[cfe-dev] Clang generates wrong RTTI or Debug info?

[Roman Popov via cfe-dev]

I've put the same question on stackoverflow:
https://stackoverflow.com/questions/48469750/debugging-
clang-generated-rtti-code-with-gdb

Maybe GDB is the problem, not Clang?


2018-01-25 21:03 GMT-08:00 Roman Popov <ripopov at gmail.com>:

> Hello,
>
> I'm using Clang++ together with GDB. I've noticed that for some
> polymorphic classes GDB does not shows correct dynamic type.  After some
> investigation it turned out that Clang puts different typenames in DWARF
> and RTTI :
>
> I have a template class:
>
> template< class T, sc_writer_policy POL>
> class sc_signal : public sc_object
>
> where sc_writer_policy is an enum:
>
> enum sc_writer_policy
> {
>   SC_ONE_WRITER        = 0,
>   SC_MANY_WRITERS      = 1,
>   SC_UNCHECKED_WRITERS = 3
> };
>
>
> When I debug polymorphic objects of this class I got GDB errors like this:
>
> warning: RTTI symbol not found for class 'sc_core::sc_signal<int,
> (sc_core::sc_writer_policy)0>'
>
>
> The source of the problem is that it type name seems to be saved
> differently in RTTI and Debug info.
>
> From GDB:
> (gdb) info types sc_signal<int
> All types matching regular expression "sc_signal<int":
>
> *sc_core::sc_signal<int, sc_core::SC_ONE_WRITER>*
>
> Using RTTI:
>
> cout << typeid(*obj).name();
> N7sc_core9sc_signalIiLNS_16*sc_writer_policyE0*EEE
>
> So in RTTI we have mangled sc_core::sc_signal<int,
> (sc_core::sc_writer_policy)0>
>
>
> Is it possible to make Clang emitting same type-name in both cases?
>
>
> Originally I've discovered this issue with Clang++5.0.  Just tried with
> Clang++6.0 and it is still there.
> g++ 5.4 and g++7.0 both work fine, (sc_core::sc_signal<int,
> (sc_core::sc_writer_policy)0> is generated in both cases)
>
> Thanks,
> Roman
>
>
>
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