of an array.  The code now keeps a bias that indicates the amount of
JSValue sized holes are prior to the ArrayStorage block.  This means
that shift operations are now memmove's of the header part of
the ArrayStorage and unshift operations are similar, but may require a
realloc first to create the space.  Similar operations are performed
for special cases of splice and slice.
Also optimized the new Array(size) case so that we don't allocate and
initialize array elements until the JS code starts using elements.
The array growth code is slightly more aggressive for initial growth
based on size growth of any previous array.

Patch by Michael Saboff <msaboff@apple.com> on 2010-07-29
Reviewed by Gavin Barraclough.

* Configurations/JavaScriptCore.xcconfig:
* jit/JITPropertyAccess.cpp:
(JSC::JIT::emit_op_get_by_val):
(JSC::JIT::emit_op_put_by_val):
(JSC::JIT::privateCompilePatchGetArrayLength):
* jit/JITPropertyAccess32_64.cpp:
(JSC::JIT::emit_op_get_by_val):
(JSC::JIT::emit_op_put_by_val):
(JSC::JIT::privateCompilePatchGetArrayLength):
* runtime/ArrayPrototype.cpp:
(JSC::arrayProtoFuncShift):
(JSC::arrayProtoFuncSplice):
(JSC::arrayProtoFuncUnShift):
* runtime/JSArray.cpp:
(JSC::JSArray::JSArray):
(JSC::JSArray::~JSArray):
(JSC::JSArray::getOwnPropertySlot):
(JSC::JSArray::getOwnPropertyDescriptor):
(JSC::JSArray::put):
(JSC::JSArray::putSlowCase):
(JSC::JSArray::deleteProperty):
(JSC::JSArray::getOwnPropertyNames):
(JSC::JSArray::getNewVectorLength):
(JSC::JSArray::increaseVectorLength):
(JSC::JSArray::increaseVectorPrefixLength):
(JSC::JSArray::setLength):
(JSC::JSArray::pop):
(JSC::JSArray::push):
(JSC::JSArray::shiftCount):
(JSC::JSArray::unshiftCount):
(JSC::JSArray::sortNumeric):
(JSC::JSArray::sort):
(JSC::JSArray::fillArgList):
(JSC::JSArray::copyToRegisters):
(JSC::JSArray::compactForSorting):
(JSC::JSArray::subclassData):
(JSC::JSArray::setSubclassData):
(JSC::JSArray::checkConsistency):
* runtime/JSArray.h:
(JSC::JSArray::length):
(JSC::JSArray::canGetIndex):
(JSC::JSArray::getIndex):
(JSC::JSArray::setIndex):
(JSC::JSArray::uncheckedSetIndex):
(JSC::JSArray::arrayStorage):
(JSC::JSArray::setArrayStorage):
(JSC::JSArray::markChildrenDirect):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@64320 268f45cc-cd09-0410-ab3c-d52691b4dbfc