RFR: 8253717: Relocate stack overflow code out of thread.hpp/cpp [v5]

[Thomas Stuefe]

On Wed, 7 Oct 2020 15:22:31 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> This change moves the significant amount of stack overflow related code (with ascii art!) out of thread files into a
>> new file.  Many of the functions are static functions and some go through JavaThread::_stack_overflow_state where
>> needed.   All functions are moved and not modified except for qualification.  I also added a delegating constructor to
>> JavaThread::JavaThread so reordered the assignments as initializers from JavaThread::initialize.
>> Tested with tier1-6 and builds on arm32, ppc, s390 and zero.
>
> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Added some const to StackOverflow declarations

One small nit, otherwise okay.

src/hotspot/share/runtime/stackOverflow.cpp line 38:

> 36: size_t StackOverflow::_stack_shadow_zone_size = 0;
> 37:
> 38: void StackOverflow::initialize_stack_zone_sizes(size_t alignment) {

I think you can remove the parameter and hard-code 4K inside this function. The reason is that the "StackXXXPages"
parameters are defined as "number of 4k units", not "number of pages".

-------------

Changes requested by stuefe (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/522