[flang-commits] [flang] [llvm] [Flang] Add mock flang driver (PR #203481)

[Michael Kruse via flang-commits]

Meinersbur wrote:

The `flang` driver invokes itself with `-fc1` just like clang does (where does the idea of "separate executable" come from? Different process: yes[^1]; different executable: no). While I think it is possible to create a driver without the `-fc1` implementation, it would not help us: Compilation of CMake's `CMakeFortranCompilerId.F` requires `-fc1`, even if it is only the preprocessor.

[^1]: when there is just one `-cc1` invocation, clang (but currently not flang) calls cc1_main in-process, saving on fork overhead.

https://github.com/llvm/llvm-project/pull/203481