Move conditional logic to eval_expr, add _conver_to_bool, add passing bool test

Author: r41k0u

pythonbpf/expr_pass.py

@@ -131,9 +131,35 @@ def _handle_ctypes_call(
     return val
 
 
+def _handle_comparator(builder, op, lhs, rhs):
+    """Handle comparison operations."""
+
+    # NOTE: For now assume same types
+
+    comparison_ops = {
+        ast.Eq: "==",
+        ast.NotEq: "!=",
+        ast.Lt: "<",
+        ast.LtE: "<=",
+        ast.Gt: ">",
+        ast.GtE: ">=",
+    }
+
+    if type(op) not in comparison_ops:
+        logger.error(f"Unsupported comparison operator: {type(op)}")
+        return None
+
+    predicate = comparison_ops[type(op)]
+    result = builder.icmp_signed(predicate, lhs, rhs)
+    logger.debug(f"Comparison result: {result}")
+    return result, ir.IntType(1)
+
+
 def _handle_compare(
     func, module, builder, cond, local_sym_tab, map_sym_tab, structs_sym_tab=None
 ):
+    """Handle ast.Compare expressions."""
+
     if len(cond.ops) != 1 or len(cond.comparators) != 1:
         logger.error("Only single comparisons are supported")
         return None
@@ -162,7 +188,7 @@ def _handle_compare(
 
     lhs, _ = lhs
     rhs, _ = rhs
-    return None
+    return _handle_comparator(builder, cond.ops[0], lhs, rhs)
 
 
 def eval_expr(

pythonbpf/functions/functions_pass.py

@@ -240,12 +240,25 @@ def handle_assign(
         logger.info("Unsupported assignment value type")
 
 
+def _convert_to_bool(builder, val):
+    if val.type == ir.IntType(1):
+        return val
+    if isinstance(val.type, ir.PointerType):
+        zero = ir.Constant(val.type, None)
+    else:
+        zero = ir.Constant(val.type, 0)
+    return builder.icmp_signed("!=", val, zero)
+
+
 def handle_cond(func, module, builder, cond, local_sym_tab, map_sym_tab):
+    if True:
+        val = eval_expr(func, module, builder, cond, local_sym_tab, map_sym_tab)[0]
+        return _convert_to_bool(builder, val)
     if isinstance(cond, ast.Constant):
         if isinstance(cond.value, bool) or isinstance(cond.value, int):
-            return ir.Constant(ir.IntType(1), int(bool(cond.value)))
+            return ir.Constant(ir.IntType(1), int(cond.value))
         else:
-            logger.info("Unsupported constant type in condition")
+            raise ValueError("Unsupported constant type in condition")
             return None
     elif isinstance(cond, ast.Name):
         if cond.id in local_sym_tab:

tests/passing_tests/conditionals/bool.py

@@ -0,0 +1,21 @@
+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:
+    if True:
+        print("Hello, World!")
+    else:
+        print("Goodbye, World!")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()