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Problem with virtual function pointers
- From: Corinna Vinschen <vinschen at redhat dot com>
- To: gdb at sources dot redhat dot com
- Date: Thu, 27 Mar 2003 15:24:12 +0100
- Subject: Problem with virtual function pointers
- Reply-to: gdb at sources dot redhat dot com
Hi,
I'm just investigating a problem which XStormy16 gets in
gdb.c++/printmethod.exp:
print theA->virt^M
$1 = invalid pointer to member function^M
FAIL: gdb.c++/printmethod.exp: print virtual method.
It turned out that the error happens in xstormy16_pointer_to_address().
This function converts an address to a jump table entry into a pointer
to the actual function. To do this, it calls a conversion routine,
which is only called if the following condition applies:
enum type_code target = TYPE_CODE (TYPE_TARGET_TYPE (type));
if (target == TYPE_CODE_FUNC || target == TYPE_CODE_METHOD)
convert();
Surprisingly (at least for me) this fails for the above case. Looking
into type, I found that type is TYPE_CODE_PTR which is correct, but
target_type is TYPE_CODE_VOID! Sure, the above virtual method is of
type void but is that really ok? Shouldn't that be
type: TYPE_CODE_PTR
type->target_type: TYPE_CODE_METHOD
type->target_type->target_type: TYPE_CODE_VOID
?
Does somebody know why that happens? Is that just a bug in gdb? Or
could that be related to incorrect debug info from gcc?
Corinna
--
Corinna Vinschen
Cygwin Developer
Red Hat, Inc.
mailto:vinschen at redhat dot com