CMake/Modules/Compiler/Clang-C.cmake
Stephen Kelly d13758514c Project: Don't require computed default dialect if compiler was forced.
Commit 7235334a (Project: Determine default language dialect for the
compiler., 2015-09-15) introduced a mechanism to determine the default
dialect used for the running compiler.  If conditions in
the <CompilerId>-<Lang>.cmake file are such that compile features for
that version of the compiler should be supported, the _DEFAULT_STANDARD
is set to the computed value.

However, the CMakeForceCompiler module allows users to bypass execution of the
compiler by CMake.  In that case, do not set the _DEFAULT_STANDARD variable at
all, which effectively disables the compile-features where the module is used.

No compile features have ever been recorded where the module is used so no
functionality is lost.
2015-09-22 22:13:15 +02:00

45 lines
1.5 KiB
CMake

include(Compiler/Clang)
__compiler_clang(C)
cmake_policy(GET CMP0025 appleClangPolicy)
if(WIN32 OR (APPLE AND NOT appleClangPolicy STREQUAL NEW))
return()
endif()
if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 3.4)
set(CMAKE_C90_STANDARD_COMPILE_OPTION "-std=c90")
set(CMAKE_C90_EXTENSION_COMPILE_OPTION "-std=gnu90")
set(CMAKE_C99_STANDARD_COMPILE_OPTION "-std=c99")
set(CMAKE_C99_EXTENSION_COMPILE_OPTION "-std=gnu99")
set(CMAKE_C11_STANDARD_COMPILE_OPTION "-std=c11")
set(CMAKE_C11_EXTENSION_COMPILE_OPTION "-std=gnu11")
endif()
if(NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 3.4)
if (NOT CMAKE_C_COMPILER_FORCED)
if (NOT CMAKE_C_STANDARD_COMPUTED_DEFAULT)
message(FATAL_ERROR "CMAKE_C_STANDARD_COMPUTED_DEFAULT should be set for ${CMAKE_C_COMPILER_ID} (${CMAKE_C_COMPILER}) version ${CMAKE_C_COMPILER_VERSION}")
endif()
set(CMAKE_C_STANDARD_DEFAULT ${CMAKE_C_STANDARD_COMPUTED_DEFAULT})
endif()
endif()
macro(cmake_record_c_compile_features)
macro(_get_clang_features std_version list)
record_compiler_features(C "${std_version}" ${list})
endmacro()
set(_result 0)
if (UNIX AND NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 3.4)
_get_clang_features(${CMAKE_C11_STANDARD_COMPILE_OPTION} CMAKE_C11_COMPILE_FEATURES)
if (_result EQUAL 0)
_get_clang_features(${CMAKE_C99_STANDARD_COMPILE_OPTION} CMAKE_C99_COMPILE_FEATURES)
endif()
if (_result EQUAL 0)
_get_clang_features(${CMAKE_C90_STANDARD_COMPILE_OPTION} CMAKE_C90_COMPILE_FEATURES)
endif()
endif()
endmacro()