Fix https://bugzilla.redhat.com/show_bug.cgi?id=849357

	* cp-valprint.c (cp_print_value_fields): Use get_vptr_fieldno.
gdb/testsuite
	* gdb.cp/derivation.exp: Add regression test.
	* gdb.cp/derivation.cc (class V_base, class V_inter, class
	V_derived): New.
	(vderived): New global.

3 files changed, 44 insertions, 0 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 6707751..a68f69d 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2012-09-27  Tom Tromey  <tromey@redhat.com>
+
+	* gdb.cp/derivation.exp: Add regression test.
+	* gdb.cp/derivation.cc (class V_base, class V_inter, class
+	V_derived): New.
+	(vderived): New global.
+
 2012-09-26  Tom Tromey  <tromey@redhat.com>
 
 	* gdb.dwarf2/dw2-common-block.S: New file.
diff --git a/gdb/testsuite/gdb.cp/derivation.cc b/gdb/testsuite/gdb.cp/derivation.cc
index 942fcd2..fcd57ce 100644
--- a/gdb/testsuite/gdb.cp/derivation.cc
+++ b/gdb/testsuite/gdb.cp/derivation.cc
@@ -118,8 +118,37 @@ public:
     
 };
 
+class V_base
+{
+public:
+  virtual void m();
+  int base;
+};
+
+void
+V_base::m()
+{
+}
+
+class V_inter : public virtual V_base
+{
+public:
+  virtual void f();
+  int inter;
+};
+
+void
+V_inter::f()
+{
+}
 
+class V_derived : public V_inter
+{
+public:
+  double x;
+};
 
+V_derived vderived;
 
 int A::afoo() {
     return 1;
diff --git a/gdb/testsuite/gdb.cp/derivation.exp b/gdb/testsuite/gdb.cp/derivation.exp
index b752b52..a4210d9 100644
--- a/gdb/testsuite/gdb.cp/derivation.exp
+++ b/gdb/testsuite/gdb.cp/derivation.exp
@@ -176,3 +176,11 @@ gdb_test_multiple "frame" "re-selected 'main' frame after inferior call" {
 
 gdb_test "print g_instance.bfoo()" "\\$\[0-9\]+ = 2" "print value of g_instance.bfoo()"
 gdb_test "print g_instance.cfoo()" "\\$\[0-9\]+ = 3" "print value of g_instance.cfoo()"
+
+# This is a regression test for a bug that caused a crash when trying
+# to print the vtbl pointer.  We don't care about the output so much
+# here (it is tested elsewhere), just that gdb doesn't crash.  We test
+# "ptype" first because, before the gdb fix, that was the only code
+# path calling get_vptr_fieldno.
+gdb_test "ptype vderived" "type = .*"
+gdb_test "print vderived" " = {.* inter = 0.*x = 0}"