From c84c62c50aa8524dbf96217c337f3b5ee4139000 Mon Sep 17 00:00:00 2001 From: Amy Kwan Date: Thu, 21 Nov 2019 23:06:33 -0600 Subject: [PATCH] [CMake] Fix LLVM build non-determinism on RHEL On RHEL, the OS tooling (ar, ranlib) is not deterministic by default. Therefore, we cannot get bit-for-bit identical builds. The goal of this patch is that it adds the flags required to force determinism. Differential Revision: https://reviews.llvm.org/D64817 --- llvm/cmake/modules/HandleLLVMOptions.cmake | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake index b1174f9..9408eb9 100644 --- a/llvm/cmake/modules/HandleLLVMOptions.cmake +++ b/llvm/cmake/modules/HandleLLVMOptions.cmake @@ -135,6 +135,28 @@ if(APPLE) set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -Wl,-flat_namespace -Wl,-undefined -Wl,suppress") endif() +if(${CMAKE_SYSTEM_NAME} MATCHES "Linux") + # RHEL7 has ar and ranlib being non-deterministic by default. The D flag forces determinism, + # however only GNU version of ar and ranlib (2.27) have this option. + # RHEL DTS7 is also affected by this, which uses GNU binutils 2.28 + execute_process(COMMAND ${CMAKE_AR} rD t.a + WORKING_DIRECTORY ${CMAKE_BINARY_DIR} RESULT_VARIABLE AR_RESULT OUTPUT_VARIABLE RANLIB_OUTPUT) + if(${AR_RESULT} EQUAL 0) + execute_process(COMMAND ${CMAKE_RANLIB} -D t.a + WORKING_DIRECTORY ${CMAKE_BINARY_DIR} RESULT_VARIABLE RANLIB_RESULT OUTPUT_VARIABLE RANLIB_OUTPUT) + if(${RANLIB_RESULT} EQUAL 0) + set(CMAKE_C_ARCHIVE_CREATE " Dqc ") + set(CMAKE_C_ARCHIVE_APPEND " Dq ") + set(CMAKE_C_ARCHIVE_FINISH " -D ") + + set(CMAKE_CXX_ARCHIVE_CREATE " Dqc ") + set(CMAKE_CXX_ARCHIVE_APPEND " Dq ") + set(CMAKE_CXX_ARCHIVE_FINISH " -D ") + endif() + file(REMOVE ${CMAKE_BINARY_DIR}/t.a) + endif() +endif() + if(${CMAKE_SYSTEM_NAME} MATCHES "AIX") if(NOT LLVM_BUILD_32_BITS) if (CMAKE_CXX_COMPILER_ID MATCHES "XL") -- 2.7.4