--with-debug is ignored?

[spolakh]

https://github.com/d12frosted/homebrew-emacs-plus/blob/master/Formula/emacs-plus%4028.rb

it doesn't look like the value of this option affects anything?

I'm trying to debug an emacs 100% cpu hang and am trying to run it with gdb to do it. I've brew uninstall emacs-plus@28ed, and then intsalled with brew install emacs-plus@28 --with-debug --with-native-comp, but when I'm trying to run gdb on it (gdb /usr/local/Cellar/emacs-plus@28/28.0.50/Emacs.app/Contents/MacOS/Emacs), I get

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Reading symbols from Emacs...
(No debugging symbols found in Emacs)

I suspect that the --with-debug option is ignored

[d12frosted]

It is not ignored, and it should be working.

homebrew-emacs-plus/Formula/[email protected]

Line 119 in 7f24428

ENV.append "CFLAGS", "-g -Og" if build.with? "debug"

Could you please build verbosely and share output?

[s-m-t]

'brew install emacs-plus@28 --with-debug --keep-tmp'
or
'./build 28 --with-debug --keep-tmp'

The problem is that clang doesn't actually produce the debugging symbols if you separate the compiling and linking stages as emacs does it just keeps references in the executable to the symbols left in the object files. You have to run dsymutil on the emacs executable to go searching for the object files to produce the dSYM bundle. However, brew will delete those object files before you have a chance to run dsymutil because it considers them temporary files so you have to pass '--keep-tmp'.

further reading if you are interested:
https://stackoverflow.com/questions/32297349/why-does-a-2-stage-command-line-build-with-clang-not-generate-a-dsym-directory?rq=3
https://stackoverflow.com/questions/10044697/where-how-
does-apples-gcc-store-dwarf-inside-an-executable/12827463#12827463
https://wiki.dwarfstd.org/Apple%27s_%22Lazy%22_DWARF_Scheme.md

@d12frosted easy fix might be to automatically pass --keep-tmp if --with-debug is selected. Or possibly have the build script run dsymutil automatically

[d12frosted]

@s-m-t you can try modifying the following line locally to see if it works:

homebrew-emacs-plus/Formula/[email protected]

Line 119 in 7f24428

ENV.append "CFLAGS", "-g -Og" if build.with? "debug"

If that works, let's just pass --keep-tmp and call it a day :)

[swapneils]

I think this might be due to not having the .gdbinit file (or .lldbinit file) from the same source code that Emacs was built from.

Is there any way to make that accessible in the installation directory?
(Also not sure whether those files have a dependency on other parts of the source being available for debugging)