[llvm-dev] A potential race on StaticList in RegisterManagedStatic

[Viacheslav Nikolaev via llvm-dev]

Though it won't actually help to guard this: while (StaticList) - a fence
here is needed...

On Mon, Dec 26, 2016 at 9:20 AM, Viacheslav Nikolaev <
viacheslav.nikolaev at gmail.com> wrote:

> Ptr member of ManagedStaticBase is now atomic.
> In ManagedStaticBase::RegisterManagedStatic we have such code:
>
>       void *Tmp = Creator();
>
>       Ptr.store(Tmp, std::memory_order_release);
>       DeleterFn = Deleter;
>
>       // Add to list of managed statics.
>       Next = StaticList;
>       StaticList = this;
>
>
> StaticList is not atomic and not guarded by any fence.
> The same applies to the members DeleterFn and Next.
>
> Doesn't it seem reasonable to change the code to
>
>       DeleterFn = Deleter;
>
>       // Add to list of managed statics.
>       Next = StaticList;
>       StaticList = this;
>       Ptr.store(Tmp, std::memory_order_release);
>
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