clang++ Assertion failure "too many large addends"

[jonpryor]

Apple platform

iOS

Framework version

net10.0-*, net11.0-ios

Affected platform version

.NET 10, .NET 10 11 Preview 6

Description

When trying to build a certain app for Native AOT, the build fails in a clang++ call from the <LinkNativeCode/> task.

Steps to Reproduce

Apologies, as the repro is not small…

git clone https://github.com/unoplatform/uno
cd uno
# error is not limited to this commit; commit used for consistency/future reproducibility
git checkout 83effab5c73cddf21ef3ee7598edd9f6e45771fb
dotnet publish -f net10.0-ios -p:UnoTargetFrameworkOverride=net10.0-ios -p:SkiaPublishAot=true -p:DebugType=none -p:UNO_DISABLE_ANALYZERS_IN_SAMPLES=true -bl src/SamplesApp/SamplesApp.Skia.netcoremobile/SamplesApp.Skia.netcoremobile.csproj

Note: -p:DebugType=none is present in order to work around dotnet/runtime#132164

Note: -p:SkiaPublishAot=true sets $(PublishAot)=true within SamplesApp.Skia.netcoremobile.csproj.

Eventually, the above dotnet publish command will fail (it takes awhile; after 302.4s in my case):

    /usr/local/share/dotnet/packs/Microsoft.iOS.Sdk.net10.0_26.1/26.1.10502/targets/Xamarin.Shared.Sdk.targets(1862,3): error 
      clang++ exited with code 1:
      0  0x10250552c  __assert_rtn + 252
      1  0x1023eb65c  ld::Fixup::setAddend(long long, std::__1::function<unsigned int (long long)>) + 352
      2  0x102450f9c  ld::DynamicAtom::addFixup(ld::file_format::FixupKind, unsigned int, ld::Atom const*, ld::Atom const*, long long) + 368
      3  0x1023f9190  ld::FixupFromRelocs::diff(relocation_info const&, relocation_info const&, long long) const + 252
      4  0x102411f98  ld::InputFiles::SliceParser::parseObjectFile(mach_o::Header const*) const + 5960
      5  0x10241d940  ld::InputFiles::SliceParser::parse() const + 696
      6  0x102420c48  ld::InputFiles::parseAllFiles(void (ld::AtomFile const*) block_pointer)::$_0::operator()(unsigned long, ld::FileInfo const&) const + 516
      7  0x18c7dd4c8  _dispatch_client_callout2 + 16
      8  0x18c7d81a4  _dispatch_apply_invoke3 + 336
      9  0x18c7dd4b0  _dispatch_client_callout + 16
      10  0x18c7c6630  _dispatch_once_callout + 32
      11  0x18c7d72f4  _dispatch_apply_invoke + 248
      12  0x18c7dd4b0  _dispatch_client_callout + 16
      13  0x18c7fad6c  _dispatch_channel_invoke.cold.9 + 28
      14  0x18c7d5adc  _dispatch_root_queue_drain + 708
      15  0x18c7d6120  _dispatch_worker_thread2 + 184
      16  0x18c97be84  _pthread_wqthread + 232
      ld snapshot written at /tmp/SamplesApp-2026-08-10-144756.ld-snapshot
      ld: Assertion failed: (_addend == uniqueIndex && "too many large addends"), function setAddend, file Fixup.cpp, line 1445.
      clang++: error: linker command failed with exit code 1 (use -v to see invocation)

The 3rd line from the end mentions /tmp/SamplesApp-2026-08-10-144756.ld-snapshot, which in turn contains an assert_info file:

Assertion failed: (_addend == uniqueIndex && "too many large addends"), function setAddend, file Fixup.cpp, line 1445.
0  0x10250552c  __assert_rtn + 252
1  0x1023eb65c  ld::Fixup::setAddend(long long, std::__1::function<unsigned int (long long)>) + 352
2  0x102450f9c  ld::DynamicAtom::addFixup(ld::file_format::FixupKind, unsigned int, ld::Atom const*, ld::Atom const*, long long) + 368
3  0x1023f9190  ld::FixupFromRelocs::diff(relocation_info const&, relocation_info const&, long long) const + 252
4  0x102411f98  ld::InputFiles::SliceParser::parseObjectFile(mach_o::Header const*) const + 5960
5  0x10241d940  ld::InputFiles::SliceParser::parse() const + 696
6  0x102420c48  ld::InputFiles::parseAllFiles(void (ld::AtomFile const*) block_pointer)::$_0::operator()(unsigned long, ld::FileInfo const&) const + 516
7  0x18c7dd4c8  _dispatch_client_callout2 + 16
8  0x18c7d81a4  _dispatch_apply_invoke3 + 336
9  0x18c7dd4b0  _dispatch_client_callout + 16
10  0x18c7c6630  _dispatch_once_callout + 32
11  0x18c7d72f4  _dispatch_apply_invoke + 248
12  0x18c7dd4b0  _dispatch_client_callout + 16
13  0x18c7fad6c  _dispatch_channel_invoke.cold.9 + 28
14  0x18c7d5adc  _dispatch_root_queue_drain + 708
15  0x18c7d6120  _dispatch_worker_thread2 + 184
16  0x18c97be84  _pthread_wqthread + 232

A similar assert happens when using .NET 11 Preview 6 with Xcode 26.6.

Did you find any workaround?

No response

Build logs

No response

[jonpryor]

@akoeplinger believes that this may be fixed with dotnet/runtime#124721.