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Joerg Bornemann 7c3ca57b91 MSVC,Clang: Set CMAKE_CXX_COMPILER_PREDEFINES_COMMAND for the MSVC ABI
The variable was only set by the GNU-like compiler modules, so AUTOMOC
never generated a moc_predefs.h for compilers targeting the MSVC ABI
and moc parsed headers without the compiler's predefined macros.

MSVC dumps its predefined macros with '/PD', which needs the conforming
preprocessor. Require VS 2019 16.8, because 16.7 and older ignore the
flag with warning D9002 and emit no macros at all. clang-cl takes '-dM'
through '-Xclang'. Both also echo the preprocessed source, so feed them
an empty translation unit. clang with the GNU driver is excluded from
'Compiler/GNU' as well when it simulates MSVC, so give it the usual
'-dM -E' command there.

Fixes: #28093
2026-09-18 11:35:02 +02:00

45 lines
1.8 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.
# This module is shared by multiple languages; use include blocker.
if(__COMPILER_MSVC)
return()
endif()
set(__COMPILER_MSVC 1)
macro(__compiler_msvc lang)
set(CMAKE_${lang}_CLANG_TIDY_DRIVER_MODE "cl")
set(CMAKE_${lang}_INCLUDE_WHAT_YOU_USE_DRIVER_MODE "cl")
set(CMAKE_${lang}_COMPILE_OPTIONS_WARNING_AS_ERROR "-WX")
# /JMC "Just My Code" is only supported by MSVC 19.05 onward.
if (CMAKE_${lang}_COMPILER_VERSION VERSION_GREATER_EQUAL 19.05)
set(CMAKE_${lang}_COMPILE_OPTIONS_JMC "-JMC")
endif()
# The `/external:I` flag was made non-experimental in 19.29.30036.3.
if (CMAKE_${lang}_COMPILER_VERSION VERSION_GREATER_EQUAL 19.29.30036.3)
set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-external:I")
set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang}_WARNING "-external:W0 ")
endif ()
# '/PD' dumps the predefined macros, but it needs the conforming
# preprocessor and one of '/E', '/EP' or '/P'. VS 2019 16.7 and older
# ignore it with warning D9002, so require 16.8. '/EP' also echoes the
# preprocessed source, hence the empty translation unit.
if("${lang}" STREQUAL "CXX" AND
CMAKE_${lang}_COMPILER_VERSION VERSION_GREATER_EQUAL 19.28)
set(CMAKE_${lang}_COMPILER_PREDEFINES_COMMAND "${CMAKE_${lang}_COMPILER}")
if(CMAKE_${lang}_COMPILER_ARG1)
separate_arguments(_COMPILER_ARGS NATIVE_COMMAND "${CMAKE_${lang}_COMPILER_ARG1}")
list(APPEND CMAKE_${lang}_COMPILER_PREDEFINES_COMMAND ${_COMPILER_ARGS})
unset(_COMPILER_ARGS)
endif()
list(APPEND CMAKE_${lang}_COMPILER_PREDEFINES_COMMAND
"-nologo" "-w" "-Zc:preprocessor" "-PD" "-EP"
"${CMAKE_ROOT}/Modules/CMakeCXXCompilerPredefines.cpp")
endif()
set(CMAKE_${lang}_LINK_MODE LINKER)
endmacro()