--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/lib/Driver/ToolChains/BareMetal.h	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,86 @@
+//===--- BareMetal.h - Bare Metal Tool and ToolChain -------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_BAREMETAL_H
+#define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_BAREMETAL_H
+
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+
+#include <string>
+
+namespace clang {
+namespace driver {
+
+namespace toolchains {
+
+class LLVM_LIBRARY_VISIBILITY BareMetal : public ToolChain {
+public:
+  BareMetal(const Driver &D, const llvm::Triple &Triple,
+            const llvm::opt::ArgList &Args);
+  ~BareMetal() override;
+
+  static bool handlesTarget(const llvm::Triple &Triple);
+protected:
+  Tool *buildLinker() const override;
+
+public:
+  bool useIntegratedAs() const override { return true; }
+  bool isCrossCompiling() const override { return true; }
+  bool isPICDefault() const override { return false; }
+  bool isPIEDefault() const override { return false; }
+  bool isPICDefaultForced() const override { return false; }
+  bool SupportsProfiling() const override { return false; }
+
+  RuntimeLibType GetDefaultRuntimeLibType() const override {
+    return ToolChain::RLT_CompilerRT;
+  }
+  CXXStdlibType GetDefaultCXXStdlibType() const override {
+    return ToolChain::CST_Libcxx;
+  }
+
+  const char *getDefaultLinker() const override { return "ld.lld"; }
+
+  std::string getRuntimesDir() const;
+  void AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
+                                 llvm::opt::ArgStringList &CC1Args) const override;
+  void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
+                             llvm::opt::ArgStringList &CC1Args,
+                             Action::OffloadKind DeviceOffloadKind) const override;
+  void AddClangCXXStdlibIncludeArgs(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
+  void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
+                           llvm::opt::ArgStringList &CmdArgs) const override;
+  void AddLinkRuntimeLib(const llvm::opt::ArgList &Args,
+                         llvm::opt::ArgStringList &CmdArgs) const;
+};
+
+} // namespace toolchains
+
+namespace tools {
+namespace baremetal {
+
+class LLVM_LIBRARY_VISIBILITY Linker : public Tool {
+public:
+  Linker(const ToolChain &TC) : Tool("baremetal::Linker", "ld.lld", TC) {}
+  bool isLinkJob() const override { return true; }
+  bool hasIntegratedCPP() const override { return false; }
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
+
+} // namespace baremetal
+} // namespace tools
+
+} // namespace driver
+} // namespace clang
+
+#endif