0c7e895de3
FrontendActions.cpp is currently one of the biggest compilation units in all of flang. Measuring its compilation gives the following metrics: User time (seconds): 139.21 System time (seconds): 4.65 Maximum resident set size (kbytes): 5891440 (5.61 GB) This commit separates out explicit invocations of the parser into a separate compilation unit - ParserActions.cpp - through helper functions in order to decrease the maximum compilation time and memory usage of a single unit. After the split, the measurements of FrontendActions.cpp are as follows: User time (seconds): 70.08 System time (seconds): 3.16 Maximum resident set size (kbytes): 3961492 (3.7 GB) While the ones for the newly created ParserActions.cpp as follows: User time (seconds): 104.33 System time (seconds): 3.37 Maximum resident set size (kbytes): 4185600 (3.99 GB) --------- Signed-off-by: Kajetan Puchalski <kajetan.puchalski@arm.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.