create debug info to subroutine type

Author: varun-r-mallya

pythonbpf/debuginfo/debug_info_generator.py

@@ -184,3 +184,20 @@ def create_global_var_debug_info(
             "DIGlobalVariableExpression",
             {"var": global_var, "expr": self.module.add_debug_info("DIExpression", {})},
         )
+
+    def get_int64_type(self):
+        return self.get_basic_type("long", 64, dc.DW_ATE_signed)
+
+    def create_subroutine_type(self, return_type, param_types):
+        """
+        Create a DISubroutineType given return type and list of parameter types.
+        Equivalent to: !DISubroutineType(types: !{ret, args...})
+        """
+        type_array = [return_type]
+        if isinstance(param_types, (list, tuple)):
+            type_array.extend(param_types)
+        else:
+            type_array.append(param_types)
+        return self.module.add_debug_info("DISubroutineType", {"types": type_array})
+
+

pythonbpf/functions/function_debug_info.py

@@ -1,9 +1,12 @@
 import ast
 
 import llvmlite.ir as ir
-
+import logging
 from pythonbpf.debuginfo import DebugInfoGenerator
 from pythonbpf.expr import VmlinuxHandlerRegistry
+import ctypes
+
+logger = logging.getLogger(__name__)
 
 
 def generate_function_debug_info(
@@ -12,10 +15,42 @@ def generate_function_debug_info(
     generator = DebugInfoGenerator(module)
     leading_argument = func_node.args.args[0]
     leading_argument_name = leading_argument.arg
-    # TODO: add ctypes handling as well here
-    print(leading_argument.arg, leading_argument.annotation.id)
-    context_debug_info = VmlinuxHandlerRegistry.get_struct_debug_info(
-        name=leading_argument.annotation.id
-    )
-    print(context_debug_info)
-    pass
+    annotation = leading_argument.annotation
+    if func_node.returns is None:
+        # TODO: should check if this logic is consistent with function return type handling elsewhere
+        return_type = ctypes.c_int64()
+    elif hasattr(func_node.returns, "id"):
+        return_type = func_node.returns.id
+        if return_type == "c_int32":
+            return_type = generator.get_int32_type()
+        elif return_type == "c_int64":
+            return_type = generator.get_int64_type()
+        elif return_type == "c_uint32":
+            return_type = generator.get_uint32_type()
+        elif return_type == "c_uint64":
+            return_type = generator.get_uint64_type()
+        else:
+            logger.warning(
+                "Return type should be int32, int64, uint32 or uint64 only. Falling back to int64"
+            )
+            return_type = generator.get_int64_type()
+    else:
+        return_type = ctypes.c_int64()
+    # context processing
+    if annotation is None:
+        logger.warning("Type of context of function not found.")
+        return
+    if hasattr(annotation, "id"):
+        ctype_name = annotation.id
+        if ctype_name == "c_void_p":
+            return
+        elif ctype_name.startswith("ctypes"):
+            raise SyntaxError(
+                "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)
+    else:
+        logger.error(f"Invalid annotation type for argument '{leading_argument_name}'")

tests/failing_tests/vmlinux/struct_field_access.py

@@ -4,7 +4,7 @@
 from pythonbpf import compile  # noqa: F401
 from vmlinux import TASK_COMM_LEN  # noqa: F401
 from vmlinux import struct_trace_event_raw_sys_enter  # noqa: F401
-from ctypes import c_int64, c_void_p  # noqa: F401
+from ctypes import c_int64, c_int32, c_void_p  # noqa: F401
 
 
 # from vmlinux import struct_uinput_device
@@ -13,10 +13,10 @@
 
 @bpf
 @section("tracepoint/syscalls/sys_enter_execve")
-def hello_world(ctx: struct_trace_event_raw_sys_enter) -> c_int64:
+def hello_world(ctx: struct_trace_event_raw_sys_enter) -> c_int32:
     b = ctx.id
     print(f"This is context field {b}")
-    return c_int64(0)
+    return c_int32(0)
 
 
 @bpf