[Vm-dev] VM Maker: VMMaker.oscog-cb.1908.mcz

[commits at source.squeak.org]

ClementBera uploaded a new version of VMMaker to project VM Maker:
http://source.squeak.org/VMMaker/VMMaker.oscog-cb.1908.mcz

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

Name: VMMaker.oscog-cb.1908
Author: cb
Time: 25 July 2016, 2:04:51.652914 pm
UUID: e6026e8d-6049-4d45-bc26-ed2d9efda4e9
Ancestors: VMMaker.oscog-cb.1907

fixed minor bug in noMustBeBoolean flag and added a comment.

=============== Diff against VMMaker.oscog-cb.1907 ===============

Item was changed:
  ----- Method: SistaCogit>>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>
  	| ok counterAddress countTripped retry nextPC nextDescriptor |
  	<var: #ok type: #'AbstractInstruction *'>
  	<var: #retry type: #'AbstractInstruction *'>
  	<var: #countTripped type: #'AbstractInstruction *'>
  	<var: #nextDescriptor type: #'BytecodeDescriptor *'>
  
  	(coInterpreter isOptimizedMethod: methodObj) ifTrue: [ ^ super genJumpIf: boolean to: targetBytecodePC ].
  	
  	branchReachedOnlyForCounterTrip ifTrue: 
  		[ branchReachedOnlyForCounterTrip := false.
  		^ self genCounterTripOnlyJumpIf: boolean to: targetBytecodePC ].
  	
  	boolean == objectMemory falseObject ifTrue:
  		[ "detection of and: / or:"
  		nextPC := bytecodePC + (self generatorAt: byte0) numBytes.
  		nextDescriptor := self generatorAt: (objectMemory fetchByte: nextPC ofObject: methodObj) + bytecodeSetOffset.
  		nextDescriptor generator ==  #genPushConstantTrueBytecode ifTrue: [ ^ super genJumpIf: boolean to: targetBytecodePC ].
  		nextDescriptor := self generatorAt: (objectMemory fetchByte: targetBytecodePC ofObject: methodObj) + bytecodeSetOffset.
  		nextDescriptor generator ==  #genPushConstantFalseBytecode ifTrue: [ ^ super genJumpIf: boolean to: targetBytecodePC ].  ].
  
+ 	extA := 0. "ignore the noMustBeBoolean flag - should not be present in methods with counters"
- 	extA := 0.
  
  	self ssFlushTo: simStackPtr - 1.
  	self ssTop popToReg: TempReg.
  	self ssPop: 1.
  
  	"We need SendNumArgsReg because of the mustBeBooleanTrampoline"
  	self ssAllocateRequiredReg: SendNumArgsReg.
  
  	retry := self Label.
  	self 
  		genExecutionCountLogicInto: [ :cAddress :countTripBranch | 
  			counterAddress := cAddress. 
  			countTripped := countTripBranch ] 
  		counterReg: SendNumArgsReg.
  	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 genSubConstant: boolean R: TempReg.
  	self JumpZero: (self ensureFixupAt: targetBytecodePC - initialPC).
  
  	self genFallsThroughCountLogicCounterReg: SendNumArgsReg 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."
  	
  	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.
  	^0!

Item was changed:
  ----- Method: StackToRegisterMappingCogit>>genJumpIf:to: (in category 'bytecode generator support') -----
  genJumpIf: boolean to: targetBytecodePC
  	<inline: false>
  	| desc fixup ok |
  	<var: #desc type: #'CogSimStackEntry *'>
  	<var: #fixup type: #'BytecodeFixup *'>
  	<var: #ok type: #'AbstractInstruction *'>
  	self ssFlushTo: simStackPtr - 1.
  	desc := self ssTop.
  	self ssPop: 1.
  	(desc type == SSConstant
  	 and: [desc constant = objectMemory trueObject or: [desc constant = objectMemory falseObject]]) ifTrue:
  		["Must arrange there's a fixup at the target whether it is jumped to or
  		  not so that the simStackPtr can be kept correct."
  		 fixup := self ensureFixupAt: targetBytecodePC - initialPC.
  		 "Must annotate the bytecode for correct pc mapping."
  		 self annotateBytecode: (desc constant = boolean
  									ifTrue: [self Jump: fixup]
  									ifFalse: [self prevInstIsPCAnnotated
  												ifTrue: [self Nop]
  												ifFalse: [self Label]]).
+ 		 extA := 0.
  		 ^0].
  	desc popToReg: TempReg.
  	"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 genSubConstant: boolean R: TempReg.
  	self JumpZero: (self ensureFixupAt: targetBytecodePC - initialPC).
  	
  	self extASpecifiesNoMustBeBoolean ifTrue: 
  		[ extA := 0. 
  		self annotateBytecode: self lastOpcode.
  		^ 0].
  	extA := 0.
  	
  .	self CmpCq: (boolean == objectMemory falseObject
  					ifTrue: [objectMemory trueObject - objectMemory falseObject]
  					ifFalse: [objectMemory falseObject - objectMemory trueObject])
  		R: TempReg.
  	ok := self JumpZero: 0.
  	self CallRT: (boolean == objectMemory falseObject
  					ifTrue: [ceSendMustBeBooleanAddFalseTrampoline]
  					ifFalse: [ceSendMustBeBooleanAddTrueTrampoline]).
  	ok jmpTarget: (self annotateBytecode: self Label).
  	^0!