From 65fc11a49ec939261ca9a3dbfa534a9c3354825e Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sun, 8 Jun 2014 16:13:17 +0200
Subject: Add ENABLE_LTO cmake option

Tested with GCC and clang; unlikely to work with other toolchains, so it's
disabled by default.
---
 cmake/CMakeFindBinUtils.cmake |  8 +++++---
 cmake/checks.cmake            | 15 +++++++++++++++
 cmake/config.cmake            |  2 ++
 3 files changed, 22 insertions(+), 3 deletions(-)

(limited to 'cmake')

diff --git a/cmake/CMakeFindBinUtils.cmake b/cmake/CMakeFindBinUtils.cmake
index 83d1a4e..753577a 100644
--- a/cmake/CMakeFindBinUtils.cmake
+++ b/cmake/CMakeFindBinUtils.cmake
@@ -1,5 +1,7 @@
-find_program(CMAKE_AR NAMES ${_CMAKE_TOOLCHAIN_PREFIX}gcc-ar HINTS ${_CMAKE_TOOLCHAIN_LOCATION})
-find_program(CMAKE_NM NAMES ${_CMAKE_TOOLCHAIN_PREFIX}gcc-nm HINTS ${_CMAKE_TOOLCHAIN_LOCATION})
-find_program(CMAKE_RANLIB NAMES ${_CMAKE_TOOLCHAIN_PREFIX}gcc-ranlib HINTS ${_CMAKE_TOOLCHAIN_LOCATION})
+if(CMAKE_COMPILER_IS_GNUCC)
+  find_program(CMAKE_AR NAMES ${_CMAKE_TOOLCHAIN_PREFIX}gcc-ar HINTS ${_CMAKE_TOOLCHAIN_LOCATION})
+  find_program(CMAKE_NM NAMES ${_CMAKE_TOOLCHAIN_PREFIX}gcc-nm HINTS ${_CMAKE_TOOLCHAIN_LOCATION})
+  find_program(CMAKE_RANLIB NAMES ${_CMAKE_TOOLCHAIN_PREFIX}gcc-ranlib HINTS ${_CMAKE_TOOLCHAIN_LOCATION})
+endif(CMAKE_COMPILER_IS_GNUCC)
 
 include(${CMAKE_ROOT}/Modules/CMakeFindBinUtils.cmake)
diff --git a/cmake/checks.cmake b/cmake/checks.cmake
index 225c443..62d10d0 100644
--- a/cmake/checks.cmake
+++ b/cmake/checks.cmake
@@ -9,6 +9,21 @@ if(ARCH_X86 OR ARCH_X86_64)
   check_c_compiler_flag("-mpclmul" HAVE_PCLMUL)
 endif(ARCH_X86 OR ARCH_X86_64)
 
+
+
+if(ENABLE_LTO)
+  set(CFLAGS_LTO "-flto")
+  set(CFLAGS_NO_LTO "-fno-lto")
+
+  check_c_compiler_flag("-fwhole-program" HAVE_FLAG_WHOLE_PROGRAM)
+  if(HAVE_FLAG_WHOLE_PROGRAM)
+    set(LDFLAGS_LTO "-flto -fwhole-program")
+  else(HAVE_FLAG_WHOLE_PROGRAM)
+    set(LDFLAGS_LTO "-flto")
+  endif(HAVE_FLAG_WHOLE_PROGRAM)
+endif(ENABLE_LTO)
+
+
 check_c_source_compiles("
 #include <sys/types.h>
 #include <sys/socket.h>
diff --git a/cmake/config.cmake b/cmake/config.cmake
index e08955e..e77abc8 100644
--- a/cmake/config.cmake
+++ b/cmake/config.cmake
@@ -23,6 +23,8 @@ set(WITH_CAPABILITIES ${LINUX} CACHE BOOL "Include support for POSIX capabilitie
 set(ENABLE_LIBSODIUM TRUE CACHE BOOL "Use libsodium instead of NaCl")
 set(ENABLE_OPENSSL FALSE CACHE BOOL "Enable crypto implementations using OpenSSL")
 
+set(ENABLE_LTO FALSE CACHE BOOL "Enable link-time optimization")
+
 if(LINUX)
   set(ENABLE_SYSTEMD TRUE CACHE BOOL "Enable systemd support")
 endif(LINUX)
-- 
cgit v1.2.3