JuliaLang / julia / #37918

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Build Type

push

local

Committed by web-flow

Commit Message

add --trim option for generating smaller binaries (#55047)

This adds a command line option `--trim` that builds images where code
is only included if it is statically reachable from methods marked using
the new function `entrypoint`. Compile-time errors are given for call
sites that are too dynamic to allow trimming the call graph (however
there is an `unsafe` option if you want to try building anyway to see
what happens).

The PR has two other components. One is changes to Base that generally
allow more code to be compiled in this mode. These changes will either
be merged in separate PRs or moved to a separate part of the workflow
(where we will build a custom system image for this purpose). The branch
is set up this way to make it easy to check out and try the
functionality.

The other component is everything in the `juliac/` directory, which
implements a compiler driver script based on this new option, along with
some examples and tests. This will eventually become a package "app"
that depends on PackageCompiler and provides a CLI for all of this
stuff, so it will not be merged here. To try an example:

```
julia contrib/juliac.jl --output-exe hello --trim test/trimming/hello.jl
```

When stripped the resulting executable is currently about 900kb on my
machine.

Also includes a lot of work by @topolarity

---------

Co-authored-by: Gabriel Baraldi <baraldigabriel@gmail.com>
Co-authored-by: Tim Holy <tim.holy@gmail.com>
Co-authored-by: Cody Tapscott <topolarity@tapscott.me>

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