https://bugs.webkit.org/show_bug.cgi?id=96214

Originally reviewed by Oliver Hunt, then I added a design revision by
suggested by Phil Pizlo.

I expanded the imprecise size classes to cover up to 32KB, then added
an mmap-based allocator for everything bigger. There's a lot of tuning
we could do in these size classes, but currently they're almost
completely unused, so I haven't done any tuning.

Subtle point: the large allocator is a degenerate case of our free list
logic. Its list only ever contains zero or one items.

* heap/Heap.h:
(JSC::Heap::allocateStructure): Pipe in size information.

* heap/MarkedAllocator.cpp:
(JSC::MarkedAllocator::tryAllocateHelper): Handle the case where we
find a free item in the sweep list but the item isn't big enough. This
can happen in the large allocator because it mixes sizes.

(JSC::MarkedAllocator::tryAllocate):
(JSC::MarkedAllocator::allocateSlowCase): More piping.

(JSC::MarkedAllocator::allocateBlock): Handle the oversize case.

(JSC::MarkedAllocator::addBlock): I moved the call to didAddBlock here
because it made more sense.

* heap/MarkedAllocator.h:
(MarkedAllocator):
(JSC::MarkedAllocator::allocate):
* heap/MarkedSpace.cpp:
(JSC::MarkedSpace::MarkedSpace):
(JSC::MarkedSpace::resetAllocators):
(JSC::MarkedSpace::canonicalizeCellLivenessData):
(JSC::MarkedSpace::isPagedOut):
(JSC::MarkedSpace::freeBlock):
* heap/MarkedSpace.h:
(MarkedSpace):
(JSC::MarkedSpace::allocatorFor):
(JSC::MarkedSpace::destructorAllocatorFor):
(JSC::MarkedSpace::allocateWithoutDestructor):
(JSC::MarkedSpace::allocateWithDestructor):
(JSC::MarkedSpace::allocateStructure):
(JSC::MarkedSpace::forEachBlock):
* runtime/Structure.h:
(JSC::Structure): More piping.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@128141 268f45cc-cd09-0410-ab3c-d52691b4dbfc