Re: How to build to debug with gdb?

From: Matheus Tavares Bernardino <matheus.bernardino@usp.br>
Date: Aug 27, 2019, 17:55 UTC
Message-ID: <CAHd-oW6MtoYAwv36_Jsx5qQzvLguXdvrA6NRA+D3ayHGmfVSqw@mail.gmail.com>
In-Reply-To: <20190827162725.GA29263@instance-template-2.europe-west6-a.c.vaulted-journal-250706.internal>

On Tue, Aug 27, 2019 at 1:27 PM Giuseppe Crino' <giuscri@gmail.com> wrote:

Show 6 quoted lines

>
> Hello, to debug some issues I built and installed git via
>
> $ make prefix=/usr/local DEVELOPER=1 CFLAGS="-O0 -g"
> $ sudo make install
> $ git --version # git version 2.23.0.40.g4d8aada92f

Hmm, could it be perhaps that CFLAGS is being overwritten? To debug Git with GDB I always add this to my config.mak file:

CFLAGS += -g3 -O0 LDFLAGS += -g3 -O0

And then just compile with `make`. Maybe give it a try?

Show 21 quoted lines

> But it seems there's still some optimization going on that prevents gdb from working correctly.
>
> For example
>
> (gdb) b builtin/config.c:752
> Breakpoint 1 at 0x43942: file builtin/config.c, line 752.
> (gdb) r config --global --edit
> Starting program: /usr/local/bin/git config --global --edit
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/x86_64-linux-gnu/libth
> read_db.so.1".
>
> Breakpoint 1, cmd_config (argc=0, argv=<optimized out>,
>     prefix=<optimized out>) at builtin/config.c:753
>     753                             if (fd >= 0) {
>     (gdb) p fd
>     $1 = <optimized out>
>
>  What am I missing?
>
>  -Giuseppe