[llvm-branch-commits] [clang] [flang] [lld] [llvm] [Flang] LLVM_ENABLE_RUNTIMES=FortranRuntime (PR #110217)

[Michael Kruse via llvm-branch-commits]

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@@ -34,6 +34,8 @@ endfunction()
 
 
 # llvm_ExternalProject_Add(name source_dir ...
+#   ENABLE_FORTRAN
+#     External project requires the Flang compiler
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Meinersbur wrote:

Flang is required to build FlangRuntime. Currently, there is just one file `iso_fortran_env_impl.f90` it is needed for, but there should be no reason why not implement parts of the language's runtime in the language itself as all out C/C++ runtimes do. Additionally, in the future I hope that we can use it to compile the `.mod` files as well.

`ENABLE_FORTRAN` would build Flang before the runtimes and error-out Flang is not part of a bootstrap build. If there no runtime dependent on Fortran then we also don't need to depend on Flang. Adding `ENABLE_CPLUSPLUS` would be kind of pointless because even single runtime we have depends on Clang (unless I am mistaken?).

https://github.com/llvm/llvm-project/pull/110217