[Buildroot] [PATCH v4 1/1] package/spirv-tools: fix build issue

[enki]

---- On Mon, 06 Nov 2023 14:30:12 +0100  Yann E. MORIN  wrote --- 
 > Maciej, All,
 > 
 > 
 > 
 > On 2023-11-06 14:08 +0100, Maciej Grela spake thusly:
 > 
 > > spirv-tools requires a toolchain w/ shared libs, add flag dependency and comment.
 > 
 > > 
 > 
 > > Fixes: http://autobuild.buildroot.net/results/a1f615d2410bffb6fdacc8586761c9def05aafa9
 > 
 > > Fixes: http://autobuild.buildroot.net/results/294ade8c9aa3d650fa5ab6cc34701c4176bc197f
 > 
 > 
 > 
 > Sorry, but I still don't understansd how those two build failures relate
 > 
 > to static builds.
 > 
 >
 > 
 > Both failed build logs are about a broken C++ compiler:
 > 
 > 
 > 
 >     -- Detecting CXX compiler ABI info
 > 
 >     -- Detecting CXX compiler ABI info - failed
 > 
 >     -- Check for working CXX compiler: /usr/bin/clang++
 > 
 >     -- Check for working CXX compiler: /usr/bin/clang++ - broken
 > 
 > 
 > 
 > And indeed, it is not surprising that the host C++ compiler be broken
 > 
 > when doing cross-compilation, as it is used to tentatively build taget
 > 
 > code:
 > 
 > 
 > 
 >     /usr/bin/clang++ --sysroot=/home/thomas/autobuild/instance-1/output-1/host/armeb-buildroot-linux-uclibcgnueabi/sysroot -O3 -DNDEBUG -static  CMakeFiles/cmTC_faefe.dir/testCXXCompiler.cxx.o -o cmTC_faefe
 > 
 >     /usr/bin/ld: /home/thomas/autobuild/instance-1/output-1/host/armeb-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/crt1.o: relocations in generic ELF (EM: 40)
 > 
 >     /usr/bin/ld: /home/thomas/autobuild/instance-1/output-1/host/armeb-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/crt1.o: error adding symbols: file in wrong format
 > 
 >     clang: error: linker command failed with exit code 1 (use -v to see invocation)
 > 
 > 
 > 
 > So, if it really is about a static linking issue, we need more
 > 
 > details...
 > 
 > 

If you take (as an example) the config from a1f615d2410bffb6fdacc8586761c9def05aafa9, enable the C++ support and try to build you get the 
failure caused by ld trying to do a dynamic link with a static library:

[ 54%] Building CXX object source/opt/CMakeFiles/SPIRV-Tools-opt.dir/dataflow.cpp.o
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: /home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/armeb-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libc.a(__uClibc_main.os): in function `__uClibc_fini':
__uClibc_main.c:(.text+0x140): undefined reference to `__fini_array_start'
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: __uClibc_main.c:(.text+0x144): undefined reference to `__fini_array_end'
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: __uClibc_main.c:(.text+0x148): undefined reference to `__fini_array_start'
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: /home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/armeb-buildroot-linux-uclibcgnueabi/sysroot/usr/lib/libc.a(__uClibc_main.os): in function `__uClibc_main':
__uClibc_main.c:(.text+0x430): undefined reference to `__preinit_array_start'
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: __uClibc_main.c:(.text+0x434): undefined reference to `__preinit_array_end'
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: __uClibc_main.c:(.text+0x438): undefined reference to `__init_array_start'
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: __uClibc_main.c:(.text+0x43c): undefined reference to `__init_array_end'
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: libSPIRV-Tools-shared.so: hidden symbol `__preinit_array_start' isn't defined
/home/enki/a1f615d2410bffb6fdacc8586761c9def05aafa9/output/host/lib/gcc/armeb-buildroot-linux-uclibcgnueabi/12.3.0/../../../../armeb-buildroot-linux-uclibcgnueabi/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status
make[4]: *** [source/CMakeFiles/SPIRV-Tools-shared.dir/build.make:1223: source/libSPIRV-Tools-shared.so] Błąd 1
make[3]: *** [CMakeFiles/Makefile2:1091: source/CMakeFiles/SPIRV-Tools-shared.dir/all] Błąd 2

Enabling the shared libs and rebuilding the toolchain fixes this. In other words those two builds fail *both* because of missing C++ support as well as a static-only toolchain. It's just that the missing C++
makes it fail early.

-- 
enki