regionclip-demo / detectron2 /export /torchscript_patch.py
jwyang
first commit
4121bec
# Copyright (c) Facebook, Inc. and its affiliates.
import os
import sys
import tempfile
from contextlib import ExitStack, contextmanager
from copy import deepcopy
from unittest import mock
import torch
from torch import nn
# need some explicit imports due to https://github.com/pytorch/pytorch/issues/38964
import detectron2 # noqa F401
from detectron2.structures import Boxes, Instances
from detectron2.utils.env import _import_file
_counter = 0
def _clear_jit_cache():
from torch.jit._recursive import concrete_type_store
from torch.jit._state import _jit_caching_layer
concrete_type_store.type_store.clear() # for modules
_jit_caching_layer.clear() # for free functions
def _add_instances_conversion_methods(newInstances):
"""
Add from_instances methods to the scripted Instances class.
"""
cls_name = newInstances.__name__
@torch.jit.unused
def from_instances(instances: Instances):
"""
Create scripted Instances from original Instances
"""
fields = instances.get_fields()
image_size = instances.image_size
ret = newInstances(image_size)
for name, val in fields.items():
assert hasattr(ret, f"_{name}"), f"No attribute named {name} in {cls_name}"
setattr(ret, name, deepcopy(val))
return ret
newInstances.from_instances = from_instances
@contextmanager
def patch_instances(fields):
"""
A contextmanager, under which the Instances class in detectron2 is replaced
by a statically-typed scriptable class, defined by `fields`.
See more in `scripting_with_instances`.
"""
with tempfile.TemporaryDirectory(prefix="detectron2") as dir, tempfile.NamedTemporaryFile(
mode="w", encoding="utf-8", suffix=".py", dir=dir, delete=False
) as f:
try:
# Objects that use Instances should not reuse previously-compiled
# results in cache, because `Instances` could be a new class each time.
_clear_jit_cache()
cls_name, s = _gen_instance_module(fields)
f.write(s)
f.flush()
f.close()
module = _import(f.name)
new_instances = getattr(module, cls_name)
_ = torch.jit.script(new_instances)
# let torchscript think Instances was scripted already
Instances.__torch_script_class__ = True
# let torchscript find new_instances when looking for the jit type of Instances
Instances._jit_override_qualname = torch._jit_internal._qualified_name(new_instances)
_add_instances_conversion_methods(new_instances)
yield new_instances
finally:
try:
del Instances.__torch_script_class__
del Instances._jit_override_qualname
except AttributeError:
pass
sys.modules.pop(module.__name__)
def _gen_instance_class(fields):
"""
Args:
fields (dict[name: type])
"""
class _FieldType:
def __init__(self, name, type_):
assert isinstance(name, str), f"Field name must be str, got {name}"
self.name = name
self.type_ = type_
self.annotation = f"{type_.__module__}.{type_.__name__}"
fields = [_FieldType(k, v) for k, v in fields.items()]
def indent(level, s):
return " " * 4 * level + s
lines = []
global _counter
_counter += 1
cls_name = "ScriptedInstances{}".format(_counter)
field_names = tuple(x.name for x in fields)
lines.append(
f"""
class {cls_name}:
def __init__(self, image_size: Tuple[int, int]):
self.image_size = image_size
self._field_names = {field_names}
"""
)
for f in fields:
lines.append(
indent(2, f"self._{f.name} = torch.jit.annotate(Optional[{f.annotation}], None)")
)
for f in fields:
lines.append(
f"""
@property
def {f.name}(self) -> {f.annotation}:
# has to use a local for type refinement
# https://pytorch.org/docs/stable/jit_language_reference.html#optional-type-refinement
t = self._{f.name}
assert t is not None
return t
@{f.name}.setter
def {f.name}(self, value: {f.annotation}) -> None:
self._{f.name} = value
"""
)
# support method `__len__`
lines.append(
"""
def __len__(self) -> int:
"""
)
for f in fields:
lines.append(
f"""
t = self._{f.name}
if t is not None:
return len(t)
"""
)
lines.append(
"""
raise NotImplementedError("Empty Instances does not support __len__!")
"""
)
# support method `has`
lines.append(
"""
def has(self, name: str) -> bool:
"""
)
for f in fields:
lines.append(
f"""
if name == "{f.name}":
return self._{f.name} is not None
"""
)
lines.append(
"""
return False
"""
)
# support method `to`
lines.append(
f"""
def to(self, device: torch.device) -> "{cls_name}":
ret = {cls_name}(self.image_size)
"""
)
for f in fields:
if hasattr(f.type_, "to"):
lines.append(
f"""
t = self._{f.name}
if t is not None:
ret._{f.name} = t.to(device)
"""
)
else:
# For now, ignore fields that cannot be moved to devices.
# Maybe can support other tensor-like classes (e.g. __torch_function__)
pass
lines.append(
"""
return ret
"""
)
# support method `getitem`
lines.append(
f"""
def __getitem__(self, item) -> "{cls_name}":
ret = {cls_name}(self.image_size)
"""
)
for f in fields:
lines.append(
f"""
t = self._{f.name}
if t is not None:
ret._{f.name} = t[item]
"""
)
lines.append(
"""
return ret
"""
)
# support method `get_fields()`
lines.append(
"""
def get_fields(self) -> Dict[str, Tensor]:
ret = {}
"""
)
for f in fields:
if f.type_ == Boxes:
stmt = "t.tensor"
elif f.type_ == torch.Tensor:
stmt = "t"
else:
stmt = f'assert False, "unsupported type {str(f.type_)}"'
lines.append(
f"""
t = self._{f.name}
if t is not None:
ret["{f.name}"] = {stmt}
"""
)
lines.append(
"""
return ret"""
)
return cls_name, os.linesep.join(lines)
def _gen_instance_module(fields):
# TODO: find a more automatic way to enable import of other classes
s = """
from copy import deepcopy
import torch
from torch import Tensor
import typing
from typing import *
import detectron2
from detectron2.structures import Boxes, Instances
"""
cls_name, cls_def = _gen_instance_class(fields)
s += cls_def
return cls_name, s
def _import(path):
return _import_file(
"{}{}".format(sys.modules[__name__].__name__, _counter), path, make_importable=True
)
@contextmanager
def patch_builtin_len(modules=()):
"""
Patch the builtin len() function of a few detectron2 modules
to use __len__ instead, because __len__ does not convert values to
integers and therefore is friendly to tracing.
Args:
modules (list[stsr]): names of extra modules to patch len(), in
addition to those in detectron2.
"""
def _new_len(obj):
return obj.__len__()
with ExitStack() as stack:
MODULES = [
"detectron2.modeling.roi_heads.fast_rcnn",
"detectron2.modeling.roi_heads.mask_head",
"detectron2.modeling.roi_heads.keypoint_head",
] + list(modules)
ctxs = [stack.enter_context(mock.patch(mod + ".len")) for mod in MODULES]
for m in ctxs:
m.side_effect = _new_len
yield
def patch_nonscriptable_classes():
"""
Apply patches on a few nonscriptable detectron2 classes.
Should not have side-effects on eager usage.
"""
# __prepare_scriptable__ can also be added to models for easier maintenance.
# But it complicates the clean model code.
from detectron2.modeling.backbone import ResNet, FPN
# Due to https://github.com/pytorch/pytorch/issues/36061,
# we change backbone to use ModuleList for scripting.
# (note: this changes param names in state_dict)
def prepare_resnet(self):
ret = deepcopy(self)
ret.stages = nn.ModuleList(ret.stages)
for k in self.stage_names:
delattr(ret, k)
return ret
ResNet.__prepare_scriptable__ = prepare_resnet
def prepare_fpn(self):
ret = deepcopy(self)
ret.lateral_convs = nn.ModuleList(ret.lateral_convs)
ret.output_convs = nn.ModuleList(ret.output_convs)
for name, _ in self.named_children():
if name.startswith("fpn_"):
delattr(ret, name)
return ret
FPN.__prepare_scriptable__ = prepare_fpn
# Annotate some attributes to be constants for the purpose of scripting,
# even though they are not constants in eager mode.
from detectron2.modeling.roi_heads import StandardROIHeads
if hasattr(StandardROIHeads, "__annotations__"):
# copy first to avoid editing annotations of base class
StandardROIHeads.__annotations__ = deepcopy(StandardROIHeads.__annotations__)
StandardROIHeads.__annotations__["mask_on"] = torch.jit.Final[bool]
StandardROIHeads.__annotations__["keypoint_on"] = torch.jit.Final[bool]
# These patches are not supposed to have side-effects.
patch_nonscriptable_classes()
@contextmanager
def freeze_training_mode(model):
"""
A context manager that annotates the "training" attribute of every submodule
to constant, so that the training codepath in these modules can be
meta-compiled away. Upon exiting, the annotations are reverted.
"""
classes = {type(x) for x in model.modules()}
# __constants__ is the old way to annotate constants and not compatible
# with __annotations__ .
classes = {x for x in classes if not hasattr(x, "__constants__")}
for cls in classes:
cls.__annotations__["training"] = torch.jit.Final[bool]
yield
for cls in classes:
cls.__annotations__["training"] = bool