RFR: JDK-8254189: Improve comments for StackOverFlow and fix in_xxx() functions [v3]

[David Holmes]

On Wed, 28 Oct 2020 17:20:07 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Hi,
>> 
>> may I please have reviews for this small cleanup / fix?
>> 
>> While reviewing JDK-8253717 it was found that comments would help with understanding the StackOverFlow class. Especially the fact that the various _base_ are actually pointing outside their respective zone, since the stack grows downward and a zone (and the stack itself) range is [end, base). If you don't look at this code daily it can be surprising.
>> 
>> This also fixes some small off-by-one errors in various "in_stack_xxx_zone()" methods which test whether a given address is inside a zone and gave wrong results for address=base since base points outside its zone. This had the effect that an address could be in multiple zones.
>> 
>> Finally it adds a small gtest which tests the StackOverFlow methods.
>
> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Feedback Gerard

Marked as reviewed by dholmes (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/795