Files
pytorch/torch/_dynamo/codegen.py
Michael Lazos fbeca60b1f Remove replace_all and make VTs mutable (#113725)
1.  Removes calls to `replace_all` and `clone` and makes VTs mutable.
2. Properly handles Tuple Iterator mutation. Previously TupleIterator variables would only be properly reconstructed if they were advanced at least once in a frame. On calls to `next`, the source information would be lost (due to constructing a new iterator without using builder), which would ensure that during codegen the variable would be reconstructed from scratch. Now that VTs are mutated, the source is never lost, so we need to properly track mutation and handle it by replaying calls to `next` at the end of the modified bytecode.
3. Added test for checking iadd side effects, this was missing in our unit test coverage.
4. Fixed two incorrect sources, DelayGraphBreakVariable, and UserMethodVariable both relied on setting the source to AttrSource(parent, name) at the callsite of `var_getattr`.
5. Fixed a bug in inplace adding for lists, it would set the resulting VariableTracker's source to `None` which would utilize a different reconstruct path in codegen. Now this is handled explicitly by reconstructing vars when allow_cache=`False`, so that during side effect replay, the mutated var is correctly updated.

In subsequent PRs:
* Refactoring side effect tracking to be significantly simpler (I think we only need an `is_modified` flag)
* Refactor `next_variables` iterator to match the signature of `next`
* Remove all references to `options` in the code
* Refactor VTs representing mutable collections to implement their own mutation update handling
* Remove clone and/or make it specific to lists for creating slices
* Add mutation tracking/replay for sets
* Add mutation tracking/replay for iter.py
* Removing setting source in builder (it's set at the top level after a var is returned)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/113725
Approved by: https://github.com/jansel
2023-12-10 09:31:21 +00:00

369 lines
14 KiB
Python

import collections
import dataclasses
import re
import sys
import types
from typing import Counter, Dict, List, Optional
import torch.nn
from . import utils
from .bytecode_transformation import (
create_call_function,
create_dup_top,
create_instruction,
create_load_global,
create_rot_n,
Instruction,
)
from .exc import unimplemented
from .source import AttrSource, Source
from .utils import is_safe_constant, rot_n_helper
from .variables.base import VariableTracker
from .variables.nn_module import NNModuleVariable
from .variables.tensor import (
NumpyNdarrayVariable,
SymNodeVariable,
TensorVariable,
UnspecializedPythonVariable,
)
from .variables.torch_function import TensorWithTFOverrideVariable
@dataclasses.dataclass
class GraphOutputEntry:
index: int
variable: VariableTracker
class PyCodegen:
"""
Helper class uses for constructing Python bytecode
"""
def __init__(
self,
tx=None,
root: Optional[torch.nn.Module] = None,
graph_output_var: Optional[str] = None,
tempvars=None,
):
self.root = root
self.top_of_stack: Optional[VariableTracker] = None
self.uses: Counter[VariableTracker] = collections.Counter()
self.graph_outputs: Dict[int, GraphOutputEntry] = {}
self._output: List[Instruction] = []
self.tempvars = tempvars or {}
self.tx = tx
self.graph_output_var = graph_output_var
self.code_options = self.tx.output.code_options
self.cell_and_freevars = self.tx.cell_and_freevars
self.new_var = self.tx.output.new_var
self.mutable_side_effects_from_source = False
def restore_stack(self, stack_values):
prior = self.mutable_side_effects_from_source
self.mutable_side_effects_from_source = True
try:
self.foreach(stack_values)
finally:
self.mutable_side_effects_from_source = prior
def graph_output_vars(self):
return [x.variable for x in self.graph_outputs.values()]
def __call__(self, value, allow_cache=True):
"""Generate code such that top-of-stack (TOS) is set to value"""
if isinstance(value, Source):
self._output.extend(value.reconstruct(self))
self.clear_tos()
return
assert isinstance(value, VariableTracker)
output = self._output
graph_outputs = self.graph_outputs
if self.top_of_stack is value and allow_cache:
output.append(create_dup_top())
return
if self.mutable_side_effects_from_source:
# this is needed to get aliasing relationships right
# value.mutable_local.source will get mutated to hold `value`
# mutable_side_effects_from_source=False is used to codegen the mutation
# mutable_side_effects_from_source=True is used to codegen a reference
from .side_effects import MutableSideEffects
if isinstance(value.mutable_local, MutableSideEffects):
self(value.mutable_local.source)
return
if allow_cache:
if value.mutable_local and value.mutable_local in self.tempvars:
output.append(self.create_load(self.tempvars[value.mutable_local]))
self.top_of_stack = value
return
if self.tempvars.get(value) is not None:
output.append(self.create_load(self.tempvars[value]))
self.top_of_stack = value
return
if value.source is not None and allow_cache:
output.extend(value.source.reconstruct(self))
elif value.is_python_constant() and is_safe_constant(
value.as_python_constant()
):
output.append(self.create_load_const(value.as_python_constant()))
elif isinstance(value, TensorWithTFOverrideVariable):
graph_outputs_key = self.add_graph_output(value)
output.append(
self.create_load_global(
value.global_mangled_class_name(), True, add=True
)
)
self.load_graph_output(graph_outputs[graph_outputs_key].index)
output.extend(create_call_function(1, True))
elif isinstance(
value,
(
TensorVariable,
SymNodeVariable,
UnspecializedPythonVariable,
NumpyNdarrayVariable,
),
):
graph_outputs_key = self.add_graph_output(value)
if isinstance(value, NumpyNdarrayVariable):
self.load_import_from(utils.__name__, "to_numpy_helper")
self.load_graph_output(graph_outputs[graph_outputs_key].index)
if isinstance(value, NumpyNdarrayVariable):
output.extend(create_call_function(1, True))
elif isinstance(value, UnspecializedPythonVariable) and value.need_unwrap:
output.extend(
[self.create_load_attr("item")] + create_call_function(0, True)
)
elif isinstance(value, NNModuleVariable):
parts = value.module_key.split(".")
if parts[0] in self.code_options["co_varnames"]:
output.append(self.create_load(parts[0]))
parts = parts[1:]
else:
assert self.root is not None
output.append(self.create_load_output(self.root))
for part in parts:
output.append(self.create_load_attr(part))
else:
self.uses[value] += 1
try:
output.extend(value.reconstruct(self))
except NotImplementedError:
unimplemented(f"reconstruct: {value}")
if allow_cache and value in self.tempvars:
self._output.append(create_dup_top())
self.add_cache(value)
self.top_of_stack = value
def add_graph_output(self, value):
graph_outputs_key = id(value.as_proxy())
if graph_outputs_key not in self.graph_outputs:
self.graph_outputs[graph_outputs_key] = GraphOutputEntry(
len(self.graph_outputs), value
)
return graph_outputs_key
def load_graph_output(self, index):
output = self._output
output.append(self.create_load(self.graph_output_var))
output.append(self._create_load_const(index))
output.append(create_instruction("BINARY_SUBSCR"))
def add_cache(self, value):
var = self.new_var()
self.tempvars[value] = var
if value.mutable_local:
self.tempvars[value.mutable_local] = var
self._output.append(self.create_store(var))
def foreach(self, items):
for i in items:
self(i)
def setup_globally_cached(self, name, value, push_null):
"""Store value in a new global"""
name = re.sub(r"[^a-zA-Z0-9_]+", "_", name)
f_globals = self.tx.f_globals
if name in f_globals:
assert id(f_globals[name]) == id(value)
else:
f_globals[name] = value
return [self.create_load_global(name, push_null, add=True)]
def clear_tos(self):
self.top_of_stack = None
def append_output(self, inst):
assert isinstance(inst, Instruction)
self._output.append(inst)
self.clear_tos()
def extend_output(self, insts):
assert all(isinstance(x, Instruction) for x in insts)
self._output.extend(insts)
self.clear_tos()
def get_instructions(self) -> List[Instruction]:
return self._output
def create_load(self, name) -> Instruction:
if name in self.cell_and_freevars():
return create_instruction("LOAD_DEREF", argval=name)
assert name in self.code_options["co_varnames"], f"{name} missing"
return create_instruction("LOAD_FAST", argval=name)
def create_load_closure(self, name) -> Instruction:
assert name in self.cell_and_freevars()
return create_instruction("LOAD_CLOSURE", argval=name)
def create_store(self, name) -> Instruction:
if name in self.cell_and_freevars():
return create_instruction("STORE_DEREF", argval=name)
assert name in self.code_options["co_varnames"]
return create_instruction("STORE_FAST", argval=name)
def create_load_global(self, name, push_null, add=False):
if add:
self.tx.output.update_co_names(name)
assert name in self.code_options["co_names"], f"{name} not in co_names"
return create_load_global(name, push_null)
def create_load_const(self, value) -> Instruction:
assert is_safe_constant(value), f"unsafe constant {value}"
return self._create_load_const(value)
def _create_load_const(self, value) -> Instruction:
return create_instruction("LOAD_CONST", argval=value)
create_load_output = _create_load_const
def create_load_attr(self, name) -> Instruction:
if name not in self.code_options["co_names"]:
self.code_options["co_names"] += (name,)
return create_instruction("LOAD_ATTR", argval=name)
def create_load_attrs(self, names):
return [self.create_load_attr(name) for name in names.split(".")]
def load_function_name(self, fn_name, push_null, num_on_stack=0):
"""Load the global fn_name on the stack num_on_stack down"""
output = []
if push_null and sys.version_info >= (3, 11):
output.extend(
[create_instruction("PUSH_NULL"), *self.rot_n(num_on_stack + 1)]
)
output.extend(
[
self.create_load_global(fn_name, False, add=True),
*self.rot_n(num_on_stack + 1),
]
)
return output
def rot_n(self, n):
try:
return create_rot_n(n)
except AttributeError:
# desired rotate bytecode doesn't exist, generate equivalent bytecode
return [
create_instruction("BUILD_TUPLE", arg=n),
self._create_load_const(rot_n_helper(n)),
*create_rot_n(2),
create_instruction("CALL_FUNCTION_EX", arg=0),
create_instruction("UNPACK_SEQUENCE", arg=n),
]
def pop_null(self):
# POP_TOP doesn't work for null, so we pop nulls by pushing in a
# nop function, calling it (which consumes the null), and popping the result.
assert sys.version_info >= (3, 11)
return [
self._create_load_const(lambda: None),
*create_call_function(0, False),
create_instruction("POP_TOP"),
]
def make_function_with_closure(
self, fn_name: str, code: types.CodeType, push_null: bool, num_on_stack=0
):
freevars = code.co_freevars
assert freevars
output = self._output
if sys.version_info >= (3, 11) and push_null:
output.append(create_instruction("PUSH_NULL"))
output.extend(self.rot_n(num_on_stack + 1))
for var in freevars:
assert var in self.cell_and_freevars()
output.append(create_instruction("LOAD_CLOSURE", argval=var))
output.append(create_instruction("BUILD_TUPLE", arg=len(freevars)))
output.append(self.create_load_const(code))
if sys.version_info < (3, 11):
output.append(self.create_load_const(fn_name))
output.append(create_instruction("MAKE_FUNCTION", arg=0x08))
output.extend(self.rot_n(num_on_stack + 1))
self.clear_tos()
def create_load_python_module(self, mod, push_null):
"""
Generate a LOAD_GLOBAL instruction to fetch a given python module.
"""
global_scope = self.tx.output.global_scope
name = re.sub(r"^.*[.]", "", mod.__name__)
if global_scope.get(name, None) is mod:
return self.create_load_global(name, push_null, add=True)
mangled_name = f"___module_{name}_{id(mod)}"
if mangled_name not in global_scope:
self.tx.output.install_global(mangled_name, mod)
return self.create_load_global(mangled_name, push_null, add=True)
def make_call_generated_code(self, fn_name: str) -> None:
"""Call the generated code function stored in fn_name"""
self.extend_output(self.load_function_name(fn_name, True))
graphargs = self.tx.output.graphargs
for arg in graphargs:
if arg.is_unspecialized:
self.extend_output(
[
self.create_load_python_module(torch, True),
self.create_load_attr("as_tensor"),
]
)
self.extend_output(arg.load(self))
self.extend_output(create_call_function(1, False))
else:
self.extend_output(arg.load(self))
self.extend_output(create_call_function(len(graphargs), False))
def load_import_from(self, module_name, object_name) -> None:
self.extend_output(
AttrSource(self.tx.import_source(module_name), object_name).reconstruct(
self
)
)
def create_call_function_kw(self, nargs, kw_names, push_null) -> List[Instruction]:
if sys.version_info >= (3, 11):
output = create_call_function(nargs, push_null)
assert output[-2].opname == "PRECALL"
kw_names_inst = create_instruction("KW_NAMES", argval=kw_names)
output.insert(-2, kw_names_inst)
return output
return [
self.create_load_const(kw_names),
create_instruction("CALL_FUNCTION_KW", arg=nargs),
]