This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

RFA: PATCH to add chain lookup by index


It seems odd to me that this function didn't already exist, am I missing something? I want to use it for a C++ patch which will follow once this is in.

Tested x86_64-pc-linux-gnu. OK?
commit c72cdc4d6d659121d8171f5f2bedd3c27b7a54e0
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Sep 10 17:05:45 2009 -0400

    	* tree.c (chain_index): New fn.
    	* tree.h: Declare it.

diff --git a/gcc/tree.c b/gcc/tree.c
index 2f0e03c..27ab46c 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -1905,6 +1905,17 @@ purpose_member (const_tree elem, tree list)
   return NULL_TREE;
 }
 
+/* Returns element number IDX (zero-origin) of chain CHAIN, or
+   NULL_TREE.  */
+
+tree
+chain_index (int idx, tree chain)
+{
+  for (; chain && idx > 0; --idx)
+    chain = TREE_CHAIN (chain);
+  return chain;
+}
+
 /* Return nonzero if ELEM is part of the chain CHAIN.  */
 
 int
diff --git a/gcc/tree.h b/gcc/tree.h
index 9881090..7b431af 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -3914,6 +3914,7 @@ extern bool range_in_array_bounds_p (tree);
 
 extern tree value_member (tree, tree);
 extern tree purpose_member (const_tree, tree);
+extern tree chain_index (int, tree);
 
 extern int attribute_list_equal (const_tree, const_tree);
 extern int attribute_list_contained (const_tree, const_tree);

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]