High number of external symbols in Windows 10 when creating sysimages with julia 1.10.0-beta1

[MariusDrulea]

The original issue is described in this comment: #50729 (comment). Sysimage creation failed because of large number of external symbols during linking. The fix/workaround for this is here: #50874. The chosen solution was to restrict the IMAGE_THREADS to 1 when the symbol count is higher than a threshold.

I opened a follow up discussion thread just for Windows10, as the original issue is now used to debate the Linux usecase (#50729)

Further to clarify:
(1) What is the source of this high number of external symbols in Windows 10? Can this be fixed instead such that we don't have to switch to a single thread and loose performance?
(2) I just tested the code on my Ubuntu laptop. Why the same source code works just fine in Ubuntu?

Maybe it's necessary to address issues in other tools (linker?, other?) instead of patching things on the julia side.

@pchintalapudi, @vtjnash, @gbaraldi, @vchuravy

[MariusDrulea]

I have found the same issue in golang 1.15: golang/go#43592
The solution was to remove the export-all-symbols flag given to the linker: golang/go@82f9c6c#diff-12cc6da4d4e7e3c99b7cd3fc668861b7448180c2b96523e80058db138cfd13f2L1428

I suspect something similar is happening in our issue.

[MariusDrulea]

This line maybe? https://github.com/JuliaLang/PackageCompiler.jl/blob/7f0607c990003099969f449c28ad2aeffd0671f4/src/PackageCompiler.jl#L655C28-L655C28

Does the package compiler really need to export all symbols?