On 28/12/2018 19:33, Bruce Dubbs via blfs-support wrote:
On 12/28/2018 11:01 AM, Waleed Hamra via blfs-support wrote:
Hello guys;
I updated my LLVM/Clang from 6.0.1 to 7.0.1, and many things broke.
Including mesa's glx amongst others.
I noticed that I have tons of libraries that specifically depend on
libLLVM-6.0.so, and not on libLLVM.so, which will always point to
whichever is the latest installed version.
On my system, I do see
$ ldd ./libva-glx.so
...
libLLVM-6.0.so => /usr/lib/libLLVM-6.0.so
...
but I still have /usr/lib/libLLVM-6.0.so even though I installed
llvm-7.0.1.
This would happen if you make install directly on top of the previous
installation. In my case, I install to destdir and package them. The
install involves removing all files from the previous package.
I can recompile the affected packages, they're not too many, but I have
a couple of questions first.
I did some limited testing with creating a symlink from libLLVM-6.0.so
into libLLVM.so, and the few programs I tried to run which were linking
to it, ran properly. Can this screw something up later on?
Can I force programs to link against libLLVM.so instead of the versioned
ones? As I was doing my little research, I ran ldd on all my libraries
looking for broken links, and found a bunch that were also linking to
versioned boost libraries. Is there any cmake/configure wizardry to
alter this unfriendly behaviour?
When building, the linker looks at the .so file and uses that symlink to
determine the proper library. It adds a link to the file .so.N to the
target. Then when running, the .so.N file is used. That is generally a
symlink to .so.N.MMM. When updating, the .so.N and .so.N.MMM are not
removed. If the versions are not changed, they are overwritten, but
that means that the API has not changed.
$ ll /usr/lib/libLLVM-*
-rwxr-xr-x 1 43106632 Dec 22 /usr/lib/libLLVM-6.0.so
lrwxrwxrwx 1 14 Oct 8 /usr/lib/libLLVM-6.0.1.so -> libLLVM-6.0.so
-rwxr-xr-x 1 44545224 Dec 22 /usr/lib/libLLVM-7.so
lrwxrwxrwx 1 12 Dec 21 /usr/lib/libLLVM-7.0.1.so -> libLLVM-7.so
-- Bruce
I ended up extracting the llvm and lto libs from the previous package,
and installing them as an llvm6 package. This solved the problem until
the packages needing them are all recompiled in the future. This taught
me to study well before doing any such major version updates.
Thanks a lot Bruce
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