Dynamically adding debug channels (__wine_dbg_set_channel_flags)

[Daniel Santos]

It would seem quite helpful for debugging odd situations to be able to turn debugging on and off programmatically.  I like not having every debug class loaded in memory by default (and everything that goes with maintaining that global list), but it would seem quite helpful for troubleshooting, testing and debugging special cases (mostly where one doesn't have the sources of the troublesome app).

Thus, perhaps __wine_dbg_set_channel_flags could add the debug channel to debug_options if it doesn't exist and even allow setting the default_flags (say by having a zero-length name in the channel argument) or even another function which would allow it.  I'm not sure what thread synchronization implications this would bring about (and the associated costs of the sync objects), it seems it would require at the least the use of a critical section to modify the debug_options, but perhaps this can be a pre-processor driven option?  The configure could have a --enable-dynamic-channels or some such that would set a pre-processor macro, etc.

Alternatively, a cheaper (hackier) mechanism of thread-safety could be achived by having the debug_options be contained in a struct along with the nb_debug_options and have them heap-allocated so that the debug_options pointer could be changed in a single machine instruction.  A similar mechanism (i.e., hack) could be use to free the old debug_options struct.  That's ugly, but I'm just presenting options.

Daniel

[André Hentschel]

The Problem with a pre-processor setting would be that the endusers may 
not be able to make good logs for the devs.
At the moment you can say to a user "send a log using 
'WINEDEBUG=commctrl wine program.exe'", the user doesnt have to know 
what he is doing exactly, but he sends a usefull text. That wouldnt be 
possible anymore as i understand it.

Best regards André Hentschel

Daniel Santos schrieb:
> It would seem quite helpful for debugging odd situations to be able to 
> turn debugging on and off programmatically.  I like not having every 
> debug class loaded in memory by default (and everything that goes with 
> maintaining that global list), but it would seem quite helpful for 
> troubleshooting, testing and debugging special cases (mostly where one 
> doesn't have the sources of the troublesome app).
>
> Thus, perhaps __wine_dbg_set_channel_flags could add the debug channel 
> to debug_options if it doesn't exist and even allow setting the 
> default_flags (say by having a zero-length name in the channel 
> argument) or even another function which would allow it.  I'm not sure 
> what thread synchronization implications this would bring about (and 
> the associated costs of the sync objects), it seems it would require 
> at the least the use of a critical section to modify the 
> debug_options, but perhaps this can be a pre-processor driven option?  
> The configure could have a --enable-dynamic-channels or some such that 
> would set a pre-processor macro, etc.
>
> Alternatively, a cheaper (hackier) mechanism of thread-safety could be 
> achived by having the debug_options be contained in a struct along 
> with the nb_debug_options and have them heap-allocated so that the 
> debug_options pointer could be changed in a single machine 
> instruction.  A similar mechanism (i.e., hack) could be use to free 
> the old debug_options struct.  That's ugly, but I'm just presenting 
> options.
>
> Daniel
>
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