Add a CMake variable for -flto

diff --git a/CMakeLists.txt b/CMakeLists.txt
index aff346be0984bd29b892cf29713209ab924e11f7..6bce7ffe383bb4f1d12337248cfd41d2eaadf225 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -51,6 +51,7 @@ set(ICINGA2_RUNDIR "${CMAKE_INSTALL_FULL_LOCALSTATEDIR}/run" CACHE STRING "/run
 set(ICINGA2_PLUGINDIR "/usr/lib/nagios/plugins" CACHE STRING "Path for the check plugins")
 set(ICINGA2_GIT_VERSION_INFO ON CACHE BOOL "Whether to use git describe")
 set(ICINGA2_UNITY_BUILD ON CACHE BOOL "Whether to perform a unity build")
+set(ICINGA2_LTO_BUILD OFF CACHE BOOL "Whether to use LTO")
 
 file(READ "${CMAKE_CURRENT_SOURCE_DIR}/COPYING" ICINGA2_LICENSE_GPL)
 file(READ "${CMAKE_CURRENT_SOURCE_DIR}/COPYING.Exceptions" ICINGA2_LICENSE_ADDITIONS)
@@ -139,6 +140,13 @@ if(CMAKE_C_COMPILER_ID STREQUAL "GNU")
   set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,--gc-sections")
 endif()
 
+if(ICINGA2_LTO_BUILD)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -flto")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -flto")
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -flto")
+  set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -flto")
+endif()
+
 if(MSVC)
   add_definitions(-D_CRT_SECURE_NO_DEPRECATE -D_CRT_NONSTDC_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS)
 endif()

diff --git a/INSTALL.md b/INSTALL.md
index 4e39ee49221f053bb05fb1dc493335266bd3e607..9e6e3fba9cadd7e9089ffff18394c9f35d818698 100644 (file)
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -143,6 +143,7 @@ variables are supported:
 - `ICINGA2_GIT_VERSION_INFO`: Whether to use Git to determine the version number; defaults to `ON`
 - `ICINGA2_COMMAND_GROUP`: The command group Icinga 2 should use; defaults to `icingacmd`
 - `ICINGA2_UNITY_BUILD`: Whether to perform a unity build; defaults to `ON`
+- `ICINGA2_LTO_BUILD`: Whether to use link time optimization (LTO); defaults to `OFF`
 - `ICINGA2_PLUGINDIR`: The path for the Monitoring Plugins project binaries; defaults to `/usr/lib/nagios/plugins`
 - `ICINGA2_RUNDIR`: The location of the "run" directory; defaults to `CMAKE_INSTALL_LOCALSTATEDIR/run`
 - `CMAKE_INSTALL_SYSCONFDIR`: The configuration directory; defaults to `CMAKE_INSTALL_PREFIX/etc`