mcstreamerize .file and .file.  This also fixes an issue where the
normal form of .file would fail if the filename had a weird character
in it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94437 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index 1d2b778..151cf28 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -58,6 +58,8 @@
     virtual void EmitValueToOffset(const MCExpr *Offset,
                                    unsigned char Value = 0) {}
     
+    virtual void EmitFileDirective(StringRef Filename) {}
+    virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) {}
     virtual void EmitInstruction(const MCInst &Inst) {}
 
     virtual void Finish() {}