Package: gcc-10 Version: 10.2.0-17 Severity: important On mipsel, fenicsx-performance-tests 0.0~git20201022.8913e0f-1 has started failing to build.
The main error is "undefined reference to __divsi3'", as well as __umodsi3 Excerpt from the build log is: [ 71%] Building CXX object CMakeFiles/dolfinx-scaling-test.dir/mesh.cpp.o /usr/bin/c++ -DBOOST_ALL_NO_LIB -DBOOST_CHRONO_DYN_LINK -DBOOST_PROGRAM_OPTIONS_DYN_LINK -DBOOST_TIMER_DYN_LINK -DDOLFINX_VERSION=\"2019.2.9.99\" -DEIGEN_MAX_ALIGN_BYTES=32 -DHAS_SLEPC -I"/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu" -I"/<<PKGBUILDDIR>>/src" -isystem /usr/lib/python3/dist-packages/ffcx/codegeneration -isystem /usr/include/eigen3 -isystem /usr/include/hdf5/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include -isystem /usr/lib/petscdir/petsc3.14/mipsel-linux-gnu-real/include -isystem /usr/lib/slepcdir/slepc3.14/mipsel-linux-gnu-real/include -g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O3 -DNDEBUG -pthread -std=c++17 -march=native -Wall -Wextra -pedantic -Werror -Ofast -o CMakeFiles/dolfinx-scaling-test.dir/main.cpp.o -c "/<<PKGBUILDDIR>>/src/main.cpp" /usr/bin/c++ -DBOOST_ALL_NO_LIB -DBOOST_CHRONO_DYN_LINK -DBOOST_PROGRAM_OPTIONS_DYN_LINK -DBOOST_TIMER_DYN_LINK -DDOLFINX_VERSION=\"2019.2.9.99\" -DEIGEN_MAX_ALIGN_BYTES=32 -DHAS_SLEPC -I"/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu" -I"/<<PKGBUILDDIR>>/src" -isystem /usr/lib/python3/dist-packages/ffcx/codegeneration -isystem /usr/include/eigen3 -isystem /usr/include/hdf5/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include -isystem /usr/lib/petscdir/petsc3.14/mipsel-linux-gnu-real/include -isystem /usr/lib/slepcdir/slepc3.14/mipsel-linux-gnu-real/include -g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O3 -DNDEBUG -pthread -std=c++17 -o CMakeFiles/dolfinx-scaling-test.dir/mesh.cpp.o -c "/<<PKGBUILDDIR>>/src/mesh.cpp" /usr/bin/cc -DBOOST_ALL_NO_LIB -DBOOST_CHRONO_DYN_LINK -DBOOST_PROGRAM_OPTIONS_DYN_LINK -DBOOST_TIMER_DYN_LINK -DDOLFINX_VERSION=\"2019.2.9.99\" -DEIGEN_MAX_ALIGN_BYTES=32 -DHAS_SLEPC -I"/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu" -I"/<<PKGBUILDDIR>>/src" -isystem /usr/lib/python3/dist-packages/ffcx/codegeneration -isystem /usr/include/eigen3 -isystem /usr/include/hdf5/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include -isystem /usr/lib/petscdir/petsc3.14/mipsel-linux-gnu-real/include -isystem /usr/lib/slepcdir/slepc3.14/mipsel-linux-gnu-real/include -g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O3 -DNDEBUG -pthread -march=native -Ofast -o CMakeFiles/dolfinx-scaling-test.dir/Elasticity.c.o -c "/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/Elasticity.c" [ 85%] Building C object CMakeFiles/dolfinx-scaling-test.dir/Poisson.c.o /usr/bin/cc -DBOOST_ALL_NO_LIB -DBOOST_CHRONO_DYN_LINK -DBOOST_PROGRAM_OPTIONS_DYN_LINK -DBOOST_TIMER_DYN_LINK -DDOLFINX_VERSION=\"2019.2.9.99\" -DEIGEN_MAX_ALIGN_BYTES=32 -DHAS_SLEPC -I"/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu" -I"/<<PKGBUILDDIR>>/src" -isystem /usr/lib/python3/dist-packages/ffcx/codegeneration -isystem /usr/include/eigen3 -isystem /usr/include/hdf5/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include/openmpi -isystem /usr/lib/mipsel-linux-gnu/openmpi/include -isystem /usr/lib/petscdir/petsc3.14/mipsel-linux-gnu-real/include -isystem /usr/lib/slepcdir/slepc3.14/mipsel-linux-gnu-real/include -g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O3 -DNDEBUG -pthread -march=native -Ofast -o CMakeFiles/dolfinx-scaling-test.dir/Poisson.c.o -c "/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/Poisson.c" [100%] Linking CXX executable dolfinx-scaling-test /usr/bin/c++ -g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -O3 -DNDEBUG -Wl,-z,relro -pthread CMakeFiles/dolfinx-scaling-test.dir/main.cpp.o CMakeFiles/dolfinx-scaling-test.dir/mesh.cpp.o CMakeFiles/dolfinx-scaling-test.dir/Elasticity.c.o CMakeFiles/dolfinx-scaling-test.dir/Poisson.c.o -o dolfinx-scaling-test -Wl,-rpath,/usr/lib/mipsel-linux-gnu/openmpi/lib:/usr/lib/mipsel-linux-gnu/hdf5/openmpi:/usr/lib/slepcdir/slepc3.14/mipsel-linux-gnu-real/lib:/usr/lib/petscdir/petsc3.14/mipsel-linux-gnu-real/lib: /usr/lib/mipsel-linux-gnu/libdolfinx_real.so.2019.2.9.99 /usr/lib/mipsel-linux-gnu/libboost_program_options.so.1.71.0 /usr/lib/mipsel-linux-gnu/libboost_timer.so.1.71.0 /usr/lib/mipsel-linux-gnu/libboost_chrono.so.1.71.0 /usr/lib/mipsel-linux-gnu/openmpi/lib/libmpi_cxx.so /usr/lib/mipsel-linux-gnu/openmpi/lib/libmpi.so /usr/lib/mipsel-linux-gnu/hdf5/openmpi/libhdf5.so /usr/lib/mipsel-linux-gnu/libsz.so /usr/lib/mipsel-linux-gnu/libz.so /usr/lib/mipsel-linux-gnu/libdl.so /usr/lib/mipsel-linux-gnu/libm.so /usr/lib/slepcdir/slepc3.14/mipsel-linux-gnu-real/lib/libslepc_real.so /usr/lib/petscdir/petsc3.14/mipsel-linux-gnu-real/lib/libpetsc_real.so /usr/bin/ld: CMakeFiles/dolfinx-scaling-test.dir/main.cpp.o: in function `void Eigen::internal::check_rows_cols_for_overflow<-1>::run<int>(int, int)': /usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: undefined reference to `__divsi3' /usr/bin/ld: /usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: undefined reference to `__divsi3' /usr/bin/ld: /usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: undefined reference to `__divsi3' /usr/bin/ld: /usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: undefined reference to `__divsi3' /usr/bin/ld: /usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: undefined reference to `__divsi3' /usr/bin/ld: CMakeFiles/dolfinx-scaling-test.dir/main.cpp.o:/usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: more undefined references to `__divsi3' follow /usr/bin/ld: CMakeFiles/dolfinx-scaling-test.dir/main.cpp.o: in function `unsigned int std::__detail::__to_chars_len<unsigned int>(unsigned int, int)': /usr/include/c++/10/bits/charconv.h:61: undefined reference to `__udivsi3' /usr/bin/ld: /usr/include/c++/10/bits/charconv.h:62: undefined reference to `__udivsi3' /usr/bin/ld: CMakeFiles/dolfinx-scaling-test.dir/main.cpp.o: in function `void std::__detail::__to_chars_10_impl<unsigned int>(char*, unsigned int, unsigned int)': /usr/include/c++/10/bits/charconv.h:86: undefined reference to `__umodsi3' /usr/bin/ld: /usr/include/c++/10/bits/charconv.h:86: undefined reference to `__umodsi3' /usr/bin/ld: /usr/include/c++/10/bits/charconv.h:87: undefined reference to `__udivsi3' /usr/bin/ld: /usr/include/c++/10/bits/charconv.h:87: undefined reference to `__udivsi3' /usr/bin/ld: CMakeFiles/dolfinx-scaling-test.dir/main.cpp.o: in function `void Eigen::internal::check_rows_cols_for_overflow<-1>::run<int>(int, int)': /usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: undefined reference to `__divsi3' /usr/bin/ld: /usr/include/eigen3/Eigen/src/Core/PlainObjectBase.h:46: undefined reference to `__divsi3' collect2: error: ld returned 1 exit status Full log at https://buildd.debian.org/status/logs.php?pkg=fenicsx-performance-tests&arch=mipsel https://buildd.debian.org/status/fetch.php?pkg=fenicsx-performance-tests&arch=mipsel&ver=0.0%7Egit20201022.8913e0f-1&stamp=1605323049&raw=0 The error message doesn't really make sense in the context of fenicsx-performance-tests itself, or in eigen3 where the error is triggered (noting also it is triggered in /usr/include/c++/10/bits/charconv.h) Discussing at #debian-devel on IRC, Jessica Clarke suggests the use of -march=native may be involved. gcc docs say this flag is supposed to be supported on mipsel. Is there a bug here selecting the appropriate processor? Jessica's diagnosis from IRC: <jrtc27> uh yeah that shouldn't be happening, mipsel can do division in hardware so doesn't have the si libfuncs (only the di ones for 64-bit integers) ... <jrtc27> my guess would be that something about the loongson3a-specific division instructions breaks ... <jrtc27> it'd be interesting to see what gcc things -march=native is on that buildd <jrtc27> there's some hairy logic that disables the traditional mips mul/div on loongson architectures <jrtc27> with the intent that the loongson-specific patterns then match ... <jrtc27> -march=gs464 -mno-loongson-ext <jrtc27> tor -march=loongson3a -mno-loongson-ext <jrtc27> *or <jrtc27> that gets gcc to emit libcalls, not hard float instructions <Rizzer> could it be a bug in the latest gcc10? march=native picking the wrong processor? <jrtc27> there's at least one bug in gcc <Rizzer> nothing mips-specific in the changelog for recent uploads though <jrtc27> I don't know what exactly -march=native decides; maybe -mno-loongson-ext is intended, maybe not <jrtc27> but regardless, loongson3a without loongson-ext *should* fall back on the traditional mips instructions <jrtc27> ISA_AVOID_DIV_HILO however doesn't account for TARGET_LOONGSON_EXT being false <jrtc27> when TARGET_GS464 is true <jrtc27> as the loongson division instructions are gated on TARGET_LOONGSON_2EF || TARGET_LOONGSON_EXT <Rizzer> How certain is it a bug in gcc-10? Is it certain enough for me to file a bug report against gcc-10 ? <jrtc27> 99% <jrtc27> well, 100% really <jrtc27> if it means to use the libcalls in that weird case, it needs to include the functions in libgcc <jrtc27> but I'm 99.99999% sure it doesn't want to use soft ... division Jessica prepared a minimal test case to reproduce the problem at http://paste.debian.net/1172394/ (sid_mipsel-dchroot)$ echo 'int div(int x, int y) { return x / y; } int mod(int x, int y) { return x % y; }' | cc -x c - -o - -S -march=loongson3a -mno-loongson-ext | grep si3 .globl __divsi3 lw $2,%call16(__divsi3)($28) .reloc 1f,R_MIPS_JALR,__divsi3 .globl __modsi3 lw $2,%call16(__modsi3)($28) .reloc 1f,R_MIPS_JALR,__modsi3
