[Vm-dev] VM Maker: VMMaker.oscog-cb.1283.mcz

commits at source.squeak.org commits at source.squeak.org
Tue May 5 09:49:58 UTC 2015

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

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

Name: VMMaker.oscog-cb.1283
Author: cb
Time: 5 May 2015, 11:48:13.804 am
UUID: 3000cd43-f84f-4b75-9fdf-aff579a5105b
Ancestors: VMMaker.oscog-eem.1282

Fixed a bug in SistaCogit where a trampoline needed a specific register instead of an allocated one.

=============== Diff against VMMaker.oscog-eem.1282 ===============

Item was removed:
- ----- Method: SistaStackToRegisterMappingCogit>>allocateRegPreferringCalleeSavedNotConflictingWith: (in category 'simulation stack') -----
- allocateRegPreferringCalleeSavedNotConflictingWith: regMask
- 	"If there are multiple free registers, choose one which is callee saved,
- 	else just allocate a register not conflicting with regMask"
- 	| reg |
- 	reg := backEnd availableRegisterOrNilFor: ((self liveRegisters bitOr: regMask) bitOr: callerSavedRegMask).
- 	^ reg
- 		ifNil: [ self allocateRegNotConflictingWith: regMask ]
- 		ifNotNil: [ reg ]!

Item was changed:
  ----- Method: SistaStackToRegisterMappingCogit>>genJumpIf:to: (in category 'bytecode generator support') -----
  genJumpIf: boolean to: targetBytecodePC
  	"The heart of performance counting in Sista.  Conditional branches are 6 times less
  	 frequent than sends and can provide basic block frequencies (send counters can't).
  	 Each conditional has a 32-bit counter split into an upper 16 bits counting executions
  	 and a lower half counting untaken executions of the branch.  Executing the branch
  	 decrements the upper half, tripping if the count goes negative.  Not taking the branch
  	 decrements the lower half.  N.B. We *do not* eliminate dead branches (true ifTrue:/true ifFalse:)
  	 so that scanning for send and branch data is simplified and that branch data is correct."
  	<inline: false>
+ 	| desc ok counterAddress countTripped retry |
- 	| desc ok counterAddress countTripped retry counterReg |
  	<var: #ok type: #'AbstractInstruction *'>
  	<var: #desc type: #'CogSimStackEntry *'>
  	<var: #retry type: #'AbstractInstruction *'>
  	<var: #countTripped type: #'AbstractInstruction *'>
  	(coInterpreter isOptimizedMethod: methodObj) ifTrue: [ ^ super genJumpIf: boolean to: targetBytecodePC ].
  	self ssFlushTo: simStackPtr - 1.
  	desc := self ssTop.
  	self ssPop: 1.
  	desc popToReg: TempReg.
+ 	"We need SendNumArgsReg because of the mustBeBooleanTrampoline"
+ 	self ssAllocateRequiredReg: SendNumArgsReg.
- 	"We prefer calleeSaved to avoid saving it across the trap trip trampoline"
- 	counterReg := self allocateRegPreferringCalleeSavedNotConflictingWith: 0. 
  	retry := self Label.
  		genExecutionCountLogicInto: [ :cAddress :countTripBranch | 
  			counterAddress := cAddress. 
  			countTripped := countTripBranch ] 
+ 		counterReg: SendNumArgsReg.
- 		counterReg: counterReg.
  	counterIndex := counterIndex + 1.
  	"Cunning trick by LPD.  If true and false are contiguous subtract the smaller.
  	 Correct result is either 0 or the distance between them.  If result is not 0 or
  	 their distance send mustBeBoolean."
  	self assert: (objectMemory objectAfter: objectMemory falseObject) = objectMemory trueObject.
  	self annotate: (self SubCw: boolean R: TempReg) objRef: boolean.
  	self JumpZero: (self ensureFixupAt: targetBytecodePC - initialPC).
+ 	self genFallsThroughCountLogicCounterReg: SendNumArgsReg counterAddress: counterAddress.
- 	self genFallsThroughCountLogicCounterReg: counterReg counterAddress: counterAddress.
  	self CmpCq: (boolean == objectMemory falseObject
  					ifTrue: [objectMemory trueObject - objectMemory falseObject]
  					ifFalse: [objectMemory falseObject - objectMemory trueObject])
  		R: TempReg.
  	ok := self JumpZero: 0.
+ 	self MoveCq: 0 R: SendNumArgsReg. "if counterReg is 0 this is a mustBeBoolean, not a counter trip."
- 	self MoveCq: 0 R: counterReg. "if counterReg is 0 this is a mustBeBoolean, not a counter trip."
  	countTripped jmpTarget:
  		(self CallRT: (boolean == objectMemory falseObject
  						ifTrue: [ceSendMustBeBooleanAddFalseTrampoline]
  						ifFalse: [ceSendMustBeBooleanAddTrueTrampoline])).
  	"If we're in an image which hasn't got the Sista code loaded then the ceCounterTripped:
  	 trampoline will return directly to machine code, returning the boolean.  So the code should
  	 jump back to the retry point. The trampoline makes sure that TempReg has been reloaded."
  	self annotateBytecode: self Label.
  	self Jump: retry.
  	ok jmpTarget: self Label.

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