iOS Simulator (macOS) arm64 compilation failed on linking with NEON error

[Oskar Gargas]

Hello,

I try to compile Tesseract for macOS on arm64. I use the following commands:

```

export LIBS="-lz -lpng -ljpeg -ltiff"

export SDKROOT="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator15.2.sdk"

export CFLAGS="-I/Users/---/Developer/---/libtesseract/tesseract-5.0.1/arm-apple-darwin64/ -arch arm64 -pipe -no-cpp-precomp -isysroot $SDKROOT -mios-simulator-version-min=11.0 -O2 -fembed-bitcode"

export CPPFLAGS=$CFLAGS

export CXXFLAGS="-I/Users/---/Developer/---/libtesseract/tesseract-5.0.1/arm-apple-darwin64/ -arch arm64 -pipe -no-cpp-precomp -isysroot $SDKROOT -mios-simulator-version-min=11.0 -O2 -Wno-deprecated-register"

export LDFLAGS="-L$SDKROOT/usr/lib/ -L/Users/---/Developer/---/libtesseract/simulator/arm-apple-darwin64 -L/Users/---/Developer/---/libtesseract/leptonica-1.82.0/arm-apple-darwin64/src/.libs"

export LIBLEPT_HEADERSDIR=/Users/---/Developer/---/libtesseract/tesseract-5.0.1/arm-apple-darwin64/

export PKG_CONFIG_PATH=/Users/---/Developer/---/libtesseract/leptonica-1.82.0/arm-apple-darwin64/

export CXX="/usr/bin/clang++ --target=arm-apple-darwin64"

export CXX_FOR_BUILD="/usr/bin/clang++ --target=arm-apple-darwin64"

export CC="/usr/bin/clang --target=arm-apple-darwin64"

mkdir -p /Users/---/Developer/---/libtesseract/tesseract-5.0.1/arm-apple-darwin64

cd /Users/---/Developer/---/libtesseract/tesseract-5.0.1/arm-apple-darwin64

ln -s /Users/---/Developer/---/libtesseract/leptonica-1.82.0/src/ leptonica

../configure --host=arm-apple-darwin64 --prefix=`pwd` --enable-shared=no --disable-graphics --disable-legacy --without-curl

```

In configure output I get the following lines (can share full output if its usefull for somebody):

```

checking whether C++ compiler accepts -mfpu=neon... no

checking whether C++ compiler accepts -fopenmp-simd... yes

checking for /usr/bin/clang++ --target=arm-apple-darwin64 option to support OpenMP... unsupported

checking if -framework Accelerate works... yes

```

Then compilation goes ok but I get fail on linking. Is a problem with `Accelerate` not being linked correctly? Something else? Any help will be appreciated.

```

...

CXX src/lstm/libtesseract_lstm_la-series.lo

CXX src/lstm/libtesseract_lstm_la-stridemap.lo

CXX src/lstm/libtesseract_lstm_la-tfnetwork.lo

CXX src/lstm/libtesseract_lstm_la-weightmatrix.lo

CXXLD libtesseract_native.la

CXXLD libtesseract_ccutil.la

CXXLD libtesseract_lstm.la

CXXLD libtesseract.la

CXXLD tesseract

Undefined symbols for architecture arm64:

"tesseract::IntSimdMatrix::intSimdMatrixNEON", referenced from:

tesseract::SIMDDetect::SIMDDetect() in libtesseract.a(libtesseract_la-simddetect.o)

tesseract::SIMDDetect::Update() in libtesseract.a(libtesseract_la-simddetect.o)

"tesseract::DotProductNEON(float const*, float const*, int)", referenced from:

tesseract::SIMDDetect::SIMDDetect() in libtesseract.a(libtesseract_la-simddetect.o)

tesseract::SIMDDetect::Update() in libtesseract.a(libtesseract_la-simddetect.o)

ld: symbol(s) not found for architecture arm64

clang: error: linker command failed with exit code 1 (use -v to see invocation)

make[1]: *** [tesseract] Error 1

make: *** [all-recursive] Error 1

```

FYI: This script worked great for 4.1.3 but it's time to upgrade

[Maria Vilensky]

Hi,

We have the same error, did you end up finding a solution?