From ba0e4e45bcc60b6897cd5c8f96cc404981e5c2c2 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@cloudius-systems.com>
Date: Tue, 2 Jun 2015 13:22:35 +0300
Subject: [PATCH] future: disable inline continuations in debug mode

Inline continuations can hide bugs where a stack variable is captured by
reference.  Disable them in debug mode.
---
 core/future.hh | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/core/future.hh b/core/future.hh
index 625fc35cc2..62f6ed12cf 100644
--- a/core/future.hh
+++ b/core/future.hh
@@ -327,6 +327,13 @@ struct continuation final : task {
     future_state<T...> _state;
     Func _func;
 };
+
+#ifndef DEBUG
+static constexpr unsigned max_inlined_continuations = 256;
+#else
+static constexpr unsigned max_inlined_continuations = 1;
+#endif
+
 /// \endcond
 
 /// \brief promise - allows a future value to be made available at a later time.
@@ -586,7 +593,7 @@ private:
     futurize_t<Ret> then(Func&& func, Param&& param) noexcept {
         using futurator = futurize<Ret>;
         using P = typename futurator::promise_type;
-        if (state()->available() && (++future_avail_count % 256)) {
+        if (state()->available() && (++future_avail_count % max_inlined_continuations)) {
             try {
                 return futurator::apply(std::forward<Func>(func), param(std::move(*state())));
             } catch (...) {