AOT+LLVM crashes starting with iOS 18_8303 workloads / Xcode 16

[alexanderdibenedetto]

Apple platform

iOS

Framework version

net8.0-*

Affected platform version

8.0.401, iOS 18_8303 workloads

Description

When building then running a .NET MAUI 8 project after updating to Xcode 16 / iOS 18_8303 workloads (and confirming the latest workloads released today for iOS has the same issue), the app crashes on start with an "Address size fault". Many libraries seem to face issues using LLVM after updating to XCode 16 / compatible workloads; the previous version using Xcode 15.4 worked without issue using LLVM.

Steps to Reproduce

1. File > New Project
2. Add libraries like System.Web.HttpUtility, System.Text.Json, etc (it affects dozens of libraries that I tested)
3. Add to CSPROJ:

   <MtouchUseLlvm>true</MtouchUseLlvm>
   <MtouchLink>SdkOnly</MtouchLink>
   <Optimize>true</Optimize>
   <MtouchInterpreter>-all</MtouchInterpreter>
   

4. Observe a crash on app launch (see attached)
   crash-ios18-8303.log

Did you find any workaround?

You must downgrade to Xcode 15.4 / last supported workloads for 15.4 in order to use AOT, OR disable AOT (no LLVM, all instead of -all). I tried finding libraries one by one that cause the crash and stopped after finding over 30 that cause crashes on launch - I'm not excluding a massive list one by one.

For performance reasons, it is incredibly important to not be forced into not aoting any libraries.

Relevant logs

No response

[alexanderdibenedetto]

Here's a list of all the ones I found published by Microsoft alone that can have this issue:

System.Web.HttpUtility,System.Threading,System.Threading.Channels,System.Text.RegularExpressions,System.Text.Json,System.Text.Encodings.Web,System.Security.Cryptography,System.Security.Claims,System.Runtime.Serialization.Primitives,System.Runtime.Numerics,System.Private.Xml,System.Private.Uri,System.ObjectModel,System.Net.WebProxy,System.Net.WebHeaderCollection,System.Net.Sockets,System.Net.ServicePoint,System.Net.Security,System.Net.Requests,System.Net.NetworkInformation,System.Net.NameResolution,System.Net.Mail,System.Net.Http,System.Net.Http.Json,System.Memory,System.Linq,System.Linq.Expressions,System.IO.Compression,System.Drawing.Primitives,System.Diagnostics.TraceSource,System.Diagnostics.Process,System.Diagnostics.DiagnosticSource,System.Console,System.ComponentModel,System.ComponentModel.TypeConverter,System.ComponentModel.Primitives,System.Collections,System.Collections.Specialized,System.Collections.NonGeneric,System.Collections.Immutable,System.Collections.Concurrent,Microsoft.CSharp

[rolfbjarne]

I'm not able to reproduce this; could you attach a complete test project I can use?

[alexanderdibenedetto]

@rolfbjarne here you go! thank you for all your help btw - I've always appreciated your responsiveness on this repository. If you deploy Release to iOS you can reproduce the crash. I should have mentioned you need to actually make use of one of the affected libraries; I've chosen the Microsoft.Extensions.Resilience library as the example. I used your tip about stripping symbols on another question in order to see that it is the same issue.
llvmCrashDemo.zip

[rolfbjarne]

That project works for me when I run from the command line like this:

dotnet build -t:Run /p:Configuration=Release /p:RuntimeIdentifiers=ios-arm64 /p:_DeviceName="Rolf's iPhone 15"

Are you using VS or VS Code?

[alexanderdibenedetto]

Can you try again with this project? llvmCrashDemo.zip

I added another new line for creating an HttpClient that reproduces well with:

 dotnet publish -c Release -f net8.0-ios ./llvmCrashDemo/llvmCrashDemo.csproj

I then upload with apple configuration 2 to remove any reliance on .NET tools that may cause issues.

[rolfbjarne]

This is rather puzzling, I still can't reproduce, and I did it the exact same you do.

Have you seen this on more than one device (if you have more than one device available)?

Also could you attach (or host on a file-sharing service like Dropbox, since it might be too big) the .ipa you installed on your device using Apple Configurator?