COFF: Add some error checking to SymbolTable::addCombinedLTOObject().

llvm-svn: 240511
diff --git a/lld/COFF/SymbolTable.cpp b/lld/COFF/SymbolTable.cpp
index ba714c2..2bd2538 100644
--- a/lld/COFF/SymbolTable.cpp
+++ b/lld/COFF/SymbolTable.cpp
@@ -287,7 +287,8 @@
     // We may see new references to runtime library symbols such as __chkstk
     // here. These symbols must be wholly defined in non-bitcode files.
     if (auto *B = dyn_cast<Lazy>(Sym->Body))
-      addMemberFile(B);
+      if (auto EC = addMemberFile(B))
+        return EC;
   }
 
   size_t NumBitcodeFiles = BitcodeFiles.size();