Return a MCSection from MCFragment::getParent().

Another step in merging MCSectionData and MCSection.

llvm-svn: 238162
diff --git a/llvm/lib/MC/MCExpr.cpp b/llvm/lib/MC/MCExpr.cpp
index b2c6965..47a1efe 100644
--- a/llvm/lib/MC/MCExpr.cpp
+++ b/llvm/lib/MC/MCExpr.cpp
@@ -491,8 +491,8 @@
   if (!Layout)
     return;
 
-  const MCSectionData &SecA = *AD.getFragment()->getParent();
-  const MCSectionData &SecB = *BD.getFragment()->getParent();
+  const MCSection &SecA = *AD.getFragment()->getParent();
+  const MCSection &SecB = *BD.getFragment()->getParent();
 
   if ((&SecA != &SecB) && !Addrs)
     return;
@@ -501,7 +501,8 @@
   Addend += Layout->getSymbolOffset(A->getSymbol()) -
             Layout->getSymbolOffset(B->getSymbol());
   if (Addrs && (&SecA != &SecB))
-    Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
+    Addend += (Addrs->lookup(&SecA.getSectionData()) -
+               Addrs->lookup(&SecB.getSectionData()));
 
   // Pointers to Thumb symbols need to have their low-bit set to allow
   // for interworking.