cmake: Improve checks for compiler flags

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

1 files changed, 108 insertions, 0 deletions

diff --git a/CompilerChecks.cmake b/CompilerChecks.cmake
new file mode 100644
index 0000000..f5a3c7f
--- /dev/null
+++ b/CompilerChecks.cmake
@@ -0,0 +1,108 @@
+include(AddCCompilerFlag)
+include(CheckCCompilerFlagSSP)
+
+if (UNIX)
+    #
+    # Check for -Werror turned on if possible
+    #
+    # This will prevent that compiler flags are detected incorrectly.
+    #
+    check_c_compiler_flag("-Werror" REQUIRED_FLAGS_WERROR)
+    if (REQUIRED_FLAGS_WERROR)
+        set(CMAKE_REQUIRED_FLAGS "-Werror")
+
+        if (PICKY_DEVELOPER)
+            list(APPEND SUPPORTED_COMPILER_FLAGS "-Werror")
+        endif()
+    endif()
+
+    add_c_compiler_flag("-std=gnu99" SUPPORTED_COMPILER_FLAGS)
+    #add_c_compiler_flag("-Wpedantic" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wall" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wshadow" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wmissing-prototypes" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wcast-align" SUPPORTED_COMPILER_FLAGS)
+    #add_c_compiler_flag("-Wcast-qual" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=address" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wstrict-prototypes" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=strict-prototypes" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wwrite-strings" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=write-strings" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror-implicit-function-declaration" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wpointer-arith" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=pointer-arith" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wdeclaration-after-statement" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=declaration-after-statement" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wreturn-type" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=return-type" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wuninitialized" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=uninitialized" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wimplicit-fallthrough" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=strict-overflow" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wstrict-overflow=2" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Wno-format-zero-length" SUPPORTED_COMPILER_FLAGS)
+
+    check_c_compiler_flag("-Wformat" REQUIRED_FLAGS_WFORMAT)
+    if (REQUIRED_FLAGS_WFORMAT)
+        list(APPEND SUPPORTED_COMPILER_FLAGS "-Wformat")
+        set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Wformat")
+    endif()
+    add_c_compiler_flag("-Wformat-security" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("-Werror=format-security" SUPPORTED_COMPILER_FLAGS)
+
+    # Allow zero for a variadic macro argument
+    string(TOLOWER "${CMAKE_C_COMPILER_ID}" _C_COMPILER_ID)
+    if ("${_C_COMPILER_ID}" STREQUAL "clang")
+        add_c_compiler_flag("-Wno-gnu-zero-variadic-macro-arguments" SUPPORTED_COMPILER_FLAGS)
+    endif()
+
+    add_c_compiler_flag("-fno-common" SUPPORTED_COMPILER_FLAGS)
+
+    if (CMAKE_BUILD_TYPE)
+        string(TOLOWER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE_LOWER)
+        if (CMAKE_BUILD_TYPE_LOWER MATCHES (release|relwithdebinfo|minsizerel))
+            add_c_compiler_flag("-Wp,-D_FORTIFY_SOURCE=2" SUPPORTED_COMPILER_FLAGS)
+        endif()
+    endif()
+
+    check_c_compiler_flag_ssp("-fstack-protector-strong" WITH_STACK_PROTECTOR_STRONG)
+    if (WITH_STACK_PROTECTOR_STRONG)
+        list(APPEND SUPPORTED_COMPILER_FLAGS "-fstack-protector-strong")
+        # This is needed as Solaris has a seperate libssp
+        if (SOLARIS)
+            list(APPEND SUPPORTED_LINKER_FLAGS "-fstack-protector-strong")
+        endif()
+    else (WITH_STACK_PROTECTOR_STRONG)
+        check_c_compiler_flag_ssp("-fstack-protector" WITH_STACK_PROTECTOR)
+        if (WITH_STACK_PROTECTOR)
+            list(APPEND SUPPORTED_COMPILER_FLAGS "-fstack-protector")
+            # This is needed as Solaris has a seperate libssp
+            if (SOLARIS)
+                list(APPEND SUPPORTED_LINKER_FLAGS "-fstack-protector")
+            endif()
+        endif()
+    endif (WITH_STACK_PROTECTOR_STRONG)
+
+    check_c_compiler_flag_ssp("-fstack-clash-protection" WITH_STACK_CLASH_PROTECTION)
+    if (WITH_STACK_CLASH_PROTECTION)
+        list(APPEND SUPPORTED_COMPILER_FLAGS "-fstack-clash-protection")
+    endif()
+
+    if (PICKY_DEVELOPER)
+        add_c_compiler_flag("-Wno-error=deprecated-declarations" SUPPORTED_COMPILER_FLAGS)
+        add_c_compiler_flag("-Wno-error=tautological-compare" SUPPORTED_COMPILER_FLAGS)
+    endif()
+
+    # Unset CMAKE_REQUIRED_FLAGS
+    unset(CMAKE_REQUIRED_FLAGS)
+endif()
+
+if (MSVC)
+    add_c_compiler_flag("/D _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES=1" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("/D _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES_COUNT=1" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("/D _CRT_NONSTDC_NO_WARNINGS=1" SUPPORTED_COMPILER_FLAGS)
+    add_c_compiler_flag("/D _CRT_SECURE_NO_WARNINGS=1" SUPPORTED_COMPILER_FLAGS)
+endif()
+
+set(DEFAULT_C_COMPILE_FLAGS ${SUPPORTED_COMPILER_FLAGS} CACHE INTERNAL "Default C Compiler Flags" FORCE)
+set(DEFAULT_LINK_FLAGS ${SUPPORTED_LINKER_FLAGS} CACHE INTERNAL "Default C Linker Flags" FORCE)