83 строки
3.6 KiB
Markdown
83 строки
3.6 KiB
Markdown
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# NativeAOT
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We've added *experimental* support for using [NativeAOT][1] when publishing iOS,
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tvOS, Mac Catalyst and macOS apps in .NET 8.
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NativeAOT may produce smaller and/or faster apps - or it may not. It's very
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important to test and profile to determine the results of enabling NativeAOT.
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Our initial testing shows significant improvements both in size (up
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to 50% smaller) and startup (up to 50% faster). For more information about
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performance see [.NET 8 Performance Improvements in .NET MAUI][3].
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However, it is important to point out that NativeAOT requires trimming whole
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applications (using `<MtouchLink>Full</MtouchLink>`, which is enabled by
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default) and is much more restrictive and aggressive in removing code which is
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not AOT compatible. As a result, if the applications is using some AOT
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incompatible constructs (e.g. dynamically referencing code for which a
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dependency cannot be statically determined), NativeAOT compiler might remove
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them during build time, which can result in crashes at runtime. To warn users
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about when this can happen, trimming and AOT warnings are produced and they
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should not be neglected. Instead, all such warnings should be addressed, code
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adapted accordingly, and the application must be tested and profiled in this
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configuration. Only then it is safe to assume that the application is
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compatible with NativeAOT and should not cause any unexpected behaviour.
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Finally, there could be cases when fixing mentioned trimming and AOT warnings
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is not possible, i.e. warnings coming from referenced frameworks or
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third-party libraries. In such cases, `<MtouchLink>SdkOnly</MtouchLink>` can
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be specified on the project level and could help as a workaround. This affects
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the application size, but even in this mode NativeAOT tends to produce up to
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28% smaller applications compared to Mono showing a great potential of this
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new experimental feature.
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## How to enable NativeAOT?
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NativeAOT is enabled by setting the `PublishAot` property to `true` in the project file:
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```xml
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<PropertyGroup>
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<PublishAot>true</PublishAot>
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</PropertyGroup>
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```
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## Notes
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NativeAOT is only used when publishing (`dotnet publish`). In particular
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`dotnet build -t:Publish` is _not_ equivalent to `dotnet publish`, only
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`dotnet publish` will enable NativeAOT.
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**Unsupported** workaround: set the `_IsPublishing` property to `true` to make
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`dotnet build` think it's `dotnet publish`:
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```xml
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<PropertyGroup>
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<PublishAot>true</PublishAot>
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<_IsPublishing>true</_IsPublishing>
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</PropertyGroup>
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```
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This can be useful to install and run apps with `NativeAOT` from the IDE,
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because it's not possible to use `dotnet publish` when running from the IDE.
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## Compatibility and limitations
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There are no known issues specific to our platforms with NativeAOT; but the
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[limitations][2] are exactly the same as for other supported platforms.
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Nevertheless, we would like to point out a few features that are not available
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with NativeAOT, that are with Mono, when targeting Apple platforms:
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- NativeAOT does not support managed debugging.
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- There's no interpreter when using NativeAOT, and as such the
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`UseInterpreter` and `MtouchInterpreter` properties have no effect.
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- NativeAOT requires trimming, and `MAUI` isn't trimmer-safe, and thus
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unfortunately `MAUI` projects don't typically work with NativeAOT (we hope
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to rectify this situation for .NET 9).
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[1]: https://learn.microsoft.com/en-us/dotnet/core/deploying/native-aot
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[2]: https://learn.microsoft.com/en-us/dotnet/core/deploying/native-aot/?tabs=net8plus%2Cwindows#limitations-of-native-aot-deployment
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[3]: https://devblogs.microsoft.com/dotnet/dotnet-8-performance-improvements-in-dotnet-maui/
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