Eliot Miranda uploaded a new version of VMMaker to project VM Maker: http://source.squeak.org/VMMaker/VMMaker.oscog-eem.621.mcz
==================== Summary ====================
Name: VMMaker.oscog-eem.621 Author: eem Time: 24 February 2014, 2:23:42.1 pm UUID: 5b811028-86e2-4574-9163-5e47f4c7f3eb Ancestors: VMMaker.oscog-eem.620
Use followForward: when accessing the elements of the array(s) in become, since there's nothing that ensures uniqueness and/or disjointness in the elements. Hence explicitly filter-out an object becomming itself.
=============== Diff against VMMaker.oscog-eem.620 ===============
Item was changed: ----- Method: SpurMemoryManager>>innerBecomeObjectsIn:and:copyHash: (in category 'become implementation') ----- innerBecomeObjectsIn: array1 and: array2 copyHash: copyHashFlag "Inner loop of two-way become." 0 to: (self numSlotsOf: array1) - 1 do: [:i| | obj1 obj2 | + "At first blush it would appear unnecessary to use followField: here since + the validation in become:with:twoWay:copyHash: follows forwarders. But + there's nothing to ensure all elements of each array is unique and doesn't + appear in the other array. So the enumeration could encounter an object + already becommed earlier in the same enumeration." + obj1 := self followField: i ofObject: array1. + obj2 := self followField: i ofObject: array2. + obj1 ~= obj2 ifTrue: + [self doBecome: obj1 and: obj2 copyHash: copyHashFlag. + self followField: i ofObject: array1. + self followField: i ofObject: array2]]! - obj1 := self fetchPointer: i ofObject: array1. - obj2 := self fetchPointer: i ofObject: array2. - self doBecome: obj1 and: obj2 copyHash: copyHashFlag. - (self isForwarded: obj1) ifTrue: - [obj1 := self followForwarded: obj1. - self storePointer: i ofObject: array1 withValue: obj1]. - (self isForwarded: obj2) ifTrue: - [obj2 := self followForwarded: obj2. - self storePointer: i ofObject: array2 withValue: obj2]]!
Item was changed: ----- Method: SpurMemoryManager>>innerBecomeObjectsIn:to:copyHash: (in category 'become implementation') ----- innerBecomeObjectsIn: array1 to: array2 copyHash: copyHashFlag "Inner loop of one-way become." 0 to: (self numSlotsOf: array1) - 1 do: [:i| | obj1 obj2 | + "At first blush it would appear unnecessary to use followField: here since + the validation in become:with:twoWay:copyHash: follows forwarders. But + there's nothing to ensure all elements of each array is unique and doesn't + appear in the other array. So the enumeration could encounter an object + already becommed earlier in the same enumeration." + obj1 := self followField: i ofObject: array1. + obj2 := self followField: i ofObject: array2. + obj1 ~= obj2 ifTrue: + [self doBecome: obj1 to: obj2 copyHash: copyHashFlag. + self followField: i ofObject: array1. + self assert: (self isForwarded: obj2) not]]! - obj1 := self fetchPointer: i ofObject: array1. - obj2 := self fetchPointer: i ofObject: array2. - self doBecome: obj1 to: obj2 copyHash: copyHashFlag. - (self isForwarded: obj1) ifTrue: - [obj1 := self followForwarded: obj1. - self storePointer: i ofObject: array1 withValue: obj1]. - self assert: (self isForwarded: obj2) not]!