[llvm-jitlink] Use heterogenous lookups with std::map (NFC)

Author: kazutakahirata

llvm/tools/llvm-jitlink/llvm-jitlink.cpp

@@ -1201,7 +1201,7 @@ void Session::modifyPassConfig(const Triple &TT,
 }
 
 Expected<JITDylib *> Session::getOrLoadDynamicLibrary(StringRef LibPath) {
-  auto It = DynLibJDs.find(LibPath.str());
+  auto It = DynLibJDs.find(LibPath);
   if (It != DynLibJDs.end()) {
     return It->second;
   }

llvm/tools/llvm-jitlink/llvm-jitlink.h

@@ -65,7 +65,7 @@ struct Session {
                                  GetSymbolTargetFunction GetSymbolTarget);
   };
 
-  using DynLibJDMap = std::map<std::string, orc::JITDylib *>;
+  using DynLibJDMap = std::map<std::string, orc::JITDylib *, std::less<>>;
   using SymbolInfoMap = StringMap<MemoryRegionInfo>;
   using FileInfoMap = StringMap<FileInfo>;