]> git.ipfire.org Git - thirdparty/zstd.git/commitdiff
Refactored AddExtraCompilationFlags
authorMilan Ševčík <majlen@civ.zcu.cz>
Thu, 16 Mar 2017 15:24:33 +0000 (16:24 +0100)
committerMilan Ševčík <majlen@civ.zcu.cz>
Tue, 21 Mar 2017 09:43:08 +0000 (10:43 +0100)
 - Easier addition of new flags
 - Removed flags not used by default
 - Removed implicit PIC flag for all targets

build/cmake/CMakeModules/AddExtraCompilationFlags.cmake

index e480c7eadff72bdbcef3eac0e2fc9736fbf1c556..db5b48124e3f982c750103b9b2e0aab7e25ebc91 100644 (file)
+include(CheckCXXCompilerFlag)
+include(CheckCCompilerFlag)
+
+function(EnableCompilerFlag _flag _C _CXX)
+    message("Checking flag ${_flag}")
+    if (_C)
+        CHECK_C_COMPILER_FLAG(${_flag} C_FLAG)
+        if (C_FLAG)
+            set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${_flag}" CACHE INTERNAL "C Flags")
+        endif ()
+        unset(C_FLAG CACHE)
+    endif ()
+    if (_CXX)
+        CHECK_CXX_COMPILER_FLAG(${_flag} CXX_FLAG)
+        if (CXX_FLAG)
+            set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_flag}" CACHE INTERNAL "CXX Flags")
+        endif ()
+        unset(CXX_FLAG CACHE)
+    endif ()
+endfunction()
+
 MACRO(ADD_EXTRA_COMPILATION_FLAGS)
-    include(CheckCXXCompilerFlag)
-    include(CheckCCompilerFlag)
     if (CMAKE_COMPILER_IS_GNUCXX OR MINGW) #Not only UNIX but also WIN32 for MinGW
-
-        set(POSITION_INDEPENDENT_CODE_FLAG "-fPIC")
-        CHECK_C_COMPILER_FLAG(${POSITION_INDEPENDENT_CODE_FLAG} POSITION_INDEPENDENT_CODE_FLAG_ALLOWED)
-        if (POSITION_INDEPENDENT_CODE_FLAG_ALLOWED)
-            MESSAGE("Compiler flag ${POSITION_INDEPENDENT_CODE_FLAG} allowed")
-            set(ACTIVATE_POSITION_INDEPENDENT_CODE_FLAG "ON" CACHE BOOL "activate -fPIC flag")
-        else ()
-            MESSAGE("Compiler flag ${POSITION_INDEPENDENT_CODE_FLAG} not allowed")
-        endif (POSITION_INDEPENDENT_CODE_FLAG_ALLOWED)
-
-        set(WARNING_UNDEF "-Wundef")
-        CHECK_C_COMPILER_FLAG(${WARNING_UNDEF} WARNING_UNDEF_ALLOWED)
-        if (WARNING_UNDEF_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_UNDEF} allowed")
-            set(ACTIVATE_WARNING_UNDEF "ON" CACHE BOOL "activate -Wundef flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_UNDEF} not allowed")
-        endif (WARNING_UNDEF_ALLOWED)
-
-        set(WARNING_SHADOW "-Wshadow")
-        CHECK_C_COMPILER_FLAG(${WARNING_SHADOW} WARNING_SHADOW_ALLOWED)
-        if (WARNING_SHADOW_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_SHADOW} allowed")
-            set(ACTIVATE_WARNING_SHADOW "ON" CACHE BOOL "activate -Wshadow flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_SHADOW} not allowed")
-        endif (WARNING_SHADOW_ALLOWED)
-
-        set(WARNING_CAST_ALIGN "-Wcast-align")
-        CHECK_C_COMPILER_FLAG(${WARNING_CAST_ALIGN} WARNING_CAST_ALIGN_ALLOWED)
-        if (WARNING_CAST_ALIGN_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_CAST_ALIGN} allowed")
-            set(ACTIVATE_WARNING_CAST_ALIGN "ON" CACHE BOOL "activate -Wcast-align flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_CAST_ALIGN} not allowed")
-        endif (WARNING_CAST_ALIGN_ALLOWED)
-
-        set(WARNING_CAST_QUAL "-Wcast-qual")
-        CHECK_C_COMPILER_FLAG(${WARNING_CAST_QUAL} WARNING_CAST_QUAL_ALLOWED)
-        if (WARNING_CAST_QUAL_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_CAST_QUAL} allowed")
-            set(ACTIVATE_WARNING_CAST_QUAL "ON" CACHE BOOL "activate -Wcast-qual flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_CAST_QUAL} not allowed")
-        endif (WARNING_CAST_QUAL_ALLOWED)
-
-        set(WARNING_STRICT_PROTOTYPES "-Wstrict-prototypes")
-        CHECK_C_COMPILER_FLAG(${WARNING_STRICT_PROTOTYPES} WARNING_STRICT_PROTOTYPES_ALLOWED)
-        if (WARNING_STRICT_PROTOTYPES_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_STRICT_PROTOTYPES} allowed")
-            set(ACTIVATE_WARNING_STRICT_PROTOTYPES "ON" CACHE BOOL "activate -Wstrict-prototypes flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_STRICT_PROTOTYPES} not allowed")
-        endif (WARNING_STRICT_PROTOTYPES_ALLOWED)
-
-        set(WARNING_ALL "-Wall")
-        CHECK_C_COMPILER_FLAG(${WARNING_ALL} WARNING_ALL_ALLOWED)
-        if (WARNING_ALL_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_ALL} allowed")
-            set(ACTIVATE_WARNING_ALL "ON" CACHE BOOL "activate -Wall flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_ALL} not allowed")
-        endif (WARNING_ALL_ALLOWED)
-
-        set(WARNING_EXTRA "-Wextra")
-        CHECK_C_COMPILER_FLAG(${WARNING_EXTRA} WARNING_EXTRA_ALLOWED)
-        if (WARNING_EXTRA_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_EXTRA} allowed")
-            set(ACTIVATE_WARNING_EXTRA "ON" CACHE BOOL "activate -Wextra flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_EXTRA} not allowed")
-        endif (WARNING_EXTRA_ALLOWED)
-
-        set(WARNING_FLOAT_EQUAL "-Wfloat-equal")
-        CHECK_C_COMPILER_FLAG(${WARNING_FLOAT_EQUAL} WARNING_FLOAT_EQUAL_ALLOWED)
-        if (WARNING_FLOAT_EQUAL_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_FLOAT_EQUAL} allowed")
-            set(ACTIVATE_WARNING_FLOAT_EQUAL "OFF" CACHE BOOL "activate -Wfloat-equal flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_FLOAT_EQUAL} not allowed")
-        endif (WARNING_FLOAT_EQUAL_ALLOWED)
-
-        set(WARNING_SIGN_CONVERSION "-Wsign-conversion")
-        CHECK_C_COMPILER_FLAG(${WARNING_SIGN_CONVERSION} WARNING_SIGN_CONVERSION_ALLOWED)
-        if (WARNING_SIGN_CONVERSION_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_SIGN_CONVERSION} allowed")
-            set(ACTIVATE_WARNING_SIGN_CONVERSION "OFF" CACHE BOOL "activate -Wsign-conversion flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_SIGN_CONVERSION} not allowed")
-        endif (WARNING_SIGN_CONVERSION_ALLOWED)
-
-        if (ACTIVATE_POSITION_INDEPENDENT_CODE_FLAG)
-            list(APPEND CMAKE_C_FLAGS ${POSITION_INDEPENDENT_CODE_FLAG})
-        else ()
-            string(REPLACE ${POSITION_INDEPENDENT_CODE_FLAG} "" CMAKE_C_FLAGS "${POSITION_INDEPENDENT_CODE_FLAG}")
-        endif (ACTIVATE_POSITION_INDEPENDENT_CODE_FLAG)
-
-        if (ACTIVATE_WARNING_UNDEF)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_UNDEF})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_UNDEF})
-        else ()
-            string(REPLACE ${WARNING_UNDEF} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_UNDEF} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_UNDEF)
-
-        if (ACTIVATE_WARNING_SHADOW)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_SHADOW})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_SHADOW})
-        else ()
-            string(REPLACE ${WARNING_SHADOW} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_SHADOW} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_SHADOW)
-
-        if (ACTIVATE_WARNING_CAST_QUAL)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_CAST_QUAL})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_CAST_QUAL})
-        else ()
-            string(REPLACE ${WARNING_CAST_QUAL} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_CAST_QUAL} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_CAST_QUAL)
-
-        if (ACTIVATE_WARNING_CAST_ALIGN)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_CAST_ALIGN})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_CAST_ALIGN})
-        else ()
-            string(REPLACE ${WARNING_CAST_ALIGN} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_CAST_ALIGN} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_CAST_ALIGN)
-
-        if (ACTIVATE_WARNING_STRICT_PROTOTYPES)
-            list(APPEND CMAKE_C_FLAGS ${WARNING_STRICT_PROTOTYPES})
-        else ()
-            string(REPLACE ${WARNING_STRICT_PROTOTYPES} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_STRICT_PROTOTYPES)
-
-        if (ACTIVATE_WARNING_ALL)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_ALL})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_ALL})
-        else ()
-            string(REPLACE ${WARNING_ALL} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_ALL} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_ALL)
-
-        if (ACTIVATE_WARNING_EXTRA)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_EXTRA})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_EXTRA})
-        else ()
-            string(REPLACE ${WARNING_EXTRA} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_EXTRA} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_EXTRA)
-
-        if (ACTIVATE_WARNING_FLOAT_EQUAL)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_FLOAT_EQUAL})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_FLOAT_EQUAL})
-        else ()
-            string(REPLACE ${WARNING_FLOAT_EQUAL} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_FLOAT_EQUAL} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_FLOAT_EQUAL)
-
-        if (ACTIVATE_WARNING_SIGN_CONVERSION)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_SIGN_CONVERSION})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_SIGN_CONVERSION})
-        else ()
-            string(REPLACE ${WARNING_SIGN_CONVERSION} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_SIGN_CONVERSION} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_SIGN_CONVERSION)
-
         #Set c++11 by default
-        list(APPEND CMAKE_CXX_FLAGS "-std=c++11")
-
+        EnableCompilerFlag("-std=c++11" false true)
         #Set c99 by default
-        list(APPEND CMAKE_C_FLAGS "-std=c99")
-
-    elseif (MSVC)
-        # Add specific compilation flags for Windows Visual
+        EnableCompilerFlag("-std=c99" true false)
+        EnableCompilerFlag("-Wall" true true)
+        EnableCompilerFlag("-Wextra" true true)
+        EnableCompilerFlag("-Wundef" true true)
+        EnableCompilerFlag("-Wshadow" true true)
+        EnableCompilerFlag("-Wcast-align" true true)
+        EnableCompilerFlag("-Wcast-qual" true true)
+        EnableCompilerFlag("-Wstrict-prototypes" true false)
+    elseif (MSVC) # Add specific compilation flags for Windows Visual
+        EnableCompilerFlag("/Wall" true true)
 
-        set(WARNING_ALL "/Wall")
-        CHECK_C_COMPILER_FLAG(${WARNING_ALL} WARNING_ALL_ALLOWED)
-        if (WARNING_ALL_ALLOWED)
-            MESSAGE("Compiler flag ${WARNING_ALL} allowed")
-            set(ACTIVATE_WARNING_ALL "OFF" CACHE BOOL "activate /Wall flag")
-        else ()
-            MESSAGE("Compiler flag ${WARNING_ALL} not allowed")
-        endif (WARNING_ALL_ALLOWED)
-               
-        set(RTC_FLAG "/RTC1")
-        CHECK_C_COMPILER_FLAG(${RTC_FLAG} RTC_FLAG_ALLOWED)
-        if (RTC_FLAG_ALLOWED)
-            MESSAGE("Compiler flag ${RTC_FLAG} allowed")
-            set(ACTIVATE_RTC_FLAG "ON" CACHE BOOL "activate /RTC1 flag")
-        else ()
-            MESSAGE("Compiler flag ${RTC_FLAG} not allowed")
-        endif (RTC_FLAG_ALLOWED)
-               
-        set(ZC_FLAG "/Zc:forScope")
-        CHECK_C_COMPILER_FLAG(${ZC_FLAG} ZC_FLAG_ALLOWED)
-        if (ZC_FLAG_ALLOWED)
-            MESSAGE("Compiler flag ${ZC_FLAG} allowed")
-            set(ACTIVATE_ZC_FLAG "ON" CACHE BOOL "activate /Zc:forScope flag")
-        else ()
-            MESSAGE("Compiler flag ${ZC_FLAG} not allowed")
-        endif (ZC_FLAG_ALLOWED)
-               
-        set(GD_FLAG "/Gd")
-        CHECK_C_COMPILER_FLAG(${GD_FLAG} GD_FLAG_ALLOWED)
-        if (GD_FLAG_ALLOWED)
-            MESSAGE("Compiler flag ${GD_FLAG} allowed")
-            set(ACTIVATE_GD_FLAG "ON" CACHE BOOL "activate /Gd flag")
-        else ()
-            MESSAGE("Compiler flag ${GD_FLAG} not allowed")
-        endif (GD_FLAG_ALLOWED)
-               
-        set(ANALYZE_FLAG "/analyze:stacksize25000")
-        CHECK_C_COMPILER_FLAG(${ANALYZE_FLAG} ANALYZE_FLAG_ALLOWED)
-        if (ANALYZE_FLAG_ALLOWED)
-            MESSAGE("Compiler flag ${ANALYZE_FLAG} allowed")
-            set(ACTIVATE_ANALYZE_FLAG "ON" CACHE BOOL "activate /ANALYZE flag")
-        else ()
-            MESSAGE("Compiler flag ${ANALYZE_FLAG} not allowed")
-        endif (ANALYZE_FLAG_ALLOWED)
-
-        if (ACTIVATE_WARNING_ALL)
-            list(APPEND CMAKE_CXX_FLAGS ${WARNING_ALL})
-            list(APPEND CMAKE_C_FLAGS ${WARNING_ALL})
-        else ()
-            string(REPLACE ${WARNING_ALL} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${WARNING_ALL} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_WARNING_ALL)
-               
         # Only for DEBUG version
-        if (ACTIVATE_RTC_FLAG)
-            list(APPEND CMAKE_CXX_FLAGS_DEBUG ${RTC_FLAG})
-            list(APPEND CMAKE_C_FLAGS_DEBUG ${RTC_FLAG})
-        else ()
-            string(REPLACE ${RTC_FLAG} "" CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
-            string(REPLACE ${RTC_FLAG} "" CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG}")
-        endif (ACTIVATE_RTC_FLAG)
-               
-        if (ACTIVATE_ZC_FLAG)
-            list(APPEND CMAKE_CXX_FLAGS ${ZC_FLAG})
-            list(APPEND CMAKE_C_FLAGS ${ZC_FLAG})
-        else ()
-            string(REPLACE ${ZC_FLAG} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${ZC_FLAG} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_ZC_FLAG)
-               
-        if (ACTIVATE_GD_FLAG)
-            list(APPEND CMAKE_CXX_FLAGS ${GD_FLAG})
-            list(APPEND CMAKE_C_FLAGS ${GD_FLAG})
-        else ()
-            string(REPLACE ${GD_FLAG} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${GD_FLAG} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_GD_FLAG)
-               
-        if (ACTIVATE_ANALYZE_FLAG)
-            list(APPEND CMAKE_CXX_FLAGS ${ANALYZE_FLAG})
-            list(APPEND CMAKE_C_FLAGS ${ANALYZE_FLAG})
-        else ()
-            string(REPLACE ${ANALYZE_FLAG} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${ANALYZE_FLAG} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_ANALYZE_FLAG)
-               
+        EnableCompilerFlag("/RTC1" true true)
+        EnableCompilerFlag("/Zc:forScope" true true)
+        EnableCompilerFlag("/Gd" true true)
+        EnableCompilerFlag("/analyze:stacksize25000" true true)
+
         if (MSVC80 OR MSVC90 OR MSVC10 OR MSVC11)
             # To avoid compiler warning (level 4) C4571, compile with /EHa if you still want
             # your catch(...) blocks to catch structured exceptions.
-            list(APPEND CMAKE_CXX_FLAGS "/EHa")
+            EnableCompilerFlag("/EHa" false true)
         endif (MSVC80 OR MSVC90 OR MSVC10 OR MSVC11)
 
-        set(MULTITHREADED_COMPILATION "/MP")
-        MESSAGE("Compiler flag ${MULTITHREADED_COMPILATION} allowed")
-        set(ACTIVATE_MULTITHREADED_COMPILATION "ON" CACHE BOOL "activate /MP flag")
-
+        set(ACTIVATE_MULTITHREADED_COMPILATION "ON" CACHE BOOL "activate multi-threaded compilation (/MP flag)")
         if (ACTIVATE_MULTITHREADED_COMPILATION)
-            list(APPEND CMAKE_CXX_FLAGS ${MULTITHREADED_COMPILATION})
-            list(APPEND CMAKE_C_FLAGS ${MULTITHREADED_COMPILATION})
-        else ()
-            string(REPLACE ${MULTITHREADED_COMPILATION} "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
-            string(REPLACE ${MULTITHREADED_COMPILATION} "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
-        endif (ACTIVATE_MULTITHREADED_COMPILATION)
+            EnableCompilerFlag("/MP" true true)
+        endif ()
 
         #For exceptions
-        list(APPEND CMAKE_CXX_FLAGS "/EHsc")
-        list(APPEND CMAKE_C_FLAGS "/EHsc")
+        EnableCompilerFlag("/EHsc" true true)
         
         # UNICODE SUPPORT
-        list(APPEND CMAKE_CXX_FLAGS "/D_UNICODE /DUNICODE")
-        list(APPEND CMAKE_C_FLAGS "/D_UNICODE /DUNICODE")
+        EnableCompilerFlag("/D_UNICODE" true true)
+        EnableCompilerFlag("/DUNICODE" true true)
     endif ()
 
     # Remove duplicates compilation flags
-       FOREACH (flag_var CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
-                CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
-                       CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
-                               CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
-           separate_arguments(${flag_var})
-           list(REMOVE_DUPLICATES ${flag_var})
-           string(REPLACE ";" " " ${flag_var} "${${flag_var}}")
-           set(${flag_var} "${${flag_var}}" CACHE STRING "common build flags" FORCE)
+    FOREACH (flag_var CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
+             CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
+             CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+             CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+        separate_arguments(${flag_var})
+        list(REMOVE_DUPLICATES ${flag_var})
+        string(REPLACE ";" " " ${flag_var} "${${flag_var}}")
+        set(${flag_var} "${${flag_var}}" CACHE STRING "common build flags" FORCE)
     ENDFOREACH (flag_var)  
 
     if (MSVC)
         # Replace /MT to /MD flag
-       # Replace /O2 to /O3 flag
+        # Replace /O2 to /O3 flag
         FOREACH (flag_var CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
-                CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
-                       CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
-                               CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+                 CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO
+                 CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+                 CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
             STRING(REGEX REPLACE "/MT" "/MD" ${flag_var} "${${flag_var}}")
-               STRING(REGEX REPLACE "/O2" "/Ox" ${flag_var} "${${flag_var}}")
+            STRING(REGEX REPLACE "/O2" "/Ox" ${flag_var} "${${flag_var}}")
         ENDFOREACH (flag_var)      
     endif ()