RyuJIT: Microsoft's new 64-bit .Net compiler

Microsoft made available this week for public testing a build of a new 64-bit .Net compiler built by the company's .Net runtime code-generation team.

The new just-in-time compiler is codenamed "RyuJIT."("Ryujin" is the deity of the sea in Japanese mythology.) 

In a September 30 blog post on the .Net Framework blog, Microsoft execs noted there's already a 64-bit .Net JIT compiler. But the new, next-generation X64 RyuJIT "compiles code twice as fast," they claim.

"The 64-bit JIT currently in .NET isn’t always fast to compile your code, meaning you have to rely on other technologies such as NGen or background JIT to achieve fast program startup," acknowledged the post author, Andrew Pardoe, PM Manager for the Common Language Runtime (CLR) Runtime PM team.

RyuJIT is based off of the same codebase as the x86 JIT, according to the blog post. While the Community Technology Preview of RyuJIT is only for x64 right now, it's a "modern" compiler that will "be the basis of all our JIT compilers in the future," including x86, ARM, MDIL (Machine Dependent Intermediate Language) and whatever else comes along." Pardoe said.

"Having a single codebase means that .NET programs are more consistent between architectures—put another way, you generally get bug-for-bug compatibility. But having a single codebase also means we can innovate faster and bring you more code generation features more quickly," Pardoe blogged.

There's no date available as to when Microsoft expects to declare RyuJIT "RTM." But once it is, it will replace the existing Microsoft X64 JIT compiler. It's also worth noting that RyuJIT is intended as a replacement for the .Net compiler only, so it seemingly isn't the coming Microsoft compiler that can compile both C# and C++.

RyuJIT currently only works on 64-bit editions of Windows 8.1 or Windows Server 2012 R2, though this won't always be the case. The RyuJIT installer can be downloaded directly here.