Animation of the Lisp2 GC · STEP 2 computeAddresses(): for each visited array, compute a new...
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Animation of the Lisp2 GC (CGO Chapter 10)
Transcript of Animation of the Lisp2 GC · STEP 2 computeAddresses(): for each visited array, compute a new...
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Animation of the Lisp2 GC
(CGO Chapter 10)
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STEP 1
mark(addr): recursively mark all arrays that are reachable from the array beginning at address addr.
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mark(1)
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mark(1)
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mark(1)
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mark(1)
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mark(7)
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mark(7)
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mark(11)
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mark(11)
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mark(11)
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mark(11), done!
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Resume mark(7) after recursive call completes
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mark(7)
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mark(11), already visited
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mark(7), done!
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mark(1), done!
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STEP 2
computeAddresses(): for each visited array, compute a new address for the array in the compacted heap.
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computeAddresses()
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new = 1
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Set forwarding address
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new = 1
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new ← new + 3
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new = 4
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Advance scan pointer
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new = 4
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Advance scan pointer
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new = 4
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Set forwarding address
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new = 4
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new ← new + 4
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new = 8
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Advance scan pointer
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new = 8
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Set forwarding address
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new = 8
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new ← new + 3
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new = 11
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STEP 3
updatePointers(): update pointers to point to the forwarding addresses.
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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STEP 4
relocate(): relocate each array to its forwarding addresses.
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updatePointers()
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updatePointers()
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relocate to address 1
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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relocate to address 4
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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updatePointers()
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