Rename PCHReader to ASTReader.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@111467 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/GeneratePCH.cpp b/lib/Serialization/GeneratePCH.cpp
index 6782bf8..ebc3c02 100644
--- a/lib/Serialization/GeneratePCH.cpp
+++ b/lib/Serialization/GeneratePCH.cpp
@@ -36,7 +36,7 @@
   // calls.
   StatCalls = new MemorizeStatCalls;
   // If we have a chain, we want new stat calls only, so install the memorizer
-  // *after* the already installed PCHReader's stat cache.
+  // *after* the already installed ASTReader's stat cache.
   PP.getFileManager().addStatCache(StatCalls,
     /*AtBeginning=*/!Chaining);
 }