builtin-attrs.def: Add comments.

gcc/ChangeLog:

	* builtin-attrs.def: Add comments.

From-SVN: r251101

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5902989dcd770e987275e96529a6910e583253db..2cd7917164ffcc7e4cd24f1c0c47368db0b713cc 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2017-08-14  Martin Sebor  <msebor@redhat.com>
+
+       * builtin-attrs.def: Add comments.
+
 2017-08-14  Martin Sebor  <msebor@redhat.com>
 
        PR c/81117

diff --git a/gcc/builtin-attrs.def b/gcc/builtin-attrs.def
index 53e67e62844af99fa5f8460e771277b286294119..336fd73e777b36b70907a99621bdce0442fe878d 100644 (file)
--- a/gcc/builtin-attrs.def
+++ b/gcc/builtin-attrs.def
@@ -18,7 +18,10 @@ along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
 /* This header provides a declarative way of describing the attributes
-   that are applied to some functions by default.
+   that are applied to some built-in functions by default.  Attributes
+   that are meant to be used by user-defined functions but aren't used
+   by any built-ins, or attributes that apply to types or variables
+   but not to functions need not and should not be defined here.
 
    Before including this header, you must define the following macros.
    In each case where there is an ENUM, it is an identifier used to
@@ -85,7 +88,9 @@ DEF_LIST_INT_INT (5,0)
 DEF_LIST_INT_INT (5,6)
 #undef DEF_LIST_INT_INT
 
-/* Construct trees for identifiers.  */
+/* Construct trees for identifiers used in built-in function attributes.
+   The construction contributes to startup costs so only attributes that
+   are used to define built-ins should be defined here.  */
 DEF_ATTR_IDENT (ATTR_ALLOC_SIZE, "alloc_size")
 DEF_ATTR_IDENT (ATTR_COLD, "cold")
 DEF_ATTR_IDENT (ATTR_CONST, "const")