From: Jakub Jelinek <jakub@redhat.com>
Date: Mon, 25 Jun 2018 17:39:55 +0000 (+0200)
Subject: backport: re PR c++/85068 (ICE with invalid covariant return type hierarchy)
X-Git-Tag: releases/gcc-6.5.0~198
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2a775eeb61c4fcee6859087625d0277fadc3baa9;p=thirdparty%2Fgcc.git

backport: re PR c++/85068 (ICE with invalid covariant return type hierarchy)

	Backported from mainline
	2018-03-27  Jakub Jelinek  <jakub@redhat.com>

	PR c++/85068
	* class.c (update_vtable_entry_for_fn): Don't ICE if base_binfo
	is NULL.  Assert if thunk_binfo is NULL then errorcount is non-zero.

	* g++.dg/inherit/covariant22.C: New test.

From-SVN: r262086
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index c831f14f09c4..92171f91b911 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,6 +1,12 @@
 2018-06-25  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2018-03-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/85068
+	* class.c (update_vtable_entry_for_fn): Don't ICE if base_binfo
+	is NULL.  Assert if thunk_binfo is NULL then errorcount is non-zero.
+
 	2018-03-16  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/84874
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 86e7e003fe49..6de0421d6dc6 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -2669,19 +2669,20 @@ update_vtable_entry_for_fn (tree t, tree binfo, tree fn, tree* virtuals,
 	     order.  Of course it is lame that we have to repeat the
 	     search here anyway -- we should really be caching pieces
 	     of the vtable and avoiding this repeated work.  */
-	  tree thunk_binfo, base_binfo;
+	  tree thunk_binfo = NULL_TREE;
+	  tree base_binfo = TYPE_BINFO (base_return);
 
 	  /* Find the base binfo within the overriding function's
 	     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);
-	       thunk_binfo;
-	       thunk_binfo = TREE_CHAIN (thunk_binfo))
-	    if (SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
-				   BINFO_TYPE (base_binfo)))
-	      break;
+	  if (base_binfo)
+	    for (thunk_binfo = TYPE_BINFO (over_return); thunk_binfo;
+		 thunk_binfo = TREE_CHAIN (thunk_binfo))
+	      if (SAME_BINFO_TYPE_P (BINFO_TYPE (thunk_binfo),
+				     BINFO_TYPE (base_binfo)))
+		break;
+	  gcc_assert (thunk_binfo || errorcount);
 
 	  /* See if virtual inheritance is involved.  */
 	  for (virtual_offset = thunk_binfo;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8fcb4c316c9e..3eef4e304fb5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2018-06-25  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2018-03-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/85068
+	* g++.dg/inherit/covariant22.C: New test.
+
 	2018-03-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR inline-asm/85034
diff --git a/gcc/testsuite/g++.dg/inherit/covariant22.C b/gcc/testsuite/g++.dg/inherit/covariant22.C
new file mode 100644
index 000000000000..26c96e6abfc6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/inherit/covariant22.C
@@ -0,0 +1,19 @@
+// PR c++/85068
+// { dg-do compile }
+
+struct A;
+
+struct B
+{
+  virtual A *foo ();	// { dg-error "overriding" }
+};
+
+struct C : virtual B
+{
+  virtual C *foo ();	// { dg-error "invalid covariant return type for" }
+};
+
+struct D : C
+{
+  virtual C *foo ();
+};