scipy/_lib/_uarray/_uarray

Bug Summary

File:	/tmp/pyrefcon/scipy/scipy/_lib/_uarray/_uarray_dispatch.cxx
Warning:	line 351, column 37 PyObject ownership leak with reference count of 1

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name _uarray_dispatch.cxx -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-output=html -analyzer-checker=python -analyzer-disable-checker=deadcode -analyzer-config prune-paths=true,suppress-c++-stdlib=true,suppress-null-return-paths=false,crosscheck-with-z3=true,model-path=/opt/pyrefcon/lib/pyrefcon/models/models -analyzer-config experimental-enable-naive-ctu-analysis=true,ctu-dir=/tmp/pyrefcon/scipy/csa-scan,ctu-index-name=/tmp/pyrefcon/scipy/csa-scan/externalDefMap.txt,ctu-invocation-list=/tmp/pyrefcon/scipy/csa-scan/invocations.yaml,display-ctu-progress=false -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debug-info-kind=limited -dwarf-version=4 -debugger-tuning=gdb -fcoverage-compilation-dir=/tmp/pyrefcon/scipy -resource-dir /opt/pyrefcon/lib/clang/13.0.0 -isystem /opt/pyrefcon/lib/pyrefcon/models/python3.8 -D NDEBUG -D _FORTIFY_SOURCE=2 -I /usr/lib/python3/dist-packages/numpy/core/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /opt/pyrefcon/lib/clang/13.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-result -Wsign-compare -Wall -Wformat -Werror=format-security -Wformat -Werror=format-security -Wdate-time -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/tmp/pyrefcon/scipy -ferror-limit 19 -fvisibility hidden -fwrapv -pthread -stack-protector 2 -fgnuc-version=4.2.1 -fcxx-exceptions -fexceptions -vectorize-loops -vectorize-slp -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/pyrefcon/scipy/csa-scan/reports -x c++ scipy/_lib/_uarray/_uarray_dispatch.cxx

scipy/_lib/_uarray/_uarray_dispatch.cxx

→

1#include "small_dynamic_array.h"
2#include "vectorcall.h"

4#include <Python.h>

6#include <algorithm>
7#include <cstddef>
8#include <new>
9#include <stdexcept>
10#include <string>
11#include <unordered_map>
12#include <utility>
13#include <vector>


16namespace {

18/** Handle to a python object that automatically DECREFs */
19class py_ref {
explicit py_ref(PyObject * object): obj_(object) {}

22public:
py_ref() noexcept: obj_(nullptr) {}
py_ref(std::nullptr_t) noexcept: py_ref() {}

py_ref(const py_ref & other) noexcept: obj_(other.obj_) { Py_XINCREF(obj_)_Py_XINCREF(((PyObject*)(obj_))); }
py_ref(py_ref && other) noexcept: obj_(other.obj_) { other.obj_ = nullptr; }

/** Construct from new reference (No INCREF) */
static py_ref steal(PyObject * object) { return py_ref(object); }

/** Construct from borrowed reference (and INCREF) */
static py_ref ref(PyObject * object) {
  Py_XINCREF(object)_Py_XINCREF(((PyObject*)(object)));
  return py_ref(object);
}

~py_ref() { Py_XDECREF(obj_)_Py_XDECREF(((PyObject*)(obj_))); }

py_ref & operator=(const py_ref & other) noexcept {
  py_ref(other).swap(*this);
  return *this;
}

py_ref & operator=(py_ref && other) noexcept {
  py_ref(std::move(other)).swap(*this);
  return *this;
}

friend bool operator==(const py_ref & lhs, const py_ref & rhs) {
  return lhs.obj_ == rhs.obj_;
}
friend bool operator==(PyObject * lhs, const py_ref & rhs) {
  return lhs == rhs.obj_;
}
friend bool operator==(const py_ref & lhs, PyObject * rhs) {
  return lhs.obj_ == rhs;
}
friend bool operator!=(const py_ref & lhs, const py_ref & rhs) {
  return lhs.obj_ != rhs.obj_;
}
friend bool operator!=(PyObject * lhs, const py_ref & rhs) {
  return lhs != rhs.obj_;
}
friend bool operator!=(const py_ref & lhs, PyObject * rhs) {
  return lhs.obj_ != rhs;
}

void swap(py_ref & other) noexcept { std::swap(other.obj_, obj_); }

explicit operator bool() const { return obj_ != nullptr; }

PyObject * get() const { return obj_; }
PyObject * release() {
  PyObject * t = obj_;
  obj_ = nullptr;
  return t;
}
void reset() { Py_CLEAR(obj_)do { PyObject *_py_tmp = ((PyObject*)(obj_)); if (_py_tmp != __null
) { (obj_) = __null; _Py_DECREF(((PyObject*)(_py_tmp))); } } while
 (0); }

81private:
PyObject * obj_;
83};

85PyObject * py_get(const py_ref & ref) { return ref.get(); }
86PyObject * py_get(PyObject * obj) { return obj; }

88/** Make tuple from variadic set of PyObjects */
89template <typename... Ts>
90py_ref py_make_tuple(const Ts &... args) {
return py_ref::steal(PyTuple_Pack(sizeof...(args), py_get(args)...));
92}

94py_ref py_bool(bool input) { return py_ref::ref(input ? Py_True((PyObject *) &_Py_TrueStruct) : Py_False((PyObject *) &_Py_FalseStruct)); }

96template <typename T, size_t N>
97constexpr size_t array_size(const T (&array)[N]) {
return N;
99}

101struct backend_options {
py_ref backend;
bool coerce = false;
bool only = false;

bool operator==(const backend_options & other) const {
  return (
      backend == other.backend && coerce == other.coerce &&
      only == other.only);
}

bool operator!=(const backend_options & other) const {
  return !(*this == other);
}
115};

117struct global_backends {
backend_options global;
std::vector<py_ref> registered;
bool try_global_backend_last = false;
121};

123struct local_backends {
std::vector<py_ref> skipped;
std::vector<backend_options> preferred;
126};

128using global_state_t = std::unordered_map<std::string, global_backends>;
129using local_state_t = std::unordered_map<std::string, local_backends>;

131static py_ref BackendNotImplementedError;
132static global_state_t global_domain_map;
133thread_local global_state_t * current_global_state = &global_domain_map;
134thread_local global_state_t thread_local_domain_map;
135thread_local local_state_t local_domain_map;

137/** Constant Python string identifiers

139Using these with PyObject_GetAttr is faster than PyObject_GetAttrString which
140has to create a new python string internally.
*/
142struct {
py_ref ua_convert;
py_ref ua_domain;
py_ref ua_function;

bool init() {
  ua_convert = py_ref::steal(PyUnicode_InternFromString("__ua_convert__"));
  if (!ua_convert)
    return false;

  ua_domain = py_ref::steal(PyUnicode_InternFromString("__ua_domain__"));
  if (!ua_domain)
    return false;

  ua_function = py_ref::steal(PyUnicode_InternFromString("__ua_function__"));
  if (!ua_function)
    return false;

  return true;
}

void clear() {
  ua_convert.reset();
  ua_domain.reset();
  ua_function.reset();
}
168} identifiers;

170bool domain_validate(PyObject * domain) {
if (!PyUnicode_Check(domain)((((((PyObject*)(domain))->ob_type))->tp_flags & ((
1UL << 28))) != 0)) {
  PyErr_SetString(PyExc_TypeError, "__ua_domain__ must be a string");
  return false;
}

auto size = PyUnicode_GetLength(domain);
if (size == 0) {
  PyErr_SetString(PyExc_ValueError, "__ua_domain__ must be non-empty");
  return false;
}

return true;
183}

185std::string domain_to_string(PyObject * domain) {
if (!domain_validate(domain)) {
  return {};
}

Py_ssize_t size;
const char * str = PyUnicode_AsUTF8AndSize(domain, &size);
if (!str)
  return {};

if (size == 0) {
  PyErr_SetString(PyExc_ValueError, "__ua_domain__ must be non-empty");
  return {};
}

return std::string(str, size);
201}

203Py_ssize_t backend_get_num_domains(PyObject * backend) {
auto domain =
    py_ref::steal(PyObject_GetAttr(backend, identifiers.ua_domain.get()));
if (!domain)
  return -1;

if (PyUnicode_Check(domain.get())((((((PyObject*)(domain.get()))->ob_type))->tp_flags &
 ((1UL << 28))) != 0)) {
  return 1;
}

if (!PySequence_Check(domain.get())) {
  PyErr_SetString(
      PyExc_TypeError,
      "__ua_domain__ must be a string or sequence of strings");
  return -1;
}

return PySequence_Size(domain.get());
221}

223enum class LoopReturn { Continue, Break, Error };

225template <typename Func>
226LoopReturn backend_for_each_domain(PyObject * backend, Func f) {
auto domain =
    py_ref::steal(PyObject_GetAttr(backend, identifiers.ua_domain.get()));
if (!domain)
  return LoopReturn::Error;

if (PyUnicode_Check(domain.get())((((((PyObject*)(domain.get()))->ob_type))->tp_flags &
 ((1UL << 28))) != 0)) {
  return f(domain.get());
}

if (!PySequence_Check(domain.get())) {
  PyErr_SetString(
      PyExc_TypeError,
      "__ua_domain__ must be a string or sequence of strings");
  return LoopReturn::Error;
}

auto size = PySequence_Size(domain.get());
if (size < 0)
  return LoopReturn::Error;
if (size == 0) {
  PyErr_SetString(PyExc_ValueError, "__ua_domain__ lists must be non-empty");
  return LoopReturn::Error;
}

for (Py_ssize_t i = 0; i < size; ++i) {
  auto dom = py_ref::steal(PySequence_GetItem(domain.get(), i));
  if (!dom)
    return LoopReturn::Error;

  auto res = f(dom.get());
  if (res != LoopReturn::Continue) {
    return res;
  }
}
return LoopReturn::Continue;
262}

264template <typename Func>
265LoopReturn backend_for_each_domain_string(PyObject * backend, Func f) {
return backend_for_each_domain(backend, [&](PyObject * domain) {
  auto domain_string = domain_to_string(domain);
  if (domain_string.empty()) {
    return LoopReturn::Error;
  }
  return f(domain_string);
});
273}

275bool backend_validate_ua_domain(PyObject * backend) {
const auto res = backend_for_each_domain(backend, [&](PyObject * domain) {
  return domain_validate(domain) ? LoopReturn::Continue : LoopReturn::Error;
});
return (res != LoopReturn::Error);
280}

282struct BackendState {
PyObject_HEADPyObject ob_base;
global_state_t globals;
local_state_t locals;
bool use_thread_local_globals = true;

static void dealloc(BackendState * self) {
  self->~BackendState();
  Py_TYPE(self)(((PyObject*)(self))->ob_type)->tp_free(self);
}

static PyObject * new_(
    PyTypeObject * type, PyObject * args, PyObject * kwargs) {
  auto self = reinterpret_cast<BackendState *>(type->tp_alloc(type, 0));
  if (self == nullptr)
    return nullptr;

  // Placement new
  self = new (self) BackendState;
  return reinterpret_cast<PyObject *>(self);
}

static PyObject * pickle_(BackendState * self) {
  try {
    py_ref py_global = BackendState::convert_py(self->globals);
    py_ref py_locals = BackendState::convert_py(self->locals);
    py_ref py_use_local_globals =
        BackendState::convert_py(self->use_thread_local_globals);

    return py_make_tuple(py_global, py_locals, py_use_local_globals)
        .release();
  } catch (std::runtime_error &) {
    return nullptr;
  }
}

static PyObject * unpickle_(PyObject * cls, PyObject * args) {
  try {
    PyObject *py_locals, *py_global;
    py_ref ref =
        py_ref::steal(Q_PyObject_Vectorcall(cls, nullptr, 0, nullptr));
    BackendState * output = reinterpret_cast<BackendState *>(ref.get());
    if (output == nullptr)
      return nullptr;

    int use_thread_local_globals;
    if (!PyArg_ParseTuple(
            args, "OOp", &py_global, &py_locals, &use_thread_local_globals))
      return nullptr;
    local_state_t locals = convert_local_state(py_locals);
    global_state_t globals = convert_global_state(py_global);

    output->locals = std::move(locals);
    output->globals = std::move(globals);
    output->use_thread_local_globals = use_thread_local_globals;

    return ref.release();
  } catch (std::invalid_argument &) {
    return nullptr;
  } catch (std::bad_alloc &) {
    PyErr_NoMemory();
    return nullptr;
  }
}

template <typename T, typename Convertor>
static std::vector<T> convert_iter(
    PyObject * input, Convertor item_convertor) {
  std::vector<T> output;
  py_ref iterator = py_ref::steal(PyObject_GetIter(input));
4
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Calling 'PyObject_GetIter'→
6
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Returning from 'PyObject_GetIter'→
11
←
PyObject ownership leak with reference count of 1
  if (!iterator)
7
←
Taking false branch→
    throw std::invalid_argument("");

  py_ref item;
  while ((item = py_ref::steal(PyIter_Next(iterator.get())))) {
8
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Loop condition is false. Execution continues on line 360→
    output.push_back(item_convertor(item.get()));
  }

  if (PyErr_Occurred())
9
←
Assuming the condition is true→
10
←
Taking true branch→
    throw std::invalid_argument("");

  return output;
}

template <
    typename K, typename V, typename KeyConvertor, typename ValueConvertor>
static std::unordered_map<K, V> convert_dict(
    PyObject * input, KeyConvertor key_convertor,
    ValueConvertor value_convertor) {
  std::unordered_map<K, V> output;

  if (!PyDict_Check(input)((((((PyObject*)(input))->ob_type))->tp_flags & ((1UL
 << 29))) != 0))
    throw std::invalid_argument("");

  PyObject *key, *value;
  Py_ssize_t pos = 0;

  while (PyDict_Next(input, &pos, &key, &value)) {
    output[key_convertor(key)] = value_convertor(value);
  }

  if (PyErr_Occurred())
    throw std::invalid_argument("");

  return output;
}

static std::string convert_domain(PyObject * input) {
  std::string output = domain_to_string(input);
  if (output.empty())
    throw std::invalid_argument("");

  return output;
}

static backend_options convert_backend_options(PyObject * input) {
  backend_options output;
  int coerce, only;
  PyObject * py_backend;
  if (!PyArg_ParseTuple(input, "Opp", &py_backend, &coerce, &only))
    throw std::invalid_argument("");

  if (py_backend != Py_None(&_Py_NoneStruct)) {
    output.backend = py_ref::ref(py_backend);
  }
  output.coerce = coerce;
  output.only = only;

  return output;
}

static py_ref convert_backend(PyObject * input) { return py_ref::ref(input); }

static local_backends convert_local_backends(PyObject * input) {
  PyObject *py_skipped, *py_preferred;
  if (!PyArg_ParseTuple(input, "OO", &py_skipped, &py_preferred))
    throw std::invalid_argument("");

  local_backends output;
  output.skipped =
      convert_iter<py_ref>(py_skipped, BackendState::convert_backend);
  output.preferred = convert_iter<backend_options>(
      py_preferred, BackendState::convert_backend_options);

  return output;
}

static global_backends convert_global_backends(PyObject * input) {
  PyObject *py_global, *py_registered;
  int try_global_backend_last;
  if (!PyArg_ParseTuple(
1
Assuming the condition is false→
2
←
Taking false branch→
          input, "OOp", &py_global, &py_registered, &try_global_backend_last))
    throw std::invalid_argument("");

  global_backends output;
  output.global = BackendState::convert_backend_options(py_global);
  output.registered =
      convert_iter<py_ref>(py_registered, BackendState::convert_backend);
3
←
Calling 'BackendState::convert_iter'→
  output.try_global_backend_last = try_global_backend_last;

  return output;
}

static global_state_t convert_global_state(PyObject * input) {
  return convert_dict<std::string, global_backends>(
      input, BackendState::convert_domain,
      BackendState::convert_global_backends);
}

static local_state_t convert_local_state(PyObject * input) {
  return convert_dict<std::string, local_backends>(
      input, BackendState::convert_domain,
      BackendState::convert_local_backends);
}

static py_ref convert_py(py_ref input) { return input; }

static py_ref convert_py(bool input) { return py_bool(input); }

static py_ref convert_py(backend_options input) {
  if (!input.backend) {
    input.backend = py_ref::ref(Py_None(&_Py_NoneStruct));
  }
  py_ref output = py_make_tuple(
      input.backend, py_bool(input.coerce), py_bool(input.only));
  if (!output)
    throw std::runtime_error("");
  return output;
}

static py_ref convert_py(const std::string & input) {
  py_ref output =
      py_ref::steal(PyUnicode_FromStringAndSize(input.c_str(), input.size()));
  if (!output)
    throw std::runtime_error("");
  return output;
}

template <typename T>
static py_ref convert_py(const std::vector<T> & input) {
  py_ref output = py_ref::steal(PyList_New(input.size()));

  if (!output)
    throw std::runtime_error("");

  for (size_t i = 0; i < input.size(); i++) {
    py_ref element = convert_py(input[i]);
    PyList_SET_ITEM(output.get(), i, element.release())PyList_SetItem(output.get(), i, element.release());
  }

  return output;
}

static py_ref convert_py(const local_backends & input) {
  py_ref py_skipped = BackendState::convert_py(input.skipped);
  py_ref py_preferred = BackendState::convert_py(input.preferred);
  py_ref output = py_make_tuple(py_skipped, py_preferred);

  if (!output)
    throw std::runtime_error("");

  return output;
}

static py_ref convert_py(const global_backends & input) {
  py_ref py_globals = BackendState::convert_py(input.global);
  py_ref py_registered = BackendState::convert_py(input.registered);
  py_ref output = py_make_tuple(
      py_globals, py_registered, py_bool(input.try_global_backend_last));

  if (!output)
    throw std::runtime_error("");

  return output;
}

template <typename K, typename V>
static py_ref convert_py(const std::unordered_map<K, V> & input) {
  py_ref output = py_ref::steal(PyDict_New());

  if (!output)
    throw std::runtime_error("");

  for (const auto & kv : input) {
    py_ref py_key = convert_py(kv.first);
    py_ref py_value = convert_py(kv.second);

    if (PyDict_SetItem(output.get(), py_key.get(), py_value.get()) < 0) {
      throw std::runtime_error("");
    }
  }

  return output;
}
536};

538/** Clean up global python references when the module is finalized. */
539void globals_free(void * /* self */) {
global_domain_map.clear();
BackendNotImplementedError.reset();
identifiers.clear();
543}

545/** Allow GC to break reference cycles between the module and global backends.
*
* NOTE: local state and "thread local globals" can't be visited because we
* can't access locals from another thread. However, since those are only
* set through context managers they should always be unset before module
* cleanup.
*/
552int globals_traverse(PyObject * self, visitproc visit, void * arg) {
for (const auto & kv : global_domain_map) {
  const auto & globals = kv.second;
  PyObject * backend = globals.global.backend.get();
  Py_VISIT(backend)do { if (backend) { int vret = visit(((PyObject*)(backend)), arg
); if (vret) return vret; } } while (0);
  for (const auto & reg : globals.registered) {
    backend = reg.get();
    Py_VISIT(backend)do { if (backend) { int vret = visit(((PyObject*)(backend)), arg
); if (vret) return vret; } } while (0);
  }
}
return 0;
563}

565int globals_clear(PyObject * /* self */) {
global_domain_map.clear();
return 0;
568}

570PyObject * set_global_backend(PyObject * /* self */, PyObject * args) {
PyObject * backend;
int only = false, coerce = false, try_last = false;
if (!PyArg_ParseTuple(args, "O|ppp", &backend, &coerce, &only, &try_last))
  return nullptr;

if (!backend_validate_ua_domain(backend)) {
  return nullptr;
}

const auto res =
    backend_for_each_domain_string(backend, [&](const std::string & domain) {
      backend_options options;
      options.backend = py_ref::ref(backend);
      options.coerce = coerce;
      options.only = only;

      auto & domain_globals = (*current_global_state)[domain];
      domain_globals.global = options;
      domain_globals.try_global_backend_last = try_last;
      return LoopReturn::Continue;
    });

if (res == LoopReturn::Error)
  return nullptr;

Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
597}

599PyObject * register_backend(PyObject * /* self */, PyObject * args) {
PyObject * backend;
if (!PyArg_ParseTuple(args, "O", &backend))
  return nullptr;

if (!backend_validate_ua_domain(backend)) {
  return nullptr;
}

const auto ret =
    backend_for_each_domain_string(backend, [&](const std::string & domain) {
      (*current_global_state)[domain].registered.push_back(
          py_ref::ref(backend));
      return LoopReturn::Continue;
    });
if (ret == LoopReturn::Error)
  return nullptr;

Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
618}

620void clear_single(const std::string & domain, bool registered, bool global) {
auto domain_globals = current_global_state->find(domain);
if (domain_globals == current_global_state->end())
  return;

if (registered && global) {
  current_global_state->erase(domain_globals);
  return;
}

if (registered) {
  domain_globals->second.registered.clear();
}

if (global) {
  domain_globals->second.global.backend.reset();
  domain_globals->second.try_global_backend_last = false;
}
638}

640PyObject * clear_backends(PyObject * /* self */, PyObject * args) {
PyObject * domain = nullptr;
int registered = true, global = false;
if (!PyArg_ParseTuple(args, "O|pp", &domain, &registered, &global))
  return nullptr;

if (domain == Py_None(&_Py_NoneStruct) && registered && global) {
  current_global_state->clear();
  Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
}

auto domain_str = domain_to_string(domain);
clear_single(domain_str, registered, global);
Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
654}

656/** Common functionality of set_backend and skip_backend */
657template <typename T>
658class context_helper {
659public:
using BackendLists = SmallDynamicArray<std::vector<T> *>;
// using BackendLists = std::vector<std::vector<T> *>;
662private:
T new_backend_;
BackendLists backend_lists_;

666public:
const T & get_backend() const { return new_backend_; }

context_helper() {}

bool init(BackendLists && backend_lists, T new_backend) {
  static_assert(std::is_nothrow_move_assignable<BackendLists>::value, "");
  backend_lists_ = std::move(backend_lists);
  new_backend_ = std::move(new_backend);
  return true;
}

bool init(std::vector<T> & backends, T new_backend) {
  try {
    backend_lists_ = BackendLists(1, &backends);
  } catch (std::bad_alloc &) {
    PyErr_NoMemory();
    return false;
  }
  new_backend_ = std::move(new_backend);
  return true;
}

bool enter() {
  auto first = backend_lists_.begin();
  auto last = backend_lists_.end();
  auto cur = first;
  try {
    for (; cur < last; ++cur) {
      (*cur)->push_back(new_backend_);
    }
  } catch (std::bad_alloc &) {
    for (; first < cur; ++first) {
      (*first)->pop_back();
    }
    PyErr_NoMemory();
    return false;
  }
  return true;
}

bool exit() {
  bool success = true;

  for (auto * backends : backend_lists_) {
    if (backends->empty()) {
      PyErr_SetString(
          PyExc_SystemExit, "__exit__ call has no matching __enter__");
      success = false;
      continue;
    }

    if (backends->back() != new_backend_) {
      PyErr_SetString(
          PyExc_RuntimeError,
          "Found invalid context state while in __exit__. "
          "__enter__ and __exit__ may be unmatched");
      success = false;
    }

    backends->pop_back();
  }

  return success;
}
731};


734struct SetBackendContext {
PyObject_HEADPyObject ob_base;

context_helper<backend_options> ctx_;

static void dealloc(SetBackendContext * self) {
  PyObject_GC_UnTrack(self);
  self->~SetBackendContext();
  Py_TYPE(self)(((PyObject*)(self))->ob_type)->tp_free(self);
}

static PyObject * new_(
    PyTypeObject * type, PyObject * args, PyObject * kwargs) {
  auto self = reinterpret_cast<SetBackendContext *>(type->tp_alloc(type, 0));
  if (self == nullptr)
    return nullptr;

  // Placement new
  self = new (self) SetBackendContext;
  return reinterpret_cast<PyObject *>(self);
}

static int init(
    SetBackendContext * self, PyObject * args, PyObject * kwargs) {
  static const char * kwlist[] = {"backend", "coerce", "only", nullptr};
  PyObject * backend = nullptr;
  int coerce = false;
  int only = false;

  if (!PyArg_ParseTupleAndKeywords(
          args, kwargs, "O|pp", (char **)kwlist, &backend, &coerce, &only))
    return -1;

  if (!backend_validate_ua_domain(backend)) {
    return -1;
  }

  auto num_domains = backend_get_num_domains(backend);
  if (num_domains < 0) {
    return -1;
  }

  try {
    decltype(ctx_)::BackendLists backend_lists(num_domains);
    int idx = 0;

    const auto ret = backend_for_each_domain_string(
        backend, [&](const std::string & domain) {
          backend_lists[idx] = &local_domain_map[domain].preferred;
          ++idx;
          return LoopReturn::Continue;
        });

    if (ret == LoopReturn::Error) {
      return -1;
    }

    backend_options opt;
    opt.backend = py_ref::ref(backend);
    opt.coerce = coerce;
    opt.only = only;

    if (!self->ctx_.init(std::move(backend_lists), opt)) {
      return -1;
    }
  } catch (std::bad_alloc &) {
    PyErr_NoMemory();
    return -1;
  }

  return 0;
}

static PyObject * enter__(SetBackendContext * self, PyObject * /* args */) {
  if (!self->ctx_.enter())
    return nullptr;
  Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
}

static PyObject * exit__(SetBackendContext * self, PyObject * /*args*/) {
  if (!self->ctx_.exit())
    return nullptr;
  Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
}

static int traverse(SetBackendContext * self, visitproc visit, void * arg) {
  Py_VISIT(self->ctx_.get_backend().backend.get())do { if (self->ctx_.get_backend().backend.get()) { int vret
 = visit(((PyObject*)(self->ctx_.get_backend().backend.get
())), arg); if (vret) return vret; } } while (0);
  return 0;
}

static PyObject * pickle_(SetBackendContext * self, PyObject * /*args*/) {
  const backend_options & opt = self->ctx_.get_backend();
  return py_make_tuple(opt.backend, py_bool(opt.coerce), py_bool(opt.only))
      .release();
}
829};


832struct SkipBackendContext {
PyObject_HEADPyObject ob_base;

context_helper<py_ref> ctx_;

static void dealloc(SkipBackendContext * self) {
  PyObject_GC_UnTrack(self);
  self->~SkipBackendContext();
  Py_TYPE(self)(((PyObject*)(self))->ob_type)->tp_free(self);
}

static PyObject * new_(
    PyTypeObject * type, PyObject * args, PyObject * kwargs) {
  auto self = reinterpret_cast<SkipBackendContext *>(type->tp_alloc(type, 0));
  if (self == nullptr)
    return nullptr;

  // Placement new
  self = new (self) SkipBackendContext;
  return reinterpret_cast<PyObject *>(self);
}

static int init(
    SkipBackendContext * self, PyObject * args, PyObject * kwargs) {
  static const char * kwlist[] = {"backend", nullptr};
  PyObject * backend;

  if (!PyArg_ParseTupleAndKeywords(
          args, kwargs, "O", (char **)kwlist, &backend))
    return -1;

  if (!backend_validate_ua_domain(backend)) {
    return -1;
  }

  auto num_domains = backend_get_num_domains(backend);
  if (num_domains < 0) {
    return -1;
  }

  try {
    decltype(ctx_)::BackendLists backend_lists(num_domains);
    int idx = 0;

    const auto ret = backend_for_each_domain_string(
        backend, [&](const std::string & domain) {
          backend_lists[idx] = &local_domain_map[domain].skipped;
          ++idx;
          return LoopReturn::Continue;
        });

    if (ret == LoopReturn::Error) {
      return -1;
    }

    if (!self->ctx_.init(std::move(backend_lists), py_ref::ref(backend))) {
      return -1;
    }
  } catch (std::bad_alloc &) {
    PyErr_NoMemory();
    return -1;
  }

  return 0;
}

static PyObject * enter__(SkipBackendContext * self, PyObject * /* args */) {
  if (!self->ctx_.enter())
    return nullptr;
  Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
}

static PyObject * exit__(SkipBackendContext * self, PyObject * /*args*/) {
  if (!self->ctx_.exit())
    return nullptr;
  Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
}

static int traverse(SkipBackendContext * self, visitproc visit, void * arg) {
  Py_VISIT(self->ctx_.get_backend().get())do { if (self->ctx_.get_backend().get()) { int vret = visit
(((PyObject*)(self->ctx_.get_backend().get())), arg); if (
vret) return vret; } } while (0);
  return 0;
}

static PyObject * pickle_(SkipBackendContext * self, PyObject * /*args*/) {
  return py_make_tuple(self->ctx_.get_backend()).release();
}
918};

920const local_backends & get_local_backends(const std::string & domain_key) {
static const local_backends null_local_backends;
auto itr = local_domain_map.find(domain_key);
if (itr == local_domain_map.end()) {
  return null_local_backends;
}
return itr->second;
927}


930const global_backends & get_global_backends(const std::string & domain_key) {
static const global_backends null_global_backends;
const auto & cur_globals = *current_global_state;
auto itr = cur_globals.find(domain_key);
if (itr == cur_globals.end()) {
  return null_global_backends;
}
return itr->second;
938}

940template <typename Callback>
941LoopReturn for_each_backend_in_domain(
  const std::string & domain_key, Callback call) {
const local_backends & locals = get_local_backends(domain_key);

auto & skip = locals.skipped;
auto & pref = locals.preferred;

auto should_skip = [&](PyObject * backend) -> int {
  bool success = true;
  auto it = std::find_if(skip.begin(), skip.end(), [&](const py_ref & be) {
    auto result = PyObject_RichCompareBool(be.get(), backend, Py_EQ2);
    success = (result >= 0);
    return (result != 0);
  });

  if (!success) {
    return -1;
  }

  return (it != skip.end());
};

LoopReturn ret = LoopReturn::Continue;
for (int i = pref.size() - 1; i >= 0; --i) {
  auto options = pref[i];
  int skip_current = should_skip(options.backend.get());
  if (skip_current < 0)
    return LoopReturn::Error;
  if (skip_current)
    continue;

  ret = call(options.backend.get(), options.coerce);
  if (ret != LoopReturn::Continue)
    return ret;

  if (options.only || options.coerce)
    return LoopReturn::Break;
}

auto & globals = get_global_backends(domain_key);
auto try_global_backend = [&] {
  auto & options = globals.global;
  if (!options.backend)
    return LoopReturn::Continue;

  int skip_current = should_skip(options.backend.get());
  if (skip_current < 0)
    return LoopReturn::Error;
  if (skip_current > 0)
    return LoopReturn::Continue;

  return call(options.backend.get(), options.coerce);
};

if (!globals.try_global_backend_last) {
  ret = try_global_backend();
  if (ret != LoopReturn::Continue)
    return ret;

  if (globals.global.only || globals.global.coerce)
    return LoopReturn::Break;
}

for (size_t i = 0; i < globals.registered.size(); ++i) {
  py_ref backend = globals.registered[i];
  int skip_current = should_skip(backend.get());
  if (skip_current < 0)
    return LoopReturn::Error;
  if (skip_current)
    continue;

  ret = call(backend.get(), false);
  if (ret != LoopReturn::Continue)
    return ret;
}

if (!globals.try_global_backend_last) {
  return ret;
}
return try_global_backend();
1021}

1023template <typename Callback>
1024LoopReturn for_each_backend(std::string domain, Callback call) {
do {
  auto ret = for_each_backend_in_domain(domain, call);
  if (ret != LoopReturn::Continue) {
    return ret;
  }

  auto dot_pos = domain.rfind('.');
  if (dot_pos == std::string::npos) {
    return ret;
  }

  domain.resize(dot_pos);
} while (!domain.empty());
return LoopReturn::Continue;
1039}

1041struct py_func_args {
py_ref args, kwargs;
1043};

1045struct Function {
PyObject_HEADPyObject ob_base;
py_ref extractor_, replacer_;  // functions to handle dispatchables
std::string domain_key_;       // associated __ua_domain__ in UTF8
py_ref def_args_, def_kwargs_; // default arguments
py_ref def_impl_;              // default implementation
py_ref dict_;                  // __dict__

PyObject * call(PyObject * args, PyObject * kwargs);

py_func_args replace_dispatchables(
    PyObject * backend, PyObject * args, PyObject * kwargs,
    PyObject * coerce);

py_ref canonicalize_args(PyObject * args);
py_ref canonicalize_kwargs(PyObject * kwargs);

static void dealloc(Function * self) {
  PyObject_GC_UnTrack(self);
  self->~Function();
  Py_TYPE(self)(((PyObject*)(self))->ob_type)->tp_free(self);
}

static PyObject * new_(
    PyTypeObject * type, PyObject * args, PyObject * kwargs) {
  auto self = reinterpret_cast<Function *>(type->tp_alloc(type, 0));
  if (self == nullptr)
    return nullptr;

  // Placement new
  self = new (self) Function;
  return reinterpret_cast<PyObject *>(self);
}

static int init(Function * self, PyObject * args, PyObject * /*kwargs*/) {
  PyObject *extractor, *replacer;
  PyObject * domain;
  PyObject *def_args, *def_kwargs;
  PyObject * def_impl;

  if (!PyArg_ParseTuple(
          args, "OOO!O!O!O", &extractor, &replacer, &PyUnicode_Type, &domain,
          &PyTuple_Type, &def_args, &PyDict_Type, &def_kwargs, &def_impl)) {
    return -1;
  }

  if (!PyCallable_Check(extractor) ||
      (replacer != Py_None(&_Py_NoneStruct) && !PyCallable_Check(replacer))) {
    PyErr_SetString(
        PyExc_TypeError, "Argument extractor and replacer must be callable");
    return -1;
  }

  if (def_impl != Py_None(&_Py_NoneStruct) && !PyCallable_Check(def_impl)) {
    PyErr_SetString(
        PyExc_TypeError, "Default implementation must be Callable or None");
    return -1;
  }

  self->domain_key_ = domain_to_string(domain);
  if (PyErr_Occurred())
    return -1;

  self->extractor_ = py_ref::ref(extractor);
  self->replacer_ = py_ref::ref(replacer);
  self->def_args_ = py_ref::ref(def_args);
  self->def_kwargs_ = py_ref::ref(def_kwargs);
  self->def_impl_ = py_ref::ref(def_impl);

  return 0;
}

static PyObject * repr(Function * self);
static PyObject * descr_get(PyObject * self, PyObject * obj, PyObject * type);
static int traverse(Function * self, visitproc visit, void * arg);
static int clear(Function * self);
static PyObject * get_extractor(Function * self);
static PyObject * get_replacer(Function * self);
static PyObject * get_domain(Function * self);
static PyObject * get_default(Function * self);
1125};


1128bool is_default(PyObject * value, PyObject * def) {
// TODO: richer comparison for builtin types? (if cheap)
return (value == def);
1131}


1134py_ref Function::canonicalize_args(PyObject * args) {
const auto arg_size = PyTuple_GET_SIZE(args)(((PyVarObject*)(((static_cast<void> (0)), (PyTupleObject
 *)(args))))->ob_size);
const auto def_size = PyTuple_GET_SIZE(def_args_.get())(((PyVarObject*)(((static_cast<void> (0)), (PyTupleObject
 *)(def_args_.get()))))->ob_size);

if (arg_size > def_size)
  return py_ref::ref(args);

Py_ssize_t mismatch = 0;
for (Py_ssize_t i = arg_size - 1; i >= 0; --i) {
  auto val = PyTuple_GET_ITEM(args, i)(((static_cast<void> (0)), (PyTupleObject *)(args))->
ob_item[i]);
  auto def = PyTuple_GET_ITEM(def_args_.get(), i)(((static_cast<void> (0)), (PyTupleObject *)(def_args_.
get()))->ob_item[i]);
  if (!is_default(val, def)) {
    mismatch = i + 1;
    break;
  }
}

return py_ref::steal(PyTuple_GetSlice(args, 0, mismatch));
1152}


1155py_ref Function::canonicalize_kwargs(PyObject * kwargs) {
if (kwargs == nullptr)
  return py_ref::steal(PyDict_New());

PyObject *key, *def_value;
Py_ssize_t pos = 0;
while (PyDict_Next(def_kwargs_.get(), &pos, &key, &def_value)) {
  auto val = PyDict_GetItem(kwargs, key);
  if (val && is_default(val, def_value)) {
    PyDict_DelItem(kwargs, key);
  }
}
return py_ref::ref(kwargs);
1168}


1171py_func_args Function::replace_dispatchables(
  PyObject * backend, PyObject * args, PyObject * kwargs, PyObject * coerce) {
auto has_ua_convert = PyObject_HasAttr(backend, identifiers.ua_convert.get());
if (!has_ua_convert) {
  return {py_ref::ref(args), py_ref::ref(kwargs)};
}

auto dispatchables =
    py_ref::steal(PyObject_Call(extractor_.get(), args, kwargs));
if (!dispatchables)
  return {};

PyObject * convert_args[] = {backend, dispatchables.get(), coerce};
auto res = py_ref::steal(Q_PyObject_VectorcallMethod(
    identifiers.ua_convert.get(), convert_args,
    array_size(convert_args) | Q_PY_VECTORCALL_ARGUMENTS_OFFSET((size_t)1 << (8 * sizeof(size_t) - 1)), nullptr));
if (!res) {
  return {};
}

if (res == Py_NotImplemented(&_Py_NotImplementedStruct)) {
  return {std::move(res), nullptr};
}

auto replaced_args = py_ref::steal(PySequence_Tuple(res.get()));
if (!replaced_args)
  return {};

PyObject * replacer_args[] = {nullptr, args, kwargs, replaced_args.get()};
res = py_ref::steal(Q_PyObject_Vectorcall(
    replacer_.get(), &replacer_args[1],
    (array_size(replacer_args) - 1) | Q_PY_VECTORCALL_ARGUMENTS_OFFSET((size_t)1 << (8 * sizeof(size_t) - 1)),
    nullptr));
if (!res)
  return {};

if (!PyTuple_Check(res.get())((((((PyObject*)(res.get()))->ob_type))->tp_flags &
 ((1UL << 26))) != 0) || PyTuple_Size(res.get()) != 2) {
  PyErr_SetString(
      PyExc_TypeError,
      "Argument replacer must return a 2-tuple (args, kwargs)");
  return {};
}

auto new_args = py_ref::ref(PyTuple_GET_ITEM(res.get(), 0)(((static_cast<void> (0)), (PyTupleObject *)(res.get())
)->ob_item[0]));
auto new_kwargs = py_ref::ref(PyTuple_GET_ITEM(res.get(), 1)(((static_cast<void> (0)), (PyTupleObject *)(res.get())
)->ob_item[1]));

new_kwargs = canonicalize_kwargs(new_kwargs.get());

if (!PyTuple_Check(new_args.get())((((((PyObject*)(new_args.get()))->ob_type))->tp_flags &
 ((1UL << 26))) != 0) || !PyDict_Check(new_kwargs.get())((((((PyObject*)(new_kwargs.get()))->ob_type))->tp_flags
 & ((1UL << 29))) != 0)) {
  PyErr_SetString(PyExc_ValueError, "Invalid return from argument_replacer");
  return {};
}

return {std::move(new_args), std::move(new_kwargs)};
1225}


1228PyObject * Function_call(Function * self, PyObject * args, PyObject * kwargs) {
return self->call(args, kwargs);
1230}

1232class py_errinf {
py_ref type_, value_, traceback_;

1235public:
static py_errinf fetch() {
  PyObject *type, *value, *traceback;
  PyErr_Fetch(&type, &value, &traceback);
  py_errinf err;
  err.set(type, value, traceback);
  return err;
}

py_ref get_exception() {
  normalize();
  return value_;
}

1249private:
void set(PyObject * type, PyObject * value, PyObject * traceback) {
  type_ = py_ref::steal(type);
  value_ = py_ref::steal(value);
  traceback_ = py_ref::steal(traceback);
}

void normalize() {
  auto type = type_.release();
  auto value = value_.release();
  auto traceback = value_.release();
  PyErr_NormalizeException(&type, &value, &traceback);
  if (traceback) {
    PyException_SetTraceback(value, traceback);
  }
  set(type, value, traceback);
}
1266};


1269PyObject * Function::call(PyObject * args_, PyObject * kwargs_) {
auto args = canonicalize_args(args_);
auto kwargs = canonicalize_kwargs(kwargs_);

py_ref result;
std::vector<std::pair<py_ref, py_errinf>> errors;


auto ret =
    for_each_backend(domain_key_, [&, this](PyObject * backend, bool coerce) {
      auto new_args = replace_dispatchables(
          backend, args.get(), kwargs.get(), coerce ? Py_True((PyObject *) &_Py_TrueStruct) : Py_False((PyObject *) &_Py_FalseStruct));
      if (new_args.args == Py_NotImplemented(&_Py_NotImplementedStruct))
        return LoopReturn::Continue;
      if (new_args.args == nullptr)
        return LoopReturn::Error;

      PyObject * args[] = {backend, reinterpret_cast<PyObject *>(this),
                           new_args.args.get(), new_args.kwargs.get()};
      result = py_ref::steal(Q_PyObject_VectorcallMethod(
          identifiers.ua_function.get(), args,
          array_size(args) | Q_PY_VECTORCALL_ARGUMENTS_OFFSET((size_t)1 << (8 * sizeof(size_t) - 1)), nullptr));

      // raise BackendNotImplemeted is equivalent to return NotImplemented
      if (!result &&
          PyErr_ExceptionMatches(BackendNotImplementedError.get())) {
        errors.push_back({py_ref::ref(backend), py_errinf::fetch()});
        result = py_ref::ref(Py_NotImplemented(&_Py_NotImplementedStruct));
      }

      // Try the default with this backend
      if (result == Py_NotImplemented(&_Py_NotImplementedStruct) && def_impl_ != Py_None(&_Py_NoneStruct)) {
        backend_options opt;
        opt.backend = py_ref::ref(backend);
        opt.coerce = coerce;
        opt.only = true;
        context_helper<backend_options> ctx;
        try {
          if (!ctx.init(
                  local_domain_map[domain_key_].preferred, std::move(opt)))
            return LoopReturn::Error;
        } catch (std::bad_alloc &) {
          PyErr_NoMemory();
          return LoopReturn::Error;
        }

        if (!ctx.enter())
          return LoopReturn::Error;

        result = py_ref::steal(PyObject_Call(
            def_impl_.get(), new_args.args.get(), new_args.kwargs.get()));

        if (PyErr_Occurred() &&
            PyErr_ExceptionMatches(BackendNotImplementedError.get())) {
          errors.push_back({py_ref::ref(backend), py_errinf::fetch()});
          result = py_ref::ref(Py_NotImplemented(&_Py_NotImplementedStruct));
        }

        if (!ctx.exit())
          return LoopReturn::Error;
      }

      if (!result)
        return LoopReturn::Error;

      if (result == Py_NotImplemented(&_Py_NotImplementedStruct))
        return LoopReturn::Continue;

      return LoopReturn::Break; // Backend called successfully
    });

if (ret == LoopReturn::Error)
  return nullptr;

if (result && result != Py_NotImplemented(&_Py_NotImplementedStruct))
  return result.release();

// Last resort, try calling default implementation directly
// Only call if no backend was marked only or coerce
if (ret == LoopReturn::Continue && def_impl_ != Py_None(&_Py_NoneStruct)) {
  result =
      py_ref::steal(PyObject_Call(def_impl_.get(), args.get(), kwargs.get()));
  if (!result) {
    if (!PyErr_ExceptionMatches(BackendNotImplementedError.get()))
      return nullptr;

    errors.push_back({py_ref::ref(Py_None(&_Py_NoneStruct)), py_errinf::fetch()});
    result = py_ref::ref(Py_NotImplemented(&_Py_NotImplementedStruct));
  } else if (result != Py_NotImplemented(&_Py_NotImplementedStruct))
    return result.release();
}


// All backends and defaults failed, construct the exception
auto exception_tuple = py_ref::steal(PyTuple_New(errors.size() + 1));
PyTuple_SET_ITEM(PyTuple_SetItem(exception_tuple.get(), 0, PyUnicode_FromString
( "No selected backends had an implementation for this function."
))
    exception_tuple.get(), 0,PyTuple_SetItem(exception_tuple.get(), 0, PyUnicode_FromString
( "No selected backends had an implementation for this function."
))
    PyUnicode_FromString(PyTuple_SetItem(exception_tuple.get(), 0, PyUnicode_FromString
( "No selected backends had an implementation for this function."
))
        "No selected backends had an implementation for this function."))PyTuple_SetItem(exception_tuple.get(), 0, PyUnicode_FromString
( "No selected backends had an implementation for this function."
));
for (size_t i = 0; i < errors.size(); ++i) {
  auto pair =
      py_make_tuple(errors[i].first, errors[i].second.get_exception());
  if (!pair)
    return nullptr;

  PyTuple_SET_ITEM(exception_tuple.get(), i + 1, pair.release())PyTuple_SetItem(exception_tuple.get(), i + 1, pair.release());
}
PyErr_SetObject(BackendNotImplementedError.get(), exception_tuple.get());
return nullptr;
1378}


1381PyObject * Function::repr(Function * self) {
if (self->dict_)
  if (auto name = PyDict_GetItemString(self->dict_.get(), "__name__"))
    return PyUnicode_FromFormat("<uarray multimethod '%S'>", name);

return PyUnicode_FromString("<uarray multimethod>");
1387}


1390/** Implements the descriptor protocol to allow binding to class instances */
1391PyObject * Function::descr_get(
  PyObject * self, PyObject * obj, PyObject * type) {
if (!obj) {
  Py_INCREF(self)_Py_INCREF(((PyObject*)(self)));
  return self;
}

return PyMethod_New(self, obj);
1399}


1402/** Make members visible to the garbage collector */
1403int Function::traverse(Function * self, visitproc visit, void * arg) {
Py_VISIT(self->extractor_.get())do { if (self->extractor_.get()) { int vret = visit(((PyObject
*)(self->extractor_.get())), arg); if (vret) return vret; }
 } while (0);
Py_VISIT(self->replacer_.get())do { if (self->replacer_.get()) { int vret = visit(((PyObject
*)(self->replacer_.get())), arg); if (vret) return vret; }
 } while (0);
Py_VISIT(self->def_args_.get())do { if (self->def_args_.get()) { int vret = visit(((PyObject
*)(self->def_args_.get())), arg); if (vret) return vret; }
 } while (0);
Py_VISIT(self->def_kwargs_.get())do { if (self->def_kwargs_.get()) { int vret = visit(((PyObject
*)(self->def_kwargs_.get())), arg); if (vret) return vret;
 } } while (0);
Py_VISIT(self->def_impl_.get())do { if (self->def_impl_.get()) { int vret = visit(((PyObject
*)(self->def_impl_.get())), arg); if (vret) return vret; }
 } while (0);
Py_VISIT(self->dict_.get())do { if (self->dict_.get()) { int vret = visit(((PyObject*
)(self->dict_.get())), arg); if (vret) return vret; } } while
 (0);
return 0;
1411}


1414/** Break reference cycles when being GCed */
1415int Function::clear(Function * self) {
self->extractor_.reset();
self->replacer_.reset();
self->def_args_.reset();
self->def_kwargs_.reset();
self->def_impl_.reset();
self->dict_.reset();
return 0;
1423}

1425PyObject * Function::get_extractor(Function * self) {
Py_INCREF(self->extractor_.get())_Py_INCREF(((PyObject*)(self->extractor_.get())));
return self->extractor_.get();
1428}

1430PyObject * Function::get_replacer(Function * self) {
Py_INCREF(self->replacer_.get())_Py_INCREF(((PyObject*)(self->replacer_.get())));
return self->replacer_.get();
1433}

1435PyObject * Function::get_default(Function * self) {
Py_INCREF(self->def_impl_.get())_Py_INCREF(((PyObject*)(self->def_impl_.get())));
return self->def_impl_.get();
1438}

1440PyObject * Function::get_domain(Function * self) {
return PyUnicode_FromStringAndSize(
    self->domain_key_.c_str(), self->domain_key_.size());
1443}


1446PyMethodDef BackendState_Methods[] = {
  {"_pickle", (PyCFunction)BackendState::pickle_, METH_NOARGS0x0004, nullptr},
  {"_unpickle", (PyCFunction)BackendState::unpickle_,
   METH_VARARGS0x0001 | METH_CLASS0x0010, nullptr},
  {NULL__null} /* Sentinel */
1451};

1453PyTypeObject BackendStateType = {
  PyVarObject_HEAD_INIT(NULL, 0){ { 1, __null }, 0 },     /* boilerplate */
  "uarray._BackendState",            /* tp_name */
  sizeof(BackendState),              /* tp_basicsize */
  0,                                 /* tp_itemsize */
  (destructor)BackendState::dealloc, /* tp_dealloc */
  0,                                 /* tp_print */
  0,                                 /* tp_getattr */
  0,                                 /* tp_setattr */
  0,                                 /* tp_reserved */
  0,                                 /* tp_repr */
  0,                                 /* tp_as_number */
  0,                                 /* tp_as_sequence */
  0,                                 /* tp_as_mapping */
  0,                                 /* tp_hash  */
  0,                                 /* tp_call */
  0,                                 /* tp_str */
  0,                                 /* tp_getattro */
  0,                                 /* tp_setattro */
  0,                                 /* tp_as_buffer */
  Py_TPFLAGS_DEFAULT( 0 | (1UL << 18) | 0),                /* tp_flags */
  0,                                 /* tp_doc */
  0,                                 /* tp_traverse */
  0,                                 /* tp_clear */
  0,                                 /* tp_richcompare */
  0,                                 /* tp_weaklistoffset */
  0,                                 /* tp_iter */
  0,                                 /* tp_iternext */
  BackendState_Methods,              /* tp_methods */
  0,                                 /* tp_members */
  0,                                 /* tp_getset */
  0,                                 /* tp_base */
  0,                                 /* tp_dict */
  0,                                 /* tp_descr_get */
  0,                                 /* tp_descr_set */
  0,                                 /* tp_dictoffset */
  0,                                 /* tp_init */
  0,                                 /* tp_alloc */
  BackendState::new_,                /* tp_new */
1492};

1494PyObject * get_state(PyObject * /* self */, PyObject * /* args */) {
py_ref ref = py_ref::steal(Q_PyObject_Vectorcall(
    reinterpret_cast<PyObject *>(&BackendStateType), nullptr, 0, nullptr));
BackendState * output = reinterpret_cast<BackendState *>(ref.get());

output->locals = local_domain_map;
output->use_thread_local_globals =
    (current_global_state != &global_domain_map);
output->globals = *current_global_state;

return ref.release();
1505}

1507PyObject * set_state(PyObject * /* self */, PyObject * args) {
PyObject * arg;
int reset_allowed = false;
if (!PyArg_ParseTuple(args, "O|p", &arg, &reset_allowed))
  return nullptr;

if (!PyObject_IsInstance(
        arg, reinterpret_cast<PyObject *>(&BackendStateType))) {
  PyErr_SetString(
      PyExc_TypeError, "state must be a uarray._BackendState object.");
  return nullptr;
}

BackendState * state = reinterpret_cast<BackendState *>(arg);
local_domain_map = state->locals;
bool use_thread_local_globals =
    (!reset_allowed) || state->use_thread_local_globals;
current_global_state =
    use_thread_local_globals ? &thread_local_domain_map : &global_domain_map;

if (use_thread_local_globals)
  thread_local_domain_map = state->globals;
else
  thread_local_domain_map.clear();


Py_RETURN_NONEreturn _Py_INCREF(((PyObject*)((&_Py_NoneStruct)))), (&
_Py_NoneStruct);
1534}

1536PyObject * determine_backend(PyObject * /*self*/, PyObject * args) {
PyObject *domain_object, *dispatchables;
int coerce;
if (!PyArg_ParseTuple(
        args, "OOp:determine_backend", &domain_object, &dispatchables,
        &coerce))
  return nullptr;

auto domain = domain_to_string(domain_object);
if (domain.empty())
  return nullptr;

auto dispatchables_tuple = py_ref::steal(PySequence_Tuple(dispatchables));
if (!dispatchables_tuple)
  return nullptr;

py_ref selected_backend;
auto result = for_each_backend_in_domain(
    domain, [&](PyObject * backend, bool coerce_backend) {
      auto has_ua_convert =
          PyObject_HasAttr(backend, identifiers.ua_convert.get());

      if (!has_ua_convert) {
        // If no __ua_convert__, assume it won't accept the type
        return LoopReturn::Continue;
      }

      PyObject * convert_args[] = {backend, dispatchables_tuple.get(),
                                   (coerce && coerce_backend) ? Py_True((PyObject *) &_Py_TrueStruct)
                                                              : Py_False((PyObject *) &_Py_FalseStruct)};

      auto res = py_ref::steal(Q_PyObject_VectorcallMethod(
          identifiers.ua_convert.get(), convert_args,
          array_size(convert_args) | Q_PY_VECTORCALL_ARGUMENTS_OFFSET((size_t)1 << (8 * sizeof(size_t) - 1)),
          nullptr));
      if (!res) {
        return LoopReturn::Error;
      }

      if (res == Py_NotImplemented(&_Py_NotImplementedStruct)) {
        return LoopReturn::Continue;
      }

      // __ua_convert__ succeeded, so select this backend
      selected_backend = py_ref::ref(backend);
      return LoopReturn::Break;
    });

if (result != LoopReturn::Continue)
  return selected_backend.release();

// All backends failed, raise an error
PyErr_SetString(
    BackendNotImplementedError.get(),
    "No backends could accept input of this type.");
return nullptr;
1592}


1595// getset takes mutable char * in python < 3.7
1596static char dict__[] = "__dict__";
1597static char arg_extractor[] = "arg_extractor";
1598static char arg_replacer[] = "arg_replacer";
1599static char default_[] = "default";
1600static char domain[] = "domain";
1601PyGetSetDef Function_getset[] = {
  {dict__, PyObject_GenericGetDict, PyObject_GenericSetDict},
  {arg_extractor, (getter)Function::get_extractor, NULL__null},
  {arg_replacer, (getter)Function::get_replacer, NULL__null},
  {default_, (getter)Function::get_default, NULL__null},
  {domain, (getter)Function::get_domain, NULL__null},
  {NULL__null} /* Sentinel */
1608};

1610PyTypeObject FunctionType = {
  PyVarObject_HEAD_INIT(NULL, 0){ { 1, __null }, 0 }, /* boilerplate */
  /* tp_name= */ "uarray._Function",
  /* tp_basicsize= */ sizeof(Function),
  /* tp_itemsize= */ 0,
  /* tp_dealloc= */ (destructor)Function::dealloc,
  /* tp_print= */ 0,
  /* tp_getattr= */ 0,
  /* tp_setattr= */ 0,
  /* tp_reserved= */ 0,
  /* tp_repr= */ (reprfunc)Function::repr,
  /* tp_as_number= */ 0,
  /* tp_as_sequence= */ 0,
  /* tp_as_mapping= */ 0,
  /* tp_hash= */ 0,
  /* tp_call= */ (ternaryfunc)Function_call,
  /* tp_str= */ 0,
  /* tp_getattro= */ PyObject_GenericGetAttr,
  /* tp_setattro= */ PyObject_GenericSetAttr,
  /* tp_as_buffer= */ 0,
  /* tp_flags= */
  (Py_TPFLAGS_DEFAULT( 0 | (1UL << 18) | 0) | Py_TPFLAGS_HAVE_GC(1UL << 14) | Q_Py_TPFLAGS_METHOD_DESCRIPTOR(1UL << 17)),
  /* tp_doc= */ 0,
  /* tp_traverse= */ (traverseproc)Function::traverse,
  /* tp_clear= */ (inquiry)Function::clear,
  /* tp_richcompare= */ 0,
  /* tp_weaklistoffset= */ 0,
  /* tp_iter= */ 0,
  /* tp_iternext= */ 0,
  /* tp_methods= */ 0,
  /* tp_members= */ 0,
  /* tp_getset= */ Function_getset,
  /* tp_base= */ 0,
  /* tp_dict= */ 0,
  /* tp_descr_get= */ Function::descr_get,
  /* tp_descr_set= */ 0,
  /* tp_dictoffset= */ offsetof(Function, dict_)__builtin_offsetof(Function, dict_),
  /* tp_init= */ (initproc)Function::init,
  /* tp_alloc= */ 0,
  /* tp_new= */ Function::new_,
1650};


1653PyMethodDef SetBackendContext_Methods[] = {
  {"__enter__", (PyCFunction)SetBackendContext::enter__, METH_NOARGS0x0004,
   nullptr},
  {"__exit__", (PyCFunction)SetBackendContext::exit__, METH_VARARGS0x0001, nullptr},
  {"_pickle", (PyCFunction)SetBackendContext::pickle_, METH_NOARGS0x0004, nullptr},
  {NULL__null} /* Sentinel */
1659};

1661PyTypeObject SetBackendContextType = {
  PyVarObject_HEAD_INIT(NULL, 0){ { 1, __null }, 0 },             /* boilerplate */
  "uarray._SetBackendContext",               /* tp_name */
  sizeof(SetBackendContext),                 /* tp_basicsize */
  0,                                         /* tp_itemsize */
  (destructor)SetBackendContext::dealloc,    /* tp_dealloc */
  0,                                         /* tp_print */
  0,                                         /* tp_getattr */
  0,                                         /* tp_setattr */
  0,                                         /* tp_reserved */
  0,                                         /* tp_repr */
  0,                                         /* tp_as_number */
  0,                                         /* tp_as_sequence */
  0,                                         /* tp_as_mapping */
  0,                                         /* tp_hash  */
  0,                                         /* tp_call */
  0,                                         /* tp_str */
  0,                                         /* tp_getattro */
  0,                                         /* tp_setattro */
  0,                                         /* tp_as_buffer */
  (Py_TPFLAGS_DEFAULT( 0 | (1UL << 18) | 0) | Py_TPFLAGS_HAVE_GC(1UL << 14)), /* tp_flags */
  0,                                         /* tp_doc */
  (traverseproc)SetBackendContext::traverse, /* tp_traverse */
  0,                                         /* tp_clear */
  0,                                         /* tp_richcompare */
  0,                                         /* tp_weaklistoffset */
  0,                                         /* tp_iter */
  0,                                         /* tp_iternext */
  SetBackendContext_Methods,                 /* tp_methods */
  0,                                         /* tp_members */
  0,                                         /* tp_getset */
  0,                                         /* tp_base */
  0,                                         /* tp_dict */
  0,                                         /* tp_descr_get */
  0,                                         /* tp_descr_set */
  0,                                         /* tp_dictoffset */
  (initproc)SetBackendContext::init,         /* tp_init */
  0,                                         /* tp_alloc */
  SetBackendContext::new_,                   /* tp_new */
1700};


1703PyMethodDef SkipBackendContext_Methods[] = {
  {"__enter__", (PyCFunction)SkipBackendContext::enter__, METH_NOARGS0x0004,
   nullptr},
  {"__exit__", (PyCFunction)SkipBackendContext::exit__, METH_VARARGS0x0001,
   nullptr},
  {"_pickle", (PyCFunction)SkipBackendContext::pickle_, METH_NOARGS0x0004, nullptr},
  {NULL__null} /* Sentinel */
1710};

1712PyTypeObject SkipBackendContextType = {
  PyVarObject_HEAD_INIT(NULL, 0){ { 1, __null }, 0 },              /* boilerplate */
  "uarray._SkipBackendContext",               /* tp_name */
  sizeof(SkipBackendContext),                 /* tp_basicsize */
  0,                                          /* tp_itemsize */
  (destructor)SkipBackendContext::dealloc,    /* tp_dealloc */
  0,                                          /* tp_print */
  0,                                          /* tp_getattr */
  0,                                          /* tp_setattr */
  0,                                          /* tp_reserved */
  0,                                          /* tp_repr */
  0,                                          /* tp_as_number */
  0,                                          /* tp_as_sequence */
  0,                                          /* tp_as_mapping */
  0,                                          /* tp_hash  */
  0,                                          /* tp_call */
  0,                                          /* tp_str */
  0,                                          /* tp_getattro */
  0,                                          /* tp_setattro */
  0,                                          /* tp_as_buffer */
  (Py_TPFLAGS_DEFAULT( 0 | (1UL << 18) | 0) | Py_TPFLAGS_HAVE_GC(1UL << 14)),  /* tp_flags */
  0,                                          /* tp_doc */
  (traverseproc)SkipBackendContext::traverse, /* tp_traverse */
  0,                                          /* tp_clear */
  0,                                          /* tp_richcompare */
  0,                                          /* tp_weaklistoffset */
  0,                                          /* tp_iter */
  0,                                          /* tp_iternext */
  SkipBackendContext_Methods,                 /* tp_methods */
  0,                                          /* tp_members */
  0,                                          /* tp_getset */
  0,                                          /* tp_base */
  0,                                          /* tp_dict */
  0,                                          /* tp_descr_get */
  0,                                          /* tp_descr_set */
  0,                                          /* tp_dictoffset */
  (initproc)SkipBackendContext::init,         /* tp_init */
  0,                                          /* tp_alloc */
  SkipBackendContext::new_,                   /* tp_new */
1751};


1754PyMethodDef method_defs[] = {
  {"set_global_backend", set_global_backend, METH_VARARGS0x0001, nullptr},
  {"register_backend", register_backend, METH_VARARGS0x0001, nullptr},
  {"clear_backends", clear_backends, METH_VARARGS0x0001, nullptr},
  {"determine_backend", determine_backend, METH_VARARGS0x0001, nullptr},
  {"get_state", get_state, METH_NOARGS0x0004, nullptr},
  {"set_state", set_state, METH_VARARGS0x0001, nullptr},
  {NULL__null} /* Sentinel */
1762};

1764PyModuleDef uarray_module = {PyModuleDef_HEAD_INIT{ { 1, __null }, __null, 0, __null, },
                           /* m_name= */ "uarray._uarray",
                           /* m_doc= */ nullptr,
                           /* m_size= */ -1,
                           /* m_methods= */ method_defs,
                           /* m_slots= */ nullptr,
                           /* m_traverse= */ globals_traverse,
                           /* m_clear= */ globals_clear,
                           /* m_free= */ globals_free};

1774} // namespace

1776#if defined(WIN32) || defined(_WIN32)
1777#  define MODULE_EXPORT__attribute__((visibility("default"))) __declspec(dllexport)
1778#else
1779#  define MODULE_EXPORT__attribute__((visibility("default"))) __attribute__((visibility("default")))
1780#endif

1782extern "C" MODULE_EXPORT__attribute__((visibility("default"))) PyObject * PyInit__uarray(void) {

auto m = py_ref::steal(PyModule_Create(&uarray_module)PyModule_Create2(&uarray_module, 1013));
if (!m)
  return nullptr;

if (PyType_Ready(&FunctionType) < 0)
  return nullptr;
Py_INCREF(&FunctionType)_Py_INCREF(((PyObject*)(&FunctionType)));
PyModule_AddObject(m.get(), "_Function", (PyObject *)&FunctionType);

if (PyType_Ready(&SetBackendContextType) < 0)
  return nullptr;
Py_INCREF(&SetBackendContextType)_Py_INCREF(((PyObject*)(&SetBackendContextType)));
PyModule_AddObject(
    m.get(), "_SetBackendContext", (PyObject *)&SetBackendContextType);

if (PyType_Ready(&SkipBackendContextType) < 0)
  return nullptr;
Py_INCREF(&SkipBackendContextType)_Py_INCREF(((PyObject*)(&SkipBackendContextType)));
PyModule_AddObject(
    m.get(), "_SkipBackendContext", (PyObject *)&SkipBackendContextType);

if (PyType_Ready(&BackendStateType) < 0)
  return nullptr;
Py_INCREF(&BackendStateType)_Py_INCREF(((PyObject*)(&BackendStateType)));
PyModule_AddObject(m.get(), "_BackendState", (PyObject *)&BackendStateType);

BackendNotImplementedError = py_ref::steal(PyErr_NewExceptionWithDoc(
    "uarray.BackendNotImplementedError",
    "An exception that is thrown when no compatible"
    " backend is found for a method.",
    PyExc_NotImplementedError, nullptr));
if (!BackendNotImplementedError)
  return nullptr;
Py_INCREF(BackendNotImplementedError.get())_Py_INCREF(((PyObject*)(BackendNotImplementedError.get())));
PyModule_AddObject(
    m.get(), "BackendNotImplementedError", BackendNotImplementedError.get());

if (!identifiers.init())
  return nullptr;

return m.release();
1825}

←

/opt/pyrefcon/lib/pyrefcon/models/models/PyObject_GetIter.model

1#ifndef PyObject_GetIter
2struct _object;
3typedef struct _object PyObject;
4PyObject* clang_analyzer_PyObject_New_Reference();
5PyObject* PyObject_GetIter(PyObject *o) {
6  return clang_analyzer_PyObject_New_Reference();
5
←
Setting reference count to 1→
7}
8#else
9#warning "API PyObject_GetIter is defined as a macro."
10#endif