1 files changed, 17 insertions, 2 deletions
diff --git a/include/llvm/Bitcode/BitcodeWriter.h b/include/llvm/Bitcode/BitcodeWriter.h
index 4f72f98bbf9c..271cb2d81bbb 100644
--- a/include/llvm/Bitcode/BitcodeWriter.h
+++ b/include/llvm/Bitcode/BitcodeWriter.h
@@ -43,9 +43,16 @@ namespace llvm {
     ///
     /// \p GenerateHash enables hashing the Module and including the hash in the
     /// bitcode (currently for use in ThinLTO incremental build).
+    ///
+    /// If \p ModHash is non-null, when GenerateHash is true, the resulting
+    /// hash is written into ModHash. When GenerateHash is false, that value
+    /// is used as the hash instead of computing from the generated bitcode.
+    /// Can be used to produce the same module hash for a minimized bitcode
+    /// used just for the thin link as in the regular full bitcode that will
+    /// be used in the backend.
     void writeModule(const Module *M, bool ShouldPreserveUseListOrder = false,
                      const ModuleSummaryIndex *Index = nullptr,
-                     bool GenerateHash = false);
+                     bool GenerateHash = false, ModuleHash *ModHash = nullptr);
   };
 
   /// \brief Write the specified module to the specified raw output stream.
@@ -62,10 +69,18 @@ namespace llvm {
   ///
   /// \p GenerateHash enables hashing the Module and including the hash in the
   /// bitcode (currently for use in ThinLTO incremental build).
+  ///
+  /// If \p ModHash is non-null, when GenerateHash is true, the resulting
+  /// hash is written into ModHash. When GenerateHash is false, that value
+  /// is used as the hash instead of computing from the generated bitcode.
+  /// Can be used to produce the same module hash for a minimized bitcode
+  /// used just for the thin link as in the regular full bitcode that will
+  /// be used in the backend.
   void WriteBitcodeToFile(const Module *M, raw_ostream &Out,
                           bool ShouldPreserveUseListOrder = false,
                           const ModuleSummaryIndex *Index = nullptr,
-                          bool GenerateHash = false);
+                          bool GenerateHash = false,
+                          ModuleHash *ModHash = nullptr);
 
   /// Write the specified module summary index to the given raw output stream,
   /// where it will be written in a new bitcode block. This is used when