diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index 908aa4b070..97b4cfc028 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -387,8 +387,11 @@ namespace clang {
       /// for typo correction.
       KNOWN_NAMESPACES = 46,
 
-      /// \brief Record code for the source location remapping information.
-      SOURCE_LOCATION_MAP = 47,
+      /// \brief Record code for the remapping information used to relate
+      /// loaded modules to the various offsets and IDs(e.g., source location 
+      /// offests, declaration and type IDs) that are used in that module to
+      /// refer to other modules.
+      MODULE_OFFSET_MAP = 47,
 
       /// \brief Record code for the source manager line table information,
       /// which stores information about #line directives.
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index d8f6c6a640..6521e7c3bd 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2271,7 +2271,7 @@ ASTReader::ReadASTBlock(Module &F) {
       break;
     }
 
-    case SOURCE_LOCATION_MAP: {
+    case MODULE_OFFSET_MAP: {
       // Additional remapping information.
       const unsigned char *Data = (const unsigned char*)BlobStart;
       const unsigned char *DataEnd = Data + BlobLen;
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index e506bba8a2..649b05e21d 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -1582,7 +1582,7 @@ void ASTWriter::WriteSourceManagerBlock(SourceManager &SourceMgr,
     Chain->ModuleMgr.exportLookup(Modules);
 
     Abbrev = new BitCodeAbbrev();
-    Abbrev->Add(BitCodeAbbrevOp(SOURCE_LOCATION_MAP));
+    Abbrev->Add(BitCodeAbbrevOp(MODULE_OFFSET_MAP));
     Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
     unsigned SLocMapAbbrev = Stream.EmitAbbrev(Abbrev);
     llvm::SmallString<2048> Buffer;
@@ -1597,7 +1597,7 @@ void ASTWriter::WriteSourceManagerBlock(SourceManager &SourceMgr,
       }
     }
     Record.clear();
-    Record.push_back(SOURCE_LOCATION_MAP);
+    Record.push_back(MODULE_OFFSET_MAP);
     Stream.EmitRecordWithBlob(SLocMapAbbrev, Record,
                               Buffer.data(), Buffer.size());
   }