revert struct reference pointer sizes to i8 to ensure that compiler does not optimize

Author: varun-r-mallya

pythonbpf/codegen.py

@@ -39,7 +39,7 @@ def finalize_module(original_str):
 
 def bpf_passthrough_gen(module):
     i32_ty = ir.IntType(32)
-    ptr_ty = ir.PointerType(ir.IntType(64))
+    ptr_ty = ir.PointerType(ir.IntType(8))
     fnty = ir.FunctionType(ptr_ty, [i32_ty, ptr_ty])
 
     # Declare the intrinsic

pythonbpf/vmlinux_parser/vmlinux_exports_handler.py

@@ -97,7 +97,7 @@ def handle_vmlinux_struct_field(
             globvar_ir, field_data = self.get_field_type(
                 python_type.__name__, field_name
             )
-            builder.function.args[0].type = ir.PointerType(ir.IntType(64))
+            builder.function.args[0].type = ir.PointerType(ir.IntType(8))
             print(builder.function.args[0])
             field_ptr = self.load_ctx_field(
                 builder, builder.function.args[0], globvar_ir
@@ -125,19 +125,18 @@ def load_ctx_field(builder, ctx_arg, offset_global):
         # Load the offset value
         offset = builder.load(offset_global)
 
-        # # Ensure ctx_arg is treated as i8* (byte pointer)
-        # # i8_type = ir.IntType(8)
-        # i8_ptr_type = ir.PointerType()
+        # Ensure ctx_arg is treated as i8* (byte pointer)
+        i8_ptr_type = ir.PointerType()
 
         # Cast ctx_arg to i8* if it isn't already
-        # if str(ctx_arg.type) != str(i8_ptr_type):
-        #     ctx_i8_ptr = builder.bitcast(ctx_arg, i8_ptr_type)
-        # else:
-        #     ctx_i8_ptr = ctx_arg
+        if str(ctx_arg.type) != str(i8_ptr_type):
+            ctx_i8_ptr = builder.bitcast(ctx_arg, i8_ptr_type)
+        else:
+            ctx_i8_ptr = ctx_arg
 
         # GEP with explicit type - this is the key fix
         field_ptr = builder.gep(
-            ctx_arg,
+            ctx_i8_ptr,
             [offset],
             inbounds=False,
         )
@@ -151,8 +150,8 @@ def load_ctx_field(builder, ctx_arg, offset_global):
                 raise KeyError
         except (KeyError, AttributeError):
             passthrough_type = ir.FunctionType(
-                ir.PointerType(),
-                [ir.IntType(32), ir.PointerType()],
+                i8_ptr_type,
+                [ir.IntType(32), i8_ptr_type],
             )
             passthrough_fn = ir.Function(
                 module,

tests/failing_tests/vmlinux/struct_field_access.py

@@ -13,10 +13,10 @@
 
 @bpf
 @section("tracepoint/syscalls/sys_enter_execve")
-def hello_world(ctx: struct_trace_event_raw_sys_enter) -> c_int32:
+def hello_world(ctx: struct_trace_event_raw_sys_enter) -> c_int64:
     b = ctx.id
     print(f"This is context field {b}")
-    return c_int32(0)
+    return c_int64(0)
 
 
 @bpf