On Fri, 11 Aug 2017, Itai Berli wrote:

> However, now I get the
> following complaint from gdb:
> 
> > No executable file specified.
> > Use the "file" or "exec-file" command.
That means, gdb doesn't know which program to debug.

> Here's the complete contents of the *gud* buffer.

> Current directory is ~/
> No symbol table is loaded.  Use the "file" command.
> Make breakpoint pending on future shared library load? (y or [n]) y
> Breakpoint 1 (main) pending.
> (gdb) r
> Starting program:  
> No executable file specified.
> Use the "file" or "exec-file" command.
Assuming your executable is at:
~/emacs/src/bootstrap-emacs
you can do in the gdb command line:
file ~/emacs/src/bootstrap-emacs

> On Fri, Aug 11, 2017 at 12:59 PM, Itai Berli <itai.berli@gmail.com> wrote:
>       By the way, the *gud* buffer's first line is
> > Current directory is ~/
> 
> However, the Emacs source code is in ~/emacs. Maybe this is the problem? But I started Emacs from ~/emacs. How can I set
> the *gud* buffer's current directory?
DUNNO why it doesn't starts at ~/emacs.
You can try from a terminal:
|> emacs ~/emacs/src
;; now call gdb
M-x gdb RET ; it should offer to debug 'bootstrap-emacs'