Speed up gdb loading

[Ralf Habacker]

Am 02.08.21 um 18:23 schrieb Da Viper:
> Hello there I am currently do so,
>
> But I have a problem with using python2,
>
> It does not work for some classes in an ide but I cannot figure out why,
>
> I have updated the read me to add python 2
>
> You have to import qtprinters_py2 to use python2
Comparing this new file with printer.py, I see that one major difference 
is the usage of the brand new python 3.6 feature named f-string,

     def to_string(self) -> str:
         ucs = self.val['ucs']

         return f"{ucs} '{chr(ucs)}'"

where the python 2 style

     def to_string(self):
         ucs = self.val['ucs']
         return "%d '%s'" % (ucs, chr(ucs))

also works with python3.

Another difference is the int()/long() differences, for which a major 
version independent recipe is available:

if sys.version_info[0] > 2:
     # int subsumes long
     long = int

...

in code the use long() regardless of major version

See 
https://github.com/gcc-mirror/gcc/blob/16e2427f50c208dfe07d07f18009969502c25dc8/libstdc%2B%2B-v3/python/libstdcxx/v6/printers.py#L46 
for further compatibility hints.

https://python-future.org/compatible_idioms.html also provides hints for 
how to write python 2 and 3 compatible code.


> SCENARIO:
>
> For example we have a qfile
>
> `QFile file("/some/file/path");`
>
> if I go to the command line gdb to print it, it works correctly,
you used the version from the mentioned kmymoney snapshots ?
>
> but when I try it within the IDE it crashes.
> I think it has to do with the long type when reading the memory of the 
> QFile  in python2 but I am not sure. I tried using int() for the 
> address. But It is too large.
>
> Is there a way to know what the actual problem is because it just 
> crashes without any traceback.

Many applications on Windows uses the windows debug port, which can be 
inspected by dbgview (search on google), which needs to be started in 
front of the application in question.

If that does not help, running the IDE from command line gdb or 
attaching gdb to the running IDE after it has been started should give 
you at least tracebacks in case an exception or segment violation occured.

If that does not help adding print statements to your python code to see 
which line is working and which not, may give you some insights. 
Printing the value of variables can also help. Also installing a trace 
function may help, see for https://pymotw.com/2/sys/tracing.html, which 
may give detailled output, but I haven't tried yet.

Debugging the IDE application may also be an option, but this needs some 
investigation, how the IDE implemented the debugging (does it call an 
external debugger or it that provided by the same process) and where the 
issue happens (inside the debugger or inside the IDE). It also requires 
debug symbols for the IDE application.

Regards

Ralf

>
> On Mon, 2 Aug 2021, 09:15 Ralf Habacker via Kde-finance-apps, 
> <kde-finance-apps at kde.org <mailto:kde-finance-apps at kde.org>> wrote:
>
>     Am 20.07.21 um 10:23 schrieb Ralf Habacker via Kde-finance-apps:
>     > Hi Ebuka,
>     >
>     > I remembered you mentioning the long loading time of gdb when debug
>     > symbols are installed.
>     >
>     I recognized that the recent gdb version 10.2 speeds up symbol
>     loading on Windows, see
>
>     https://lists.gnu.org/archive/html/info-gnu/2021-04/msg00006.html
>     <https://lists.gnu.org/archive/html/info-gnu/2021-04/msg00006.html>
>     * Improved performance during startup through the use of threading
>     during symbol table loading (an optional feature in GDB 9, now
>     enabled by default in GDB 10).
>
>     You may verify this with a recent kmymoney snapshot from
>     https://kmymoney.org/snapshots.php#kmymoney5-aq6
>     <https://kmymoney.org/snapshots.php#kmymoney5-aq6>, which now
>     contains gdb 10.2.
>
>     If you want a standalone gdb package that is independent of
>     kmymoney and better suited for testing with your gdb printer GSOC
>     project, you can check
>     https://kmymoney.org/snapshots.php#gdb-snapshot
>     <https://kmymoney.org/snapshots.php#gdb-snapshot>.
>
>     Regards
>     Ralf
>
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