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

[Coleen Phillimore]

On Tue, 6 Oct 2020 16:25:58 GMT, Daniel D. Daugherty <dcubed 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.
>
> src/hotspot/os/linux/os_linux.cpp line 2034:
> 
>> 2032:   if (!_stack_is_executable) {
>> 2033:     for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
>> 2034:       StackOverflow* sto = jt->stack_overflow_state();
> 
> So why use `sto` here when you use `overflow_state` above?
> The GitHub review UI makes this difference more obvious than webrev...
> 
> Update: In other source files, you use `overflow_state`.

I'll change it to overflow_state.  I should be consistent.  Fixed.

> src/hotspot/share/runtime/stackOverflow.cpp line 2:
> 
>> 1: /*
>> 2:  * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
> 
> You have this copyright as a range of years while stackOverflow.hpp is just 2020.

oops. fixed.

> src/hotspot/share/runtime/stackOverflow.hpp line 37:
> 
>> 35:   friend class JavaThread;
>> 36:  public:
>> 37:   // State of the stack guard pages for this thread.
> 
> The "this thread" part no longer reads as well...
> I don't have a suggested rewording...

// State of the stack guard pages for the containing thread.
?

> src/hotspot/share/runtime/thread.cpp line 2954:
> 
>> 2952:
>> 2953: void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
>> 2954:   // ignore is there is no stack
> 
> typo - s/is there/if there/

Fixed.  That code block showed up in the diff since I moved the function just above the one that called it.

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