Add LTO and strip to pybind11_add_module

CMakeLists.txt

@@ -59,14 +59,14 @@ function(pybind11_add_module target_name)
   # missing symbols, but that's perfectly fine -- they will be resolved at
   # import time.
   if(MSVC)
-    target_link_libraries(${target_name} ${PYTHON_LIBRARIES})
+    target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES})
   elseif(APPLE)
     # Make sure OS X does not have any issues with missing symbols
     target_link_libraries(${target_name} PRIVATE "-undefined dynamic_lookup")
   endif()
 
-  # Make sure C++11/14 are enabled
   if(NOT MSVC)
+    # Make sure C++11/14 are enabled
     check_cxx_compiler_flag("-std=c++14" HAS_CPP14_FLAG)
     check_cxx_compiler_flag("-std=c++11" HAS_CPP11_FLAG)
 
@@ -78,12 +78,59 @@ function(pybind11_add_module target_name)
       message(FATAL_ERROR "Unsupported compiler -- pybind11 requires C++11 support!")
     endif()
 
+    # Enable link time optimization and set the default symbol
+    # visibility to hidden (very important to obtain small binaries)
     string(TOUPPER "${CMAKE_BUILD_TYPE}" U_CMAKE_BUILD_TYPE)
     if (NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
+      # Check for Link Time Optimization support (GCC/Clang)
+      check_cxx_compiler_flag("-flto" HAS_LTO_FLAG)
+      if(HAS_LTO_FLAG)
+        target_compile_options(${target_name} PRIVATE -flto)
+      endif()
+
+      # Intel equivalent to LTO is called IPO
+      if(CMAKE_CXX_COMPILER_ID MATCHES "Intel")
+        check_cxx_compiler_flag("-ipo" HAS_IPO_FLAG)
+        if(HAS_IPO_FLAG)
+          target_compile_options(${target_name} PRIVATE -ipo)
+        endif()
+      endif()
+
       # Default symbol visibility
       target_compile_options(${target_name} PRIVATE "-fvisibility=hidden")
+
+      # Strip unnecessary sections of the binary on Linux/Mac OS
+      if(CMAKE_STRIP)
+        if(APPLE)
+          add_custom_command(TARGET ${target_name} POST_BUILD
+                             COMMAND ${CMAKE_STRIP} -u -r $<TARGET_FILE:${target_name}>)
+        else()
+          add_custom_command(TARGET ${target_name} POST_BUILD
+                             COMMAND ${CMAKE_STRIP} $<TARGET_FILE:${target_name}>)
         endif()
       endif()
+    endif()
+  elseif(MSVC)
+    # /MP enables multithreaded builds (relevant when there are many files), /bigobj is
+    # needed for bigger binding projects due to the limit to 64k addressable sections
+    target_compile_options(${target_name} PRIVATE /MP /bigobj)
+
+    # Enforce link time code generation on MSVC, except in debug mode
+    target_compile_options(${target_name} PRIVATE $<$<NOT:$<CONFIG:Debug>>:/GL>)
+    # Fancy generator expressions don't work with linker flags, for reasons unknown
+    set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS_RELEASE /LTCG)
+    set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS_MINSIZEREL /LTCG)
+    set_property(TARGET ${target_name} APPEND_STRING PROPERTY LINK_FLAGS_RELWITHDEBINFO /LTCG)
+  endif()
+endfunction()
+
+# Compile with compiler warnings turned on
+function(pybind11_turn_on_warnings target_name)
+  if(MSVC)
+    target_compile_options(${target_name} PRIVATE /W4)
+  else()
+    target_compile_options(${target_name} PRIVATE -Wall -Wextra)
+  endif()
 endfunction()
 
 if (PYBIND11_TEST)

example/CMakeLists.txt

@@ -1,5 +1,3 @@
-include(CheckCXXCompilerFlag)
-
 # Set a default build configuration if none is specified. 'MinSizeRel' produces the smallest binaries
 if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   message(STATUS "Setting build type to 'MinSizeRel' as none was specified.")
@@ -7,39 +5,6 @@ if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release"
     "MinSizeRel" "RelWithDebInfo")
 endif()
-string(TOUPPER "${CMAKE_BUILD_TYPE}" U_CMAKE_BUILD_TYPE)
-
-if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Intel")
-  # Enable link time optimization and set the default symbol
-  # visibility to hidden (very important to obtain small binaries)
-  if(NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
-    # Check for Link Time Optimization support
-    # (GCC/Clang)
-    CHECK_CXX_COMPILER_FLAG("-flto" HAS_LTO_FLAG)
-    if(HAS_LTO_FLAG)
-      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -flto")
-    endif()
-
-    # Intel equivalent to LTO is called IPO
-    if(CMAKE_CXX_COMPILER_ID MATCHES "Intel")
-      CHECK_CXX_COMPILER_FLAG("-ipo" HAS_IPO_FLAG)
-      if(HAS_IPO_FLAG)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ipo")
-      endif()
-    endif()
-  endif()
-endif()
-
-# Compile with compiler warnings turned on
-if(MSVC)
-  if(CMAKE_CXX_FLAGS MATCHES "/W[0-4]")
-    string(REGEX REPLACE "/W[0-4]" "/W4" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-  else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
-  endif()
-elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
-endif()
 
 set(PYBIND11_EXAMPLES
   example1.cpp
@@ -74,6 +39,8 @@ endif()
 
 # Create the binding library
 pybind11_add_module(example example.cpp ${PYBIND11_EXAMPLES})
+pybind11_turn_on_warnings(example)
+
 if(EIGEN3_FOUND)
   target_include_directories(example PRIVATE ${EIGEN3_INCLUDE_DIR})
   target_compile_definitions(example PRIVATE -DPYBIND11_TEST_EIGEN)
@@ -90,40 +57,6 @@ foreach(CompilerFlag ${CompilerFlags})
   set_target_properties(example PROPERTIES ${CompilerFlag} ${PROJECT_SOURCE_DIR}/example)
 endforeach()
 
-if(WIN32)
-  if(MSVC)
-    # /MP enables multithreaded builds (relevant when there are many files), /bigobj is
-    # needed for bigger binding projects due to the limit to 64k addressable sections
-    set_property(TARGET example APPEND PROPERTY COMPILE_OPTIONS /MP /bigobj)
-    # Enforce size-based optimization and link time code generation on MSVC
-    # (~30% smaller binaries in experiments); do nothing in debug mode.
-    set_property(TARGET example APPEND PROPERTY COMPILE_OPTIONS
-      "$<$<CONFIG:Release>:/Os>" "$<$<CONFIG:Release>:/GL>"
-      "$<$<CONFIG:MinSizeRel>:/Os>" "$<$<CONFIG:MinSizeRel>:/GL>"
-      "$<$<CONFIG:RelWithDebInfo>:/Os>" "$<$<CONFIG:RelWithDebInfo>:/GL>"
-    )
-    set_property(TARGET example APPEND_STRING PROPERTY LINK_FLAGS_RELEASE "/LTCG ")
-    set_property(TARGET example APPEND_STRING PROPERTY LINK_FLAGS_MINSIZEREL "/LTCG ")
-    set_property(TARGET example APPEND_STRING PROPERTY LINK_FLAGS_RELWITHDEBINFO "/LTCG ")
-  endif()
-elseif(UNIX)
-  # Optimize for a small binary size
-  if(NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
-    set_target_properties(example PROPERTIES COMPILE_FLAGS "-Os")
-  endif()
-
-  # Strip unnecessary sections of the binary on Linux/Mac OS
-  if(APPLE)
-    if(NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
-      add_custom_command(TARGET example POST_BUILD COMMAND strip -u -r $<TARGET_FILE:example>)
-    endif()
-  else()
-    if(NOT ${U_CMAKE_BUILD_TYPE} MATCHES DEBUG)
-      add_custom_command(TARGET example POST_BUILD COMMAND strip $<TARGET_FILE:example>)
-    endif()
-  endif()
-endif()
-
 set(RUN_TEST ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/run_test.py)
 if(MSVC OR CMAKE_CXX_COMPILER_ID MATCHES "Intel")
   set(RUN_TEST ${RUN_TEST} --relaxed)