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<div class="moz-cite-prefix">On 01/30/2017 09:09 AM, Hahnfeld, Jonas
via cfe-dev wrote:<br>
</div>
<blockquote
cite="mid:05accfb1a7c04af5b0cee620e8322e88@rwthex-w2-a.rwth-ad.de"
type="cite">
<pre wrap="">Hi,
Background: I'm on CentOS 7 which has GCC 4.8 installed in /usr/bin and I'm
installing Clang to, let's say, /opt/clang. (I'm doing so with
CLANG_DEFAULT_CXX_STDLIB=libc++, just if you wonder why the following
matters to me...)
With the current behavior, -lunwind passed to Clang will pull in the system
default non-GNU /usr/lib/libunwind.so.8. IMO it should take LLVM's version
in /opt/clang/lib/libunwind.so.1
That's why I would like to change the default order for searching libraries
in Clang. Currently (and most probably due to historical reasons), the
Driver adds paths next to GCC first.
I propose to prefer paths next to the installed Clang. You can find the
patch doing the change here: <a class="moz-txt-link-freetext" href="https://reviews.llvm.org/D26244">https://reviews.llvm.org/D26244</a>
However, this has a potential impact as Chandler pointed out in above patch
if Clang is installed to /opt/software together with other software.
With my proposed change, Clang will link against
/opt/software/lib/libunrelated.so when passed -lunrelated whereas before it
had preferred /usr/lib/libunrelated.so (assuming that the library exists in
both places).
Is that considered an important scenario or can we expect our users to
install Clang separately?
Any other feedback on that topic?</pre>
</blockquote>
<br>
I think this is an important usage scenario, but because of the
complication Chandler mentioned, I don't think we can enable it by
default. I think it is very reasonable to have some CMake flag that
enables this behavior.<br>
<br>
-Hal<br>
<br>
<blockquote
cite="mid:05accfb1a7c04af5b0cee620e8322e88@rwthex-w2-a.rwth-ad.de"
type="cite">
<pre wrap="">
Jonas
--
Jonas Hahnfeld, MATSE-Auszubildender
IT Center
Group: High Performance Computing
Division: Computational Science and Engineering
RWTH Aachen University
Seffenter Weg 23
D 52074 Aachen (Germany)
<a class="moz-txt-link-abbreviated" href="mailto:Hahnfeld@itc.rwth-aachen.de">Hahnfeld@itc.rwth-aachen.de</a>
<a class="moz-txt-link-abbreviated" href="http://www.itc.rwth-aachen.de">www.itc.rwth-aachen.de</a>
</pre>
<br>
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<br>
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</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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