pytorch/torch/jit/frontend.py
Wanchao Liang 47c1badf90 Fix the clamp special case and gradient problem on None, add None to JIT (#9596)
Summary:
Supersedes #8925

This PR fixes #8502, it fixes the gradients problem for clamp when passing None to the function, and add support for the NoneLiteral and NoneType in script to enable clamp tests. Now we could have corner cases like:

```python
torch.jit.script
def func():
    x = torch.randn(3, 3, requires_grad=True)
    y = torch.clamp(x, None, 0) # max = 0
    y = torch.clamp(x, min=None, max=0)
```

In both JIT and Aten, we use Scalar(NAN) as a sentinel value when passing None type to function clamp, this is the current way we used to support None type in JIT and to solve the gradient problem when user explicitly passing None into clamp.

In JIT side, we create a tensor(NAN) and undefinedTensor if we encounter None when matching the function schema, and later in the interpreter, it will translate to Scalar(NAN) if needed.

Ideally we don't need clamp_min and clamp_max in ATenNative/Autograd and could only support clamp after this change, but since bunch of other operators (e.g. Activation.cpp, Loss.cpp) is using clamp_min in several places, we will still have the functions available, but all python invocations will only call clamp instead of clamp_min/max (with calling underlying th_max/th_min in clamp).

zdevito jamesr66a
Pull Request resolved: https://github.com/pytorch/pytorch/pull/9596

Reviewed By: zdevito

Differential Revision: D8940839

Pulled By: wanchaol

fbshipit-source-id: c543a867b82e0ab8c99384773b173fdde2605d28
2018-07-27 22:54:33 -07:00

464 lines
16 KiB
Python

import torch
import sys
import ast
import inspect
import string
from textwrap import dedent
from functools import partial
from collections import namedtuple
from torch._C._jit_tree_views import *
PY2 = sys.version_info[0] == 2
_reserved_prefix = '__jit'
_reserved_names = {'print'}
_identifier_chars = set(string.ascii_lowercase + string.ascii_uppercase + string.digits)
def is_reserved_name(name):
return name.startswith(_reserved_prefix) or name in _reserved_names
pretty_node_names = {
ast.FunctionDef: "function definitions",
ast.For: "for loops",
ast.Delete: "del statements",
ast.ClassDef: "class definitions",
ast.With: "with statements",
ast.Raise: "raise statements",
ast.Assert: "assertions",
ast.Import: "import statements",
ast.ImportFrom: "import statements",
ast.Global: "global variables",
ast.Break: "break statements",
ast.Continue: "continue statements",
}
node_start_tokens = {
ast.FunctionDef: "def",
ast.For: "for",
ast.Delete: "del",
ast.ClassDef: "class",
ast.With: "with",
ast.Raise: "raise",
ast.Assert: "assert",
ast.Import: "import",
ast.ImportFrom: "from",
ast.Global: "global",
ast.Break: "break",
ast.Continue: "continue",
}
if PY2:
pretty_node_names.update({
ast.Print: "print statements",
ast.TryExcept: "try blocks",
ast.TryFinally: "try blocks",
ast.Exec: "exec statements",
})
node_start_tokens.update({
ast.Print: "print",
ast.TryExcept: "try",
ast.TryFinally: "try",
ast.Exec: "exec",
})
else:
pretty_node_names.update({
ast.AsyncFunctionDef: "async function definitions",
ast.AsyncFor: "async for loops",
ast.AsyncWith: "async with statements",
ast.Try: "try blocks",
ast.Nonlocal: "nonlocal variables",
})
node_start_tokens.update({
ast.AsyncFunctionDef: "async def",
ast.AsyncFor: "async for",
ast.AsyncWith: "async with",
ast.Try: "try",
ast.Nonlocal: "nonlocal",
})
if sys.version_info >= (3, 6):
pretty_node_names.update({
ast.AnnAssign: "annotated assignments",
})
# NB: no specific token for AnnAssign
class FrontendError(Exception):
def __init__(self, source_range, msg):
self.source_range = source_range
self.msg = msg
def __str__(self):
result = self.msg
if self.source_range is not None:
result += '\n' + self.source_range.highlight()
return result
class NotSupportedError(FrontendError):
pass
class UnsupportedNodeError(NotSupportedError):
def __init__(self, ctx, offending_node):
# If we don't have a specific token, we default to length of 1
node_type = type(offending_node)
range_len = len(node_start_tokens.get(node_type, ' '))
source_range = ctx.make_range(offending_node.lineno,
offending_node.col_offset,
offending_node.col_offset + range_len)
feature_name = pretty_node_names.get(node_type, node_type.__name__)
msg = "{} aren't supported".format(feature_name)
super(NotSupportedError, self).__init__(source_range, msg)
class FrontendTypeError(FrontendError):
pass
def build_stmts(ctx, stmts):
stmts = [build_stmt(ctx, s) for s in stmts]
return list(filter(None, stmts))
def get_jit_ast(fn):
source = dedent(inspect.getsource(fn))
py_ast = ast.parse(source)
if len(py_ast.body) != 1 or not isinstance(py_ast.body[0], ast.FunctionDef):
raise RuntimeError("expected a single top-level function")
return build_def(SourceRangeFactory(source), py_ast.body[0])
class Builder(object):
def __call__(self, ctx, node):
method = getattr(self, 'build_' + node.__class__.__name__, None)
if method is None:
raise UnsupportedNodeError(ctx, node)
return method(ctx, node)
def build_def(ctx, py_def):
returns = []
ret_body = []
body = py_def.body
r = ctx.make_range(py_def.lineno, py_def.col_offset,
py_def.col_offset + len("def"))
return Def(Ident(r, py_def.name),
build_param_list(ctx, py_def.args),
build_stmts(ctx, body))
_vararg_kwarg_err = ("Compiled functions can't take variable number of arguments, "
"have default values for arguments, nor keyword-only arguments")
def build_param_list(ctx, py_args):
if py_args.vararg is not None or py_args.kwarg is not None or py_args.defaults:
raise ValueError(_vararg_kwarg_err)
if not PY2 and (py_args.kw_defaults or py_args.kwonlyargs):
raise ValueError(_vararg_kwarg_err)
return [build_param(ctx, arg) for arg in py_args.args]
def build_param(ctx, py_arg):
# NB: In Python3 py_arg is a pair of (str arg, expr? annotation)
# In Python2 py_arg is a Name (Expr subclass)
if getattr(py_arg, 'annotation', None) is not None:
raise ValueError("Compiled functions don't support annotations")
name = py_arg.id if PY2 else py_arg.arg
r = ctx.make_range(py_arg.lineno, py_arg.col_offset, py_arg.col_offset + len(name))
return Param(TensorType(r), Ident(r, name))
class StmtBuilder(Builder):
augassign_map = {
ast.Add: '+',
ast.Sub: '-',
ast.Mult: '*',
ast.Div: '/',
}
@staticmethod
def build_Expr(ctx, stmt):
value = stmt.value
if value.__class__.__name__ == 'Str':
# If a statement is a string literal expression,
# then it is a docstring. Just ignore it.
return None
else:
return ExprStmt([build_expr(ctx, value)])
@staticmethod
def get_assign_lhs_expr(ctx, expr):
var = build_expr(ctx, expr)
if not isinstance(var, Var) and not isinstance(var, Starred):
raise NotSupportedError(var.range(),
"the only expressions allowed on the left hand side of "
"assignments are variable names and starred expressions")
return var
@staticmethod
def build_Assign(ctx, stmt):
rhs = build_expr(ctx, stmt.value)
if len(stmt.targets) > 1:
start_point = ctx.make_range(stmt.lineno, stmt.col_offset, stmt.col_offset + 1)
raise NotSupportedError(ctx.make_raw_range(start_point.start, rhs.range().end),
"Performing multiple assignments in a single line isn't supported")
py_lhs = stmt.targets[0]
py_lhs_exprs = py_lhs.elts if isinstance(py_lhs, ast.Tuple) else [py_lhs]
return Assign([StmtBuilder.get_assign_lhs_expr(ctx, e) for e in py_lhs_exprs], '=', rhs)
@staticmethod
def build_Return(ctx, stmt):
r = ctx.make_range(stmt.lineno, stmt.col_offset, stmt.col_offset + len("return"))
values = (stmt.value,) if not isinstance(stmt.value, ast.Tuple) else stmt.value.elts
return Return(r, [build_expr(ctx, val) for val in values if val is not None])
@staticmethod
def build_AugAssign(ctx, stmt):
lhs = [StmtBuilder.get_assign_lhs_expr(ctx, stmt.target)]
rhs = build_expr(ctx, stmt.value)
op = type(stmt.op)
if op in StmtBuilder.augassign_map:
op_token = StmtBuilder.augassign_map[op]
else:
raise NotSupportedError(
find_before(ctx, rhs.range().start, '=', offsets=(-1, 0)),
"unsupported kind of augumented assignment: " + op.__name__)
return Assign(lhs, op_token, rhs)
@staticmethod
def build_While(ctx, stmt):
if stmt.orelse:
# TODO: try to recover the location of else:? Python doesn't give us useful
# annotations in this case
raise NotSupportedError(None, "else branches of while loops aren't supported")
r = ctx.make_range(stmt.lineno, stmt.col_offset, stmt.col_offset + len("while"))
return While(r, build_expr(ctx, stmt.test),
build_stmts(ctx, stmt.body))
@staticmethod
def build_For(ctx, stmt):
r = ctx.make_range(stmt.lineno, stmt.col_offset, stmt.col_offset + len("for"))
return For(
r, [StmtBuilder.get_assign_lhs_expr(ctx, stmt.target)],
[build_expr(ctx, stmt.iter)], build_stmts(ctx, stmt.body))
@staticmethod
def build_If(ctx, stmt):
r = ctx.make_range(stmt.lineno, stmt.col_offset, stmt.col_offset + len("if"))
return If(r, build_expr(ctx, stmt.test),
build_stmts(ctx, stmt.body),
build_stmts(ctx, stmt.orelse))
@staticmethod
def build_Print(ctx, stmt):
r = ctx.make_range(stmt.lineno, stmt.col_offset, stmt.col_offset + len("print"))
if stmt.dest:
raise NotSupportedError(r, "print statements with non-default destinations aren't supported")
args = [build_expr(ctx, val) for val in stmt.values]
return ExprStmt([Apply(Var(Ident(r, "print")), args, [])])
class ExprBuilder(Builder):
binop_map = {
ast.Add: '+',
ast.Sub: '-',
ast.Mult: '*',
ast.Div: '/',
ast.Pow: '**',
}
if not PY2:
binop_map[ast.MatMult] = '@'
unop_map = {
ast.Not: 'not',
ast.USub: '-',
}
boolop_map = {
ast.And: 'and',
ast.Or: 'or',
}
cmpop_map = {
ast.Eq: '==',
ast.NotEq: '!=',
ast.LtE: '<=',
ast.Lt: '<',
ast.GtE: '>=',
ast.Gt: '>',
}
@staticmethod
def build_Attribute(ctx, expr):
# NB: the only attributes we support are for getting methods
value = build_expr(ctx, expr.value)
# <sigh> name is just a string, so it's not annotated in any way.
source = ctx.source
pos = find_after(ctx, value.range().end, '.').end # Start with the dot
while source[pos] in string.whitespace: # Skip whitespace
pos += 1
start_pos = pos
while source[pos] in _identifier_chars: # Find the identifier itself
pos += 1
name_range = ctx.make_raw_range(start_pos, pos)
return Select(value, Ident(name_range, expr.attr))
@staticmethod
def build_Call(ctx, expr):
func = build_expr(ctx, expr.func)
args = [build_expr(ctx, py_arg) for py_arg in expr.args]
if hasattr(expr, 'starargs') and expr.starargs:
stararg_expr = build_expr(ctx, expr.starargs)
args += [Starred(stararg_expr.range(), stararg_expr)]
kwargs = []
for kw in expr.keywords:
kw_expr = build_expr(ctx, kw.value)
# XXX: we could do a better job at figuring out the range for the name here
kwargs.append(Attribute(Ident(kw_expr.range(), kw.arg), kw_expr))
return Apply(func, args, kwargs)
@staticmethod
def build_Name(ctx, expr):
r = ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + len(expr.id))
if expr.id.startswith(_reserved_prefix):
raise NotSupportedError(r, "names of variables used in JIT-ed functions "
"can't start with " + _reserved_prefix)
if expr.id == "True":
return TrueLiteral(r)
elif expr.id == "False":
return FalseLiteral(r)
elif expr.id == "None":
return NoneLiteral(r)
return Var(Ident(r, expr.id))
@staticmethod
def build_NameConstant(ctx, expr):
r = ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + len(str(expr.value)))
if expr.value is True:
return TrueLiteral(r)
elif expr.value is False:
return FalseLiteral(r)
elif expr.value is None:
return NoneLiteral(r)
else:
raise ValueError("Name constant value unsupported: " + str(expr.value))
@staticmethod
def build_BinOp(ctx, expr):
lhs = build_expr(ctx, expr.left)
rhs = build_expr(ctx, expr.right)
op = type(expr.op)
op_token = ExprBuilder.binop_map.get(op)
if op_token is None:
err_range = ctx.make_raw_range(lhs.range().end, rhs.range().start)
raise NotSupportedError(err_range, "unsupported binary operator: " + op.__name__)
return BinOp(op_token, lhs, rhs)
@staticmethod
def build_UnaryOp(ctx, expr):
sub_expr = build_expr(ctx, expr.operand)
op = type(expr.op)
op_token = ExprBuilder.unop_map.get(op)
r = ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + len(op_token))
if op_token is None:
err_range = ctx.make_raw_range(r.start, sub_expr.range().end)
raise NotSupportedError(err_range, "unsupported unary operator: " + op.__name__)
return UnaryOp(r, op_token, sub_expr)
@staticmethod
def build_BoolOp(ctx, expr):
if len(expr.values) < 2:
raise AssertionError("expected at least 2 values in BoolOp, but got " + str(len(expr.values)))
sub_exprs = [build_expr(ctx, sub_expr) for sub_expr in expr.values]
op = type(expr.op)
op_token = ExprBuilder.boolop_map.get(op)
if op_token is None:
err_range = ctx.make_raw_range(sub_exprs[0].range().end, sub_exprs[1].range().start)
raise NotSupportedError(err_range, "unsupported boolean operator: " + op.__name__)
lhs = sub_exprs[0]
for rhs in sub_exprs[1:]:
lhs = BinOp(op_token, lhs, rhs)
return lhs
@staticmethod
def build_IfExp(ctx, expr):
return TernaryIf(build_expr(ctx, expr.test),
build_expr(ctx, expr.body),
build_expr(ctx, expr.orelse))
@staticmethod
def build_Compare(ctx, expr):
operands = [build_expr(ctx, e) for e in [expr.left] + list(expr.comparators)]
result = None
for lhs, op_, rhs in zip(operands, expr.ops, operands[1:]):
op = type(op_)
op_token = ExprBuilder.cmpop_map.get(op)
if op_token is None:
err_range = ctx.make_raw_range(lhs.range().end, rhs.range().start)
raise NotSupportedError(err_range, "unsupported comparison operator: " + op.__name__)
cmp_expr = BinOp(op_token, lhs, rhs)
if result is None:
result = cmp_expr
else:
result = BinOp('and', result, cmp_expr)
return result
@staticmethod
def build_Subscript(ctx, expr):
base = build_expr(ctx, expr.value)
sub_type = type(expr.slice)
if sub_type is ast.Index:
index = build_expr(ctx, expr.slice.value)
return Gather(base, index)
elif sub_type is ast.Slice:
lower = build_expr(ctx, expr.slice.lower) if expr.slice.lower is not None else None
upper = build_expr(ctx, expr.slice.upper) if expr.slice.upper is not None else None
if expr.slice.step is not None:
step = build_expr(ctx, expr.slice.step)
raise NotSupportedError(step.range(), "slices with ranges are not supported yet")
return Slice(base, lower, upper)
elif sub_type is ast.ExtSlice:
raise NotSupportedError(base.range(), "slicing multiple dimensions at the same time isn't supported yet")
else: # Ellipsis (can only happen in Python 2)
raise NotSupportedError(base.range(), "ellipsis is not supported")
@staticmethod
def build_List(ctx, expr):
return ListLiteral(ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + 1),
[build_expr(ctx, e) for e in expr.elts])
@staticmethod
def build_Tuple(ctx, expr):
return ListLiteral(ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + 1),
[build_expr(ctx, e) for e in expr.elts])
@staticmethod
def build_Num(ctx, expr):
value = str(expr.n)
r = ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + len(value))
return Const(r, value)
@staticmethod
def build_Starred(ctx, expr):
r = ctx.make_range(expr.lineno, expr.col_offset, expr.col_offset + 1)
return Starred(r, build_expr(ctx, expr.value))
build_expr = ExprBuilder()
build_stmt = StmtBuilder()
def find_after(ctx, pos, substr, offsets=(0, 0)):
new_pos = pos + ctx.source[pos:].index(substr)
return ctx.make_raw_range(new_pos + offsets[0], new_pos + len(substr) + offsets[1])
def find_before(ctx, pos, substr, offsets=(0, 0)):
new_pos = ctx.source[:pos].rindex(substr)
return ctx.make_raw_range(new_pos + offsets[0], new_pos + len(substr) + offsets[1])