--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/lib/Support/Program.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,82 @@
+//===-- Program.cpp - Implement OS Program Concept --------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the operating system Program concept.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Program.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Config/llvm-config.h"
+#include <system_error>
+using namespace llvm;
+using namespace sys;
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only TRULY operating system
+//===          independent code.
+//===----------------------------------------------------------------------===//
+
+static bool Execute(ProcessInfo &PI, StringRef Program,
+                    ArrayRef<StringRef> Args, Optional<ArrayRef<StringRef>> Env,
+                    ArrayRef<Optional<StringRef>> Redirects,
+                    unsigned MemoryLimit, std::string *ErrMsg);
+
+int sys::ExecuteAndWait(StringRef Program, ArrayRef<StringRef> Args,
+                        Optional<ArrayRef<StringRef>> Env,
+                        ArrayRef<Optional<StringRef>> Redirects,
+                        unsigned SecondsToWait, unsigned MemoryLimit,
+                        std::string *ErrMsg, bool *ExecutionFailed) {
+  assert(Redirects.empty() || Redirects.size() == 3);
+  ProcessInfo PI;
+  if (Execute(PI, Program, Args, Env, Redirects, MemoryLimit, ErrMsg)) {
+    if (ExecutionFailed)
+      *ExecutionFailed = false;
+    ProcessInfo Result = Wait(
+        PI, SecondsToWait, /*WaitUntilTerminates=*/SecondsToWait == 0, ErrMsg);
+    return Result.ReturnCode;
+  }
+
+  if (ExecutionFailed)
+    *ExecutionFailed = true;
+
+  return -1;
+}
+
+ProcessInfo sys::ExecuteNoWait(StringRef Program, ArrayRef<StringRef> Args,
+                               Optional<ArrayRef<StringRef>> Env,
+                               ArrayRef<Optional<StringRef>> Redirects,
+                               unsigned MemoryLimit, std::string *ErrMsg,
+                               bool *ExecutionFailed) {
+  assert(Redirects.empty() || Redirects.size() == 3);
+  ProcessInfo PI;
+  if (ExecutionFailed)
+    *ExecutionFailed = false;
+  if (!Execute(PI, Program, Args, Env, Redirects, MemoryLimit, ErrMsg))
+    if (ExecutionFailed)
+      *ExecutionFailed = true;
+
+  return PI;
+}
+
+bool sys::commandLineFitsWithinSystemLimits(StringRef Program,
+                                            ArrayRef<const char *> Args) {
+  SmallVector<StringRef, 8> StringRefArgs;
+  StringRefArgs.reserve(Args.size());
+  for (const char *A : Args)
+    StringRefArgs.emplace_back(A);
+  return commandLineFitsWithinSystemLimits(Program, StringRefArgs);
+}
+
+// Include the platform-specific parts of this class.
+#ifdef LLVM_ON_UNIX
+#include "Unix/Program.inc"
+#endif
+#ifdef _WIN32
+#include "Windows/Program.inc"
+#endif