Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -601,6 +601,17 @@
   return Names.takeVector();
 }
 
+static void parseClangOption(StringRef Opt, const Twine &Msg) {
+  std::string Err;
+  raw_string_ostream OS(Err);
+
+  const char *Argv[] = {Config->ProgName.data(), Opt.data()};
+  if (cl::ParseCommandLineOptions(2, Argv, "", &OS))
+    return;
+  OS.flush();
+  error(Msg + ": " + StringRef(Err).trim());
+}
+
 // Initializes Config members by the command line options.
 void LinkerDriver::readConfigs(opt::InputArgList &Args) {
   errorHandler().Verbose = Args.hasArg(OPT_verbose);
@@ -709,7 +720,6 @@
   Config->ZWxneeded = hasZOption(Args, "wxneeded");
 
   // Parse LTO plugin-related options for compatibility with gold.
-  std::vector<const char *> LTOOptions({Config->ProgName.data()});
   for (auto *Arg : Args.filtered(OPT_plugin_opt)) {
     StringRef S = Arg->getValue();
     if (S == "disable-verify")
@@ -723,15 +733,15 @@
     else if (S.startswith("jobs="))
       Config->ThinLTOJobs = parseInt(S.substr(5), Arg);
     else if (S.startswith("mcpu="))
-      LTOOptions.push_back(Saver.save("-" + S).data());
+      parseClangOption(Saver.save("-" + S), Arg->getSpelling());
     else if (!S.startswith("/") && !S.startswith("-fresolution=") &&
              !S.startswith("-pass-through=") && !S.startswith("thinlto"))
-      LTOOptions.push_back(S.data());
+      parseClangOption(S, Arg->getSpelling());
   }
-  // Parse and evaluate -mllvm options.
+
+  // Parse -mllvm options.
   for (auto *Arg : Args.filtered(OPT_mllvm))
-    LTOOptions.push_back(Arg->getValue());
-  cl::ParseCommandLineOptions(LTOOptions.size(), LTOOptions.data());
+    parseClangOption(Arg->getValue(), Arg->getSpelling());
 
   if (Config->LTOO > 3)
     error("invalid optimization level for LTO: " + Twine(Config->LTOO));
Index: test/ELF/lto-plugin-ignore.s
===================================================================
--- test/ELF/lto-plugin-ignore.s
+++ test/ELF/lto-plugin-ignore.s
@@ -5,7 +5,6 @@
 # RUN:   -plugin-opt=-pass-through=-lgcc -plugin-opt=-function-sections \
 # RUN:   -plugin-opt=-data-sections -plugin-opt=thinlto -o /dev/null
 
-# RUN: not ld.lld %t -plugin-opt=-data-sectionxxx \
-# RUN:   -plugin-opt=-function-sectionxxx 2>&1 | FileCheck %s
-# CHECK: Unknown command line argument '-data-sectionxxx'
-# CHECK: Unknown command line argument '-function-sectionxxx'
+# RUN: not ld.lld %t -plugin-opt=-abc -plugin-opt=-xyz 2>&1 | FileCheck %s
+# CHECK: error: --plugin-opt: ld.lld: Unknown command line argument '-abc'
+# CHECK: error: --plugin-opt: ld.lld: Unknown command line argument '-xyz'