https://bugs.webkit.org/show_bug.cgi?id=99222

Reviewed by Filip Pizlo.

Right now CopiedSpace and MarkedSpace have the same block size and share the same regions,
but there's no reason that they can't have different block sizes while still sharing the
same underlying regions. We should factor the two "used" lists of regions apart so that
MarkedBlocks and CopiedBlocks can be different sizes. Regions will still be a uniform size
so that when they become empty they may be shared between the CopiedSpace and the MarkedSpace,
since benchmarks indicate that sharing is a boon for performance.

* heap/BlockAllocator.cpp:
(JSC::BlockAllocator::BlockAllocator):
* heap/BlockAllocator.h:
(JSC):
(Region):
(JSC::Region::create): We now have a fixed size for Regions so that empty regions can continue to
be shared between the MarkedSpace and CopiedSpace. Once they are used for a specific type of block,
however, they can only be used for that type of block until they become empty again.
(JSC::Region::createCustomSize):
(JSC::Region::Region):
(JSC::Region::~Region):
(JSC::Region::reset):
(BlockAllocator):
(JSC::BlockAllocator::RegionSet::RegionSet):
(RegionSet):
(JSC::BlockAllocator::tryAllocateFromRegion): We change this function so that it correctly
moves blocks between empty, partial, and full lists.
(JSC::BlockAllocator::allocate):
(JSC::BlockAllocator::allocateCustomSize):
(JSC::BlockAllocator::deallocate): Ditto.
(JSC::CopiedBlock):
(JSC::MarkedBlock):
(JSC::BlockAllocator::regionSetFor): We use this so that we can use the same allocate/deallocate
functions with different RegionSets. We specialize the function for each type of block that we
want to allocate.
* heap/CopiedBlock.h:
(CopiedBlock):
* heap/CopiedSpace.h:
(CopiedSpace):
* heap/HeapBlock.h:
(HeapBlock):
* heap/MarkedBlock.cpp:
(JSC::MarkedBlock::MarkedBlock): For oversize MarkedBlocks, if the block size gets too big we can
underflow the endAtom, which will cause us to segfault when we try to sweep a block. If we're a
custom size MarkedBlock we need to calculate endAtom so it doesn't underflow.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@131321 268f45cc-cd09-0410-ab3c-d52691b4dbfc