[Webkit-unassigned] [Bug 25246] New: Jumps may fail to be linked correctly on x86_64.

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=25246

           Summary: Jumps may fail to be linked correctly on x86_64.
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: Macintosh
        OS/Version: Mac OS X 10.5
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: barraclough at apple.com


A problem could occur where two pieces of JIT code which we intend to link
together fall more than 2Gb apart.  The solution here is to allocate a single
2gb region of VM from which all JIT code will be allocated.

This places an artificial 2Gb cap on JIT code.  If we wish to do so in future
we will need make it possible for the JIT to handle linking jumps between JIT
code regions further than 2Gb apart (we currently just assert that we don't hit
this case) – however even if we do so, it will likely still make sense to
allocate out of (multiple instances of) the heap implemented here (to ensure
the maximum amount of code possible is allocated within range of x86_64
relative branches).


-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.