need of SOFTWARE_SINGLE_STEP

need of SOFTWARE_SINGLE_STEP

[debashis mahata]

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Hi,
I am 
just a new comer in GDB internals. I have a doubt regarding the necessity of 
SOFTWARE_SINGLE_STEP in the function resume() (file: infrun.c). My working 
platform is Sparc- Solaris 5.8 and going through the code of GDB 4.18. The 
question is :
 
The 
file procfs.c have the support for single step using the PRSTEP flag (function: 
proc_run_process() ). Then, is there any specific reason behind doing 
SOFTWARE_SINGLE_STEP rather than using the proc system support? Will there be 
any hidden side effect if I disabled SOFTWARE_SINGLE_STEP_P and use PRSTEP for 
single stepping?
 
Looking forward to an early response.  
Thanks 
in advance.
mahata.

Re: need of SOFTWARE_SINGLE_STEP

[Daniel Berlin]

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"debashis  mahata" <debashis.mahata@wipro.com> writes:

> Hi,
> 
> I am just a new comer in GDB internals. I have a doubt regarding the necessity
> of SOFTWARE_SINGLE_STEP in the function resume() (file: infrun.c). My working
> platform is Sparc- Solaris 5.8 and going through the code of GDB 4.18. The
> question is :
> 
>  
> 
> The file procfs.c have the support for single step using the PRSTEP flag
> (function: proc_run_process() ). Then, is there any specific reason behind
> doing SOFTWARE_SINGLE_STEP rather than using the proc system
> support?
The fact that many host OSes of GDB have no procfs support?
>  Will
> there be any hidden side effect if I disabled SOFTWARE_SINGLE_STEP_P and use
> PRSTEP for single stepping?
Yes, you'll break GDB on a lot of platforms.
:)

> 
>  
> 
> Looking forward to an early response. 
> 
> Thanks in advance.
> 
> mahata.

-- 
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Twenty people were trapped on the escalators.
"-Steven Wright

Re: need of SOFTWARE_SINGLE_STEP

[J.T. Conklin]

>>>>> "debashis" == debashis mahata <debashis.mahata@wipro.com> writes:
debashis> I am just a new comer in GDB internals. I have a doubt
debashis> regarding the necessity of SOFTWARE_SINGLE_STEP in the
debashis> function resume() (file: infrun.c). My working platform is
debashis> Sparc- Solaris 5.8 and going through the code of GDB
debashis> 4.18. The question is :

If I recall correctly, kernel single-step support is a relatively new
feature in Solaris.  If you know that you'll only run GDB on versions
that support it, you probably can get away with disabling SOFTWARE_-
SINGLE_STEP_P locally.  I'm not sure what would be required to get it
into the mainline GDB.  It would either have to be a new config, or 
be able to determine whether or not kernel single-step is available
at run-time.

        --jtc

-- 
J.T. Conklin
RedBack Networks