Only add symbols that are explicit entrypoints when building juliac image

[gbaraldi]

This currently just does a linear search over the items. We might want to change this datastructure to a hash table at some point, but given that I don't think libraries have too too many entrypoints this linear search should be fast enough.

[topolarity]

Looking good! I like this version much better

Thanks @gbaraldi 👍

[topolarity]

Is it possible to add #56603 as a test?

[inkydragon]

Test failed seems related.

gcc -march=native -mtune=native -m64 -c -o init.o /cache/build/tester-amdci4-8/julialang/julia-master/test/trimming/init.c   -std=gnu11 -I'/cache/build/tester-amdci4-8/julialang/julia-master/usr/include/julia' -fPIC
make: Leaving directory '/cache/build/tester-amdci4-8/julialang/julia-master/test/trimming'
make: Entering directory '/cache/build/tester-amdci4-8/julialang/julia-master/test/trimming'
/cache/build/tester-amdci4-8/julialang/julia-master/usr/bin/julia -t 1 -J /cache/build/tester-amdci4-8/julialang/julia-master/usr/bin/../lib/julia/sys.so --startup-file=no --history-file=no --output-o hello.o --output-incremental=no --strip-ir --strip-metadata --experimental --trim /cache/build/tester-amdci4-8/julialang/julia-master/usr/bin/../share/julia/juliac-buildscript.jl /cache/build/tester-amdci4-8/julialang/julia-master/test/trimming/hello.jl --output-exe true
warning: no code provided for function main() from main()
[171] signal 6 (-6): Aborted
in expression starting at none:0
gsignal at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)

https://buildkite.com/julialang/julia-master/builds/43995#0194929f-3352-4899-a516-022a0ca44b27/790-809

[JeffBezanson]

I pushed a version that should work. However there still seems to be a bug with const_return ccallables; including foo as an entrypoint in this test crashes.

[JeffBezanson]

OK I fixed that and added a test. But, we could ignore this whole situation entirely by skipping jl_reinit_ccallable for trimmed binaries. If you deploy without libjulia-codegen, it won't do anything anyway!