--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lldb/source/Host/common/MonitoringProcessLauncher.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,70 @@
+//===-- MonitoringProcessLauncher.cpp -------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Host/MonitoringProcessLauncher.h"
+#include "lldb/Host/FileSystem.h"
+#include "lldb/Host/HostProcess.h"
+#include "lldb/Host/ProcessLaunchInfo.h"
+#include "lldb/Utility/Log.h"
+
+#include "llvm/Support/FileSystem.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+MonitoringProcessLauncher::MonitoringProcessLauncher(
+    std::unique_ptr<ProcessLauncher> delegate_launcher)
+    : m_delegate_launcher(std::move(delegate_launcher)) {}
+
+HostProcess
+MonitoringProcessLauncher::LaunchProcess(const ProcessLaunchInfo &launch_info,
+                                         Status &error) {
+  ProcessLaunchInfo resolved_info(launch_info);
+
+  error.Clear();
+
+  FileSystem &fs = FileSystem::Instance();
+  FileSpec exe_spec(resolved_info.GetExecutableFile());
+
+  if (!fs.Exists(exe_spec))
+    FileSystem::Instance().Resolve(exe_spec);
+
+  if (!fs.Exists(exe_spec))
+    FileSystem::Instance().ResolveExecutableLocation(exe_spec);
+
+  if (!fs.Exists(exe_spec)) {
+    error.SetErrorStringWithFormatv("executable doesn't exist: '{0}'",
+                                    exe_spec);
+    return HostProcess();
+  }
+
+  resolved_info.SetExecutableFile(exe_spec, false);
+  assert(!resolved_info.GetFlags().Test(eLaunchFlagLaunchInTTY));
+
+  HostProcess process =
+      m_delegate_launcher->LaunchProcess(resolved_info, error);
+
+  if (process.GetProcessId() != LLDB_INVALID_PROCESS_ID) {
+    Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
+
+    assert(launch_info.GetMonitorProcessCallback());
+    llvm::Expected<HostThread> maybe_thread =
+        process.StartMonitoring(launch_info.GetMonitorProcessCallback(),
+                                launch_info.GetMonitorSignals());
+    if (!maybe_thread)
+      error.SetErrorStringWithFormatv("failed to launch host thread: {}",
+                                      llvm::toString(maybe_thread.takeError()));
+    if (log)
+      log->PutCString("started monitoring child process.");
+  } else {
+    // Invalid process ID, something didn't go well
+    if (error.Success())
+      error.SetErrorString("process launch failed for unknown reasons");
+  }
+  return process;
+}