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from collections import defaultdict
from import Sequence
import types as pytypes
import weakref
import threading
import contextlib
import operator
import numba
from numba.core import types, errors
from numba.core.typeconv import Conversion, rules
from numba.core.typing import templates
from .typeof import typeof, Purpose
from numba.core import utils
class Rating(object):
__slots__ = 'promote', 'safe_convert', "unsafe_convert"
def __init__(self):
self.promote = 0
self.safe_convert = 0
self.unsafe_convert = 0
def astuple(self):
"""Returns a tuple suitable for comparing with the worse situation
start first.
return (self.unsafe_convert, self.safe_convert, self.promote)
def __add__(self, other):
if type(self) is not type(other):
return NotImplemented
rsum = Rating()
rsum.promote = self.promote + other.promote
rsum.safe_convert = self.safe_convert + other.safe_convert
rsum.unsafe_convert = self.unsafe_convert + other.unsafe_convert
return rsum
class CallStack(Sequence):
A compile-time call stack
def __init__(self):
self._stack = []
self._lock = threading.RLock()
def __getitem__(self, index):
Returns item in the stack where index=0 is the top and index=1 is
the second item from the top.
return self._stack[len(self) - index - 1]
def __len__(self):
return len(self._stack)
def register(self, typeinfer, func_id, args):
# guard compiling the same function with the same signature
if self.match(func_id.func, args):
msg = "compiler re-entrant to the same function signature"
raise RuntimeError(msg)
self._stack.append(CallFrame(typeinfer, func_id, args))
def finditer(self, py_func):
Yields frame that matches the function object starting from the top
of stack.
for frame in self:
if frame.func_id.func is py_func:
yield frame
def findfirst(self, py_func):
Returns the first result from `.finditer(py_func)`; or None if no match.
return next(self.finditer(py_func))
except StopIteration:
def match(self, py_func, args):
Returns first function that matches *py_func* and the arguments types in
*args*; or, None if no match.
for frame in self.finditer(py_func):
if frame.args == args:
return frame
class CallFrame(object):
A compile-time call frame
def __init__(self, typeinfer, func_id, args):
self.typeinfer = typeinfer
self.func_id = func_id
self.args = args
self._inferred_retty = set()
def __repr__(self):
return "CallFrame({}, {})".format(self.func_id, self.args)
def add_return_type(self, return_type):
"""Add *return_type* to the list of inferred return-types.
If there are too many, raise `TypingError`.
# The maximum limit is picked arbitrarily.
# Don't think that this needs to be user configurable.
if len(self._inferred_retty) >= RETTY_LIMIT:
m = "Return type of recursive function does not converge"
raise errors.TypingError(m)
class BaseContext(object):
"""A typing context for storing function typing constrain template.
def __init__(self):
# A list of installed registries
self._registries = {}
# Typing declarations extracted from the registries or other sources
self._functions = defaultdict(list)
self._attributes = defaultdict(list)
self._globals = utils.UniqueDict() = rules.default_type_manager
self.callstack = CallStack()
# Initialize
def init(self):
Initialize the typing context. Can be overridden by subclasses.
def refresh(self):
Refresh context with new declarations from known registries.
Useful for third-party extensions.
# Some extensions may have augmented the builtin registry
def explain_function_type(self, func):
Returns a string description of the type of a function
desc = []
defns = []
param = False
if isinstance(func, types.Callable):
sigs, param = func.get_call_signatures()
elif func in self._functions:
for tpl in self._functions[func]:
param = param or hasattr(tpl, 'generic')
defns.extend(getattr(tpl, 'cases', []))
msg = "No type info available for {func!r} as a callable."
if defns:
desc = ['Known signatures:']
for sig in defns:
desc.append(' * {0}'.format(sig))
return '\n'.join(desc)
def resolve_function_type(self, func, args, kws):
Resolve function type *func* for argument types *args* and *kws*.
A signature is returned.
# Prefer user definition first
res = self._resolve_user_function_type(func, args, kws)
except errors.TypingError as e:
# Capture any typing error
last_exception = e
res = None
last_exception = None
# Return early we there's a working user function
if res is not None:
return res
# Check builtin functions
res = self._resolve_builtin_function_type(func, args, kws)
# Re-raise last_exception if no function type has been found
if res is None and last_exception is not None:
raise last_exception
return res
def _resolve_builtin_function_type(self, func, args, kws):
# NOTE: we should reduce usage of this
if func in self._functions:
# Note: Duplicating code with types.Function.get_call_type().
# *defns* are CallTemplates.
defns = self._functions[func]
for defn in defns:
for support_literals in [True, False]:
if support_literals:
res = defn.apply(args, kws)
fixedargs = [types.unliteral(a) for a in args]
res = defn.apply(fixedargs, kws)
if res is not None:
return res
def _resolve_user_function_type(self, func, args, kws, literals=None):
# It's not a known function type, perhaps it's a global?
functy = self._lookup_global(func)
if functy is not None:
func = functy
if isinstance(func, types.Type):
# If it's a type, it may support a __call__ method
func_type = self.resolve_getattr(func, "__call__")
if func_type is not None:
# The function has a __call__ method, type its call.
return self.resolve_function_type(func_type, args, kws)
if isinstance(func, types.Callable):
# XXX fold this into the __call__ attribute logic?
return func.get_call_type(self, args, kws)
def _get_attribute_templates(self, typ):
Get matching AttributeTemplates for the Numba type.
if typ in self._attributes:
for attrinfo in self._attributes[typ]:
yield attrinfo
for cls in type(typ).__mro__:
if cls in self._attributes:
for attrinfo in self._attributes[cls]:
yield attrinfo
def resolve_getattr(self, typ, attr):
Resolve getting the attribute *attr* (a string) on the Numba type.
The attribute's type is returned, or None if resolution failed.
def core(typ):
out = self.find_matching_getattr_template(typ, attr)
if out:
return out['return_type']
out = core(typ)
if out is not None:
return out
# Try again without literals
out = core(types.unliteral(typ))
if out is not None:
return out
if isinstance(typ, types.Module):
attrty = self.resolve_module_constants(typ, attr)
if attrty is not None:
return attrty
def find_matching_getattr_template(self, typ, attr):
for template in self._get_attribute_templates(typ):
return_type = template.resolve(typ, attr)
if return_type is not None:
return {
'template': template,
'return_type': return_type,
def resolve_setattr(self, target, attr, value):
Resolve setting the attribute *attr* (a string) on the *target* type
to the given *value* type.
A function signature is returned, or None if resolution failed.
for attrinfo in self._get_attribute_templates(target):
expectedty = attrinfo.resolve(target, attr)
# NOTE: convertibility from *value* to *expectedty* is left to
# the caller.
if expectedty is not None:
return templates.signature(types.void, target, expectedty)
def resolve_static_getitem(self, value, index):
assert not isinstance(index, types.Type), index
args = value, index
kws = ()
return self.resolve_function_type("static_getitem", args, kws)
def resolve_static_setitem(self, target, index, value):
assert not isinstance(index, types.Type), index
args = target, index, value
kws = {}
return self.resolve_function_type("static_setitem", args, kws)
def resolve_setitem(self, target, index, value):
assert isinstance(index, types.Type), index
fnty = self.resolve_value_type(operator.setitem)
sig = fnty.get_call_type(self, (target, index, value), {})
return sig
def resolve_delitem(self, target, index):
args = target, index
kws = {}
fnty = self.resolve_value_type(operator.delitem)
sig = fnty.get_call_type(self, args, kws)
return sig
def resolve_module_constants(self, typ, attr):
Resolve module-level global constants.
Return None or the attribute type
assert isinstance(typ, types.Module)
attrval = getattr(typ.pymod, attr)
return self.resolve_value_type(attrval)
except ValueError:
def resolve_argument_type(self, val):
Return the numba type of a Python value that is being used
as a function argument. Integer types will all be considered
int64, regardless of size.
ValueError is raised for unsupported types.
return typeof(val, Purpose.argument)
except ValueError:
if numba.cuda.is_cuda_array(val):
return typeof(numba.cuda.as_cuda_array(val), Purpose.argument)
def resolve_value_type(self, val):
Return the numba type of a Python value that is being used
as a runtime constant.
ValueError is raised for unsupported types.
ty = typeof(val, Purpose.constant)
except ValueError as e:
# Make sure the exception doesn't hold a reference to the user
# value.
typeof_exc = utils.erase_traceback(e)
return ty
if isinstance(val, types.ExternalFunction):
return val
# Try to look up target specific typing information
ty = self._get_global_type(val)
if ty is not None:
return ty
raise typeof_exc
def resolve_value_type_prefer_literal(self, value):
"""Resolve value type and prefer Literal types whenever possible.
lit = types.maybe_literal(value)
if lit is None:
return self.resolve_value_type(value)
return lit
def _get_global_type(self, gv):
ty = self._lookup_global(gv)
if ty is not None:
return ty
if isinstance(gv, pytypes.ModuleType):
return types.Module(gv)
def _load_builtins(self):
# Initialize declarations
from numba.core.typing import builtins, arraydecl, npdatetime # noqa: F401, E501
from numba.core.typing import ctypes_utils, bufproto # noqa: F401, E501
from numba.core.unsafe import eh # noqa: F401
def load_additional_registries(self):
Load target-specific registries. Can be overridden by subclasses.
def install_registry(self, registry):
Install a *registry* (a templates.Registry instance) of function,
attribute and global declarations.
loader = self._registries[registry]
except KeyError:
loader = templates.RegistryLoader(registry)
self._registries[registry] = loader
for ftcls in loader.new_registrations('functions'):
for ftcls in loader.new_registrations('attributes'):
for gv, gty in loader.new_registrations('globals'):
existing = self._lookup_global(gv)
if existing is None:
self.insert_global(gv, gty)
# A type was already inserted, see if we can add to it
newty = existing.augment(gty)
if newty is None:
raise TypeError("cannot augment %s with %s"
% (existing, gty))
self._insert_global(gv, newty)
def _lookup_global(self, gv):
Look up the registered type for global value *gv*.
gv = weakref.ref(gv)
except TypeError:
return self._globals.get(gv, None)
except TypeError:
# Unhashable type
return None
def _insert_global(self, gv, gty):
Register type *gty* for value *gv*. Only a weak reference
to *gv* is kept, if possible.
def on_disposal(wr, pop=self._globals.pop):
# pop() is pre-looked up to avoid a crash late at shutdown on 3.5
# (
gv = weakref.ref(gv, on_disposal)
except TypeError:
self._globals[gv] = gty
def _remove_global(self, gv):
Remove the registered type for global value *gv*.
gv = weakref.ref(gv)
except TypeError:
del self._globals[gv]
def insert_global(self, gv, gty):
self._insert_global(gv, gty)
def insert_attributes(self, at):
key = at.key
def insert_function(self, ft):
key = ft.key
def insert_user_function(self, fn, ft):
"""Insert a user function.
- fn:
object used as callee
- ft:
function template
self._insert_global(fn, types.Function(ft))
def can_convert(self, fromty, toty):
Check whether conversion is possible from *fromty* to *toty*.
If successful, return a numba.typeconv.Conversion instance;
otherwise None is returned.
if fromty == toty:
return Conversion.exact
# First check with the type manager (some rules are registered
# at startup there, see numba.typeconv.rules)
conv =, toty)
if conv is not None:
return conv
# Fall back on type-specific rules
forward = fromty.can_convert_to(self, toty)
backward = toty.can_convert_from(self, fromty)
if backward is None:
return forward
elif forward is None:
return backward
return min(forward, backward)
def _rate_arguments(self, actualargs, formalargs, unsafe_casting=True,
Rate the actual arguments for compatibility against the formal
arguments. A Rating instance is returned, or None if incompatible.
if len(actualargs) != len(formalargs):
return None
rate = Rating()
for actual, formal in zip(actualargs, formalargs):
conv = self.can_convert(actual, formal)
if conv is None:
return None
elif not unsafe_casting and conv >= Conversion.unsafe:
return None
elif exact_match_required and conv != Conversion.exact:
return None
if conv == Conversion.promote:
rate.promote += 1
elif conv ==
rate.safe_convert += 1
elif conv == Conversion.unsafe:
rate.unsafe_convert += 1
elif conv == Conversion.exact:
raise Exception("unreachable", conv)
return rate
def install_possible_conversions(self, actualargs, formalargs):
Install possible conversions from the actual argument types to
the formal argument types in the C++ type manager.
Return True if all arguments can be converted.
if len(actualargs) != len(formalargs):
return False
for actual, formal in zip(actualargs, formalargs):
if, formal) is not None:
# This conversion is already known
conv = self.can_convert(actual, formal)
if conv is None:
return False
assert conv is not Conversion.exact, formal, conv)
return True
def resolve_overload(self, key, cases, args, kws,
allow_ambiguous=True, unsafe_casting=True,
Given actual *args* and *kws*, find the best matching
signature in *cases*, or None if none matches.
*key* is used for error reporting purposes.
If *allow_ambiguous* is False, a tie in the best matches
will raise an error.
If *unsafe_casting* is False, unsafe casting is forbidden.
assert not kws, "Keyword arguments are not supported, yet"
options = {
'unsafe_casting': unsafe_casting,
'exact_match_required': exact_match_required,
# Rate each case
candidates = []
for case in cases:
if len(args) == len(case.args):
rating = self._rate_arguments(args, case.args, **options)
if rating is not None:
candidates.append((rating.astuple(), case))
# Find the best case
candidates.sort(key=lambda i: i[0])
if candidates:
best_rate, best = candidates[0]
if not allow_ambiguous:
# Find whether there is a tie and if so, raise an error
tied = []
for rate, case in candidates:
if rate != best_rate:
if len(tied) > 1:
args = (key, args, '\n'.join(map(str, tied)))
msg = "Ambiguous overloading for %s %s:\n%s" % args
raise TypeError(msg)
# Simply return the best matching candidate in order.
# If there is a tie, since list.sort() is stable, the first case
# in the original order is returned.
# (this can happen if e.g. a function template exposes
# (int32, int32) -> int32 and (int64, int64) -> int64,
# and you call it with (int16, int16) arguments)
return best
def unify_types(self, *typelist):
# Sort the type list according to bit width before doing
# pairwise unification (with thanks to aterrel).
def keyfunc(obj):
"""Uses bitwidth to order numeric-types.
Fallback to stable, deterministic sort.
return getattr(obj, 'bitwidth', 0)
typelist = sorted(typelist, key=keyfunc)
unified = typelist[0]
for tp in typelist[1:]:
unified = self.unify_pairs(unified, tp)
if unified is None:
return unified
def unify_pairs(self, first, second):
Try to unify the two given types. A third type is returned,
or None in case of failure.
if first == second:
return first
if first is types.undefined:
return second
elif second is types.undefined:
return first
# Types with special unification rules
unified = first.unify(self, second)
if unified is not None:
return unified
unified = second.unify(self, first)
if unified is not None:
return unified
# Other types with simple conversion rules
conv = self.can_convert(fromty=first, toty=second)
if conv is not None and conv <=
# Can convert from first to second
return second
conv = self.can_convert(fromty=second, toty=first)
if conv is not None and conv <=
# Can convert from second to first
return first
if isinstance(first, types.Literal) or \
isinstance(second, types.Literal):
first = types.unliteral(first)
second = types.unliteral(second)
return self.unify_pairs(first, second)
# Cannot unify
return None
class Context(BaseContext):
def load_additional_registries(self):
from . import (
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