[PATCH 12/18] -Wwrite-strings: More fix-old-Python-API wrappers

Pedro Alves
2017-04-04T17:33:10Z

When building against Python 2.7, -Wwrite-strings flags several cases
of passing a string literal to Python functions that expect a "char
*". This commit addresses the issue like we already handle several
other similar cases -- wrap the Python API with our own fixed
version that adds the necessary constification.

gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>

* python/python-internal.h (gdb_PyObject_CallMethod)
(gdb_PyErr_NewException, gdb_PySys_GetObject, gdb_PySys_SetPath):
New functions.
(GDB_PYSYS_SETPATH_CHAR, PyObject_CallMethod, PyErr_NewException)
(PySys_GetObject, PySys_SetPath): New macros.
---
gdb/python/python-internal.h | 63 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)

diff --git a/gdb/python/python-internal.h b/gdb/python/python-internal.h
index 4dd413d..55efd75 100644
--- a/gdb/python/python-internal.h
+++ b/gdb/python/python-internal.h
@@ -223,6 +223,69 @@ gdb_PyObject_HasAttrString (PyObject *obj,

#define PyObject_HasAttrString(obj, attr) gdb_PyObject_HasAttrString (obj, attr)

+/* PyObject_CallMethod's 'method' and 'format' parameters were missing
+ the 'const' qualifier before Python 3.4. Hence, we wrap the
+ function in our own version to avoid errors with string literals.
+ Note, this is a variadic template because PyObject_CallMethod is a
+ varargs function and Python doesn't have a "PyObject_VaCallMethod"
+ variant taking a va_list that we could defer to instead. */
+
+template<typename... Args>
+static inline PyObject *
+gdb_PyObject_CallMethod (PyObject *o, const char *method, const char *format,
+ Args... args) /* ARI: editCase function */
+{
+ return PyObject_CallMethod (o,
+ const_cast<char *> (method),
+ const_cast<char *> (format),
+ args...);
+}
+
+#undef PyObject_CallMethod
+#define PyObject_CallMethod gdb_PyObject_CallMethod
+
+/* The 'name' parameter of PyErr_NewException was missing the 'const'
+ qualifier in Python <= 3.4. Hence, we wrap it in a function to
+ avoid errors when compiled with -Werror. */
+
+static inline PyObject*
+gdb_PyErr_NewException (const char *name, PyObject *base, PyObject *dict)
+{
+ return PyErr_NewException (const_cast<char *> (name), base, dict);
+}
+
+#define PyErr_NewException gdb_PyErr_NewException
+
+/* PySys_GetObject's 'name' parameter was missing the 'const'
+ qualifier before Python 3.4. Hence, we wrap it in a function to
+ avoid errors when compiled with -Werror. */
+
+static inline PyObject *
+gdb_PySys_GetObject (const char *name)
+{
+ return PySys_GetObject (const_cast<char *> (name));
+}
+
+#define PySys_GetObject gdb_PySys_GetObject
+
+/* PySys_SetPath's 'path' parameter was missing the 'const' qualifier
+ before Python 3.6. Hence, we wrap it in a function to avoid errors
+ when compiled with -Werror. */
+
+#ifdef IS_PY3K
+# define GDB_PYSYS_SETPATH_CHAR wchar_t
+#else
+# define GDB_PYSYS_SETPATH_CHAR char
+#endif
+
+static inline void
+gdb_PySys_SetPath (const GDB_PYSYS_SETPATH_CHAR *path)
+{
+ PySys_SetPath (const_cast<GDB_PYSYS_SETPATH_CHAR *> (path));
+}
+
+#define PySys_SetPath gdb_PySys_SetPath
+
/* In order to be able to parse symtab_and_line_to_sal_object function
a real symtab_and_line structure is needed. */
#include "symtab.h"
--
2.5.5