Bug 47048 - RegisterTypeUnsafe reflects on immutable metadata during app startup
Summary: RegisterTypeUnsafe reflects on immutable metadata during app startup
Alias: None
Product: iOS
Classification: Xamarin
Component: General ()
Version: XI 10.2 (iOS 10.1)
Hardware: PC Windows
: --- enhancement
Target Milestone: 15.3
Assignee: Rolf Bjarne Kvinge [MSFT]
Depends on:
Reported: 2016-11-15 20:32 UTC by Jerome Laban
Modified: 2017-05-05 08:08 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Jerome Laban 2016-11-15 20:32:55 UTC
The dynamic registrar inspects (via RegisterTypeUnsafe) the whole app domain's types, interfaces and methods to find register-able NSObject inheriting types.

In a complex app, this processing can roughly 10% of the startup time.

Given that the package's content never changes, the build process should be able to provide a pre-computed table to the dynamic registrar, for types known at compile time.
Comment 1 Rolf Bjarne Kvinge [MSFT] 2016-11-16 06:06:06 UTC
This is already on the map.
Comment 2 Rolf Bjarne Kvinge [MSFT] 2017-05-05 07:52:49 UTC
There's a static registrar that does exactly what you're requesting.

You can select the static registrar by adding "--registrar:static" to the additional mtouch arguments in the project's iOS Build options.

The static registrar is the default for device builds, but not for simulator builds (using the static registrar makes the build longer; for the simulator the added build time is usually longer than the gained startup time, while for the device it's the opposite).

Some time ago we added an intermediate mode: we pre-compute (run the static registrar) for only Xamarin.iOS.dll, then we ship this information, and use this pre-computed information for simulator builds when we can. This speeds up the launch time in the simulator significantly, since we only need to process any user assemblies at runtime (in any case you can always manually select the static registrar anyway).