--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,100 @@
+//===--- CreateInvocationFromCommandLine.cpp - CompilerInvocation from Args ==//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Construct a compiler invocation object for command line driver arguments
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/Utils.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/Action.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/Tool.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/Host.h"
+using namespace clang;
+using namespace llvm::opt;
+
+std::unique_ptr<CompilerInvocation> clang::createInvocationFromCommandLine(
+    ArrayRef<const char *> ArgList, IntrusiveRefCntPtr<DiagnosticsEngine> Diags,
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS, bool ShouldRecoverOnErorrs,
+    std::vector<std::string> *CC1Args) {
+  if (!Diags.get()) {
+    // No diagnostics engine was provided, so create our own diagnostics object
+    // with the default options.
+    Diags = CompilerInstance::createDiagnostics(new DiagnosticOptions);
+  }
+
+  SmallVector<const char *, 16> Args(ArgList.begin(), ArgList.end());
+
+  // FIXME: Find a cleaner way to force the driver into restricted modes.
+  Args.push_back("-fsyntax-only");
+
+  // FIXME: We shouldn't have to pass in the path info.
+  driver::Driver TheDriver(Args[0], llvm::sys::getDefaultTargetTriple(),
+                           *Diags, VFS);
+
+  // Don't check that inputs exist, they may have been remapped.
+  TheDriver.setCheckInputsExist(false);
+
+  std::unique_ptr<driver::Compilation> C(TheDriver.BuildCompilation(Args));
+  if (!C)
+    return nullptr;
+
+  // Just print the cc1 options if -### was present.
+  if (C->getArgs().hasArg(driver::options::OPT__HASH_HASH_HASH)) {
+    C->getJobs().Print(llvm::errs(), "\n", true);
+    return nullptr;
+  }
+
+  // We expect to get back exactly one command job, if we didn't something
+  // failed. Offload compilation is an exception as it creates multiple jobs. If
+  // that's the case, we proceed with the first job. If caller needs a
+  // particular job, it should be controlled via options (e.g.
+  // --cuda-{host|device}-only for CUDA) passed to the driver.
+  const driver::JobList &Jobs = C->getJobs();
+  bool OffloadCompilation = false;
+  if (Jobs.size() > 1) {
+    for (auto &A : C->getActions()){
+      // On MacOSX real actions may end up being wrapped in BindArchAction
+      if (isa<driver::BindArchAction>(A))
+        A = *A->input_begin();
+      if (isa<driver::OffloadAction>(A)) {
+        OffloadCompilation = true;
+        break;
+      }
+    }
+  }
+  if (Jobs.size() == 0 || !isa<driver::Command>(*Jobs.begin()) ||
+      (Jobs.size() > 1 && !OffloadCompilation)) {
+    SmallString<256> Msg;
+    llvm::raw_svector_ostream OS(Msg);
+    Jobs.Print(OS, "; ", true);
+    Diags->Report(diag::err_fe_expected_compiler_job) << OS.str();
+    return nullptr;
+  }
+
+  const driver::Command &Cmd = cast<driver::Command>(*Jobs.begin());
+  if (StringRef(Cmd.getCreator().getName()) != "clang") {
+    Diags->Report(diag::err_fe_expected_clang_command);
+    return nullptr;
+  }
+
+  const ArgStringList &CCArgs = Cmd.getArguments();
+  if (CC1Args)
+    *CC1Args = {CCArgs.begin(), CCArgs.end()};
+  auto CI = std::make_unique<CompilerInvocation>();
+  if (!CompilerInvocation::CreateFromArgs(*CI, CCArgs, *Diags) &&
+      !ShouldRecoverOnErorrs)
+    return nullptr;
+  return CI;
+}