FC: A new LLVM based Fortran Frontend

A new front end for Fortran ( https://github.com/compiler-tree-technologies/fc ) has been written in the design spirit of LLVM/Clang. This is a prototype version with approximately 20K+ lines of code. The compiler is close to Fortran 95 standard. The Front end is a complete end to end solution without semantic analysis. It compiles and runs 400+ unit test cases and 2 (503.bwaves_r and 548.exchange2_r) SPEC CPU 2017 Fortran benchmarks.

Major supported features inlcudes:

  1. Nested do, do-while, where, select-case, forall, implied-do constructs,
  2. Handling/Expanding Array Section expressions, Array constructors,
  3. IO Handling: File read/write with basic Formatting support.
  4. Support for around 40 Fortran Intrinsics like transpose, reshape, min, max, sum, etc
  5. Nested Functions/ Module/ Subroutines.
  6. Derived types are partially supported(WIP)
  7. Dynamic memory handling (allocate statement) using malloc/free.
  8. Very basic Debugging / TBAA support.

LLVM code generated is fairly optimized. The performance in SPEC becnhmarks are comparable(better in few cases) to flang and gfortran compilers in both speed and rate runs.

Feedback/ comments are welcome.

Prashantha N.R.
Compiler Tree Technologies