Bug 35834 - AOT + LLVM result in enormous APK
Summary: AOT + LLVM result in enormous APK
Alias: None
Product: Android
Classification: Xamarin
Component: MSBuild ()
Version: 6.0.99
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Jonathan Pryor
Depends on:
Reported: 2015-11-13 07:45 UTC by Przemysław Raciborski
Modified: 2015-11-23 17:28 UTC (History)
5 users (show)

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

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Description Przemysław Raciborski 2015-11-13 07:45:30 UTC
Is it normal that APK without AOT has ~30mb size and generated APK with AOT + LLVM size is ~80 mb?
I use multidex - my app uses a lot of external libraries google play, facebook sdk and so on..
Comment 1 Jonathan Pryor 2015-11-23 17:28:38 UTC
> Is it normal that APK without AOT has ~30mb size and generated APK with AOT +
> LLVM size is ~80 mb?


At present, we don't have any IL stripping support, for enabling AOT is purely *additive* to previous .apk sizes, meaning your existing 30MB app w/o AOT will continue to be *at least* 30MB with AOT enabled. That 30MB is your floor.

Next, for *each* ABI that your app supports -- armeabi-v7a, x86, etc. -- every assembly that your app contains is AOT'd, and AOT'ing an assembly frequently results in a *larger* file than the source assembly. So you're *at least doubling* the "instruction" size (IL + machine code), and that's if your .apk only supports a single ABI.

Additionally, when it comes to generics AOT will need to emit expansions for every known instantiation, which can *really* cause machine code size to bloat.

AOT is for performance (reduced JIT times), *not* for app sizes.