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What is AOT compilation?
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Answer from AI
AOT (Ahead-of-Time) compilation is the process of converting the program's source code or bytecode into machine code before runtime.
Key differences from JIT (Just-In-Time) compilation:
- Compilation time: Happens in advance, often during the application's build stage.
- Performance: Machine code is ready for execution immediately, which can improve startup time and peak performance, as there are no overheads for compilation during runtime.
- Executable size: Can be larger, as it includes all the compiled machine code.
- Platform dependence: The resulting machine code is specific to the target processor architecture and operating system.
Examples of usage:
- C/C++, Rust, Go (by default).
- .NET (Native AOT, ReadyToRun).
- Java (GraalVM Native Image).
- Angular (for the client-side of web applications).
Advantages:
- Fast startup
- Potentially higher peak performance
- Reduced resource consumption during execution (no JIT compiler)
- Improved security (no dynamic compilation)
Disadvantages:
- Increased build time
- Larger executable size
- Difficulties with reflection and dynamic code in some cases
- Platform dependence
Example of usage in .NET:
dotnet publish -c Release -r win-x64 /p:PublishAot=true
# Publishes a standalone application with AOT compilation for Windows x64
Example of GraalVM usage:
native-image -jar myapp.jar
# Creates a native executable from a JAR archive