From 501c6fda951b9a50e77ee324015b0b0aea9e2a5b Mon Sep 17 00:00:00 2001 From: nextsilicon-itay-bookstein <55076759+nextsilicon-itay-bookstein@users.noreply.github.com> Date: Mon, 2 Mar 2026 23:10:15 +0200 Subject: [PATCH] [CMake] Propagate dependencies to OBJECT libraries in add_llvm_library (re-land) (#184201) Previously, transitively inherited calls to `target_include_directories(foo SYSTEM ...)` were being squashed into a flat list of includes, effectively stripping off `-isystem` and unintentionally forwarding warnings from such dependencies. To correctly propagate `SYSTEM` dependencies, use `target_link_libraries` to forward the parent target's link dependencies to the OBJECT library (similar to the `_static` flow below). Unlike a flat `target_include_directories`, this lets CMake resolve transitive SYSTEM include directories through the proper dependency chain. Note that `target_link_libraries` on an OBJECT library propagates all usage requirements, not just includes. This also brings in transitive `INTERFACE_COMPILE_DEFINITIONS`, `INTERFACE_COMPILE_OPTIONS`, and `INTERFACE_COMPILE_FEATURES`. This is arguably more correct, as the OBJECT library compiles the same sources and should see the same flags. The existing `target_include_directories` call is retained for include directories set directly on the target (not through link dependencies). CMake deduplicates include directories that appear through both paths. Compile definitions and options may technically appear twice (once via the OBJECT library, once via the consuming target), but duplicate `-D` and flag entries are harmless in practice. Also fix `clang_target_link_libraries` and `mlir_target_link_libraries` to forward the link type (PUBLIC/PRIVATE/INTERFACE) to `obj.*` targets. Previously the type keyword was silently dropped, resulting in plain- signature `target_link_libraries` calls. This is now required because the new keyword-signature call in `llvm_add_library` would otherwise conflict (CMake requires all calls on a target to use the same signature). --- clang/cmake/modules/AddClang.cmake | 2 +- lld/tools/lld/CMakeLists.txt | 2 +- llvm/cmake/modules/AddLLVM.cmake | 29 ++++++++++++++++------------ llvm/cmake/modules/LLVM-Config.cmake | 5 ++++- mlir/cmake/modules/AddMLIR.cmake | 2 +- 5 files changed, 24 insertions(+), 16 deletions(-) diff --git a/clang/cmake/modules/AddClang.cmake b/clang/cmake/modules/AddClang.cmake index c811b7f45912..e2112d7c326e 100644 --- a/clang/cmake/modules/AddClang.cmake +++ b/clang/cmake/modules/AddClang.cmake @@ -217,7 +217,7 @@ endmacro() function(clang_target_link_libraries target type) if (TARGET obj.${target}) - target_link_libraries(obj.${target} ${ARGN}) + target_link_libraries(obj.${target} ${type} ${ARGN}) endif() get_property(LLVM_DRIVER_TOOLS GLOBAL PROPERTY LLVM_DRIVER_TOOLS) diff --git a/lld/tools/lld/CMakeLists.txt b/lld/tools/lld/CMakeLists.txt index 8498a91597a9..1d1a7ff448b7 100644 --- a/lld/tools/lld/CMakeLists.txt +++ b/lld/tools/lld/CMakeLists.txt @@ -13,7 +13,7 @@ export_executable_symbols_for_plugins(lld) function(lld_target_link_libraries target type) if (TARGET obj.${target}) - target_link_libraries(obj.${target} ${ARGN}) + target_link_libraries(obj.${target} ${type} ${ARGN}) endif() get_property(LLVM_DRIVER_TOOLS GLOBAL PROPERTY LLVM_DRIVER_TOOLS) diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake index f59002bc6c83..251fe90e3e83 100644 --- a/llvm/cmake/modules/AddLLVM.cmake +++ b/llvm/cmake/modules/AddLLVM.cmake @@ -6,14 +6,14 @@ include(DetermineGCCCompatible) # get_subproject_title(titlevar) # Set ${outvar} to the title of the current LLVM subproject (Clang, MLIR ...) -# +# # The title is set in the subproject's top-level using the variable # LLVM_SUBPROJECT_TITLE. If it does not exist, it is assumed it is LLVM itself. # The title is not semantically significant, but use to create folders in # CMake-generated IDE projects (Visual Studio/XCode). function(get_subproject_title outvar) if (LLVM_SUBPROJECT_TITLE) - set(${outvar} "${LLVM_SUBPROJECT_TITLE}" PARENT_SCOPE) + set(${outvar} "${LLVM_SUBPROJECT_TITLE}" PARENT_SCOPE) else () set(${outvar} "LLVM" PARENT_SCOPE) endif () @@ -636,7 +636,12 @@ function(llvm_add_library name) # Do add_dependencies(obj) later due to CMake issue 14747. list(APPEND objlibs ${obj_name}) - # Bring in the target include directories from our original target. + # Bring in the target include directories and link info from our original + # target. target_link_libraries propagates transitive dependencies with + # proper SYSTEM include handling from IMPORTED targets. + # target_include_directories propagates include directories set directly on + # the target. + target_link_libraries(${obj_name} PRIVATE $) target_include_directories(${obj_name} PRIVATE $) set_target_properties(${obj_name} PROPERTIES FOLDER "${subproject_title}/Object Libraries") @@ -702,11 +707,11 @@ function(llvm_add_library name) endif() set_target_properties(${name} PROPERTIES FOLDER "${subproject_title}/Libraries") - ## If were compiling with clang-cl use /Zc:dllexportInlines- to exclude inline + ## If were compiling with clang-cl use /Zc:dllexportInlines- to exclude inline ## class members from being dllexport'ed to reduce compile time. ## This will also keep us below the 64k exported symbol limit ## https://blog.llvm.org/2018/11/30-faster-windows-builds-with-clang-cl_14.html - if(LLVM_BUILD_LLVM_DYLIB AND NOT LLVM_DYLIB_EXPORT_INLINES AND + if(LLVM_BUILD_LLVM_DYLIB AND NOT LLVM_DYLIB_EXPORT_INLINES AND MSVC AND CMAKE_CXX_COMPILER_ID MATCHES Clang) target_compile_options(${name} PUBLIC /Zc:dllexportInlines-) if(TARGET ${obj_name}) @@ -1117,7 +1122,7 @@ macro(generate_llvm_objects name) set_property(GLOBAL APPEND PROPERTY LLVM_DRIVER_TOOLS ${name}) set_property(GLOBAL APPEND PROPERTY LLVM_DRIVER_TOOL_ALIASES_${name} ${name}) - target_link_libraries(${obj_name} ${LLVM_PTHREAD_LIB}) + target_link_libraries(${obj_name} PUBLIC ${LLVM_PTHREAD_LIB}) llvm_config(${obj_name} ${USE_SHARED} ${LLVM_LINK_COMPONENTS} ) endif() endif() @@ -1599,8 +1604,8 @@ macro(llvm_add_tool project name) RUNTIME DESTINATION ${${project}_TOOLS_INSTALL_DIR} COMPONENT ${name}) if (LLVM_ENABLE_PDB) - install(FILES $ - DESTINATION "${${project}_TOOLS_INSTALL_DIR}" COMPONENT ${name} + install(FILES $ + DESTINATION "${${project}_TOOLS_INSTALL_DIR}" COMPONENT ${name} OPTIONAL) endif() @@ -1634,8 +1639,8 @@ macro(add_llvm_example name) if( LLVM_BUILD_EXAMPLES ) install(TARGETS ${name} RUNTIME DESTINATION "${LLVM_EXAMPLES_INSTALL_DIR}") if (LLVM_ENABLE_PDB) - install(FILES $ - DESTINATION "${LLVM_EXAMPLES_INSTALL_DIR}" COMPONENT ${name} + install(FILES $ + DESTINATION "${LLVM_EXAMPLES_INSTALL_DIR}" COMPONENT ${name} OPTIONAL) endif() endif() @@ -1673,8 +1678,8 @@ macro(add_llvm_utility name) RUNTIME DESTINATION ${LLVM_UTILS_INSTALL_DIR} COMPONENT ${name}) if (LLVM_ENABLE_PDB) - install(FILES $ - DESTINATION "${LLVM_UTILS_INSTALL_DIR}" COMPONENT ${name} + install(FILES $ + DESTINATION "${LLVM_UTILS_INSTALL_DIR}" COMPONENT ${name} OPTIONAL) endif() diff --git a/llvm/cmake/modules/LLVM-Config.cmake b/llvm/cmake/modules/LLVM-Config.cmake index 96ccf20aa89b..7da7e40f3b0f 100644 --- a/llvm/cmake/modules/LLVM-Config.cmake +++ b/llvm/cmake/modules/LLVM-Config.cmake @@ -106,7 +106,10 @@ function(explicit_llvm_config executable) get_target_property(t ${executable} TYPE) if(t STREQUAL "STATIC_LIBRARY") target_link_libraries(${executable} INTERFACE ${LIBRARIES}) - elseif(t STREQUAL "EXECUTABLE" OR t STREQUAL "SHARED_LIBRARY" OR t STREQUAL "MODULE_LIBRARY") + elseif(t STREQUAL "EXECUTABLE" OR + t STREQUAL "SHARED_LIBRARY" OR + t STREQUAL "MODULE_LIBRARY" OR + t STREQUAL "OBJECT_LIBRARY") target_link_libraries(${executable} PRIVATE ${LIBRARIES}) else() # Use plain form for legacy user. diff --git a/mlir/cmake/modules/AddMLIR.cmake b/mlir/cmake/modules/AddMLIR.cmake index b240aeba2310..60b73876d53f 100644 --- a/mlir/cmake/modules/AddMLIR.cmake +++ b/mlir/cmake/modules/AddMLIR.cmake @@ -769,7 +769,7 @@ endfunction(mlir_check_all_link_libraries) # used. function(mlir_target_link_libraries target type) if (TARGET obj.${target}) - target_link_libraries(obj.${target} ${ARGN}) + target_link_libraries(obj.${target} ${type} ${ARGN}) endif() if (MLIR_LINK_MLIR_DYLIB)