[Lldb-commits] [PATCH] D29288: Switch std::call_once to llvm::call_once

[Pavel Labath via Phabricator via lldb-commits]

labath added inline comments.


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Comment at: include/lldb/Core/Debugger.h:379
   lldb::ListenerSP m_forward_listener_sp;
-  std::once_flag m_clear_once;
+  llvm::once_flag m_clear_once;
 
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The code in llvm says you should only ever use the LLVM_DEFINE_ONCE_FLAG to declare flags. I am guessing it's because it forces the `static` keyword into the declaration, which in turn guarantees your object will be zero-initialized by the linker. If you declare the flag as a local variable like this, it will be initialized to a random value, and you will have a fun time debugging issues in the future (it will only affect netbsd, as std::call_once platforms will still be correctly initialized).


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Comment at: source/Core/ModuleList.cpp:648
 static ModuleList &GetSharedModuleList() {
   static ModuleList *g_shared_module_list = nullptr;
+  LLVM_DEFINE_ONCE_FLAG(g_once_flag);
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This could be simplified to:
```static ModuleList *g_shared_module_list = new ModuleList();```

It's only written this way because MSVC at one point did not support thread-safe statics.


Repository:
  rL LLVM

https://reviews.llvm.org/D29288