Andreas Raab uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-ar.323.mcz

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

Name: Kernel-ar.323
Author: ar
Time: 4 December 2009, 6:32:01 am
UUID: 4b183b83-103d-a046-b240-8696b955d800
Ancestors: Kernel-ar.322

Faster #ensure: handling: Instead of having the default path use thisContext>>tempAt:put: (which is very slow for the JIT) use a temp assignment and let only the termination handling actually do #tempAt:put:.

Part 3 updates #ensure: to only use the fast version.

=============== Diff against Kernel-ar.322 ===============

Item was changed:
  ----- Method: BlockClosure>>ensure: (in category 'exceptions') -----
  ensure: aBlock
+ 	"Evaluate a termination block after evaluating the receiver, regardless of
+ 	 whether the receiver's evaluation completes.  N.B.  This method is *not*
+ 	 implemented as a primitive.  Primitive 198 always fails.  The VM uses prim
+ 	 198 in a context's method as the mark for an ensure:/ifCurtailed: activation."
- 	"Evaluate a termination block after evaluating the receiver, regardless of whether the receiver's evaluation completes."
  
+ 	| complete returnValue |
- 	| complete returnValue b |
  	<primitive: 198>
  	returnValue := self valueNoContextSwitch.
+ 	complete ifNil:[
- 	"aBlock wasn't nil when execution of this method began; it is nil'd out by the unwind machinery, and that's how we know it's already been evaluated ... otherwise, obviously, it needs to be evaluated"
- 	(aBlock == nil or:[complete == true]) ifFalse: [
- 		"nil out aBlock temp before evaluating aBlock so it is not executed again if aBlock remote returns"
- 		b := aBlock.
- 		thisContext tempAt: 1 put: nil.  "Could be aBlock := nil, but arguments cannot be modified"
  		complete := true.
+ 		aBlock value.
- 		b value.
  	].
  	^ returnValue!

Item was changed:
  ----- Method: BlockContext>>ensure: (in category 'exceptions') -----
  ensure: aBlock
+ 	"Evaluate a termination block after evaluating the receiver, regardless of
+ 	 whether the receiver's evaluation completes.  N.B.  This method is *not*
+ 	 implemented as a primitive.  Primitive 198 always fails.  The VM uses prim
+ 	 198 in a context's method as the mark for an ensure:/ifCurtailed: activation."
- 	"Evaluate a termination block after evaluating the receiver, regardless of whether the receiver's evaluation completes."
  
+ 	| complete returnValue |
- 	| complete returnValue b |
  	<primitive: 198>
  	returnValue := self value.
+ 	complete ifNil:[
- 	"aBlock wasn't nil when execution of this method began; it is nil'd out by the unwind machinery, and that's how we know it's already been evaluated ... otherwise, obviously, it needs to be evaluated"
- 	(aBlock == nil or:[complete == true]) ifFalse: [
- 		"nil out aBlock temp before evaluating aBlock so it is not executed again if aBlock remote returns"
- 		b := aBlock.
- 		thisContext tempAt: 1 put: nil.  "aBlock := nil"
  		complete := true.
+ 		aBlock value.
- 		b value.
  	].
  	^ returnValue!