c++/10893: wrong class mapping for empty bases

[yanliu@ca.ibm.com]

>Number:         10893
>Category:       c++
>Synopsis:       wrong class mapping for empty bases
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Wed May 21 02:36:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Yan Liu
>Release:        unknown-1.0
>Organization:
>Environment:
linuxppc system, version 3.2 32bit mode.
>Description:

>How-To-Repeat:
using -fdump-class-hierarchy option to get the class layout of the above testcase. You will find the empty base class  E1 and E are at offset 4 in struct D1 class layout. There is  a another data member also be mapped at the same address, which is wrong according to C++ ABI. 
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="kaka.C"
Content-Disposition: inline; filename="kaka.C"

struct E {};
struct E1: public E {};
struct E2: public E {};
struct D: public virtual E1, public E2 {
};
struct D1: public D {
	int d1;
};
D1 objd1;