[flang-commits] [flang] [flang] [mlir] Avoid clobbering mlir-tblgen target by defining dummy imported targets (PR #150987)

[via flang-commits]

Acture wrote:



> > I set `LLVM_TOOLS_BINARY_DIR` to the `bin` directory produced by the tblgen-only build (`${buildLlvmTools.tblgen}/bin`). I also tried pointing it to the `bin` directories from the libllvm package (`${libllvm.out}/bin`) and the full llvm build (`${llvm.out}/bin`), but none of them worked.
> 
> mlir-tblgen is in the install of MLIR. Did you make sure you have this binary in one of the path you tried to use?

I’ve just double-checked. In the Nix build setup the situation is a bit different: the tblgen tools are split into a dedicated output, so mlir-tblgen does not appear in the MLIR “install” tree. Concretely:

`
# From the tblgen build (${buildLlvmTools.tblgen}/bin):
$ ls /nix/store/5hynj7y0y5pjdfyfg6hhxi9f5mpxgl6p-mlir-20.1.6/bin/
mlir-linalg-ods-yaml-gen*        mlir-pdll-lsp-server*            mlir-rewrite*                    tblgen-lsp-server*
mlir-lsp-server*                 mlir-query*                      mlir-runner*                     update_core_linalg_named_ops.sh*
mlir-opt*                        mlir-reduce*                     mlir-translate*

# From the MLIR install output (${mlir.out}/bin)
$ ls  /nix/store/pfcxcpmhxc4944dd5pw9kx3fnla9vbzm-llvm-tblgen-20.1.6/bin/
clang-tblgen*                    llvm-lit*                        llvm-tblgen*                     update_core_linalg_named_ops.sh*
clang-tidy-confusable-chars-gen* llvm-min-tblgen*                 mlir-tblgen*
`

Are there any other expectations that I should satisfy for Flang’s configure step?

https://github.com/llvm/llvm-project/pull/150987