Bug 190503

Summary:

Use currentStackPointer more

Product:

WebKit

Reporter:

Yusuke Suzuki <ysuzuki>

Component:

New Bugs

Assignee:

Yusuke Suzuki <ysuzuki>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

benjamin, cdumez, cmarcelo, dbates, ews-watchlist, keith_miller, mark.lam, msaboff, saam, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Patch	saam: review+

Description Yusuke Suzuki 2018-10-11 18:03:44 PDT

Use currentStackPointer more

Comment 1 Yusuke Suzuki 2018-10-11 18:04:24 PDT

Created attachment 352115 [details]
Patch

Comment 2 Saam Barati 2018-10-11 18:19:03 PDT

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?

Comment 3 Yusuke Suzuki 2018-10-11 18:31:58 PDT

(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 :)

Comment 4 Yusuke Suzuki 2018-10-11 18:33:40 PDT

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

Comment 5 Radar WebKit Bug Importer 2018-10-11 18:34:26 PDT

<rdar://problem/45213815>

Comment 6 Mark Lam 2018-10-11 18:50:53 PDT

(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.