bug#34235: 27.0.50; lisp profiler does not work

[Eli Zaretskii <eliz@gnu.org>]

> From: Alex Branham <alex.branham@gmail.com>
> Date: Mon, 28 Jan 2019 12:34:03 -0600
> 
> The lisp profiler (i.e. M-x profiler-start, M-x profiler-report, etc)
> seems to not work for me since the pdumper got merged (or sometime
> around then). I'm not using --enable-profiling when I run ./configure.
> 
> emacs -q
> M-x profiler-start (set cpu mode)
> C-x C-f ~/.emacs.d/init.el
> M-x profiler-report
> 
> results in the profiler report buffer only having the contents:
> 
> - ...                                                               1 100%
>    Automatic GC                                                     1 100%
> 
> but surely there should be more in there. More generally, it doesn't
> seem to ever report anything for me, no matter how long I leave it
> running for. I've got no idea if the pdumper has anything to do with
> this, it just seems to have been happening since about then.

I couldn't reproduce this with today's master branch.  I tried on
GNU/Linux and on 2 different MS-Windows machines, and profiling worked
for me on all of them.  I see much more than just "Automatic GC".

So I suggest that you look into possible local changes on your system
recently, and perhaps also try the emacs-26 branch (where there's no
pdumper).

For the record, after invoking profiler-start in CPU mode, I visited
xdisp.c and typed M->, then invoked profiler-report, and typed "C-u RET"
on every "+" sign in the leftmost column.  Did you do something similar?

Thanks.