"

 COPYRIGHT (c) 1989 by Claus Gittinger

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

ParseNode subclass:#MessageNode

       instanceVariableNames:'receiver selector argArray lineNr'

       classVariableNames:''

       poolDictionaries:''

       category:'System-Compiler-Support'

!

MessageNode comment:'

COPYRIGHT (c) 1989 by Claus Gittinger

              All Rights Reserved

'!

!MessageNode class methodsFor:'instance creation'!

receiver:recNode selector:selectorString 

    ^ (self basicNew) receiver:recNode selector:selectorString args:nil lineno:0

!

receiver:recNode selector:selectorString arg:argNode

    ^ self receiver:recNode selector:selectorString arg:argNode fold:true

!

receiver:recNode selector:selectorString arg:argNode fold:folding

    |result recVal argVal selector|

"

    The constant folding code can usually not optimize things - this may change

    when some kind of constant declaration is added to smalltalk.

"

    folding ifTrue:[

        "do constant folding ..."

        (recNode isConstant and:[argNode isConstant]) ifTrue:[

            "check if we can do it ..."

            selectorString knownAsSymbol ifTrue:[

                (recNode respondsTo:selectorString asSymbol) ifTrue:[

                    "we could do much more here - but then, we need a dependency from

                     the folded selectors method to the method we generate code for ...

                     limit optimizations to those that will never change

                     (or - if you change them - you will crash so bad ...)

                    "

                    selector := selectorString asSymbol.

                    recVal := recNode evaluate.

                    argVal := argNode evaluate.

                    (recVal respondsToArithmetic and:[argVal respondsToArithmetic]) ifTrue:[

                        (#( @ + - * / // \\ min: max:) includes:selector) ifTrue:[

                            (#( / // \\ ) includes:selector) ifTrue:[

                                argVal = 0 ifTrue:[

                                    ^ 'division by zero'

                                ].

                            ].

                            result := recVal perform:selector with:argVal.

                            ^ ConstantNode type:(ConstantNode typeOfConstant:result)

                                          value:result

                        ]

                    ].

                    (recVal isMemberOf:String) ifTrue:[

                        argVal respondsToArithmetic ifTrue:[

                            (selector == #at:) ifTrue:[

                                result := recVal perform:selector with:argVal.

                                ^ ConstantNode type:(ConstantNode typeOfConstant:result)

                                              value:result

                            ]

                        ].

                        (argVal isMemberOf:String) ifTrue:[

                            (selector == #',') ifTrue:[

                                result := recVal perform:selector with:argVal.

                                ^ ConstantNode type:(ConstantNode typeOfConstant:result)

                                              value:result

                            ]

                        ]

                    ]

                ]

            ]

        ]

    ].

    ^ (self basicNew) receiver:recNode selector:selectorString args:(Array with:argNode) lineno:0

!

receiver:recNode selector:selectorString args:anArray

    ^ self receiver:recNode selector:selectorString args:anArray fold:true

!

receiver:recNode selector:selectorString args:argArray fold:folding

    (argArray size == 1) ifTrue:[

        ^ self receiver:recNode selector:selectorString arg:(argArray at:1) fold:folding

    ].

    ^ (self basicNew) receiver:recNode selector:selectorString args:argArray lineno:0

! !

!MessageNode methodsFor:'accessing'!

receiver:r selector:s args:a lineno:l

    receiver := r.

    selector := s asSymbol.

    argArray := a.

    lineNr := l

!

receiver

    ^ receiver

!

selector

    ^ selector

!

args

    ^ argArray

!

arg1

    ^ argArray at:1

!

lineNumber

     ^ lineNr

!

lineNumber:num

     lineNr := num

! !

!MessageNode methodsFor:'queries'!

isMessage

    ^ true

! !

!MessageNode class methodsFor:'queries'!

hasLineNumber:sel

    "return true, if special send code needs lineNr"

    (sel == #==) ifTrue:[^ false].

    (sel == #~~) ifTrue:[^ false].

    (sel == #class) ifTrue:[^ false].

    ^ true

!

isBuiltInUnarySelector:sel

    "return true, if unary selector sel is built in"

    (sel == #peek) ifTrue:[^ true].

    (sel == #value) ifTrue:[^ true].

    (sel == #next) ifTrue:[^ true].

    (sel == #class) ifTrue:[^ true].

    (sel == #size) ifTrue:[^ true].

    (sel == #x) ifTrue:[^ true].

    (sel == #y) ifTrue:[^ true].

    (sel == #width) ifTrue:[^ true].

    (sel == #height) ifTrue:[^ true].

    (sel == #origin) ifTrue:[^ true].

    (sel == #extent) ifTrue:[^ true].

    (sel == #asInteger) ifTrue:[^ true].

    (sel == #rounded) ifTrue:[^ true].

    ^ false

!

isBuiltIn1ArgSelector:sel

    "return true, if selector sel is built in"

    (sel == #at:) ifTrue:[^ true].

    (sel == #value:) ifTrue:[^ true].

    (sel == #bitAnd:) ifTrue:[^ true].

    (sel == #bitOr:) ifTrue:[^ true].

    ^ false

!

isBuiltIn2ArgSelector:sel

    "return true, if selector sel is built in"

    (sel == #at:put:) ifTrue:[^ true].

    ^ false

! !

!MessageNode methodsFor:'printing'!

printOn:aStream indent:i

    |needParen selectorParts index index2 arg|

    (#(whileTrue: whileFalse:) includes:selector) ifTrue:[

        (receiver isKindOf:BlockNode) ifTrue:[

            ^ self printWhileOn:aStream indent:i

        ].

    ].

    index := 1.

    selectorParts := OrderedCollection new.

    [index == 0] whileFalse:[

        index2 := selector indexOf:$: startingAt:index.

        index2 ~~ 0 ifTrue:[

            selectorParts add:(selector copyFrom:index to:index2).

            index2 := index2 + 1

        ].

        index := index2

    ].

    needParen := false.

    receiver isMessage ifTrue:[

        receiver isUnaryMessage ifFalse:[

            receiver isBinaryMessage ifFalse:[

                needParen := true

            ].

        ].

    ].

    needParen ifTrue:[

        aStream nextPutAll:'('

    ].

    receiver printOn:aStream indent:i.

    needParen ifTrue:[

        aStream nextPutAll:')'

    ].

    1 to:(argArray size) do:[:argIndex |

        aStream space.

        (selectorParts at:argIndex) printOn:aStream.

        aStream space.

        arg := argArray at:argIndex.

        needParen := false.

        arg isMessage ifTrue:[

            arg isBinaryMessage ifFalse:[

                arg isUnaryMessage ifFalse:[

                    needParen := true

                ]

            ].

        ].

        needParen ifTrue:[

            aStream nextPutAll:'('

        ].

        arg printOn:aStream indent:i.

        needParen ifTrue:[

            aStream nextPutAll:') '

        ].

    ]

!

printWhileOn:aStream indent:i

    "special handling of whileTrue/whileFalse"

    aStream nextPutAll:'['.

    receiver statements printOn:aStream indent:i.

    aStream nextPutAll:'] whileTrue: '.

    arg := argArray at:1.

    needParen := false.

    arg isMessage ifTrue:[

        arg isBinaryMessage ifFalse:[

            arg isUnaryMessage ifFalse:[

                needParen := true

            ]

        ].

    ].

    needParen ifTrue:[

        aStream nextPutAll:'('

    ].

    arg printOn:aStream indent:i.

    needParen ifTrue:[

        aStream nextPutAll:') '

    ].

! !

!MessageNode methodsFor:'checks'!

plausibilityCheck

    |rec arg operand|

    "

     it once took me almost an hour, to find a '==' which

     should have been an '=' (you cannot compare floats with ==)

     (well, I saw it 50 times but didn't think about it ...).

     reason enough to add this check here.

    "

    ((selector == #==) or:[selector == #~~]) ifTrue:[

        receiver isConstant ifTrue:[

            rec := receiver evaluate.

            ((rec isMemberOf:String) or:[

             (rec isMemberOf:Float) or:[

             (rec isMemberOf:Fraction)]]) ifTrue:[

                operand := rec

            ].

        ].

        (argArray at:1) isConstant ifTrue:[

            arg := (argArray at:1) evaluate.

            ((arg isMemberOf:String) or:[

             (arg isMemberOf:Float) or:[

             (arg isMemberOf:Fraction)]]) ifTrue:[

                operand := arg

            ].

        ].

        operand notNil ifTrue:[

            (selector == #==) ifTrue:[

                ^ 'identity compare is unsafe here'

            ].

            ^ 'identity compare will usually return true here'

        ]

    ].

    "

     an error often occuring when you are a beginner ...

    "

    ((selector == #ifTrue:) or:[selector == #ifFalse:]) ifTrue:[

        receiver isBlock ifTrue:[

            (Block canUnderstand:selector) ifFalse:[

                ^ 'blocks usually do not respond to ' , selector , ' messages'

            ].

        ].

        (argArray at:1) isBlock ifFalse:[

            ^ 'will fail at runtime, if argument to ' , selector , ' does not evaluate to a block'

        ]

    ].

    ((selector == #ifTrue:ifFalse) or:[selector == #ifFalse:ifTrue]) ifTrue:[

        receiver isBlock ifTrue:[

            (Block canUnderstand:selector) ifFalse:[

                ^ 'blocks usually do not respond to ' , selector , ' messages'

            ].

        ].

        (argArray at:1) isBlock ifFalse:[

            ^ 'will fail at runtime, if 1st. argument to ' , selector , ' does not evaluate to a block'

        ].

        (argArray at:2) isBlock ifFalse:[

            ^ 'will fail at runtime, if 2nd. argument to ' , selector , ' does not evaluate to a block'

        ]

    ].

    ((selector == #whileTrue:) or:[selector == #whileFalse:]) ifTrue:[

        receiver isBlock ifFalse:[

            ^ 'will fail at runtime, if receiver of ' , selector , ' does not evaluate to a block'

        ].

        (argArray at:1) isBlock ifFalse:[

            ^ 'will fail at runtime, if argument to ' , selector , ' does not evaluate to a block'

        ].

    ].

    ^ nil

! !

!MessageNode methodsFor:'evaluating'!

evaluate

    |r nargs argValueArray index|

    argArray isNil ifTrue:[

        ^ (receiver evaluate) perform:selector

    ].

    nargs := argArray size.

    (nargs == 1) ifTrue:[

        ^ (receiver evaluate) perform:selector with:(argArray at:1) evaluate

    ].

    (nargs == 2) ifTrue:[

        ^ (receiver evaluate) perform:selector

                                 with:(argArray at:1) evaluate

                                 with:(argArray at:2) evaluate

    ].

    (nargs == 3) ifTrue:[

        ^ (receiver evaluate) perform:selector

                                 with:(argArray at:1) evaluate

                                 with:(argArray at:2) evaluate

                                 with:(argArray at:3) evaluate

    ].

    r := receiver evaluate.

    argValueArray := Array new:nargs.

    index := 1.

    [index <= nargs] whileTrue:[

        argValueArray at:index put:((argArray at:index) evaluate).

        index := index + 1

    ].

    ^ r perform:selector withArguments:argValueArray

!

evaluateForCascade

    |r nargs argValueArray index|

    r := receiver evaluate.

    argArray isNil ifTrue:[

        r perform:selector.

        ^ r

    ].

    nargs := argArray size.

    (nargs == 1) ifTrue:[

        r perform:selector with:(argArray at:1) evaluate.

        ^ r

    ].

    (nargs == 2) ifTrue:[

        r perform:selector with:(argArray at:1) evaluate

                           with:(argArray at:2) evaluate.

        ^ r

    ].

    (nargs == 3) ifTrue:[

        r perform:selector with:(argArray at:1) evaluate

                           with:(argArray at:2) evaluate

                           with:(argArray at:3) evaluate.

        ^ r

    ].

    argValueArray := Array new:nargs.

    index := 1.

    [index <= nargs] whileTrue:[

        argValueArray at:index put:((argArray at:index) evaluate).

        index := index + 1

    ].

    r perform:selector withArguments:argValueArray.

    ^ r

! !

!MessageNode methodsFor:'code generation'!

codeForSideEffectOn:aStream inBlock:b

    self codeOn:aStream inBlock:b valueNeeded:false

!

codeOn:aStream inBlock:b

    self codeOn:aStream inBlock:b valueNeeded:true

!

optimizedConditionFor:aReceiver with:aByteCode

    |rec sel|

    rec := aReceiver.

    (rec class == BlockNode) ifTrue:[

        rec statements nextStatement isNil ifTrue:[

            rec := rec statements expression

        ]

    ].

    (rec class == UnaryNode) ifTrue:[

        sel := rec selector.

        (sel == #isNil) ifTrue:[

            (aByteCode == #trueJump) ifTrue:[^ #nilJump].

            (aByteCode == #falseJump) ifTrue:[^ #notNilJump]

        ].

        (sel == #notNil) ifTrue:[

            (aByteCode == #trueJump) ifTrue:[^ #notNilJump].

            (aByteCode == #falseJump) ifTrue:[^ #nilJump]

        ].

        (sel == #not) ifTrue:[

            (aByteCode == #trueJump) ifTrue:[^ #falseJump].

            (aByteCode == #falseJump) ifTrue:[^ #trueJump]

        ].

        ^ nil

    ].

    (rec class == BinaryNode) ifTrue:[

        sel := rec selector.

        rec arg1 isConstant ifTrue:[

            (rec arg1 value == 0) ifTrue:[

                (sel == #==) ifTrue:[

                    (aByteCode == #trueJump) ifTrue:[^ #zeroJump].

                    (aByteCode == #falseJump) ifTrue:[^ #notZeroJump]

                ].

                (sel == #~~) ifTrue:[

                    (aByteCode == #falseJump) ifTrue:[^ #zeroJump].

                    (aByteCode == #trueJump) ifTrue:[^ #notZeroJump]

                ].

                ^ nil

            ]

        ].

        (sel == #==) ifTrue:[

            (aByteCode == #trueJump) ifTrue:[^ #eqJump].

            (aByteCode == #falseJump) ifTrue:[^ #notEqJump]

        ].

        (sel == #~~) ifTrue:[

            (aByteCode == #falseJump) ifTrue:[^ #eqJump].

            (aByteCode == #trueJump) ifTrue:[^ #notEqJump]

        ]

    ].

    ^ nil

!

codeWhileOn:aStream inBlock:b valueNeeded:valueNeeded

    "generate code for [...] whilexxx:[ ... ]"

    |pos pos2 theReceiver theArg theByteCode optByteCode|

    (selector == #whileTrue:) ifTrue:[

        theByteCode := #falseJump

    ] ifFalse:[

        theByteCode := #trueJump

    ].

    theReceiver := receiver.

    optByteCode := self optimizedConditionFor:theReceiver with:theByteCode.

    optByteCode notNil ifTrue:[

        ((optByteCode == #eqJump) or:[optByteCode == #notEqJump]) ifTrue:[

            theArg := receiver statements expression arg1

        ].

        theReceiver := receiver statements expression receiver.

        theByteCode := optByteCode

    ].

    valueNeeded ifTrue:[aStream nextPut:#pushNil].

    pos := aStream position.

    optByteCode notNil ifTrue:[

        theReceiver codeOn:aStream inBlock:b.

        theArg notNil ifTrue:[

            theArg codeOn:aStream inBlock:b

        ]

    ] ifFalse:[

        theReceiver codeInlineOn:aStream inBlock:b

    ].

    aStream nextPut:theByteCode.

    pos2 := aStream position.

    aStream nextPut:0.

    valueNeeded ifTrue:[aStream nextPut:#drop].

    (argArray at:1) codeInlineOn:aStream inBlock:b valueNeeded:valueNeeded.

    aStream nextPut:#jump.

    aStream nextPut:pos.

    (aStream contents) at:pos2 put:(aStream position)

!

codeTimesRepeatOn:aStream inBlock:b valueNeeded:valueNeeded

    "generate code for n timesRepeat:[ ... ]"