[Bug target/34982] [4.3 regression] calling a function with undefined parameters causes segmentation fault at -O1 or higher

["hubicka at ucw dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #6 from hubicka at ucw dot cz  2008-01-27 13:54 -------
Subject: Re:  [4.3 regression] calling a function with undefined parameters
causes segmentation fault at -O1 or higher

cgraph_local_info still behaves as expected returning NULL when info is
not computed yet. Unfortunately check to simply ignore it when not
available has been added to ix86_function_regparm that makes this bug
lead to wrong code. (revision 123146)

There are two occurences where we can ix86_function_regparm. First one
is for compatibility checking, I would just declare it invalid - we
don't want the type comatiblity to depend on backend decision and I
think it is perfectly sane to reject any types specifying different
REGPARM values or where one specify and other doesn't.

I am testing attached patch and will commit it if passes.

Other case is from gimplifier, I am looking into it.  This definitly has
to go or we need to drop the feature :(

Honza

Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c  (revision 131882)
+++ config/i386/i386.c  (working copy)
@@ -3148,6 +3148,7 @@ ix86_comp_type_attributes (const_tree ty
 {
   /* Check for mismatch of non-default calling convention.  */
   const char *const rtdstr = TARGET_RTD ? "cdecl" : "stdcall";
+  tree attr1, attr2;

   if (TREE_CODE (type1) != FUNCTION_TYPE
       && TREE_CODE (type1) != METHOD_TYPE)
@@ -3155,11 +3156,27 @@ ix86_comp_type_attributes (const_tree ty

   /* Check for mismatched fastcall/regparm types.  */
   if ((!lookup_attribute ("fastcall", TYPE_ATTRIBUTES (type1))
-       != !lookup_attribute ("fastcall", TYPE_ATTRIBUTES (type2)))
-      || (ix86_function_regparm (type1, NULL)
-         != ix86_function_regparm (type2, NULL)))
+       != !lookup_attribute ("fastcall", TYPE_ATTRIBUTES (type2))))
     return 0;

+  /* We don't want to use ix86_function_regparm here: it's decision depends
+     on middle end information, like localness of functions.  Here we only
want
+     to know if types are declared compatible.  */
+  attr1 = lookup_attribute ("regparm", TYPE_ATTRIBUTES (type1));
+  attr2 = lookup_attribute ("regparm", TYPE_ATTRIBUTES (type2));
+
+  if ((attr1 != NULL_TREE) != (attr2 != NULL_TREE))
+    return 0;
+
+  if (attr1)
+    {
+      int val1 = TREE_INT_CST_LOW (TREE_VALUE (TREE_VALUE (attr1)));
+      int val2 = TREE_INT_CST_LOW (TREE_VALUE (TREE_VALUE (attr2)));
+
+      if (val1 != val2)
+       return 0;
+    }
+
   /* Check for mismatched sseregparm types.  */
   if (!lookup_attribute ("sseregparm", TYPE_ATTRIBUTES (type1))
       != !lookup_attribute ("sseregparm", TYPE_ATTRIBUTES (type2)))


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34982