Correct comments.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61311 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/TranslationUnit.cpp b/lib/AST/TranslationUnit.cpp
index 826bfa0..adf6876 100644
--- a/lib/AST/TranslationUnit.cpp
+++ b/lib/AST/TranslationUnit.cpp
@@ -215,7 +215,7 @@
   // Emit ASTContext.
   Sezr.EnterBlock(ASTContextBlock);  
   Sezr.EmitOwnedPtr(Context);  
-  Sezr.ExitBlock();    
+  Sezr.ExitBlock();      // exit "ASTContextBlock"
   
   Sezr.EnterBlock(BasicMetadataBlock);
   
@@ -230,7 +230,7 @@
   Sezr.EmitPtr(&Context->Target);
   Sezr.EmitCStr(Context->Target.getTargetTriple());
   
-  Sezr.ExitBlock(); // exit "BasicMetadataBlock"
+  Sezr.ExitBlock(); // exit "SourceManager and Target Block"
   
   // Emit the Selectors.
   Sezr.Emit(Context->Selectors);
@@ -238,7 +238,7 @@
   // Emit the Identifier Table.
   Sezr.Emit(Context->Idents);
   
-  Sezr.ExitBlock();  // exit "ASTContextBlock"
+  Sezr.ExitBlock(); // exit "BasicMetadataBlock"
 }
 
 TranslationUnit*