[PATCH] Disable use of std::call_once on OpenBSD with libstdc++

[Brad Smith via llvm-commits]

Disable the use of std::call_once on OpenBSD with libstc++. It was noticed this caused
performance regressions and deadlocks.

https://github.com/rust-lang/rust/issues/36905
-------------- next part --------------
Index: include/llvm/Support/Threading.h
===================================================================
--- include/llvm/Support/Threading.h	(revision 284299)
+++ include/llvm/Support/Threading.h	(working copy)
@@ -20,11 +20,13 @@
 #include <ciso646> // So we can check the C++ standard lib macros.
 #include <functional>
 
-// We use std::call_once on all Unix platforms except for NetBSD with
-// libstdc++. That platform has a bug they are working to fix, and they'll
-// remove the NetBSD checks once fixed.
+// We use std::call_once on all Unix platforms except for NetBSD / OpenBSD with
+// libstdc++. Those platforms have bugs they are working to fix, and they will
+// remove the checks once fixed.
 #if defined(LLVM_ON_UNIX) &&                                                   \
-    !(defined(__NetBSD__) && !defined(_LIBCPP_VERSION)) && !defined(__ppc__)
+    !(defined(__NetBSD__) && !defined(_LIBCPP_VERSION)) &&                     \
+    !(defined(__OpenBSD__) && !defined(_LIBCPP_VERSION)) &&                    \
+    !defined(__ppc__)
 #define LLVM_THREADING_USE_STD_CALL_ONCE 1
 #else
 #define LLVM_THREADING_USE_STD_CALL_ONCE 0