Replace static_lazy<> with normal statics

[jonwis]

wil/include/wil/Tracelogging.h

Lines 188 to 204 in eb9eb35

	template <class T>
	class static_lazy
	{
	public:
	void __cdecl cleanup() WI_NOEXCEPT
	{
	void* pVoid;
	BOOL pending;
	// If object is being constructed on another thread, wait until construction completes.
	// Need a memory barrier here (see get() and ~Completer below) so use the result that we
	// get from InitOnceBeginInitialize(..., &pVoid, ...)
	if (::InitOnceBeginInitialize(&m_initOnce, INIT_ONCE_CHECK_ONLY, &pending, &pVoid) && !pending)
	{
	static_cast<T*>(pVoid)->~T();
	}
	}

According to https://learn.microsoft.com/en-us/cpp/cpp/storage-classes-cpp?view=msvc-170, function-local "magic statics" are fully supported.

Instead of defining a custom static_lazy type, use the built-in support.

1. Remove static_lazy<>
2. On line 2283ish in the Instance() method:

static TraceLoggingClassName* Instance() WI_NOEXCEPT \
{ \
    static TraceLoggingClassName wrapper; \
    return wrapper; \
} \
friend class wil::details::static_lazy<TraceLoggingClassName>;

[ChrisGuzak]

magic statics have some overhead that some components, dlls that are loaded in many processes, what to avoid.
using wil::init_once avoids that, at the cost of more complicated code. is that your understanding?

[jonwis]

magic statics have some overhead that some components, dlls that are loaded in many processes, what to avoid. using wil::init_once avoids that, at the cost of more complicated code. is that your understanding?

I'd like to understand that overhead and take feature requests to the CRT team if necessary. Magic statics are the intended language tool for this problem. Do you have examples of swapping init_once to magic statics so we can see the impact?

[sylveon]

I was under the impression that statics use InitOnceBeginInitialize or something equivalent, and that using static_lazy would basically just be replacing automatic overhead with manual overhead.

You're also already paying that cost anyways, because this is how it's used currently:

wil/include/wil/Tracelogging.h

Line 2287 in 6f60a1b

static wil::details::static_lazy<TraceLoggingClassName> wrapper; \