MC/Mach-O: Explicitly track atoms, as represented by their defining symbol, for each fragment (not yet used).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103438 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 69afcc8..5c2bf78 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -133,17 +133,13 @@
   SD->FileSize = Value;
 }
 
-  /// @}
-
 /* *** */
 
 MCFragment::MCFragment() : Kind(FragmentType(~0)) {
 }
 
 MCFragment::MCFragment(FragmentType _Kind, MCSectionData *_Parent)
-  : Kind(_Kind),
-    Parent(_Parent),
-    EffectiveSize(~UINT64_C(0))
+  : Kind(_Kind), Parent(_Parent), Atom(0), EffectiveSize(~UINT64_C(0))
 {
   if (Parent)
     Parent->getFragmentList().push_back(this);