Commit dfdf54f2 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r285782: 

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r285782 | brad | 2016-11-01 18:39:01 -0700 (Tue, 01 Nov 2016) | 9 lines

Disable the use of std::call_once on OpenBSD with libstdc++.

It was noticed this caused performance regressions and deadlocks. PR30768.

Reorder the code to make it clearer what is tested.

PPC now disables the use of std::call_once only with libstdc++ with
the reordering of the code, as was the original intent.

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llvm-svn: 288075
parent 5e21eeb9

llvm/include/llvm/Support/Threading.h

+5 −5
Original line number Diff line number Diff line
@@ -20,11 +20,11 @@ 
#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.

#if defined(LLVM_ON_UNIX) &&                                                   \

    !(defined(__NetBSD__) && !defined(_LIBCPP_VERSION)) && !defined(__ppc__)

// std::call_once from libc++ is used on all Unix platforms. Other

// implementations like libstdc++ are known to have problems on NetBSD,

// OpenBSD and PowerPC.

#if defined(LLVM_ON_UNIX) && (defined(_LIBCPP_VERSION) ||                      \

    !(defined(__NetBSD__) || defined(__OpenBSD__) || defined(__ppc__)))

#define LLVM_THREADING_USE_STD_CALL_ONCE 1

#else

#define LLVM_THREADING_USE_STD_CALL_ONCE 0