From 5764067c8099e8552366b3875abcf757154fcc1a Mon Sep 17 00:00:00 2001
From: John Biddiscombe <biddisco@cscs.ch>
Date: Thu, 19 Oct 2017 14:48:23 +0100
Subject: [PATCH] Debugging async continuation problem

---
 .../resource_partitioner/guided_pool_test.cpp | 21 ++++++--
 .../executors/guided_pool_executor.hpp        | 49 +++++++++++++++++++
 .../threads/executors/pool_executor.cpp       |  2 +-
 3 files changed, 67 insertions(+), 5 deletions(-)

diff --git a/examples/resource_partitioner/guided_pool_test.cpp b/examples/resource_partitioner/guided_pool_test.cpp
index 9ef5b3369ec4..9404e0df90d6 100644
--- a/examples/resource_partitioner/guided_pool_test.cpp
+++ b/examples/resource_partitioner/guided_pool_test.cpp
@@ -116,13 +116,20 @@ int hpx_main(boost::program_options::variables_map& vm)
     std::size_t num_threads = hpx::get_num_worker_threads();
     std::cout << "HPX using threads = " << num_threads << std::endl;
 
+    std::cout << "----------------------------------------------" << std::endl;
+    std::cout << "Testing async guided exec " << std::endl;
+    std::cout << "----------------------------------------------" << std::endl;
     // we must specialize the numa callback hint for the function type we are invoking
     using hint_type1 = pool_numa_hint<decltype(&async_guided)>;
     // create an executor using that hint type
     hpx::threads::executors::guided_pool_executor<hint_type1> guided_exec(CUSTOM_POOL_NAME);
-    // invoke an asyn function using our numa hint executor
+    // invoke an async function using our numa hint executor
     hpx::future<void> gf1 = hpx::async(guided_exec, &async_guided, 5, true, "Guided function");
+    gf1.get();
 
+    std::cout << "----------------------------------------------" << std::endl;
+    std::cout << "Testing async guided exec lambda" << std::endl;
+    std::cout << "----------------------------------------------" << std::endl;
     // specialize the numa hint callback for a lambda type invocation
     // the args of the async lambda must match the args of the hint type
     using hint_type2 = pool_numa_hint<int, double, const std::string &>;
@@ -136,18 +143,24 @@ int hpx_main(boost::program_options::variables_map& vm)
             return 3.1415;
         },
         5, 2.718, "Guided function 2");
+    gf2.get();
 
+    std::cout << "----------------------------------------------" << std::endl;
+    std::cout << "Testing async guided exec continuation" << std::endl;
+    std::cout << "----------------------------------------------" << std::endl;
     // specialize the numa hint callback for another lambda type invocation
     // the args of the async lambda must match the args of the hint type
     using hint_type3 = pool_numa_hint<double>;
     // create an executor using the numa hint type
     hpx::threads::executors::guided_pool_executor<hint_type3> guided_cont_exec(CUSTOM_POOL_NAME);
     // invoke the lambda asynchronously and use the numa executor
-    auto new_future = gf2.then(guided_cont_exec, [](hpx::future<double> &&df) {
-        double d = df.get();
+    auto new_future = hpx::async([]() -> double { return 3.1415;} ).then(
+        guided_cont_exec, hpx::util::unwrapping([](double df)
+    {
+        double d = df; // .get();
         std::cout << "received a double of value " << d << std::endl;
         return d*2;
-    });
+    }));
 
     new_future.get();
 
diff --git a/hpx/runtime/threads/executors/guided_pool_executor.hpp b/hpx/runtime/threads/executors/guided_pool_executor.hpp
index 507250adf852..94cbe38eb3fc 100644
--- a/hpx/runtime/threads/executors/guided_pool_executor.hpp
+++ b/hpx/runtime/threads/executors/guided_pool_executor.hpp
@@ -20,6 +20,53 @@
 
 #include <hpx/config/warnings_prefix.hpp>
 
+//
+#include <typeinfo>
+
+#ifdef __GNUG__
+# include <cstdlib>
+# include <cxxabi.h>
+#endif
+
+
+// ------------------------------------------------------------------
+// helper to demangle type names
+// ------------------------------------------------------------------
+#ifdef __GNUG__
+std::string demangle(const char* name)
+{
+    // some arbitrary value to eliminate the compiler warning
+    int status = -4;
+    std::unique_ptr<char, void(*)(void*)> res {
+        abi::__cxa_demangle(name, NULL, NULL, &status),
+                std::free
+    };
+    return (status==0) ? res.get() : name ;
+}
+#else
+// does nothing if not g++
+std::string demangle(const char* name) {
+    return name;
+}
+#endif
+
+inline std::string print_type() { return ""; }
+
+template <class T>
+inline std::string print_type()
+{
+    return demangle(typeid(T).name());
+}
+
+template<typename T, typename... Args>
+inline std::string print_type(T&& head, Args&&... tail)
+{
+    std::string temp = print_type<T>();
+    std::cout << temp << std::endl;
+    return print_type(std::forward<Args>(tail)...);
+}
+
+
 namespace hpx { namespace threads { namespace executors
 {
     struct bitmap_storage
@@ -51,6 +98,8 @@ namespace hpx { namespace threads { namespace executors
             int domain = numa_function_(ts...);
             std::cout << "The numa domain is " << domain << "\n";
 
+            print_type(ts...);
+
             // now we must forward the task on to the correct dispatch function
             typedef typename util::detail::invoke_deferred_result<F, Ts...>::type
                 result_type;
diff --git a/src/runtime/threads/executors/pool_executor.cpp b/src/runtime/threads/executors/pool_executor.cpp
index d6d8d36f4b7e..287f43f331bb 100644
--- a/src/runtime/threads/executors/pool_executor.cpp
+++ b/src/runtime/threads/executors/pool_executor.cpp
@@ -69,7 +69,7 @@ namespace hpx { namespace threads { namespace executors
             threads::thread_schedule_hint schedulehint,
             error_code& ec)
         {
-            std::cout << "pool exeutor received hint " << schedulehint << std::endl;
+            std::cout << "pool executor received hint " << schedulehint << std::endl;
             // create a new thread
             thread_init_data data(
                 util::bind(