Disallow LocalAccessor arguments to RangeType kernels

Author: Diptorup Deb

numba_dpex/experimental/launcher.py

@@ -25,6 +25,7 @@
     ItemType,
     NdItemType,
 )
+from numba_dpex.core.types.kernel_api.local_accessor import LocalAccessorType
 from numba_dpex.core.utils import kernel_launcher as kl
 from numba_dpex.dpctl_iface import libsyclinterface_bindings as sycl
 from numba_dpex.dpctl_iface.wrappers import wrap_event_reference
@@ -42,6 +43,23 @@ class _LLRange(NamedTuple):
     local_range_extents: list
 
 
+def _has_a_local_accessor_argument(args):
+    """Checks if there exists at least one LocalAccessorType object in the
+    input tuple.
+
+    Args:
+        args (_type_): A tuple of numba.core.Type objects
+
+    Returns:
+        bool : True if at least one LocalAccessorType object was found,
+            otherwise False.
+    """
+    for arg in args:
+        if isinstance(arg, LocalAccessorType):
+            return True
+    return False
+
+
 def _wrap_event_reference_tuple(ctx, builder, event1, event2):
     """Creates tuple data model from two event data models, so it can be
     boxed to Python."""
@@ -153,6 +171,18 @@ def _submit_kernel(  # pylint: disable=too-many-arguments
             DeprecationWarning,
         )
 
+    # Validate local accessor arguments are passed only to a kernel that is
+    # launched with an NdRange index space. Reference section 4.7.6.11. of the
+    # SYCL 2020 specification: A local_accessor must not be used in a SYCL
+    # kernel function that is invoked via single_task or via the simple form of
+    # parallel_for that takes a range parameter.
+    if _has_a_local_accessor_argument(ty_kernel_args_tuple) and isinstance(
+        ty_index_space, RangeType
+    ):
+        raise TypeError(
+            "A RangeType kernel cannot have a LocalAccessor argument"
+        )
+
     # ty_kernel_fn is type specific to exact function, so we can get function
     # directly from type and compile it. Thats why we don't need to get it in
     # codegen

numba_dpex/tests/experimental/kernel_api_overloads/spv_overloads/test_local_accessors.py

@@ -5,6 +5,7 @@
 
 import dpnp
 import pytest
+from numba.core.errors import TypingError
 
 import numba_dpex as dpex
 import numba_dpex.experimental as dpex_exp
@@ -21,23 +22,24 @@
 )
 
 
-@pytest.mark.parametrize("supported_dtype", list_of_supported_dtypes)
-def test_local_accessor(supported_dtype):
-    """A test for passing a LocalAccessor object as a kernel argument."""
+@dpex_exp.kernel
+def _kernel(nd_item: NdItem, a, slm):
+    i = nd_item.get_global_linear_id()
+    j = nd_item.get_local_linear_id()
 
-    @dpex_exp.kernel
-    def _kernel(nd_item: NdItem, a, slm):
-        i = nd_item.get_global_linear_id()
-        j = nd_item.get_local_linear_id()
+    slm[j] = 0
+    group_barrier(nd_item.get_group(), MemoryScope.WORK_GROUP)
 
-        slm[j] = 0
+    for m in range(100):
+        slm[j] += i * m
         group_barrier(nd_item.get_group(), MemoryScope.WORK_GROUP)
 
-        for m in range(100):
-            slm[j] += i * m
-            group_barrier(nd_item.get_group(), MemoryScope.WORK_GROUP)
+    a[i] = slm[j]
 
-        a[i] = slm[j]
+
+@pytest.mark.parametrize("supported_dtype", list_of_supported_dtypes)
+def test_local_accessor(supported_dtype):
+    """A test for passing a LocalAccessor object as a kernel argument."""
 
     N = 32
     a = dpnp.empty(N, dtype=supported_dtype)
@@ -52,3 +54,18 @@ def _kernel(nd_item: NdItem, a, slm):
 
     for idx in range(N):
         assert a[idx] == 4950 * idx
+
+
+def test_local_accessor_argument_to_range_kernel():
+    """Checks if an exception is raised when passing a local accessor to a
+    RangeType kernel.
+    """
+    N = 32
+    a = dpnp.empty(N)
+    slm = LocalAccessor((32 * 64), dtype=a.dtype)
+
+    # Passing a local_accessor to a RangeType kernel should raise an exception.
+    # A TypeError is raised if NUMBA_CAPTURED_ERROR=new_style and a
+    # numba.TypingError is raised if NUMBA_CAPTURED_ERROR=old_style
+    with pytest.raises((TypeError, TypingError)):
+        dpex_exp.call_kernel(_kernel, dpex.Range(N), a, slm)