Currently, building mlir with the python bindings enabled on Windows in Debug is broken because pybind11, python and cmake don't like to play together. This change normalizes how the three interact, so that the builds can now run and succeed.
The main issue is that python and cmake both make assumptions about which libraries are needed in a Windows build based on the flavor.
- cmake assumes that a debug (or a debug-like) flavor of the build will always require pythonX_d.lib and provides no option/hint to tell it to use a different library. cmake does find both the debug and release versions, but then uses the debug library.
- python (specifically pyconfig.h and by extension python.h) hardcodes the dependency on pythonX_d.lib or pythonX.lib depending on whether `_DEBUG` is defined. This is NOT transparent - it does not show up anywhere in the build logs until the link step fails with `pythonX_d.lib is missing` (or `pythonX.lib is missing`)
- pybind11 tries to "fix" this by implementing a workaround - unless Py_DEBUG is defined, `_DEBUG` is explicitly undefined right before including python headers. This also requires some windows headers to be included differently, so while clever, this is a non-trivial workaround.
mlir itself includes the pybind11 headers (which contain the workaround) AS WELL AS python.h, essentially always requiring both pythonX.lib and pythonX_d.lib for linking. cmake explicitly only adds one or the other, so the build fails.
This change does a couple of things:
- In the cmake files, explicitly add the release version of the python library on Windows builds regardless of flavor. Since Py_DEBUG is not defined, pybind11 will always require release and it will be satisfied
- To satisfy python as well, this change removes any explicit inclusions of Python.h on Windows instead relying on the fact that pybind11 headers will bring in what is needed
There are a few additional things that we could do but I rejected as unnecessary at this time:
- define Py_DEBUG based on the CMAKE_BUILD_TYPE - this will *mostly* work, we'd have to think through multiconfig generators like VS, but it's possible. There doesn't seem to be a need to link against debug python at the moment, so I chose not to overcomplicate the build and always default to release
- similar to above, but define Py_DEBUG based on the CMAKE_BUILD_TYPE *as well as* the presence of the debug python library (`Python3_LIBRARY_DEBUG`). Similar to above, this seems unnecessary right now. I think it's slightly better than above because most people don't actually have the debug version of python installed, so this would prevent breaks in that case.
- similar to the two above, but add a cmake variable to control the logic
- implement the pybind11 workaround directly in mlir (specifically in Interop.h) so that Python.h can still be included directly. This seems prone to error and a pain to maintain in lock step with pybind11
- reorganize how the pybind11 headers are included and place at least one of them in Interop.h directly, so that the header has all of its dependencies included as was the original intention. I decided against this because it really doesn't need pybind11 logic and it's always included after pybind11 is, so we don't necessarily need the python includes
Reviewed By: stellaraccident
Differential Revision: https://reviews.llvm.org/D125284
There is no completely automated facility for generating stubs that are both accurate and comprehensive for native modules. After some experimentation, I found that MyPy's stubgen does the best at generating correct stubs with a few caveats that are relatively easy to fix:
* Some types resolve to cross module symbols incorrectly.
* staticmethod and classmethod signatures seem to always be completely generic and need to be manually provided.
* It does not generate an __all__ which, from testing, causes namespace pollution to be visible to IDE code completion.
As a first step, I did the following:
* Ran `stubgen` for `_mlir.ir`, `_mlir.passmanager`, and `_mlirExecutionEngine`.
* Manually looked for all instances where unnamed arguments were being emitted (i.e. as 'arg0', etc) and updated the C++ side to include names (and re-ran stubgen to get a good initial state).
* Made/noted a few structural changes to each `pyi` file to make it minimally functional.
* Added the `pyi` files to the CMake rules so they are installed and visible.
To test, I added a `.env` file to the root of the project with `PYTHONPATH=...` set as per instructions. Then reload the developer window (in VsCode) and verify that completion works for various changes to test cases.
There are still a number of overly generic signatures, but I want to check in this low-touch baseline before iterating on more ambiguous changes. This is already a big improvement.
Differential Revision: https://reviews.llvm.org/D114679
The purpose of the change is to make clear whether the user is
retrieving the original function or the wrapper function, in line with
the invoke commands. This new functionality is useful for users that
already have defined their own packed interface, so they do not want the
extra layer of indirection, or for users wanting to the look at the
resulting primary function rather than the wrapper function.
All locations, except the python bindings now have a `lookupPacked`
method that matches the original `lookup` functionality. `lookup`
still exists, but with new semantics.
- `lookup` returns the function with a given name. If `bool f(int,int)`
is compiled, `lookup` will return a reference to `bool(*f)(int,int)`.
- `lookupPacked` returns the packed wrapper of the function with the
given name. If `bool f(int,int)` is compiled, `lookupPacked` will return
`void(*mlir_f)(void**)`.
Differential Revision: https://reviews.llvm.org/D114352
We weren't retaining the ctypes closures that the ExecutionEngine was
calling back into, leading to mysterious errors.
Open to feedback about how to test this. And an extra pair of eyes to
make sure I caught all the places that need to be aware of this.
Differential Revision: https://reviews.llvm.org/D110661
* This allows multiple MLIR-API embedding downstreams to co-exist in the same process.
* I believe this is the last thing needed to enable isolated embedding.
Differential Revision: https://reviews.llvm.org/D108605
* For python projects that don't need JIT/ExecutionEngine, cuts the number of files to compile roughly in half (with similar reduction in end binary size).
Differential Revision: https://reviews.llvm.org/D106992
Stella Stamenova