Re: A different way to build GCC to overcome issues, especially with C++ for embedded systems

[Attila Lendvai]

TL;DR it's probably due to some cmake mess. and i gave up on compiling this; if 
i really want to, i'll do it in a debian chroot.


> > i tried with your gcc … but it errors out with:
> >
> > $ make
> > [ 1%] Linking ASM executable bs2_default.elf
> > arm-none-eabi-gcc: error: nosys.specs: No such file or directory
>
>
> That file is located here: 
> /gnu/store/…-newlib-arm-none-eabi-4.3.0/arm-none-eabi/lib/nosys.specs


that didn't help:

~/workspace/guix/guix/pre-inst-env guix shell gcc-toolchain cmake make 
pkg-config -e '(@ (gnu packages embedded2) 
gcc12-cross-newlib-arm-none-eabi-toolchain)'
cd ~/workspace/bios/pico-serprog
cmake .
COMPILER_PATH=/gnu/store/i9kpjzbagdlpm8bs10gxmm21b271s056-newlib-3.0.0-0.3ccfb40/arm-none-eabi/lib/
 
LDFLAGS=-B/gnu/store/i9kpjzbagdlpm8bs10gxmm21b271s056-newlib-3.0.0-0.3ccfb40/arm-none-eabi/lib/
 make

it leads to the same problem.

but then i tried to compile the pico-sdk subproject as a standalone project, 
and then it succeeds (but fails with a different error later). therefore i 
think it's due to some cmake mess that i don't want to get deeper into. so, the 
rest is just FYI:

git clone https://github.com/raspberrypi/pico-sdk

~/workspace/guix/guix/pre-inst-env guix shell gcc-toolchain cmake make 
pkg-config -e '(@ (gnu packages embedded2) 
gcc12-cross-newlib-arm-none-eabi-toolchain)'

cmake .
make

$ make
[  0%] Building ASM object 
src/rp2_common/boot_stage2/CMakeFiles/bs2_default.dir/compile_time_choice.S.obj
[  0%] Linking ASM executable bs2_default.elf
[  0%] Built target bs2_default
[  0%] Creating directories for 'ELF2UF2Build'
[  0%] No download step for 'ELF2UF2Build'
[  0%] No update step for 'ELF2UF2Build'
[  0%] No patch step for 'ELF2UF2Build'
[  0%] Performing configure step for 'ELF2UF2Build'
-- The C compiler identification is unknown
-- The CXX compiler identification is unknown
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - failed
-- Check for working C compiler: 
/gnu/store/3yqw7js9slid5q3d1f5bpbk92vann109-profile/bin/gcc
-- Check for working C compiler: 
/gnu/store/3yqw7js9slid5q3d1f5bpbk92vann109-profile/bin/gcc - broken
CMake Error at 
/gnu/store/4bn07jsqk6lxp0qdxv7kkc3krz3afnna-cmake-3.25.1/share/cmake-3.25/Modules/CMakeTestCCompiler.cmake:70
 (message):
  The C compiler

    "/gnu/store/3yqw7js9slid5q3d1f5bpbk92vann109-profile/bin/gcc"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: 
/home/alendvai/workspace/bios/pico-sdk/elf2uf2/CMakeFiles/CMakeScratch/TryCompile-fg3QLY

    Run Build 
Command(s):/gnu/store/3yqw7js9slid5q3d1f5bpbk92vann109-profile/bin/make -f 
Makefile cmTC_12bac/fast && make[3]: Entering directory 
'/home/alendvai/workspace/bios/pico-sdk/elf2uf2/CMakeFiles/CMakeScratch/TryCompile-fg3QLY'
    /gnu/store/3yqw7js9slid5q3d1f5bpbk92vann109-profile/bin/make  -f 
CMakeFiles/cmTC_12bac.dir/build.make CMakeFiles/cmTC_12bac.dir/build
    make[4]: Entering directory 
'/home/alendvai/workspace/bios/pico-sdk/elf2uf2/CMakeFiles/CMakeScratch/TryCompile-fg3QLY'
    Building C object CMakeFiles/cmTC_12bac.dir/testCCompiler.c.o
    /gnu/store/3yqw7js9slid5q3d1f5bpbk92vann109-profile/bin/gcc    -o 
CMakeFiles/cmTC_12bac.dir/testCCompiler.c.o -c 
/home/alendvai/workspace/bios/pico-sdk/elf2uf2/CMakeFiles/CMakeScratch/TryCompile-fg3QLY/testCCompiler.c
    as: unrecognized option '--64'
    make[4]: *** [CMakeFiles/cmTC_12bac.dir/build.make:78: 
CMakeFiles/cmTC_12bac.dir/testCCompiler.c.o] Error 1
    make[4]: Leaving directory 
'/home/alendvai/workspace/bios/pico-sdk/elf2uf2/CMakeFiles/CMakeScratch/TryCompile-fg3QLY'
    make[3]: *** [Makefile:127: cmTC_12bac/fast] Error 2
    make[3]: Leaving directory 
'/home/alendvai/workspace/bios/pico-sdk/elf2uf2/CMakeFiles/CMakeScratch/TryCompile-fg3QLY'


the root cause of the messy error message above is the following:

as: unrecognized option '--64'

this happens with the host gcc (or due to some misconfiguration the host gcc is 
used wrongly).

$ file src/rp2_common/boot_stage2/bs2_default.elf
src/rp2_common/boot_stage2/bs2_default.elf: ELF 32-bit LSB executable, ARM, 
EABI5 version 1 (SYSV), statically linked, not stripped
 
--
• attila lendvai
• PGP: 963F 5D5F 45C7 DFCD 0A39
--
“Perfection is achieved, not when there is nothing more to add, but when there 
is nothing left to take away.”
        — Antoine de Saint-Exupery (1900–1944)