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

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

BTW, if this is not too late, I feel this work might be worth to be in other clang module (maybe in supporting) than driver (and let driver to link it). The idea is, the tools needs to understand modules, but it is complex. You can find similar works in clangd's ModulesBuilder. It is too expensive for every tool (and clang-tidy or whatever else) to do the same thing. It will be good if clang can provide such ability for it. And I think your work is a good candidate.

In one word, I hope this to be ability of clang to allow clang based tools to understand modules (of course, including the clang driver itself).

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