emacs-app-devel: problems with native compilation

[pmetzger (Perry E. Metzger)]

If you build the devel version of emacs-app, you start getting lots of messages about -lSystem not being found if you actually try to natively compile anything. Reproducing is quite easy.

[ryandesign (Ryan Carsten Schmidt)]

What do you mean "natively compile"? If the port is failing to build, could you attach the main.log file, please?

[pmetzger (Perry E. Metzger)]

The port builds fine, that's not the problem.

Native compilation is a feature of Emacs as of version 28. Emacs now has a native code compiler for elisp, the extension language that is part of the Emacs system. It works by using libgccjit, although it's not a jit but rather an ahead of time compiler. Emacs will attempt to compile (and cache) basically any elisp it gets invoked on. What happens with the port is Emacs itself starts, but when it attempts to compile elisp code to execute it, it starts spitting out error messages in an internal *Warnings* window. (If you're not an Emacs user, this likely isn't very meaningful to you.)

Regardless, the problem happens with most elisp. For example, with my particular init.elc file:

Warning (initialization): An error occurred while loading ‘/Users/perry/.config/emacs/init.elc’:

Native compiler error: (lambda (arg0 &optional) (let ((f #'yes-or-no-p)) (funcall f arg0))), Compiling /Users/perry/.config/emacs/eln-cache/29_0_50-99cad26e/subr--trampoline-7965732d6f722d6e6f2d70_yes_or_no_p_0.eln...
ld: library not found for -lSystem
collect2: error: ld returned 1 exit status
libgccjit.so: error: error invoking gcc driver
Debugger entered--Lisp error: (native-ice "failed to compile" "/Users/perry/.config/emacs/eln-cache/29_0_50-99cad..." "error invoking gcc driver")
  comp--compile-ctxt-to-file("/Users/perry/.config/emacs/eln-cache/29_0_50-99cad...")
  comp-compile-ctxt-to-file("/Users/perry/.config/emacs/eln-cache/29_0_50-99cad...")
  comp-final1()
  load-with-code-conversion("/private/var/folders/f7/wtf8h98x1wd8sbzw0vrh0d5c00..." "/private/var/folders/f7/wtf8h98x1wd8sbzw0vrh0d5c00..." nil t)
  command-line-1(("-l" "/var/folders/f7/wtf8h98x1wd8sbzw0vrh0d5c0000gq/T/e..."))
  command-line()
  normal-top-level()

You can invoke it in many ways and get similar problems. The consistent error is the stuff about -lSystem not being found.

It's important that those of us who know how to deal with Emacs fix this relatively soon because Emacs 28 will be out relatively soon.

[pmetzger (Perry E. Metzger)]

(Note that other people's builds of the head of the git repo for the Mac, like "emacsformacosx.com", work just fine. It's clearly something we've done in the way we're doing our build.)

[drkp (Dan Ports)]

Yes, I'm seeing that too. Native compilation works fine during the port build but not afterwards.

(Also happens with today's emacs-devel HEAD, FWIW)

[pmetzger (Perry E. Metzger)]

I'm now having trouble building an Emacs on my own that doesn't have this "-lSystem" issue, so I'm interested in what is actually going on here.

BTW, side note, "emacsformacosx.com" carefully packages a bunch of systems libraries in the .app file; we might want to do the same.

[amake (Aaron Madlon-Kay)]

I have been using emacs-app-devel (with +nativecomp) for quite a while and have never seen this issue. Can anyone give specific repro steps?

To be clear, my installation *does* do on-demand compilation of Elisp files, but it always does so successfully.

[pmetzger (Perry E. Metzger)]

You just build an emacs with macports and start it with an init file that loads things that aren't precompiled; it starts spewing messages almost immediately because it can't compile (or run) them.

[wilya7]

Replying to pmetzger:

You just build an emacs with macports and start it with an init file that loads things that aren't precompiled; it starts spewing messages almost immediately because it can't compile (or run) them.

For me to trigger this bug it was enough to use the help system and search for the the documentation of a variable.

[jokuha (Jochen)]

Is there any solution or workaround to this, as it makes Emacs not go through init.el successfully and thus the running instance is not set up/useful.

And -nativecomp leads to a local rebuild (which I will try now, hope ti helps:-o)

[catap (Kirill A. Korinsky)]

After reboot of my machine I've encounter the same issue.

Magically but xcode-select --install seems to fix it.

[diekhans (Mark Diekhans)]

Just started getting this error after an upgrade; is there a definitive way to address it?

[diekhans (Mark Diekhans)]

Ah, bingo; it is doing "xcode-select --install. " My bad; I thought this had been done.

Perhaps the way to code this is to have the emacs require it, or at least warn?