[Vm-dev] VM Maker: VMMaker.oscog-eem.607.mcz

[commits at source.squeak.org]

Eliot Miranda uploaded a new version of VMMaker to project VM Maker:
http://source.squeak.org/VMMaker/VMMaker.oscog-eem.607.mcz

==================== Summary ====================

Name: VMMaker.oscog-eem.607
Author: eem
Time: 4 February 2014, 3:40:08.328 pm
UUID: 9be0d8dc-ed68-4f51-becb-f83ed96185bf
Ancestors: VMMaker.oscog-eem.606

Following forwarders in Spur markAndTrace: requires a store check.

=============== Diff against VMMaker.oscog-eem.606 ===============

Item was changed:
  ----- Method: SpurMemoryManager>>markAndTrace: (in category 'gc - global') -----
  markAndTrace: objOop
  	"Mark the argument, and all objects reachable from it, and any remaining objects
  	 on the mark stack. Follow forwarding pointers in the scan."
  	<api>
  	| objToScan numStrongSlots index field |
  	(self markAndShouldScan: objOop) ifFalse:
  		[^self].
  	"if markAndTrace: is to follow and eliminate forwarding pointers
  	 in its scan it cannot be handed an r-value which is forwarded."
  	self assert: (self isForwarded: objOop) not.
  
  	"Now scan the object, and any remaining objects on the mark stack."
  	objToScan := objOop.
  	"To avoid overflowing the mark stack when we encounter large objects, we
  	 push the obj, then its numStrongSlots, and then index the object from the stack."
  	[((self isImmediate: objToScan)
  	  or: [numStrongSlots := self numStrongSlotsOf: objToScan ephemeronInactiveIf: #inactiveOrFailedToDeferScan:.
  		 numStrongSlots > self traceImmediatelySlotLimit])
  		ifTrue: "scanning a large object. scan until hitting an unmarked object, then switch to it, if any."
  			[(self isImmediate: objToScan)
  				ifTrue:
  					[index := self integerValueOf: objToScan.
  					 objToScan := self topOfObjStack: markStack]
  				ifFalse:
  					[index := numStrongSlots.
  					 self markAndTraceClassOf: objToScan].
  			 [index > 0] whileTrue:
  				[index := index - 1.
  				 field := self fetchPointer: index ofObject: objToScan.
  				 (self isOopForwarded: field) ifTrue:
  					[field := self followForwarded: field.
+ 					 self storePointer: index ofObject: objToScan withValue: field].
- 					 self storePointerUnchecked: index ofObject: objToScan withValue: field].
  				 (self markAndShouldScan: field) ifTrue:
  					[index > 0 ifTrue:
  						[(self topOfObjStack: markStack) ~= objToScan ifTrue: 
  							[self push: objToScan onObjStack: markStack].
  						 self push: (self integerObjectOf: index) onObjStack: markStack].
  					 objToScan := field.
  					 index := -1]].
  			 index >= 0 ifTrue: "if loop terminated without finding an unmarked referent, switch to top of stack."
  				[objToScan := self popObjStack: markStack.
  				 objToScan = objOop ifTrue:
  					[objToScan := self popObjStack: markStack]]]
  		ifFalse: "scanning a small object. scan, marking, pushing unmarked referents, then switch to the top of the stack."
  			[index := numStrongSlots.
  			 self markAndTraceClassOf: objToScan.
  			 [index > 0] whileTrue:
  				[index := index - 1.
  				 field := self fetchPointer: index ofObject: objToScan.
  				 (self isOopForwarded: field) ifTrue:
  					[field := self followForwarded: field.
+ 					 self storePointer: index ofObject: objToScan withValue: field].
- 					 self storePointerUnchecked: index ofObject: objToScan withValue: field].
  				 (self markAndShouldScan: field) ifTrue:
  					[self push: field onObjStack: markStack.
  					 numStrongSlots := self numStrongSlotsOf: field ephemeronInactiveIf: #inactiveOrFailedToDeferScan:.
  					 numStrongSlots > self traceImmediatelySlotLimit ifTrue:
  						[self push: (self integerObjectOf: numStrongSlots) onObjStack: markStack]]].
  			 objToScan := self popObjStack: markStack].
  	 objToScan notNil] whileTrue!