Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -3193,12 +3193,17 @@
   return false;
 }
 
-static void linkXRayRuntimeDeps(const ToolChain &TC, ArgStringList &CmdArgs) {
+static void linkXRayRuntimeDeps(const ToolChain &TC, const ArgList &Args,
+                                ArgStringList &CmdArgs) {
   CmdArgs.push_back("--no-as-needed");
   CmdArgs.push_back("-lpthread");
   CmdArgs.push_back("-lrt");
   CmdArgs.push_back("-lm");
   CmdArgs.push_back("-latomic");
+  if (TC.GetCXXStdlibType(Args) == ToolChain::CST_Libcxx)
+    CmdArgs.push_back("-lc++");
+  else
+    CmdArgs.push_back("-lstdc++");
   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD)
     CmdArgs.push_back("-ldl");
 }
@@ -4604,6 +4609,16 @@
 
   Args.AddAllArgs(CmdArgs, options::OPT_finstrument_functions);
 
+  if (Args.hasArg(options::OPT_fxray_instrument,
+                  options::OPT_fnoxray_instrument, false)) {
+    CmdArgs.push_back("-fxray-instrument");
+    if (Arg *A = Args.getLastArg(options::OPT_fxray_instruction_threshold_,
+                                 options::OPT_fxray_instruction_threshold_EQ)) {
+      CmdArgs.push_back("-fxray-instruction-threshold");
+      CmdArgs.push_back(A->getValue());
+    }
+  }
+
   if (Args.hasFlag(options::OPT_fxray_instrument,
                    options::OPT_fnoxray_instrument, false)) {
     CmdArgs.push_back("-fxray-instrument");
@@ -9451,7 +9466,7 @@
         linkSanitizerRuntimeDeps(ToolChain, CmdArgs);
 
       if (NeedsXRayDeps)
-        linkXRayRuntimeDeps(ToolChain, CmdArgs);
+        linkXRayRuntimeDeps(ToolChain, Args, CmdArgs);
 
       bool WantPthread = Args.hasArg(options::OPT_pthread) ||
                          Args.hasArg(options::OPT_pthreads);