Stdlib pkgimages seems to be compiled with generic target

[KristofferC]

Making this an issue so I can add it to the milestone:

julia> cd(joinpath(Sys.BINDIR, "../share/julia/compiled/v1.11/Test"))

julia> Base.parse_image_targets(Base.parse_cache_header("JfdTE_4EB71.ji")[7])
1-element Vector{Base.ImageTarget}:
 generic; flags=0; features_en=(cx16)

julia> VERSION
v"1.11.0-beta1"

Ref #54093

[giordano]

I believe the problem is more general than stdlibs, it looks like setting JULIA_CPU_TARGET always results in compiling code only for the generic target, if we can trust the parsing done by Base.parse_image_targets and Base.parse_cache_header. Consider this script

# Cleanup Example precompile dir
example_dir = joinpath(first(Base.DEPOT_PATH), "compiled", "v$(Base.thisminor(Base.VERSION))"[begin:end-2], "Example")
rm(example_dir; force=true, recursive=true)

# Install Example
using Pkg
Pkg.activate(; temp=true, io=devnull)
Pkg.add("Example"; io=stdout)

# Find compile cache
pkg = Base.identify_package("Example")
cachefiles = Base.find_all_in_cache_path(pkg)
isempty(cachefiles) && error(pkg, " has not yet been precompiled for julia ", Base.VERSION, ". Reinstall the package with `Pkg.add(\"Example\"; io=stdout)` to see why")
pkgpath = Base.locate_package(pkg)
idx = findfirst(cachefiles) do cf
    Base.stale_cachefile(pkgpath, cf) !== true
end
targets = Base.parse_image_targets(Base.parse_cache_header(cachefiles[idx])[7])
# Show target
@show targets

With Julia v1.10.3 I get

% julia example_targets.jl 
targets = Base.ImageTarget[haswell; flags=0; features_en=(sse3, pclmul, ssse3, fma, cx16, sse4.1, sse4.2, movbe, popcnt, aes, xsave, avx, f16c, fsgsbase, bmi, avx2, bmi2, sahf, lzcnt)]
% JULIA_CPU_TARGET='generic;sandybridge,-xsaveopt,clone_all;haswell,-rdrnd,base(1);x86-64-v4,-rdrnd,base(1)' julia example_targets.jl 
targets = Base.ImageTarget[generic; flags=0; features_en=(cx16)]

Moreover, shuffling the targets:

% JULIA_CPU_TARGET='sandybridge,-xsaveopt,clone_all;generic;haswell,-rdrnd,base(0);x86-64-v4,-rdrnd,base(0)' julia example_targets.jl 
targets = Base.ImageTarget[sandybridge; flags=0; features_en=(sse3, pclmul, ssse3, cx16, sse4.1, sse4.2, popcnt, xsave, avx, sahf)]

So we always compile only for the first target of the list, whatever that is.

CC: @gbaraldi @vchuravy @timholy.

[KristofferC]

That's not too surprising since stdlibs are compiled identically to normal packages.