Re: [PATCH,RFC,V3 0/5] Support for CTF in GCC

[Jeff Law <law@redhat.com>]

On 7/9/19 5:25 PM, Segher Boessenkool wrote:
> On Fri, Jul 05, 2019 at 07:28:12PM +0100, Nix wrote:
>> On 5 Jul 2019, Richard Biener said:
>>
>>> On Fri, Jul 5, 2019 at 12:21 AM Indu Bhagat <indu.bhagat@oracle.com> wrote:
>>>> CTF, at this time, is type information for entities at global or file scope.
>>>> This can be used by online debuggers, program tracers (dynamic tracing); More
>>>> generally, it provides type introspection for C programs, with an optional
>>>> library API to allow them to get at their own types quite more easily than
>>>> DWARF. So, the umbrella usecases are - all C programs that want to introspect
>>>> their own types quickly; and applications that want to introspect other
>>>> programs's types quickly.
>>>
>>> What makes it superior to DWARF stripped down to the above feature set?
>>
>> Increased compactness.
> 
> Does CTF support something like -fasynchronous-unwind-tables?  You need
> that to have any sane debugging on many platforms.  Without it, you
> even have only partial backtraces, on most architectures/ABIs anyway.
I'd be suprised if it did since you need location information.  FWIW,
low level libraries like glibc depend on this stuff to support cancellation.

jeff