Use named args for eval_expr call in handle_return

Fix failing tests in tests/

.pre-commit-config.yaml

@@ -21,7 +21,7 @@ ci:
 repos:
 # Standard hooks
 - repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: v4.6.0
+  rev: v6.0.0
   hooks:
   - id: check-added-large-files
   - id: check-case-conflict
@@ -36,7 +36,7 @@ repos:
   - id: trailing-whitespace
 
 - repo: https://github.com/astral-sh/ruff-pre-commit
-  rev: "v0.4.2"
+  rev: "v0.13.2"
   hooks:
     - id: ruff
       args: ["--fix", "--show-fixes"]
@@ -45,7 +45,7 @@ repos:
 
 # Checking static types
 - repo: https://github.com/pre-commit/mirrors-mypy
-  rev: "v1.10.0"
+  rev: "v1.18.2"
   hooks:
     - id: mypy
       exclude: ^(tests)|^(examples)

TODO.md

@@ -1,7 +1,6 @@
 ## Short term
 
 - Implement enough functionality to port the BCC tutorial examples in PythonBPF
-- Static Typing
 - Add all maps
 - XDP support in pylibbpf
 - ringbuf support

examples/clone-matplotlib.ipynb

@@ -12,7 +12,7 @@
     "from pythonbpf import bpf, map, section, bpfglobal, BPF\n",
     "from pythonbpf.helper import pid\n",
     "from pythonbpf.maps import HashMap\n",
-    "from pylibbpf import *\n",
+    "from pylibbpf import BpfMap\n",
     "from ctypes import c_void_p, c_int64, c_uint64, c_int32\n",
     "import matplotlib.pyplot as plt"
    ]

examples/sys_sync.py

@@ -21,17 +21,17 @@ def last() -> HashMap:
 @section("tracepoint/syscalls/sys_enter_sync")
 def do_trace(ctx: c_void_p) -> c_int64:
     key = 0
-    tsp = last().lookup(key)
+    tsp = last.lookup(key)
     if tsp:
         kt = ktime()
         delta = kt - tsp
         if delta < 1000000000:
             time_ms = delta // 1000000
             print(f"sync called within last second, last {time_ms} ms ago")
-        last().delete(key)
+        last.delete(key)
     else:
         kt = ktime()
-        last().update(key, kt)
+        last.update(key, kt)
     return c_int64(0)
 
 

pythonbpf/binary_ops.py

@@ -8,68 +8,65 @@ logger: Logger = logging.getLogger(__name__)
 
 def recursive_dereferencer(var, builder):
     """dereference until primitive type comes out"""
-    if var.type == ir.PointerType(ir.PointerType(ir.IntType(64))):
+    # TODO: Not worrying about stack overflow for now
+    logger.info(f"Dereferencing {var}, type is {var.type}")
+    if isinstance(var.type, ir.PointerType):
         a = builder.load(var)
         return recursive_dereferencer(a, builder)
-    elif var.type == ir.PointerType(ir.IntType(64)):
+    elif isinstance(var.type, ir.IntType):
-        a = builder.load(var)
-        return recursive_dereferencer(a, builder)
-    elif var.type == ir.IntType(64):
         return var
     else:
         raise TypeError(f"Unsupported type for dereferencing: {var.type}")
 
 
-def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab, func):
+def get_operand_value(operand, builder, local_sym_tab):
-    logger.info(f"module {module}")
+    """Extract the value from an operand, handling variables and constants."""
-    left = rval.left
+    if isinstance(operand, ast.Name):
-    right = rval.right
+        if operand.id in local_sym_tab:
+            return recursive_dereferencer(local_sym_tab[operand.id].var, builder)
+        raise ValueError(f"Undefined variable: {operand.id}")
+    elif isinstance(operand, ast.Constant):
+        if isinstance(operand.value, int):
+            return ir.Constant(ir.IntType(64), operand.value)
+        raise TypeError(f"Unsupported constant type: {type(operand.value)}")
+    elif isinstance(operand, ast.BinOp):
+        return handle_binary_op_impl(operand, builder, local_sym_tab)
+    raise TypeError(f"Unsupported operand type: {type(operand)}")
+
+
+def handle_binary_op_impl(rval, builder, local_sym_tab):
     op = rval.op
-
+    left = get_operand_value(rval.left, builder, local_sym_tab)
-    # Handle left operand
+    right = get_operand_value(rval.right, builder, local_sym_tab)
-    if isinstance(left, ast.Name):
-        if left.id in local_sym_tab:
-            left = recursive_dereferencer(local_sym_tab[left.id].var, builder)
-        else:
-            raise SyntaxError(f"Undefined variable: {left.id}")
-    elif isinstance(left, ast.Constant):
-        left = ir.Constant(ir.IntType(64), left.value)
-    else:
-        raise SyntaxError("Unsupported left operand type")
-
-    if isinstance(right, ast.Name):
-        if right.id in local_sym_tab:
-            right = recursive_dereferencer(local_sym_tab[right.id].var, builder)
-        else:
-            raise SyntaxError(f"Undefined variable: {right.id}")
-    elif isinstance(right, ast.Constant):
-        right = ir.Constant(ir.IntType(64), right.value)
-    else:
-        raise SyntaxError("Unsupported right operand type")
-
     logger.info(f"left is {left}, right is {right}, op is {op}")
 
-    if isinstance(op, ast.Add):
+    # Map AST operation nodes to LLVM IR builder methods
-        builder.store(builder.add(left, right), local_sym_tab[var_name].var)
+    op_map = {
-    elif isinstance(op, ast.Sub):
+        ast.Add: builder.add,
-        builder.store(builder.sub(left, right), local_sym_tab[var_name].var)
+        ast.Sub: builder.sub,
-    elif isinstance(op, ast.Mult):
+        ast.Mult: builder.mul,
-        builder.store(builder.mul(left, right), local_sym_tab[var_name].var)
+        ast.Div: builder.sdiv,
-    elif isinstance(op, ast.Div):
+        ast.Mod: builder.srem,
-        builder.store(builder.sdiv(left, right), local_sym_tab[var_name].var)
+        ast.LShift: builder.shl,
-    elif isinstance(op, ast.Mod):
+        ast.RShift: builder.lshr,
-        builder.store(builder.srem(left, right), local_sym_tab[var_name].var)
+        ast.BitOr: builder.or_,
-    elif isinstance(op, ast.LShift):
+        ast.BitXor: builder.xor,
-        builder.store(builder.shl(left, right), local_sym_tab[var_name].var)
+        ast.BitAnd: builder.and_,
-    elif isinstance(op, ast.RShift):
+        ast.FloorDiv: builder.udiv,
-        builder.store(builder.lshr(left, right), local_sym_tab[var_name].var)
+    }
-    elif isinstance(op, ast.BitOr):
+
-        builder.store(builder.or_(left, right), local_sym_tab[var_name].var)
+    if type(op) in op_map:
-    elif isinstance(op, ast.BitXor):
+        result = op_map[type(op)](left, right)
-        builder.store(builder.xor(left, right), local_sym_tab[var_name].var)
+        return result
-    elif isinstance(op, ast.BitAnd):
-        builder.store(builder.and_(left, right), local_sym_tab[var_name].var)
-    elif isinstance(op, ast.FloorDiv):
-        builder.store(builder.udiv(left, right), local_sym_tab[var_name].var)
     else:
         raise SyntaxError("Unsupported binary operation")
+
+
+def handle_binary_op(rval, builder, var_name, local_sym_tab):
+    result = handle_binary_op_impl(rval, builder, local_sym_tab)
+    if var_name and var_name in local_sym_tab:
+        logger.info(
+            f"Storing result {result} into variable {local_sym_tab[var_name].var}"
+        )
+        builder.store(result, local_sym_tab[var_name].var)
+    return result, result.type

pythonbpf/codegen.py

@@ -1,11 +1,11 @@
 import ast
 from llvmlite import ir
 from .license_pass import license_processing
-from .functions_pass import func_proc
+from .functions import func_proc
 from .maps import maps_proc
 from .structs import structs_proc
 from .globals_pass import globals_processing
-from .debuginfo import DW_LANG_C11, DwarfBehaviorEnum
+from .debuginfo import DW_LANG_C11, DwarfBehaviorEnum, DebugInfoGenerator
 import os
 import subprocess
 import inspect
@@ -48,7 +48,7 @@ def processor(source_code, filename, module):
     globals_processing(tree, module)
 
 
-def compile_to_ir(filename: str, output: str, loglevel=logging.WARNING):
+def compile_to_ir(filename: str, output: str, loglevel=logging.INFO):
     logging.basicConfig(
         level=loglevel, format="%(asctime)s [%(levelname)s] %(name)s: %(message)s"
     )
@@ -60,33 +60,17 @@ def compile_to_ir(filename: str, output: str, loglevel=logging.WARNING):
     module.triple = "bpf"
 
     if not hasattr(module, "_debug_compile_unit"):
-        module._file_metadata = module.add_debug_info(
+        debug_generator = DebugInfoGenerator(module)
-            "DIFile",
+        debug_generator.generate_file_metadata(filename, os.path.dirname(filename))
-            {  # type: ignore
+        debug_generator.generate_debug_cu(
-                "filename": filename,
+            DW_LANG_C11,
-                "directory": os.path.dirname(filename),
+            f"PythonBPF {VERSION}",
-            },
+            True,  # TODO: This is probably not true
-        )
-
-        module._debug_compile_unit = module.add_debug_info(
-            "DICompileUnit",
-            {  # type: ignore
-                "language": DW_LANG_C11,
-                "file": module._file_metadata,  # type: ignore
-                "producer": f"PythonBPF {VERSION}",
-                "isOptimized": True,  # TODO: This is probably not true
             # TODO: add a global field here that keeps track of all the globals. Works without it, but I think it might
             # be required for kprobes.
-                "runtimeVersion": 0,
+            True,
-                "emissionKind": 1,
-                "splitDebugInlining": False,
-                "nameTableKind": 0,
-            },
-            is_distinct=True,
         )
 
-        module.add_named_metadata("llvm.dbg.cu", module._debug_compile_unit)  # type: ignore
-
     processor(source, filename, module)
 
     wchar_size = module.add_metadata(
@@ -137,7 +121,7 @@ def compile_to_ir(filename: str, output: str, loglevel=logging.WARNING):
     return output
 
 
-def compile(loglevel=logging.WARNING) -> bool:
+def compile(loglevel=logging.INFO) -> bool:
     # Look one level up the stack to the caller of this function
     caller_frame = inspect.stack()[1]
     caller_file = Path(caller_frame.filename).resolve()
@@ -170,7 +154,7 @@ def compile(loglevel=logging.WARNING) -> bool:
     return success
 
 
-def BPF(loglevel=logging.WARNING) -> BpfProgram:
+def BPF(loglevel=logging.INFO) -> BpfProgram:
     caller_frame = inspect.stack()[1]
     src = inspect.getsource(caller_frame.frame)
     with tempfile.NamedTemporaryFile(

pythonbpf/debuginfo/debug_info_generator.py

@@ -12,6 +12,34 @@ class DebugInfoGenerator:
         self.module = module
         self._type_cache = {}  # Cache for common debug types
 
+    def generate_file_metadata(self, filename, dirname):
+        self.module._file_metadata = self.module.add_debug_info(
+            "DIFile",
+            {  # type: ignore
+                "filename": filename,
+                "directory": dirname,
+            },
+        )
+
+    def generate_debug_cu(
+        self, language, producer: str, is_optimized: bool, is_distinct: bool
+    ):
+        self.module._debug_compile_unit = self.module.add_debug_info(
+            "DICompileUnit",
+            {  # type: ignore
+                "language": language,
+                "file": self.module._file_metadata,  # type: ignore
+                "producer": producer,
+                "isOptimized": is_optimized,
+                "runtimeVersion": 0,
+                "emissionKind": 1,
+                "splitDebugInlining": False,
+                "nameTableKind": 0,
+            },
+            is_distinct=is_distinct,
+        )
+        self.module.add_named_metadata("llvm.dbg.cu", self.module._debug_compile_unit)  # type: ignore
+
     def get_basic_type(self, name: str, size: int, encoding: int) -> Any:
         """Get or create a basic type with caching"""
         key = (name, size, encoding)

pythonbpf/expr_pass.py

@@ -2,10 +2,136 @@ import ast
 from llvmlite import ir
 from logging import Logger
 import logging
+from typing import Dict
+
+from .type_deducer import ctypes_to_ir, is_ctypes
 
 logger: Logger = logging.getLogger(__name__)
 
 
+def _handle_name_expr(expr: ast.Name, local_sym_tab: Dict, builder: ir.IRBuilder):
+    """Handle ast.Name expressions."""
+    if expr.id in local_sym_tab:
+        var = local_sym_tab[expr.id].var
+        val = builder.load(var)
+        return val, local_sym_tab[expr.id].ir_type
+    else:
+        logger.info(f"Undefined variable {expr.id}")
+        return None
+
+
+def _handle_constant_expr(expr: ast.Constant):
+    """Handle ast.Constant expressions."""
+    if isinstance(expr.value, int):
+        return ir.Constant(ir.IntType(64), expr.value), ir.IntType(64)
+    elif isinstance(expr.value, bool):
+        return ir.Constant(ir.IntType(1), int(expr.value)), ir.IntType(1)
+    else:
+        logger.info("Unsupported constant type")
+        return None
+
+
+def _handle_attribute_expr(
+    expr: ast.Attribute,
+    local_sym_tab: Dict,
+    structs_sym_tab: Dict,
+    builder: ir.IRBuilder,
+):
+    """Handle ast.Attribute expressions for struct field access."""
+    if isinstance(expr.value, ast.Name):
+        var_name = expr.value.id
+        attr_name = expr.attr
+        if var_name in local_sym_tab:
+            var_ptr, var_type, var_metadata = local_sym_tab[var_name]
+            logger.info(f"Loading attribute {attr_name} from variable {var_name}")
+            logger.info(f"Variable type: {var_type}, Variable ptr: {var_ptr}")
+
+            metadata = structs_sym_tab[var_metadata]
+            if attr_name in metadata.fields:
+                gep = metadata.gep(builder, var_ptr, attr_name)
+                val = builder.load(gep)
+                field_type = metadata.field_type(attr_name)
+                return val, field_type
+    return None
+
+
+def _handle_deref_call(expr: ast.Call, local_sym_tab: Dict, builder: ir.IRBuilder):
+    """Handle deref function calls."""
+    logger.info(f"Handling deref {ast.dump(expr)}")
+    if len(expr.args) != 1:
+        logger.info("deref takes exactly one argument")
+        return None
+
+    arg = expr.args[0]
+    if (
+        isinstance(arg, ast.Call)
+        and isinstance(arg.func, ast.Name)
+        and arg.func.id == "deref"
+    ):
+        logger.info("Multiple deref not supported")
+        return None
+
+    if isinstance(arg, ast.Name):
+        if arg.id in local_sym_tab:
+            arg_ptr = local_sym_tab[arg.id].var
+        else:
+            logger.info(f"Undefined variable {arg.id}")
+            return None
+    else:
+        logger.info("Unsupported argument type for deref")
+        return None
+
+    if arg_ptr is None:
+        logger.info("Failed to evaluate deref argument")
+        return None
+
+    # Load the value from pointer
+    val = builder.load(arg_ptr)
+    return val, local_sym_tab[arg.id].ir_type
+
+
+def _handle_ctypes_call(
+    func,
+    module,
+    builder,
+    expr,
+    local_sym_tab,
+    map_sym_tab,
+    structs_sym_tab=None,
+):
+    """Handle ctypes type constructor calls."""
+    if len(expr.args) != 1:
+        logger.info("ctypes constructor takes exactly one argument")
+        return None
+
+    arg = expr.args[0]
+    val = eval_expr(
+        func,
+        module,
+        builder,
+        arg,
+        local_sym_tab,
+        map_sym_tab,
+        structs_sym_tab,
+    )
+    if val is None:
+        logger.info("Failed to evaluate argument to ctypes constructor")
+        return None
+    call_type = expr.func.id
+    expected_type = ctypes_to_ir(call_type)
+
+    if val[1] != expected_type:
+        # NOTE: We are only considering casting to and from int types for now
+        if isinstance(val[1], ir.IntType) and isinstance(expected_type, ir.IntType):
+            if val[1].width < expected_type.width:
+                val = (builder.sext(val[0], expected_type), expected_type)
+            else:
+                val = (builder.trunc(val[0], expected_type), expected_type)
+        else:
+            raise ValueError(f"Type mismatch: expected {expected_type}, got {val[1]}")
+    return val
+
+
 def eval_expr(
     func,
     module,
@@ -17,55 +143,30 @@ def eval_expr(
 ):
     logger.info(f"Evaluating expression: {ast.dump(expr)}")
     if isinstance(expr, ast.Name):
-        if expr.id in local_sym_tab:
+        return _handle_name_expr(expr, local_sym_tab, builder)
-            var = local_sym_tab[expr.id].var
-            val = builder.load(var)
-            return val, local_sym_tab[expr.id].ir_type  # return value and type
-        else:
-            logger.info(f"Undefined variable {expr.id}")
-            return None
     elif isinstance(expr, ast.Constant):
-        if isinstance(expr.value, int):
+        return _handle_constant_expr(expr)
-            return ir.Constant(ir.IntType(64), expr.value), ir.IntType(64)
-        elif isinstance(expr.value, bool):
-            return ir.Constant(ir.IntType(1), int(expr.value)), ir.IntType(1)
-        else:
-            logger.info("Unsupported constant type")
-            return None
     elif isinstance(expr, ast.Call):
+        if isinstance(expr.func, ast.Name) and expr.func.id == "deref":
+            return _handle_deref_call(expr, local_sym_tab, builder)
+
+        if isinstance(expr.func, ast.Name) and is_ctypes(expr.func.id):
+            return _handle_ctypes_call(
+                func,
+                module,
+                builder,
+                expr,
+                local_sym_tab,
+                map_sym_tab,
+                structs_sym_tab,
+            )
+
         # delayed import to avoid circular dependency
         from pythonbpf.helper import HelperHandlerRegistry, handle_helper_call
 
-        if isinstance(expr.func, ast.Name):
+        if isinstance(expr.func, ast.Name) and HelperHandlerRegistry.has_handler(
-            # check deref
+            expr.func.id
-            if expr.func.id == "deref":
-                logger.info(f"Handling deref {ast.dump(expr)}")
-                if len(expr.args) != 1:
-                    logger.info("deref takes exactly one argument")
-                    return None
-                arg = expr.args[0]
-                if (
-                    isinstance(arg, ast.Call)
-                    and isinstance(arg.func, ast.Name)
-                    and arg.func.id == "deref"
         ):
-                    logger.info("Multiple deref not supported")
-                    return None
-                if isinstance(arg, ast.Name):
-                    if arg.id in local_sym_tab:
-                        arg = local_sym_tab[arg.id].var
-                    else:
-                        logger.info(f"Undefined variable {arg.id}")
-                        return None
-                if arg is None:
-                    logger.info("Failed to evaluate deref argument")
-                    return None
-                # Since we are handling only name case, directly take type from sym tab
-                val = builder.load(arg)
-                return val, local_sym_tab[expr.args[0].id].ir_type
-
-            # check for helpers
-            if HelperHandlerRegistry.has_handler(expr.func.id):
             return handle_helper_call(
                 expr,
                 module,
@@ -106,19 +207,11 @@ def eval_expr(
                             structs_sym_tab,
                         )
     elif isinstance(expr, ast.Attribute):
-        if isinstance(expr.value, ast.Name):
+        return _handle_attribute_expr(expr, local_sym_tab, structs_sym_tab, builder)
-            var_name = expr.value.id
+    elif isinstance(expr, ast.BinOp):
-            attr_name = expr.attr
+        from pythonbpf.binary_ops import handle_binary_op
-            if var_name in local_sym_tab:
+
-                var_ptr, var_type, var_metadata = local_sym_tab[var_name]
+        return handle_binary_op(expr, builder, None, local_sym_tab)
-                logger.info(f"Loading attribute {attr_name} from variable {var_name}")
-                logger.info(f"Variable type: {var_type}, Variable ptr: {var_ptr}")
-                metadata = structs_sym_tab[var_metadata]
-                if attr_name in metadata.fields:
-                    gep = metadata.gep(builder, var_ptr, attr_name)
-                    val = builder.load(gep)
-                    field_type = metadata.field_type(attr_name)
-                    return val, field_type
     logger.info("Unsupported expression evaluation")
     return None
 

pythonbpf/functions/__init__.py

@@ -0,0 +1,3 @@
+from .functions_pass import func_proc
+
+__all__ = ["func_proc"]

pythonbpf/functions/func_registry_handlers.py

@@ -0,0 +1,22 @@
+from typing import Dict
+
+
+class StatementHandlerRegistry:
+    """Registry for statement handlers."""
+
+    _handlers: Dict = {}
+
+    @classmethod
+    def register(cls, stmt_type):
+        """Register a handler for a specific statement type."""
+
+        def decorator(handler):
+            cls._handlers[stmt_type] = handler
+            return handler
+
+        return decorator
+
+    @classmethod
+    def __getitem__(cls, stmt_type):
+        """Get the handler for a specific statement type."""
+        return cls._handlers.get(stmt_type, None)

pythonbpf/functions/functions_pass.py

@@ -4,10 +4,13 @@ import logging
 from typing import Any
 from dataclasses import dataclass
 
-from .helper import HelperHandlerRegistry, handle_helper_call
+from pythonbpf.helper import HelperHandlerRegistry, handle_helper_call
-from .type_deducer import ctypes_to_ir
+from pythonbpf.type_deducer import ctypes_to_ir
-from .binary_ops import handle_binary_op
+from pythonbpf.binary_ops import handle_binary_op
-from .expr_pass import eval_expr, handle_expr
+from pythonbpf.expr_pass import eval_expr, handle_expr
+
+from .return_utils import _handle_none_return, _handle_xdp_return, _is_xdp_name
+
 
 logger = logging.getLogger(__name__)
 
@@ -146,8 +149,7 @@ def handle_assign(
                     local_sym_tab[var_name].var,
                 )
                 logger.info(
-                    f"Assigned {call_type} constant "
+                    f"Assigned {call_type} constant {rval.args[0].value} to {var_name}"
-                    f"{rval.args[0].value} to {var_name}"
                 )
             elif HelperHandlerRegistry.has_handler(call_type):
                 # var = builder.alloca(ir.IntType(64), name=var_name)
@@ -192,6 +194,21 @@ def handle_assign(
         elif isinstance(rval.func, ast.Attribute):
             logger.info(f"Assignment call attribute: {ast.dump(rval.func)}")
             if isinstance(rval.func.value, ast.Name):
+                if rval.func.value.id in map_sym_tab:
+                    map_name = rval.func.value.id
+                    method_name = rval.func.attr
+                    if HelperHandlerRegistry.has_handler(method_name):
+                        val = handle_helper_call(
+                            rval,
+                            module,
+                            builder,
+                            func,
+                            local_sym_tab,
+                            map_sym_tab,
+                            structs_sym_tab,
+                        )
+                        builder.store(val[0], local_sym_tab[var_name].var)
+                else:
                     # TODO: probably a struct access
                     logger.info(f"TODO STRUCT ACCESS {ast.dump(rval)}")
             elif isinstance(rval.func.value, ast.Call) and isinstance(
@@ -218,9 +235,7 @@ def handle_assign(
         else:
             logger.info("Unsupported assignment call function type")
     elif isinstance(rval, ast.BinOp):
-        handle_binary_op(
+        handle_binary_op(rval, builder, var_name, local_sym_tab)
-            rval, module, builder, var_name, local_sym_tab, map_sym_tab, func
-        )
     else:
         logger.info("Unsupported assignment value type")
 
@@ -338,6 +353,27 @@ def handle_if(
     builder.position_at_end(merge_block)
 
 
+def handle_return(builder, stmt, local_sym_tab, ret_type):
+    logger.info(f"Handling return statement: {ast.dump(stmt)}")
+    if stmt.value is None:
+        return _handle_none_return(builder)
+    elif isinstance(stmt.value, ast.Name) and _is_xdp_name(stmt.value.id):
+        return _handle_xdp_return(stmt, builder, ret_type)
+    else:
+        val = eval_expr(
+            func=None,
+            module=None,
+            builder=builder,
+            expr=stmt.value,
+            local_sym_tab=local_sym_tab,
+            map_sym_tab={},
+            structs_sym_tab={},
+        )
+        logger.info(f"Evaluated return expression to {val}")
+        builder.ret(val[0])
+        return True
+
+
 def process_stmt(
     func,
     module,
@@ -371,36 +407,12 @@ def process_stmt(
             func, module, builder, stmt, map_sym_tab, local_sym_tab, structs_sym_tab
         )
     elif isinstance(stmt, ast.Return):
-        if stmt.value is None:
+        did_return = handle_return(
-            builder.ret(ir.Constant(ir.IntType(32), 0))
+            builder,
-            did_return = True
+            stmt,
-        elif (
+            local_sym_tab,
-            isinstance(stmt.value, ast.Call)
+            ret_type,
-            and isinstance(stmt.value.func, ast.Name)
-            and len(stmt.value.args) == 1
-            and isinstance(stmt.value.args[0], ast.Constant)
-            and isinstance(stmt.value.args[0].value, int)
-        ):
-            call_type = stmt.value.func.id
-            if ctypes_to_ir(call_type) != ret_type:
-                raise ValueError(
-                    "Return type mismatch: expected"
-                    f"{ctypes_to_ir(call_type)}, got {call_type}"
         )
-            else:
-                builder.ret(ir.Constant(ret_type, stmt.value.args[0].value))
-                did_return = True
-        elif isinstance(stmt.value, ast.Name):
-            if stmt.value.id == "XDP_PASS":
-                builder.ret(ir.Constant(ret_type, 2))
-                did_return = True
-            elif stmt.value.id == "XDP_DROP":
-                builder.ret(ir.Constant(ret_type, 1))
-                did_return = True
-            else:
-                raise ValueError("Failed to evaluate return expression")
-        else:
-            raise ValueError("Unsupported return value")
     return did_return
 
 
@@ -442,6 +454,9 @@ def allocate_mem(
                 continue
             var_name = target.id
             rval = stmt.value
+            if var_name in local_sym_tab:
+                logger.info(f"Variable {var_name} already allocated")
+                continue
             if isinstance(rval, ast.Call):
                 if isinstance(rval.func, ast.Name):
                     call_type = rval.func.id
@@ -470,8 +485,7 @@ def allocate_mem(
                         var = builder.alloca(ir_type, name=var_name)
                         has_metadata = True
                         logger.info(
-                            f"Pre-allocated variable {var_name} "
+                            f"Pre-allocated variable {var_name} for struct {call_type}"
-                            f"for struct {call_type}"
                         )
                 elif isinstance(rval.func, ast.Attribute):
                     ir_type = ir.PointerType(ir.IntType(64))
@@ -555,7 +569,7 @@ def process_func_body(
         )
 
     if not did_return:
-        builder.ret(ir.Constant(ir.IntType(32), 0))
+        builder.ret(ir.Constant(ir.IntType(64), 0))
 
 
 def process_bpf_chunk(func_node, module, return_type, map_sym_tab, structs_sym_tab):

pythonbpf/functions/return_utils.py

@@ -0,0 +1,45 @@
+import logging
+import ast
+
+from llvmlite import ir
+
+logger: logging.Logger = logging.getLogger(__name__)
+
+XDP_ACTIONS = {
+    "XDP_ABORTED": 0,
+    "XDP_DROP": 1,
+    "XDP_PASS": 2,
+    "XDP_TX": 3,
+    "XDP_REDIRECT": 4,
+}
+
+
+def _handle_none_return(builder) -> bool:
+    """Handle return or return None -> returns 0."""
+    builder.ret(ir.Constant(ir.IntType(64), 0))
+    logger.debug("Generated default return: 0")
+    return True
+
+
+def _is_xdp_name(name: str) -> bool:
+    """Check if a name is an XDP action"""
+    return name in XDP_ACTIONS
+
+
+def _handle_xdp_return(stmt: ast.Return, builder, ret_type) -> bool:
+    """Handle XDP returns"""
+    if not isinstance(stmt.value, ast.Name):
+        return False
+
+    action_name = stmt.value.id
+
+    if action_name not in XDP_ACTIONS:
+        raise ValueError(
+            f"Unknown XDP action: {action_name}. Available: {XDP_ACTIONS.keys()}"
+        )
+        return False
+
+    value = XDP_ACTIONS[action_name]
+    builder.ret(ir.Constant(ret_type, value))
+    logger.debug(f"Generated XDP action return: {action_name} = {value}")
+    return True

pythonbpf/helper/bpf_helper_handler.py

@@ -62,7 +62,7 @@ def bpf_map_lookup_elem_emitter(
     """
     if not call.args or len(call.args) != 1:
         raise ValueError(
-            "Map lookup expects exactly one argument (key), got " f"{len(call.args)}"
+            f"Map lookup expects exactly one argument (key), got {len(call.args)}"
         )
     key_ptr = get_or_create_ptr_from_arg(call.args[0], builder, local_sym_tab)
     map_void_ptr = builder.bitcast(map_ptr, ir.PointerType())
@@ -145,8 +145,7 @@ def bpf_map_update_elem_emitter(
     """
     if not call.args or len(call.args) < 2 or len(call.args) > 3:
         raise ValueError(
-            "Map update expects 2 or 3 args (key, value, flags), "
+            f"Map update expects 2 or 3 args (key, value, flags), got {len(call.args)}"
-            f"got {len(call.args)}"
         )
 
     key_arg = call.args[0]
@@ -196,7 +195,7 @@ def bpf_map_delete_elem_emitter(
     """
     if not call.args or len(call.args) != 1:
         raise ValueError(
-            "Map delete expects exactly one argument (key), got " f"{len(call.args)}"
+            f"Map delete expects exactly one argument (key), got {len(call.args)}"
         )
     key_ptr = get_or_create_ptr_from_arg(call.args[0], builder, local_sym_tab)
     map_void_ptr = builder.bitcast(map_ptr, ir.PointerType())
@@ -255,7 +254,7 @@ def bpf_perf_event_output_handler(
 ):
     if len(call.args) != 1:
         raise ValueError(
-            "Perf event output expects exactly one argument, " f"got {len(call.args)}"
+            f"Perf event output expects exactly one argument, got {len(call.args)}"
         )
     data_arg = call.args[0]
     ctx_ptr = func.args[0]  # First argument to the function is ctx

pythonbpf/helper/helper_utils.py

@@ -270,7 +270,7 @@ def _prepare_expr_args(expr, func, module, builder, local_sym_tab, struct_sym_ta
                 val = builder.sext(val, ir.IntType(64))
         else:
             logger.warning(
-                "Only int and ptr supported in bpf_printk args. " "Others default to 0."
+                "Only int and ptr supported in bpf_printk args. Others default to 0."
             )
             val = ir.Constant(ir.IntType(64), 0)
         return val

pythonbpf/maps/maps_pass.py

@@ -278,9 +278,7 @@ def process_bpf_map(func_node, module):
         if handler:
             return handler(map_name, rval, module)
         else:
-            logger.warning(
+            logger.warning(f"Unknown map type {rval.func.id}, defaulting to HashMap")
-                f"Unknown map type " f"{rval.func.id}, defaulting to HashMap"
-            )
             return process_hash_map(map_name, rval, module)
     else:
         raise ValueError("Function under @map must return a map")

pythonbpf/type_deducer.py

@@ -1,10 +1,7 @@
 from llvmlite import ir
 
 # TODO: THIS IS NOT SUPPOSED TO MATCH STRINGS :skull:
-
+mapping = {
-
-def ctypes_to_ir(ctype: str):
-    mapping = {
     "c_int8": ir.IntType(8),
     "c_uint8": ir.IntType(8),
     "c_int16": ir.IntType(16),
@@ -18,7 +15,14 @@ def ctypes_to_ir(ctype: str):
     "c_void_p": ir.IntType(64),
     # Not so sure about this one
     "str": ir.PointerType(ir.IntType(8)),
-    }
+}
+
+
+def ctypes_to_ir(ctype: str):
     if ctype in mapping:
         return mapping[ctype]
     raise NotImplementedError(f"No mapping for {ctype}")
+
+
+def is_ctypes(ctype: str) -> bool:
+    return ctype in mapping

tests/failing_tests/direct_assign.py

@@ -4,6 +4,18 @@ from pythonbpf.maps import HashMap
 
 from ctypes import c_void_p, c_int64
 
+# NOTE: I have decided to not fix this example for now.
+# The issue is in line 31, where we are passing an expression.
+# The update helper expects a pointer type. But the problem is
+# that we must allocate the space for said pointer in the first
+# basic block. As that usage is in a different basic block, we
+# are unable to cast the expression to a pointer type. (as we never
+# allocated space for it).
+# Shall we change our space allocation logic? That allows users to
+# spam the same helper with the same args, and still run out of
+# stack space. So we consider this usage invalid for now.
+# Might fix it later.
+
 
 @bpf
 @map
@@ -14,12 +26,12 @@ def count() -> HashMap:
 @bpf
 @section("xdp")
 def hello_world(ctx: c_void_p) -> c_int64:
-    prev = count().lookup(0)
+    prev = count.lookup(0)
     if prev:
-        count().update(0, prev + 1)
+        count.update(0, prev + 1)
         return XDP_PASS
     else:
-        count().update(0, 1)
+        count.update(0, 1)
 
     return XDP_PASS
 

tests/failing_tests/named_arg.py

@@ -0,0 +1,40 @@
+from pythonbpf import bpf, map, section, bpfglobal, compile
+from pythonbpf.helper import XDP_PASS
+from pythonbpf.maps import HashMap
+
+from ctypes import c_void_p, c_int64
+
+# NOTE: This example exposes the problems with our typing system.
+# We can't do steps on line 25 and 27.
+# prev is of type i64**. For prev + 1, we deref it down to i64
+# To assign it back to prev, we need to go back to i64**.
+# We cannot allocate space for the intermediate type now.
+# We probably need to track the ref/deref chain for each variable.
+
+@bpf
+@map
+def count() -> HashMap:
+    return HashMap(key=c_int64, value=c_int64, max_entries=1)
+
+
+@bpf
+@section("xdp")
+def hello_world(ctx: c_void_p) -> c_int64:
+    prev = count.lookup(0)
+    if prev:
+        prev = prev + 1
+        count.update(0, prev)
+        return XDP_PASS
+    else:
+        count.update(0, 1)
+
+    return XDP_PASS
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/binops.py

@@ -3,9 +3,9 @@ from ctypes import c_void_p, c_int64
 
 
 @bpf
-@section("sometag1")
+@section("tracepoint/syscalls/sys_enter_sync")
 def sometag(ctx: c_void_p) -> c_int64:
-    a = 1 + 2 + 1
+    a = 1 + 2 + 1 + 12 + 13
     print(f"{a}")
     return c_int64(0)
 

tests/passing_tests/binops1.py

@@ -0,0 +1,20 @@
+from pythonbpf import compile, bpf, section, bpfglobal
+from ctypes import c_void_p, c_int64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_sync")
+def sometag(ctx: c_void_p) -> c_int64:
+    b = 1 + 2
+    a = 1 + b
+    print(f"{a}")
+    return c_int64(0)
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/binop_const.py

@@ -0,0 +1,18 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    print("Hello, World!")
+    return 1 + 1 - 2
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/binop_var.py

@@ -0,0 +1,19 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    print("Hello, World!")
+    a = 2
+    return a - 2
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/int.py

@@ -0,0 +1,18 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    print("Hello, World!")
+    return 1
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/null.py

@@ -0,0 +1,18 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    print("Hello, World!")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/typecast_binops.py

@@ -0,0 +1,20 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int32
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int32:
+    print("Hello, World!")
+    a = 1  # int64
+    x = 1  # int64
+    return c_int32(a - x)  # typecast to int32
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/typecast_const.py

@@ -0,0 +1,18 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int32
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int32:
+    print("Hello, World!")
+    return c_int32(1)
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/typecast_var.py

@@ -0,0 +1,19 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int32
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int32:
+    print("Hello, World!")
+    a = 1 # int64
+    return c_int32(a) # typecast to int32
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/var.py

@@ -0,0 +1,19 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    print("Hello, World!")
+    a = 1
+    return a
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/return/xdp.py

@@ -0,0 +1,19 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64
+from pythonbpf.helper import XDP_PASS
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    print("Hello, World!")
+    return XDP_PASS
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/var_rval.py

@@ -1,3 +1,5 @@
+import logging
+
 from pythonbpf import compile, bpf, section, bpfglobal
 from ctypes import c_void_p, c_int64
 
@@ -5,8 +7,7 @@ from ctypes import c_void_p, c_int64
 @bpf
 @section("sometag1")
 def sometag(ctx: c_void_p) -> c_int64:
-    b = 1 + 2
+    a = 1 - 1
-    a = 1 + b
     return c_int64(a)
 
 
@@ -16,4 +17,4 @@ def LICENSE() -> str:
     return "GPL"
 
 
-compile()
+compile(loglevel=logging.INFO)