Compiler Explorer

Compiler Explorer is an interactive compiler. The left-hand pane shows editable C, C++, Rust, Go, D, Haskell, Swift, Pascal (and some more!) code. The right, the assembly output of having compiled the code with a given compiler and settings. Multiple compilers are supported, and the UI layout is configurable (thanks to GoldenLayout). There is also an ispc compiler ? for a C variant with extensions for SPMD.

Try out at godbolt.org

You can support this project on Patreon.

Compiler Explorer follows a Code of Conduct which aims to foster an open and welcoming environment.

Compiler Explorer was started in 2012 to serve my needs at my previous employer to show how C++ constructs translated to assembly code. It started out as a tmux session with vi running in one pane and watch gcc -S foo.cc -o - running in the other. Since then, it has become a public website serving around 140,000 compilations per day.

Contact us

For general discussion, please join the cpplang slack channel #compiler_explorer or the public mailing list

If you are interested in developing, or want to see the discussions between existing developers, feel free to join the cpplang slack channel #ce_implementation or the development mailing list

Feel free to raise an issue on github or email Matt directly for more help.

Developing

Compiler Explorer is written in Node.js.

Assuming you have a compatible version of node installed, simply running make ought to get you up and running with an Explorer running on port 10240 on your local machine: http://localhost:10240/. Currently Compiler Explorer requires the latest LTS node version (v8) installed, either on the path or at NODE_DIR (an environment variable or make parameter).

Running with make EXTRA_ARGS='--language LANG' will allow you to load LANG exclusively, where LANG is one for the language ids/aliases defined in lib/languages.js. The Makefile will automatically install all the third party libraries needed to run; using yarn to install server-side and client side components.

The config system leaves a lot to be desired. Work has been done on porting CCS to Javascript and then something more rational can be used.

A Road map is available which gives a little insight into the future plans for Compiler Explorer.

Running a local instance

If you want to point it at your own GCC or similar binaries, either edit the etc/config/LANG.defaults.properties or else make a new one with the name LANG.local.properties, substituting LANG as needed. *.local.properties files have the highest priority when loading properties.

When running in a corporate setting the URL shortening service can be replaced by an internal one to avoid leaking source code outside of the organization. This is done by adding a new module in static/urlshorten-myservice.js and setting the urlShortenService variable in configuration. This module should export a single function, see the google module for an example. urlShortenService can also be set to none to disable url shortening altogether.

RESTful API

There's a simple restful API that can be used to do compiles to asm and to list compilers.

You can find the API documentation here.

Credits

Compiler Explorer is maintained by the awesome people listed in the AUTHORS file.

We would like to thank the contributors listed in the CONTRIBUTORS file, who have helped shape Compiler Explorer.

We would also like to specially thank these people for their contributions to Compiler Explorer:

• Gabriel Devillers (while working for Kalray)
• Johan Engelen
• Joshua Sheard
• Marc Poulhiès
• Andrew Pardoe

We would like to thank JetBrains for their support and for donating licenses to their excellent products to develop Compiler Explorer.