[libc++] Remove race condition in std::async
Summary:
The state associated to the future was set in one thread (with synchronization)
but read in another thread without synchronization, which led to a data race.
https://bugs.llvm.org/show_bug.cgi?id=38181
rdar://problem/42548261
Reviewers: mclow.lists, EricWF
Subscribers: christof, dexonsmith, cfe-commits
Differential Revision: https://reviews.llvm.org/D51170
llvm-svn: 340608
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 616ef1863faef8dedf2e6bfbaee7569d84f11e35
diff --git a/src/future.cpp b/src/future.cpp
index 07e4602..cbcd2e7 100644
--- a/src/future.cpp
+++ b/src/future.cpp
@@ -179,10 +179,7 @@
future<void>::future(__assoc_sub_state* __state)
: __state_(__state)
{
- if (__state_->__has_future_attached())
- __throw_future_error(future_errc::future_already_retrieved);
- __state_->__add_shared();
- __state_->__set_future_attached();
+ __state_->__attach_future();
}
future<void>::~future()