Platform build support reference

When you build your project, Burst compiles your code and creates a single dynamic library in the Plugins folder for the platform you’re targeting. For example, on Windows, the path is Data/Plugins/lib_burst_generated.dll.

Note: If your target platform is iOS, Unity instead generates a static library to meet Apple’s submission requirements for TestFlight.

The job system runtime loads the generated library the first time a Burst compiled method is invoked.

To control Burst’s AOT compilation, use the settings in the Burst AOT Settings section of the Project Settings window (Edit > Project Settings > Burst AOT Settings). For more information, refer to Burst AOT Settings reference.

Platforms without cross compilation

If you’re compiling for a non-desktop platform, Burst compilation requires specific platform compilation tools (similar to IL2CPPA Unity-developed scripting back-end which you can use as an alternative to Mono when building projects for some platforms. More info
See in Glossary). Desktop platforms (macOS, Linux, Windows) don’t need external toolchain support.

The table below lists the level of support for AOT compilationAhead of Time (AOT) compilation is an optimization method used by all platforms except iOS for optimizing the size of the built player. . More info
See in Glossary on each platform. If you select an invalid target (one with missing tools, or unsupported), Unity doesn’t use Burst compilation, but still builds the target without Burst optimizations.

Note: Burst supports cross-compilation between desktop platforms (macOS/Linux/Windows) by default.

Note: The maximum target CPU is hardcoded per platform. For standalone builds that target desktop platforms (Windows/Linux/macOS) you can choose the supported targets via the Burst AOT Settings.

Unsupported project types

Some projects can’t use Burst as the compiler:

• Android projects from the Linux Editor.
• Xcode projects generated from the Create Xcode Project option.

Multiple Burst targets

When Burst compiles multiple target platforms during a build, it has to perform separate compilations. For example, if you want to compile X64_SSE2 and X64_SSE4, Burst has to do two separate compilations to generate code for each of the targets you choose.

To keep the combinations of targets to a minimum, Burst target platforms require multiple processor instruction sets underneath:

• SSE4.2 is gated on having SSE4.2 and POPCNT instruction sets.
• AVX2 is gated on having AVX2, FMA, F16C, BMI1, and BMI2 instruction sets.
• ARMV8A is a basic Armv8-A CPU target
• ARMV8A_HALFFP is ARMV8A plus the following extensions: fullfp16, dotprod, crypto, crc, rdm, lse. In practice, this means Cortex A75/A55 and later cores.
• ARMV9A is ARMV8A_HALFFP plus SVE2 support. In practice, this means Cortex X2/A710/A510 and later cores. Important: this target is currently experimental.

Dynamic dispatch based on runtime CPU features

For all x86/x64 CPU desktop platforms, as well as for 64-bit Arm on Android, Burst takes into account the CPU features available at runtime to dispatch jobs to different versions it compiles.

For x86 and x64 CPUs, Burst supports SSE2 and SSE4 instruction sets at runtime only.

For example, with dynamic CPU dispatch, if your CPU supports SSE3 and below, Burst selects SSE2 automatically.

Additional resources

• Burst AOT Settings reference
• Editor reference