add scope field separately to subroutine type remove circular dependency

Author: varun-r-mallya

pythonbpf/debuginfo/debug_info_generator.py

@@ -200,4 +200,37 @@ def create_subroutine_type(self, return_type, param_types):
             type_array.append(param_types)
         return self.module.add_debug_info("DISubroutineType", {"types": type_array})
 
+    def create_local_variable_debug_info(
+        self, name: str, arg: int, var_type: Any
+    ) -> Any:
+        """
+        Create debug info for a local variable (DILocalVariable) without scope.
+        Example:
+        !DILocalVariable(name: "ctx", arg: 1, file: !3, line: 20, type: !7)
+        """
+        return self.module.add_debug_info(
+            "DILocalVariable",
+            {
+                "name": name,
+                "arg": arg,
+                "file": self.module._file_metadata,
+                "type": var_type,
+            },
+        )
 
+    def add_scope_to_local_variable(self, local_variable_debug_info, scope_value):
+        """
+        Add scope information to an existing local variable debug info object.
+        """
+        #TODO: this is a workaround a flaw in the debug info generation. Fix this if possible in the future.
+        # We should not be touching llvmlite's internals like this.
+        if hasattr(local_variable_debug_info, 'operands'):
+            # LLVM metadata operands is a tuple, so we need to rebuild it
+            existing_operands = local_variable_debug_info.operands
+
+            # Convert tuple to list, add scope, convert back to tuple
+            operands_list = list(existing_operands)
+            operands_list.append(('scope', scope_value))
+
+            # Reassign the new tuple
+            local_variable_debug_info.operands = tuple(operands_list)

pythonbpf/functions/function_debug_info.py

@@ -49,8 +49,18 @@ def generate_function_debug_info(
                 "The first argument should always be a pointer to a struct or a void pointer"
             )
         context_debug_info = VmlinuxHandlerRegistry.get_struct_debug_info(annotation.id)
-        pointer_to_context_debug_info = generator.create_pointer_type(context_debug_info, 64)
-        subroutine_type = generator.create_subroutine_type(return_type, pointer_to_context_debug_info)
-        print(subroutine_type)
+        pointer_to_context_debug_info = generator.create_pointer_type(
+            context_debug_info, 64
+        )
+        subroutine_type = generator.create_subroutine_type(
+            return_type, pointer_to_context_debug_info
+        )
+        context_local_variable = generator.create_local_variable_debug_info(
+            leading_argument_name, 1, pointer_to_context_debug_info
+        )
+
+        # following is just a test.
+        generator.add_scope_to_local_variable(context_local_variable, module._file_metadata)
+        print(context_local_variable)
     else:
         logger.error(f"Invalid annotation type for argument '{leading_argument_name}'")