[PATCH] D127623: [Debug] [Coroutine] Adjust the scope and name for coroutine frame

[Chuanqi Xu via Phabricator via llvm-commits]

ChuanqiXu added a comment.

John gives the suggestion for the DIName of coroutine frame in C++ version in https://github.com/itanium-cxx-abi/cxx-abi/issues/142::

  <local-name> ::= Z <function encoding> E <entity name> [<discriminator>]

So that the frame name in the example would be `_ZZL9coro_taskiE13coro_frame_ty`. And both `C++filt` and `llvm-cxxfilt` would detangle it as we want as `coro_task(int)::coro_frame_ty`. I guess this is what @dblaikie want initially. Then John throws another problem that the solution above is not suit for C-style names. Although we're talking about C++ coroutine only, we could use `extern "C"` in C++ to prevent mangling actually. (It should be rare actually. Since the use of C++ coroutines generally require the involvement of coroutine types like 'lazy' or 'generator'. But such coroutine types are not C compatible generally.)

Then @avogelsgesang and @palves throw another requirement to avoid to see mangled names in gdb. I feel like this might not be necessary at first since the users wouldn't see the linkage name from our use experience. Although @palves throws the solution for locals, but I found it doesn't work local scope types:

  C++
  int main() {
    struct S {
      int a;
      bool b;
    };
    S s;
  }

  (gdb) p main::s
  $2 = {a = -8000, b = 255}
  (gdb) p main::S
  A syntax error in expression, near `'.
  (gdb) p 'main'::S
  A syntax error in expression, near `'.
  (gdb) p 'main()'::S
  A syntax error in expression, near `'.

I am not sure if it is unable to make.

---

So there are 2 problems we saw:
(1) How do we handle unmangled names?
(2) Do we need to enable the user to print the type without knowing mangled names?

For the first problem, I prefer to use '.' as the separator since @palves gives reason why I failed earlier. And for the second problem, my answer is no due to above reasons. But it would be good if we have solutions.


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