Bug 128226 – The stack limit computation does not work for Windows

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Mark Lam]

The current stack limit computation assumes that the stack is allocated in high memory.  On Windows, the stack seems to be allocated very near address 0, and is smaller in size than our Options::maxPerThreadStackUsage().  This combination triggers a bug where StackBounds::recursionLimit() underflows and computes a limit address that is ridiculously high in memory.  The net effect is that the Windows port thinks its out of stack space all the time.

Fix coming.

[Mark Lam]

Created attachment 223195 [details]
fixed StackBound::recursionLimit() to handle underflows.

[Oliver Hunt]

Comment on attachment 223195 [details]
fixed StackBound::recursionLimit() to handle underflows.

View in context: https://bugs.webkit.org/attachment.cgi?id=223195&action=review

> Source/JavaScriptCore/llint/LowLevelInterpreter.cpp:156
> +    CLoopRegister() { i = static_cast<intptr_t>(0xbadbeef0baddbeef); }

tasty, but won't this break in 32bit builds?

[Mark Lam]

Comment on attachment 223195 [details]
fixed StackBound::recursionLimit() to handle underflows.

View in context: https://bugs.webkit.org/attachment.cgi?id=223195&action=review

>> Source/JavaScriptCore/llint/LowLevelInterpreter.cpp:156
>> +    CLoopRegister() { i = static_cast<intptr_t>(0xbadbeef0baddbeef); }
> 
> tasty, but won't this break in 32bit builds?

Nope.  That's what the static_cast<intptr_t> takes care of for me.  I verified that the 32-bit build is happy.

[Mark Lam]

Created attachment 223198 [details]
I fixed the patch, but apparently uploaded the wrong one.  Round 2.

[Mark Lam]

Comment on attachment 223198 [details]
I fixed the patch, but apparently uploaded the wrong one.  Round 2.

A bad patch again.  Redoing.

[Mark Lam]

Created attachment 223200 [details]
Trying again.

[Mark Lam]

Patch 3 has passed the layout tests with a debug build.

[Geoffrey Garen]

Comment on attachment 223200 [details]
Trying again.

r=me

[WebKit Commit Bot]

Comment on attachment 223200 [details]
Trying again.

Clearing flags on attachment: 223200

Committed r163428: <http://trac.webkit.org/changeset/163428>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.