Re: [RFA] c++/11734

[Keith Seitz <keiths@redhat.com>]

On 06/23/2010 07:25 PM, Doug Evans wrote:
> I think the change to linespec.c should be a separate patch.

I shall try to isolate the linespec.c change and a test.

> And I think decode_compound shouldn't be modifying what saved_arg
> points to.

Ah, that's right. Gdb passes these things around like they were going 
out of style... That is easy enough to avoid, though.

I guess this raises the follow-on question, does something like 
"'c::foo()' const" work? I suspect not (with or without my patch). I 
will write some new tests for this and see what I can do.

> So it seems like a better way to go is to
> teach locate_first_half about all quote characters.

I'll investigate that avenue, which is, I gather, to treat all single 
and double quotes "equivalently." [i.e, probably not exactly 
identically: "XXX" == 'XXX'; "XXX' and 'XXX" illegal; not even going to 
try "X'Y'Z" -- I'd be better off rewriting linespec.c than tackle some 
of these problems!]

> There may be more
> going on here though, I don't understand why decode_line_1 has *both*
> is_quoted and is_quote_enclosed (is there some cleanup that can be
> done here, or is there a technical reason to handle " different from
> '?).

At one time, I convinced myself that I understood the difference between 
is_quoted and is_quote_enclosed... I'll have to spend some time to 
remind/convince myself again.

> For the lookup_partial_symbol patch:
 >
> In the case of simple_name != NULL, do we need to call
> SYMBOL_MATCHES_SEARCH_NAME twice?
> IWBN if psymtabs didn't require that complexity and *only* recorded
> the un-overloaded name.

If I understand your argument correctly, yes, it seems that if we know 
that SYMBOL_MATCHES_SEARCH_NAME uses strcmp_iw, then we do not need to 
call it twice, since strcmp_iw ("foo", "foo()") will not match. But this 
seems just as hacky as relying on a subsequent symtab search to find the 
right symbol. What happens if SYMBOL_MATCHES_SEARCH_NAME is changed to 
use something other than strcmp_iw. [I know that is highly improbable in 
the near future.]

> Could we set name to simple_name when simple_name is created, and then
> have only one call to SYMBOL_MATCHES_SEARCH_NAME?

I've reversed the logic in this (check simple name first), 
short-circuiting the second call (again, since we know that it can never 
match because SYMBOL_MATCHES_SEARCH_NAME boils down to strcmp_iw, for 
which the second argument cannot contain parenthesis unless the first 
argument does). This currently shows no regressions, either.

> However psymtabs are searched *after* symtabs.

That's right. psymtabs are searched later:

> This patch works because it turns out that we will later do a search in the
> full symtab, but that's more by accident than design:

Yup. That was what I meant by "hacky."

> This situation is not well solved by our normal psymtabs->symtabs lazy
> expansion design.
> I don't have a specific proposal for a better fix at the moment.

I don't either, but I'm going to try to address your concerns and your 
other suggestion to immediately search for the symbol in the symtab.

Thank you for reviewing this.
Keith