[llvm] [Mips][nanoMIPS] Add initial nanoMIPS target support (PR #223032)

[via llvm-commits]

nrakovic wrote:

> I'd expect to see some testing in tools/llvm-readobj, since you're adding llvm-readobj support in this PR (via the Object changes, if I'm not mistaken). There's already testing there for other MIPS relocation dumping, for example. There are probably other cases too.

Thanks for the feedback. The relocation dumping is tested in the "Add ELF and relocation support" commit (llvm/test/tools/llvm-readobj/ELF/reloc-types-nanomips.test), modelled on reloc-types-mips.test.

You do bring up an important point. We initially planned e_flags testing to be added in later stages along with the e_flags themselves, but we ended up including the e_flags in the initial batch without the tests.
We had another look and it seems we also omitted an EM_NANOMIPS case in file-header-machine-types.test.

Current plan is to add the following to the PR:
- e_flags decoding in ELFDumper plus llvm-readobj/ELF/nanomips-eflags.test
- obj2yaml/ELF/nanomips-eflags.yaml
- an EM_NANOMIPS case in file-header-machine-types.test

Do you think these changes along with the existing reloc-types-nanomips.test would provide adequate test coverage?


https://github.com/llvm/llvm-project/pull/223032