"
 COPYRIGHT (c) 1994 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.
"

PrimaryNode subclass:#VariableNode
	instanceVariableNames:'name token selfValue selfClass index block'
	classVariableNames:''
	poolDictionaries:''
	category:'System-Compiler-Support'
!

!VariableNode class methodsFor:'documentation'!

copyright
"
 COPYRIGHT (c) 1994 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.
"
!

documentation
"
    node for parse-trees, representing variables
    This is a helper class for the compiler.

    [author:]
        Claus Gittinger
"
! !

!VariableNode class methodsFor:'instance creation'!

type:t class:class name:n
    ^ (self basicNew) type:t class:class name:n
!

type:t index:i selfValue:s
    ^ (self basicNew) type:t index:i selfValue:s
!

type:t name:n
    ^ (self basicNew) type:t name:n
!

type:t name:n index:i selfClass:s
    ^ (self basicNew) type:t name:n index:i selfClass:s
!

type:t name:n index:i selfValue:s
    ^ (self basicNew) type:t name:n index:i selfValue:s
!

type:t name:n token:tok index:i
    ^ (self basicNew) type:t name:n token:tok index:i
!

type:t name:n token:tok index:i block:b
    ^ (self basicNew) type:t name:n token:tok index:i block:b
!

type:t name:n value:val
    ^ (self basicNew) type:t name:n value:val
!

type:t token:tok
    ^ (self basicNew) type:t token:tok
!

type:t token:tok index:i
    ^ (self basicNew) type:t token:tok index:i
!

type:t token:tok index:i block:b
    ^ (self basicNew) type:t token:tok index:i block:b
! !

!VariableNode methodsFor:'accessing'!

index
    ^ index
!

name
    ^ name
!

type:t class:class name:n
    type := t.
    value := nil.
    name := n.
    selfClass := class 
!

type:t index:i selfValue:s
    type := t.
    value := nil.
    index := i.
    selfValue := s
!

type:t name:n
    type := t.
    value := nil.
    name := n
!

type:t name:n index:i selfClass:s
    type := t.
    value := nil.
    index := i.
    selfClass := s.
    name := n
!

type:t name:n index:i selfValue:s
    type := t.
    value := nil.
    index := i.
    selfValue := s.
    name := n
!

type:t name:n token:tok index:i
    type := t.
    index := i.
    token := tok.
    name := n
!

type:t name:n token:tok index:i block:b
    type := t.
    index := i.
    block := b.
    token := tok.
    name := n
!

type:t name:n value:val
    type := t.
    name := n.
    value := val
!

type:t token:tok
    type := t.
    token := tok
!

type:t token:tok index:i
    type := t.
    index := i.
    token := tok
!

type:t token:tok index:i block:b
    type := t.
    index := i.
    block := b.
    token := tok
! !

!VariableNode methodsFor:'code generation'!

codeForSideEffectOn:aStream inBlock:b for:aCompiler
    "no code at all"
    ^ self
!

codeOn:aStream inBlock:codeBlock for:aCompiler
    |theCode b deltaLevel litIndex|

    (type == #MethodArg) ifTrue:[
        (index <= 4) ifTrue:[
            aStream nextPut:(#(pushMethodArg1
                               pushMethodArg2
                               pushMethodArg3 
                               pushMethodArg4) at:index).
            ^ self
        ].
        aStream nextPut:#pushMethodArg; nextPut:index.
        ^ self
    ].
    (type == #MethodVariable) ifTrue:[
        (index <= 6) ifTrue:[
            aStream nextPut:(#(pushMethodVar1
                               pushMethodVar2
                               pushMethodVar3
                               pushMethodVar4
                               pushMethodVar5
                               pushMethodVar6) at:index).
            ^ self
        ].
        aStream nextPut:#pushMethodVar; nextPut:index.
        ^ self
    ].
    (type == #InstanceVariable) ifTrue:[
        (index <= 10) ifTrue:[
            theCode := #(pushInstVar1 pushInstVar2 pushInstVar3
                         pushInstVar4 pushInstVar5 pushInstVar6
                         pushInstVar7 pushInstVar8 pushInstVar9
                         pushInstVar10) at:index.
            aStream nextPut:theCode.
            ^ self
        ].
        aStream nextPut:#pushInstVar; nextPut:index.
        ^ self
    ].
    (type == #BlockArg) ifTrue:[
        "find deltaLevel to block, where argument was defined"
        b := codeBlock.
        deltaLevel := 0.
        [b notNil and:[b ~~ block]] whileTrue:[
            b inlineBlock ifFalse:[
                deltaLevel := deltaLevel + 1
            ].
            b := b home
        ].
        (deltaLevel == 0) ifTrue:[
            (index <= 4) ifTrue:[
                theCode := #(pushBlockArg1 pushBlockArg2 pushBlockArg3
                             pushBlockArg4) at:index.
                aStream nextPut:theCode.
                ^ self
            ].
            aStream nextPut:#pushBlockArg.
        ] ifFalse:[
            (deltaLevel == 1) ifTrue:[
                aStream nextPut:#pushOuter1BlockArg
            ] ifFalse:[
                (deltaLevel == 2) ifTrue:[
                    aStream nextPut:#pushOuter2BlockArg
                ] ifFalse:[
                    aStream nextPut:#pushOuterBlockArg; nextPut:deltaLevel
                ]
            ].
        ].
        aStream nextPut:index.
        ^ self
    ].
    (type == #GlobalVariable) ifTrue:[
        litIndex := aCompiler addLiteral:name asSymbol.
        (aCompiler isSpecialGlobalSymbol:name) ifTrue:[
            aStream nextPut:#pushSpecialGlobal; nextPut:(aCompiler specialGlobalCodeFor:name).
            ^ self
        ].

        litIndex < 256 ifTrue:[
            aStream nextPut:#pushGlobalS; nextPut:litIndex
        ] ifFalse:[
            aStream nextPut:#pushGlobalL; nextPut:litIndex; nextPut:0
        ].
        ^ self
    ].
    (type == #ClassVariable) ifTrue:[
        litIndex := aCompiler addLiteral:(selfClass name , ':' , name) asSymbol.
        litIndex < 256 ifTrue:[
            aStream nextPut:#pushClassVarS; nextPut:litIndex
        ] ifFalse:[
            aStream nextPut:#pushClassVarL; nextPut:litIndex; nextPut:0
        ].
        ^ self
    ].
    (type == #PrivateClass) ifTrue:[
        litIndex := aCompiler addLiteral:(selfClass name , '::' , name) asSymbol.
        litIndex < 256 ifTrue:[
            aStream nextPut:#pushGlobalS; nextPut:litIndex
        ] ifFalse:[
            aStream nextPut:#pushGlobalL; nextPut:litIndex; nextPut:0
        ].
        ^ self
    ].
    (type == #BlockVariable) ifTrue:[
        "find deltaLevel to block, where variable was defined"
        b := codeBlock.
        deltaLevel := 0.
        [b notNil and:[b ~~ block]] whileTrue:[
            b inlineBlock ifFalse:[
                deltaLevel := deltaLevel + 1
            ].
            b := b home
        ].

        (deltaLevel == 0) ifTrue:[
            index <= 3 ifTrue:[
                aStream nextPut:(#(pushBlockVar1 pushBlockVar2 pushBlockVar3) at:index).
                ^ self
            ].
            aStream nextPut:#pushBlockVar.
        ] ifFalse:[
            aStream nextPut:#pushOuterBlockVar; nextPut:deltaLevel.
        ].
        aStream nextPut:index.
        ^ self
    ].
    (type == #ClassInstanceVariable) ifTrue:[
        aStream nextPut:#pushClassInstVar; nextPut:index.
        ^ self
    ].
    (type == #ThisContext) ifTrue:[
        aStream nextPut:#pushThisContext. ^ self
    ].

    "not reached"
    self halt:'bad type'.

    "Modified: 14.10.1996 / 19:43:18 / cg"
!

codeStoreOn:aStream inBlock:codeBlock valueNeeded:valueNeeded for:aCompiler
    |theCode b deltaLevel litIndex|

    valueNeeded ifTrue:[
        aStream nextPut:#dup
    ].
    (type == #MethodVariable) ifTrue:[
        (index <= 6) ifTrue:[
            theCode := #(storeMethodVar1 storeMethodVar2
                         storeMethodVar3 storeMethodVar4
                         storeMethodVar5 storeMethodVar6) at:index.
            aStream nextPut:theCode.
            ^ self
        ].
        aStream nextPut:#storeMethodVar; nextPut:index.
        ^ self
    ].
    (type == #InstanceVariable) ifTrue:[
        (index <= 10) ifTrue:[
            theCode := #(storeInstVar1 storeInstVar2
                         storeInstVar3 storeInstVar4
                         storeInstVar5 storeInstVar6
                         storeInstVar7 storeInstVar8
                         storeInstVar9 storeInstVar10) at:index.
            aStream nextPut:theCode.
            ^ self
        ].
        aStream nextPut:#storeInstVar; nextPut:index.
        ^ self
    ].
    (type == #BlockVariable) ifTrue:[
        "find deltaLevel to block, where variable was defined"
        b := codeBlock.
        deltaLevel := 0.
        [b notNil and:[b ~~ block]] whileTrue:[
            b inlineBlock ifFalse:[
                deltaLevel := deltaLevel + 1
            ].
            b := b home
        ].

        (deltaLevel == 0) ifTrue:[
            index <= 3 ifTrue:[
                aStream nextPut:(#(storeBlockVar1 storeBlockVar2 storeBlockVar3) at:index).
                ^ self
            ].
            aStream nextPut:#storeBlockVar
        ] ifFalse:[
            aStream nextPut:#storeOuterBlockVar; nextPut:deltaLevel
        ].
        aStream nextPut:index.
        ^ self
    ].
    (type == #GlobalVariable) ifTrue:[
        litIndex := aCompiler addLiteral:name asSymbol.
        litIndex < 256 ifTrue:[
            aStream nextPut:#storeGlobalS; nextPut:litIndex
        ] ifFalse:[
            aStream nextPut:#storeGlobalL; nextPut:litIndex; nextPut:0
        ].
        ^ self
    ].
    (type == #ClassVariable) ifTrue:[
        litIndex := aCompiler addLiteral:(selfClass name , ':' , name) asSymbol.
        litIndex < 256 ifTrue:[
            aStream nextPut:#storeClassVarS; nextPut:litIndex
        ] ifFalse:[
            aStream nextPut:#storeClassVarL; nextPut:litIndex; nextPut:0
        ].
        ^ self
    ].
    (type == #ClassInstanceVariable) ifTrue:[
        aStream nextPut:#storeClassInstVar; nextPut:index.
        ^ self
    ].
    "not reached"
    ^ self error:'bad assignment'

    "Modified: 29.2.1996 / 23:54:38 / cg"
! !

!VariableNode methodsFor:'evaluating'!

evaluate
    (type == #MethodVariable
    or:[type == #BlockArg
    or:[type == #BlockVariable]]) ifTrue:[
        ^ token variableValue
    ].
    (type == #InstanceVariable) ifTrue:[
        ^ selfValue instVarAt:index
    ].
    (type == #GlobalVariable) ifTrue:[
        (Smalltalk includesKey:name) ifTrue:[
            ^ Smalltalk at:name
        ].
"
        self error:('global ' , name , ' is undefined').
"

        ^ UndefinedVariable name:name.
        ^ nil
    ].
    (type == #ClassVariable) ifTrue:[
        ^ Smalltalk at:(selfClass name , ':' , name) asSymbol
    ].
    (type == #ClassInstanceVariable) ifTrue:[
        ^ selfClass instVarAt:index
    ].
    (type == #ThisContext) ifTrue:[
        ^ thisContext
    ].
    (type == #PrivateClass) ifTrue:[
        ^ selfClass privateClassesAt:name asSymbol
    ].
    "not reached"
    self halt:'bad type'.
    ^ value

    "Modified: 6.11.1996 / 17:28:17 / cg"
!

store:aValue
    (type == #MethodVariable
    or:[type == #BlockVariable]) ifTrue:[
	token value:aValue. ^ aValue
    ].
    (type == #InstanceVariable) ifTrue:[
	^ selfValue instVarAt:index put:aValue
    ].
    (type == #GlobalVariable) ifTrue:[
	^ Smalltalk at:name put:aValue
    ].
    (type == #ClassVariable) ifTrue:[
	^ Smalltalk at:(selfClass name , ':' , name) asSymbol put:aValue
    ].
    (type == #ClassInstanceVariable) ifTrue:[
	^ selfClass instVarAt:index put:aValue
    ].
    "not reached"
    self halt:'bad type'.
    ^ aValue
! !

!VariableNode methodsFor:'printing'!

displayString
    ^ 'InterpreterVariable(' , self printString , ')'
!

printOn:aStream indent:i

    (type == #MethodArg              "/ actually only a debug-check
    or:[type == #MethodVariable
    or:[type == #InstanceVariable
    or:[type == #BlockArg
    or:[type == #GlobalVariable
    or:[type == #ClassVariable
    or:[type == #BlockVariable
    or:[type == #ClassInstanceVariable]]]]]]]) ifTrue:[
	aStream nextPutAll:name. ^ self
    ].
    (type == #ThisContext) ifTrue:[
	aStream nextPutAll:'thisContext'. ^ self
    ].
    "not reached"
    self halt:'bad type'.
! !

!VariableNode methodsFor:'queries'!

canReuseAsArg:anotherNode
    anotherNode isVariable ifTrue:[
        anotherNode type ~~ type ifTrue:[^ false].

        (type == #ThisContext) ifTrue:[^ true].

        index notNil ifTrue:[
            anotherNode index ~~ index ifTrue:[^ false].
        ].
        (type == #MethodArg) ifTrue:[^ true].
        (type == #MethodVariable) ifTrue:[^ true].
        (type == #InstanceVariable) ifTrue:[^ true].

        name notNil ifTrue:[
            anotherNode name ~~ name ifTrue:[^ false].
        ].
        (type == #GlobalVariable) ifTrue:[^ true].
        (type == #ClassVariable) ifTrue:[^ true].
    ].
    ^ false

    "Created: 14.4.1996 / 00:46:18 / cg"
    "Modified: 14.4.1996 / 00:55:25 / cg"
!

isGlobal
    "return true, if this is a node for a global variable"

    ^ (type == #GlobalVariable) and:[Smalltalk includesKey:name]
!

isLocal
    "return true, if this is a node for a local (block or method) variable"

    ^ (type == #MethodVariable) or:[type == #BlockVariable]

    "Created: 1.3.1996 / 00:03:53 / cg"
    "Modified: 1.3.1996 / 00:04:46 / cg"
!

isVariable
    "return true, if this is a node for a variable"

    ^ true

    "Created: 14.4.1996 / 00:46:32 / cg"
! !

!VariableNode class methodsFor:'documentation'!

version
    ^ '$Header: /cvs/stx/stx/libcomp/VariableNode.st,v 1.23 1996-11-07 13:58:57 cg Exp $'
! !