LD error: multiple definition of sinRoll when using gcc 10.2

[goekce]

On Archlinux the compilation errors out with default config.mk:

git clone https://github.com/bitcraze/crazyflie-firmware --recursive
cd crazyflie-firmware
cp tools/make/config.mk.example tools/make/config.mk
make -j4
...
/usr/lib/gcc/arm-none-eabi/10.2.0/../../../../arm-none-eabi/bin/ld: bin/sensors_mpu9250_lps25h.o:/home/u/projects/crazyflie/crazyflie-firmware/.//src/hal/src/sensors_mpu9250_lps25h.c:154: multiple definition of `sinRoll'; bin/sensors_bmi088_bmp388.o:/home/u/projects/crazyflie/crazyflie-firmware/.//src/hal/src/sensors_bmi088_bmp388.c:149: first defined here
...
# same error for cosRoll, sinPitch, and cosPitch

I use gcc 10.2:

arm-none-eabi-gcc -v

Using built-in specs.
COLLECT_GCC=arm-none-eabi-gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-none-eabi/10.2.0/lto-wrapper
Target: arm-none-eabi
Configured with: /build/arm-none-eabi-gcc/src/gcc-10.2.0/configure --target=arm-none-eabi --prefix=/usr --with-sysroot=/usr/arm-none-eabi --with-native-system-header-dir=/include --libexecdir=/usr/lib --enable-languages=c,c++ --enable-plugins --disable-decimal-float --disable-libffi --disable-libgomp --disable-libmudflap --disable-libquadmath --disable-libssp --disable-libstdcxx-pch --disable-nls --disable-shared --disable-threads --disable-tls --with-gnu-as --with-gnu-ld --with-system-zlib --with-newlib --with-headers=/usr/arm-none-eabi/include --with-python-dir=share/gcc-arm-none-eabi --with-gmp --with-mpfr --with-mpc --with-isl --with-libelf --enable-gnu-indirect-function --with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm' --with-pkgversion='Arch Repository' --with-bugurl=https://bugs.archlinux.org/ --with-multilib-list=rmprofile
Thread model: single
Supported LTO compression algorithms: zlib zstd
gcc version 10.2.0 (Arch Repository)

and:

arm-none-eabi-ld -v 
GNU ld (GNU Binutils) 2.34

[goekce]

A workaround is adding CFLAGS += -fcommon to config.mk

Apparently newer gcc is more strict about multiple definitions of global variables. The link below has some suggestions how to fix them. It boils down to using extern and declaring the global variables in a single file.

Thanks to: GazL's posting on linuxquestions.org

[ataffanel]

Hi, thanks for the report, this is an actual bug that the new GCC found. I pushed a fix by adding static to these variables since they are, as far as I could tell, local to the file. Could you compile again to see if it now compiles?

[goekce]

@ataffanel wauw thanks for the quick fix! lgtm