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abhiTronix / raspberry-pi-cross-compilers

Latest GCC Cross Compiler & Native (ARM & ARM64) CI generated precompiled standalone toolchains for all Raspberry Pis. 🍇
https://sourceforge.net/projects/raspberry-pi-cross-compilers
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Qt 5.15.2 fails to run on RPi 3B with GCC10.2 crosstoolchain #76

Closed ValentiWorkLearning closed 2 years ago

ValentiWorkLearning commented 3 years ago

I've tried to use GCC10.2 cross-compiler for building Qt following to your guide. Raspberry setup: the latest available Raspberry OS. Host setup: Ubuntu 20.04 with 10.2 cross-compiler.

The building process was completed successfully except a one thing. It seems impossible to launch the compiled binary( I used qopenglwidget from Qt examples) with the 10.2 cross-tools. The maximum available glibcxx under the RPi is GLIBCXX_3.4.25, while the compiled binary requires GLIBCXX_3.4.28.

According to the table here:

https://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html

It seems, that the ABI for running applications which were built using GCC 10.2 cross-compiler is not possible.

I guess, it can be handled somehow, but the maximum available version from the system packages is libstdc++-8-dev.

ValentiWorkLearning commented 3 years ago 
GCC 8.1.0: GLIBCXX_3.4.25, CXXABI_1.3.11

GCC 9.1.0: GLIBCXX_3.4.26, CXXABI_1.3.12

GCC 9.2.0: GLIBCXX_3.4.27, CXXABI_1.3.12

GCC 9.3.0: GLIBCXX_3.4.28, CXXABI_1.3.12

GCC 10.1.0: GLIBCXX_3.4.28, CXXABI_1.3.12

GCC 11.1.0: GLIBCXX_3.4.29, CXXABI_1.3.13

If I'm not mistaking, the cross-compilers above 8.3.0 can't be launched normally in a such environment(or they may produce some hard-to-reproduce cashes)

abhiTronix commented 3 years ago

The maximum available glibcxx under the RPi is GLIBCXX_3.4.25, while the compiled binary requires GLIBCXX_3.4.28.

@ValentiWorkLearning Good finding. Apparently funny thing is that I didn't know till today that GCC on Linux OSes uses patched glibc called libc6 (Glibc (better known as GNU C Library) has a fork for linux which is called libc6. Libc6 is available via apt.).

Currently, Raspbian OS officially provide patched glibc(or libc6) of version 2.28-10+rpi1 which supports GLIBCXX_3.4.25:

pi@raspberrypi:~ $ strings /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 | grep GLIBCXX
GLIBCXX_3.4
GLIBCXX_3.4.1
GLIBCXX_3.4.2
GLIBCXX_3.4.3
GLIBCXX_3.4.4
GLIBCXX_3.4.5
GLIBCXX_3.4.6
GLIBCXX_3.4.7
GLIBCXX_3.4.8
GLIBCXX_3.4.9
GLIBCXX_3.4.10
GLIBCXX_3.4.11
GLIBCXX_3.4.12
GLIBCXX_3.4.13
GLIBCXX_3.4.14
GLIBCXX_3.4.15
GLIBCXX_3.4.16
GLIBCXX_3.4.17
GLIBCXX_3.4.18
GLIBCXX_3.4.19
GLIBCXX_3.4.20
GLIBCXX_3.4.21
GLIBCXX_3.4.22
GLIBCXX_3.4.23
GLIBCXX_3.4.24
GLIBCXX_3.4.25
GLIBCXX_DEBUG_MESSAGE_LENGTH

In contrast to this Official Glibc(by GNU) of version 2.28_(also used by our project binaries)_ instead supports GLIBCXX_3.4.28. I think this project need to build against libc6 source instead of official glibc.

ValentiWorkLearning commented 3 years ago

As I know, glibc cannot be built without rebuilding the whole system via buildroot/yocto because of the dependent software. Probably I'm mistaking. I'll try to find more details

abhiTronix commented 3 years ago

As I know, glibc cannot be built without rebuilding the whole system via buildroot/yocto because of the dependent software.

Nah, you don't need whole system while building glibc itself, you just need the kernel header files. But for cross compiling you need complete system sysroot.

abhiTronix commented 2 years ago

@ValentiWorkLearning OK I've found the problem. You need to define linker flags -Wl,-rpath-link to define exact libs of old glibc while compiling. See this CMAKE file: https://github.com/abhiTronix/raspberry-pi-cross-compilers/wiki/Cross-Compiler-CMake-Usage-Guide-with-rsynced-Raspberry-Pi-32-bit-OS#2-create-picmake-cmake-file

GrubbyHalo commented 1 year ago

@ValentiWorkLearning OK I've found the problem. You need to define linker flags -Wl,-rpath-link to define exact libs of old glibc while compiling. See this CMAKE file: https://github.com/abhiTronix/raspberry-pi-cross-compilers/wiki/Cross-Compiler-CMake-Usage-Guide-with-rsynced-Raspberry-Pi-32-bit-OS#2-create-picmake-cmake-file

This doesn't seem to work for me. I have setup my toolchain.cmake file exactly as you have it wit the -Wl,-rpath- link as you have it and although I can cross compile for stretch using gcc10 on my host machine, it doesn't run on the target and complains about an incompatible libstdc++ version.

Bullseye works because I have cross compiled the same project as I compiled for stretch above with gcc10 and it works I'm not sure about buster. I will try that next

GrubbyHalo commented 1 year ago

whats wierd is that i have 2 cmake projects. they both use exactly the same toolchain file and one runs perfectly on the target but the other one complains about the incompatible stdc++ library being the wrong version