[llvm-dev] RFC: Move cmake shared files

[Paweł Bylica via llvm-dev]

On Wed, Aug 17, 2016 at 1:13 PM John Brawn <John.Brawn at arm.com> wrote:

> > In the build dir the generated files are placed in
> <build-dir>/share/llvm/cmake. After install, in
> <prefix>/lib/llvm/share/llvm/cmake.
>
>
>
> Really? According to this commit
>
>
>
> ------------------------------------------------------------------------
>
> r259821 | olesalscheider | 2016-02-04 20:08:19 +0000 (Thu, 04 Feb 2016) |
> 8 lines
>
>
>
> Install cmake files to lib/cmake/llvm
>
>
>
> This is the right location for platform-specific files.
>
>
>
> On some distributions (e. g. Exherbo), a package can be installed for
> several
>
> architectures in parallel, but the architecture-independent files are
> shared.
>
> Therefore, we must not install architecture-dependent files (like the CMake
>
> config and export files) to share/.
>
> ------------------------------------------------------------------------
>
>
>
> They’re built to <build-dir>/lib/cmake/llvm and installed to
> <prefix>/lib/cmake/llvm, which matches
>
> <prefix>/(lib/<arch>|lib|share)/cmake/<name>*/          (U)
>
> in the cmake documentation you’ve linked.
>
>
>
> (Note: this is trunk, I haven’t looked at 3.x or 4.0)
>
This is good news. But is this layout suitable to support multiple versions
of LLVM?

Libs are installed to <prefix>/lib, but packages changes that to
<prefix>/lib/llvm-X.Y. Should the packaging change also
<prefix>/lib/cmake/llvm to <prefix/lib/cmake/llvm-X.Y. If yes, this might
cause the same issues with hardcoded/incorrectly assumed paths as I'm
having now.


>
> *From:* llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] *On Behalf Of *Pawel
> Bylica via llvm-dev
> *Sent:* 17 August 2016 11:13
> *To:* llvm-dev; Sylvestre Ledru
> *Subject:* [llvm-dev] RFC: Move cmake shared files
>
>
>
> The cmake files generated when building LLVM (including LLVMConfig.cmake)
> are to support cmake's find_package() [1] function.
>
>
>
> In the build dir the generated files are placed in
> <build-dir>/share/llvm/cmake. After install, in
> <prefix>/lib/llvm/share/llvm/cmake.
>
>
>
> CMake is not able to find them without a hint. CMake searches these paths
> on Unix:
>
> - <prefix>/lib/llvm/cmake
>
> - <prefix>/share/llvm/cmake
>
>
>
> Some distributions try to workaround the problem by moving contents of
> /lib/llvm/share/llvm/cmake to /share/llvm/cmake, but usually that breaks
> the configuration included in LLVMConfig.cmake because of some hardcoded
> paths there.
>
>
>
> I propose to move the generated files to <build-dir>/cmake and install
> them to <prefix>/lib/llvm/cmake.
>
>
>
> This should also help on Windows, where CMake searches in
> <prefix>/llvm/cmake.
>
>
>
> - Paweł
>
>
>
> [1] https://cmake.org/cmake/help/v3.0/command/find_package.html
>
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