Merge pull request #9539 from sklam/misc/revert_retarget

Revert PR #6870 `numba.core.retarget`

docs/source/developer/repomap.rst

@@ -100,8 +100,6 @@ Dispatching
   for different type signatures.
 - :ghfile:`numba/_dispatcher.cpp` - C++ dispatcher implementation (for speed on
   common data types)
-- :ghfile:`numba/core/retarget.py` - Support for dispatcher objects to switch
-  target via a specific with-context.
 
 
 Compiler Pipeline

docs/upcoming_changes/9539.expired.rst

@@ -0,0 +1,7 @@
+Removal of ``numba.core.retarget``
+----------------------------------
+
+The experimental features implemented in ``numba.core.retarget`` have been
+removed. These features were primarily used in numba-dpex, but that project has
+replaced its use of ``numba.core.retarget`` with a preference for
+*target extension API*.

numba/_dispatcher.cpp

@@ -910,35 +910,6 @@ find_named_args(Dispatcher *self, PyObject **pargs, PyObject **pkws)
     return 0;
 }
 
-
-/*
- * Management of thread-local
- */
-
-#ifdef _MSC_VER
-#define THREAD_LOCAL(ty) __declspec(thread) ty
-#else
-/* Non-standard C99 extension that's understood by gcc and clang */
-#define THREAD_LOCAL(ty) __thread ty
-#endif
-
-static THREAD_LOCAL(bool) use_tls_target_stack;
-
-
-struct raii_use_tls_target_stack {
-    bool old_setting;
-
-    raii_use_tls_target_stack(bool new_setting)
-        : old_setting(use_tls_target_stack)
-    {
-        use_tls_target_stack = new_setting;
-    }
-
-    ~raii_use_tls_target_stack() {
-        use_tls_target_stack = old_setting;
-    }
-};
-
 static PyObject*
 Dispatcher_call(Dispatcher *self, PyObject *args, PyObject *kws)
 {
@@ -952,19 +923,6 @@ Dispatcher_call(Dispatcher *self, PyObject *args, PyObject *kws)
     PyThreadState *ts = PyThreadState_Get();
     PyObject *locals = NULL;
 
-    // Check TLS target stack
-    if (use_tls_target_stack) {
-        raii_use_tls_target_stack turn_off(false);
-        PyObject * meth_call_tls_target;
-        meth_call_tls_target = PyObject_GetAttrString((PyObject*)self,
-                                                      "_call_tls_target");
-        if (!meth_call_tls_target) return NULL;
-        // Transfer control to self._call_tls_target
-        retval = PyObject_Call(meth_call_tls_target, args, kws);
-        Py_DECREF(meth_call_tls_target);
-        return retval;
-    }
-
     /* If compilation is enabled, ensure that an exact match is found and if
      * not compile one */
     int exact_match_required = self->can_compile ? 1 : self->exact_match_required;
@@ -1291,26 +1249,10 @@ static PyObject *compute_fingerprint(PyObject *self, PyObject *args)
     return typeof_compute_fingerprint(val);
 }
 
-static PyObject *set_use_tls_target_stack(PyObject *self, PyObject *args)
-{
-    int val;
-    if (!PyArg_ParseTuple(args, "p", &val))
-        return NULL;
-    bool old = use_tls_target_stack;
-    use_tls_target_stack = val;
-    // return the old value
-    if (old) {
-        Py_RETURN_TRUE;
-    } else {
-        Py_RETURN_FALSE;
-    }
-}
-
 static PyMethodDef ext_methods[] = {
 #define declmethod(func) { #func , ( PyCFunction )func , METH_VARARGS , NULL }
     declmethod(typeof_init),
     declmethod(compute_fingerprint),
-    declmethod(set_use_tls_target_stack),
     { NULL },
 #undef declmethod
 };

numba/core/compiler.py

@@ -138,13 +138,6 @@ class Flags(TargetConfig):
         default=cpu.InlineOptions("never"),
         doc="TODO",
     )
-    # Defines a new target option for tracking the "target backend".
-    # This will be the XYZ in @jit(_target=XYZ).
-    target_backend = Option(
-        type=str,
-        default="cpu", # if not set, default to CPU
-        doc="backend"
-    )
 
     dbg_extend_lifetimes = Option(
         type=bool,

numba/core/cpu.py

@@ -282,8 +282,6 @@ def get_ufunc_info(self, ufunc_key):
     "error_model",
     "inline",
     "forceinline",
-    # Add "target_backend" as a accepted option for the CPU in @jit(...)
-    "target_backend",
     "_dbg_extend_lifetimes",
     "_dbg_optnone",
 )
@@ -320,9 +318,6 @@ def finalize(self, flags, options):
 
         flags.inherit_if_not_set("error_model", default="python")
 
-        # Add "target_backend" as a option that inherits from the caller
-        flags.inherit_if_not_set("target_backend")
-
         flags.inherit_if_not_set("forceinline")
 
         if flags.forceinline:

numba/core/decorators.py

@@ -148,10 +148,6 @@ def bar(x, y):
         assert type(nopython) is bool, "nopython option must be a bool"
     if nopython is True and forceobj:
         raise ValueError("Only one of 'nopython' or 'forceobj' can be True.")
-
-    if "_target" in options:
-        # Set the "target_backend" option if "_target" is defined.
-        options['target_backend'] = options['_target']
     target = options.pop('_target', 'cpu')
 
     if nopython is False:

numba/core/dispatcher.py

@@ -21,54 +21,9 @@
 from numba.core.bytecode import get_code_object
 from numba.core.caching import NullCache, FunctionCache
 from numba.core import entrypoints
-from numba.core.retarget import BaseRetarget
 import numba.core.event as ev
 
 
-class _RetargetStack(utils.ThreadLocalStack, stack_name="retarget"):
-    def push(self, state):
-        super().push(state)
-        _dispatcher.set_use_tls_target_stack(len(self) > 0)
-
-    def pop(self):
-        super().pop()
-        _dispatcher.set_use_tls_target_stack(len(self) > 0)
-
-
-class TargetConfigurationStack:
-    """The target configuration stack.
-
-    Uses the BORG pattern and stores states in threadlocal storage.
-
-    WARNING: features associated with this class are experimental. The API
-    may change without notice.
-    """
-
-    def __init__(self):
-        self._stack = _RetargetStack()
-
-    def get(self):
-        """Get the current target from the top of the stack.
-
-        May raise IndexError if the stack is empty. Users should check the size
-        of the stack beforehand.
-        """
-        return self._stack.top()
-
-    def __len__(self):
-        """Size of the stack
-        """
-        return len(self._stack)
-
-    @classmethod
-    def switch_target(cls, retarget: BaseRetarget):
-        """Returns a contextmanager that pushes a new retarget handler,
-        an instance of `numba.core.retarget.BaseRetarget`, onto the
-        target-config stack for the duration of the context-manager.
-        """
-        return cls()._stack.enter(retarget)
-
-
 class OmittedArg(object):
     """
     A placeholder for omitted arguments with a default value.
@@ -838,9 +793,6 @@ def __init__(self, py_func, locals={}, targetoptions={},
         self._type = types.Dispatcher(self)
         self.typingctx.insert_global(self, self._type)
 
-        # Remember target restriction
-        self._required_target_backend = targetoptions.get('target_backend')
-
     def dump(self, tab=''):
         print(f'{tab}DUMP {type(self).__name__}[{self.py_func.__name__}'
               f', type code={self._type._code}]')
@@ -905,10 +857,6 @@ def _rebuild(cls, uuid, py_func, locals, targetoptions,
         return self
 
     def compile(self, sig):
-        disp = self._get_dispatcher_for_current_target()
-        if disp is not self:
-            return disp.compile(sig)
-
         with ExitStack() as scope:
             cres = None
 
@@ -1049,34 +997,6 @@ def get_function_type(self):
             cres = tuple(self.overloads.values())[0]
             return types.FunctionType(cres.signature)
 
-    def _get_retarget_dispatcher(self):
-        """Returns a dispatcher for the retarget request.
-        """
-        # Check TLS target configuration
-        tc = TargetConfigurationStack()
-        retarget = tc.get()
-        retarget.check_compatible(self)
-        disp = retarget.retarget(self)
-        return disp
-
-    def _get_dispatcher_for_current_target(self):
-        """Returns a dispatcher for the current target registered in
-        `TargetConfigurationStack`. `self` is returned if no target is
-        specified.
-        """
-        tc = TargetConfigurationStack()
-        if tc:
-            return self._get_retarget_dispatcher()
-        else:
-            return self
-
-    def _call_tls_target(self, *args, **kwargs):
-        """This is called when the C dispatcher logic sees a retarget request.
-        """
-        disp = self._get_retarget_dispatcher()
-        # Call the new dispatcher
-        return disp(*args, **kwargs)
-
 
 class LiftedCode(serialize.ReduceMixin, _MemoMixin, _DispatcherBase):
     """

numba/core/options.py

@@ -91,8 +91,6 @@ class DefaultOptions:
     inline = _mapping("inline")
     forceinline = _mapping("forceinline")
 
-    target_backend = _mapping("target_backend")
-
     _dbg_extend_lifetimes = _mapping("dbg_extend_lifetimes")
     _dbg_optnone = _mapping("dbg_optnone")