# Copyright (C) Viktor Szakats # SPDX-License-Identifier: BSD-3-Clause include(CheckCCompilerFlag) set(_picky "") set(_picky_nocheck "") # not to pass to feature checks option(ENABLE_WERROR "Turn compiler warnings into errors" OFF) option(PICKY_COMPILER "Enable picky compiler options" ON) if(ENABLE_WERROR) if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.24) set(CMAKE_COMPILE_WARNING_AS_ERROR ON) else() if(MSVC) list(APPEND _picky_nocheck "-WX") else() # llvm/clang and gcc style options list(APPEND _picky_nocheck "-Werror") endif() endif() if((CMAKE_C_COMPILER_ID STREQUAL "GNU" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 5.0) OR CMAKE_C_COMPILER_ID MATCHES "Clang") list(APPEND _picky_nocheck "-pedantic-errors") endif() endif() if(MSVC) list(APPEND _picky "-W4") # Use the highest warning level for Visual Studio. endif() if(PICKY_COMPILER) if(CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID MATCHES "Clang") # https://clang.llvm.org/docs/DiagnosticsReference.html # https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html # _picky_enable = Options we want to enable as-is. # _picky_detect = Options we want to test first and enable if available. # Prefer the -Wextra alias with clang. if(CMAKE_C_COMPILER_ID MATCHES "Clang") set(_picky_enable "-Wextra") else() set(_picky_enable "-W") endif() list(APPEND _picky_enable -Wall -pedantic ) # ---------------------------------- # Add new options here, if in doubt: # ---------------------------------- set(_picky_detect ) # Assume these options always exist with both clang and gcc. # Require clang 3.0 / gcc 2.95 or later. list(APPEND _picky_enable -Wbad-function-cast # clang 2.7 gcc 2.95 -Wconversion # clang 2.7 gcc 2.95 -Winline # clang 1.0 gcc 1.0 -Wmissing-declarations # clang 1.0 gcc 2.7 -Wmissing-prototypes # clang 1.0 gcc 1.0 -Wnested-externs # clang 1.0 gcc 2.7 -Wno-long-long # clang 1.0 gcc 2.95 -Wno-multichar # clang 1.0 gcc 2.95 -Wpointer-arith # clang 1.0 gcc 1.4 -Wshadow # clang 1.0 gcc 2.95 -Wsign-compare # clang 1.0 gcc 2.95 -Wundef # clang 1.0 gcc 2.95 -Wunused # clang 1.1 gcc 2.95 -Wwrite-strings # clang 1.0 gcc 1.4 ) # Always enable with clang, version dependent with gcc set(_picky_common_old -Waddress # clang 2.7 gcc 4.3 -Wattributes # clang 2.7 gcc 4.1 -Wcast-align # clang 1.0 gcc 4.2 -Wcast-qual # clang 3.0 gcc 3.4.6 -Wdeclaration-after-statement # clang 1.0 gcc 3.4 -Wdiv-by-zero # clang 2.7 gcc 4.1 -Wempty-body # clang 2.7 gcc 4.3 -Wendif-labels # clang 1.0 gcc 3.3 -Wfloat-equal # clang 1.0 gcc 2.96 (3.0) -Wformat-security # clang 2.7 gcc 4.1 -Wignored-qualifiers # clang 2.8 gcc 4.3 -Wmissing-field-initializers # clang 2.7 gcc 4.1 -Wmissing-noreturn # clang 2.7 gcc 4.1 -Wno-format-nonliteral # clang 1.0 gcc 2.96 (3.0) -Wno-system-headers # clang 1.0 gcc 3.0 # -Wpadded # clang 2.9 gcc 4.1 # Not used: We cannot change public structs -Wold-style-definition # clang 2.7 gcc 3.4 -Wredundant-decls # clang 2.7 gcc 4.1 -Wsign-conversion # clang 2.9 gcc 4.3 -Wno-error=sign-conversion # FIXME -Wstrict-prototypes # clang 1.0 gcc 3.3 # -Wswitch-enum # clang 2.7 gcc 4.1 # Not used: It basically disallows default case -Wtype-limits # clang 2.7 gcc 4.3 -Wunreachable-code # clang 2.7 gcc 4.1 -Wunused-macros # clang 2.7 gcc 4.1 -Wunused-parameter # clang 2.7 gcc 4.1 -Wvla # clang 2.8 gcc 4.3 ) if(CMAKE_C_COMPILER_ID MATCHES "Clang") list(APPEND _picky_enable ${_picky_common_old} -Wshift-sign-overflow # clang 2.9 -Wshorten-64-to-32 # clang 1.0 -Wformat=2 # clang 3.0 gcc 4.8 ) if(NOT MSVC) list(APPEND _picky_enable -Wlanguage-extension-token # clang 3.0 ) endif() # Enable based on compiler version if((CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 3.6) OR (CMAKE_C_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 6.3)) list(APPEND _picky_enable -Wdouble-promotion # clang 3.6 gcc 4.6 appleclang 6.3 -Wenum-conversion # clang 3.2 gcc 10.0 appleclang 4.6 g++ 11.0 -Wheader-guard # clang 3.4 appleclang 5.1 -Wpragmas # clang 3.5 gcc 4.1 appleclang 6.0 -Wsometimes-uninitialized # clang 3.2 appleclang 4.6 # -Wunreachable-code-break # clang 3.5 appleclang 6.0 # Not used: Silent in "unity" builds -Wunused-const-variable # clang 3.4 gcc 6.0 appleclang 5.1 ) endif() if((CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 3.9) OR (CMAKE_C_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 8.3)) list(APPEND _picky_enable -Wcomma # clang 3.9 appleclang 8.3 -Wmissing-variable-declarations # clang 3.2 appleclang 4.6 ) endif() if((CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 7.0) OR (CMAKE_C_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 10.3)) list(APPEND _picky_enable -Wassign-enum # clang 7.0 appleclang 10.3 -Wextra-semi-stmt # clang 7.0 appleclang 10.3 ) endif() if((CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 10.0) OR (CMAKE_C_COMPILER_ID STREQUAL "AppleClang" AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 12.4)) list(APPEND _picky_enable -Wimplicit-fallthrough # clang 4.0 gcc 7.0 appleclang 12.4 # We do silencing for clang 10.0 and above only -Wxor-used-as-pow # clang 10.0 gcc 13.0 ) endif() else() # gcc # Enable based on compiler version if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.3) list(APPEND _picky_enable ${_picky_common_old} -Wclobbered # gcc 4.3 -Wmissing-parameter-type # gcc 4.3 -Wold-style-declaration # gcc 4.3 -Wpragmas # clang 3.5 gcc 4.1 appleclang 6.0 -Wstrict-aliasing=3 # gcc 4.0 -ftree-vrp # gcc 4.3 (required for -Warray-bounds, included in -Wall) ) endif() if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.5) list(APPEND _picky_enable -Wjump-misses-init # gcc 4.5 ) if(MINGW) list(APPEND _picky_enable -Wno-pedantic-ms-format # gcc 4.5 (MinGW-only) ) endif() endif() if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.8) list(APPEND _picky_enable -Wdouble-promotion # clang 3.6 gcc 4.6 appleclang 6.3 -Wformat=2 # clang 3.0 gcc 4.8 -Wtrampolines # gcc 4.6 ) endif() if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 5.0) list(APPEND _picky_enable -Warray-bounds=2 # clang 3.0 gcc 5.0 (clang default: -Warray-bounds) ) endif() if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 6.0) list(APPEND _picky_enable -Wduplicated-cond # gcc 6.0 -Wnull-dereference # clang 3.0 gcc 6.0 (clang default) -fdelete-null-pointer-checks -Wshift-negative-value # clang 3.7 gcc 6.0 (clang default) -Wshift-overflow=2 # clang 3.0 gcc 6.0 (clang default: -Wshift-overflow) -Wunused-const-variable # clang 3.4 gcc 6.0 appleclang 5.1 ) endif() if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 7.0) list(APPEND _picky_enable -Walloc-zero # gcc 7.0 -Wduplicated-branches # gcc 7.0 -Wformat-overflow=2 # gcc 7.0 -Wformat-truncation=2 # gcc 7.0 -Wimplicit-fallthrough # clang 4.0 gcc 7.0 -Wrestrict # gcc 7.0 ) endif() if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 10.0) list(APPEND _picky_enable -Warith-conversion # gcc 10.0 -Wenum-conversion # clang 3.2 gcc 10.0 appleclang 4.6 g++ 11.0 ) endif() if(CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 13.0) list(APPEND _picky_enable -Warray-compare # clang 20.0 gcc 12.0 -Wenum-int-mismatch # gcc 13.0 -Wxor-used-as-pow # clang 10.0 gcc 13.0 ) endif() endif() # set(_picky_skipped "") foreach(_ccopt IN LISTS _picky_enable) string(REGEX MATCH "-W([a-z0-9-]+)" _ccmatch "${_ccopt}") if(_ccmatch AND CMAKE_C_FLAGS MATCHES "-Wno-${CMAKE_MATCH_1}" AND NOT _ccopt STREQUAL "-Wall" AND NOT _ccopt MATCHES "^-Wno-") string(APPEND _picky_skipped " ${_ccopt}") else() list(APPEND _picky "${_ccopt}") endif() endforeach() if(_picky_skipped) message(STATUS "Picky compiler options skipped due to CMAKE_C_FLAGS override:${_picky_skipped}") endif() foreach(_ccopt IN LISTS _picky_detect) # Use a unique variable name 1. for meaningful log output 2. to have a fresh, undefined variable for each detection string(MAKE_C_IDENTIFIER "OPT${_ccopt}" _optvarname) # GCC only warns about unknown -Wno- options if there are also other diagnostic messages, # so test for the positive form instead string(REPLACE "-Wno-" "-W" _ccopt_on "${_ccopt}") check_c_compiler_flag(${_ccopt_on} ${_optvarname}) if(${_optvarname}) list(APPEND _picky "${_ccopt}") endif() endforeach() elseif(MSVC AND MSVC_VERSION LESS_EQUAL 1943) # Skip for untested/unreleased newer versions list(APPEND _picky "-Wall") list(APPEND _picky "-wd4061") # enumerator 'A' in switch of enum 'B' is not explicitly handled by a case label list(APPEND _picky "-wd4191") # 'type cast': unsafe conversion from 'FARPROC' to 'void (__cdecl *)(void)' list(APPEND _picky "-wd4255") # no function prototype given: converting '()' to '(void)' (in winuser.h) list(APPEND _picky "-wd4464") # relative include path contains '..' list(APPEND _picky "-wd4548") # expression before comma has no effect; expected expression with side-effect (in FD_SET()) list(APPEND _picky "-wd4574") # 'M' is defined to be '0': did you mean to use '#if M'? (in ws2tcpip.h) list(APPEND _picky "-wd4668") # 'M' is not defined as a preprocessor macro, replacing with '0' for '#if/#elif' (in winbase.h) list(APPEND _picky "-wd4710") # 'snprintf': function not inlined list(APPEND _picky "-wd4711") # function 'A' selected for automatic inline expansion # volatile access of '' is subject to /volatile: setting; # consider using __iso_volatile_load/store intrinsic functions (ARM64) list(APPEND _picky "-wd4746") list(APPEND _picky "-wd4774") # 'snprintf': format string expected in argument 3 is not a string literal list(APPEND _picky "-wd4820") # 'A': 'N' bytes padding added after data member 'B' if(MSVC_VERSION GREATER_EQUAL 1900) list(APPEND _picky "-wd5045") # Compiler will insert Spectre mitigation for memory load if /Qspectre switch specified endif() endif() endif() # clang-cl if(CMAKE_C_COMPILER_ID STREQUAL "Clang" AND MSVC) list(APPEND _picky "-Wno-language-extension-token") # Allow __int64 foreach(_wlist IN ITEMS _picky_nocheck _picky) set(_picky_tmp "") foreach(_ccopt IN LISTS "${_wlist}") # Prefix -Wall, otherwise clang-cl interprets it as an MSVC option and translates it to -Weverything if(_ccopt MATCHES "^-W" AND NOT _ccopt STREQUAL "-Wall") list(APPEND _picky_tmp ${_ccopt}) else() list(APPEND _picky_tmp "-clang:${_ccopt}") endif() endforeach() set("${_wlist}" ${_picky_tmp}) # cmake-lint: disable=C0103 endforeach() endif() if(_picky_nocheck OR _picky) set(_picky_tmp "${_picky_nocheck}" "${_picky}") string(REPLACE ";" " " _picky_tmp "${_picky_tmp}") string(STRIP "${_picky_tmp}" _picky_tmp) message(STATUS "Picky compiler options: ${_picky_tmp}") set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS "${_picky_nocheck}" "${_picky}") # Apply to all feature checks string(REPLACE ";" " " _picky_tmp "${_picky}") string(APPEND CMAKE_REQUIRED_FLAGS " ${_picky_tmp}") unset(_picky) unset(_picky_tmp) endif()