diff --git a/clang/include/clang/Serialization/ASTReader.h b/clang/include/clang/Serialization/ASTReader.h
--- a/clang/include/clang/Serialization/ASTReader.h
+++ b/clang/include/clang/Serialization/ASTReader.h
@@ -1355,7 +1355,7 @@
                           unsigned PreviousGeneration = 0);
 
   RecordLocation getLocalBitOffset(uint64_t GlobalOffset);
-  uint64_t getGlobalBitOffset(ModuleFile &M, uint32_t LocalOffset);
+  uint64_t getGlobalBitOffset(ModuleFile &M, uint64_t LocalOffset);
 
   /// Returns the first preprocessed entity ID that begins or ends after
   /// \arg Loc.
diff --git a/clang/include/clang/Serialization/ASTRecordReader.h b/clang/include/clang/Serialization/ASTRecordReader.h
--- a/clang/include/clang/Serialization/ASTRecordReader.h
+++ b/clang/include/clang/Serialization/ASTRecordReader.h
@@ -119,7 +119,7 @@
   //readExceptionSpecInfo(SmallVectorImpl<QualType> &ExceptionStorage);
 
   /// Get the global offset corresponding to a local offset.
-  uint64_t getGlobalBitOffset(uint32_t LocalOffset) {
+  uint64_t getGlobalBitOffset(uint64_t LocalOffset) {
     return Reader->getGlobalBitOffset(*F, LocalOffset);
   }
 
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -2879,7 +2879,7 @@
   return RecordLocation(I->second, GlobalOffset - I->second->GlobalBitOffset);
 }
 
-uint64_t ASTReader::getGlobalBitOffset(ModuleFile &M, uint32_t LocalOffset) {
+uint64_t ASTReader::getGlobalBitOffset(ModuleFile &M, uint64_t LocalOffset) {
   return LocalOffset + M.GlobalBitOffset;
 }