CMake: Correctly identify CPU architecture, hopefully

because, sadly, CMAKE_SYSTEM_PROCESSOR is almost useless and they don't
have a more useful alternative either :-/
This commit is contained in:
Daniel Gibson 2022-02-27 00:43:07 +01:00
parent ed918cf423
commit 35232218e9

View file

@ -76,13 +76,82 @@ set(REF_SRC_DIR ${SOURCE_DIR}/client/refresh)
set(YQ2OSTYPE "${CMAKE_SYSTEM_NAME}" CACHE STRING "Override operation system type") set(YQ2OSTYPE "${CMAKE_SYSTEM_NAME}" CACHE STRING "Override operation system type")
add_definitions(-DYQ2OSTYPE="${YQ2OSTYPE}") add_definitions(-DYQ2OSTYPE="${YQ2OSTYPE}")
# Architecture string. # Architecture string
set(YQ2ARCH "${CMAKE_SYSTEM_PROCESSOR}" CACHE STRING "Override CPU architecture") # work around CMake's useless/broken CMAKE_SYSTEM_PROCESSOR (taken from dhewm3)
string(REGEX REPLACE "amd64" "x86_64" ARCH "${YQ2ARCH}")
string(REGEX REPLACE "i.86" "i386" ARCH "${ARCH}") set(cpu ${CMAKE_SYSTEM_PROCESSOR})
string(REGEX REPLACE "^arm.*" "arm" ARCH "${ARCH}")
# Originally, ${CMAKE_SYSTEM_PROCESSOR} was supposed to contain the *target* CPU, according to CMake's documentation.
# As far as I can tell this has always been broken (always returns host CPU) at least on Windows
# (see e.g. https://cmake.org/pipermail/cmake-developers/2014-September/011405.html) and wasn't reliable on
# other systems either, for example on Linux with 32bit userland but 64bit kernel it returned the kernel CPU type
# (e.g. x86_64 instead of i686). Instead of fixing this, CMake eventually updated their documentation in 3.20,
# now it's officially the same as CMAKE_HOST_SYSTEM_PROCESSOR except when cross-compiling (where it's explicitly set)
# So we gotta figure out the actual target CPU type ourselves..
if(NOT (CMAKE_SYSTEM_PROCESSOR STREQUAL CMAKE_HOST_SYSTEM_PROCESSOR))
# special case: cross-compiling, here CMAKE_SYSTEM_PROCESSOR should be correct, hopefully
# (just leave cpu at ${CMAKE_SYSTEM_PROCESSOR})
elseif(MSVC)
message(DEBUG "CMAKE_GENERATOR_PLATFORM: ${CMAKE_GENERATOR_PLATFORM}")
if(CMAKE_GENERATOR_PLATFORM STREQUAL "Win32")
set(cpu "i386")
elseif(CMAKE_GENERATOR_PLATFORM STREQUAL "x64")
set(cpu "x86_64")
elseif(CMAKE_GENERATOR_PLATFORM STREQUAL "ARM")
# at least on RPi 32bit, gcc -dumpmachine outputs "arm-linux-gnueabihf",
# so we'll use "arm" there => use the same for 32bit ARM on MSVC
set(cpu "arm")
elseif(CMAKE_GENERATOR_PLATFORM STREQUAL "ARM64")
set(cpu "arm64")
else()
message(FATAL_ERROR "Unknown Target CPU/platform ${CMAKE_GENERATOR_PLATFORM}")
endif()
message(DEBUG " => CPU architecture extracted from that: \"${cpu}\"")
else() # not MSVC and not cross-compiling, assume GCC or clang (-compatible), seems to work for MinGW as well
execute_process(COMMAND ${CMAKE_C_COMPILER} "-dumpmachine"
RESULT_VARIABLE cc_dumpmachine_res
OUTPUT_VARIABLE cc_dumpmachine_out)
if(cc_dumpmachine_res EQUAL 0)
string(STRIP ${cc_dumpmachine_out} cc_dumpmachine_out) # get rid of trailing newline
message(DEBUG "`${CMAKE_C_COMPILER} -dumpmachine` says: \"${cc_dumpmachine_out}\"")
# gcc -dumpmachine and clang -dumpmachine seem to print something like "x86_64-linux-gnu" (gcc)
# or "x64_64-pc-linux-gnu" (clang) or "i686-w64-mingw32" (32bit mingw-w64) i.e. starting with the CPU,
# then "-" and then OS or whatever - so use everything up to first "-"
string(REGEX MATCH "^[^-]+" cpu ${cc_dumpmachine_out})
message(DEBUG " => CPU architecture extracted from that: \"${cpu}\"")
else()
message(WARNING "${CMAKE_C_COMPILER} -dumpmachine failed with error (code) ${cc_dumpmachine_res}")
message(WARNING "will use the (sometimes incorrect) CMAKE_SYSTEM_PROCESSOR (${cpu}) to determine YQ2ARCH")
endif()
endif()
if(cpu STREQUAL "powerpc")
set(cpu "ppc")
elseif(cpu STREQUAL "aarch64")
# "arm64" is more obvious, and some operating systems (like macOS) use it instead of "aarch64"
set(cpu "arm64")
elseif(cpu MATCHES "i.86" OR cpu MATCHES "[xX]86")
set(cpu "i386")
elseif(cpu MATCHES "[aA][mM][dD]64" OR cpu MATCHES "[xX]64")
set(cpu "x86_64")
elseif(cpu MATCHES "[aA][rR][mM].*") # some kind of arm..
# On 32bit Raspbian gcc -dumpmachine returns sth starting with "arm-",
# while clang -dumpmachine says "arm6k-..." - try to unify that to "arm"
if(CMAKE_SIZEOF_VOID_P EQUAL 8) # sizeof(void*) == 8 => must be arm64
set(cpu "arm64")
else() # should be 32bit arm then (probably "armv7l" "armv6k" or sth like that)
set(cpu "arm")
endif()
endif()
set(ARCH "${cpu}")
# END OF workarounds for CMake's poor choices regarding CPU architecture detection
add_definitions(-DYQ2ARCH="${ARCH}") add_definitions(-DYQ2ARCH="${ARCH}")
message(STATUS "Setting YQ2OSTYPE to \"${YQ2OSTYPE}\" and YQ2ARCH to \"${ARCH}\".")
# Systemwide installation of game assets. # Systemwide installation of game assets.
if(${SYSTEMWIDE_SUPPORT}) if(${SYSTEMWIDE_SUPPORT})
add_definitions(-DSYSTEMWIDE) add_definitions(-DSYSTEMWIDE)