RE: Problem calling functions within gdb (version 7.5)

[Saurabh T <saurabh@hotmail.com>]

----------------------------------------
> Date: Thu, 25 Apr 2013 08:09:31 -0700
> From: keiths@redhat.com
> To: saurabh@hotmail.com
> CC: gdb@sourceware.org
> Subject: Re: Problem calling functions within gdb (version 7.5)
>
> On 04/25/2013 07:24 AM, Saurabh T wrote:
> >> From: tromey@redhat.com
> >>
> >> Saurabh> 1. call fn(3, x)
> >> Saurabh> gdb says: Cannot resolve function fn to any overloaded instance
> >> Saurabh> This used to work with gdb 7.2. The function signature completely
> >> Saurabh> matches the arguments so I dont know what it's complaining about.
> >>
> >> Please file a bug report.
> >
> > Done: http://sourceware.org/bugzilla/show_bug.cgi?id=15398
>
> Thank you. This was introduced in 7.2 with support for ADL. Looks like a
> bug in types_equal, which doesn't account for cv qualifiers.

It was introduced in 7.3. 7.2 works.

>
> >> Saurabh> 2. print k
> >> Saurabh> Let's say this prints 0x7ffb24
> >> Saurabh> call fn2(0x7ffb24)
> >> Saurabh> gdb again says: Cannot resolve function fn2 to any overloaded instance
> >> Saurabh> This also used to work with gdb 7.2. Here I can understand if
> >> Saurabh> promoting ints to arbitrary pointers is no longer supported.
> >>
> >> I was under the impression that we allowed this again, but it fails for
> >> me too. Please file another bug for this one.
> >
> > Done: http://sourceware.org/bugzilla/show_bug.cgi?id=15399
>
> What is "show check type"? If that is enabled/non-zero, gdb will not
> allow this conversion. If you disable it ("set check type 0"), it should
> work:
>
> (gdb) p fn2(0x7fffffffde14)
> Cannot resolve function fn2 to any overloaded instance
> (gdb) set check type 0

This does not work. show check type takes off/on; 0 gives an 
error to me. Neither off nor on print the value. Note that you need to 
compile with g++. Thanks. 		 	   		  
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Date: Thu, 25 Apr 2013 16:12:00 -0000
From: Keith Seitz <keiths@redhat.com>
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To: Saurabh T <saurabh@hotmail.com>
CC: "gdb@sourceware.org" <gdb@sourceware.org>
Subject: Re: Problem calling functions within gdb (version 7.5)
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On 04/25/2013 08:45 AM, Saurabh T wrote:
>> Thank you. This was introduced in 7.2 with support for ADL. Looks like a
>> bug in types_equal, which doesn't account for cv qualifiers.
>
> It was introduced in 7.3. 7.2 works.

Yes, sorry. My bad.

>> What is "show check type"? If that is enabled/non-zero, gdb will not
>> allow this conversion. If you disable it ("set check type 0"), it should
>> work:
>>
>> (gdb) p fn2(0x7fffffffde14)
>> Cannot resolve function fn2 to any overloaded instance
>> (gdb) set check type 0
>
> This does not work. show check type takes off/on; 0 gives an
> error to me. Neither off nor on print the value. Note that you need to
> compile with g++. Thanks.

I am using your example program with G++ 4.7.2 (Fedora 18 system compiler).

Ah, I think I may see the problem. This was fixed /after/ the 7.5 branch
was created, so it doesn't actually appear in an official release yet. I
use CVS HEAD, so I have that patch in my sources.

In that patch, we re-purpose the existing command "set/show check type",
and that is probably why it does nothing for you (because until now, it
never did do anything).

If you grep for "strict" in gdbtypes.c, do you get anything? If not,
your sources do not contain the patch from c++/13356
(http://sourceware.org/bugzilla/show_bug.cgi?id\x13356).

The easiest way to get the patch is to use the git mirror and use commit
e8370ca5. Or I can send it to you privately.

Keith