Reko (Swedish: "decent, obliging") is a decompiler for machine code binaries. This project is freely available under the GNU General Public License.
The project consists of front ends, core decompiler engine, and back ends to help it achieve its goals. A command-line, a Windows GUI, and a ASP.NET front end exist at the time of writing. The decompiler engine receives inputs from the front ends in the form of either individual executable files or decompiler project files. Reko project files contain additional information about a binary file, helpful to the decompilation process or for formatting the output. The decompiler engine then proceeds to analyze the input binary.
Byte map view of a loaded ARM binary executable
Decompiled view of a loaded ARM binary executable
Reko has the ambition of supporting decompilation of various processor architectures and executable file formats with minimal user intervention. For a complete list, see the supported binaries page.
Please note that many software licenses prohibit decompilation or other reverse engineering of their machine code binaries. Use this decompiler only if you have legal rights to decompile the binary (for instance if the binary is your own.)
Documentation
To get acquainted with Reko's various features, you can read the user's guide. If you're interested in the internal workings of the project, see the wiki.
Getting support
You can report any issues you encounter or ask any Reko-related question on the issue tracker. You can also try the Reko Gitter.im chatroom. Reko is built by volunteers' efforts on their spare time, so adjust your response-time expectations accordingly.
Hacking
To build reko, start by cloning https://github.com/uxmal/reko. You can use an IDE or the command line to build the solution file src/Reko-decompiler.sln. Reko requires .NET Core 3.1 and C# 8 to compile. If you are an Windows IDE user, use Visual Studio 2019 or VS Code. If you wish to build using the command line, use the command
msbuild /p:Configuration={config} /p:Platform={platform} Reko-decompiler.sln
(provided you have msbuild installed). Replace {config} with either Debug or Release, and {platform} with x64 or x86. All external dependencies needed to build Reko are included in the external directory.
Note: please let us know if you still are not able to compile, so we can help you fix the issue.
If you're interested in contributing code, see the road map for areas to explore. The Wikihas more information about the Reko project's internal workings. Please consult the style guide.
Warnings and errors related to WiX
You will receive warnings or errors when loading the solution in Visual Studio or MonoDevelop if you haven't installed the WiX toolset on your development machine. You can safely ignore the warnings; the WiX toolset is only used when making MSI installer packages, and isn't even supported in MonoDevelop. You will not need to build an installer if you're already able to compile the project: the build process copies all the necessary files into If you do want to build an MSI installer with the WiX toolchain, you can download it here: http://wixtoolset.org/releases/
Errors related to CMake in Visual Studio
Depending on what you do Visual Studio might try to rebuild NativeProxy which depends on CMake. You can either install CMake and make sure it's added to your PATH or disable the project in Visual Studio.
Having CMake installed as part of Visual Studio is sufficient to run msbuild from the Developer Command Prompt but not when building from inside VS, unless you've added that to your global PATH. Installing CMake externally allows you to add it to PATH during the installation.
How do I start Reko?
The solution folder Drivers contains the executables that act as user interfaces: the directory WindowsDecompiler contains the GUI client for Windows users; MonoDecompiler contains the GUI client for Mono users; CmdLine is a command line driver.
Version 0.10.1
This maintenance release moves Reko from .NET Core 3.1 to .NET 5.0, resulting in some performance gains.
It also fixes the MSI installers for Windows, which had several issues (including #1066 and #1067). Special thanks to @smx-smx for his work on his CI integration work.
The Reko build system now assumes C# 9.0
Crude support for #define directives in the Reko C parser
Overhaul of PA-RISC and HP SOM loader
The command line driver --version switch displays the git hash used to build the binary.
Improvements in AArch64 disassembler and rewriter (with @rfalke as a driving force)