libdrgn: allow formatting absent void objects

Object(prog, "void") is a valid object and useful as a placeholder, but trying to print one raises: TypeError: cannot format void object Allow printing "(void)<absent>" instead. Signed-off-by: Omar Sandoval <[email protected]>
osandov · Aug 29, 2024 · fb0da46 · fb0da46
1 parent ea87bfe
commit fb0da46
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 7 deletions.
diff --git a/libdrgn/language_c.c b/libdrgn/language_c.c
@@ -1530,11 +1530,6 @@ c_format_object_impl(const struct drgn_object *obj, size_t indent,
 	struct drgn_error *err;
 	struct drgn_type *underlying_type = drgn_underlying_type(obj->type);
 
-	if (drgn_type_kind(underlying_type) == DRGN_TYPE_VOID) {
-		return drgn_error_create(DRGN_ERROR_TYPE,
-					 "cannot format void object");
-	}
-
 	/*
 	 * Pointers are special because they can have an asterisk prefix if
 	 * we're dereferencing them.
@@ -1569,6 +1564,11 @@ c_format_object_impl(const struct drgn_object *obj, size_t indent,
 		return NULL;
 	}
 
+	if (drgn_type_kind(underlying_type) == DRGN_TYPE_VOID) {
+		return drgn_error_create(DRGN_ERROR_TYPE,
+					 "cannot format void object");
+	}
+
 	SWITCH_ENUM(drgn_type_kind(underlying_type),
 	case DRGN_TYPE_INT:
 	case DRGN_TYPE_BOOL:

diff --git a/tests/test_language_c.py b/tests/test_language_c.py
@@ -2223,9 +2223,8 @@ def test_function(self):
         self.assertEqual(str(obj), "(void (void))0xffff0000")
 
     def test_absent(self):
-        self.assertRaises(TypeError, str, Object(self.prog, "void"))
-
         for type_ in [
+            "void",
             "int",
             "char",
             "_Bool",