re PR c/17301 (ICE on wrong usage of __builtin_stdarg_start)

	PR c/17301
	* builtins.c (expand_builtin_va_start): Check for too few
	arguments to va_start.

testsuite:
	* gcc.dg/pr17301-1.c: New test.

From-SVN: r88835

gcc/ChangeLog

 2004-10-10  Joseph S. Myers  <jsm@polyomino.org.uk>
 
+	PR c/17301
+	* builtins.c (expand_builtin_va_start): Check for too few
+	arguments to va_start.
+
+2004-10-10  Joseph S. Myers  <jsm@polyomino.org.uk>
+
 	PR c/17189
 	* c-decl.c (grokfield): Make diagnostic for bad cases of unnamed
 	fields a pedwarn.  Pedwarn here for unnamed structs/unions if

gcc/builtins.c

@@ -3861,6 +3861,11 @@ expand_builtin_va_start (tree arglist)
 
   chain = TREE_CHAIN (arglist);
 
+  if (!chain)
+    {
+      error ("too few arguments to function %<va_start%>");
+      return const0_rtx;
+    }
   if (TREE_CHAIN (chain))
     error ("too many arguments to function %<va_start%>");
 

gcc/testsuite/ChangeLog

 2004-10-10  Joseph S. Myers  <jsm@polyomino.org.uk>
 
+	PR c/17301
+	* gcc.dg/pr17301-1.c: New test.
+
+2004-10-10  Joseph S. Myers  <jsm@polyomino.org.uk>
+
 	PR c/17189
 	* gcc.dg/anon-struct-5.c: New test.
 

gcc/testsuite/gcc.dg/pr17301-1.c

+/* Invalid use of __builtin_stdarg_start should not cause an ICE.  Bug
+   17301.  */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int
+write_format (char *format, ...)
+{
+  __builtin_va_list p;
+  __builtin_stdarg_start (p); /* { dg-error "error: too few arguments to function 'va_start'" } */
+}