[Orc] Two small fixes in TPCDynamicLibrarySearchGenerator

There is one result per lookup symbol, so we have to advance the result iterator no matter whether it's NULL or not.
MissingSymbols variable is unused.

Reviewed By: lhames

Differential Revision: https://reviews.llvm.org/D91707

Author: weliveindetail

llvm/lib/ExecutionEngine/Orc/TPCDynamicLibrarySearchGenerator.cpp

@@ -50,12 +50,13 @@ Error TPCDynamicLibrarySearchGenerator::tryToGenerate(
   assert(Result->front().size() == LookupSymbols.size() &&
          "Result has incorrect number of elements");
 
-  SymbolNameVector MissingSymbols;
   auto ResultI = Result->front().begin();
-  for (auto &KV : LookupSymbols)
+  for (auto &KV : LookupSymbols) {
     if (*ResultI)
       NewSymbols[KV.first] =
-          JITEvaluatedSymbol(*ResultI++, JITSymbolFlags::Exported);
+          JITEvaluatedSymbol(*ResultI, JITSymbolFlags::Exported);
+    ResultI++;
+  }
 
   // If there were no resolved symbols bail out.
   if (NewSymbols.empty())