a42bb8b57a
This patch moves the CommonArgs utilities into a location visible by the Frontend Drivers, so that the Frontend Drivers may share option parsing code with the Compiler Driver. This is useful when the Frontend Drivers would like to verify that their incoming options are well-formed and also not reinvent the option parsing wheel. We already see code in the Clang/Flang Drivers that is parsing and verifying its incoming options. E.g. OPT_ffp_contract. This option is parsed in the Compiler Driver, Clang Driver, and Flang Driver, all with slightly different parsing code. It would be nice if the Frontend Drivers were not required to duplicate this Compiler Driver code. That way there is no/low maintenance burden on keeping all these parsing functions in sync. Along those lines, the Frontend Drivers will now have a useful mechanism to verify their incoming options are well-formed. Currently, the Frontend Drivers trust that the Compiler Driver is not passing back junk in some cases. The Language Drivers may even accept junk with no error at all. E.g.: `clang -cc1 -mprefer-vector-width=junk test.c' With this patch, we'll now be able to tighten up incomming options to the Frontend drivers in a lightweight way. --------- Co-authored-by: Cameron McInally <cmcinally@nvidia.com> Co-authored-by: Shafik Yaghmour <shafik.yaghmour@intel.com>
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.