This PR introduces binary search for finding smaller validation errors, when they occur.
We do that by bisecting the sequence of `torch._assert` FX nodes recorded as the source
expression of the translation validator (TV) by `ShapeEnv.evaluate_expr` calls. Then, we
raise the error caused by the earliest node.
In summary, the changes are:
- Call `bisect` on `ValidationError` @ _torch/_dynamo/convert_frame.py_
- Implement the binary search @ _torch/fx/experimental/symbolic_shapes.py_
Edit: moved `ShapeEnv` replay-recording to #107989
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107493
Approved by: https://github.com/ezyang
ghstack dependencies: #107989
This PR stops `SymNode` from mutating (i.e. simplifying) its expression. Instead, the
simplification (without mutation) is deferred to the `SymNode.maybe_as_int` method.
```python
- FakeTensor(size=(s0,), ...)
- FakeTensor(size=(s1, s2, s3), ...)
- Eq(s0, s1 + s2 + s3)
- FakeTensor(size=(s0,), ...)
- FakeTensor(size=(s1, s2, s3), ...)
```
In summary, this PR:
- Replaces `SymNode._expr` by `SymNode.expr`, removing the old property function
- This makes it so `SymNode` instances never update their expression
- Creates `SymNode.simplified_expr()` method for actually calling `ShapeEnv.replace` on
its expression. Note that this doesn't updates `SymNode.expr`
- Changes how `tensor.size()` gets converted to its Python `torch.Size` type
- Instead of calling `SymInt::maybe_as_int()` method, we create a new
`SymInt::is_symbolic()` method for checking whether it is actually a symbolic value
- This is needed so that when we call `tensor.size()` in the Python side, the returned
sequence is faithful to the actual data, instead of possibly simplifying it and
returning an integer
- 2 files needs this modification:
- _torch/csrc/Size.cpp_: for handling `torch.Tensor.size` Python calls
- _torch/csrc/utils/pybind.cpp_: for handling `symint.cast()` C++ calls
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107492
Approved by: https://github.com/ezyang
ghstack dependencies: #107523
This PR wraps `InstructionTranslator` run with a try-catch block so as to run the
translation validation (TV) if it ends up raising an error.
In this context, we run TV so as to catch simplification errors. These may turn
`ShapeEnv.divisible` and `ShapeEnv.replacements` incorrect.
For example: #101173 describes a SymPy simplification bug that doesn't reach TV, since
it's run only in the end of the tracing.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106645
Approved by: https://github.com/ezyang
Previously, you would get an error like
```
Dynamo input and output is a strict subset of traced input/output
```
now you get
```
Cannot export model which references tensors that are neither
buffers/parameters/constants nor are direct inputs. For each tensor, if you'd
like this tensor to be an explicit input, add it as a dummy argument
to the top-level model definition you are exporting; if you would
like its value to be embedded as an exported constant, wrap its access
in a function marked with @assume_constant_result.
G['bulbous_bouffant'], accessed at:
File "test_export.py", line N, in f
return bulbous_bouffant + y
```
This doesn't handle outputs, I'm going to hit that next.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106403
Approved by: https://github.com/tugsbayasgalan
