Extended Description

This came up during a discussion on https://reviews.llvm.org/D112961.

As per the comment at the top of "flang/lib/Optimizer/CodeGen/DescriptorModel.h", various assumptions about the target machine are made in the code-gen layer. This is likely to cause --target (or e.g. -m64 and -m32) to malfunction when using Flang's interoperability with C (see how various CFI structures are lowered).

Note that --target is not available in the driver yet. Also, it is possible that the assumptions made when lowering the CFI structures will affect other parts of the code-gen too. However, I suspect that most things will work correctly when generating code for the host/native target.

I'm creating this issue as a placeholder and as a note for our future selves. This is currently not being investigated or worked on.

-Andrzej

[1] https://github.com/flang-compiler/f18-llvm-project
[2] https://github.com/llvm/llvm-project