[Vm-dev] VM Maker: VMMaker.oscog-eem.154.mcz

commits at source.squeak.org commits at source.squeak.org
Tue Apr 3 20:44:24 UTC 2012

Eliot Miranda uploaded a new version of VMMaker to project VM Maker:

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

Name: VMMaker.oscog-eem.154
Author: eem
Time: 3 April 2012, 1:42:00.802 pm
UUID: 5cbb57c7-0a54-4b7e-848c-1f292759f1fa
Ancestors: VMMaker.oscog-eem.153

Fix bad conceptual bug with become on methods.  Unlike full and
incremental GC, the reference from a Cog method to its method
object must not be remapped since they're two halves of the same

=============== Diff against VMMaker.oscog-eem.153 ===============

Item was changed:
  ----- Method: Cogit>>mapObjectReferencesInMachineCodeForBecome (in category 'garbage collection') -----
  	"Update all references to objects in machine code for a become.
+ 	 Unlike incrementalGC or fullGC a method that does not refer to young may
+ 	 refer to young as a result of the become operation.  Unlike incrementalGC
+ 	 or fullGC the reference from a Cog method to its methodObject *must not*
+ 	 change since the two are two halves of the same object."
- 	 Unlike incrementalGC or fullGC a method that does not refer to young
- 	 may refer to young as a result of the become operation."
  	| cogMethod hasYoungObj hasYoungObjPtr freedPIC |
  	<var: #cogMethod type: #'CogMethod *'>
  	hasYoungObj := false.
  	hasYoungObjPtr := self cCode: [(self addressOf: hasYoungObj) asInteger]
  							inSmalltalk: [CPluggableAccessor new
  											setObject: nil;
  											atBlock: [:obj :idx| hasYoungObj]
  											atPutBlock: [:obj :idx :val| hasYoungObj := val]].
  	codeModified := freedPIC := false.
  	self mapObjectReferencesInGeneratedRuntime.
  	cogMethod := self cCoerceSimple: methodZoneBase to: #'CogMethod *'.
  	[cogMethod < methodZone limitZony] whileTrue:
  		[self assert: hasYoungObj not.
  		 cogMethod cmType ~= CMFree ifTrue:
  			[self assert: (self cogMethodDoesntLookKosher: cogMethod) = 0.
  			 cogMethod selector: (objectRepresentation remapOop: cogMethod selector)..
  			 cogMethod cmType = CMClosedPIC
  					[((objectMemory isYoung: cogMethod selector)
  					   or: [self mapObjectReferencesInClosedPIC: cogMethod]) ifTrue:
  						[freedPIC := true.
  						 methodZone freeMethod: cogMethod]]
  					[(objectMemory isYoung: cogMethod selector) ifTrue:
  						[hasYoungObj := true].
  					 cogMethod cmType = CMMethod ifTrue:
  						[self assert: cogMethod objectHeader = objectMemory nullHeaderForMachineCodeMethod.
- 						 cogMethod methodObject: (objectRepresentation remapOop: cogMethod methodObject).
  						 self assert: ((coInterpreter rawHeaderOf: cogMethod methodObject) = cogMethod asInteger
  									or: [(self noAssertMethodClassAssociationOf: cogMethod methodObject)
  											= objectMemory nilObject]).
  						 (objectMemory isYoung: cogMethod methodObject) ifTrue:
  							[hasYoungObj := true]].
  					 self mapFor: cogMethod
  						 performUntil: (self cppIf: NewspeakVM
  											ifTrue: [#remapNSIfObjectRef:pc:hasYoung: asSymbol]
  											ifFalse: [#remapIfObjectRef:pc:hasYoung: asSymbol])
  						 arg: hasYoungObjPtr.
  							[cogMethod cmRefersToYoung ifFalse:
  								[cogMethod cmRefersToYoung: true.
  								 methodZone addToYoungReferrers: cogMethod].
  							hasYoungObj := false]
  						ifFalse: [cogMethod cmRefersToYoung: false]]].
  		cogMethod := methodZone methodAfter: cogMethod].
  	methodZone pruneYoungReferrers.
  	freedPIC ifTrue:
  		[self unlinkSendsToFree.
  		 codeModified := true].
  	codeModified ifTrue: "After updating oops in inline caches we need to flush the icache."
  		[processor flushICacheFrom: codeBase to: methodZone limitZony asInteger]!

More information about the Vm-dev mailing list