On Sun, Jan 04, 2004 at 06:56:05PM +0100, Christoph Jaeschke wrote:
> Hi,
>
> I would like to propose a offset based member name lookup of
> structs/classes. Assume:
>
> struct X {
> int a;
> int b;
> };
>
> struct Y {
> struct X x[4];
> int c;
> };
>
> struct Z {
> Y y;
> };
>
> If you apply a patch for gdb 6.0 I've prepared, you can ask gdb by
>
> ptype Z + 28
>
> about Z's relative name at offset 28
>
> .y.x[3].b
>
> using
>
> ptype Z+28, typechain
>
> gdb will append also the typechain
>
> .y.x[3].b, typechain = ::Y::X[4]::int
>
>
> There may be a better suited command than 'ptype' for it, it was choosen
> just because it was the simplest way to add it.
>
> The patch contains also a caching mechanism, speeding up a lot if you do
> many lookups in big nested structures. It has a minimal memory
> requirement and will not hurt for single lookups.
>
> The patch can be send if you are interested in.
Well, I don't like the syntax, but I think this is a wonderful idea.
The other feature I've been meaning to add since forever is a variant
of ptype which shows byte offsets for every field.
The problem with using ptype is that "Z+28" already has a meaning; gdb
will try to add the two, or call an overloaded + operator in C++, et
cetera. This should probably be a new command; that'll be more useful
for MI anyway.