How to run emacs under a debugger on macOS?

How to run emacs under a debugger on macOS?

[Pankaj Jangid]

I haven't done any C/C++ programming on macOS. I am just a user who
connects to remote machines for development. Those who have done it on
macos, please help.

On GNU/Linux, launching a debug build under a debugger is simple "gdb
<binary>". How does Emacs dev community do so on macos? Also tell me how
to make a debug build on macos. Usually I just

make install
test the binary (./src/emacs -Q)
rm -rf /Applications/Emacs.app
cp -r nextstep/Emacs.app /Applications/Emacs.app

In short,
1. How to make debug build?
2. How to launch emacs under a debugger on macos?
3. Any other instructions relevant for debugging.

Regards,
Pankaj

Re: How to run emacs under a debugger on macOS?

[Alan Third]

On Sat, Jan 11, 2020 at 11:32:15AM +0000, Pankaj Jangid wrote:
> I haven't done any C/C++ programming on macOS. I am just a user who
> connects to remote machines for development. Those who have done it on
> macos, please help.
> 
> On GNU/Linux, launching a debug build under a debugger is simple "gdb
> <binary>". How does Emacs dev community do so on macos? Also tell me how
> to make a debug build on macos. Usually I just
> 
> make install
> test the binary (./src/emacs -Q)
> rm -rf /Applications/Emacs.app
> cp -r nextstep/Emacs.app /Applications/Emacs.app
> 
> In short,
> 1. How to make debug build?
> 2. How to launch emacs under a debugger on macos?
> 3. Any other instructions relevant for debugging.

I usually do something like:

    ./configure CFLAGS="-g -O0"
    make
    make install
    lldb nextstep/Emacs.app/Contents/MacOS/Emacs

and in lldb

    run -Q

lldb’s not ideal, though, as it doesn’t support the commands in
src/.gdbinit that make working with lisp structures easier.

It’s possible to use gdb on macOS, but you need to at a minimum sign
it, and upgrades will undo that so you have to do it again. I don’t
usually bother with gdb.

-- 
Alan Third

Re: How to run emacs under a debugger on macOS?

[Yuan Fu]

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I haven’t have much luck with gdb. It doesn’t work for me starting from Mojave. A SO question that describes the symptom:

https://stackoverflow.com/questions/54416996/gdb-on-macos-mojave-10-14-2 <https://stackoverflow.com/questions/54416996/gdb-on-macos-mojave-10-14-2>

Yuan

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Re: How to run emacs under a debugger on macOS?

[Pankaj Jangid]

Alan Third <alan@idiocy.org> writes:

> On Sat, Jan 11, 2020 at 11:32:15AM +0000, Pankaj Jangid wrote:
>> 1. How to make debug build?  2. How to launch emacs under a debugger
>> on macos?  3. Any other instructions relevant for debugging.
>
> I usually do something like:
>
>     ./configure CFLAGS="-g -O0" make make install lldb
>     nextstep/Emacs.app/Contents/MacOS/Emacs

Thanks.

BTW I launched directory from the ./src/emacs after building with "-g
-O0".

> It’s possible to use gdb on macOS, but you need to at a minimum sign
> it, and upgrades will undo that so you have to do it again. I don’t
> usually bother with gdb.

Okay. I'll look into it sometime. :-)

One followup query: Does lldb also create similar dump that the gdb
creates when there is a crash?

Regards
Pankaj

Re: How to run emacs under a debugger on macOS?

[Alan Third]

On Sat, Jan 11, 2020 at 07:00:26PM +0000, Pankaj Jangid wrote:
> Alan Third <alan@idiocy.org> writes:
> 
> > On Sat, Jan 11, 2020 at 11:32:15AM +0000, Pankaj Jangid wrote:
> >> 1. How to make debug build?  2. How to launch emacs under a debugger
> >> on macos?  3. Any other instructions relevant for debugging.
> >
> > I usually do something like:
> >
> >     ./configure CFLAGS="-g -O0" make make install lldb
> >     nextstep/Emacs.app/Contents/MacOS/Emacs
> 
> Thanks.
> 
> BTW I launched directory from the ./src/emacs after building with "-g
> -O0".

Yes, that works fine too.

> One followup query: Does lldb also create similar dump that the gdb
> creates when there is a crash?

Yes. Most of the basic commands in gdb work in lldb too, but not all,
so if you’re being given gdb commands and they don’t work I suggest
you check https://lldb.llvm.org/use/map.html.
-- 
Alan Third

Re: How to run emacs under a debugger on macOS?

[Pankaj Jangid]

Alan Third <alan@idiocy.org> writes:
>> One followup query: Does lldb also create similar dump that the gdb
>> creates when there is a crash?
>
> Yes. Most of the basic commands in gdb work in lldb too, but not all,
> so if you’re being given gdb commands and they don’t work I suggest
> you check https://lldb.llvm.org/use/map.html.

Thanks. Good resource. And I should have searched for it a little
bit. :-|