https://bugs.webkit.org/show_bug.cgi?id=126555

Reviewed by Geoffrey Garen.

This patch adds support for copying to our generational collector. Eden collections 
always trigger copying. Full collections use our normal fragmentation-based heuristics.

The way this works is that the CopiedSpace now has the notion of an old generation set of CopiedBlocks
and a new generation of CopiedBlocks. During each mutator cycle new CopiedSpace allocations reside
in the new generation. When a collection occurs, those blocks are moved to the old generation.

One key thing to remember is that both new and old generation objects in the MarkedSpace can
refer to old or new generation allocations in CopiedSpace. This is why we must fire write barriers 
when assigning to an old (MarkedSpace) object's Butterfly.

* heap/CopiedAllocator.h:
(JSC::CopiedAllocator::tryAllocateDuringCopying):
* heap/CopiedBlock.h:
(JSC::CopiedBlock::CopiedBlock):
(JSC::CopiedBlock::didEvacuateBytes):
(JSC::CopiedBlock::isOld):
(JSC::CopiedBlock::didPromote):
* heap/CopiedBlockInlines.h:
(JSC::CopiedBlock::reportLiveBytes):
(JSC::CopiedBlock::reportLiveBytesDuringCopying):
* heap/CopiedSpace.cpp:
(JSC::CopiedSpace::CopiedSpace):
(JSC::CopiedSpace::~CopiedSpace):
(JSC::CopiedSpace::init):
(JSC::CopiedSpace::tryAllocateOversize):
(JSC::CopiedSpace::tryReallocateOversize):
(JSC::CopiedSpace::doneFillingBlock):
(JSC::CopiedSpace::didStartFullCollection):
(JSC::CopiedSpace::doneCopying):
(JSC::CopiedSpace::size):
(JSC::CopiedSpace::capacity):
(JSC::CopiedSpace::isPagedOut):
* heap/CopiedSpace.h:
(JSC::CopiedSpace::CopiedGeneration::CopiedGeneration):
* heap/CopiedSpaceInlines.h:
(JSC::CopiedSpace::contains):
(JSC::CopiedSpace::recycleEvacuatedBlock):
(JSC::CopiedSpace::allocateBlock):
(JSC::CopiedSpace::startedCopying):
* heap/CopyVisitor.cpp:
(JSC::CopyVisitor::copyFromShared):
* heap/CopyVisitorInlines.h:
(JSC::CopyVisitor::allocateNewSpace):
(JSC::CopyVisitor::allocateNewSpaceSlow):
* heap/GCThreadSharedData.cpp:
(JSC::GCThreadSharedData::didStartCopying):
* heap/Heap.cpp:
(JSC::Heap::copyBackingStores):
* heap/SlotVisitorInlines.h:
(JSC::SlotVisitor::copyLater):
* heap/TinyBloomFilter.h:
(JSC::TinyBloomFilter::add):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162017 268f45cc-cd09-0410-ab3c-d52691b4dbfc