Do not make assumptions about type va_list.

Author: fangerer

graalpython/com.oracle.graal.python.cext/src/capi.h

@@ -352,13 +352,14 @@ int bufferdecorator_getbuffer(PyBufferDecorator *self, Py_buffer *view, int flag
  * together, the managed array with arguments will be escape analyzed away.
  */
 #define CallWithPolyglotArgs(result, last, off, function, ...)          \
+    va_list __va_list;                                                  \
     int __poly_argc = polyglot_get_arg_count();                         \
     int __poly_args_s = sizeof(void*) * (__poly_argc - off);            \
     void **__poly_args = truffle_managed_malloc(__poly_args_s);         \
     for (int i = off; i < __poly_argc; i++) {                           \
         __poly_args[i - off] = polyglot_get_arg(i);                     \
     }                                                                   \
-    result = function(__VA_ARGS__, NULL, __poly_args, 0)
+    result = function(__VA_ARGS__, __va_list, __poly_args, 0)
 #else
 /*
  * (tfel): Just skip the optimization with using a managed malloc and use

graalpython/com.oracle.graal.python.cext/src/unicodeobject.c

@@ -120,6 +120,7 @@ MUST_INLINE PyObject* PyTruffle_Unicode_FromFormat(const char *fmt, va_list va,
     char* fmtcpy = (char*) malloc(fmt_size*sizeof(char));
     memcpy(fmtcpy, fmt, fmt_size);
     char* c = fmtcpy;
+    int use_valist = args == NULL;
 
     int remaining_space = 2047;
     char* buffer = (char*)calloc(sizeof(char), remaining_space + 1);
@@ -140,7 +141,7 @@ MUST_INLINE PyObject* PyTruffle_Unicode_FromFormat(const char *fmt, va_list va,
                     allocated = NULL;
                 }
                 variable = NULL;
-            } else if (va != NULL) {
+            } else if (use_valist) {
                 bytes_written = vsnprintf(buffer, remaining_space, fmtcpy, va);
             } else {
                 strncpy(buffer, fmtcpy, remaining_space);
@@ -165,7 +166,7 @@ MUST_INLINE PyObject* PyTruffle_Unicode_FromFormat(const char *fmt, va_list va,
             case 'R':
                 if (converter == NULL) converter = PyObject_Repr;
                 c[1] = 's';
-                allocated = variable = as_char_pointer(converter(args == NULL ? va_arg(va, PyObject*) : (PyObject*)(args[argc++])));
+                allocated = variable = as_char_pointer(converter(use_valist ? va_arg(va, PyObject*) : (PyObject*)(args[argc++])));
                 break;
             case '%':
                 // literal %
@@ -192,7 +193,7 @@ MUST_INLINE PyObject* PyTruffle_Unicode_FromFormat(const char *fmt, va_list va,
         if (allocated) {
             free(allocated);
         }
-    } else if (va != NULL) {
+    } else if (use_valist) {
         vsnprintf(buffer, remaining_space, fmtcpy, va);
     } else {
         strncpy(buffer, fmtcpy, remaining_space);