revert struct reference pointer sizes to i8 to ensure that compiler does not optimize

pythonbpf/codegen.py

@@ -39,7 +39,7 @@ def finalize_module(original_str):
 
 def bpf_passthrough_gen(module):
     i32_ty = ir.IntType(32)
-    ptr_ty = ir.PointerType(ir.IntType(64))
+    ptr_ty = ir.PointerType(ir.IntType(8))
     fnty = ir.FunctionType(ptr_ty, [i32_ty, ptr_ty])
 
     # Declare the intrinsic

pythonbpf/debuginfo/debug_info_generator.py

@@ -184,3 +184,83 @@ class DebugInfoGenerator:
             "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})
+
+    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)
+
+    def create_subprogram(
+        self, name: str, subroutine_type: Any, retained_nodes: List[Any]
+    ) -> Any:
+        """
+        Create a DISubprogram for a function.
+
+        Args:
+            name: Function name
+            subroutine_type: DISubroutineType for the function signature
+            retained_nodes: List of DILocalVariable nodes for function parameters/variables
+
+        Returns:
+            DISubprogram metadata
+        """
+        return self.module.add_debug_info(
+            "DISubprogram",
+            {
+                "name": name,
+                "scope": self.module._file_metadata,
+                "file": self.module._file_metadata,
+                "type": subroutine_type,
+                # TODO: the following flags do not exist at the moment in our dwarf constants file. We need to add them.
+                # "flags": dc.DW_FLAG_Prototyped | dc.DW_FLAG_AllCallsDescribed,
+                # "spFlags": dc.DW_SPFLAG_Definition | dc.DW_SPFLAG_Optimized,
+                "unit": self.module._debug_compile_unit,
+                "retainedNodes": retained_nodes,
+            },
+            is_distinct=True,
+        )

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 +15,58 @@ 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
+    annotation = leading_argument.annotation
-    print(leading_argument.arg, leading_argument.annotation.id)
+    if func_node.returns is None:
-    context_debug_info = VmlinuxHandlerRegistry.get_struct_debug_info(
+        # TODO: should check if this logic is consistent with function return type handling elsewhere
-        name=leading_argument.annotation.id
+        return_type = ctypes.c_int64()
-    )
+    elif hasattr(func_node.returns, "id"):
-    print(context_debug_info)
+        return_type = func_node.returns.id
-    pass
+        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
+        )
+        context_local_variable = generator.create_local_variable_debug_info(
+            leading_argument_name, 1, pointer_to_context_debug_info
+        )
+        retained_nodes = [context_local_variable]
+        print("function name", func_node.name)
+        subprogram_debug_info = generator.create_subprogram(
+            func_node.name, subroutine_type, retained_nodes
+        )
+        generator.add_scope_to_local_variable(
+            context_local_variable, subprogram_debug_info
+        )
+        func.set_metadata("dbg", subprogram_debug_info)
+
+    else:
+        logger.error(f"Invalid annotation type for argument '{leading_argument_name}'")

pythonbpf/vmlinux_parser/vmlinux_exports_handler.py

@@ -97,7 +97,7 @@ class VmlinuxHandler:
             globvar_ir, field_data = self.get_field_type(
                 python_type.__name__, field_name
             )
-            builder.function.args[0].type = ir.PointerType(ir.IntType(64))
+            builder.function.args[0].type = ir.PointerType(ir.IntType(8))
             print(builder.function.args[0])
             field_ptr = self.load_ctx_field(
                 builder, builder.function.args[0], globvar_ir
@@ -125,19 +125,18 @@ class VmlinuxHandler:
         # Load the offset value
         offset = builder.load(offset_global)
 
-        # # Ensure ctx_arg is treated as i8* (byte pointer)
+        # Ensure ctx_arg is treated as i8* (byte pointer)
-        # # i8_type = ir.IntType(8)
+        i8_ptr_type = ir.PointerType()
-        # i8_ptr_type = ir.PointerType()
 
         # Cast ctx_arg to i8* if it isn't already
-        # if str(ctx_arg.type) != str(i8_ptr_type):
+        if str(ctx_arg.type) != str(i8_ptr_type):
-        #     ctx_i8_ptr = builder.bitcast(ctx_arg, i8_ptr_type)
+            ctx_i8_ptr = builder.bitcast(ctx_arg, i8_ptr_type)
-        # else:
+        else:
-        #     ctx_i8_ptr = ctx_arg
+            ctx_i8_ptr = ctx_arg
 
         # GEP with explicit type - this is the key fix
         field_ptr = builder.gep(
-            ctx_arg,
+            ctx_i8_ptr,
             [offset],
             inbounds=False,
         )
@@ -151,8 +150,8 @@ class VmlinuxHandler:
                 raise KeyError
         except (KeyError, AttributeError):
             passthrough_type = ir.FunctionType(
-                ir.PointerType(),
+                i8_ptr_type,
-                [ir.IntType(32), ir.PointerType()],
+                [ir.IntType(32), i8_ptr_type],
             )
             passthrough_fn = ir.Function(
                 module,

tests/failing_tests/vmlinux/struct_field_access.py

@@ -4,7 +4,7 @@ from pythonbpf import bpf, section, bpfglobal, compile_to_ir
 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