Fortran -> JS Docker image

This project provides a Docker image that contains a working FORTRAN -> Javascript compiler.

TODO

1. Actually deliver on claim #1 above

• make Docker image that can run emscripten
• add gcc + dragonegg to image
• produce C main + Fortran obj
• make F->js library files
• support Fortran standard library (small)
• support Fortran main

Work in Progress

There is a docker image that includes llvm, gfortran, dragonegg, and emscripten.

I am trying to figure out how to do automate testing and how to automate compilation of simple hello-world examples.

Using the current image

To start messing around, first checkout this repository

$ git checkout ssh:github.com:smikes/femscripten.git
$ cd femscripten

get the docker image --

$ docker run -t -i -v `pwd`:/mnt/test smikes/femscripten:devel /bin/bash
$ cd /mnt/test
$ . setup-env.sh

Now you are inside the docker container and should have access to the compiler commands.

Commands

emgf

This is the main useful program. It is a shell script which takes one argument, a fortran file, and generates an emscripten-compatible object file.

$ emgf foo.f   => produces foo.o

BUGS: This currently also produces foo.s, foo.ll ; and it uses an ugly workaround to get from the dragonegg default target (below):

target datalayout = "e-p:32:32:32-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f16:16:16-f32:32:32-f64:32:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
target triple = "i386--linux-gnu"

to the correct emscripten target.

However it works! Good enough for now.

Examples

Times

$ cd examples/times
$ make

There is one main function, in times-main.c. It expects an external function named times_ (note the C-to-FORTRAN naming convention) which takes two floats by reference, and returns their product.

There are two implementaions of times_ provided: one in C (times-c.c) and one in FORTRAN 77 (times-f.f).

The make should succeed and you should be able to run both quasi-executables through node:

$ node times-c.js
6.000000

$ node times-f.js
6.000000

Lapack

$ cd examples/lapack
$ make

This is an example that uses a very simple subroutine from LAPACK - IDAMAX, find the index of the maximum element in an array of doubles.

$ node lapack.js
let's ask BLAS/IDAMAX what's the index of the largest value
in the array: { 0.0, 300.0, 1.345e39, -452.0 }; 

It should be the third element; we got ==> 3

Note that FORTRAN has 1-based arrays by default

Hello

Not yet working -- some gfortran library functions need to be implemented.

$ emgf hello_world.f
$ emcc -o hello_world.js hello_world.o
warning: unresolved symbol: _gfortran_st_write_done
warning: unresolved symbol: _gfortran_transfer_character_write
warning: unresolved symbol: _gfortran_set_args
warning: unresolved symbol: _gfortran_set_options
warning: unresolved symbol: _gfortran_st_write