We've root caused this to correctly throwing attribute error on ScriptFunction
when missing attributes are caused. This PR will fix crashes that are showing
up. I'm going to stack a second PR to fix torch._c.ScriptFunction just being a
very badly behaving python object (which should also fix this
Pull Request resolved: https://github.com/pytorch/pytorch/pull/147894
Approved by: https://github.com/jansel
## Context
> **Note:** `mark_traceable` got renamed to `nonstrict_trace` after
> offline discussion. The reasons are (1) it aligns with `torch.export`'s
> `nonstrict` notion, and (2) it's more definitive in behavior suggestion.
1. [Overall Design](https://docs.google.com/document/d/1O-dR2ZQaJQVt_v67AVcDCw2yJLtqgkZFwoXK0buEWRg/edit?tab=t.0)
2. [Dynamo graph representation with `torch._higher_order_ops.flat_apply`](https://docs.google.com/document/d/1YHl5nPTJvYeCPE5TO9uA18DPWNgUYGE4gCn6bFvXcBM/edit?tab=t.0#heading=h.xtw3hhbro4gn)
## Summary
This patch adds a `torch._dynamo.nonstrict_trace` decorator, which
currently is an enhanced version of `torch._dynamo.allow_in_graph` (see
docstring for their differences). Specifically, this patch focuses on
the UI and functionality prototyping/plumbing.
The main enhancement is supporting more input types, and the
implementation challenge lies in reconstructing the input objects from
Dynamo `VariableTracker` (while accounting for buffered side-effects and
guards). This patch takes a middle-ground (simple implementation with a
bit of user labor), by
1. asking the user to provide pytree registration for non-proxy-able
input types,
2. letting Dynamo trace through `pytree_flatten` (which accounts for
buffered side-effects and guards automatically),
3. and passing in the TreeSpec as a graph attribute constant into
`torch._higher_order_ops.flat_apply` (which unflattens the inputs and
invokes the underlying function).
## Next Steps
In subsequent patches, we will try to support the following:
- annotating on class method
- reads to global tensors
- inputs that contains `pytree.register_constant`-ed instances.
- function as input
- more output types (e.g., any pytree-registered type)
- `torch.nn.Module` as inputs
Pull Request resolved: https://github.com/pytorch/pytorch/pull/146367
Approved by: https://github.com/zou3519
ghstack dependencies: #146714
BuiltinVariable.call_hasattr() overrides the base class - but actually behaves differently. The base is `obj.call_hasattr(tx, attr)` but BuiltinVariable's version is `<unused>.call_hasattr(tx, obj, attr)`.
The BuiltinVariable version is used as a pattern from `call_self_handler()` for `BuiltinVariable(hasattr)`. I think the other version is just used for internal `hasattr(obj, name)` so I renamed that one to `call_obj_hasattr`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/145551
Approved by: https://github.com/anijain2305
Fixes#130559
* Intro
This PR adds support for `@contextmanager` in Dynamo. We chose to limit the
scope of this work to only `@contextmanager` and plan to handle generators fully
in #141055 (still in draft).
* Motivation
Dynamo lacks support for generator functions. When it encounters one, it traces
it as if it were a regular function. This is problematic because it can lead to
incorrect behavior. To illustrate, consider the test case below:
```python
import torch
import contextlib
@contextlib.contextmanager
def set_default_dtype(dtype):
old_dtype = torch.get_default_dtype()
try:
torch.set_default_dtype(dtype)
yield
finally:
torch.set_default_dtype(old_dtype)
@torch.compile(backend="eager", fullgraph=True)
def fn():
with set_default_dtype(torch.float64):
x = torch.tensor([3.0, 3.0 + 5.0j])
return x
```
Before this work, Dynamo would not stop at the `yield`, and the graph produced
would contain both calls to `set_default_dtype` executed one after the other.
This is incorrect because the context manager should execute code before and
after the `yield`.
* List of changes
`YIELD_VALUE` now raises an exception (`YieldValueOp`) to signal that control
flow must be suspended and returned to the caller. Additionally, `RETURN_VALUE`
behaves differently in a generator function. Unlike regular functions, where
`RETURN_VALUE` indicates the final result, in generators it signifies that the
generator is exhausted and implicitly raises `StopIteration`.
A new `VariableTracker` named `FunctionDecoratedByContextlibContextManagerVariable`
was introduced to handle `@contextmanager`. This variable tracker acts not just
as a wrapper for the original function but also maintains an internal `tx`
(InstructionTranslator) object to suspend and return control flow to the parent
tracer when a `yield` is encountered.
* Corner cases
Returning a context manager from a compiled function is not supported. This
would require PyTorch to synchronize the generator state between Dynamo and the
interpreter. Any attempt to return it will result in an `IncorrectUsage`
exception.
Graph breaks require special handling as well. In the event of a graph break,
the frame associated with the context manager is skipped, and the context
manager runs in eager mode.
* This PR is breaking my code
There is a configuration flag (`enable_trace_contextlib`) that can be set to
`False` to disable tracing context managers. If this still causes crashes,
please revert this PR.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136033
Approved by: https://github.com/zou3519
**Overview**
This PR moves `torch/distributed/_composable/fsdp` to `torch/distributed/fsdp/_fully_shard` and makes public APIs available from `torch.distributed.fsdp`, e.g.:
```
from torch.distributed.fsdp import fully_shard
```
This is targeting 2.6 release. I rewrote some of the documentation with (hopefully) improved phrasing.
**Changes for Reland**
- Preserved the public objects from `torch/distributed/_composable/fsdp/fully_shard.py` so that the import path still works internally
- Added a unit test that we can do `from torch.distributed._composable.fsdp.fully_shard import FSDPModule`
Differential Revision: [D66890387](https://our.internmc.facebook.com/intern/diff/D66890387)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/141868
Approved by: https://github.com/kwen2501, https://github.com/wconstab, https://github.com/weifengpy, https://github.com/fegin, https://github.com/XilunWu
Co-authored-by: Svetlana Karslioglu <svekars@meta.com>
Previously when Dynamo encounters a `functools.wrap(...)` call, it would
check `VariableTracker.can_reconstruct` and graph break if failed.
That has 2 issues:
1. Implementation of `can_reconstruct` is incorrect, since logic of
reconstructability isn't necessarily encapsulated in
`VariableTracker.reconstruct` -- for some VTs like `CellVariable`,
it's also in `SideEffects.codegen_save_tempvars`. This is exposed by
#134731.
2. We don't always need to reconstruct the result of
`functools.wrap(...)`, for those cases we don't want to give up
tracing by an early `con_reconstruct` check. Instead we could just
let it fall through, and graph break in the actual `reconstruct` call
later, if needed.
This patch removes the `can_reconstruct` check altogether. It was
introduced in #114279, but the added tests pass even without the check
now; this might be because of some recent bug fixing on cells and side
effects.
Fixes#134731, #141514.
D66838708
Pull Request resolved: https://github.com/pytorch/pytorch/pull/142000
Approved by: https://github.com/zou3519
**Overview**
This PR moves `torch/distributed/_composable/fsdp` to `torch/distributed/fsdp/_fully_shard` and makes public APIs available from `torch.distributed.fsdp`, e.g.:
```
from torch.distributed.fsdp import fully_shard
```
This is targeting 2.6 release. I rewrote some of the documentation with (hopefully) improved phrasing.
**Follow-Ups**
- [x] Add some explanation in the docs about FSDP1 vs. FSDP2
- [ ] Move unit tests from `test/distributed/_composable/fsdp` to `test/distributed/fsdp/fully_shard/`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/141868
Approved by: https://github.com/kwen2501, https://github.com/wconstab, https://github.com/weifengpy
Co-authored-by: Svetlana Karslioglu <svekars@meta.com>
Previously when Dynamo encounters a `functools.wrap(...)` call, it would
check `VariableTracker.can_reconstruct` and graph break if failed.
That has 2 issues:
1. Implementation of `can_reconstruct` is incorrect, since logic of
reconstructability isn't necessarily encapsulated in
`VariableTracker.reconstruct` -- for some VTs like `CellVariable`,
it's also in `SideEffects.codegen_save_tempvars`. This is exposed by
#134731.
2. We don't always need to reconstruct the result of
`functools.wrap(...)`, for those cases we don't want to give up
tracing by an early `con_reconstruct` check. Instead we could just
let it fall through, and graph break in the actual `reconstruct` call
later, if needed.
This patch removes the `can_reconstruct` check altogether. It was
introduced in #114279, but the added tests pass even without the check
now; this might be because of some recent bug fixing on cells and side
effects.
Fixes#134731, #141514.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/142000
Approved by: https://github.com/zou3519
Prior to this patch, we are using `ConstantVariable.create` to create VT
for frozenset objects, and intended yet failed to predicate that on all
itmes being literals (see https://github.com/pytorch/pytorch/pull/140984#discussion_r1847393736).
The code was from https://github.com/pytorch/torchdynamo/commit/7c03434 and
the original goal was to help DBR quantization, but as the new test in
this patch shows, it could lead to silent incorrectness.
Upon a closer look, this exposes some subtleties in how Dynamo handles
`ConstantVariable` and `LOAD_CONST`, so this patch both fixes the
aforementioned issue and documents, enforces, and makes explicit the
invariants around `ConstantVariable` and `LOAD_CONST` -- only immutable
objects are supported.
Specifically, this patch:
1. refine the checks for wrapping a `frozenset` object, document why we
can't just wrap its items directly due to lack of `Sourcec` for set
items, and use a safe workaround (`SourcelessBuilder`) to ensure
soundness while keeping the DBR quantization support.
2. Adds more types to `common_constant_types`, thereby making
`ConstantVariable.is_base_literal` more lenient, and strictly checks
this property in the constructor of `ConstantVariable`.
3. Change relevant uses of `create_instruction("LOAD_CONST", ...)` to
`create_load_const` which checks `is_safe_constant`, and makes
developer overrides explicit by using `create_load_const_unchecked`
when needed.
4. In a few places, use more specific `VariableTracker`, e.g.,
`TypingVariable` rather than `ConstantVariable`, and
`FrozensetVariable` rather than `SetVariable`.
(2) and (3) are mainly to future-proof Dynamo against bugs like (1).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/141504
Approved by: https://github.com/jansel
Now that all cells are modeled as `NewCellVariable` in Dynamo, we no
longer need to put cell variables into this special `closure_cells`,
rather we just merge `closure_cells` with `symbolic_locals`.
This allows us to merge and remove some code paths, notably make
`LOAD_CLOSURE` the same as `LOAD_FAST`, and `LOAD_DEREF` & `STORE_DEREF`
the same for inlining or regular `InstructionTranslator`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140154
Approved by: https://github.com/jansel
ghstack dependencies: #140330, #140152, #140436, #140435, #140153
In addition to `NewCellVariable`, Dynamo has 3 ways of modeling cell objects:
1. For cells captured and created by the root frame, represent them as
their contents in `root_tx.symbolic_locals`, which `LOAD_DEREF` and
`STORE_DEREF` update directly, without going through `SideEffects`.
2. `ClosureVariable`: this is created when cells from (1) are captured
by a newly created function Dynamo is about to inline. It's a handle
with a name that redirects `LOAD_DEREF` and `STORE_DEREF` back (1),
to make `root_tx.symbolic_locals` up-to-date.
3. For cells that are captured by both the root frame and some
pre-existing function Dynamo is about to inline, represent those
cells as contents, and do not allow writes to them.
Note that (2) and (3) are mainly to conform with (1) -- to make sure
Dynamo has a consistent modeling of cells for the same cell objects.
In this patch, we represent all of these cells as `NewCellVariable`. The
main new code paths introduced are:
- using `NewCellVariable` to model cell objects created by the root
frame (the cells are passed in as input to `InstructionTranslator`),
this is what allows us to get rid of all 3 legacy paths above.
- adding a new `AutoDerefLocalSource` to deal with the python-code
level (guards) and bytecode level (codegen) auto-dereferencing
behavior, when accessing pre-existing python cells. This also
involves a tiny update to guard manager generation.
- plumbing some extra info into `LocalSource` and `CellVariable` so that
we can still emit `LOAD_DEREF`, `STORE_DEREF`, `LOAD_CLOSURE` (instead
of `make_cell`, `cell_contents` attribute access, and `LOAD_FAST`),
which is important for readability, performance, and some
assumptions `bytecode_transformation.py` makes.
As a result, this patch removes a lot of the now-dead code paths and
TODOs. Notably, it significantly simplified the `prune_dead_locals`
function, which was duplicating a lot of the logic from
`prune_dead_object_new`; this conveniently closes#137123.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140153
Approved by: https://github.com/jansel
ghstack dependencies: #140330, #140152, #140436, #140435
In `match_nested_cell`, Dynamo tried to identify pre-existing captured
cells by `(cell_name, id(cell_contents))`. This works in most cases, but
as the test added in this patch shows, it's not a complete solution.
This patch
1. changes `match_nested_cell` to `lookup_variable_for_captured_cell`,
and does the lookup based on id of cell objects, not their contents.
This requires plumbing a tuple of captured cell objects from
different CPython versions all the way to
`InstructionTranslator.__init__`, where we store a mapping from the
ids of these cell objects, and use it later in
`UserFunctionVariable.bind_args` to look for these unboxed cells.
2. builds off (1) -- rather than using a `VariableTracker` that
represents the content of the unboxed cells, use `ClosureVariable`,
which enables codegen in case these cells escape as closure of a
`NestedUserFunctionVariable`.
The patch adds a regression test for each of the scenarios above:
1. `test_write_to_cells_with_name_shadowing` where Dynamo mistakenly
thought the program is writing to a cell captured by root frame (which
it doesn't support atm), which resulted in
```
File "/Users/ryanguo99/Documents/work/pytorch/torch/_dynamo/symbolic_convert.py", line 3340, in STORE_DEREF
unimplemented("write to __closure__ while inlining")
File "/Users/ryanguo99/Documents/work/pytorch/torch/_dynamo/exc.py", line 313, in unimplemented
raise Unsupported(msg, case_name=case_name)
torch._dynamo.exc.Unsupported: write to __closure__ while inlining
```
2. `test_existing_func_that_creates_capturing_nested_func` where Dynamo
ended up trying to codegen a `NestedUserFunctionVariable` that
captures a cell which was also captured by the root frame, so it was
unboxed and ends up emitting `LOAD_DEREF` rather than
`LOAD_FAST/LOAD_CLOSURE` during codegen, resulting in
```
File "/Users/ryanguo99/Documents/work/pytorch/torch/_dynamo/variables/functions.py", line 105, in _create_nested_fn
func = FunctionType(code, f_globals, name, defaults, closure)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: arg 5 (closure) expected cell, found int
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140436
Approved by: https://github.com/jansel, https://github.com/williamwen42
ghstack dependencies: #140330, #140152
