Graal-Erlang is a Graal-based implementation of the Erlang, which uses the Truffle and runs on Java 8.

It works from Erlang source code, and reconstruct the AST inside the Truffle. Truffle provides many optimization, thus the execution speed can highly improved.

The internal method is the following:

• Convert the source to Erlang AST using the erlang/parser.erl
  • For this, you have to compile the parser.erl first to parser.beam.
• The AST file is ready to load. This is achived by the ErlAstParser class.
• Ready!

$ mkdir work
$ cd work
$ hg clone https://bitbucket.org/allr/mx
$ export PATH=$PWD/mx:$PATH
$ mkdir graal-compiler-workspace
$ cd graal-compiler-workspace
$ mx sclone http://hg.openjdk.java.net/graal/graal-compiler graal
$ git clone https://github.com/baratharon/graal-erl
$ ls -1
graal
graal-erl
jvmci
truffle

Optionally, you can use Eclipse. To generate the Eclipse project files, use the following commands:

$ cd graal-erl
$ mx ideinit

Instead of using the "raw" Mercurial and git commands, use mx to update the working copy.

$ mx spull

Use the mx for build as well.

$ mx build

Basically, use mx to run it. However, this will run in interpreted mode, and no runtime optimizations will occur.

$ mx erl

To speed up things, add some extra arguments:

$ mx --jdk jvmci --dynamicimport graal erl

The Graal-Erlang can be used for two different purposes.

OTP ring0 startup. All arguments are passed to the otp_ring0:start/2 function. The startup sequence is performed by the OTP ring0. Any arguments can be used what the "erl" command takes.

$ mx erl -init_debug -pa ~/graal-erl/erlang/test -run erlparse03 main "lists:seq(1,100)." -run init stop -noshell

To try the benchmarks, use this example:

$ mx erl -p1 ~/graal-erl/erlang/bg -run pidigits main 1000 -run init stop -noshell

The "independent" refers to the independence from the OTP ring0 startup. This mode will not start any official processes. The result is an empty Erlang runtime system. Also, modules can be loaded into the runtime system with the -file FILE flag. To select the function to execute, use the -mf MODULE FUNCTION flag. All extra parameters will be passed to the selected function as a list of strings. That means, the selected function can be a function with 0 arguments, and with 1 arguments (the list of strings) as well. To force the usage of the list of strings, use the -- flag. After this flag, all remaining arguments are converted to one list of strings. Also, this can be empty.

$ mx erl -independent -file ~/graal-erl/erlang/list41.erl -mf list41 main

Without any -file FILE flag, the standard input will be used as source.

Important: the first line must contain the module attribute.

Note: the same thing will happen, when the OTP ring0 startup is used.

Example run:

$ mx erl -independent -mf tmp main
-module(tmp).

fact(0) ->
    1;   
fact(N) ->
    N * fact(N-1).


main() ->
    fact(5).

(here Ctrl+D was pressed)

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$

• GRAAL_ERL_PARSER_PATH sets the path to the parser.beam
• GRAAL_ERL_ROOT_DIR sets the the Erlang root directory (defaults to /usr/lib/erlang)