[LLVMdev] make fails to detect changes in case srcdir != objdir

[Török Edwin]

On 2010-01-05 22:21, David Greene wrote:
> On Tuesday 05 January 2010 13:33, Gregory Petrosyan wrote:
>
>   
>>>>> A non-build after reconfigure is not really a problem.  If nothing in
>>>>> the configuration has changed configure is smart enough not to update
>>>>> anything so make doesn't see any changes.
>>>>>           
>>>> Yes, but in my case support for new targets should be built in.
>>>>         
>>> What do you mean?
>>>       
>> I've done these:
>>
>> 	1) configure --enable-targets=x86
>> 	2) make
>> 	3) configure --enable-targets=all
>> 	4) make
>>
>> and after it I still did not had e.g. C backend.
>>     
>
> Ah.  I actually don't know what configure does in that case.  I suppose
> it depends on what .in files actually use the target list.  This could be
> a real problem, I just don't know enough about the build system to be sure.
>
>   
>>>> It is entirely possible that I've screwed something up, although I've
>>>> tried to follow LLVM docs as closely as possible. LLVM build system is
>>>> really not the nicest part of LLVM :-)
>>>>         
>>> That's true, but that's autoconf's fault, not LLVM's.  :)
>>>       
>> And what was the reason for picking autoconf?
>>     
>
> Don't ask me, it's not what I would have done.  :)
>
> But to be fair, at the time autoconf was really the only game in town.
> Even now, only CMake really competes in this space.
>
> Then again, neither one satisfies Joel Test #2:
>
> http://www.joelonsoftware.com/articles/fog0000000043.html
>
> I've wondered for a long time why software systems don't build a build system
> around a tool that's actually designed for it.  Like make.  In fact I wondered
> so much that I went and did it.  Parallel configure/build/test is a really
> nifty thing.  It's fun seeing regression tests running before the software
> build is complete.  :)
>   

Slightly offtopic, I noticed this project which does something very
similar to what you describe:
http://code.google.com/p/quagmire/

I don't know what its current state is, but is something worth keeping
an eye on IMHO.

Best regards,
--Edwin