"Debugging" means many things. Python is built with -Og because it
makes Python faster than -O0, and most developers debug Python code,
not C code (in gdb).

If you don't need to go up to the gdb/lldb level, -Og is fine.

It would even make sense to build Python with -O3 in debug mode if you
don't debug C code at all, only pure Python code.

My proposition to switch to -00 by default was rejected:
https://bugs.python.org/issue38350

I also love -O0 when I modify C code because it makes the build faster ;-)

Fedora Python debug builds are now built with -O0 which makes gdb a
way more pleasant experience, not more strange behavior with inlined
code or "<optimized out>" local variables or function arguments.

Victor

On Sun, May 23, 2021 at 3:57 PM Skip Montanaro <skip.montan...@gmail.com> wrote:
>
> > I strongly suggest to only build Python with -O0 when using gdb. -Og
> > enables too many optimizations which makes gdb less usable.
>
> Thanks, Victor. It never made sense to me that you would want any
> optimizations enabled when truly debugging code (as opposed to wanting
> debug symbols and a sane traceback in production code).
>
> I'm getting more convinced that the problem I'm seeing is a GCC/GDB
> thing, particularly because I can move the erroneous stopping point by
> changing the GCC optimization level. I'll probably open a bugzilla
> report just so it's on that team's radar screen. In the meantime, to
> get going again I wrote a crude script which maps the
> file:function:label form to file:linenumber form. That way I can
> save/restore breakpoints across GDB sessions and still avoid problems
> when the offsets to specific instructions change.
>
> Skip
>
> Skip



-- 
Night gathers, and now my watch begins. It shall not end until my death.
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