This particular one doesn’t have a huge impact on simple cases but it
might pay off for bigger graphs:

--8<---------------cut here---------------start------------->8---
$ GUIX_PROFILING=object-cache ./pre-inst-env guix build hello --target=aarch64-linux-gnu --no-grafts -d
/gnu/store/i8x1gg73x3fvxn4lrrgbcb97sz4qq1yx-hello-2.12.1.drv
Object Cache:
  fresh caches:    20
  lookups:       5514
  hits:          5008 (90.8%)
  cache size:     505 entries
$ # before:
$ GUIX_PROFILING=object-cache ./pre-inst-env guix build hello --target=aarch64-linux-gnu --no-grafts -d
/gnu/store/kdnh9bwg874aq8bvvw9y2vkl7z94icqa-hello-2.12.1.drv
Object Cache:
  fresh caches:    20
  lookups:       5406
  hits:          4907 (90.8%)
  cache size:     498 entries
--8<---------------cut here---------------end--------------->8---

> I think there's other cases (in the llvm and mold modules) where it
> looks like it's called multiple times with the same arguments, so maybe
> that's an argument for having memoization around make-ld-wrapper even
> though it's not needed for all uses.

On guix-devel, Efraim mentioned cargo-build-system packages.  Is that
related?

Thanks for looking into this!

Ludo’.