2 files changed, 18 insertions, 11 deletions

diff --git a/llvm/include/llvm/Bitcode/BitcodeWriterPass.h b/llvm/include/llvm/Bitcode/BitcodeWriterPass.h
index a4521bfc563..dd0d5771196 100644
--- a/llvm/include/llvm/Bitcode/BitcodeWriterPass.h
+++ b/llvm/include/llvm/Bitcode/BitcodeWriterPass.h
@@ -30,11 +30,15 @@ class PreservedAnalyses;
 /// If \c ShouldPreserveUseListOrder, encode use-list order so it can be
 /// reproduced when deserialized.
 ///
-/// If \c EmitSummaryIndex, emit the summary index (currently
-/// for use in ThinLTO optimization).
+/// If \c EmitSummaryIndex, emit the summary index (currently for use in ThinLTO
+/// optimization).
+///
+/// If \c EmitModuleHash, compute and emit the module hash in the bitcode
+/// (currently for use in ThinLTO incremental build).
 ModulePass *createBitcodeWriterPass(raw_ostream &Str,
                                     bool ShouldPreserveUseListOrder = false,
-                                    bool EmitSummaryIndex = false);
+                                    bool EmitSummaryIndex = false,
+                                    bool EmitModuleHash = false);
 
 /// \brief Pass for writing a module of IR out to a bitcode file.
 ///
@@ -44,6 +48,7 @@ class BitcodeWriterPass {
   raw_ostream &OS;
   bool ShouldPreserveUseListOrder;
   bool EmitSummaryIndex;
+  bool EmitModuleHash;
 
 public:
   /// \brief Construct a bitcode writer pass around a particular output stream.
@@ -55,9 +60,10 @@ public:
   /// for use in ThinLTO optimization).
   explicit BitcodeWriterPass(raw_ostream &OS,
                              bool ShouldPreserveUseListOrder = false,
-                             bool EmitSummaryIndex = false)
+                             bool EmitSummaryIndex = false,
+                             bool EmitModuleHash = false)
       : OS(OS), ShouldPreserveUseListOrder(ShouldPreserveUseListOrder),
-        EmitSummaryIndex(EmitSummaryIndex) {}
+  EmitSummaryIndex(EmitSummaryIndex), EmitModuleHash(EmitModuleHash) {}
 
   /// \brief Run the bitcode writer pass, and output the module to the selected
   /// output stream.
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriterPass.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriterPass.cpp
index 85b9bd83c13..7dbede4a847 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriterPass.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriterPass.cpp
@@ -19,7 +19,7 @@
 using namespace llvm;
 
 PreservedAnalyses BitcodeWriterPass::run(Module &M) {
-  WriteBitcodeToFile(&M, OS, ShouldPreserveUseListOrder, EmitSummaryIndex);
+  WriteBitcodeToFile(&M, OS, ShouldPreserveUseListOrder, EmitSummaryIndex, EmitModuleHash);
   return PreservedAnalyses::all();
 }
 
@@ -28,19 +28,20 @@ namespace {
     raw_ostream &OS; // raw_ostream to print on
     bool ShouldPreserveUseListOrder;
     bool EmitSummaryIndex;
+    bool EmitModuleHash;
 
   public:
     static char ID; // Pass identification, replacement for typeid
     explicit WriteBitcodePass(raw_ostream &o, bool ShouldPreserveUseListOrder,
-                              bool EmitSummaryIndex)
+                              bool EmitSummaryIndex, bool EmitModuleHash)
         : ModulePass(ID), OS(o),
           ShouldPreserveUseListOrder(ShouldPreserveUseListOrder),
-          EmitSummaryIndex(EmitSummaryIndex) {}
+          EmitSummaryIndex(EmitSummaryIndex), EmitModuleHash(EmitModuleHash) {}
 
     const char *getPassName() const override { return "Bitcode Writer"; }
 
     bool runOnModule(Module &M) override {
-      WriteBitcodeToFile(&M, OS, ShouldPreserveUseListOrder, EmitSummaryIndex);
+      WriteBitcodeToFile(&M, OS, ShouldPreserveUseListOrder, EmitSummaryIndex, EmitModuleHash);
       return false;
     }
   };
@@ -50,7 +51,7 @@ char WriteBitcodePass::ID = 0;
 
 ModulePass *llvm::createBitcodeWriterPass(raw_ostream &Str,
                                           bool ShouldPreserveUseListOrder,
-                                          bool EmitSummaryIndex) {
+                                          bool EmitSummaryIndex, bool EmitModuleHash) {
   return new WriteBitcodePass(Str, ShouldPreserveUseListOrder,
-                              EmitSummaryIndex);
+                              EmitSummaryIndex, EmitModuleHash);
 }