From: Roman Popov <ripopov@gmail.com>
To: Simon Marchi <simon.marchi@polymtl.ca>
Cc: Martin Sebor <msebor@gmail.com>, Manfred <mx2927@gmail.com>,
gdb@sourceware.org, gcc@gcc.gnu.org
Subject: Re: gdb 8.x - g++ 7.x compatibility
Date: Mon, 05 Feb 2018 17:44:00 -0000 [thread overview]
Message-ID: <CAATAM3F_+ZDockv+UTZXrJhT5nH-1W4Qad=mW5dH+SSw0GHwzQ@mail.gmail.com> (raw)
In-Reply-To: <a1b77cdc201ce000661a147430ebd970@polymtl.ca>
Interestingly RTTI name also gives no guarantees:
http://en.cppreference.com/w/cpp/types/type_info/name
<< Returns an implementation defined null-terminated character string
containing the name of the type. No guarantees are given; in particular,
the returned string can be identical for several types and change between
invocations of the same program. >>
It probably makes sense to look how g++ implements
std::type_info::operator== . Probably there are some hints that GDB
algorithm can utilize.
Operator std::type_info::operator== must return true for equivalent types.
2018-02-05 8:59 GMT-08:00 Simon Marchi <simon.marchi@polymtl.ca>:
> On 2018-02-05 11:45, Martin Sebor wrote:
>
>> Yes, with auto, the type of the constant does determine the type
>> of the specialization of the template in the source code.
>>
>> In non-type template arguments, and more to the point I was making,
>> in diagnostics, the suffix shouldn't or doesn't need to be what
>> distinguishes the type of the template, even with auto. The part
>> "with auto IVAL = 10" in the message
>>
>> 'void foo<IVAL>::print() [with auto IVAL = 10]':
>>
>> would be far clearer if auto were replaced by the deduced type,
>> say along these lines:
>>
>> 'void foo<IVAL>::print() [with int IVAL = 10]':
>>
>> rather than relying on the suffix alone to distinguish between
>> different specializations of the template. That seems far too
>> subtle to me. But I think the diagnostic format is (or should
>> be) independent of the debug info.
>>
>
> That makes sense.
>
> With respect to the suffix, I keep coming back to the reality
>> that even if GCC were to change to emit a format that GDB can
>> interpret easily and efficiently, there still are other
>> compilers that emit a different format. So the conclusion
>> that a general solution that handles more than just one format
>> (at least for non-type template arguments without auto) seems
>> unescapable.
>>
>
> If there are other compilers we wanted to support for which we can't trust
> the template format, we could always ignore the template part of DW_AT_name
> specifically for them. But since g++ and gdb are part of the same project
> and are expected to work well and efficiently together, I would have hoped
> that we could agree on a format so that gdb would not have to do the extra
> work when parsing a g++-generated file (consequently the same format that
> libiberty's demangler produces).
>
> Given the problem I illustrated in my previous mail, I don't have a
> general solution to the problem to propose.
>
> Simon
>
next prev parent reply other threads:[~2018-02-05 17:44 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-03 3:17 Roman Popov
2018-02-03 3:57 ` carl hansen
2018-02-03 4:54 ` Simon Marchi
2018-02-03 5:02 ` Roman Popov
2018-02-03 6:43 ` Roman Popov
2018-02-03 14:20 ` Paul Smith
2018-02-03 17:18 ` Roman Popov
2018-02-03 18:36 ` Manfred
2018-02-04 5:02 ` Simon Marchi
2018-02-04 17:09 ` Manfred
2018-02-04 19:17 ` Martin Sebor
2018-02-05 5:07 ` Simon Marchi
2018-02-05 16:45 ` Martin Sebor
2018-02-05 16:59 ` Simon Marchi
2018-02-05 17:44 ` Roman Popov [this message]
2018-02-05 20:08 ` Jonathan Wakely
2018-02-05 20:10 ` Roman Popov
2018-02-05 20:12 ` Jonathan Wakely
2018-02-05 20:17 ` Roman Popov
2018-02-06 3:52 ` Martin Sebor
2018-02-07 7:21 ` Daniel Berlin
2018-02-07 13:44 ` Simon Marchi
2018-02-07 15:07 ` Manfred
2018-02-07 15:16 ` Jonathan Wakely
2018-02-07 16:19 ` Manfred
2018-02-07 16:26 ` Michael Matz
2018-02-07 16:43 ` Simon Marchi
2018-02-07 16:51 ` Jonathan Wakely
2018-02-07 17:03 ` Simon Marchi
2018-02-07 17:08 ` Jonathan Wakely
2018-02-07 17:20 ` Simon Marchi
2018-02-07 17:30 ` Jonathan Wakely
2018-02-07 18:28 ` Simon Marchi
2018-02-08 11:26 ` Michael Matz
2018-02-08 14:05 ` Paul Smith
2018-02-08 14:07 ` Jonathan Wakely
2018-02-07 17:31 ` Marc Glisse
2018-02-07 17:04 ` Daniel Berlin
2018-02-07 17:11 ` Daniel Berlin
2018-02-07 22:00 ` Nathan Sidwell
2018-02-07 20:29 ` Tom Tromey
2018-02-08 15:05 ` Richard Biener
2018-03-01 20:18 ` Roman Popov
2018-03-01 20:26 ` Andrew Pinski
2018-03-01 21:03 ` Jason Merrill
2018-03-02 23:06 ` Roman Popov
2018-03-03 4:01 ` Roman Popov
2018-03-04 4:28 ` Daniel Berlin
2018-02-05 11:05 ` Jonathan Wakely
2018-02-07 15:19 ` Jonathan Wakely
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