one recursion issue solved

Author: varun-r-mallya

pythonbpf/vmlinux_parser/class_handler.py

@@ -15,7 +15,20 @@ def get_module_symbols(module_name: str):
 
 
 # Recursive function that gets all the dependent classes and adds them to handler
-def process_vmlinux_class(node, llvm_module, handler: DependencyHandler):
+def process_vmlinux_class(node, llvm_module, handler: DependencyHandler, processing_stack=None):
+    """
+    Recursively process vmlinux classes and their dependencies.
+
+    Args:
+        node: The class/type to process
+        llvm_module: The LLVM module context
+        handler: DependencyHandler to track all nodes
+        processing_stack: Set of currently processing nodes to detect cycles
+    """
+    # Initialize processing stack on first call
+    if processing_stack is None:
+        processing_stack = set()
+
     symbols_in_module, imported_module = get_module_symbols("vmlinux")
 
     # Handle both node objects and type objects
@@ -28,80 +41,120 @@ def process_vmlinux_class(node, llvm_module, handler: DependencyHandler):
 
     if current_symbol_name not in symbols_in_module:
         raise ImportError(f"{current_symbol_name} not present in module vmlinux")
+
+    # Check if we're already processing this node (circular dependency)
+    if current_symbol_name in processing_stack:
+        logger.debug(f"Circular dependency detected for {current_symbol_name}, skipping")
+        return True
+
+    # Check if already processed
+    if handler.has_node(current_symbol_name):
+        existing_node = handler.get_node(current_symbol_name)
+        # If the node exists and is ready, we're done
+        if existing_node and existing_node.is_ready:
+            logger.info(f"Node {current_symbol_name} already processed and ready")
+            return True
+
     logger.info(f"Resolving vmlinux class {current_symbol_name}")
     logger.debug(
         f"Current handler state: {handler.is_ready} readiness and {handler.get_all_nodes()} all nodes"
     )
-    field_table = {}  # should contain the field and it's type.
 
-    # Get the class object from the module
-    class_obj = getattr(imported_module, current_symbol_name)
+    # Add to processing stack to detect cycles
+    processing_stack.add(current_symbol_name)
 
-    # Below, I've written a general structure that gets class-info
-    # everytime, no matter the format in which it is present
+    try:
+        field_table = {}  # should contain the field and it's type.
 
-    # Inspect the class fields
-    # Assuming class_obj has fields stored in some standard way
-    # If it's a ctypes-like structure with _fields_
-    if hasattr(class_obj, "_fields_"):
-        for field_name, field_type in class_obj._fields_:
-            field_table[field_name] = field_type
+        # Get the class object from the module
+        class_obj = getattr(imported_module, current_symbol_name)
 
-    # If it's using __annotations__
-    elif hasattr(class_obj, "__annotations__"):
-        for field_name, field_type in class_obj.__annotations__.items():
-            field_table[field_name] = field_type
+        # Inspect the class fields
+        if hasattr(class_obj, "_fields_"):
+            for field_name, field_type in class_obj._fields_:
+                field_table[field_name] = field_type
+        elif hasattr(class_obj, "__annotations__"):
+            for field_name, field_type in class_obj.__annotations__.items():
+                field_table[field_name] = field_type
+        else:
+            raise TypeError("Could not get required class and definition")
 
-    else:
-        raise TypeError("Could not get required class and definition")
+        logger.debug(f"Extracted fields for {current_symbol_name}: {field_table}")
 
-    logger.debug(f"Extracted fields for {current_symbol_name}: {field_table}")
-    if handler.has_node(current_symbol_name):
-        logger.info("Extraction pruned due to already available field")
-        return True
-    else:
-        new_dep_node = DependencyNode(name=current_symbol_name)
-        handler.add_node(new_dep_node)
+        # Create or get the node
+        if handler.has_node(current_symbol_name):
+            new_dep_node = handler.get_node(current_symbol_name)
+        else:
+            new_dep_node = DependencyNode(name=current_symbol_name)
+            handler.add_node(new_dep_node)
+
+        # Process each field
         for elem_name, elem_type in field_table.items():
             module_name = getattr(elem_type, "__module__", None)
+
             if module_name == ctypes.__name__:
+                # Simple ctypes - mark as ready immediately
                 new_dep_node.add_field(elem_name, elem_type, ready=True)
+
             elif module_name == "vmlinux":
+                # Complex vmlinux type - needs recursive processing
                 new_dep_node.add_field(elem_name, elem_type, ready=False)
-                print("elem_name:", elem_name, "elem_type:", elem_type)
-                # currently fails when a non-normal type appears which is basically everytime
+                logger.debug(f"Processing vmlinux field: {elem_name}, type: {elem_type}")
+
                 identify_ctypes_type(elem_name, elem_type, new_dep_node)
+
+                # Determine the actual symbol to process
                 symbol_name = (
                     elem_type.__name__
                     if hasattr(elem_type, "__name__")
                     else str(elem_type)
                 )
                 vmlinux_symbol = None
+
+                # Handle pointers/arrays to other types
                 if hasattr(elem_type, "_type_"):
                     containing_module_name = getattr(
                         (elem_type._type_), "__module__", None
                     )
                     if containing_module_name == ctypes.__name__:
+                        # Pointer/Array to ctypes - mark as ready
                         new_dep_node.set_field_ready(elem_name, True)
                         continue
                     elif containing_module_name == "vmlinux":
+                        # Pointer/Array to vmlinux type
                         symbol_name = (
                             (elem_type._type_).__name__
                             if hasattr((elem_type._type_), "__name__")
                             else str(elem_type._type_)
                         )
+
+                        # Self-referential check
+                        if symbol_name == current_symbol_name:
+                            logger.debug(f"Self-referential field {elem_name} in {current_symbol_name}")
+                            # For pointers to self, we can mark as ready since the type is being defined
+                            new_dep_node.set_field_ready(elem_name, True)
+                            continue
+
                         vmlinux_symbol = getattr(imported_module, symbol_name)
                 else:
+                    # Direct vmlinux type (not pointer/array)
                     vmlinux_symbol = getattr(imported_module, symbol_name)
-                if process_vmlinux_class(vmlinux_symbol, llvm_module, handler):
-                    new_dep_node.set_field_ready(elem_name, True)
+
+                # Recursively process the dependency
+                if vmlinux_symbol is not None:
+                    if process_vmlinux_class(vmlinux_symbol, llvm_module, handler, processing_stack):
+                        new_dep_node.set_field_ready(elem_name, True)
             else:
                 raise ValueError(
                     f"{elem_name} with type {elem_type} not supported in recursive resolver"
                 )
-        logger.info(f"added node: {current_symbol_name}")
 
-    return True
+        logger.info(f"Successfully processed node: {current_symbol_name}")
+        return True
+
+    finally:
+        # Remove from processing stack when done
+        processing_stack.discard(current_symbol_name)
 
 
 def identify_ctypes_type(elem_name, elem_type, new_dep_node: DependencyNode):

tests/failing_tests/xdp_pass.py

@@ -1,9 +1,9 @@
 from pythonbpf import bpf, map, section, bpfglobal, compile, compile_to_ir
 from pythonbpf.maps import HashMap
 from pythonbpf.helper import XDP_PASS
-from vmlinux import struct_xdp_md
-# from vmlinux import struct_ring_buffer_per_cpu  # noqa: F401
+from vmlinux import struct_ring_buffer_per_cpu  # noqa: F401
 from vmlinux import struct_xdp_buff  # noqa: F401
+from vmlinux import struct_xdp_md
 from ctypes import c_int64
 
 # Instructions to how to run this program