Issue 35997: ImportError: dlopen failed: cannot locate symbol "PyBool_Type" (original) (raw)

Created on 2019-02-14 20:36 by muhzi, last changed 2022-04-11 14:59 by admin.

Messages (8)
msg335560 - (view)	Author: (muhzi)	Date: 2019-02-14 20:36
I cross compiled python for android x86_64, and the interpreter works fine, no problems. But when I compiled some other extension and try to import it. I get an import error as such the imported shared library fails to locate the symbol "PyBool_Type". ImportError: dlopen failed: cannot locate symbol "PyBool_Type" referenced by .... The extension was compiled with -I && -L flags pointing to the Python installation include and lib folders.
msg335563 - (view)	Author: Stéphane Wirtel (matrixise) *	Date: 2019-02-14 21:06
Can you see the symbols when you use nm or readelf?
msg335565 - (view)	Author: Stéphane Wirtel (matrixise) *	Date: 2019-02-14 21:11
if you have compiled python with --enable-shared you will get a lib/libpython3.Xdm.so file and you can use nm -D lib/libpython3.Xdm.so | grep PyBool_Type nm --debug-syms lib/libpython3.8dm.so	grep PyBool 0000000000077696 T PyBool_FromLong 0000000000328d20 D PyBool_Type I think it's a problem with your compilation. Could you explain how do you cross-compile for android? Thank you
msg335567 - (view)	Author: (muhzi)	Date: 2019-02-14 21:26
Yes, the symbols are there. And here is how I cross compiled Python: export CC="${ANDROID_TARGET}${ANDROID_API}-clang" export CXX="$CC++" # environment variables for binary utils.. export AR="$BIN_UTILS_PREFIX-ar" export LD="$BIN_UTILS_PREFIX-ld" export AS="$BIN_UTILS_PREFIX-as" export STRIP="$BIN_UTILS_PREFIX-strip" export RANLIB="$BIN_UTILS_PREFIX-ranlib" export READELF="$BIN_UTILS_PREFIX-readelf" # compiler and linker flags export CFLAGS="-fPIE -fPIC" export LDFLAGS="-fuse-ld=lld -Wl,--rpath=../lib" export CONFIG_SITE="config.site" CONFIG_BUILD="$(uname -m)-linux-gnu" CONFIG_ARGS="--enable-shared --disable-ipv6" CONFIG_PREFIX="$PYTHON_PATH/output/$ARCH-android" PYTHONPATH/configure−−host=PYTHON_PATH/configure --host=PYTHONPATH/configure−−host=ANDROID_TARGET --build=$CONFIG_BUILD --prefix=$CONFIG_PREFIX CONFIGARGSmake−CCONFIG_ARGS make -C CONFIGARGSmake−CPYTHON_PATH make -C $PYTHON_PATH install
msg335568 - (view)	Author: Stéphane Wirtel (matrixise) *	Date: 2019-02-14 21:37
Thank you, but I think there is missing info with your script. Do you have a shell script to share? What are the values of: ANDROID_TARGET ANDROID_API CC++ BIN_UTILS_PREFIX etc... For example, if I want to use a docker image on my Fedora, how can I compile Python for Android from my Fedora or Debian x86? Thank you
msg335570 - (view)	Author: (muhzi)	Date: 2019-02-14 21:54
OK, I uploaded it. I give the path for NDK then it determines those values for the target architecture, in my case I use it for x86_64.
msg335625 - (view)	Author: Xavier de Gaye (xdegaye) *	Date: 2019-02-15 17:33
It is not yet possible to cross-compile python extensions. The reason is that _init_posix() in Lib/sysconfig.py still reads the sysconfigdata module of the native compiler instead of the sysconfigdata of the cross-built one. See the patch in issue #28833.
msg335665 - (view)	Author: (muhzi)	Date: 2019-02-16 02:31
Ah! I used the option -Bsymbolic while linking the extension to make it work and it did, but I figure it is not ideal. I will be checking that patch!