[clang] [clang][modules-driver] Add dependency scan and dependency graph (PR #152770)

[Naveen Seth Hanig via cfe-commits]

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@@ -0,0 +1,112 @@
+//===- ModulesDriver.h - Driver managed module builds --------*- 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file defines functionality to support driver managed builds for
+/// compilations which use Clang modules or standard C++20 named modules.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_DRIVER_MODULESDRIVER_H
+#define LLVM_CLANG_DRIVER_MODULESDRIVER_H
+
+#include "clang/Driver/Types.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+namespace vfs {
+class FileSystem;
+} // namespace vfs
+namespace opt {
+class Arg;
+} // namespace opt
+} // namespace llvm
+
+namespace clang {
+class DiagnosticsEngine;
+namespace driver {
+class Compilation;
+} // namespace driver
+} // namespace clang
+
+namespace clang::driver::modules {
+
+/// A list of inputs and their types for the given arguments.
+/// Identical to Driver::InputTy.
+using InputTy = std::pair<types::ID, const llvm::opt::Arg *>;
+
+/// A list of inputs and their types for the given arguments.
+/// Identical to Driver::InputList.
+using InputList = llvm::SmallVector<InputTy, 16>;
+
+/// Checks whether the -fmodules-driver feature should be implicitly enabled.
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naveen-seth wrote:

To confirm, you also want to revert #153497 for now?

https://github.com/llvm/llvm-project/pull/152770