         {
 183           size_t ident_len = IDENTIFIER_LENGTH (get_attribute_name (list));
 184
 185           if (attr_len > ident_len)
 186             {
 187               list = TREE_CHAIN (list);
 188               continue;
 189             }
 190
 191           const char *p = IDENTIFIER_POINTER (get_attribute_name (list));
 192           gcc_checking_assert (attr_len == 0 || p[0] != '_');
 193
 194           if (strncmp (attr_name, p, attr_len) == 0)
 195             break;
 196
 197           list = TREE_CHAIN (list);
 198         }
 199
 200       return list;
 201     }
 202 }
 203
 204 #endif // GCC_ATTRIBS_H