Replaces `view_func()` closures with a reified `ViewFunc` data structure. Codegen generates a `ViewFunc` subclass for each view op (e.g. `NarrowViewFunc`) containing state needed to reconstruct the view. The `ViewFunc` API allows for querying and hot-swapping any `SymInt`s or `Tensors` in the state through `get_symints()` / `get_tensors()` / `clone_and_set()`, which will be essential for fake-ification later on.
```cpp
/// Base class for view functions, providing reapplication of a view on a new base.
/// Each view op should get a codegenerated subclass of this class containing
/// any state needed to reconstruct the view. The class also provides convenience
/// accessors for saved SymInts / tensor state. This is useful for e.g. fake-ification,
/// where we want to use symbolic values or fake tensors instead.
struct TORCH_API ViewFunc {
virtual ~ViewFunc() {}
/// Returns any SymInts in the saved state.
virtual std::vector<c10::SymInt> get_symints() const { return {}; }
/// Returns the number of SymInts in the saved state.
virtual size_t num_symints() const { return 0; }
/// Returns any tensors in the saved state.
virtual std::vector<at::Tensor> get_tensors() const { return {}; }
/// Returns the number of tensors in the saved state.
virtual size_t num_tensors() const { return 0; }
/// Reapplies the view on the given base using the saved state.
virtual at::Tensor operator()(const at::Tensor&) const = 0;
/// Returns a clone of this ViewFunc, optionally with the specified saved state.
virtual std::unique_ptr<ViewFunc> clone_and_set(
std::optional<std::vector<c10::SymInt>> = c10::nullopt,
std::optional<std::vector<at::Tensor>> = c10::nullopt) const = 0;
protected:
/// Sets the values of any SymInts in the saved state. The input vector size must
/// match the number of SymInts in the saved state (i.e. the size of the list
/// returned by get_symints()).
virtual void set_symints(std::vector<c10::SymInt>) {}
/// Sets the values of any Tensors in the saved state. The input vector size must
/// match the number of Tensors in the saved state (i.e. the size of the list
/// returned by get_tensors()).
virtual void set_tensors(std::vector<at::Tensor>) {}
};
```
New codegen files:
* `torch/csrc/autograd/generated/ViewFunc.h`
* `torch/csrc/autograd/generated/ViewFuncs.cpp`
The templates for these also contains impls for `ChainedViewFunc` and `ErroringViewFunc` which are used in a few places within autograd.
Example codegen for `slice.Tensor`:
```cpp
// torch/csrc/autograd/generated/ViewFuncs.h
#define SLICE_TENSOR_VIEW_FUNC_AVAILABLE
struct SliceTensorViewFunc : public torch::autograd::ViewFunc {
SliceTensorViewFunc(int64_t dim, c10::optional<c10::SymInt> start, c10::optional<c10::SymInt> end, c10::SymInt step) : dim(dim), start(start), end(end), step(step)
{};
virtual ~SliceTensorViewFunc() override {};
virtual std::vector<c10::SymInt> get_symints() const override;
virtual size_t num_symints() const override;
virtual std::vector<at::Tensor> get_tensors() const override;
virtual size_t num_tensors() const override;
virtual at::Tensor operator()(const at::Tensor&) const override;
virtual std::unique_ptr<ViewFunc> clone_and_set(
std::optional<std::vector<c10::SymInt>> = c10::nullopt,
std::optional<std::vector<at::Tensor>> = c10::nullopt) const override;
protected:
virtual void set_symints(std::vector<c10::SymInt>) override;
virtual void set_tensors(std::vector<at::Tensor>) override;
private:
int64_t dim;
c10::optional<c10::SymInt> start;
c10::optional<c10::SymInt> end;
c10::SymInt step;
};
...
// torch/csrc/autograd/generated/ViewFuncs.cpp
std::vector<c10::SymInt> SliceTensorViewFunc::get_symints() const {
::std::vector<c10::SymInt> symints;
symints.reserve((start.has_value() ? 1 : 0) + (end.has_value() ? 1 : 0) + 1);
if(start.has_value()) symints.insert(symints.end(), *(start));
if(end.has_value()) symints.insert(symints.end(), *(end));
symints.push_back(step);
return symints;
}
size_t SliceTensorViewFunc::num_symints() const {
return static_cast<size_t>((start.has_value() ? 1 : 0) + (end.has_value() ? 1 : 0) + 1);
}
void SliceTensorViewFunc::set_symints(std::vector<c10::SymInt> symints) {
TORCH_INTERNAL_ASSERT(symints.size() == num_symints());
auto i = 0;
if(start.has_value()) start = symints[i];
i += (start.has_value() ? 1 : 0);
if(end.has_value()) end = symints[i];
i += (end.has_value() ? 1 : 0);
step = symints[i];
}
std::vector<at::Tensor> SliceTensorViewFunc::get_tensors() const {
::std::vector<at::Tensor> tensors;
return tensors;
}
size_t SliceTensorViewFunc::num_tensors() const {
return static_cast<size_t>(0);
}
void SliceTensorViewFunc::set_tensors(std::vector<at::Tensor> tensors) {
TORCH_INTERNAL_ASSERT(tensors.size() == num_tensors());
}
at::Tensor SliceTensorViewFunc::operator()(const at::Tensor& input_base) const {
return at::_ops::slice_Tensor::call(input_base, dim, start, end, step);
}
std::unique_ptr<ViewFunc> SliceTensorViewFunc::clone_and_set(
std::optional<std::vector<c10::SymInt>> symints,
std::optional<std::vector<at::Tensor>> tensors) const {
auto output = std::make_unique<SliceTensorViewFunc>(dim, start, end, step);
if (symints.has_value()) {
output->set_symints(std::move(*(symints)));
}
if (tensors.has_value()) {
output->set_tensors(std::move(*(tensors)));
}
return output;
}
```
The `_view_func()` / `_view_func_unsafe()` methods now accept two additional (optional) args for `symint_visitor_fn` / `tensor_visitor_fn`. If these are defined, they are expected to be python callables that operate on a single SymInt / tensor and return a new one. This allows for the hot-swapping needed during fake-ification.
For testing, there are extensive pre-existing tests, and I added a test to ensure that hot-swapping functions correctly.
```sh
python test/test_autograd.py -k test_view_func_replay
python test/test_ops.py -k test_view_replay
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/118404
Approved by: https://github.com/ezyang
Part 2 of implementation for general [subclass view fake-ification](https://docs.google.com/document/d/1C5taWiplmX7nKiURXDOAZG2W5VNJ2iV0fQFq92H0Cxw).
Details:
* Codegen `rev_view_func()` alongside `view_func()`
* Reverse view_func gives you a "base" from a "view": `rev_view_func(new_view) -> new_base` AKA it plays the original view backwards
* Utilizes the functional inverses defined in `FunctionalInverses.cpp`, passing `InverseReturnMode::AlwaysView`
* Manually implements functional inverses for `narrow()` and `chunk()`
* **NB: Multi-output views now set view_func() / rev_view_func() for each of the output views!**
* Due to this, the `as_view()` overload that operates on a list of views is scrapped in favor of iteration via codegen
Example codegen in `ADInplaceOrViewTypeN.cpp`:
```cpp
at::Tensor narrow(c10::DispatchKeySet ks, const at::Tensor & self, int64_t dim, c10::SymInt start, c10::SymInt length) {
auto _tmp = ([&]() {
at::AutoDispatchBelowADInplaceOrView guard;
return at::_ops::narrow::redispatch(ks & c10::after_ADInplaceOrView_keyset, self, dim, start, length);
})();
std::function<at::Tensor(const at::Tensor&)> func=nullptr;
std::function<at::Tensor(const at::Tensor&)> rev_func=nullptr;
if (false || !self.unsafeGetTensorImpl()->support_as_strided() ||
c10::AutogradState::get_tls_state().get_view_replay_enabled()) {
func = [=](const at::Tensor& input_base) {
return at::_ops::narrow::call(input_base, dim, start, length);
};
rev_func = [=](const at::Tensor& input_view) {
// NB: args from narrow() signature are passed along to the inverse
return at::functionalization::FunctionalInverses::narrow_copy_inverse(self, input_view, at::functionalization::InverseReturnMode::AlwaysView, dim, start, length);
};
}
auto result = as_view(/* base */ self, /* output */ _tmp, /* is_bw_differentiable */ true, /* is_fw_differentiable */ true, /* view_func */ func, /* rev_view_func */ rev_func, /* creation_meta */ InferenceMode::is_enabled() ? CreationMeta::INFERENCE_MODE : (at::GradMode::is_enabled() ? CreationMeta::DEFAULT : CreationMeta::NO_GRAD_MODE));
return result;
}
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/115894
Approved by: https://github.com/soulitzer
I'm not sure why we needed two overloads previously, let's find out! Removing the int overload is load bearing because it now forces specialization on SymInt arguments instead of falling through to the SymInt overload, see new test.
I decided NOT to allow storage offset simultaneously with None strides.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/114236
Approved by: https://github.com/albanD
Currently meta_utils relies on as_strided when handling the view case (recursively meta-ify the base, and then do as_strided to simulate the view), but NestedTensor does not support as_strided today (though maybe it could?), so what we want to do instead is call Tensor. _view_func. Conveniently, _view_func IS always available for nested tensors.
A detail to note is that _view_func actually incurs a guard because it needs to perform some metadata checks to make sure the view is still valid. This PR adds Tensor._unsafe_view_func which can avoid that.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/112205
Approved by: https://github.com/jbschlosser
This PR enables the misc-XX checks in clang-tidy. Meanwhile, I excluded some of them that require a lot of code changes and have no immediate benefits. Some additional fixes and suppression were also given.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/110283
Approved by: https://github.com/albanD
Summary:
FBGEMM uses `self.iter.is_cuda` to check if the tensor is for CUDA. This diff enables similar feature `self.iter.is_mtia` for tensors with MTIA device key.
Test Plan: See diff D48693225
Reviewed By: jackm321
Differential Revision: D48809191
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108310
Approved by: https://github.com/albanD
This is tested by AOTAutograd later in the stack, but I can add direct tests if anyone wants them.
Previously, the second overload of `_make_wrapper_subclass` (which supports dynamic shapes) would just always return a wrapper tensor that reported as being on `cpu`. This updates it to properly respect the `device` arg that was passed in.
At first I thought about doing this the same way that FakeTensor does it (override device to do a custom impl), but that seemed overly complicated. Since the subclass is a wrapper, we can just bake in the value on the wrapper.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107926
Approved by: https://github.com/ezyang
ghstack dependencies: #107915, #107916
This is mostly a minor fix on top of @soulitzer's PR https://github.com/pytorch/pytorch/pull/107839.
(1) `strides` wasn't going through the new `set_tensor_attr_with_capsule` flow
(2) The dynamic shapes overload for `_make_wrapper_subclass` currently errors when you try to use custom sizes - I removed the error
(3) added a test
I need this later because I'm adding a `__torch_dispatch__` `FunctionalTensor` wrapper subclass, that needs to support dynamic shapes, and also plumb metadata calls to its inner tensor later.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107916
Approved by: https://github.com/ezyang, https://github.com/soulitzer
ghstack dependencies: #107915
There is already some support for plumbing `__torch_dispatch__` tensor subclasses through dynamo, but this PR beefs it up a bit and adds a test. In particular:
(1) Fakeifying tensor subclasses didn't properly set autograd metadata (requires_grad, is_leaf) on the newly fakeified wrapper subclass. I don't actually have a test for this in this PR, but it's tested pretty heavily later in my aot autograd tests
(2) Fakeifying tensor subclasses didn't properly track source information for dynamic shapes on the inner tensors. I added a new `WrapperSubclassFieldSource` subclass, that represents a source coming from a tensor field on a wrapper subclass, which I use in the fakeifying logic, and again in symbolic_shapes.py to generate proper guards.
(3) `_make_wrapper_subclass()` marginally updated this code to work better with dynamic shapes. One thing that's a bit weird about `_make_wrapper_subclass`: it has two overloads, and the first explicitly does not support dynamic shapes (and the second.. does not support kwargs). I think that later we probably want to consolidate / at least make the first overload work with dynamic shapes, but I didn't want to handle that in this PR (so these smaller changes seemed like a strict improvement).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107415
Approved by: https://github.com/ezyang
Previously, the first overload of `_make_wrapper_subclass` returned a tensor that **always** advertised as having a non-resizeable storage. Eventually, we'll need it be advertise as resizeable for functionalization to work (since functionalization occasionally needs to resize storages).
Not directly tested in this PR (tested more heavily later in aot dispatch, but if someone wants me to write a more direct test I can add one).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107416
Approved by: https://github.com/ezyang, https://github.com/albanD
ghstack dependencies: #107417
Running an operator registered in python returning a symint will result in the following error:
```
RuntimeError: Unable to cast Python instance of type <class 'torch.SymInt'> to C++ type 'long'
```
The interaction of 2 things make the issue being triggered:
- We use boxed kernel here. For boxed kernel, we need convert py::object to IValue in torch/csrc/autograd/python_variable.cpp pushPyOutToStack .
- In the schema parsing code in torch/csrc/jit/frontend/schema_type_parser.cpp SchemaTypeParser::parseFakeAndRealType , if a SymInt is found, we register a Int type instead (not sure why we do this), and register SymInt as the real type.
The result is we would convert an SymInt to int in pushPyOutToStack and cause the issue.
The fix is to use real type when we convert py::object to IValue.
BTW, registering the same op using C++ API does not trigger the issue.
```
TORCH_LIBRARY(clib, m) {
m.def("sqsum(SymInt a, SymInt b) -> SymInt", [](SymInt a, SymInt b) -> SymInt {
return a * a + b * b;
});
}
```
The reason is, the kernel registered in C++ is unboxed kernel and it does not trigger the code path above that converts an py::object to IValue.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95240
Approved by: https://github.com/larryliu0820, https://github.com/ezyang
Not only is this change usually shorter and more readable, it also can yield better performance. size() is not always a constant time operation (such as on LinkedLists), but empty() always is.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/93236
Approved by: https://github.com/malfet
This reverts commit e525f433e1.
Original PR: #85849
Fixes #ISSUE_NUMBER
In addition to reverting the revert, this PR:
- defines the virtual destructor of FunctionPreHook in the header. Why? Presumably the internal build imports the header from somewhere, but does not have function_hooks.cpp (where the virtual destructor was previously defined) in the same compilation unit.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/92559
Approved by: https://github.com/albanD
Addresses: https://github.com/pytorch/pytorch/issues/35802
Design doc: https://docs.google.com/document/d/19xSib7FFknRQ5f3ptGFUmiOt3BrgXSUlTQH2xMcZJYg/edit#
### Changes in this PR
#### Implementation
- We have now have 3 fields: pre_hooks, retains_grad_hooks, and tensor_pre_hooks so that we can more precisely define their ordering and when they are executed.
- Since retains grad uses an entirely new field, we cannot reuse the old retains grad, logic. We refactor retains grad to call directly into the variable.cpp logic. Other logic in variable.cpp that handle cpp hooks must also be updated.
#### Hooks ordering and execution:
- Defines pre-hooks registered on tensor to run before pre-hooks registered on grad_fn
- Updates pre-hooks registered on tensor to always run, even if they are the inputs= to .grad()
- Post hooks (and pre hooks) can now observe the modifications to gradient by the tensor pre hook
#### Retains grad hooks
- retains grad hooks always execute last, even if there are other tensor pre-hooks registered
#### Unchanged:
- pre_hooks registered to grad_fn aren't expected to execute if they are the inputs= to .grad()
Follow ups:
- simplify retains_grad field to not be a vector, since it always holds a single hook
- potentially merge capture hooks with tensor pre hooks, this would involve some additional refactoring since
- python hooks registered to tensor behavior on in-place is still wrong
Pull Request resolved: https://github.com/pytorch/pytorch/pull/85849
Approved by: https://github.com/albanD
