Re: [RFA] Select a particular mangling of a demangled symbol in lookup_block_symbol

Elena Zannoni
2002-03-19T22:47:29Z

Elena Zannoni writes:
> Daniel Jacobowitz writes:
> > I just described the problem this patch addresses in my testsuite patch;
> > perhaps not the best place :) Here's the relevant bit:
> >
> > - Multiple symbols with the same demangled name. We can work around this
> > for stabs, because we have the physname. We don't have that option for
> > DWARF-2, and we shouldn't need to for stabs. I have a patch for the
> > workaround. We get the [not-in-charge] constructor by default,
> > unfortunately.
> >
> >
> > What this means is that we call lookup_block_symbol on something like:
> > _ZN3fooC1ERS_
> > but get the information for:
> > _ZN3fooC2ERS_
> >
> > The breakpoint ends up on the base-not-in-charge constructor.
> >
> > What we really SHOULD do is set it on both constructors silently, without
> > even acknowledging that they are different functions, or else offer the user
> > the choice. My preference is actually for the former. That requires
> > support for a single function existing in multiple places, which will also
> > give us nice things like better support for inlined functions with DWARF-2
> > (which will always be somewhat shoddy due to the nature of inlining, in that
> > it only occurs with lots of other optimization - but we can do much better
> > than we do).
> >
> > Is this patch OK, or is it deemed too gross?
> >
> > --
> > Daniel Jacobowitz Carnegie Mellon University
> > MontaVista Software Debian GNU/Linux Developer
> >
> > 2002-02-14 Daniel Jacobowitz <drow@mvista.com>
> >
> > * symtab.h (lookup_block_symbol): Add mangled_name argument
> > to prototype.
> >
> > * symmisc.c (maintenance_check_symtabs): Call lookup_block_symbol
> > with new mangled_name argument.
> > * linespec.c (decode_line_1): Likewise.
> > * valops (value_of_this): Likewise.
> > * symtab.c (lookup_transparent_type): Likewise.
> > (lookup_symbol_aux): Likewise. Accept new mangled_name argument.
> > (lookup_symbol): If we are given a mangled name, pass it down
> > to lookup_symbol_aux.
> > (lookup_block_symbol): If we are given a mangled name to check
> > against, only return symbols which match it.
> >
> > @@ -567,6 +568,7 @@ lookup_symbol (const char *name, const s
> > {
> > char *modified_name = NULL;
> > char *modified_name2 = NULL;
> > + const char *mangled_name = NULL;
> > int needtofreename = 0;
> > struct symbol *returnval;
> >
> > @@ -592,13 +594,14 @@ lookup_symbol (const char *name, const s
> > modified_name2 = cplus_demangle (modified_name, DMGL_ANSI | DMGL_PARAMS);
> > if (modified_name2)
> > {
> > + mangled_name = name;
> > modified_name = modified_name2;
> > needtofreename = 1;
> > }
> > }
> >
> > - returnval = lookup_symbol_aux (modified_name, block, namespace,
> > - is_a_field_of_this, symtab);
> > + returnval = lookup_symbol_aux (modified_name, mangled_name, block,
> > + namespace, is_a_field_of_this, symtab);
> > if (needtofreename)
> > xfree (modified_name2);
> >
>
>
> OK, approved. But I have my usual couple of questions:
>
> Was the corresponding testsuite patch sorted out? Looks like it
> wasn't. Does this patch have any effect on the testsuite results w/o
> the testsuite patch?
>
> In the above, should it be mangled_name = name or mangled_name =
> modified_name? It would seem more uniform with the rest of the
> function if we just used modified_name. Unless there is some problem
> with case sensitivity, in which case, calling cplus_demangle with
> modified_name seems wrong anyway. I.e. is it guaranteed that
> case_sensitive_off is NOT in effect? Just out of curiosity What
> would happen if the user sets the case sensitivity off?
> Wouldn't it change _ZN3fooC1ERS_ to _zn3fooc1ers_ ? (of course the user
> can always do a lot of things to screw himself up)
>
> I guess what I am really asking is when is lookup_symbol called with a
> mangled name. I tried to do "break foo::foo", and I never saw it called
> with a mangled name.
>
> Elena
>
>

Replying to myself. I was testing with dwarf2, but using stabs I can
see it. I can also see that we call cplus_demangle (__3foor3foo, ...)
instead of cplus_demangle (__3fooR3foo, ...), if 'set case off'. But
it returns foo::foo(long double, foo) anyway. So it works?

Elena