From f51b0d59080b7d0bc897f79f15c28da0cdb564be Mon Sep 17 00:00:00 2001 From: Bob Haarman Date: Wed, 4 Jan 2017 21:40:00 +0000 Subject: [PATCH] [compiler-rt] suppress LNK4221 warning when creating static libraries Summary: We put empty object files in archives, which causes MSVC's linker to complain about these objects not defining any previously undefined symbols. Since we do it on purpose, this only creates noise during the build process. This patch causes us to suppress the warnings. Reviewers: rnk, samsonov Subscribers: dberris, mgorny Differential Revision: https://reviews.llvm.org/D28262 llvm-svn: 291011 --- compiler-rt/CMakeLists.txt | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/compiler-rt/CMakeLists.txt b/compiler-rt/CMakeLists.txt index 5b1591e8a4b5..e8326f04b810 100644 --- a/compiler-rt/CMakeLists.txt +++ b/compiler-rt/CMakeLists.txt @@ -225,6 +225,17 @@ append_list_if(COMPILER_RT_HAS_WD4800_FLAG /wd4800 SANITIZER_COMMON_CFLAGS) # Warnings to turn off for all libraries, not just sanitizers. append_string_if(COMPILER_RT_HAS_WUNUSED_PARAMETER_FLAG -Wno-unused-parameter CMAKE_C_FLAGS CMAKE_CXX_FLAGS) +if (CMAKE_LINKER MATCHES "link.exe$") + # Silence MSVC linker warnings caused by empty object files. The + # sanitizer libraries intentionally use ifdefs that result in empty + # files, rather than skipping these files in the build system. + # Ideally, we would pass this flag only for the libraries that need + # it, but CMake doesn't seem to have a way to set linker flags for + # individual static libraries, so we enable the suppression flag for + # the whole compiler-rt project. + append("/IGNORE:4221" CMAKE_STATIC_LINKER_FLAGS) +endif() + add_subdirectory(include) set(COMPILER_RT_LIBCXX_PATH ${LLVM_MAIN_SRC_DIR}/projects/libcxx)