[Qt-creator] Remote GDB debugging.

[Poenitz Andre]

Tim Hutt wrote:
> I don't really understand why I have to specify a debugger,
> and therefore what to use as a debugger. As I understand it,
> the Segger J-Link GDB server listens on a TCP port (2331),
>  and I gave QtCreator that port, so now it can just connect to 
> it and send GDB commands right? 

No. GDB_server_ does not understand GDB ("client") commands.
That's two completely different protocols.

> Why would it need a GDB executable?

Creator talks to GDB (which uses Python as internal scripting
language) that's configured for your target, and this GDB talks 
to a GDB server (or something else that speaks the same 
protocol).

> In any case, I tried the gdb which came with the GNU Arm
> Embedded compiler I am using. Apparently it doesn't support 
> python so I can't use it. 

Generally you can build GDB yourself from source, Get sources 
e.g. from git://sourceware.org/git/gdb.git, make sure to have 
Python development package in reach, and ./configure
--target=arm-none-linux-gnueabi

On Windows it's a bit more involved, take a look at 
dist/gdb/Makefile.mingw in your Qt Creator sources.

> I also tried the MingW GDB which came with the Qt SDK. 
> That at least starts.

That GDB build understands your local Windows .exe's, 
it doesn't know anything about ARM targets.

> None of this makes any sense.

...

> And as for the Run settings. I am only given one option and there is 
> no way around it. If I press the debug button with no executable set,
> it shows the dialog below:

That's not surprising, as you try to start a local executable.

> It seems to work best if I set the executable to my "foo.out" file - 
> at least then the GDB sessions says the breakpoints are synchronised 
> (when I'm using the Qt SDK version of GDB - not the Arm Embedded one).

> But then it tries to send `run c:\Users\me\blah\blah\foo.out` in 
> gdb and that obviously doesn't work.

...

> It would really help if you could post screen-shots of your Kits, 
> Debuggers, Compilers and Run settings!!

On not-so-recent Ubuntu with yesterdays Creator from "master" 
branch I have for an STM32F4 board the following setup:

- in the Bare Metal device set up:
Gdb host: |/usr/local/bin/openocd -c "gdb_port pipe" -c "log_output openocd.log;" -f board/stm32f4discovery.cfg
Gdb port: 3333
Gdb commands: set remote hardware-breakpoint-limit 6  \
 set remote hardware-watchpoint-limit 4 \
 monitor reset halt \  load \  monitor reset halt

- in the Build and Run/Debugger page an entry pointing to
/data/dev/debugger/gdb-git-arm-none-eabi-install/bin/arm-none-eabi-gdb
(which is a self-build GDB as described above)

- in the Build and Run/Compiler page an entry pointing to
/usr/bin/arm-none-eabi-g++

- in the Build and Run/Kits page an entry combining those
(BareMetal device, the debugger, and the compiler)

Once the tool chain is set up and Tim's example project from
https://gitorious.org/mbed-for-baremetal-qtcreator is loaded
pressing "Run" gives me a nicely blinking LED within 3 seconds.

Andre'