Merge pull request #40 from pythonbpf/refactor_assign

Refactor assignment statement handling and the typing mechanism around it

pythonbpf/allocation_pass.py

@@ -0,0 +1,191 @@
+import ast
+import logging
+
+from llvmlite import ir
+from dataclasses import dataclass
+from typing import Any
+from pythonbpf.helper import HelperHandlerRegistry
+from pythonbpf.type_deducer import ctypes_to_ir
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class LocalSymbol:
+    var: ir.AllocaInstr
+    ir_type: ir.Type
+    metadata: Any = None
+
+    def __iter__(self):
+        yield self.var
+        yield self.ir_type
+        yield self.metadata
+
+
+def _is_helper_call(call_node):
+    """Check if a call node is a BPF helper function call."""
+    if isinstance(call_node.func, ast.Name):
+        # Exclude print from requiring temps (handles f-strings differently)
+        func_name = call_node.func.id
+        return HelperHandlerRegistry.has_handler(func_name) and func_name != "print"
+
+    elif isinstance(call_node.func, ast.Attribute):
+        return HelperHandlerRegistry.has_handler(call_node.func.attr)
+
+    return False
+
+
+def handle_assign_allocation(builder, stmt, local_sym_tab, structs_sym_tab):
+    """Handle memory allocation for assignment statements."""
+
+    # Validate assignment
+    if len(stmt.targets) != 1:
+        logger.warning("Multi-target assignment not supported, skipping allocation")
+        return
+
+    target = stmt.targets[0]
+
+    # Skip non-name targets (e.g., struct field assignments)
+    if isinstance(target, ast.Attribute):
+        logger.debug(f"Struct field assignment to {target.attr}, no allocation needed")
+        return
+
+    if not isinstance(target, ast.Name):
+        logger.warning(f"Unsupported assignment target type: {type(target).__name__}")
+        return
+
+    var_name = target.id
+    rval = stmt.value
+
+    # Skip if already allocated
+    if var_name in local_sym_tab:
+        logger.debug(f"Variable {var_name} already allocated, skipping")
+        return
+
+    # Determine type and allocate based on rval
+    if isinstance(rval, ast.Call):
+        _allocate_for_call(builder, var_name, rval, local_sym_tab, structs_sym_tab)
+    elif isinstance(rval, ast.Constant):
+        _allocate_for_constant(builder, var_name, rval, local_sym_tab)
+    elif isinstance(rval, ast.BinOp):
+        _allocate_for_binop(builder, var_name, local_sym_tab)
+    else:
+        logger.warning(
+            f"Unsupported assignment value type for {var_name}: {type(rval).__name__}"
+        )
+
+
+def _allocate_for_call(builder, var_name, rval, local_sym_tab, structs_sym_tab):
+    """Allocate memory for variable assigned from a call."""
+
+    if isinstance(rval.func, ast.Name):
+        call_type = rval.func.id
+
+        # C type constructors
+        if call_type in ("c_int32", "c_int64", "c_uint32", "c_uint64"):
+            ir_type = ctypes_to_ir(call_type)
+            var = builder.alloca(ir_type, name=var_name)
+            var.align = ir_type.width // 8
+            local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+            logger.info(f"Pre-allocated {var_name} as {call_type}")
+
+        # Helper functions
+        elif HelperHandlerRegistry.has_handler(call_type):
+            ir_type = ir.IntType(64)  # Assume i64 return type
+            var = builder.alloca(ir_type, name=var_name)
+            var.align = 8
+            local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+            logger.info(f"Pre-allocated {var_name} for helper {call_type}")
+
+        # Deref function
+        elif call_type == "deref":
+            ir_type = ir.IntType(64)  # Assume i64 return type
+            var = builder.alloca(ir_type, name=var_name)
+            var.align = 8
+            local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+            logger.info(f"Pre-allocated {var_name} for deref")
+
+        # Struct constructors
+        elif call_type in structs_sym_tab:
+            struct_info = structs_sym_tab[call_type]
+            var = builder.alloca(struct_info.ir_type, name=var_name)
+            local_sym_tab[var_name] = LocalSymbol(var, struct_info.ir_type, call_type)
+            logger.info(f"Pre-allocated {var_name} for struct {call_type}")
+
+        else:
+            logger.warning(f"Unknown call type for allocation: {call_type}")
+
+    elif isinstance(rval.func, ast.Attribute):
+        # Map method calls - need double allocation for ptr handling
+        _allocate_for_map_method(builder, var_name, local_sym_tab)
+
+    else:
+        logger.warning(f"Unsupported call function type for {var_name}")
+
+
+def _allocate_for_map_method(builder, var_name, local_sym_tab):
+    """Allocate memory for variable assigned from map method (double alloc)."""
+
+    # Main variable (pointer to pointer)
+    ir_type = ir.PointerType(ir.IntType(64))
+    var = builder.alloca(ir_type, name=var_name)
+    local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+
+    # Temporary variable for computed values
+    tmp_ir_type = ir.IntType(64)
+    var_tmp = builder.alloca(tmp_ir_type, name=f"{var_name}_tmp")
+    local_sym_tab[f"{var_name}_tmp"] = LocalSymbol(var_tmp, tmp_ir_type)
+
+    logger.info(f"Pre-allocated {var_name} and {var_name}_tmp for map method")
+
+
+def _allocate_for_constant(builder, var_name, rval, local_sym_tab):
+    """Allocate memory for variable assigned from a constant."""
+
+    if isinstance(rval.value, bool):
+        ir_type = ir.IntType(1)
+        var = builder.alloca(ir_type, name=var_name)
+        var.align = 1
+        local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+        logger.info(f"Pre-allocated {var_name} as bool")
+
+    elif isinstance(rval.value, int):
+        ir_type = ir.IntType(64)
+        var = builder.alloca(ir_type, name=var_name)
+        var.align = 8
+        local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+        logger.info(f"Pre-allocated {var_name} as i64")
+
+    elif isinstance(rval.value, str):
+        ir_type = ir.PointerType(ir.IntType(8))
+        var = builder.alloca(ir_type, name=var_name)
+        var.align = 8
+        local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+        logger.info(f"Pre-allocated {var_name} as string")
+
+    else:
+        logger.warning(
+            f"Unsupported constant type for {var_name}: {type(rval.value).__name__}"
+        )
+
+
+def _allocate_for_binop(builder, var_name, local_sym_tab):
+    """Allocate memory for variable assigned from a binary operation."""
+    ir_type = ir.IntType(64)  # Assume i64 result
+    var = builder.alloca(ir_type, name=var_name)
+    var.align = 8
+    local_sym_tab[var_name] = LocalSymbol(var, ir_type)
+    logger.info(f"Pre-allocated {var_name} for binop result")
+
+
+def allocate_temp_pool(builder, max_temps, local_sym_tab):
+    """Allocate the temporary scratch space pool for helper arguments."""
+    if max_temps == 0:
+        return
+
+    logger.info(f"Allocating temp pool of {max_temps} variables")
+    for i in range(max_temps):
+        temp_name = f"__helper_temp_{i}"
+        temp_var = builder.alloca(ir.IntType(64), name=temp_name)
+        temp_var.align = 8
+        local_sym_tab[temp_name] = LocalSymbol(temp_var, ir.IntType(64))

pythonbpf/assign_pass.py

@@ -0,0 +1,108 @@
+import ast
+import logging
+from llvmlite import ir
+from pythonbpf.expr import eval_expr
+
+logger = logging.getLogger(__name__)
+
+
+def handle_struct_field_assignment(
+    func, module, builder, target, rval, local_sym_tab, map_sym_tab, structs_sym_tab
+):
+    """Handle struct field assignment (obj.field = value)."""
+
+    var_name = target.value.id
+    field_name = target.attr
+
+    if var_name not in local_sym_tab:
+        logger.error(f"Variable '{var_name}' not found in symbol table")
+        return
+
+    struct_type = local_sym_tab[var_name].metadata
+    struct_info = structs_sym_tab[struct_type]
+
+    if field_name not in struct_info.fields:
+        logger.error(f"Field '{field_name}' not found in struct '{struct_type}'")
+        return
+
+    # Get field pointer and evaluate value
+    field_ptr = struct_info.gep(builder, local_sym_tab[var_name].var, field_name)
+    val = eval_expr(
+        func, module, builder, rval, local_sym_tab, map_sym_tab, structs_sym_tab
+    )
+
+    if val is None:
+        logger.error(f"Failed to evaluate value for {var_name}.{field_name}")
+        return
+
+    # TODO: Handle string assignment to char array (not a priority)
+    field_type = struct_info.field_type(field_name)
+    if isinstance(field_type, ir.ArrayType) and val[1] == ir.PointerType(ir.IntType(8)):
+        logger.warning(
+            f"String to char array assignment not implemented for {var_name}.{field_name}"
+        )
+        return
+
+    # Store the value
+    builder.store(val[0], field_ptr)
+    logger.info(f"Assigned to struct field {var_name}.{field_name}")
+
+
+def handle_variable_assignment(
+    func, module, builder, var_name, rval, local_sym_tab, map_sym_tab, structs_sym_tab
+):
+    """Handle single named variable assignment."""
+
+    if var_name not in local_sym_tab:
+        logger.error(f"Variable {var_name} not declared.")
+        return False
+
+    var_ptr = local_sym_tab[var_name].var
+    var_type = local_sym_tab[var_name].ir_type
+
+    # NOTE: Special case for struct initialization
+    if isinstance(rval, ast.Call) and isinstance(rval.func, ast.Name):
+        struct_name = rval.func.id
+        if struct_name in structs_sym_tab and len(rval.args) == 0:
+            struct_info = structs_sym_tab[struct_name]
+            ir_struct = struct_info.ir_type
+
+            builder.store(ir.Constant(ir_struct, None), var_ptr)
+            logger.info(f"Initialized struct {struct_name} for variable {var_name}")
+            return True
+
+    val_result = eval_expr(
+        func, module, builder, rval, local_sym_tab, map_sym_tab, structs_sym_tab
+    )
+    if val_result is None:
+        logger.error(f"Failed to evaluate value for {var_name}")
+        return False
+
+    val, val_type = val_result
+    logger.info(f"Evaluated value for {var_name}: {val} of type {val_type}, {var_type}")
+    if val_type != var_type:
+        if isinstance(val_type, ir.IntType) and isinstance(var_type, ir.IntType):
+            # Allow implicit int widening
+            if val_type.width < var_type.width:
+                val = builder.sext(val, var_type)
+                logger.info(f"Implicitly widened int for variable {var_name}")
+            elif val_type.width > var_type.width:
+                val = builder.trunc(val, var_type)
+                logger.info(f"Implicitly truncated int for variable {var_name}")
+        elif isinstance(val_type, ir.IntType) and isinstance(var_type, ir.PointerType):
+            # NOTE: This is assignment to a PTR_TO_MAP_VALUE_OR_NULL
+            logger.info(
+                f"Creating temporary variable for pointer assignment to {var_name}"
+            )
+            var_ptr_tmp = local_sym_tab[f"{var_name}_tmp"].var
+            builder.store(val, var_ptr_tmp)
+            val = var_ptr_tmp
+        else:
+            logger.error(
+                f"Type mismatch for variable {var_name}: {val_type} vs {var_type}"
+            )
+            return False
+
+    builder.store(val, var_ptr)
+    logger.info(f"Assigned value to variable {var_name}")
+    return True

pythonbpf/binary_ops.py

@@ -3,43 +3,70 @@ from llvmlite import ir
 from logging import Logger
 import logging
 
+from pythonbpf.expr import get_base_type_and_depth, deref_to_depth, eval_expr
+
 logger: Logger = logging.getLogger(__name__)
 
 
-def recursive_dereferencer(var, builder):
-    """dereference until primitive type comes out"""
-    # 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 isinstance(var.type, ir.IntType):
-        return var
-    else:
-        raise TypeError(f"Unsupported type for dereferencing: {var.type}")
-
-
-def get_operand_value(operand, builder, local_sym_tab):
+def get_operand_value(
+    func, module, operand, builder, local_sym_tab, map_sym_tab, structs_sym_tab=None
+):
     """Extract the value from an operand, handling variables and constants."""
+    logger.info(f"Getting operand value for: {ast.dump(operand)}")
     if isinstance(operand, ast.Name):
         if operand.id in local_sym_tab:
-            return recursive_dereferencer(local_sym_tab[operand.id].var, builder)
+            var = local_sym_tab[operand.id].var
+            var_type = var.type
+            base_type, depth = get_base_type_and_depth(var_type)
+            logger.info(f"var is {var}, base_type is {base_type}, depth is {depth}")
+            val = deref_to_depth(func, builder, var, depth)
+            return val
         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)
+            cst = ir.Constant(ir.IntType(64), int(operand.value))
+            return cst
         raise TypeError(f"Unsupported constant type: {type(operand.value)}")
     elif isinstance(operand, ast.BinOp):
-        return handle_binary_op_impl(operand, builder, local_sym_tab)
+        res = handle_binary_op_impl(
+            func, module, operand, builder, local_sym_tab, map_sym_tab, structs_sym_tab
+        )
+        return res
+    else:
+        res = eval_expr(
+            func, module, builder, operand, local_sym_tab, map_sym_tab, structs_sym_tab
+        )
+        if res is None:
+            raise ValueError(f"Failed to evaluate call expression: {operand}")
+        val, _ = res
+        logger.info(f"Evaluated expr to {val} of type {val.type}")
+        base_type, depth = get_base_type_and_depth(val.type)
+        if depth > 0:
+            val = deref_to_depth(func, builder, val, depth)
+        return val
     raise TypeError(f"Unsupported operand type: {type(operand)}")
 
 
-def handle_binary_op_impl(rval, builder, local_sym_tab):
+def handle_binary_op_impl(
+    func, module, rval, builder, local_sym_tab, map_sym_tab, structs_sym_tab=None
+):
     op = rval.op
-    left = get_operand_value(rval.left, builder, local_sym_tab)
-    right = get_operand_value(rval.right, builder, local_sym_tab)
+    left = get_operand_value(
+        func, module, rval.left, builder, local_sym_tab, map_sym_tab, structs_sym_tab
+    )
+    right = get_operand_value(
+        func, module, rval.right, builder, local_sym_tab, map_sym_tab, structs_sym_tab
+    )
     logger.info(f"left is {left}, right is {right}, op is {op}")
 
+    # NOTE: Before doing the operation, if the operands are integers
+    # we always extend them to i64. The assignment to LHS will take
+    # care of truncation if needed.
+    if isinstance(left.type, ir.IntType) and left.type.width < 64:
+        left = builder.sext(left, ir.IntType(64))
+    if isinstance(right.type, ir.IntType) and right.type.width < 64:
+        right = builder.sext(right, ir.IntType(64))
+
     # Map AST operation nodes to LLVM IR builder methods
     op_map = {
         ast.Add: builder.add,
@@ -62,8 +89,19 @@ def handle_binary_op_impl(rval, builder, local_sym_tab):
         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)
+def handle_binary_op(
+    func,
+    module,
+    rval,
+    builder,
+    var_name,
+    local_sym_tab,
+    map_sym_tab,
+    structs_sym_tab=None,
+):
+    result = handle_binary_op_impl(
+        func, module, rval, builder, local_sym_tab, map_sym_tab, structs_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}"

pythonbpf/expr/__init__.py

@@ -1,4 +1,10 @@
 from .expr_pass import eval_expr, handle_expr
-from .type_normalization import convert_to_bool
+from .type_normalization import convert_to_bool, get_base_type_and_depth, deref_to_depth
 
-__all__ = ["eval_expr", "handle_expr", "convert_to_bool"]
+__all__ = [
+    "eval_expr",
+    "handle_expr",
+    "convert_to_bool",
+    "get_base_type_and_depth",
+    "deref_to_depth",
+]

pythonbpf/expr/expr_pass.py

@@ -26,7 +26,7 @@ def _handle_constant_expr(expr: ast.Constant):
     if isinstance(expr.value, int) or isinstance(expr.value, bool):
         return ir.Constant(ir.IntType(64), int(expr.value)), ir.IntType(64)
     else:
-        logger.error("Unsupported constant type")
+        logger.error(f"Unsupported constant type {ast.dump(expr)}")
         return None
 
 
@@ -176,21 +176,28 @@ def _handle_unary_op(
     structs_sym_tab=None,
 ):
     """Handle ast.UnaryOp expressions."""
-    if not isinstance(expr.op, ast.Not):
-        logger.error("Only 'not' unary operator is supported")
+    if not isinstance(expr.op, ast.Not) and not isinstance(expr.op, ast.USub):
+        logger.error("Only 'not' and '-' unary operators are supported")
         return None
 
-    operand = eval_expr(
-        func, module, builder, expr.operand, local_sym_tab, map_sym_tab, structs_sym_tab
+    from pythonbpf.binary_ops import get_operand_value
+
+    operand = get_operand_value(
+        func, module, expr.operand, builder, local_sym_tab, map_sym_tab, structs_sym_tab
     )
     if operand is None:
         logger.error("Failed to evaluate operand for unary operation")
         return None
 
-    operand_val, operand_type = operand
-    true_const = ir.Constant(ir.IntType(1), 1)
-    result = builder.xor(convert_to_bool(builder, operand_val), true_const)
-    return result, ir.IntType(1)
+    if isinstance(expr.op, ast.Not):
+        true_const = ir.Constant(ir.IntType(1), 1)
+        result = builder.xor(convert_to_bool(builder, operand), true_const)
+        return result, ir.IntType(1)
+    elif isinstance(expr.op, ast.USub):
+        # Multiply by -1
+        neg_one = ir.Constant(ir.IntType(64), -1)
+        result = builder.mul(operand, neg_one)
+        return result, ir.IntType(64)
 
 
 def _handle_and_op(func, builder, expr, local_sym_tab, map_sym_tab, structs_sym_tab):
@@ -402,7 +409,16 @@ def eval_expr(
     elif isinstance(expr, ast.BinOp):
         from pythonbpf.binary_ops import handle_binary_op
 
-        return handle_binary_op(expr, builder, None, local_sym_tab)
+        return handle_binary_op(
+            func,
+            module,
+            expr,
+            builder,
+            None,
+            local_sym_tab,
+            map_sym_tab,
+            structs_sym_tab,
+        )
     elif isinstance(expr, ast.Compare):
         return _handle_compare(
             func, module, builder, expr, local_sym_tab, map_sym_tab, structs_sym_tab

pythonbpf/expr/type_normalization.py

@@ -16,7 +16,7 @@ COMPARISON_OPS = {
 }
 
 
-def _get_base_type_and_depth(ir_type):
+def get_base_type_and_depth(ir_type):
     """Get the base type for pointer types."""
     cur_type = ir_type
     depth = 0
@@ -26,7 +26,7 @@ def _get_base_type_and_depth(ir_type):
     return cur_type, depth
 
 
-def _deref_to_depth(func, builder, val, target_depth):
+def deref_to_depth(func, builder, val, target_depth):
     """Dereference a pointer to a certain depth."""
 
     cur_val = val
@@ -88,13 +88,13 @@ def _normalize_types(func, builder, lhs, rhs):
         logger.error(f"Type mismatch: {lhs.type} vs {rhs.type}")
         return None, None
     else:
-        lhs_base, lhs_depth = _get_base_type_and_depth(lhs.type)
-        rhs_base, rhs_depth = _get_base_type_and_depth(rhs.type)
+        lhs_base, lhs_depth = get_base_type_and_depth(lhs.type)
+        rhs_base, rhs_depth = get_base_type_and_depth(rhs.type)
         if lhs_base == rhs_base:
             if lhs_depth < rhs_depth:
-                rhs = _deref_to_depth(func, builder, rhs, rhs_depth - lhs_depth)
+                rhs = deref_to_depth(func, builder, rhs, rhs_depth - lhs_depth)
             elif rhs_depth < lhs_depth:
-                lhs = _deref_to_depth(func, builder, lhs, lhs_depth - rhs_depth)
+                lhs = deref_to_depth(func, builder, lhs, lhs_depth - rhs_depth)
             return _normalize_types(func, builder, lhs, rhs)
 
 

pythonbpf/functions/functions_pass.py

@@ -1,13 +1,18 @@
 from llvmlite import ir
 import ast
 import logging
-from typing import Any
-from dataclasses import dataclass
 
-from pythonbpf.helper import HelperHandlerRegistry, handle_helper_call
+from pythonbpf.helper import (
+    HelperHandlerRegistry,
+    reset_scratch_pool,
+)
 from pythonbpf.type_deducer import ctypes_to_ir
-from pythonbpf.binary_ops import handle_binary_op
 from pythonbpf.expr import eval_expr, handle_expr, convert_to_bool
+from pythonbpf.assign_pass import (
+    handle_variable_assignment,
+    handle_struct_field_assignment,
+)
+from pythonbpf.allocation_pass import handle_assign_allocation, allocate_temp_pool
 
 from .return_utils import _handle_none_return, _handle_xdp_return, _is_xdp_name
 
@@ -15,18 +20,6 @@ from .return_utils import _handle_none_return, _handle_xdp_return, _is_xdp_name
 logger = logging.getLogger(__name__)
 
 
-@dataclass
-class LocalSymbol:
-    var: ir.AllocaInstr
-    ir_type: ir.Type
-    metadata: Any = None
-
-    def __iter__(self):
-        yield self.var
-        yield self.ir_type
-        yield self.metadata
-
-
 def get_probe_string(func_node):
     """Extract the probe string from the decorator of the function node."""
     # TODO: right now we have the whole string in the section decorator
@@ -48,196 +41,49 @@ def handle_assign(
     func, module, builder, stmt, map_sym_tab, local_sym_tab, structs_sym_tab
 ):
     """Handle assignment statements in the function body."""
-    if len(stmt.targets) != 1:
-        logger.info("Unsupported multiassignment")
-        return
 
-    num_types = ("c_int32", "c_int64", "c_uint32", "c_uint64")
+    # TODO: Support this later
+    # GH #37
+    if len(stmt.targets) != 1:
+        logger.error("Multi-target assignment is not supported for now")
+        return
 
     target = stmt.targets[0]
-    logger.info(f"Handling assignment to {ast.dump(target)}")
-    if not isinstance(target, ast.Name) and not isinstance(target, ast.Attribute):
-        logger.info("Unsupported assignment target")
-        return
-    var_name = target.id if isinstance(target, ast.Name) else target.value.id
     rval = stmt.value
+
+    if isinstance(target, ast.Name):
+        # NOTE: Simple variable assignment case: x = 5
+        var_name = target.id
+        result = handle_variable_assignment(
+            func,
+            module,
+            builder,
+            var_name,
+            rval,
+            local_sym_tab,
+            map_sym_tab,
+            structs_sym_tab,
+        )
+        if not result:
+            logger.error(f"Failed to handle assignment to {var_name}")
+        return
+
     if isinstance(target, ast.Attribute):
-        # struct field assignment
-        field_name = target.attr
-        if var_name in local_sym_tab:
-            struct_type = local_sym_tab[var_name].metadata
-            struct_info = structs_sym_tab[struct_type]
-            if field_name in struct_info.fields:
-                field_ptr = struct_info.gep(
-                    builder, local_sym_tab[var_name].var, field_name
-                )
-                val = eval_expr(
-                    func,
-                    module,
-                    builder,
-                    rval,
-                    local_sym_tab,
-                    map_sym_tab,
-                    structs_sym_tab,
-                )
-                if isinstance(struct_info.field_type(field_name), ir.ArrayType) and val[
-                    1
-                ] == ir.PointerType(ir.IntType(8)):
-                    # TODO: Figure it out, not a priority rn
-                    # Special case for string assignment to char array
-                    # str_len = struct_info["field_types"][field_idx].count
-                    # assign_string_to_array(builder, field_ptr, val[0], str_len)
-                    # print(f"Assigned to struct field {var_name}.{field_name}")
-                    pass
-                if val is None:
-                    logger.info("Failed to evaluate struct field assignment")
-                    return
-                logger.info(field_ptr)
-                builder.store(val[0], field_ptr)
-                logger.info(f"Assigned to struct field {var_name}.{field_name}")
-                return
-    elif isinstance(rval, ast.Constant):
-        if isinstance(rval.value, bool):
-            if rval.value:
-                builder.store(
-                    ir.Constant(ir.IntType(1), 1), local_sym_tab[var_name].var
-                )
-            else:
-                builder.store(
-                    ir.Constant(ir.IntType(1), 0), local_sym_tab[var_name].var
-                )
-            logger.info(f"Assigned constant {rval.value} to {var_name}")
-        elif isinstance(rval.value, int):
-            # Assume c_int64 for now
-            # var = builder.alloca(ir.IntType(64), name=var_name)
-            # var.align = 8
-            builder.store(
-                ir.Constant(ir.IntType(64), rval.value), local_sym_tab[var_name].var
-            )
-            logger.info(f"Assigned constant {rval.value} to {var_name}")
-        elif isinstance(rval.value, str):
-            str_val = rval.value.encode("utf-8") + b"\x00"
-            str_const = ir.Constant(
-                ir.ArrayType(ir.IntType(8), len(str_val)), bytearray(str_val)
-            )
-            global_str = ir.GlobalVariable(
-                module, str_const.type, name=f"{var_name}_str"
-            )
-            global_str.linkage = "internal"
-            global_str.global_constant = True
-            global_str.initializer = str_const
-            str_ptr = builder.bitcast(global_str, ir.PointerType(ir.IntType(8)))
-            builder.store(str_ptr, local_sym_tab[var_name].var)
-            logger.info(f"Assigned string constant '{rval.value}' to {var_name}")
-        else:
-            logger.info("Unsupported constant type")
-    elif isinstance(rval, ast.Call):
-        if isinstance(rval.func, ast.Name):
-            call_type = rval.func.id
-            logger.info(f"Assignment call type: {call_type}")
-            if (
-                call_type in num_types
-                and len(rval.args) == 1
-                and isinstance(rval.args[0], ast.Constant)
-                and isinstance(rval.args[0].value, int)
-            ):
-                ir_type = ctypes_to_ir(call_type)
-                # var = builder.alloca(ir_type, name=var_name)
-                # var.align = ir_type.width // 8
-                builder.store(
-                    ir.Constant(ir_type, rval.args[0].value),
-                    local_sym_tab[var_name].var,
-                )
-                logger.info(
-                    f"Assigned {call_type} constant {rval.args[0].value} to {var_name}"
-                )
-            elif HelperHandlerRegistry.has_handler(call_type):
-                # var = builder.alloca(ir.IntType(64), name=var_name)
-                # var.align = 8
-                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)
-                logger.info(f"Assigned constant {rval.func.id} to {var_name}")
-            elif call_type == "deref" and len(rval.args) == 1:
-                logger.info(f"Handling deref assignment {ast.dump(rval)}")
-                val = eval_expr(
-                    func,
-                    module,
-                    builder,
-                    rval,
-                    local_sym_tab,
-                    map_sym_tab,
-                    structs_sym_tab,
-                )
-                if val is None:
-                    logger.info("Failed to evaluate deref argument")
-                    return
-                logger.info(f"Dereferenced value: {val}, storing in {var_name}")
-                builder.store(val[0], local_sym_tab[var_name].var)
-                logger.info(f"Dereferenced and assigned to {var_name}")
-            elif call_type in structs_sym_tab and len(rval.args) == 0:
-                struct_info = structs_sym_tab[call_type]
-                ir_type = struct_info.ir_type
-                # var = builder.alloca(ir_type, name=var_name)
-                # Null init
-                builder.store(ir.Constant(ir_type, None), local_sym_tab[var_name].var)
-                logger.info(f"Assigned struct {call_type} to {var_name}")
-            else:
-                logger.info(f"Unsupported assignment call type: {call_type}")
-        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(
-                rval.func.value.func, ast.Name
-            ):
-                map_name = rval.func.value.func.id
-                method_name = rval.func.attr
-                if map_name in map_sym_tab:
-                    if HelperHandlerRegistry.has_handler(method_name):
-                        val = handle_helper_call(
-                            rval,
-                            module,
-                            builder,
-                            func,
-                            local_sym_tab,
-                            map_sym_tab,
-                            structs_sym_tab,
-                        )
-                        # var = builder.alloca(ir.IntType(64), name=var_name)
-                        # var.align = 8
-                        builder.store(val[0], local_sym_tab[var_name].var)
-            else:
-                logger.info("Unsupported assignment call structure")
-        else:
-            logger.info("Unsupported assignment call function type")
-    elif isinstance(rval, ast.BinOp):
-        handle_binary_op(rval, builder, var_name, local_sym_tab)
-    else:
-        logger.info("Unsupported assignment value type")
+        # NOTE: Struct field assignment case: pkt.field = value
+        handle_struct_field_assignment(
+            func,
+            module,
+            builder,
+            target,
+            rval,
+            local_sym_tab,
+            map_sym_tab,
+            structs_sym_tab,
+        )
+        return
+
+    # Unsupported target type
+    logger.error(f"Unsupported assignment target: {ast.dump(target)}")
 
 
 def handle_cond(
@@ -330,6 +176,7 @@ def process_stmt(
     ret_type=ir.IntType(64),
 ):
     logger.info(f"Processing statement: {ast.dump(stmt)}")
+    reset_scratch_pool()
     if isinstance(stmt, ast.Expr):
         handle_expr(
             func,
@@ -360,119 +207,107 @@ def process_stmt(
     return did_return
 
 
+def handle_if_allocation(
+    module, builder, stmt, func, ret_type, map_sym_tab, local_sym_tab, structs_sym_tab
+):
+    """Recursively handle allocations in if/else branches."""
+    if stmt.body:
+        allocate_mem(
+            module,
+            builder,
+            stmt.body,
+            func,
+            ret_type,
+            map_sym_tab,
+            local_sym_tab,
+            structs_sym_tab,
+        )
+    if stmt.orelse:
+        allocate_mem(
+            module,
+            builder,
+            stmt.orelse,
+            func,
+            ret_type,
+            map_sym_tab,
+            local_sym_tab,
+            structs_sym_tab,
+        )
+
+
+def count_temps_in_call(call_node, local_sym_tab):
+    """Count the number of temporary variables needed for a function call."""
+
+    count = 0
+    is_helper = False
+
+    # NOTE: We exclude print calls for now
+    if isinstance(call_node.func, ast.Name):
+        if (
+            HelperHandlerRegistry.has_handler(call_node.func.id)
+            and call_node.func.id != "print"
+        ):
+            is_helper = True
+    elif isinstance(call_node.func, ast.Attribute):
+        if HelperHandlerRegistry.has_handler(call_node.func.attr):
+            is_helper = True
+
+    if not is_helper:
+        return 0
+
+    for arg in call_node.args:
+        # NOTE: Count all non-name arguments
+        # For struct fields, if it is being passed as an argument,
+        # The struct object should already exist in the local_sym_tab
+        if not isinstance(arg, ast.Name) and not (
+            isinstance(arg, ast.Attribute) and arg.value.id in local_sym_tab
+        ):
+            count += 1
+
+    return count
+
+
 def allocate_mem(
     module, builder, body, func, ret_type, map_sym_tab, local_sym_tab, structs_sym_tab
 ):
-    for stmt in body:
-        has_metadata = False
-        if isinstance(stmt, ast.If):
-            if stmt.body:
-                local_sym_tab = allocate_mem(
-                    module,
-                    builder,
-                    stmt.body,
-                    func,
-                    ret_type,
-                    map_sym_tab,
-                    local_sym_tab,
-                    structs_sym_tab,
-                )
-            if stmt.orelse:
-                local_sym_tab = allocate_mem(
-                    module,
-                    builder,
-                    stmt.orelse,
-                    func,
-                    ret_type,
-                    map_sym_tab,
-                    local_sym_tab,
-                    structs_sym_tab,
-                )
-        elif isinstance(stmt, ast.Assign):
-            if len(stmt.targets) != 1:
-                logger.info("Unsupported multiassignment")
-                continue
-            target = stmt.targets[0]
-            if not isinstance(target, ast.Name):
-                logger.info("Unsupported assignment target")
-                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
-                    if call_type in ("c_int32", "c_int64", "c_uint32", "c_uint64"):
-                        ir_type = ctypes_to_ir(call_type)
-                        var = builder.alloca(ir_type, name=var_name)
-                        var.align = ir_type.width // 8
-                        logger.info(
-                            f"Pre-allocated variable {var_name} of type {call_type}"
-                        )
-                    elif HelperHandlerRegistry.has_handler(call_type):
-                        # Assume return type is int64 for now
-                        ir_type = ir.IntType(64)
-                        var = builder.alloca(ir_type, name=var_name)
-                        var.align = ir_type.width // 8
-                        logger.info(f"Pre-allocated variable {var_name} for helper")
-                    elif call_type == "deref" and len(rval.args) == 1:
-                        # Assume return type is int64 for now
-                        ir_type = ir.IntType(64)
-                        var = builder.alloca(ir_type, name=var_name)
-                        var.align = ir_type.width // 8
-                        logger.info(f"Pre-allocated variable {var_name} for deref")
-                    elif call_type in structs_sym_tab:
-                        struct_info = structs_sym_tab[call_type]
-                        ir_type = struct_info.ir_type
-                        var = builder.alloca(ir_type, name=var_name)
-                        has_metadata = True
-                        logger.info(
-                            f"Pre-allocated variable {var_name} for struct {call_type}"
-                        )
-                elif isinstance(rval.func, ast.Attribute):
-                    ir_type = ir.PointerType(ir.IntType(64))
-                    var = builder.alloca(ir_type, name=var_name)
-                    # var.align = ir_type.width // 8
-                    logger.info(f"Pre-allocated variable {var_name} for map")
-                else:
-                    logger.info("Unsupported assignment call function type")
-                    continue
-            elif isinstance(rval, ast.Constant):
-                if isinstance(rval.value, bool):
-                    ir_type = ir.IntType(1)
-                    var = builder.alloca(ir_type, name=var_name)
-                    var.align = 1
-                    logger.info(f"Pre-allocated variable {var_name} of type c_bool")
-                elif isinstance(rval.value, int):
-                    # Assume c_int64 for now
-                    ir_type = ir.IntType(64)
-                    var = builder.alloca(ir_type, name=var_name)
-                    var.align = ir_type.width // 8
-                    logger.info(f"Pre-allocated variable {var_name} of type c_int64")
-                elif isinstance(rval.value, str):
-                    ir_type = ir.PointerType(ir.IntType(8))
-                    var = builder.alloca(ir_type, name=var_name)
-                    var.align = 8
-                    logger.info(f"Pre-allocated variable {var_name} of type string")
-                else:
-                    logger.info("Unsupported constant type")
-                    continue
-            elif isinstance(rval, ast.BinOp):
-                # Assume c_int64 for now
-                ir_type = ir.IntType(64)
-                var = builder.alloca(ir_type, name=var_name)
-                var.align = ir_type.width // 8
-                logger.info(f"Pre-allocated variable {var_name} of type c_int64")
-            else:
-                logger.info("Unsupported assignment value type")
-                continue
+    max_temps_needed = 0
+
+    def update_max_temps_for_stmt(stmt):
+        nonlocal max_temps_needed
+        temps_needed = 0
+
+        if isinstance(stmt, ast.If):
+            for s in stmt.body:
+                update_max_temps_for_stmt(s)
+            for s in stmt.orelse:
+                update_max_temps_for_stmt(s)
+            return
+
+        for node in ast.walk(stmt):
+            if isinstance(node, ast.Call):
+                temps_needed += count_temps_in_call(node, local_sym_tab)
+        max_temps_needed = max(max_temps_needed, temps_needed)
+
+    for stmt in body:
+        update_max_temps_for_stmt(stmt)
+
+        # Handle allocations
+        if isinstance(stmt, ast.If):
+            handle_if_allocation(
+                module,
+                builder,
+                stmt,
+                func,
+                ret_type,
+                map_sym_tab,
+                local_sym_tab,
+                structs_sym_tab,
+            )
+        elif isinstance(stmt, ast.Assign):
+            handle_assign_allocation(builder, stmt, local_sym_tab, structs_sym_tab)
+
+    allocate_temp_pool(builder, max_temps_needed, local_sym_tab)
 
-            if has_metadata:
-                local_sym_tab[var_name] = LocalSymbol(var, ir_type, call_type)
-            else:
-                local_sym_tab[var_name] = LocalSymbol(var, ir_type)
     return local_sym_tab
 
 

pythonbpf/helper/__init__.py

@@ -1,9 +1,10 @@
-from .helper_utils import HelperHandlerRegistry
+from .helper_utils import HelperHandlerRegistry, reset_scratch_pool
 from .bpf_helper_handler import handle_helper_call
 from .helpers import ktime, pid, deref, XDP_DROP, XDP_PASS
 
 __all__ = [
     "HelperHandlerRegistry",
+    "reset_scratch_pool",
     "handle_helper_call",
     "ktime",
     "pid",

pythonbpf/helper/bpf_helper_handler.py

@@ -34,6 +34,7 @@ def bpf_ktime_get_ns_emitter(
     func,
     local_sym_tab=None,
     struct_sym_tab=None,
+    map_sym_tab=None,
 ):
     """
     Emit LLVM IR for bpf_ktime_get_ns helper function call.
@@ -56,6 +57,7 @@ def bpf_map_lookup_elem_emitter(
     func,
     local_sym_tab=None,
     struct_sym_tab=None,
+    map_sym_tab=None,
 ):
     """
     Emit LLVM IR for bpf_map_lookup_elem helper function call.
@@ -64,11 +66,17 @@ def bpf_map_lookup_elem_emitter(
         raise ValueError(
             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)
+    key_ptr = get_or_create_ptr_from_arg(
+        func, module, call.args[0], builder, local_sym_tab, map_sym_tab, struct_sym_tab
+    )
     map_void_ptr = builder.bitcast(map_ptr, ir.PointerType())
 
+    # TODO: I have changed the return type to i64*, as we are
+    # allocating space for that type in allocate_mem. This is
+    # temporary, and we will honour other widths later. But this
+    # allows us to have cool binary ops on the returned value.
     fn_type = ir.FunctionType(
-        ir.PointerType(),  # Return type: void*
+        ir.PointerType(ir.IntType(64)),  # Return type: void*
         [ir.PointerType(), ir.PointerType()],  # Args: (void*, void*)
         var_arg=False,
     )
@@ -91,6 +99,7 @@ def bpf_printk_emitter(
     func,
     local_sym_tab=None,
     struct_sym_tab=None,
+    map_sym_tab=None,
 ):
     """Emit LLVM IR for bpf_printk helper function call."""
     if not hasattr(func, "_fmt_counter"):
@@ -138,6 +147,7 @@ def bpf_map_update_elem_emitter(
     func,
     local_sym_tab=None,
     struct_sym_tab=None,
+    map_sym_tab=None,
 ):
     """
     Emit LLVM IR for bpf_map_update_elem helper function call.
@@ -152,8 +162,12 @@ def bpf_map_update_elem_emitter(
     value_arg = call.args[1]
     flags_arg = call.args[2] if len(call.args) > 2 else None
 
-    key_ptr = get_or_create_ptr_from_arg(key_arg, builder, local_sym_tab)
-    value_ptr = get_or_create_ptr_from_arg(value_arg, builder, local_sym_tab)
+    key_ptr = get_or_create_ptr_from_arg(
+        func, module, key_arg, builder, local_sym_tab, map_sym_tab, struct_sym_tab
+    )
+    value_ptr = get_or_create_ptr_from_arg(
+        func, module, value_arg, builder, local_sym_tab, map_sym_tab, struct_sym_tab
+    )
     flags_val = get_flags_val(flags_arg, builder, local_sym_tab)
 
     map_void_ptr = builder.bitcast(map_ptr, ir.PointerType())
@@ -188,6 +202,7 @@ def bpf_map_delete_elem_emitter(
     func,
     local_sym_tab=None,
     struct_sym_tab=None,
+    map_sym_tab=None,
 ):
     """
     Emit LLVM IR for bpf_map_delete_elem helper function call.
@@ -197,7 +212,9 @@ def bpf_map_delete_elem_emitter(
         raise ValueError(
             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)
+    key_ptr = get_or_create_ptr_from_arg(
+        func, module, call.args[0], builder, local_sym_tab, map_sym_tab, struct_sym_tab
+    )
     map_void_ptr = builder.bitcast(map_ptr, ir.PointerType())
 
     # Define function type for bpf_map_delete_elem
@@ -225,6 +242,7 @@ def bpf_get_current_pid_tgid_emitter(
     func,
     local_sym_tab=None,
     struct_sym_tab=None,
+    map_sym_tab=None,
 ):
     """
     Emit LLVM IR for bpf_get_current_pid_tgid helper function call.
@@ -251,6 +269,7 @@ def bpf_perf_event_output_handler(
     func,
     local_sym_tab=None,
     struct_sym_tab=None,
+    map_sym_tab=None,
 ):
     if len(call.args) != 1:
         raise ValueError(
@@ -315,6 +334,7 @@ def handle_helper_call(
             func,
             local_sym_tab,
             struct_sym_tab,
+            map_sym_tab,
         )
 
     # Handle direct function calls (e.g., print(), ktime())

pythonbpf/helper/helper_utils.py

@@ -3,7 +3,8 @@ import logging
 from collections.abc import Callable
 
 from llvmlite import ir
-from pythonbpf.expr import eval_expr
+from pythonbpf.expr import eval_expr, get_base_type_and_depth, deref_to_depth
+from pythonbpf.binary_ops import get_operand_value
 
 logger = logging.getLogger(__name__)
 
@@ -34,6 +35,41 @@ class HelperHandlerRegistry:
         return helper_name in cls._handlers
 
 
+class ScratchPoolManager:
+    """Manage the temporary helper variables in local_sym_tab"""
+
+    def __init__(self):
+        self._counter = 0
+
+    @property
+    def counter(self):
+        return self._counter
+
+    def reset(self):
+        self._counter = 0
+        logger.debug("Scratch pool counter reset to 0")
+
+    def get_next_temp(self, local_sym_tab):
+        temp_name = f"__helper_temp_{self._counter}"
+        self._counter += 1
+
+        if temp_name not in local_sym_tab:
+            raise ValueError(
+                f"Scratch pool exhausted or inadequate: {temp_name}. "
+                f"Current counter: {self._counter}"
+            )
+
+        return local_sym_tab[temp_name].var, temp_name
+
+
+_temp_pool_manager = ScratchPoolManager()  # Singleton instance
+
+
+def reset_scratch_pool():
+    """Reset the scratch pool counter"""
+    _temp_pool_manager.reset()
+
+
 def get_var_ptr_from_name(var_name, local_sym_tab):
     """Get a pointer to a variable from the symbol table."""
     if local_sym_tab and var_name in local_sym_tab:
@@ -41,27 +77,41 @@ def get_var_ptr_from_name(var_name, local_sym_tab):
     raise ValueError(f"Variable '{var_name}' not found in local symbol table")
 
 
-def create_int_constant_ptr(value, builder, int_width=64):
+def create_int_constant_ptr(value, builder, local_sym_tab, int_width=64):
     """Create a pointer to an integer constant."""
+
     # Default to 64-bit integer
-    int_type = ir.IntType(int_width)
-    ptr = builder.alloca(int_type)
-    ptr.align = int_type.width // 8
-    builder.store(ir.Constant(int_type, value), ptr)
+    ptr, temp_name = _temp_pool_manager.get_next_temp(local_sym_tab)
+    logger.info(f"Using temp variable '{temp_name}' for int constant {value}")
+    const_val = ir.Constant(ir.IntType(int_width), value)
+    builder.store(const_val, ptr)
     return ptr
 
 
-def get_or_create_ptr_from_arg(arg, builder, local_sym_tab):
+def get_or_create_ptr_from_arg(
+    func, module, arg, builder, local_sym_tab, map_sym_tab, struct_sym_tab=None
+):
     """Extract or create pointer from the call arguments."""
 
     if isinstance(arg, ast.Name):
         ptr = get_var_ptr_from_name(arg.id, local_sym_tab)
     elif isinstance(arg, ast.Constant) and isinstance(arg.value, int):
-        ptr = create_int_constant_ptr(arg.value, builder)
+        ptr = create_int_constant_ptr(arg.value, builder, local_sym_tab)
     else:
-        raise NotImplementedError(
-            "Only simple variable names are supported as args in map helpers."
+        # Evaluate the expression and store the result in a temp variable
+        val = get_operand_value(
+            func, module, arg, builder, local_sym_tab, map_sym_tab, struct_sym_tab
         )
+        if val is None:
+            raise ValueError("Failed to evaluate expression for helper arg.")
+
+        # NOTE: We assume the result is an int64 for now
+        # if isinstance(arg, ast.Attribute):
+        # return val
+        ptr, temp_name = _temp_pool_manager.get_next_temp(local_sym_tab)
+        logger.info(f"Using temp variable '{temp_name}' for expression result")
+        builder.store(val, ptr)
+
     return ptr
 
 
@@ -224,10 +274,27 @@ def _populate_fval(ftype, node, fmt_parts, exprs):
             raise NotImplementedError(
                 f"Unsupported integer width in f-string: {ftype.width}"
             )
-    elif ftype == ir.PointerType(ir.IntType(8)):
-        # NOTE: We assume i8* is a string
-        fmt_parts.append("%s")
-        exprs.append(node)
+    elif isinstance(ftype, ir.PointerType):
+        target, depth = get_base_type_and_depth(ftype)
+        if isinstance(target, ir.IntType):
+            if target.width == 64:
+                fmt_parts.append("%lld")
+                exprs.append(node)
+            elif target.width == 32:
+                fmt_parts.append("%d")
+                exprs.append(node)
+            elif target.width == 8 and depth == 1:
+                # NOTE: Assume i8* is a string
+                fmt_parts.append("%s")
+                exprs.append(node)
+            else:
+                raise NotImplementedError(
+                    f"Unsupported pointer target type in f-string: {target}"
+                )
+        else:
+            raise NotImplementedError(
+                f"Unsupported pointer target type in f-string: {target}"
+            )
     else:
         raise NotImplementedError(f"Unsupported field type in f-string: {ftype}")
 
@@ -264,7 +331,20 @@ def _prepare_expr_args(expr, func, module, builder, local_sym_tab, struct_sym_ta
 
     if val:
         if isinstance(val.type, ir.PointerType):
-            val = builder.ptrtoint(val, ir.IntType(64))
+            target, depth = get_base_type_and_depth(val.type)
+            if isinstance(target, ir.IntType):
+                if target.width >= 32:
+                    val = deref_to_depth(func, builder, val, depth)
+                    val = builder.sext(val, ir.IntType(64))
+                elif target.width == 8 and depth == 1:
+                    # NOTE: i8* is string, no need to deref
+                    pass
+
+            else:
+                logger.warning(
+                    "Only int and ptr supported in bpf_printk args. Others default to 0."
+                )
+                val = ir.Constant(ir.IntType(64), 0)
         elif isinstance(val.type, ir.IntType):
             if val.type.width < 64:
                 val = builder.sext(val, ir.IntType(64))

tests/failing_tests/assign/retype.py

@@ -0,0 +1,39 @@
+from pythonbpf import bpf, map, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64, c_uint64
+from pythonbpf.maps import HashMap
+
+
+# NOTE: This example tries to reinterpret the variable `x` to a different type.
+# We do not allow this for now, as stack allocations are typed and have to be
+# done in the first basic block. Allowing re-interpretation would require
+# re-allocation of stack space (possibly in a new basic block), which is not
+# supported in eBPF yet.
+# We can allow bitcasts in cases where the width of the types is the same in
+# the future. But for now, we do not allow any re-interpretation of variables.
+
+@bpf
+@map
+def last() -> HashMap:
+    return HashMap(key=c_uint64, value=c_uint64, max_entries=3)
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    last.update(0, 1)
+    x = last.lookup(0)
+    x = 20
+    if x == 2:
+        print("Hello, World!")
+    else:
+        print("Goodbye, World!")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/assign/comprehensive.py

@@ -0,0 +1,69 @@
+from pythonbpf import bpf, map, section, bpfglobal, compile, struct
+from ctypes import c_void_p, c_int64, c_int32, c_uint64
+from pythonbpf.maps import HashMap
+from pythonbpf.helper import ktime
+
+
+# NOTE: This is a comprehensive test combining struct, helper, and map features
+# Please note that at line 50, though we have used an absurd expression to test
+# the compiler, it is recommended to use named variables to reduce the amount of
+# scratch space that needs to be allocated.
+
+@bpf
+@struct
+class data_t:
+    pid: c_uint64
+    ts: c_uint64
+
+
+@bpf
+@map
+def last() -> HashMap:
+    return HashMap(key=c_uint64, value=c_uint64, max_entries=3)
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    dat = data_t()
+    dat.pid = 123
+    dat.pid = dat.pid + 1
+    print(f"pid is {dat.pid}")
+    tu = 9
+    last.update(0, tu)
+    last.update(1, -last.lookup(0))
+    x = last.lookup(0)
+    print(f"Map value at index 0: {x}")
+    x = x + c_int32(1)
+    print(f"x after adding 32-bit 1 is {x}")
+    x = ktime() - 121
+    print(f"ktime - 121 is {x}")
+    x = last.lookup(0)
+    x = x + 1
+    print(f"x is {x}")
+    if x == 10:
+        jat = data_t()
+        jat.ts = 456
+        print(f"Hello, World!, ts is {jat.ts}")
+        a = last.lookup(0)
+        print(f"a is {a}")
+        last.update(9, 9)
+        last.update(0, last.lookup(last.lookup(0)) +
+                    last.lookup(last.lookup(0)) + last.lookup(last.lookup(0)))
+        z = last.lookup(0)
+        print(f"new map val at index 0 is {z}")
+    else:
+        a = last.lookup(0)
+        print("Goodbye, World!")
+    c = last.lookup(1 - 1)
+    print(f"c is {c}")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/assign/cst_var_binop.py

@@ -0,0 +1,27 @@
+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:
+    x = 1
+    print(f"Initial x: {x}")
+    a = 20
+    x = a
+    print(f"Updated x with a: {x}")
+    x = (x + x) * 3
+    if x == 2:
+        print("Hello, World!")
+    else:
+        print(f"Goodbye, World! {x}")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/assign/helper.py

@@ -0,0 +1,34 @@
+from pythonbpf import bpf, map, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64, c_uint64
+from pythonbpf.maps import HashMap
+
+# NOTE: An example of i64** assignment with binops on the RHS
+
+
+@bpf
+@map
+def last() -> HashMap:
+    return HashMap(key=c_uint64, value=c_uint64, max_entries=3)
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    last.update(0, 1)
+    x = last.lookup(0)
+    print(f"{x}")
+    x = x + 1
+    if x == 2:
+        print("Hello, World!")
+    else:
+        print("Goodbye, World!")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/passing_tests/assign/struct_and_helper_binops.py

@@ -0,0 +1,40 @@
+from pythonbpf import bpf, section, bpfglobal, compile, struct
+from ctypes import c_void_p, c_int64, c_uint64
+from pythonbpf.helper import ktime
+
+
+@bpf
+@struct
+class data_t:
+    pid: c_uint64
+    ts: c_uint64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    dat = data_t()
+    dat.pid = 123
+    dat.pid = dat.pid + 1
+    print(f"pid is {dat.pid}")
+    x = ktime() - 121
+    print(f"ktime is {x}")
+    x = 1
+    x = x + 1
+    print(f"x is {x}")
+    if x == 2:
+        jat = data_t()
+        jat.ts = 456
+        print(f"Hello, World!, ts is {jat.ts}")
+    else:
+        print("Goodbye, World!")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()