CMake: Fix D3_ARCH, theoretically support Windows on ARM

working around CMake (specifically CMAKE_SYSTEM_PROCESSOR) being useless
and related commits ported from dhewm3, up to including
"CMake: Fix typo in MSVC-specific CPU detection for x64"
This commit is contained in:
Daniel Gibson 2022-05-17 01:29:47 +02:00
parent 14e6d366bf
commit 3170652e11

View file

@ -63,36 +63,67 @@ endif()
# target cpu
set(cpu ${CMAKE_SYSTEM_PROCESSOR})
# 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.. (why am I sticking to this garbage buildsystem?)
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(STATUS "CMAKE_GENERATOR_PLATFORM: ${CMAKE_GENERATOR_PLATFORM}")
if(CMAKE_GENERATOR_PLATFORM STREQUAL "Win32")
set(cpu "x86")
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 ${CMAKE_GENERATOR_PLATFORM}")
endif()
message(STATUS " => CPU architecture extracted from that: \"${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 ${cc_dumpmachine_out} cc_dumpmachine_out) # get rid of trailing newline
message(STATUS "`${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 ${cc_dumpmachine_out})
message(STATUS " => CPU architecture extracted from that: \"${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 D3_ARCH")
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")
set(cpu "x86")
elseif(cpu MATCHES "[aA][mM][dD]64" OR cpu MATCHES "[xX]64")
set(cpu "x86_64")
endif()
# On Windows ${CMAKE_SYSTEM_PROCESSOR} is broken (always returns host CPU)
# which has only been reported >7 years ago (https://cmake.org/pipermail/cmake-developers/2014-September/011405.html)
# so obviously a fix is too much to ask. Here's the special case to make that wonderful platform work;
# except if it's Windows for ARM(64) I guess, no idea how to detect that properly (I don't own such hardware).
if(MSVC)
if(cpu MATCHES ".*[aA][rR][mM].*")
message(FATAL_ERROR "please fix this code to work for Windows on ARM and send a pull request")
endif()
if(CMAKE_CL_64)
set(cpu "x86_64")
else()
set(cpu "x86")
endif()
elseif(DEFINED ENV{MINGW_CHOST})
# looks like it's broken in MinGW32 shells (or 32bit mingw-w64 shells) as well, this should help:
message(STATUS "MINGW_CHOST = $ENV{MINGW_CHOST}")
if($ENV{MINGW_CHOST} MATCHES "^i.86.*")
set(cpu "x86")
elseif($ENV{MINGW_CHOST} MATCHES "^x86_64.*")
set(cpu "x86_64")
else()
message(FATAL_ERROR "please fix this code to work for MINGW_CHOST = $ENV{MINGW_CHOST} and send a pull request!")
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()