CMake/CompileFlags.cmake
Robert Dailey a1dee224b8 CMake: Enable /MP for MSVC toolchain
A new cache option named `CMake_MSVC_PARALLEL` is now available that can
be used to control the usage of [`/MP`][1] to the MSVC compiler. This
enables parallelized builds on a per-translation unit basis. To enable
`/MP`, specify value `ON` to the option. Using an integral non-zero
value will control the specific number of threads used with the `/MP`
option, as opposed to letting the toolchain decide for you.

Fixes #17696

[1]: https://docs.microsoft.com/en-us/cpp/build/reference/mp-build-with-multiple-processes
2018-02-15 10:45:37 -06:00

108 lines
3.6 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#-----------------------------------------------------------------------------
# set some special flags for different compilers
#
if(WIN32 AND CMAKE_C_COMPILER_ID STREQUAL "Intel")
set(_INTEL_WINDOWS 1)
endif()
# Disable deprecation warnings for standard C functions.
# really only needed for newer versions of VS, but should
# not hurt other versions, and this will work into the
# future
if(MSVC OR _INTEL_WINDOWS)
add_definitions(-D_CRT_SECURE_NO_DEPRECATE -D_CRT_NONSTDC_NO_DEPRECATE)
else()
endif()
if(MSVC)
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -stack:10000000")
endif()
#silence duplicate symbol warnings on AIX
if(CMAKE_SYSTEM_NAME MATCHES "AIX")
if(NOT CMAKE_COMPILER_IS_GNUCXX)
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -bhalt:5 ")
endif()
endif()
if(CMAKE_SYSTEM_NAME MATCHES "IRIX")
if(NOT CMAKE_COMPILER_IS_GNUCXX)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wl,-woff84 -no_auto_include")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-woff15")
endif()
endif()
if(CMAKE_SYSTEM MATCHES "OSF1-V")
if(NOT CMAKE_COMPILER_IS_GNUCXX)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -timplicit_local -no_implicit_include ")
endif()
endif()
# Workaround for short jump tables on PA-RISC
if(CMAKE_SYSTEM_PROCESSOR MATCHES "^parisc")
if(CMAKE_COMPILER_IS_GNUCC)
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mlong-calls")
endif()
if(CMAKE_COMPILER_IS_GNUCXX)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mlong-calls")
endif()
endif()
if (CMAKE_CXX_COMPILER_ID STREQUAL SunPro AND
NOT DEFINED CMAKE_CXX${CMAKE_CXX_STANDARD}_STANDARD_COMPILE_OPTION)
if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.13)
if (NOT CMAKE_CXX_STANDARD OR CMAKE_CXX_STANDARD EQUAL 98)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++03")
elseif(CMAKE_VERSION VERSION_LESS 3.8.20170502)
# CMake knows how to add this flag for compilation as C++11,
# but has not been taught that SunPro needs it for linking too.
# Add it in a place that will be used for both.
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
endif()
else()
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -library=stlport4")
endif()
endif()
foreach(lang C CXX)
# Suppress warnings from PGI compiler.
if (CMAKE_${lang}_COMPILER_ID STREQUAL "PGI")
set(CMAKE_${lang}_FLAGS "${CMAKE_${lang}_FLAGS} -w")
endif()
endforeach()
# use the ansi CXX compile flag for building cmake
if (CMAKE_ANSI_CXXFLAGS)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_ANSI_CXXFLAGS}")
endif ()
if (CMAKE_ANSI_CFLAGS)
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${CMAKE_ANSI_CFLAGS}")
endif ()
# Allow per-translation-unit parallel builds when using MSVC
if(CMAKE_GENERATOR MATCHES "Visual Studio" AND
(CMAKE_C_COMPILER_ID MATCHES "MSVC|Intel" OR
CMAKE_CXX_COMPILER_ID MATCHES "MSVC|Intel"))
set(CMake_MSVC_PARALLEL ON CACHE STRING "\
Enables /MP flag for parallel builds using MSVC. Specify an \
integer value to control the number of threads used (Only \
works on some older versions of Visual Studio). Setting to \
ON lets the toolchain decide how many threads to use. Set to \
OFF to disable /MP completely." )
if(CMake_MSVC_PARALLEL)
if(CMake_MSVC_PARALLEL GREATER 0)
string(APPEND CMAKE_C_FLAGS " /MP${CMake_MSVC_PARALLEL}")
string(APPEND CMAKE_CXX_FLAGS " /MP${CMake_MSVC_PARALLEL}")
else()
string(APPEND CMAKE_C_FLAGS " /MP")
string(APPEND CMAKE_CXX_FLAGS " /MP")
endif()
endif()
endif()