a8db1fb9b5
This patch updates fir.coordinate_op to carry the field index as attributes instead of relying on getting it from the fir.field_index operations defining its operands. The rational is that FIR currently has a few operations that require DAGs to be preserved in order to be able to do code generation. This is the case of fir.coordinate_op, which requires its fir.field operand producer to be visible. This makes IR transformation harder/brittle, so I want to update FIR to get rid if this. Codegen/printer/parser of fir.coordinate_of and many tests need to be updated after this change.
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.