patches/0014-rocksb-inherit-parent-cmake-cxx-flags.patch

   1 From 620b68a348f07145c49c12668576a89dee8198cb Mon Sep 17 00:00:00 2001
   2 From: Kefu Chai <tchaikov@gmail.com>
   3 Date: Fri, 15 Dec 2023 19:01:46 +0800
   4 Subject: [PATCH] cmake/modules/BuildRocksDB.cmake: inherit parent's CMAKE_CXX_FLAGS
   5
   6 CMake allows us to customize `CMAKE_CXX_FLAGS` by setting CXXFLAGS
   7 environmental variable. and Debian's debhelper also sets CXXFLAGS
   8 when it builds cmake projects for customizing the building flags.
   9
  10 but we fail to populate this setting down when building external
  11 projects. this is important when it comes to the projects which
  12 is critical to the performance. RocksDB is one of them.
  13
  14 in this change, we pass the `CMAKE_CXX_FLAGS` down in
  15 `BuildRocksDB.cmake` so that its `CMAKE_CXX_FLAGS` contains
  16 the same set of `CMAKE_CXX_FLAGS` used by its parent project.
  17
  18 this should help with the performance in the bluestore, where
  19 RocksDB is used.
  20
  21 Signed-off-by: Kefu Chai <tchaikov@gmail.com>
  22  [TL: squashed in "cmake/modules/BuildRocksDB.cmake: use string(APPEND
  23   ..) when appropriate" ]
  24 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
  25 ---
  26  cmake/modules/BuildRocksDB.cmake | 4 ++--
  27  cmake/modules/BuildRocksDB.cmake | 1 +
  28  2 files changed, 3 insertions(+), 2 deletions(-)
  29
  30 diff --git a/cmake/modules/BuildRocksDB.cmake b/cmake/modules/BuildRocksDB.cmake
  31 index f9a28274c40..e0208f6545b 100644
  32 --- a/cmake/modules/BuildRocksDB.cmake
  33 +++ b/cmake/modules/BuildRocksDB.cmake
  34 @@ -52,12 +52,13 @@ function(build_rocksdb)
  35    endif()
  36    include(CheckCXXCompilerFlag)
  37    check_cxx_compiler_flag("-Wno-deprecated-copy" HAS_WARNING_DEPRECATED_COPY)
  38 +  set(rocksdb_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
  39    if(HAS_WARNING_DEPRECATED_COPY)
  40 -    set(rocksdb_CXX_FLAGS -Wno-deprecated-copy)
  41 +    string(APPEND rocksdb_CXX_FLAGS " -Wno-deprecated-copy")
  42    endif()
  43    check_cxx_compiler_flag("-Wno-pessimizing-move" HAS_WARNING_PESSIMIZING_MOVE)
  44    if(HAS_WARNING_PESSIMIZING_MOVE)
  45 -    set(rocksdb_CXX_FLAGS "${rocksdb_CXX_FLAGS} -Wno-pessimizing-move")
  46 +    string(APPEND rocksdb_CXX_FLAGS " -Wno-pessimizing-move")
  47    endif()
  48    if(rocksdb_CXX_FLAGS)
  49      list(APPEND rocksdb_CMAKE_ARGS -DCMAKE_CXX_FLAGS='${rocksdb_CXX_FLAGS}')