Move binop handling logic to expr_pass, remove delayed imports of get_operand_value

Author: r41k0u

pythonbpf/binary_ops.py

@@ -1,4 +1,4 @@
-from .expr_pass import eval_expr, handle_expr
+from .expr_pass import eval_expr, handle_expr, get_operand_value
 from .type_normalization import convert_to_bool, get_base_type_and_depth, deref_to_depth
 
 __all__ = [
@@ -7,4 +7,5 @@
     "convert_to_bool",
     "get_base_type_and_depth",
     "deref_to_depth",
+    "get_operand_value",
 ]

pythonbpf/expr/__init__.py

@@ -5,11 +5,118 @@
 from typing import Dict
 
 from pythonbpf.type_deducer import ctypes_to_ir, is_ctypes
-from .type_normalization import convert_to_bool, handle_comparator
+from .type_normalization import (
+    convert_to_bool,
+    handle_comparator,
+    get_base_type_and_depth,
+    deref_to_depth,
+)
 
 logger: Logger = logging.getLogger(__name__)
 
 
+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:
+            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):
+            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):
+        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(
+    func, module, rval, builder, local_sym_tab, map_sym_tab, structs_sym_tab=None
+):
+    op = rval.op
+    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,
+        ast.Sub: builder.sub,
+        ast.Mult: builder.mul,
+        ast.Div: builder.sdiv,
+        ast.Mod: builder.srem,
+        ast.LShift: builder.shl,
+        ast.RShift: builder.lshr,
+        ast.BitOr: builder.or_,
+        ast.BitXor: builder.xor,
+        ast.BitAnd: builder.and_,
+        ast.FloorDiv: builder.udiv,
+    }
+
+    if type(op) in op_map:
+        result = op_map[type(op)](left, right)
+        return result
+    else:
+        raise SyntaxError("Unsupported binary operation")
+
+
+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}"
+        )
+        builder.store(result, local_sym_tab[var_name].var)
+    return result, result.type
+
+
 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:
@@ -194,8 +301,6 @@ def _handle_unary_op(
         logger.error("Only 'not' and '-' unary operators are supported")
         return None
 
-    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
     )
@@ -421,9 +526,7 @@ def eval_expr(
     elif isinstance(expr, ast.Attribute):
         return _handle_attribute_expr(expr, local_sym_tab, structs_sym_tab, builder)
     elif isinstance(expr, ast.BinOp):
-        from pythonbpf.binary_ops import handle_binary_op
-
-        return handle_binary_op(
+        return _handle_binary_op(
             func,
             module,
             expr,

pythonbpf/expr/expr_pass.py

@@ -3,8 +3,12 @@
 from collections.abc import Callable
 
 from llvmlite import ir
-from pythonbpf.expr import eval_expr, get_base_type_and_depth, deref_to_depth
-from pythonbpf.binary_ops import get_operand_value
+from pythonbpf.expr import (
+    eval_expr,
+    get_base_type_and_depth,
+    deref_to_depth,
+    get_operand_value,
+)
 
 logger = logging.getLogger(__name__)