Remove remnants of support code for an upwards growing stack.

[Mark Lam]

We haven't supported an upwards growing stack in years, and a lot of code has since been written specifically with only a downwards growing stack in mind (e.g. the LLInt, the JITs).  Also, all our currently supported platforms use a downward growing stack.

We should remove the remnants of support code for an upwards growing stack.  The presence of that code is deceptive in that it conveys support for an upwards growing stack where this hasn't been the case in years.

[Mark Lam]

Created attachment 383022 [details]
proposed patch.

[Yusuke Suzuki]

Comment on attachment 383022 [details]
proposed patch.

r=me

[Mark Lam]

Comment on attachment 383022 [details]
proposed patch.

View in context: https://bugs.webkit.org/attachment.cgi?id=383022&action=review

Thanks for the review.

> Source/WTF/wtf/StackBounds.h:113
> +        ASSERT(m_bound <= m_origin);

This one is redundant from a partial edit.  I opted to go with the private isGrowingDownwards() methods instead because it documents at a glance what we're asserting here.  I'll remove this redundant line before landing.

[Mark Lam]

Landed in r252177: <http://trac.webkit.org/r252177>.

[Radar WebKit Bug Importer]

<rdar://problem/56973526>