| commit | 21029eaa94dfba218ca10611e3755898f1f02ca1 | [log] [tgz] |
|---|---|---|
| author | Tom Eccles <tom.eccles@arm.com> | Tue Apr 16 10:25:26 2024 +0100 |
| committer | Copybara-Service <copybara-worker@google.com> | Tue Apr 16 02:28:13 2024 -0700 |
| tree | 7534401cf5b7b1ae3711756bfccee2d48351197e | |
| parent | a86b1e05011eb5c8a30fea44eebca59ec57337e3 [diff] |
[flang][runtime] Add ACCESS library procedure (#88517) Re-land https://github.com/llvm/llvm-project/pull/88395 Two build-bots were broken by the old version: - https://lab.llvm.org/buildbot/#/builders/285/builds/245 - https://lab.llvm.org/buildbot/#/builders/21/builds/96988 The problem in both cases was that the compiler did not support `std::filesystem` (which I use in the unit test). I have removed the dependency upon std::filesystem because there isn't an easy way to add the right linker options so that this is supported correctly in all build environments [1] [1] https://gitlab.kitware.com/cmake/cmake/-/issues/17834 --- This is a GNU extension: https://gcc.gnu.org/onlinedocs/gfortran/ACCESS.html Used in SALMON: https://salmon-tddft.jp/download.html Unfortunately the intrinsic takes a file path to operate on so there isn't an easy way to make the test robust. The unit test expects to be able to create, set read write and execute permissions, and delete files called std::filesystem::temp_directory_path() / <test_name>.<pid> The test will fail if a file already exists with that name. I have not implemented the intrinsic on Windows because this is wrapping a POSIX system call and Windows doesn't support all of the permission bits tested by the intrinsic. I don't have a Windows machine easily available to check if Gfortran implements this intrinsic on Windows. GitOrigin-RevId: 668a58b8926473d731c41c55007f1fe4571ada86
Flang is a ground-up implementation of a Fortran front end written in modern C++. It started off as the f18 project (https://github.com/flang-compiler/f18) with an aim to replace the previous flang project (https://github.com/flang-compiler/flang) and address its various deficiencies. F18 was subsequently accepted into the LLVM project and rechristened as Flang.
Please note that flang is not ready yet for production usage.
Read more about flang in the docs directory. Start with the compiler overview.
To better understand Fortran as a language and the specific grammar accepted by flang, read Fortran For C Programmers and flang's specifications of the Fortran grammar and the OpenMP grammar.
Treatment of language extensions is covered in this document.
To understand the compilers handling of intrinsics, see the discussion of intrinsics.
To understand how a flang program communicates with libraries at runtime, see the discussion of runtime descriptors.
If you're interested in contributing to the compiler, read the style guide and also review how flang uses modern C++ features.
If you are interested in writing new documentation, follow LLVM's Markdown style guide.
Consult the Getting Started with Flang for information on building and running flang.