[CMake] Move find_package(ZLIB) to LLVMConfig

[phosek]

Summary

This way, downstream projects don't have to invoke find_package(ZLIB)
reducing the amount of boilerplate.

[compnerd]

Thanks, this is a great idea!

[mehdi_amini]

Thanks!

[stephenneuendorffer]

Perfect! Thanks!

clang/CMakeLists.txt

if( CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR )
   option(LLVM_INSTALL_TOOLCHAIN_ONLY
     "Only include toolchain files in the 'install' target." OFF)
 
   option(LLVM_FORCE_USE_OLD_HOST_TOOLCHAIN
     "Set to ON to force using an old, unsupported host toolchain." OFF)
   option(CLANG_ENABLE_BOOTSTRAP "Generate the clang bootstrap target" OFF)
   option(LLVM_ENABLE_LIBXML2 "Use libxml2 if available." ON)
 
-  if(LLVM_ENABLE_ZLIB)
-    find_package(ZLIB)
-  endif()
-
   include(AddLLVM)
   include(TableGen)
   include(HandleLLVMOptions)
   include(VersionFromVCS)
   include(LLVMDistributionSupport)
 
   set(PACKAGE_VERSION "${LLVM_PACKAGE_VERSION}")
 

lld/CMakeLists.txt

if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   set(PACKAGE_VERSION "${LLVM_PACKAGE_VERSION}")
   include_directories("${LLVM_BINARY_DIR}/include" ${LLVM_INCLUDE_DIRS})
   link_directories(${LLVM_LIBRARY_DIRS})
 
   set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
   set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
   find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH)
 
-  if(LLVM_ENABLE_ZLIB)
-    find_package(ZLIB)
-  endif()
-
   include(AddLLVM)
   include(TableGen)
   include(HandleLLVMOptions)
 
   if(LLVM_INCLUDE_TESTS)
     if(CMAKE_VERSION VERSION_LESS 3.12)
       include(FindPythonInterp)
       if(NOT PYTHONINTERP_FOUND)

lldb/cmake/modules/LLDBStandalone.cmake

 else()
   set(LLVM_SHLIB_OUTPUT_INTDIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
 endif()
 
 # We append the directory in which LLVMConfig.cmake lives. We expect LLVM's
 # CMake modules to be in that directory as well.
 list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
 
-if(LLVM_ENABLE_ZLIB)
-  find_package(ZLIB)
-endif()
-
 include(AddLLVM)
 include(TableGen)
 include(HandleLLVMOptions)
 include(CheckAtomic)
 include(LLVMDistributionSupport)
 
 set(PACKAGE_VERSION "${LLVM_PACKAGE_VERSION}")
 set(LLVM_INCLUDE_TESTS ON CACHE INTERNAL "")

llvm/cmake/modules/LLVMConfig.cmake.in

 
 set(LLVM_ENABLE_TERMINFO @LLVM_ENABLE_TERMINFO@)
 
 set(LLVM_ENABLE_THREADS @LLVM_ENABLE_THREADS@)
 
 set(LLVM_ENABLE_UNWIND_TABLES @LLVM_ENABLE_UNWIND_TABLES@)
 
 set(LLVM_ENABLE_ZLIB @LLVM_ENABLE_ZLIB@)
+if(LLVM_ENABLE_ZLIB)
+  find_package(ZLIB)
+endif()
 
 set(LLVM_LIBXML2_ENABLED @LLVM_LIBXML2_ENABLED@)
 
 set(LLVM_WITH_Z3 @LLVM_WITH_Z3@)
 
 set(LLVM_ENABLE_DIA_SDK @LLVM_ENABLE_DIA_SDK@)
 
 set(LLVM_NATIVE_ARCH @LLVM_NATIVE_ARCH@)

mlir/examples/standalone/CMakeLists.txt

 
 set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/bin)
 set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/lib)
 set(MLIR_BINARY_DIR ${CMAKE_BINARY_DIR})
 
 list(APPEND CMAKE_MODULE_PATH "${MLIR_CMAKE_DIR}")
 list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_DIR}")
 
-if(LLVM_ENABLE_ZLIB)
-  find_package(ZLIB)
-endif()
-
 include(TableGen)
 include(AddLLVM)
 include(AddMLIR)
 include(HandleLLVMOptions)
 
 include_directories(${LLVM_INCLUDE_DIRS})
 include_directories(${MLIR_INCLUDE_DIRS})
 include_directories(${PROJECT_SOURCE_DIR}/include)