Add SourceMgr to MCContext for backend diagnostics.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149090 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index a1a01e3..e22a5ab 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -28,8 +28,8 @@
 
 
 MCContext::MCContext(const MCAsmInfo &mai, const MCRegisterInfo &mri,
-                     const MCObjectFileInfo *mofi) :
-  MAI(mai), MRI(mri), MOFI(mofi),
+                     const MCObjectFileInfo *mofi, const SourceMgr *mgr) :
+  SrcMgr(mgr), MAI(mai), MRI(mri), MOFI(mofi),
   Allocator(), Symbols(Allocator), UsedNames(Allocator),
   NextUniqueID(0),
   CurrentDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0),