I've tried and given up on this a couple of times, so I'm describing my progress to date in case anyone has advice or wants to try it. It's easy to generate a large LLVM bitcode file containing the julia/base library. Run the following from within the julia/base directory:

../julia --build XX --dump-bitcode=yes --compile=all -J ../usr/lib/julia/sys0.ji -f sysimg.jl

Now, you should have an XX.bc file in the base directory. To identify functions in the bc file, use the following:

llvm-nm XX.bc | grep _abs_

That'll give something like:

T jlcall_abs_24823
T jlcall_abs_57792
T jlcall_abs_57794
T jlcall_abs_57795
T jlcall_abs_57796
T julia_abs_24823
T julia_abs_42171
T julia_abs_42172
T julia_abs_42173
T julia_abs_42174
T julia_abs_42175
T julia_abs_57792
T julia_abs_57793
T julia_abs_57794
T julia_abs_57795
T julia_abs_57796
T julia_abs_57797
T julia_abs_57798
T julia_abs_57799
T julia_abs_57800
T julia_abs_57801
T julia_abs_57802
T julia_abs_57803
T julia_abs_57804
T julia_abs_57805
T julia_abs_57806
T julia_abs_57807

To compile one of these functions to JavaScript, use emcc:

emcc -v XX.bc -o XX.js -s EXPORTED_FUNCTIONS="['_julia_abs_42171]"

A few of the simplest functions will compile to working JavaScript code. Several others will error as described below.

Here are current issues:

32-bit bitcode -- The most common error from the compilation step above is "i64 thing we can't legalize yet". Emscripten expects 32-bit bitcode. On a 64-bit platform, it can be difficult to generate 32-bit binaries. I tried modifying the contrib/build_sysimg.jl script to try to get 32-bit results by compiling with the i686 target. I wasn unsuccessful with that.
Struct issues -- Sometimes, we get the following error: Here's a bug report on this:

https://code.google.com/p/nativeclient/issues/detail?id=3932

Someone has compiled Rust with Emscripten and may have overcome similar issues:

https://www.reddit.com/r/rust_gamedev/comments/2n0x08/emscripten_experiments/cmcakwr

Also, here's a thread on using Emscripten with Rust that has interesting info:

Make Rust work with emscripten rust-lang/rust#2235
Symbol names -- Julia creates several symbol names with # in them. When converted to JavaScript, it causes errors. This one's probably not too bad to fix, either in Julia or in Emscripten.

Another issue is compiling libjulia to bitcode. I've gotten about 80% or more of it to compile with emcc. I had to strip out the libuv stuff. I haven't tried building any of the third-party libraries.

Uh oh!

Support compiling to JavaScript with Emscripten #9430

Description

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions