9f8ff4b77d
Bring the typed expression representation of a coindexed reference up to F'2023, which removed some restrictions that had allowed the current representation to suffice for older revisions of the language. This new representation is somewhat more simple -- it uses a DataRef as its base, so any subscripts in a part-ref can be represented as an ArrayRef there. Update the code that creates the CoarrayRef, and add more checking to it, as well as actually capturing any STAT=, TEAM=, & TEAM_NUMBER= specifiers that might appear. Enforce the constraint that the part-ref must have subscripts if it is an array. (And update a pile of copied-and-pasted test code that lacked such subscripts.)
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.