[clang] [lld] [llvm] Integrated Distributed ThinLTO (DTLTO): Initial support (PR #126654)

[Justin Cady via cfe-commits]

justincady wrote:

I just want to double check my understanding. :)

If I were to convert [this example](https://gist.github.com/MaskRay/24f4e2eed208b9d8b0a3752575a665d4#distributed-thinlto) to its functional equivalent in DTLTO, would it be:

```
clang -fuse-ld=lld -O2 -flto=thin -fthinlto-distributor=distributor_process a.c b.c c.c
```

Where:

- `distributor_process` receives a JSON file specifying all intermediate jobs
    - If necessary I can use `-Xthinlto-distributor=` to pass extra arguments to `distributor_process`
- Each job invokes `--thinlto-remote-opt-tool` (defaults to clang)
- LLD waits for the jobs to complete and performs the final link

Is that correct?

https://github.com/llvm/llvm-project/pull/126654