30f7a6cc42
When lowering allocatables, the generated calls to runtime functions were not using the runtime::createArguments utility which handles the required conversions. createArguments is where I added the implicit volatile casts to handle converting volatile variables to the appropriate type based on their volatility in the callee. Because the calls to allocatable runtime functions were not using this function, their arguments were not casted to have the appropriate volatility. Add a test to demonstrate that volatile and allocatable class/box/reference types are appropriately casted before calling into the runtime library. Instead of using a recursive variadic template to perform the conversions in createArguments, map over the arguments directly so that createArguments can be called with an ArrayRef of arguments. Some cases in Allocatable.cpp already had a vector of values at the point where createArguments needed to be called - the new overload allows calling with a vector of args or the variadic version with each argument spelled out at the callsite. This change resulted in the allocatable runtime calls having their arguments converted left-to-right, which changed some of the test results. I used CHECK-DAG to ignore the order. Add some missing handling of volatile class entities, which I previously missed because I had not yet enabled volatile class entities in Lower.
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.