RFR: 8230877: Rename THREAD_LOCAL_DECL to thread_local

[Per Liden]

On 9/12/19 12:12 AM, Kim Barrett wrote:
>> On Sep 11, 2019, at 5:37 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
>> Instead for VS we probably need to do an MSVC version check to decide
>> whether to define thread_local to __declspec(thread), but I don't know which
>> version of VS starts providing it natively.  Either that or prune the set of
>> (at least purportedly) supported versions somewhat.
> 
> According to boost.config and various other places I found, it appears
> thread_local first shows up in Visual Studio 2015. So having a
> __declspec(thread) definition protected with "#if _MSC_VER < 1900" should do
> the trick.
> 

I sort of came to the same conclusion. According to this table [1], 
there's "Partial" support in VS2010, and full support in VS2015. No 
details on what "Partial" means. Some additional googling vaguely 
suggests that "Partial" refers to support for "__declspec(thread)" and 
full support would be "thread_local", but I can't find any official 
document saying that.

Defining thread_local for pre-VS2015 (_MSC_VER < 1900) seems like a 
reasonable way forward.

Updated webrev: http://cr.openjdk.java.net/~pliden/8230877/webrev.1

/Per

[1] 
https://docs.microsoft.com/en-us/previous-versions/hh567368(v=vs.140)?redirectedfrom=MSDN#c11-core-language-features-table-concurrency