GCC testcase for DPP coroutine

dpp-simple.C

// Override default options.
// { dg-do run }
// { dg-options "-std=gnu++20 -fcoroutines  -Wall -fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations   -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_DEBUG  -DAVX_TYPE=2 -DDPP_BUILD -DDPP_OS=Linux -DHAVE_VOICE -DNOMINMAX -I/home/agpotter/git/DPP/library/../mlspp/include -I/home/agpotter/git/DPP/library/../mlspp/lib/bytes/include -I/home/agpotter/git/DPP/library/../mlspp/lib/hpke/include -I/home/agpotter/git/DPP/library/../include -I/home/agpotter/git/DPP/library/../include/dpp -pthread " }
//
// filename: gcc/testsuite/g++.dg/coroutines/dpp-simple.C
// run via: make -C gcc check-g++ RUNTESTFLAGS=dg.exp=dpp-simple.C
//
#include <thread>
#include <iostream>
#include <dpp/dpp.h>
#include <coroutine>

struct canary {
  std::string name;
  canary(std::string_view name) : name(name) { std::cerr << "Canary '" << name << "' is born\n"; }
  canary(const canary& other) { name = "copied " + other.name;  std::cerr << "Canary '" << name << "' is born\n";}
  ~canary() { std::cerr << "Canary '" << name << "' is dead\n"; name = "DESTROYED CANARY?!"; }
};

struct simple_awaitable {
  volatile int value{};
  int result{};
  canary c{"simple_awaitable"};

  bool await_ready() const noexcept {
    return false;
  }

  template <typename T>
  void await_suspend(std::coroutine_handle<T> handle) {
    std::cerr << "simple_awaitable::await_suspend(): Got handle address " << handle.address() << "\n";
    std::thread th([this, handle, c = canary{"thread-lambda capture"}]() mutable {
      auto _ = canary{"thread stack variable"};
      std::cerr << "Inside simple_awaitable::await_suspend thread\n";
      std::this_thread::sleep_for(std::chrono::seconds(5));
      std::cerr << "Inside simple_awaitable::await_suspend thread: Finished 5s sleep\n";
      result = value;
      try {
        std::cerr << "Inside simple_awaitable::await_suspend thread: About to resume handle address " << handle.address() << "\n";
        handle.resume();
      } catch (const std::exception &) {
        /* no exception should be caught */
        std::cerr << "Inside simple_awaitable::await_suspend thread: went to exception\n";
      }
    });
    std::cerr << "Inside simple_awaitable::await_suspend, about to detach thread\n";
    th.detach();
  }

  int await_resume() const noexcept {
	std::cerr << "simple_awaitable::await_resume()\n";
    return result;
  }
};


dpp::task<void> task_offline_test() {
  std::cerr << "task_offline_test(): co_await simple_awaitable...\n";
  if (int ret = co_await simple_awaitable{42}; ret != 42) {
    std::cerr << "failed simple awaitable: expected return value not 42\n";
  }
  std::cerr << "task_offline_test(): simple_awaitable has returned, about to co_return myself. (simple_awaitable is destroyed now)\n";
  co_return;
}


int main()
{
  []() -> dpp::job {
	co_await task_offline_test();
  }();
  std::cerr << "main(): resuming execution.\n";

  std::this_thread::sleep_for(std::chrono::seconds(10));

  std::cerr << "main(): Sleep completed, we didn't crash yet? You fixed the problem.\n";

  return 0;
}