Switch std::call_once to llvm::call_once

Summary:
The std::call_once implementation in libstdc++ has problems on few systems: NetBSD, OpenBSD and Linux PPC. LLVM ships with a homegrown implementation llvm::call_once to help on these platforms.

This change is required in the NetBSD LLDB port. std::call_once with libstdc++ results with crashing the debugger.

Sponsored by <The NetBSD Foundation>

Reviewers: labath, joerg, emaste, mehdi_amini, clayborg

Reviewed By: labath, clayborg

Subscribers: #lldb

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D29288

llvm-svn: 294202

1 files changed, 3 insertions, 2 deletions

diff --git a/lldb/source/Commands/CommandObjectPlatform.cpp b/lldb/source/Commands/CommandObjectPlatform.cpp
index f6891d77ec5..efce4a058bb 100644
--- a/lldb/source/Commands/CommandObjectPlatform.cpp
+++ b/lldb/source/Commands/CommandObjectPlatform.cpp
@@ -29,6 +29,7 @@
 #include "lldb/Target/Process.h"
 
 #include "llvm/ADT/SmallString.h"
+#include "llvm/Support/Threading.h"
 
 using namespace lldb;
 using namespace lldb_private;
@@ -1248,8 +1249,8 @@ protected:
   public:
     CommandOptions()
         : Options(), match_info(), show_args(false), verbose(false) {
-      static std::once_flag g_once_flag;
-      std::call_once(g_once_flag, []() {
+      static llvm::once_flag g_once_flag;
+      llvm::call_once(g_once_flag, []() {
         PosixPlatformCommandOptionValidator *posix_validator =
             new PosixPlatformCommandOptionValidator();
         for (auto &Option : g_platform_process_list_options) {