Linker error when building arm84-v8

Android/Java
1

I have the same unsolved issue as Fabio in the old forum:
https://answers.opencv.org/question/229811/opencv4android-build-error-with-arm64-v8a/

I built opencv 4.5.1 which works fine for armeabi-v7a but throws a linker error for arm64-v8

[1241/1467] Linking CXX executable bin/opencv_waldboost_detector
FAILED: bin/opencv_waldboost_detector 
: && /opt/android-ndk-r21e/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ --target=aarch64-none-linux-android21 --gcc-toolchain=/opt/android-ndk-r21e/toolchains/llvm/prebuilt/linux-x86_64 --sysroot=/opt/android-ndk-r21e/toolchains/llvm/prebuilt/linux-x86_64/sysroot  -g -DANDROID -fdata-sections -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security     -fsigned-char -W -Wall -Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point -Wformat -Werror=format-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Winconsistent-missing-override -Wno-delete-non-virtual-dtor -Wno-unnamed-type-template-args -Wno-comment -fdiagnostics-show-option -Qunused-arguments  -fvisibility=hidden -fvisibility-inlines-hidden -O2 -DNDEBUG   -DNDEBUG  -Wl,--exclude-libs,libgcc.a -Wl,--exclude-libs,libgcc_real.a -Wl,--exclude-libs,libatomic.a -static-libstdc++ -Wl,--build-id -Wl,--fatal-warnings -Wl,--no-undefined -Qunused-arguments -Wl,--gc-sections   -Wl,--as-needed modules/xobjdetect/tools/waldboost_detector/CMakeFiles/opencv_waldboost_detector.dir/waldboost_detector.cpp.o  -o bin/opencv_waldboost_detector  lib/arm64-v8a/libopencv_core.a  lib/arm64-v8a/libopencv_imgproc.a  lib/arm64-v8a/libopencv_imgcodecs.a  lib/arm64-v8a/libopencv_videoio.a  lib/arm64-v8a/libopencv_highgui.a  lib/arm64-v8a/libopencv_xobjdetect.a  lib/arm64-v8a/libopencv_videoio.a  -landroid -llog -lmediandk  lib/arm64-v8a/libopencv_imgcodecs.a  3rdparty/lib/arm64-v8a/liblibjpeg-turbo.a  3rdparty/lib/arm64-v8a/liblibwebp.a  3rdparty/lib/arm64-v8a/liblibpng.a  3rdparty/lib/arm64-v8a/liblibtiff.a  3rdparty/lib/arm64-v8a/liblibopenjp2.a  3rdparty/lib/arm64-v8a/libIlmImf.a  lib/arm64-v8a/libopencv_objdetect.a  lib/arm64-v8a/libopencv_calib3d.a  lib/arm64-v8a/libopencv_features2d.a  lib/arm64-v8a/libopencv_imgproc.a  lib/arm64-v8a/libopencv_flann.a  lib/arm64-v8a/libopencv_core.a  3rdparty/lib/arm64-v8a/libzlib.a  3rdparty/lib/arm64-v8a/libcpufeatures.a  3rdparty/lib/arm64-v8a/libittnotify.a  -ldl  -lm  -llog  3rdparty/lib/arm64-v8a/libtegra_hal.a  3rdparty/lib/arm64-v8a/libquirc.a  -latomic -lm && :
lib/arm64-v8a/libopencv_core.a: error adding symbols: Archive has no index; run ranlib to add one
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

system:
ubuntu 20.10
openJDK 13
opencv 4.5.1 w/ contrib
ndk 21e
android sdk 30

Any ideas?

2

cmake seems to cache too much and thus building two different ABIs without deleting CMakeCache.txt between the runs will cause this problem.

This is my working build command:

rm CMakeCache.txt
cmake \
    -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \
    -DANDROID_ABI=arm64-v8a  \
    -DANDROID_NATIVE_API_LEVEL=26 \
    -GNinja \
    -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib/modules \
    -DCMAKE_BUILD_TYPE:STRING=Release \
    -DBUILD_TESTS=FALSE -DBUILD_PERF_TESTS=FALSE \
    -DBUILD_ANDROID_EXAMPLES=FALSE \
    -DCMAKE_CONFIGURATION_TYPES:STRING=Release \
    -DBUILD_opencv_highgui:BOOL=OFF \
    -DBUILD_opencv_js_bindings_generator:BOOL=OFF \
    -DBUILD_opencv_objc_bindings_generator:BOOL=OFF \
    -DINSTALL_CREATE_DISTRIB=ON \
    -DBUILD_DOCS:BOOL=OFF -DBUILD_EXAMPLES:BOOL=ON -DWITH_IPP=OFF -DWITH_MSMF=OFF \
../opencv

ninja
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