Exit with quick_exit when using debug UCRT

[MichalStrehovsky]

Resolves #108640.

Cc @dotnet/ilc-contrib @janvorli

[jkotas]

I expect that this will break tracing tests. Tracing depends on C runtime shutdown notification to close the session:

runtime/src/coreclr/nativeaot/Runtime/startup.cpp

Line 375 in be013ed

atexit(&OnProcessExit);

Also, the same fundamental problem exists in regular coreclr as well.

[janvorli]

It seems that the only way to fix the problem and keep the cleanup at exit untouched would be to link to ucrt dynamically. The cleanup then occurs in DllMain of the library on DLL_PROCESS_DETACH.

[janvorli]

I meant the low level CRT cleanup, not the atexit stuff.

[filipnavara]

Tracing depends on C runtime shutdown notification to close the session

Playing the devil's advocate, you can always make that a at_quick_exit.

Ah, damn, that's C++ and not in ucrt, so that would not help.

[jkotas]

Ah, damn, that's C++ and not in ucrt, so that would not help.

There is no C++ in the mix. Neither atexit or at_quick_exit are directly exposed by the ucrt.dll. They are statically linked stubs that use CRT global state for .exes and module-local state for .dlls. For example:

• Exiting via quick_exit from main still runs atexit handlers registered in other .dlls in the process, but it does not run at_quick_exit handlers registered in other .dlls in the process
• Exiting via quick_exit from .dll with statically linked CRT (the "global" state is module-local with static linking) runs at_quick_exit handlers registered in the given .dll, but it does not run atexit nor at_quick_exit handlers registered by the .exe

[jkotas]

/azp run runtime-nativeaot-outerloop

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