New attribute lookup function addition

* tree.h (private_lookup_attribute_starting): New function.
	(lookup_attribute_starting): Likewise.
	* tree.c (private_lookup_attribute_starting): Likewise.

From-SVN: r211219

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2014-06-04  Martin Liska  <mliska@suse.cz>
+
+	* tree.h (private_lookup_attribute_starting): New function.
+	(lookup_attribute_starting): Likewise.
+	* tree.c (private_lookup_attribute_starting): Likewise.
+
 2014-06-04  Martin Liska  <mliska@suse.cz>
 
 	* cgraph.h (expand_thunk): New argument added.

gcc/tree.c

@@ -5759,6 +5759,44 @@ private_lookup_attribute (const char *attr_name, size_t attr_len, tree list)
   return 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__').  */
+
+tree
+private_lookup_attribute_by_prefix (const char *attr_name, size_t attr_len,
+				    tree list)
+{
+  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));
+
+      if (strncmp (attr_name, p, attr_len) == 0)
+	break;
+
+      /* TODO: If we made sure that attributes were stored in the
+	 canonical form without '__...__' (ie, as in 'text' as opposed
+	 to '__text__') then we could avoid the following case.  */
+      if (p[0] == '_' && p[1] == '_' &&
+	  strncmp (attr_name, p + 2, attr_len) == 0)
+	break;
+
+      list = TREE_CHAIN (list);
+    }
+
+  return list;
+}
+
+
 /* A variant of lookup_attribute() that can be used with an identifier
    as the first argument, and where the identifier can be either
    'text' or '__text__'.

gcc/tree.h

@@ -3736,6 +3736,10 @@ extern tree merge_type_attributes (tree, tree);
    and you should never call it directly.  */
 extern tree private_lookup_attribute (const char *, size_t, tree);
 
+/* This function is a private implementation detail
+   of lookup_attribute_by_prefix() and you should never call it directly.  */
+extern tree private_lookup_attribute_by_prefix (const char *, size_t, tree);
+
 /* 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
@@ -3758,6 +3762,24 @@ lookup_attribute (const char *attr_name, tree list)
     return private_lookup_attribute (attr_name, strlen (attr_name), 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
+    return private_lookup_attribute_by_prefix (attr_name, strlen (attr_name),
+					       list);
+}
+
+
 /* This function is a private implementation detail of
    is_attribute_p() and you should never call it directly.  */
 extern bool private_is_attribute_p (const char *, size_t, const_tree);