re PR c++/20232 (ICE with covariancy)

cp:
	PR c++/20232
	* class.c (update_vtable_entry_for_fn): Don't crash on invalid
	covariancy.

	* cp-tree.g (THUNK_TARGET): Expand comment.
	* method.c (use_thunk): Make sure we also use the target, if that
	is a thunk.
testsuite:
	PR c++/20232
	* g++.dg/inherit/covariant12.C: New.

From-SVN: r95733

gcc/cp/ChangeLog

+2005-03-01  Nathan Sidwell  <nathan@codesourcery.com>
+
+	PR c++/20232
+	* class.c (update_vtable_entry_for_fn): Don't crash on invalid
+	covariancy. 
+
+	* cp-tree.g (THUNK_TARGET): Expand comment.
+	* method.c (use_thunk): Make sure we also use the target, if that
+	is a thunk.
+
 2005-02-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/20206

gcc/cp/class.c

@@ -2048,14 +2048,17 @@ update_vtable_entry_for_fn (tree t, tree binfo, tree fn, tree* virtuals,
 	  tree thunk_binfo, base_binfo;
 
 	  /* Find the base binfo within the overriding function's
-	     return type.  */
+	     return type.  We will always find a thunk_binfo, except
+	     when the covariancy is invalid (which we will have
+	     already diagnosed).  */
 	  for (base_binfo = TYPE_BINFO (base_return),
 	       thunk_binfo = TYPE_BINFO (over_return);
-	       !SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
-				   BINFO_TYPE (base_binfo));
+	       thunk_binfo;
 	       thunk_binfo = TREE_CHAIN (thunk_binfo))
-	    continue;
-
+	    if (SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
+				   BINFO_TYPE (base_binfo)))
+	      break;
+	  
 	  /* See if virtual inheritance is involved.  */
 	  for (virtual_offset = thunk_binfo;
 	       virtual_offset;
@@ -2063,7 +2066,8 @@ update_vtable_entry_for_fn (tree t, tree binfo, tree fn, tree* virtuals,
 	    if (BINFO_VIRTUAL_P (virtual_offset))
 	      break;
 	  
-	  if (virtual_offset || !BINFO_OFFSET_ZEROP (thunk_binfo))
+	  if (virtual_offset
+	      || (thunk_binfo && !BINFO_OFFSET_ZEROP (thunk_binfo)))
 	    {
 	      tree offset = convert (ssizetype, BINFO_OFFSET (thunk_binfo));
 

gcc/cp/cp-tree.h

@@ -2913,7 +2913,8 @@ struct lang_decl GTY(())
 #define THUNK_ALIAS(DECL) \
   (DECL_LANG_SPECIFIC (FUNCTION_DECL_CHECK (DECL))->decl_flags.u.template_info)
 
-/* For thunk NODE, this is the FUNCTION_DECL thunked to.  */
+/* For thunk NODE, this is the FUNCTION_DECL thunked to.  It is
+   possible for the target to be a thunk too.  */
 #define THUNK_TARGET(NODE)				\
   (DECL_LANG_SPECIFIC (NODE)->u.f.befriending_classes)
 

gcc/cp/method.c

@@ -328,6 +328,10 @@ use_thunk (tree thunk_fndecl, bool emit_p)
        There's no need to process this thunk again.  */
     return;
 
+  if (DECL_THUNK_P (function))
+    /* The target is itself a thunk, process it now.  */
+    use_thunk (function, emit_p);
+  
   /* Thunks are always addressable; they only appear in vtables.  */
   TREE_ADDRESSABLE (thunk_fndecl) = 1;
 

gcc/testsuite/ChangeLog

+2005-03-01  Nathan Sidwell  <nathan@codesourcery.com>
+
+	PR c++/20232
+	* g++.dg/inherit/covariant12.C: New.
+
 2005-02-28  Tobias Schl"uter  <tobias.schlueter@physik.uni-muenchen.de>
 
 	PR fortran/19479

gcc/testsuite/g++.dg/inherit/covariant12.C

+// Copyright (C) 2004 Free Software Foundation, Inc.
+// Contributed by Nathan Sidwell 27 Feb 2005<nathan@codesourcery.com>
+
+// PR 20232: ICE on invalid
+
+struct T { };
+
+struct S;
+
+struct B
+{
+  virtual T *Foo (); // { dg-error "overriding" "" }
+};
+
+struct D : B
+{
+  virtual S *Foo (); // { dg-error "invalid covariant" "" }
+};