team-10/venv/Lib/site-packages/torch/_subclasses/fake_utils.py
2025-08-02 02:00:33 +02:00

304 lines
10 KiB
Python

# mypy: ignore-errors
import functools
import warnings
from typing import Any, Callable, Union
import torch
import torch.utils._pytree as pytree
from torch._ops import OpOverload
from torch._subclasses.fake_tensor import (
FakeTensor,
FakeTensorMode,
MetadataMismatchError,
tree_flatten_only,
UnsupportedFakeTensorException,
)
from torch.utils._python_dispatch import TorchDispatchMode
aten = torch._ops.ops.aten
def outputs_alias_inputs(outputs, inputs):
input_storages = {
inp._typed_storage()._cdata
for inp in tree_flatten_only(torch.Tensor, inputs)
if torch._C._has_storage(inp)
}
return any(
torch._C._has_storage(out) and out._typed_storage()._cdata in input_storages
for out in tree_flatten_only(torch.Tensor, outputs)
)
def outputs_are_inputs(outputs, inputs):
input_ids = {id(inp) for inp in tree_flatten_only(torch.Tensor, inputs)}
return any(id(out) in input_ids for out in tree_flatten_only(torch.Tensor, outputs))
def output_alias_each_other(outputs):
storages = set()
for out in tree_flatten_only(torch.Tensor, outputs):
if not torch._C._has_storage(out):
continue
stor = out._typed_storage()._cdata
if stor in storages:
return True
storages.add(stor)
return False
def _check_alias_info(context, real_out, real_in, fake_out, fake_in):
r_aliasing = outputs_alias_inputs(real_out, real_in)
f_aliasing = outputs_alias_inputs(fake_out, fake_in)
if r_aliasing != f_aliasing:
raise MetadataMismatchError(
f"{context} mismatch in outputs_alias_inputs check {f_aliasing} != {r_aliasing}"
)
r_identity_eq = outputs_are_inputs(real_out, real_in)
f_identity_eq = outputs_are_inputs(fake_out, fake_in)
if r_identity_eq != f_identity_eq:
raise MetadataMismatchError(
f"{context} mismatch in outputs_are_inputs check {f_identity_eq} != {r_identity_eq}"
)
r_output_alias_each_other = output_alias_each_other(real_out)
f_output_alias_each_other = output_alias_each_other(fake_out)
if r_output_alias_each_other != f_output_alias_each_other:
raise MetadataMismatchError(
f"{context} mismatch in outputs_alias_each_other check "
f"{f_output_alias_each_other} != {r_output_alias_each_other}"
)
def is_sdpa_error(func, idx, e):
if (
(
func is aten._scaled_dot_product_flash_attention.default
or func is aten._flash_attention_forward.default
)
and idx in (6, 7)
and "Devices" in repr(e)
):
return True
if (
(
func is aten._scaled_dot_product_efficient_attention.default
or func is aten._efficient_attention_forward.default
)
and idx in (2, 3)
and "Devices" in repr(e)
):
return True
if (
func is aten._scaled_dot_product_cudnn_attention.default
and idx in (6, 7)
and "Devices" in repr(e)
):
return True
return False
def try_convert_fake_to_real(
ten_list: list[Union[FakeTensor, Any]]
) -> list[Union[FakeTensor, torch.Tensor, Any]]:
"""
Attempt to convert fake tensors to a corresponding real tensor with the correct underlying storage by looking up
the FakeTensorMode meta to real storage mapping. On failure to find the storage mapping, the FakeTensor will
remain in the list.
Note: this is not currently optimized (makes copies of the meta converter internal dictionaries)
"""
fake_tensor = next(
(item for item in ten_list if isinstance(item, FakeTensor)), None
)
if fake_tensor is None:
return ten_list
fake_mode = fake_tensor.fake_mode
meta_converter = fake_mode.fake_tensor_converter.meta_converter
desc = meta_converter.describer
storage_to_key = {v: k for k, v in meta_converter.storage_memo.items()}
key_to_real_storage = {v: k for k, v in desc.lookup_storage.items()}
out = []
for t in ten_list:
if not isinstance(t, FakeTensor) or not t.layout == torch.strided:
out.append(t)
continue
key = storage_to_key.get(t.untyped_storage())
real_storage = None if key is None else key_to_real_storage.get(key)
if real_storage is None:
out.append(t)
continue
unhinted = False
def map_symint(s):
nonlocal unhinted
if not isinstance(s, torch.SymInt):
return s
unhinted = unhinted if not unhinted else s.node.has_hint()
return s.node.hint
stor_offset = map_symint(t.storage_offset())
size = [map_symint(s) for s in t.shape]
stride = [map_symint(s) for s in t.stride()]
if unhinted:
out.append(t)
continue
new_tensor = torch.empty(
[],
dtype=t.dtype,
device=t.device,
)
new_tensor.set_(
real_storage,
storage_offset=stor_offset,
size=size,
stride=stride,
)
out.append(new_tensor.clone())
return out
def _check_fake_real_tensors(
real_out: torch.Tensor,
fake_out: FakeTensor,
context="",
sizes=True,
strides=False,
storage_offset=True,
requires_grad=True,
):
if requires_grad:
if real_out.requires_grad != fake_out.requires_grad:
raise MetadataMismatchError(
f"{context} mismatched requires_grad-ness of outputs. "
f"This usually means that you have added autograd support "
f"for your operator at a dispatch key other than Autograd, "
f"which will lead to problems"
)
if torch._C._has_storage(real_out):
r_offset = real_out.storage_offset()
f_offset = fake_out.storage_offset()
if r_offset != f_offset:
raise MetadataMismatchError(f"{context} mismatched storage offset")
torch._prims.utils.compare_tensor_meta(
real_out,
fake_out,
check_sizes=sizes,
check_strides=strides,
allow_rhs_unbacked=True,
)
class CrossRefFakeMode(TorchDispatchMode):
def __init__(
self,
ignore_op_fn: Union[Callable[[OpOverload], bool], None] = None,
*,
check_strides=True,
check_aliasing=True,
only_check_ops_with_meta=True,
):
super().__init__()
self.ignore_op_fn = (
ignore_op_fn if ignore_op_fn is not None else lambda fn: False
)
self.check_strides = check_strides
self.check_aliasing = check_aliasing
self.only_check_ops_with_meta = only_check_ops_with_meta
def __torch_dispatch__(self, func, types, args=(), kwargs=None):
kwargs = kwargs or {}
fake_r = None
# empty_like excluded for now due to sparse complex
# aten._to_dense.default this one is getting called with csc
if (
func
not in (
aten.lift_fresh.default,
aten.lift_fresh_copy.default,
aten.set_.source_Storage_storage_offset,
)
and not self.ignore_op_fn(func)
and (
not self.only_check_ops_with_meta
or torch._subclasses.fake_impls.has_meta(func)
)
and torch.Tag.dynamic_output_shape not in func.tags
and torch.Tag.inplace_view not in func.tags
and torch.Tag.data_dependent_output not in func.tags
):
# Do not import symbolic_shapes at the top of the module as it imports sympy and that's slow
from torch.fx.experimental.symbolic_shapes import ShapeEnv
try:
# TODO: enable_python_dispatcher() here
with FakeTensorMode(shape_env=ShapeEnv()) as fake_mode:
fake_args, fake_kwargs = pytree.tree_map_only(
torch.Tensor,
functools.partial(fake_mode.from_tensor, static_shapes=True),
(args, kwargs),
)
with warnings.catch_warnings():
fake_r = func(*fake_args, **fake_kwargs)
except UnsupportedFakeTensorException:
pass
context = (
f"When comparing the output of {func} on FakeTensor and concrete Tensors, "
f"found"
)
r = func(*args, **kwargs)
if fake_r is not None:
r_flat = pytree.tree_leaves(r)
f_flat = pytree.tree_leaves(fake_r)
assert len(f_flat) == len(
r_flat
), f"{context} mismatch in number of returns {len(f_flat)} != {len(r_flat)}"
if self.check_aliasing:
_check_alias_info(
context, r, (args, kwargs), fake_r, (fake_args, fake_kwargs)
)
for idx, (r_out, f_out) in enumerate(
zip(pytree.tree_leaves(r), pytree.tree_leaves(fake_r))
):
r_is_ten = isinstance(r_out, torch.Tensor)
assert r_is_ten == isinstance(
f_out, torch.Tensor
), f"{context} mismatched number of tensor outputs"
if r_is_ten:
try:
_check_fake_real_tensors(
r_out,
f_out,
sizes=True,
strides=self.check_strides,
storage_offset=True,
requires_grad=True,
)
except Exception as e:
if is_sdpa_error(func, idx, e):
continue
error_message = (
f"{context} mismatched tensor metadata: {e}"
if len(r_flat) == 1
else f"{context} mismatched tensor metadata for output[{idx}]: {e}"
)
raise MetadataMismatchError(error_message) from e
return r