Integrated: JDK-8254189: Improve comments for StackOverFlow and fix in_xxx() functions

[Thomas Stuefe]

On Thu, 22 Oct 2020 04:21:30 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.

This pull request has now been integrated.

Changeset: 4031cb41
Author:    Thomas Stuefe <stuefe at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/4031cb41
Stats:     102 lines in 2 files changed: 99 ins; 0 del; 3 mod

8254189: Improve comments for StackOverFlow and fix in_xxx() functions

Reviewed-by: dholmes, gziemski

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