RFR: 8254723: add diagnostic command to write Linux perf map file [v2]

[Xin Liu]

On Tue, 27 Oct 2020 17:08:18 GMT, Xin Liu <xliu at openjdk.org> wrote:

>> Nick Gasson has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update for review comments
>
> src/hotspot/share/code/codeCache.cpp line 1566:
> 
>> 1564: 
>> 1565:   char fname[32];
>> 1566:   jio_snprintf(fname, sizeof(fname), "/tmp/perf-%d.map", os::current_process_id());
> 
> if you don't use #ifdef LINUX, this line needs a cross-platform temp.

I would like to take back this. I've seen that `CodeCache::write_perf_map` is wrapped by #ifdef LINUX. 
I read the older revision of change.

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PR: https://git.openjdk.java.net/jdk/pull/760