[ORC] Remove an incorrect use of 'cantFail'.

This code was moved out from BasicObjectLayerMaterializationUnit, which required
the supplied object to be well formed. The getObjectSymbolFlags function does
not require a well-formed object, so we have to propagate the error here.

llvm-svn: 338975
diff --git a/llvm/lib/ExecutionEngine/Orc/Layer.cpp b/llvm/lib/ExecutionEngine/Orc/Layer.cpp
index 46b9e57..8ba88b2 100644
--- a/llvm/lib/ExecutionEngine/Orc/Layer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/Layer.cpp
@@ -116,8 +116,10 @@
   for (auto &Sym : (*Obj)->symbols()) {
     if (!(Sym.getFlags() & object::BasicSymbolRef::SF_Undefined) &&
         (Sym.getFlags() & object::BasicSymbolRef::SF_Exported)) {
-      auto InternedName =
-          ES.getSymbolStringPool().intern(cantFail(Sym.getName()));
+      auto Name = Sym.getName();
+      if (!Name)
+        return Name.takeError();
+      auto InternedName = ES.getSymbolStringPool().intern(*Name);
       auto SymFlags = JITSymbolFlags::fromObjectSymbol(Sym);
       if (!SymFlags)
         return SymFlags.takeError();