Overload implementation for dpnp.empty.

    - Removes the numba_dpex/core/dpnp_ndarray modules
    - Adds an arrayobj submodule to numba_dpex/dpnp_iface
    - Implements boxing and unboxing for dpnp.ndarrays using
      _dpexrt_python extension.
    - Adds an overload for dpnp.empty to dono_iface/arrayobj.

Author: Diptorup Deb

numba_dpex/core/__init__.py

@@ -4,6 +4,5 @@
 
 
 from .datamodel import *
-from .dpnp_ndarray import dpnp_empty
 from .types import *
 from .typing import *

numba_dpex/core/dpnp_ndarray/__init__.py

@@ -3,13 +3,123 @@
 # SPDX-License-Identifier: Apache-2.0
 
 
+from numba.core import cgutils
+from numba.core.errors import NumbaNotImplementedError
+from numba.core.pythonapi import NativeValue, PythonAPI, box, unbox
+from numba.np import numpy_support
+
+from numba_dpex.core.exceptions import UnreachableError
+from numba_dpex.core.runtime import context as dpexrt
+
 from .usm_ndarray_type import USMNdArray
 
 
 class DpnpNdArray(USMNdArray):
     """
     The Numba type to represent an dpnp.ndarray. The type has the same
-    structure as USMNdArray used to represnet dpctl.tensor.usm_ndarray.
+    structure as USMNdArray used to represent dpctl.tensor.usm_ndarray.
+    """
+
+    @property
+    def is_internal(self):
+        return True
+
+
+# --------------- Boxing/Unboxing logic for dpnp.ndarray ----------------------#
+
+
+@unbox(DpnpNdArray)
+def unbox_dpnp_nd_array(typ, obj, c):
+    """Converts a dpnp.ndarray object to a Numba internal array structure.
+
+    Args:
+        typ : The Numba type of the PyObject
+        obj : The actual PyObject to be unboxed
+        c :
+
+    Returns:
+        _type_: _description_
     """
+    # Reusing the numba.core.base.BaseContext's make_array function to get a
+    # struct allocated. The same struct is used for numpy.ndarray
+    # and dpnp.ndarray. It is possible to do so, as the extra information
+    # specific to dpnp.ndarray such as sycl_queue is inferred statically and
+    # stored as part of the DpnpNdArray type.
+
+    # --------------- Original Numba comment from @ubox(types.Array)
+    #
+    # This is necessary because unbox_buffer() does not work on some
+    # dtypes, e.g. datetime64 and timedelta64.
+    # TODO check matching dtype.
+    #      currently, mismatching dtype will still work and causes
+    #      potential memory corruption
+    #
+    # --------------- End of Numba comment from @ubox(types.Array)
+    nativearycls = c.context.make_array(typ)
+    nativeary = nativearycls(c.context, c.builder)
+    aryptr = nativeary._getpointer()
+
+    ptr = c.builder.bitcast(aryptr, c.pyapi.voidptr)
+    # FIXME : We need to check if Numba_RT as well as DPEX RT are enabled.
+    if c.context.enable_nrt:
+        dpexrtCtx = dpexrt.DpexRTContext(c.context)
+        errcode = dpexrtCtx.arraystruct_from_python(c.pyapi, obj, ptr)
+    else:
+        raise UnreachableError
+
+    # TODO: here we have minimal typechecking by the itemsize.
+    #       need to do better
+    try:
+        expected_itemsize = numpy_support.as_dtype(typ.dtype).itemsize
+    except NumbaNotImplementedError:
+        # Don't check types that can't be `as_dtype()`-ed
+        itemsize_mismatch = cgutils.false_bit
+    else:
+        expected_itemsize = nativeary.itemsize.type(expected_itemsize)
+        itemsize_mismatch = c.builder.icmp_unsigned(
+            "!=",
+            nativeary.itemsize,
+            expected_itemsize,
+        )
+
+    failed = c.builder.or_(
+        cgutils.is_not_null(c.builder, errcode),
+        itemsize_mismatch,
+    )
+    # Handle error
+    with c.builder.if_then(failed, likely=False):
+        c.pyapi.err_set_string(
+            "PyExc_TypeError",
+            "can't unbox array from PyObject into "
+            "native value.  The object maybe of a "
+            "different type",
+        )
+    return NativeValue(c.builder.load(aryptr), is_error=failed)
+
+
+@box(DpnpNdArray)
+def box_array(typ, val, c):
+    if c.context.enable_nrt:
+        np_dtype = numpy_support.as_dtype(typ.dtype)
+        dtypeptr = c.env_manager.read_const(c.env_manager.add_const(np_dtype))
+        dpexrtCtx = dpexrt.DpexRTContext(c.context)
+        newary = dpexrtCtx.usm_ndarray_to_python_acqref(
+            c.pyapi, typ, val, dtypeptr
+        )
+
+        if not newary:
+            c.pyapi.err_set_string(
+                "PyExc_TypeError",
+                "could not box native array into a dpnp.ndarray PyObject.",
+            )
+
+        # Steals NRT ref
+        # Refer:
+        #   numba.core.base.nrt -> numba.core.runtime.context -> decref
+        #   The `NRT_decref` function is generated directly as LLVM IR inside
+        #   numba.core.runtime.nrtdynmod.py
+        c.context.nrt.decref(c.builder, typ, val)
 
-    pass
+        return newary
+    else:
+        raise UnreachableError

numba_dpex/core/dpnp_ndarray/dpnp_empty.py

@@ -2,6 +2,8 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+from . import arrayobj
+
 
 def ensure_dpnp(name):
     try:
@@ -24,4 +26,5 @@ def _init_dpnp():
 
 _init_dpnp()
 
+
 DEBUG = None