Bug 190503 – Use currentStackPointer more

• Component: New Bugs
• Status: RESOLVED FIXED

[Yusuke Suzuki]

Use currentStackPointer more

[Yusuke Suzuki]

Created attachment 352115 [details]
Patch

[Saam Barati]

Comment on attachment 352115 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=352115&action=review

> Source/WTF/wtf/StackBounds.cpp:55
> +    volatile uint8_t* stackValue = bitwise_cast<uint8_t*>(currentStackPointer());

Does this work on debug builds where this is an actual function call?

[Yusuke Suzuki]

(In reply to Saam Barati from comment #2)
> Comment on attachment 352115 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=352115&action=review
> 
> > Source/WTF/wtf/StackBounds.cpp:55
> > +    volatile uint8_t* stackValue = bitwise_cast<uint8_t*>(currentStackPointer());
> 
> Does this work on debug builds where this is an actual function call?

Yeah, at least in x64, it works :)

[Yusuke Suzuki]

Landed in https://trac.webkit.org/r237059

[Radar WebKit Bug Importer]

<rdar://problem/45213815>

[Mark Lam]

(In reply to Yusuke Suzuki from comment #3)
> (In reply to Saam Barati from comment #2)
> > Comment on attachment 352115 [details]
> > Patch
> > 
> > View in context:
> > https://bugs.webkit.org/attachment.cgi?id=352115&action=review
> > 
> > > Source/WTF/wtf/StackBounds.cpp:55
> > > +    volatile uint8_t* stackValue = bitwise_cast<uint8_t*>(currentStackPointer());
> > 
> > Does this work on debug builds where this is an actual function call?
> 
> Yeah, at least in x64, it works :)

Yes, currentStackPointer() is designed to work on both release and debug builds.  They work differently though: the release build version relies on it being inlined, while the debug build version relies on it not being inlined.