TL;DR: Moving to ScalarType in user extensions and removing deprecated dtypes.
This change _modifies_ the from/to behavior between ScalarType and StableValue! Whereas before, user extensions could only in abstract pass around obfuscated dtypes appearing as int32_ts, now, users can confidently use torch::headeronly::ScalarType in their extensions for major scalar types. This PR enables ABI stability by adding a translation layer through the shim, so that even if the ScalarType enum values change in the future, user extensions need not fear.
Then we add a Tensor scalar_type API which reuses the from/to logic to return to the user a nice ScalarType (vs an abstracted int32_t).
I then changed the test to test the scalar_type API.
This code change required some refactoring because of circular dependencies.
## BC Breaking note
This commit is (narrowly) BC-breaking for unpopular dtypes: `quint*`s, `qint*`s, `Bits*`, `dummy_uint*`s, `dummy_int*`s, `Float8_e8m0fnu`, and `Float4_e2m1fn_x2` in the narrow use case where an extension retrieves a Tensor dtype of the above and passes it into `aoti_torch_call_dispatcher`. As of now, I believe there are 0 users of this use case, so the benefits of this change significantly justify BC-breaking this API.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/160557
Approved by: https://github.com/mikaylagawarecki, https://github.com/malfet
Adds `c_shim_aten.{h/cpp}` and use this for `fill_`
This is the generated `c_shim_aten.cpp` for reference
```cpp
// WARNING: THIS FILE IS AUTOGENERATED BY torchgen. DO NOT MODIFY BY HAND.
// See 7e86a7c015/torchgen/gen.py (L2424-L2436) for details
// This file corresponds to the aten_shimified_ops list in torchgen/aoti/fallback_ops.py
#include <torch/csrc/inductor/aoti_torch/generated/c_shim_aten.h>
#include <torch/csrc/inductor/aoti_torch/utils.h>
#ifndef AT_PER_OPERATOR_HEADERS
#include <ATen/Functions.h>
#include <ATen/CompositeExplicitAutogradFunctions.h>
#include <ATen/CompositeExplicitAutogradNonFunctionalFunctions.h>
#include <ATen/CompositeImplicitAutogradFunctions.h>
#else
#include <ATen/ops/fill.h>
#endif // AT_PER_OPERATOR_HEADERS
using namespace torch::aot_inductor;
AOTITorchError aoti_torch_aten_fill__Scalar(AtenTensorHandle self, double value) {
AOTI_TORCH_CONVERT_EXCEPTION_TO_ERROR_CODE({
at::fill_(
*tensor_handle_to_tensor_pointer(self), value
);
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/158974
Approved by: https://github.com/albanD, https://github.com/janeyx99
