[Lldb-commits] [lldb] r284601 - Simplify GetGlobalProperties functions of Thread/Process/Target

[Zachary Turner via lldb-commits]

This was using call_once because msvc didn't support function local static
thread safe initialization. But it does now in msvc 2015.

Can you fix HostInfoBase `g_flags` while you're at it?
On Wed, Oct 19, 2016 at 8:21 AM Pavel Labath via lldb-commits <
lldb-commits at lists.llvm.org> wrote:

> Author: labath
> Date: Wed Oct 19 10:12:45 2016
> New Revision: 284601
>
> URL: http://llvm.org/viewvc/llvm-project?rev=284601&view=rev
> Log:
> Simplify GetGlobalProperties functions of Thread/Process/Target
>
> Summary:
> "Initialization of function-local statics is guaranteed to occur only once
> even when called from
> multiple threads, and may be more efficient than the equivalent code using
> std::call_once."
> <http://en.cppreference.com/w/cpp/thread/call_once>
>
> I'd add that it's also more readable.
>
> Reviewers: clayborg, zturner
>
> Subscribers: lldb-commits
>
> Differential Revision: http://reviews.llvm.org/D17710
>
> Modified:
>     lldb/trunk/source/Target/Process.cpp
>     lldb/trunk/source/Target/Target.cpp
>     lldb/trunk/source/Target/Thread.cpp
>
> Modified: lldb/trunk/source/Target/Process.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/Process.cpp?rev=284601&r1=284600&r2=284601&view=diff
>
> ==============================================================================
> --- lldb/trunk/source/Target/Process.cpp (original)
> +++ lldb/trunk/source/Target/Process.cpp Wed Oct 19 10:12:45 2016
> @@ -812,11 +812,8 @@ Process::~Process() {
>  const ProcessPropertiesSP &Process::GetGlobalProperties() {
>    // NOTE: intentional leak so we don't crash if global destructor chain
> gets
>    // called as other threads still use the result of this function
> -  static ProcessPropertiesSP *g_settings_sp_ptr = nullptr;
> -  static std::once_flag g_once_flag;
> -  std::call_once(g_once_flag, []() {
> -    g_settings_sp_ptr = new ProcessPropertiesSP(new
> ProcessProperties(nullptr));
> -  });
> +  static ProcessPropertiesSP *g_settings_sp_ptr =
> +      new ProcessPropertiesSP(new ProcessProperties(nullptr));
>    return *g_settings_sp_ptr;
>  }
>
>
> Modified: lldb/trunk/source/Target/Target.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/Target.cpp?rev=284601&r1=284600&r2=284601&view=diff
>
> ==============================================================================
> --- lldb/trunk/source/Target/Target.cpp (original)
> +++ lldb/trunk/source/Target/Target.cpp Wed Oct 19 10:12:45 2016
> @@ -2643,11 +2643,8 @@ void Target::RunStopHooks() {
>  const TargetPropertiesSP &Target::GetGlobalProperties() {
>    // NOTE: intentional leak so we don't crash if global destructor chain
> gets
>    // called as other threads still use the result of this function
> -  static TargetPropertiesSP *g_settings_sp_ptr = nullptr;
> -  static std::once_flag g_once_flag;
> -  std::call_once(g_once_flag, []() {
> -    g_settings_sp_ptr = new TargetPropertiesSP(new
> TargetProperties(nullptr));
> -  });
> +  static TargetPropertiesSP *g_settings_sp_ptr =
> +      new TargetPropertiesSP(new TargetProperties(nullptr));
>    return *g_settings_sp_ptr;
>  }
>
>
> Modified: lldb/trunk/source/Target/Thread.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Target/Thread.cpp?rev=284601&r1=284600&r2=284601&view=diff
>
> ==============================================================================
> --- lldb/trunk/source/Target/Thread.cpp (original)
> +++ lldb/trunk/source/Target/Thread.cpp Wed Oct 19 10:12:45 2016
> @@ -58,11 +58,8 @@ using namespace lldb_private;
>  const ThreadPropertiesSP &Thread::GetGlobalProperties() {
>    // NOTE: intentional leak so we don't crash if global destructor chain
> gets
>    // called as other threads still use the result of this function
> -  static ThreadPropertiesSP *g_settings_sp_ptr = nullptr;
> -  static std::once_flag g_once_flag;
> -  std::call_once(g_once_flag, []() {
> -    g_settings_sp_ptr = new ThreadPropertiesSP(new
> ThreadProperties(true));
> -  });
> +  static ThreadPropertiesSP *g_settings_sp_ptr =
> +      new ThreadPropertiesSP(new ThreadProperties(true));
>    return *g_settings_sp_ptr;
>  }
>
>
>
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