Cherry-pick r234714: [MC] Write padding into fragments when -mc-relax-all flag is used

include/llvm/MC/MCELFStreamer.h

Index: include/llvm/MC/MCELFStreamer.h
diff --git a/include/llvm/MC/MCELFStreamer.h b/include/llvm/MC/MCELFStreamer.h
index ab6c5e3d6124042ca63ec005b531090727b1d034..e9e85bc7a35ca1f4fb5a24405a32ffdb8503c38f 100644
--- a/include/llvm/MC/MCELFStreamer.h
+++ b/include/llvm/MC/MCELFStreamer.h
@@ -100,6 +100,9 @@ private:
 
   void fixSymbolsInTLSFixups(const MCExpr *expr);
 
+  /// \brief Merge the content of the fragment \p EF into the fragment \p DF.
+  void mergeFragment(MCDataFragment *, MCEncodedFragmentWithFixups *);
+
   bool SeenIdent;
 
   struct LocalCommon {
@@ -111,6 +114,10 @@ private:
   std::vector<LocalCommon> LocalCommons;
 
   SmallPtrSet<MCSymbol *, 16> BindingExplicitlySet;
+
+  /// BundleGroups - The stack of fragments holding the bundle-locked
+  /// instructions.
+  llvm::SmallVector<MCDataFragment *, 4> BundleGroups;
 };
 
 MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,