On Sun, 13 Feb 2011, commits at source.squeak.org wrote:

> Nicolas Cellier uploaded a new version of Compiler to project The Trunk:
> http://source.squeak.org/trunk/Compiler-nice.188.mcz

Seems like you were a bit faster than me. I pushed my version to the 
Inbox, because if you recompile methods which send #repeat, then the 
DecompilerTests will fail with an error.


Levente

>
> ==================== Summary ====================
>
> Name: Compiler-nice.188
> Author: nice
> Time: 13 February 2011, 7:39:55.07 pm
> UUID: 66ccdff2-05b9-4294-9b3b-0bf2d84417fd
> Ancestors: Compiler-nice.187, Compiler-fbs.183, Compiler-nice.186
>
> Merge fbs.183 nice.186 nice.187 coming from inbox
>
> =============== Diff against Compiler-nice.187 ===============
>
> Item was changed:
>  InstructionStream subclass: #Decompiler
> + 	instanceVariableNames: 'constructor method instVars tempVars constTable stack statements lastPc exit caseExits lastJumpPc lastReturnPc limit hasValue blockStackBase numLocalTemps blockStartsToTempVars tempVarCount lastJumpIfPcStack'
> - 	instanceVariableNames: 'constructor method instVars tempVars constTable stack statements lastPc exit caseExits lastJumpPc lastReturnPc limit hasValue blockStackBase numLocalTemps blockStartsToTempVars tempVarCount'
>  	classVariableNames: 'ArgumentFlag CascadeFlag CaseFlag IfNilFlag'
>  	poolDictionaries: ''
>  	category: 'Compiler-Kernel'!
>
> + !Decompiler commentStamp: 'nice 2/3/2011 22:54' prior: 0!
> - !Decompiler commentStamp: 'nice 3/1/2010 19:56' prior: 0!
>  I decompile a method in three phases:
>  	Reverser: postfix byte codes -> prefix symbolic codes (nodes and atoms)
>  	Parser: prefix symbolic codes -> node tree (same as the compiler)
>  	Printer: node tree -> text (done by the nodes)
>
>
>  instance vars:
>
>  	constructor <DecompilerConstructor> an auxiliary knowing how to generate Abstract Syntax Tree (node tree)
>  	method <CompiledMethod> the method being decompiled
>  	instVars <Array of: String> the instance variables of the class implementing method
>  	tempVars <String | (OrderedCollection of: String)> hold the names of temporary variables (if known)
>  		NOTE: POLYMORPHISM WILL BE RESOLVED IN #initSymbols:
>  	constTable <Collection of: ParseNode> parse node associated with byte encoded constants (nil true false 0 1 -1 etc...)
>  	stack <OrderedCollection of: (ParseNode | String | Integer) > multipurpose...
>  	statements <OrderedCollection of: ParseNode> the statements of the method being decompiled
>  	lastPc <Integer>
>  	exit <Integer>
>  	caseExits <OrderedCollection of: Integer> - stack of exit addresses that have been seen in the branches of caseOf:'s
>  	lastJumpPc <Integer>
>  	lastReturnPc <Integer>
>  	limit <Integer>
>  	hasValue <Boolean>
>  	blockStackBase <Integer>
>  	numLocaltemps <Integer | Symbol> - number of temps local to a block; also a flag indicating decompiling a block
>  	blockStartsToTempVars <Dictionary key: Integer value: (OrderedCollection of: String)>
> + 	tempVarCount <Integer> number of temp vars used by the method
> + 	lastJumpIfPcStack <OrderedCollection of: Integer> the value of program counter just before the last encountered conditional jumps!
> - 	tempVarCount <Integer> number of temp vars used by the method!
>
> Item was changed:
>  ----- Method: Decompiler>>decompile:in:method:using: (in category 'public access') -----
>  decompile: aSelector in: aClass method: aMethod using: aConstructor
>
>  	| block node |
>  	constructor := aConstructor.
>  	method := aMethod.
>  	self initSymbols: aClass.  "create symbol tables"
>  	method isQuick
>  		ifTrue: [block := self quickMethod]
>  		ifFalse:
>  			[stack := OrderedCollection new: method frameSize.
> + 			lastJumpIfPcStack := OrderedCollection new.
>  			caseExits := OrderedCollection new.
>  			statements := OrderedCollection new: 20.
>  			numLocalTemps := 0.
>  			super method: method pc: method initialPC.
>  			"skip primitive error code store if necessary"
>  			(method primitive ~= 0 and: [self willStore]) ifTrue:
>  				[pc := pc + 2.
>  				 tempVars := tempVars asOrderedCollection].
>  			block := self blockTo: method endPC + 1.
>  			stack isEmpty ifFalse: [self error: 'stack not empty']].
>  	node := constructor
>  				codeMethod: aSelector
>  				block: block
>  				tempVars: tempVars
>  				primitive: method primitive
>  				class: aClass.
>  	method primitive > 0 ifTrue:
>  		[node removeAndRenameLastTempIfErrorCode].
>  	^node preen!
>
> Item was changed:
>  ----- Method: Decompiler>>interpretNextInstructionFor: (in category 'private') -----
>  interpretNextInstructionFor: client
>
>  	| code varNames |
>
>  "Change false here will trace all state in Transcript."
>  true ifTrue: [^ super interpretNextInstructionFor: client].
>
>  	varNames := self class allInstVarNames.
>  	code := (self method at: pc) radix: 16.
>  	Transcript cr; cr; print: pc; space;
> + 		nextPutAll: '<' , code, '>'.
> - 		nextPutAll: '<' , (code copyFrom: 4 to: code size), '>'.
>  	8 to: varNames size do:
>  		[:i | i <= 10 ifTrue: [Transcript cr]
>  				ifFalse: [Transcript space; space].
>  		Transcript nextPutAll: (varNames at: i);
>  				nextPutAll: ': '; print: (self instVarAt: i)].
>  	Transcript endEntry.
>  	^ super interpretNextInstructionFor: client!
>
> Item was changed:
>  ----- Method: Decompiler>>jump: (in category 'instruction decoding') -----
>  jump: dist
> + 	| blockBody destPc nextPC |
> + 	destPc := pc + dist.
> + 	(lastJumpIfPcStack isEmpty or: [dist < 0 and: [destPc > lastJumpIfPcStack last]])
> + 		ifTrue:
> + 			["Rule: aBackward jump not crossing a Bfp/Btp must be a repeat"
> + 			nextPC := pc.
> + 			pc := destPc.
> + 			blockBody := self statementsTo: lastPc.
> + 			blockBody size timesRepeat: [statements removeLast].
> + 			pc := nextPC.
> + 			statements addLast:
> + 				(constructor
> + 					codeMessage: (constructor codeBlock: blockBody returns: false)
> + 					selector: (constructor
> + 								codeSelector: #repeat
> + 								code: #macro)
> + 					arguments: #()).
> + 			]
> + 		ifFalse:
> + 			[exit := destPc.
> + 			lastJumpPc := lastPc]!
> -
> - 	exit := pc + dist.
> - 	lastJumpPc := lastPc!
>
> Item was changed:
>  ----- Method: Decompiler>>jump:if: (in category 'instruction decoding') -----
>  jump: dist if: condition
>
>  	| savePc sign elsePc elseStart end cond ifExpr thenBlock elseBlock
>  	  thenJump elseJump condHasValue isIfNil saveStack blockBody |
> + 	lastJumpIfPcStack addLast: lastPc.
> + 	stack last == CascadeFlag ifTrue: [^ [self case: dist] ensure: [lastJumpIfPcStack removeLast]].
> - 	stack last == CascadeFlag ifTrue: [^ self case: dist].
>  	elsePc := lastPc.
>  	elseStart := pc + dist.
>  	end := limit.
>  	"Check for bfp-jmp to invert condition.
>  	Don't be fooled by a loop with a null body."
>  	sign := condition.
>  	savePc := pc.
>  	self interpretJump ifNotNil:
>  		[:elseDist|
>  		 (elseDist >= 0 and: [elseStart = pc]) ifTrue:
>  			 [sign := sign not.  elseStart := pc + elseDist]].
>  	pc := savePc.
>  	ifExpr := stack removeLast.
>  	(isIfNil := stack size > 0 and: [stack last == IfNilFlag]) ifTrue:
>  		[stack removeLast].
>  	saveStack := stack.
>  	stack := OrderedCollection new.
>  	thenBlock := self blockTo: elseStart.
>  	condHasValue := hasValue or: [isIfNil].
>  	"ensure jump is within block (in case thenExpr returns)"
>  	thenJump := exit <= end ifTrue: [exit] ifFalse: [elseStart].
>  	"if jump goes back, then it's a loop"
>  	thenJump < elseStart
>  		ifTrue:
>  			["Must be a while loop...
>  			  thenJump will jump to the beginning of the while expr.  In the case of while's
>  			  with a block in the condition, the while expr should include more than just
>  			  the last expression: find all the statements needed by re-decompiling."
>  			stack := saveStack.
>  			pc := thenJump.
>  			blockBody := self statementsTo: elsePc.
>  			"discard unwanted statements from block"
>  			blockBody size - 1 timesRepeat: [statements removeLast].
>  			statements addLast:
>  				(constructor
>  					codeMessage: (constructor codeBlock: blockBody returns: false)
>  					selector: (constructor
>  								codeSelector: (sign
>  												ifTrue: [#whileFalse:]
>  												ifFalse: [#whileTrue:])
>  								code: #macro)
>  					arguments: { thenBlock }).
>  			pc := elseStart.
>  			self convertToDoLoop]
>  		ifFalse:
>  			["Must be a conditional..."
>  			elseBlock := self blockTo: thenJump.
>  			elseJump := exit.
>  			"if elseJump is backwards, it is not part of the elseExpr"
>  			elseJump < elsePc ifTrue:
>  				[pc := lastPc].
>  			cond := isIfNil
>  						ifTrue:
>  							[constructor
>  								codeMessage: ifExpr ifNilReceiver
>  								selector: (constructor
>  											codeSelector: (sign ifTrue: [#ifNotNil:] ifFalse: [#ifNil:])
>  											code: #macro)
>  								arguments: (Array with: thenBlock)]
>  						ifFalse:
>  							[constructor
>  								codeMessage: ifExpr
>  								selector: (constructor codeSelector: #ifTrue:ifFalse: code: #macro)
>  								arguments:	(sign
>  												ifTrue: [{elseBlock. thenBlock}]
>  												ifFalse: [{thenBlock. elseBlock}])].
>  			stack := saveStack.
>  			condHasValue
>  				ifTrue: [stack addLast: cond]
> + 				ifFalse: [statements addLast: cond]].
> + 	lastJumpIfPcStack removeLast.!
> - 				ifFalse: [statements addLast: cond]]!
>
> Item was changed:
>  ----- Method: MessageNode class>>initialize (in category 'class initialization') -----
> + initialize
> + 	"MessageNode initialize"
> - initialize		"MessageNode initialize"
>  	MacroSelectors :=
>  		#(	ifTrue: ifFalse: ifTrue:ifFalse: ifFalse:ifTrue:
>  			and: or:
>  			whileFalse: whileTrue: whileFalse whileTrue
>  			to:do: to:by:do:
>  			caseOf: caseOf:otherwise:
> + 			ifNil: ifNotNil:  ifNil:ifNotNil: ifNotNil:ifNil:
> + 			repeat ).
> - 			ifNil: ifNotNil:  ifNil:ifNotNil: ifNotNil:ifNil:).
>  	MacroTransformers :=
>  		#(	transformIfTrue: transformIfFalse: transformIfTrueIfFalse: transformIfFalseIfTrue:
>  			transformAnd: transformOr:
>  			transformWhile: transformWhile: transformWhile: transformWhile:
>  			transformToDo: transformToDo:
>  			transformCase: transformCase:
> + 			transformIfNil: transformIfNil:  transformIfNilIfNotNil: transformIfNotNilIfNil:
> + 			transformRepeat: ).
> - 			transformIfNil: transformIfNil:  transformIfNilIfNotNil: transformIfNotNilIfNil:).
>  	MacroEmitters :=
>  		#(	emitCodeForIf:encoder:value: emitCodeForIf:encoder:value:
>  			emitCodeForIf:encoder:value: emitCodeForIf:encoder:value:
>  			emitCodeForIf:encoder:value: emitCodeForIf:encoder:value:
>  			emitCodeForWhile:encoder:value: emitCodeForWhile:encoder:value:
>  			emitCodeForWhile:encoder:value: emitCodeForWhile:encoder:value:
>  			emitCodeForToDo:encoder:value: emitCodeForToDo:encoder:value:
>  			emitCodeForCase:encoder:value: emitCodeForCase:encoder:value:
>  			emitCodeForIfNil:encoder:value: emitCodeForIfNil:encoder:value:
> + 			emitCodeForIf:encoder:value: emitCodeForIf:encoder:value:
> + 			emitCodeForRepeat:encoder:value:).
> - 			emitCodeForIf:encoder:value: emitCodeForIf:encoder:value:).
>  	MacroSizers :=
>  		#(	sizeCodeForIf:value: sizeCodeForIf:value: sizeCodeForIf:value: sizeCodeForIf:value:
>  			sizeCodeForIf:value: sizeCodeForIf:value:
>  			sizeCodeForWhile:value: sizeCodeForWhile:value: sizeCodeForWhile:value: sizeCodeForWhile:value:
>  			sizeCodeForToDo:value: sizeCodeForToDo:value:
>  			sizeCodeForCase:value: sizeCodeForCase:value:
> + 			sizeCodeForIfNil:value: sizeCodeForIfNil:value: sizeCodeForIf:value: sizeCodeForIf:value:
> + 			sizeCodeForRepeat:value:).
> - 			sizeCodeForIfNil:value: sizeCodeForIfNil:value: sizeCodeForIf:value: sizeCodeForIf:value:).
>  	MacroPrinters :=
>  		#(	printIfOn:indent: printIfOn:indent: printIfOn:indent: printIfOn:indent:
>  			printIfOn:indent: printIfOn:indent:
>  			printWhileOn:indent: printWhileOn:indent: printWhileOn:indent: printWhileOn:indent:
>  			printToDoOn:indent: printToDoOn:indent:
>  			printCaseOn:indent: printCaseOn:indent:
> + 			printIfNil:indent: printIfNil:indent: printIfNilNotNil:indent: printIfNilNotNil:indent:
> + 			printRepeatOn:indent:)!
> - 			printIfNil:indent: printIfNil:indent: printIfNilNotNil:indent: printIfNilNotNil:indent:)!
>
> Item was added:
> + ----- Method: MessageNode>>emitCodeForRepeat:encoder:value: (in category 'code generation') -----
> + emitCodeForRepeat: stack encoder: encoder value: forValue
> + 	" L1: ... Jmp(L1)"
> + 	| loopSize |
> + 	loopSize := sizes at: 1.
> + 	receiver emitCodeForEvaluatedEffect: stack encoder: encoder.
> + 	self emitCodeForJump: 0 - loopSize encoder: encoder.
> + 	forValue ifTrue: [encoder genPushSpecialLiteral: nil. stack push: 1]!
>
> Item was added:
> + ----- Method: MessageNode>>printRepeatOn:indent: (in category 'printing') -----
> + printRepeatOn: aStream indent: level
> +
> + 	self printReceiver: receiver on: aStream indent: level.
> +
> + 	^self printKeywords: selector key
> + 		arguments: (Array new)
> + 		on: aStream indent: level!
>
> Item was added:
> + ----- Method: MessageNode>>sizeCodeForRepeat:value: (in category 'code generation') -----
> + sizeCodeForRepeat: encoder value: forValue
> + 	"L1: ... Jmp(L1) nil (nil for value only);"
> + 	| loopSize |
> + 	loopSize := (receiver sizeCodeForEvaluatedEffect: encoder) + (encoder sizeJumpLong: 1).
> + 	sizes := Array with: loopSize.
> + 	^loopSize + (forValue ifTrue: [encoder sizePushSpecialLiteral: nil] ifFalse: [0])!
>
> Item was added:
> + ----- Method: MessageNode>>transformRepeat: (in category 'macro transformations') -----
> + transformRepeat: encoder
> + 	"answer true if this #repeat message can be optimized"
> +
> + 	^(self checkBlock: receiver as: 'receiver' from: encoder)
> + 	   and: [receiver noteOptimizedIn: self.
> + 			true]!
>
> Item was removed:
> - ----- Method: VariableNode>>canBeSpecialArgument (in category 'testing') -----
> - canBeSpecialArgument
> - 	"Can I be an argument of (e.g.) ifTrue:?"
> -
> - 	^code < LdNil!
>
>
>