diff --git a/lib/Frontend/CreateInvocationFromCommandLine.cpp b/lib/Frontend/CreateInvocationFromCommandLine.cpp
new file mode 100644
index 0000000..0005f91
--- /dev/null
+++ b/lib/Frontend/CreateInvocationFromCommandLine.cpp
@@ -0,0 +1,90 @@
+//===--- CreateInvocationFromCommandLine.cpp - CompilerInvocation from Args ==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Construct a compiler invocation object for command line driver arguments
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/Utils.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/DiagnosticOptions.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/ArgList.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/Tool.h"
+#include "llvm/Support/Host.h"
+using namespace clang;
+
+/// createInvocationFromCommandLine - Construct a compiler invocation object for
+/// a command line argument vector.
+///
+/// \return A CompilerInvocation, or 0 if none was built for the given
+/// argument vector.
+CompilerInvocation *
+clang::createInvocationFromCommandLine(llvm::ArrayRef<const char *> ArgList,
+                                   llvm::IntrusiveRefCntPtr<Diagnostic> Diags) {
+  if (!Diags.getPtr()) {
+    // No diagnostics engine was provided, so create our own diagnostics object
+    // with the default options.
+    DiagnosticOptions DiagOpts;
+    Diags = CompilerInstance::createDiagnostics(DiagOpts, ArgList.size(),
+                                                ArgList.begin());
+  }
+
+  llvm::SmallVector<const char *, 16> Args;
+  Args.push_back("<clang>"); // FIXME: Remove dummy argument.
+  Args.insert(Args.end(), ArgList.begin(), ArgList.end());
+
+  // FIXME: Find a cleaner way to force the driver into restricted modes. We
+  // also want to force it to use clang.
+  Args.push_back("-fsyntax-only");
+
+  // FIXME: We shouldn't have to pass in the path info.
+  driver::Driver TheDriver("clang", llvm::sys::getHostTriple(),
+                           "a.out", false, false, *Diags);
+
+  // Don't check that inputs exist, they may have been remapped.
+  TheDriver.setCheckInputsExist(false);
+
+  llvm::OwningPtr<driver::Compilation> C(TheDriver.BuildCompilation(Args));
+
+  // Just print the cc1 options if -### was present.
+  if (C->getArgs().hasArg(driver::options::OPT__HASH_HASH_HASH)) {
+    C->PrintJob(llvm::errs(), C->getJobs(), "\n", true);
+    return 0;
+  }
+
+  // We expect to get back exactly one command job, if we didn't something
+  // failed.
+  const driver::JobList &Jobs = C->getJobs();
+  if (Jobs.size() != 1 || !isa<driver::Command>(Jobs.begin())) {
+    llvm::SmallString<256> Msg;
+    llvm::raw_svector_ostream OS(Msg);
+    C->PrintJob(OS, C->getJobs(), "; ", true);
+    Diags->Report(diag::err_fe_expected_compiler_job) << OS.str();
+    return 0;
+  }
+
+  const driver::Command *Cmd = cast<driver::Command>(*Jobs.begin());
+  if (llvm::StringRef(Cmd->getCreator().getName()) != "clang") {
+    Diags->Report(diag::err_fe_expected_clang_command);
+    return 0;
+  }
+
+  const driver::ArgStringList &CCArgs = Cmd->getArguments();
+  CompilerInvocation *CI = new CompilerInvocation();
+  CompilerInvocation::CreateFromArgs(*CI,
+                                     const_cast<const char **>(CCArgs.data()),
+                                     const_cast<const char **>(CCArgs.data()) +
+                                     CCArgs.size(),
+                                     *Diags);
+  return CI;
+}