Compiling Python 3.4 with emscripten on Ubuntu (linkage errors)

Question

I am trying to build Python 3.4 from source, using emscripten .

I have downloaded and successfully installed emscripten. I have created a build folder outside the source tree. These are the steps I have carried out so far:

1. Run configure: $ emconfigure ../Python-3.4.3/configure --without-threads --without-pymalloc --enable-shared --disable-ipv6 --build=i686-linux-gnu

2. I noticed that a check for LONG_BIT in ../Python-3.4.3/Include/pyport.h conflicts with the #define SIZEOF_LONG defined in one of emscriptens headers, so I have commented out the check in ../Python-3.4.3/Include/pyport.h

3. After running configure successfully, I then run emmmake make in my build folder

4. I check that the built python file is indeed LLVM bytecode by running file python . Having satisfied myself that all is well, I attempt to link the generated libpython3-4.so with the bytecode as follows:

$ llvm-link libpython3.4.so python -o python.bc

I get the following error message:

ERROR: Linking globals named '_Py_open_cloexec_works': symbol multiply defined!

A quick search through the source code shows the symbol is NOT multiply defined:

$ grep -rnw ../Python-3.4.3 -e "_Py_open_cloexec_works" --include=\*.{c,h}
../Python-3.4.3/Python/fileutils.c:33:int _Py_open_cloexec_works = -1;
../Python-3.4.3/Python/fileutils.c:784:    atomic_flag_works = &_Py_open_cloexec_works;
../Python-3.4.3/Modules/posixmodule.c:7702:extern int _Py_open_cloexec_works;
../Python-3.4.3/Modules/posixmodule.c:7725:    int *atomic_flag_works = &_Py_open_cloexec_works;
../Python-3.4.3/Modules/_io/fileio.c:210:extern int _Py_open_cloexec_works;
../Python-3.4.3/Modules/_io/fileio.c:232:    int *atomic_flag_works = &_Py_open_cloexec_works;

So I run nm on libpython3.4.so, to check the exported symbols, and I got the following error message:

nm: libpython3.4.so: File format not recognised

I have run out of ideas now. Can anyone help me solve the linkage issues?

[[ Additional Info ]]

• clang version 3.6.0
• LLVM version 3.6.0svn

Answer 1

Instead of nm , you can use the powerful objdump . Try objdump -t you_file or objdump -T you_file .

Example: objdump -t lib.o