LLVM 13.0 released with Flang

The official release notes say: Flang is now included in the binary packages released by LLVM.


Does it mean LLVM Flang can now produce an executable without calling an external compiler?


Flang as the Fortran front-end is now included in the official LLVM binary packages.


LLVM 13.0 is available in Fedora 35. I have made some tests in a Fedora Rawhide virtual machine. There is flang-new, which can’t produce yet an executable:

$ flang-new --version
flang-new version 13.0.0 (Fedora 13.0.0~rc1-1.fc35)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ flang-new hello.f90
error: code-generation is not available yet

and the flang script:

$ flang --version
flang version 13.0.0
$ flang hello.f90
$ ./a.out
 Hello World!
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Trying to add a use iso_c_binding statement in an hello world example, I am quite confused:

$ flang hello.f90
./hello.f90:2:9: error: Cannot read module file for module 'iso_c_binding': Source file 'iso_c_binding.f18.mod' was not found
      use iso_c_binding
error: Semantic errors in hello.f90
flang: in /home/osboxes, flang-new failed with exit status 1: /usr/bin/flang-new -fc1 -module-suffix .f18.mod -fdebug-unparse -fno-analyzed-objects-for-unparse hello.f90

I used flang but the error message says flang-new failed. And why the iso_c_binding module is not available?

Classic Flang (GitHub - flang-compiler/flang: Flang is a Fortran language front-end designed for integration with LLVM.) is a separate compiler and not shipped along with llvm.

flang-new is the driver of the Fortran frontend shipped along with llvm. flang is a shell script that can parse, perform semantics, and unparse and call an external compiler to do the codegen. flang basically calls flang-new internally. When codegen becomes available then the flang script will be removed/renamed and flang-new will be renamed as flang.

I don’t know why the iso_c_binding usage is not working. I expected it to work. Maybe you can file a bug (Bug List).

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Thanks for clarifying things about flang / flang-new.
I will make more tests about iso_c_binding and see if everything is correctly installed in my Fedora Rawhide.