Bug 57098 - Use the LLVM optimizing compiler is disabled in Xamarin 4.5
Summary: Use the LLVM optimizing compiler is disabled in Xamarin 4.5
Alias: None
Product: iOS
Classification: Xamarin
Component: Xamarin.iOS.dll ()
Version: XI 10.10 (d15-2)
Hardware: PC Windows
: --- normal
Target Milestone: Untriaged
Assignee: Rolf Bjarne Kvinge [MSFT]
Depends on:
Reported: 2017-06-02 11:13 UTC by Saravanan
Modified: 2017-08-01 10:05 UTC (History)
4 users (show)

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

Disabled option marked in screenshot (117.21 KB, image/jpeg)
2017-06-02 11:13 UTC, Saravanan

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Description Saravanan 2017-06-02 11:13:02 UTC
Created attachment 22643 [details]
Disabled option marked in screenshot

Could not enable the options "Use the LLVM optimizing compiler" and "Use Thumb-2 instruction set for ARMv7 and ARMv7s" from Visual Studio/Xamarin studio after migrating Xamarin 4.5, this options are disabled in IDE. If i add properties <MtouchUseLlvm> and <MtouchUseThumb> as true manually in .csproj file, the option is checked in IDE but still not enabled.

Please provide your input on how to use these properties correctly? why these are not enabled in Xamarin 4.5?.

Similarly when i "enable concurrent garbage collector" on IDE, added "<MtouchEnableSGenConc>" instead "<MtouchUseSGen>" in .csproj file. Which is correct property?.

System Info:
Xamarin (c871575)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.
Xamarin.Android (448f54f)
Visual Studio extension to enable development for Xamarin.Android.
Xamarin.iOS (30b6e87)
Visual Studio extension to enable development for Xamarin.iOS.

Please update me resolution.
Comment 1 Manuel de la Peña [MSFT] 2017-06-05 09:30:20 UTC
Adding @rolf in cc since he has more information about this feature.
Comment 2 Rolf Bjarne Kvinge [MSFT] 2017-06-13 13:08:52 UTC
LLVM is not available for debug builds (because debugging doesn't work with LLVM).

If you select a release build, you can enable LLVM.

To use the concurrent garbage collector, just check the checkbox in the IDE.
Comment 3 Yue 2017-07-21 12:34:37 UTC
But appstore and ad-hoc build can't enable llvm too
Comment 4 Rolf Bjarne Kvinge [MSFT] 2017-08-01 10:05:51 UTC
@Yue, make sure "Enable debugging" is not selected in the "iOS Debug" project options.