1264d7a53a
The PR is to generalize the re-use of the `compilerRT` code of adding the path of `libflang_rt.runtime.a (so)` from AIX and LoP only to all platforms via a new function `addFlangRTLibPath`. It also added `-static-libflangrt` and `-shared-libflangrt` compiler options to allow users choosing which `flang-rt` to link to. It defaults to shared `flang-rt`, which is consistent with the linker behavior, except on AIX, it defaults to static. Also, PR #134320 exposed an issue in PR #131041 that the the overriding `addFortranRuntimeLibs` is missing the link to `libquadmath`. This PR also fixed that and restored the test case that PR #131041 broke.
Flang
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.
Getting Started
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.