[compiler-rt] r215247 - [CMake] Determine which compiler-rt librariesare supported on

Alexey Samsonov vonosmas at gmail.com
Wed Aug 20 10:22:41 PDT 2014


Got it, thanks for clarifications. I've submitted r216083 which adds
CMAKE_EXE_LINKER_FLAGS to try_compile test. Let me know if it fixes a
problem for you.


On Wed, Aug 20, 2014 at 12:05 AM, Andy Gibbs <andyg1001 at hotmail.co.uk>
wrote:

>   *From:* Alexey Samsonov <vonosmas at gmail.com>
> *Sent:* Monday, August 18, 2014 9:58 PM
> *Subject:* Re: [compiler-rt] r215247 - [CMake] Determine which
> compiler-rt librariesare supported on
>
> On Sat, Aug 16, 2014 at 2:33 PM, Andy Gibbs <andyg1001 at hotmail.co.uk>
> wrote:
>
>> On Saturday, August 09, 2014 12:01 AM, Alexey Samsonov wrote:
>>
>>> Author: samsonov
>>> Date: Fri Aug  8 17:01:20 2014
>>> New Revision: 215247
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=215247&view=rev
>>> Log:
>>> [CMake] Determine which compiler-rt libraries are supported on
>>> a given platform in a top-level CMakeLists.txt to use it both
>>> in lib/ and in test/ subdirectories. Move architecture/platform
>>> checks to config-ix.
>>>
>>
>> Unfortunately your patch breaks builds where special linker flags are
>> used: "try_compile" fails since the user-specified linker flags are
>> overridden.
>>
>
>  Did the build work before the patch? I didn't change the try_compile
> function, just moved it to separate file. What platform/arch are you
> building for? Your patch is probably ok, just making sure I understand the
> cause of the breakage.
>
> Hmm, you're right.  Plus I'd isolated the wrong patch anyway since I'm
> building from the 3.5 branch and this branched before this patch was
> committed.  I can't say exactly when the breakage happened, since the
> previous fully working version I have is the 3.4 release and since then I
> have only tracked trunk sporadically.  Interestingly, the change to the
> try_compile function was before the 3.4 branch, so it must be some other
> change that has highlighted the problem.  In order to get a correct build
> for llvm, I have to run cmake twice, first with linker flags as part of
> CMAKE_CXX_FLAGS then separated out into CMAKE_*_LINKER_FLAGS.  The first
> pass always, and still always, completes successfully.  The second pass now
> fails with an unable to compile error (missing library).  I imagine
> somewhere a change has been made to re-evaluate this part of the
> configuration, causing the failure.  The simple solution, therefore, is
> simply to pass the linker flags on.
>
> Apologies for the incorrect first assessment.
>
> Cheers
> Andy
>
>
>



-- 
Alexey Samsonov
vonosmas at gmail.com
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