Using FUNCTION_NAME on add_halide_library breaks Python shared objects

[mihai-mc]

Issue Description

The following CMake configuration compiles, but the resulting shared object is not usable in Python!

Not using FUNCTION_NAME in add_halide_library results in usable shared objects being created.

. . .
add_halide_library(
    dummy_library
    FROM DummyGenerators
    GENERATOR Dummy
    FUNCTION_NAME myDummyFunction
    AUTOSCHEDULER "Halide::Adams2019"
    PARAMS auto_schedule=true
    SCHEDULE OUTVAR
    TARGETS ${Halide_CMAKE_TARGET}
    PYTHON_EXTENSION dummy_library_PYEXT
)

Python3_add_library(
    dummy_library_py
    MODULE
        ${CMAKE_BINARY_DIR}/dummy_library.py.cpp
        ${CMAKE_BINARY_DIR}/dummy_library.runtime.o
        ${CMAKE_BINARY_DIR}/dummy_library.o
)
. . .

Python Error message

    import dummy_library_py
ImportError: dynamic module does not define module export function (PyInit_dummy_library)

System Information

• OS: macOS 11.5.2
• CMake: 3.21.1
• Python: 3.9.6
• Halide: 12.0.1

[steven-johnson]

I'm confused; the description says "using Function name" but the example is clearly specifying FUNCTION_NAME

[mihai-mc]

Hi @steven-johnson ! The description says "Not using FUNCTION_NAME".

To rephrase: using FUNCTION_NAME results in Shared Objects that CANNOT be used in Python [because of the error above].

Hope this helps 👍🏻