Subsumes https://github.com/pytorch/pytorch/pull/110794
Fixes https://github.com/pytorch/pytorch/issues/110315
This is not really a 100% sound fix, a deeper analysis of the bug can be found at https://docs.google.com/document/d/1y-nRAPdbZEji52MPKYzC0U3VhvW9yEAEDqP5t5GhWZ0/edit
The general idea behind the fix here is that we are going to play fast and loose with user defined classes: as Dynamo is written today, we are willing to pull out these types and directly manipulate them (e.g., look at their `__mro__`, etc) without an intervening VariableTracker. As such, if I use `python_type` to extract out the Python type of a VT or if I am manually reading out the `__bases__` of a type, which may be a user defined class, if it is sourceless, all I need to do is use SourcelessBuilder instead of ConstantVariable to make sure I wrap it into the correct VT class.
The approach in https://github.com/pytorch/pytorch/pull/110794 was "more correct", but we'd have to go substantially further to get it all working. So I am doing this to unblock suo for now.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/113390
Approved by: https://github.com/suo
Recently we updated the `export` API to take an experimental `dynamic_shapes` argument that was meant to subsume the existing `constraints` argument.
This PR deprecates `constraints` (with a warning on its use, but without actually removing it). Simultaneously it replaces all uses of `constraints` in docs, examples, and tests with corresponding uses of `dynamic_shapes` (preserving behavior). This exercise fortunately revealed some minor bugs in the implementation which have also been fixed in this PR.
Some uses of `constraints` still remain, e.g., when `torch._dynamo.export` is called directly. (Meta-internal uses will be updated in a separate diff.)
Differential Revision: D49676049
Pull Request resolved: https://github.com/pytorch/pytorch/pull/110143
Approved by: https://github.com/tugsbayasgalan
Solving #105242.
During export, the exported function's signature changes multiple times. Suppose we'd like to export f as shown in following example:
```python
def f(arg1, arg2, kw1, kw2):
pass
args = (arg1, arg2)
kwargs = {"kw2":arg3, "kw1":arg4}
torch.export(f, args, kwargs)
```
The signature changes mutiple times during export process in the following order:
1. **gm_torch_level = dynamo.export(f, *args, \*\*kwargs)**. In this step, we turn all kinds of parameters such as **postional_only**, **var_positioinal**, **kw_only**, and **var_kwargs** into **positional_or_kw**.It also preserves the positional and kword argument names in original function (i.e. f in this example) [here](https://github.com/pytorch/pytorch/blob/main/torch/_dynamo/export.py#L546C13-L546C27). The order of kwargs will be the **key order** of kwargs (after python 3.6, the order is the insertion of order of keys) instead of the original function signature and the order is baked into a _orig_args varaible of gm_torch_level's pytree info. So we'll have:
```python
def gm_torch_level(arg1, arg2, kw2, kw1)
```
Such difference is acceptable as it's transparent to users of export.
2. **gm_aot_export = aot_export_module(gm_torch_level, pos_or_kw_args)**. In this step, we need to turn kwargs into positional args in the order of how gm_torch_level expected, which is stored in _orig_args. The returned gm_aot_export has the graph signature of flat_args, in_spec = pytree.tree_flatten(pos_or_kw_args):
``` python
flat_args, _ = pytree.tree_flatten(pos_or_kw_args)
def gm_aot_export(*flat_args)
```
3. **exported_program(*args, \*\*kwargs)**. The epxorted artifact is exported_program, which is a wrapper over gm_aot_export and has the same calling convention as the original function "f". To do this, we need to 1. specialize the order of kwargs into pos_or_kw_args and 2. flatten the pos_or_kw_args into what gm_aot_export expected. We can combine the two steps into one with :
```python
_, in_spec = pytree.tree_flatten((args, kwargs))
# Then during exported_program.__call__(*args, **kwargs)
flat_args = fx_pytree.tree_flatten_spec((args, kwargs), in_spec)
```
, where kwargs is treated as a normal pytree whose keyorder is preserved in in_spec.
Implementation-wise, we treat _orig_args in dynamo exported graph module as single source of truth and kwags are ordered following it.
Test plan:
See added tests in test_export.py.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105337
Approved by: https://github.com/angelayi, https://github.com/tugsbayasgalan
