CTF patch for testing/review (was: Re: is dtrace usable?)

[Scott Long]

On Mar 22, 2010, at 7:41 AM, John Baldwin wrote:
> On Monday 22 March 2010 7:34:08 am Alexander Leidinger wrote:
>> Redirecting from stable@ to arch at ...
>> 
>> Quoting John Baldwin <jhb at freebsd.org> (from Wed, 10 Mar 2010 08:12:29 
> -0500):
>> 
>>> On Wednesday 10 March 2010 5:34:22 am Alexander Leidinger wrote:
>>>> Quoting "Robert N. M. Watson" <rwatson at freebsd.org> (from Tue, 9 Mar
>>>> 2010 16:39:09 +0000):
>>>> 
>>>>> 
>>>>> On Mar 9, 2010, at 2:16 PM, Alexander Leidinger wrote:
>>>>> 
>>>>>>> From this you can see that sys.mk is included and parsed before
>>> 'Makefile',
>>>>>>> so the WITH_CTF=yes is not set until after sys.mk has been parsed.
>>>>>> 
>>>>>> I think we need to find a different solution for this. The need to
>>>>>> specify WITH_CTF at the command line is very error prone. :(
>>>>> 
>>>>> You are neither the first person to have made this observation, nor
>>>>> the first person to have failed to propose a solution in the form of
>>>>> a patch :-).
>> 
>> Ok, here is the proposal in form of a patch. :-)
>>     http://www.leidinger.net/test/ctf.diff
>> 
>>> Unfortunately the ctf stuff breaks static binaries.  I think that if  
>>> that were
>>> fixed we would simply enable it by default and be done.
>> 
>> The patch is:
>>  - enabling CTF stuff by default for the kernel
>>  - allows to disable the CTF stuff for the kernel by defining NO_CTF
>>  - *not* enabling the CTF stuff by default for libs and progs
>>    (if someone tells me how to distinguish the build for static
>>    stuff from dynamic stuff, I can have a look to enable it for
>>    the dynamic case)
>>  - allows to enable the CTF stuff for the userland by defining
>>    WITH_CTF as before
> 
> I think this patch looks very interesting.  I think in some ways it would be 
> nice to make CTF "opt-in" though instead of "opt-out".  I think the current 
> patch would enable CTF when building ports, for example.   I think instead it 
> should default to not building CTF, but require an ENABLE_CTF (instead of 
> NO_CTF) to be set, and set that in bsd.kern.mk if WITH_CTF is defined.
> 

I have a patch at Yahoo that makes WITH_CTF settable from the kernel config file, thus making it opt-in.  I'd prefer this as well to opt-out.  Give me a little bit to dig it up and polish it for review.

Scott