macro-expanding expressions in GDB

[Jim Blandy <jimb@zwingli.cygnus.com>]

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.

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.
- 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.

Sorry, which Niel?  If I can find the bandwidth, I'd love to do the
symbol table support for this.

> I also submitted patches to gcc to make it produce the dwarf2 macro
> info necessary for us to let the user use macros from GDB that are
> used in the source.

And we don't even need to wait for that.  We can add the macro info to
the .s files manually, and test against those files.