Fixes breakpoint on function name.

Author: Diptorup Deb

numba_dpex/core/debuginfo.py

@@ -0,0 +1,43 @@
+# SPDX-FileCopyrightText: 2020 - 2024 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""Implements a custom debug metadata generator class for numba-dpex kernels.
+"""
+
+from numba.core import debuginfo
+
+
+class DIBuilder(debuginfo.DIBuilder):
+    """Overrides Numba's default DIBuilder with numba-dpex-specific customizations."""
+
+    # pylint: disable=too-many-arguments
+    def mark_subprogram(self, function, qualname, argnames, argtypes, line):
+        """Sets DW_AT_name and DW_AT_linkagename tags for a kernel decorated function.
+
+        Numba generates a unique name for every function it compiles, but in
+        upstream Numba the unique name is not used as the "qualified" name of
+        the function. The behavior leads to a bug discovered in Numba-dpex when
+        a compiled function uses closure variables.
+        Refer (https://github.com/IntelPython/numba-dpex/issues/898).
+        To resolve the issue numba-dpex uses the unique_name as the qualified
+        name. Refer to
+        :class:`numba_dpex.core.passes.passes.QualNameDisambiguationLowering`.
+        However, doing so breaks setting GDB breakpoints based on function
+        name as the function name is no longer what is in the source, but what
+        is the unique name generated by Numba. To fix it, numba-dpex uses a
+        modified DISubprogram metadata generator. The name (DW_AT_name) tag is
+        set to the base function name, discarding the unique qualifier and
+        linkagename is set to an empty string.
+        """
+        name = qualname[0 : qualname.find("$")]  # noqa: E203
+        argmap = dict(zip(argnames, argtypes))
+
+        di_subp = self._add_subprogram(
+            name=name,
+            linkagename="",
+            line=line,
+            function=function,
+            argmap=argmap,
+        )
+        function.set_metadata("dbg", di_subp)

numba_dpex/kernel_api_impl/spirv/target.py

@@ -21,6 +21,7 @@
 from numba.core.typing import cmathdecl, enumdecl
 
 from numba_dpex.core.datamodel.models import _init_kernel_data_model_manager
+from numba_dpex.core.debuginfo import DIBuilder as DpexDIbuilder
 from numba_dpex.core.types import IntEnumLiteral
 from numba_dpex.core.typing import dpnpdecl
 from numba_dpex.core.utils import itanium_mangler
@@ -135,6 +136,7 @@ class SPIRVTargetContext(BaseContext):
 
     implement_powi_as_math_call = True
     allow_dynamic_globals = True
+    DIBuilder = DpexDIbuilder
 
     def __init__(self, typingctx, target=SPIRV_TARGET_NAME):
         super().__init__(typingctx, target)