[PATCH] D40779: [cmake] Fix zlib library detection

[Rafael Avila de Espindola via llvm-commits]

When building static I am getting

HAVE_LIBZ_Z:INTERNAL=1

and --system-libs shows

-lz -lrt -ldl -lpthread -lm

So I think it is working.

Thanks,
Rafael

Pavel Labath via Phabricator <reviews at reviews.llvm.org> writes:

> labath created this revision.
> Herald added a subscriber: mgorny.
>
> A couple of people were broken by the previous zlib patch. It turned out
> this was because I used find_libraries for searching for the z library.
> This returns absolute paths, and when these paths made it into
> llvm-config, it made it produce nonsensical flags for the --system-libs
> output. To fix this, I hand-roll a search for the library in the same
> way that we search for the terminfo library a couple of lines below.
>
> This is a bit less flexible than the find_library option, as it does not
> allow the user to specify the path to the library at configure time
> (which is important on windows, as zlib is unlikely to be found in any
> of the standard places cmake searches), but I was able to guide the
> build to find it with appropriate values of LIB and INCLUDE environment
> variables.
>
>
> https://reviews.llvm.org/D40779
>
> Files:
>   cmake/config-ix.cmake
>   lib/Support/CMakeLists.txt
>
>
> Index: lib/Support/CMakeLists.txt
> ===================================================================
> --- lib/Support/CMakeLists.txt
> +++ lib/Support/CMakeLists.txt
> @@ -1,6 +1,6 @@
>  set(system_libs)
>  if ( LLVM_ENABLE_ZLIB AND HAVE_LIBZ )
> -  set(system_libs ${system_libs} ${ZLIB_LIBRARY_PATH})
> +  set(system_libs ${system_libs} ${ZLIB_LIBRARIES})
>  endif()
>  if( MSVC OR MINGW )
>    # libuuid required for FOLDERID_Profile usage in lib/Support/Windows/Path.inc.
> Index: cmake/config-ix.cmake
> ===================================================================
> --- cmake/config-ix.cmake
> +++ cmake/config-ix.cmake
> @@ -130,11 +130,17 @@
>  # Don't look for these libraries if we're using MSan, since uninstrumented third
>  # party code may call MSan interceptors like strlen, leading to false positives.
>  if(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
> -  find_library(ZLIB_LIBRARY_PATH NAMES z zlib)
> -  if (LLVM_ENABLE_ZLIB AND ZLIB_LIBRARY_PATH)
> -    check_library_exists(${ZLIB_LIBRARY_PATH} compress2 "" HAVE_LIBZ)
> -  else()
> -    set(HAVE_LIBZ 0)
> +  set(HAVE_LIBZ 0)
> +  if(LLVM_ENABLE_ZLIB)
> +    foreach(library z zlib_static zlib)
> +      string(TOUPPER ${library} library_suffix)
> +      check_library_exists(${library} compress2 "" HAVE_LIBZ_${library_suffix})
> +      if(HAVE_LIBZ_${library_suffix})
> +        set(HAVE_LIBZ 1)
> +        set(ZLIB_LIBRARIES "${library}")
> +        break()
> +      endif()
> +    endforeach()
>    endif()
>  
>    # Don't look for these libraries on Windows.
>
>
> Index: lib/Support/CMakeLists.txt
> ===================================================================
> --- lib/Support/CMakeLists.txt
> +++ lib/Support/CMakeLists.txt
> @@ -1,6 +1,6 @@
>  set(system_libs)
>  if ( LLVM_ENABLE_ZLIB AND HAVE_LIBZ )
> -  set(system_libs ${system_libs} ${ZLIB_LIBRARY_PATH})
> +  set(system_libs ${system_libs} ${ZLIB_LIBRARIES})
>  endif()
>  if( MSVC OR MINGW )
>    # libuuid required for FOLDERID_Profile usage in lib/Support/Windows/Path.inc.
> Index: cmake/config-ix.cmake
> ===================================================================
> --- cmake/config-ix.cmake
> +++ cmake/config-ix.cmake
> @@ -130,11 +130,17 @@
>  # Don't look for these libraries if we're using MSan, since uninstrumented third
>  # party code may call MSan interceptors like strlen, leading to false positives.
>  if(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
> -  find_library(ZLIB_LIBRARY_PATH NAMES z zlib)
> -  if (LLVM_ENABLE_ZLIB AND ZLIB_LIBRARY_PATH)
> -    check_library_exists(${ZLIB_LIBRARY_PATH} compress2 "" HAVE_LIBZ)
> -  else()
> -    set(HAVE_LIBZ 0)
> +  set(HAVE_LIBZ 0)
> +  if(LLVM_ENABLE_ZLIB)
> +    foreach(library z zlib_static zlib)
> +      string(TOUPPER ${library} library_suffix)
> +      check_library_exists(${library} compress2 "" HAVE_LIBZ_${library_suffix})
> +      if(HAVE_LIBZ_${library_suffix})
> +        set(HAVE_LIBZ 1)
> +        set(ZLIB_LIBRARIES "${library}")
> +        break()
> +      endif()
> +    endforeach()
>    endif()
>  
>    # Don't look for these libraries on Windows.