llvm dev - Jun 2015 - [LLVMdev] Long-Term Support for LLVM Projects Extension to Build System?

Dear All,

Thanks for the feedback.

To clarify, this is for LLVM-related projects that are linking against 
the LLVM libraries.

The feature for keeping our source code in arbitrary locations isn't 
something we need.  If we can just drop our source code into 
llvm/projects (or some other designated LLVM subdirectory) and write 
LLVM-esque CMake files, that should be enough for projects that don't 
need to patch the existing LLVM tools.

Regards,

John Criswell


On 6/18/15 9:06 PM, Chandler Carruth wrote:
> On Thu, Jun 18, 2015 at 5:50 PM Hal Finkel <hfinkel at anl.gov 
> <mailto:hfinkel at anl.gov>> wrote:
>
>     This is also related to the metapoint that the cmake build system
>     doesn't glob for source files (or anything else), unlike the
>     makefile build system. This is understandable given the
>     constraints, but we might want to restore some of that
>     functionality for the purpose of supporting out-of-tree projects.
>
>
> I actually think these are completely separate. See below.
>
>
>     What I mean specifically, is that, for example, we could have a
>     normally-empty directory tools/extensions, and
>     tools/CMakeLists.txt could glob for directories in
>     tools/extensions and call add_llvm_tool_subdirectory on all of
>     them. It is true that you'd need to re-run cmake whenever you
>     added something there (we could have a README in that directory to
>     remind people of that), but that seems like a much smaller price
>     than having to maintain a patched version of the upstream sources.
>
>
> We already do this in numerous places. See projects/CMakeLists.txt 
> which does exactly this.
>
> We don't automatically support external projects *in different 
> locations* through globbing, but that's because that doesn't make
any
> sense.
>
> We can add globbing-based recursion to subproject CMake files anywhere 
> it is useful.
>
> There is no problem with globbing to add subdirectories IMO because 
> subdirectories *with new CMake files* clearly have to be introduced 
> and maintained at the points you run the 'cmake' tool. Only
globbing
> for *source files* seems problematic to me at all.
>
> -Chandler
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

-- 
John Criswell
Assistant Professor
Department of Computer Science, University of Rochester
http://www.cs.rochester.edu/u/criswell

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Hi,

If you just want to *link* to LLVM, it is not clear to me why you are not just
relying on LLVM being built separately and have your project CMake pointing to
the llvm build directory and using llvm-config to populate the linker argument?

Best,
— 
Mehdi
> On Jun 19, 2015, at 7:38 AM, John Criswell <jtcriswel at gmail.com>
wrote:
> 
> Dear All,
> 
> Thanks for the feedback.
> 
> To clarify, this is for LLVM-related projects that are linking against the
LLVM libraries.
> 
> The feature for keeping our source code in arbitrary locations isn't
something we need.  If we can just drop our source code into llvm/projects (or
some other designated LLVM subdirectory) and write LLVM-esque CMake files, that
should be enough for projects that don't need to patch the existing LLVM
tools.
> 
> Regards,
> 
> John Criswell
> 
> 
> On 6/18/15 9:06 PM, Chandler Carruth wrote:
>> On Thu, Jun 18, 2015 at 5:50 PM Hal Finkel <hfinkel at anl.gov
<mailto:hfinkel at anl.gov>> wrote:
>> This is also related to the metapoint that the cmake build system
doesn't glob for source files (or anything else), unlike the makefile build
system. This is understandable given the constraints, but we might want to
restore some of that functionality for the purpose of supporting out-of-tree
projects.
>> 
>> I actually think these are completely separate. See below.
>>  
>> 
>> What I mean specifically, is that, for example, we could have a
normally-empty directory tools/extensions, and tools/CMakeLists.txt could glob
for directories in tools/extensions and call add_llvm_tool_subdirectory on all
of them. It is true that you'd need to re-run cmake whenever you added
something there (we could have a README in that directory to remind people of
that), but that seems like a much smaller price than having to maintain a
patched version of the upstream sources.
>> 
>> We already do this in numerous places. See projects/CMakeLists.txt
which does exactly this.
>> 
>> We don't automatically support external projects *in different
locations* through globbing, but that's because that doesn't make any
sense.
>> 
>> We can add globbing-based recursion to subproject CMake files anywhere
it is useful.
>> 
>> There is no problem with globbing to add subdirectories IMO because
subdirectories *with new CMake files* clearly have to be introduced and
maintained at the points you run the 'cmake' tool. Only globbing for
*source files* seems problematic to me at all.
>> 
>> -Chandler
>> 
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu <mailto:LLVMdev at cs.uiuc.edu>        
http://llvm.cs.uiuc.edu <http://llvm.cs.uiuc.edu/>
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
<http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev>
> 
> 
> -- 
> John Criswell
> Assistant Professor
> Department of Computer Science, University of Rochester
> http://www.cs.rochester.edu/u/criswell
<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.cs.rochester.edu_u_criswell&d=AwMD-g&c=8hUWFZcy2Z-Za5rBPlktOQ&r=Mfk2qtn1LTDThVkh6-oGglNfMADXfJdty4_bhmuhMHA&m=4OeKj9B2JjfLUvqRMUSgftUrExBMlakSczNUQb3B5bU&s=D5Q1Ase7UHtkcpB-jO-JMfUNW5BFFSp0eCBvoOMEc70&e=>_______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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On 19 June 2015 at 15:57, Mehdi Amini <mehdi.amini at apple.com> wrote:
> Hi,
>
> If you just want to *link* to LLVM, it is not clear to me why you are not
> just relying on LLVM being built separately and have your project CMake
> pointing to the llvm build directory and using llvm-config to populate the
> linker argument?
>
> Best,
> —
> Mehdi
>
This is what I do in my Pascal compiler project. It may not be the perfect
solution, but I have not found any HUGE drawback yet.

--
Mats
>
> On Jun 19, 2015, at 7:38 AM, John Criswell <jtcriswel at gmail.com>
wrote:
>
>  Dear All,
>
> Thanks for the feedback.
>
> To clarify, this is for LLVM-related projects that are linking against the
> LLVM libraries.
>
> The feature for keeping our source code in arbitrary locations isn't
> something we need.  If we can just drop our source code into llvm/projects
> (or some other designated LLVM subdirectory) and write LLVM-esque CMake
> files, that should be enough for projects that don't need to patch the
> existing LLVM tools.
>
> Regards,
>
> John Criswell
>
>
> On 6/18/15 9:06 PM, Chandler Carruth wrote:
>
>  On Thu, Jun 18, 2015 at 5:50 PM Hal Finkel <hfinkel at anl.gov>
wrote:
>
>> This is also related to the metapoint that the cmake build system
doesn't
>> glob for source files (or anything else), unlike the makefile build
system.
>> This is understandable given the constraints, but we might want to
restore
>> some of that functionality for the purpose of supporting out-of-tree
>> projects.
>>
>
>  I actually think these are completely separate. See below.
>
>
>>
>> What I mean specifically, is that, for example, we could have a
>> normally-empty directory tools/extensions, and tools/CMakeLists.txt
could
>> glob for directories in tools/extensions and call
>> add_llvm_tool_subdirectory on all of them. It is true that you'd
need to
>> re-run cmake whenever you added something there (we could have a README
in
>> that directory to remind people of that), but that seems like a much
>> smaller price than having to maintain a patched version of the upstream
>> sources.
>>
>
>  We already do this in numerous places. See projects/CMakeLists.txt which
> does exactly this.
>
>  We don't automatically support external projects *in different
> locations* through globbing, but that's because that doesn't make
any sense.
>
>  We can add globbing-based recursion to subproject CMake files anywhere
> it is useful.
>
>  There is no problem with globbing to add subdirectories IMO because
> subdirectories *with new CMake files* clearly have to be introduced and
> maintained at the points you run the 'cmake' tool. Only globbing
for
> *source files* seems problematic to me at all.
>
>  -Chandler
>
>
> _______________________________________________
> LLVM Developers mailing listLLVMdev at cs.uiuc.edu        
http://llvm.cs.uiuc.eduhttp://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
> --
> John Criswell
> Assistant Professor
> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.cs.rochester.edu_u_criswell&d=AwMD-g&c=8hUWFZcy2Z-Za5rBPlktOQ&r=Mfk2qtn1LTDThVkh6-oGglNfMADXfJdty4_bhmuhMHA&m=4OeKj9B2JjfLUvqRMUSgftUrExBMlakSczNUQb3B5bU&s=D5Q1Ase7UHtkcpB-jO-JMfUNW5BFFSp0eCBvoOMEc70&e=>
>
>  _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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On 19 June 2015 at 07:57, Mehdi Amini <mehdi.amini at apple.com>
wrote:
> Hi,
>
> If you just want to *link* to LLVM, it is not clear to me why you are not
> just relying on LLVM being built separately and have your project CMake
> pointing to the llvm build directory and using llvm-config to populate the
> linker argument?
This is what I effectively do. Although because I build the projects I
work on I use the CMake config file that LLVM exports to make it
trivially easy to use the LLVM libraries from within CMake (see
http://llvm.org/docs/CMake.html#embedding-llvm-in-your-project).

Thanks,
Dan.