[Converted from Gnats 2384]

The appended exampled illustrates a problem in gdb's handling of baseclasses in shared libraries. When gdb resolves type information for class "derived" from objfile base-in-so.x, it fills in the TYPE_VPTR_BASETYPE field with class "base" from objfile base-in-so-base.so.  When the program is rerun the type information for base-in-so-base.so is discarded leaving TYPE_VPTR_BASETYPE dangling.

Release:
6.7.1

Environment:
i386-linux

How-To-Repeat:
g++ -g -shared base-in-so-base.cc -o base-in-so-base.so
g++ -g base-in-so.cc -o base-in-so.x -Wl,-rpath,`pwd` base-in-so-base.so

gdb base-in-so.x
break base-in-so.cc:20
run
[hits breakpoint]
print d.meth()
$1 = 42
run
Start at beginning? y
[hits breakpoint]
print d.meth()
--> segv

If the program doesn't hit a segv, it may just be that gdb got lucky.  Putting in an assert will show the issue too:

--- gdbtypes.c~ 2007-12-13 15:20:59.062220000 -0800
+++ gdbtypes.c  2007-12-13 15:21:39.408302000 -0800
@@ -1307,6 +1307,7 @@ fill_in_vptr_fieldno (struct type *type)
          fill_in_vptr_fieldno (baseclass);
          if (TYPE_VPTR_FIELDNO (baseclass) >= 0)
            {
+             gdb_assert (TYPE_OBJFILE (type) == TYPE_OBJFILE (baseclass));
              TYPE_VPTR_FIELDNO (type) = TYPE_VPTR_FIELDNO (baseclass);
              TYPE_VPTR_BASETYPE (type) = TYPE_VPTR_BASETYPE (baseclass);
              break;