Fix profiler sync issue

[davmason]

Because there was not a named variable some compilers were optimizing out the RAII guard.

[ghost]

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Issue Details

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Because there was not a named variable some compilers were optimizing out the RAII guard.

Author:	davmason
Assignees:	davmason
Labels:	area-Diagnostics-coreclr
Milestone:	-

[hoyosjs]

Oh man...

[GSPP]

Is this a legal optimization? It seems not.

[davmason]

@GSPP With the first version ShutdownGuard(); it was introducing a temporary and after the change ShutdownGuard shutdownGuard; it is introducing a named variable. The standard says in 3.7.3 that:

If a variable with automatic storage duration has initialization or a destructor with side effects, it shall not be destroyed before the end of its block, nor shall it be eliminated as an optimization even if it appears to be unused, except that a class object or its copy/move may be eliminated as specified in 12.8.

The key here is that the temporary does not have automatic storage duration, but the named variable does. So it seems like a perfectly legal optimization to me

[GSPP]

Thanks for explaining. This was beyond my knowledge of C++.