cpplib.c (do_ifdef, do_ifndef): Don't segfault if parse_ifdef returned NULL.

2000-06-06  Jakub Jelinek  <jakub@redhat.com>

	* cpplib.c (do_ifdef, do_ifndef): Don't segfault if parse_ifdef
	returned NULL.

From-SVN: r34448

gcc/ChangeLog

+2000-06-06  Jakub Jelinek  <jakub@redhat.com>
+
+	* cpplib.c (do_ifdef, do_ifndef): Don't segfault if parse_ifdef
+	returned NULL.
+
 Wed Jun  7 20:34:33 2000  Denis Chertykov  <denisc@overta.ru>
 
 	* config/avr/avr.c (asm_output_section_name): output section

gcc/cpplib.c

@@ -1126,10 +1126,13 @@ do_ifdef (pfile)
 {
   int def = 0;
   const cpp_hashnode *node = parse_ifdef (pfile, dtable[T_IFDEF].name);
-  if (node->type == T_POISON)
-    cpp_error (pfile, "attempt to use poisoned `%s'", node->name);
-  else
-    def = (node->type != T_VOID);
+  if (node)
+    {
+      if (node->type == T_POISON)
+	cpp_error (pfile, "attempt to use poisoned `%s'", node->name);
+      else
+	def = (node->type != T_VOID);
+    }
   push_conditional (pfile, !def, T_IFDEF, 0);
   return 0;
 }
@@ -1147,11 +1150,13 @@ do_ifndef (pfile)
 
   start_of_file = pfile->only_seen_white == 2;
   cmacro = parse_ifdef (pfile, dtable[T_IFNDEF].name);
-  if (cmacro->type == T_POISON)
-    cpp_error (pfile, "attempt to use poisoned `%s'", cmacro->name);
-  else
-    def = (cmacro->type != T_VOID);
-
+  if (cmacro)
+    {
+      if (cmacro->type == T_POISON)
+	cpp_error (pfile, "attempt to use poisoned `%s'", cmacro->name);
+      else
+	def = (cmacro->type != T_VOID);
+    }
   push_conditional (pfile, def, T_IFNDEF,
 		    start_of_file ? cmacro : 0);
   return 0;

gcc/testsuite/gcc.dg/cpp-if5.c

+/* Regression test: #ifdef 0 should not crash.  Problem noted by
+   Jakub Jelinek <jakub@redhat.com>.  */
+/* { dg-do preprocess } */
+
+#ifdef 0  /* { dg-error "with invalid argument" } */
+#error not seen
+#endif
+
+#ifndef 0  /* { dg-error "with invalid argument" } */
+#else
+#error not seen
+#endif