Re: Demangling broken (was: Re: [PATCH] Demangler woes with current CVS and type names)

[Phil Edwards <phil at jaj dot com>]

On Thu, Jan 31, 2002 at 11:29:55AM +0100, Hans-Peter Nilsson wrote:
> > From: Phil Edwards <phil@jaj.com>
> > 
> > With this patch, the non-_Z names used in the testcase above can be
> > demangled by c++filt.  I've added an entry to libiberty's testsuite,
> > which fails before and passes after.
> 
> And here's another testsuite entry, for a bug exposed or
> introduced by that patch:

I'd like to think "exposed," but hey, whatever.  :-)


> It's a double doh (no pun intended, I think): For binutils, we
> just want to demangle identifiers (not types), so for that use,
> the _Z check should be there to avoid spurious demangling.
> Tracing through the demangler, I see it's just the "d" character
> demangled, so demangling replaced the whole string with a
> partial demangling.  Sorry, no obvious fix jumped up at me.

I'm about to go into a staff meeting that's scheduled to last the rest of
my natural life, but after looking at demangle_type(), my thoughts are:

Does it ever make sense for any demangling anywhere -- i.e., for non-types --
to only partially consume a mangled string?  (I wouldn't think so, but...)
Right now nothing checks for leftover characters, hence the partial
demangling.  If demangle_type() were to check for leftover characters,
and return failure in that situation, wouldn't that solve the problem
altogether, without needing additional flags?  ldmisc.c:demangle() would
then see the failure and return the "mangled" string.

Or demangle_type's parent, cplus_demangle_v3, could do the check.
That would catch extra characters left behind after non-type demangling.


Phil

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