Arch Linux

Description:

Ok, there is a tricky line in clang/llvm PKGBUILD, here it is:

-------------------------------------------------------------------
# Fix installation directories, ./configure doesn't seem to set them right
sed -i -e 's:\$(PROJ_prefix)/etc/llvm:/etc/llvm:' \
-e 's:\$(PROJ_prefix)/lib:$(PROJ_prefix)/lib/llvm:' \
-e 's:\$(PROJ_prefix)/docs/llvm:$(PROJ_prefix)/share/doc/llvm:' \
Makefile.config.in
-------------------------------------------------------------------

It is supposed to "fix" things, but actually it breaks things.

You see, changing $(PROJ_prefix)/lib to $(PROJ_prefix)/lib/llvm is ok in some cases. But for instance it breaks libclang functionality and c-index-test functionality. Clang itself works fine, because it uses the binary path as a starting point (for some reason):

[nsf @ 2.8]$ clang -print-search-dirs
programs: =/usr/bin:/usr/bin
libraries: =/usr/bin/../lib/clang/2.8/:/lib/:/usr/lib/:/lib32/:/usr/lib32/:/lib64/:/usr/lib64/

If you're interested in that, it can be seen in this source file:
clang-2.8/lib/Driver/Driver.cpp:74

But when we are trying to use c-index-test and libclang (for example some kind of an autocompletion tool based on libclang), we have the following:
(here test.c is a C file that includes stddef.h)

[nsf @ ccode]$ c-index-test -test-inclusion-stack-source -v test.c
... skipped ...
ignoring nonexistent directory "/usr/lib/llvm/../lib/clang/2.8/include"
... skipped ...
test.c:1:10: fatal error: 'stddef.h' file not found

Now it becomes interesting, clang can't see its header (/usr/lib/clang/2.8/include/stddef.h), let's take another look at the source code:
clang-2.8/tools/libclang/CIndexer.cpp:67

Here clang takes the address of the .so file, which has the function 'clang_createTranslationUnit', and on archlinux usually it is:
/usr/lib/llvm/libclang.so

Then it removes library name, and adds "../bin/clang", which results in a wrong path already:
/usr/lib/llvm/../bin/clang

In the next few lines of the source code, it firgures out a resource directory using the path we have above, and you can see that here in the source code:
clang-2.8/tools/libclang/CIndexer.cpp:82

It removes "bin/clang" part and adds instead "lib/clang/2.8" and we have:
/usr/lib/llvm/../lib/clang/2.8

Which then gets transformed into a "/usr/lib/llvm/../lib/clang/2.8/include" and that is the path from an error message of the c-index-test run.



The same stuff works fine on my friend's mac machine. I mean, seriously.. the installation is broken. Maybe clang guys have already fixed that mess with resource directory in the SVN trunk, but I haven't checked. And I have no idea how you can fix that either. But changing that way $(PROJ_prefix)/lib to $(PROJ_prefix)/lib/llvm is not a good idea.