Cross compilation ignores arch and bits options

[BeayemX]

Godot version:

c23710a

OS/device including version:

Linux Mint 19 - 64 Bit

Issue description:

When trying to cross-compile for Raspberry Pi with the command

scons p=server target=release tools=no arch=arm bits=32

the resulting binary shows x86-64 and 64 bit

$ file bin/godot_server.x11.opt.arm 

bin/godot_server.x11.opt.arm: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=1e49465a67d791c668be1e1007fbb36d319c13c0, not stripped

Edit:

$ gcc --version
gcc (Ubuntu 7.3.0-27ubuntu1~18.04) 7.3.0

[bruvzg]

Out of box Linux cross-compiling does not work at all.

arch option is used only for iOS.
android-arch option is used for Android.
bits is useful only for MinGW, there's some half broken 64/32 x86 Linux cross-compiling code, but it uses hardcoded paths and won't work on half of Linux distros.

You can try to manually set up environment variables for cross compiling, something like (all paths and names may differ):

scons p=server target=release tools=no CXXFLAGS='-D__ARM_ARCH_7__ -D__ARM_ARCH_7A__ -march=armv7-a -mfpu=neon -mfloat-abi=hard' CC='arm-linux-gnueabihf-gcc' CXX='arm-linux-gnueabihf-g++' CPP='arm-linux-gnueabihf-g++' LINKFLAGS='-L/usr/arm-linux-gnueabihf/lib -L/usr/lib/arm-linux-gnueabihf'

This may work for server, but probably won't work for tools/export template (some libs have broken platform detection logic, see #23575 PR).

Native ARM compiling (on real ARM device or inside qemu/chroot) should work without major problems (CXXFLAGS are still necessary for correct optimizations).

[BeayemX]

Thanks for the insight.

Will easier cross compilation be implemented / supported in the future?

btw, yes, building on the raspberry itself is working, it is just really slow (about 4 hours)

[KoBeWi]

Can anyone still reproduce this bug in Godot 3.2.3 or any later release?

[aaronfranke]

This should be fixed as of the proper architecture handling added in #55778. Or it might also need #64366, not sure. If you are still experiencing this issue, feel free to comment, but there has been no activity for years so I am assuming it's fixed.