Re: macro-expanding expressions in GDB

[Stan Shebs <shebs at apple dot com>]

Jim Blandy wrote:
> 
> Daniel Berlin <dan@cgsoftware.com> writes:
> > Speaking of real parsers, i've hooked up GCC's cpplib to GDB's c
> > expression parser if anyone is interested in the work.  I'll
> > eventually submit it once the hooks to do the necessary gdb lookups to
> > handle macros are done.  Neil said he'd try to have something
> 
> This is a feature to die for.  Fantastic.

Amen.  If I didn't have so many Apple-specific *&^%#$@! patches to
deal with, I'd want to be having fun with this.

> I have two concerns about using cpplib:
> - I don't want GDB builds to require the GCC sources around.  This is
>   mostly bureacracy --- we'd need to have cpplib moved into its own
>   top-level directory, so we could share it with GCC.

Presumably it can be handled similarly to libiberty, with two
copies, and on-demand resyncing.  Since GDB only needs the subset
functionality, it can probably be a little behind without causing
any problems.

> - I wonder how much of cpplib we actually need.  We don't need
>   #includes, #ifs, or CPP expression evaluation.  cpplib seems
>   heavyweight.  This is somewhat nitpicky.

It's true that cppmacro.c is only about 10% of the cpplib sources,
but in practice it seems like a lot of trouble to further partition
cpplib.  GDB doesn't use all of BFD either, but who wants to go to
the trouble of partitioning it into a reading-only part?

> Sorry, which Niel?

That's Neil Booth.

Stan