diff --git a/include/llvm/Analysis/DSNode.h b/include/llvm/Analysis/DSNode.h
index 74fd5afe532..12d2cbc2bd4 100644
--- a/include/llvm/Analysis/DSNode.h
+++ b/include/llvm/Analysis/DSNode.h
@@ -1,6 +1,6 @@
-//===- DSSupport.h - Support for datastructure graphs -----------*- C++ -*-===//
+//===- DSNode.h - Node definition for datastructure graphs ------*- C++ -*-===//
 //
-// Support for graph nodes, call sites, and types.
+// Data structure graph nodes and some implementation of DSNodeHandle.
 //
 //===----------------------------------------------------------------------===//
 
diff --git a/include/llvm/Analysis/DSSupport.h b/include/llvm/Analysis/DSSupport.h
index b3c3ed02965..ae1e815ba79 100644
--- a/include/llvm/Analysis/DSSupport.h
+++ b/include/llvm/Analysis/DSSupport.h
@@ -28,6 +28,10 @@ class DSNodeIterator;          // Data structure graph traversal iterator
 /// graph from getting out of date.  This class represents a "pointer" in the
 /// graph, whose destination is an indexed offset into a node.
 ///
+/// Note: some functions that are marked as inline in DSNodeHandle are actually
+/// defined in DSNode.h because they need knowledge of DSNode operation. Putting
+/// them in a CPP file wouldn't help making them inlined and keeping DSNode and
+/// DSNodeHandle (and friends) in one file complicates things.
 class DSNodeHandle {
   DSNode *N;
   unsigned Offset;
diff --git a/include/llvm/Analysis/DataStructure/DSNode.h b/include/llvm/Analysis/DataStructure/DSNode.h
index 74fd5afe532..12d2cbc2bd4 100644
--- a/include/llvm/Analysis/DataStructure/DSNode.h
+++ b/include/llvm/Analysis/DataStructure/DSNode.h
@@ -1,6 +1,6 @@
-//===- DSSupport.h - Support for datastructure graphs -----------*- C++ -*-===//
+//===- DSNode.h - Node definition for datastructure graphs ------*- C++ -*-===//
 //
-// Support for graph nodes, call sites, and types.
+// Data structure graph nodes and some implementation of DSNodeHandle.
 //
 //===----------------------------------------------------------------------===//
 
diff --git a/include/llvm/Analysis/DataStructure/DSSupport.h b/include/llvm/Analysis/DataStructure/DSSupport.h
index b3c3ed02965..ae1e815ba79 100644
--- a/include/llvm/Analysis/DataStructure/DSSupport.h
+++ b/include/llvm/Analysis/DataStructure/DSSupport.h
@@ -28,6 +28,10 @@ class DSNodeIterator;          // Data structure graph traversal iterator
 /// graph from getting out of date.  This class represents a "pointer" in the
 /// graph, whose destination is an indexed offset into a node.
 ///
+/// Note: some functions that are marked as inline in DSNodeHandle are actually
+/// defined in DSNode.h because they need knowledge of DSNode operation. Putting
+/// them in a CPP file wouldn't help making them inlined and keeping DSNode and
+/// DSNodeHandle (and friends) in one file complicates things.
 class DSNodeHandle {
   DSNode *N;
   unsigned Offset;