On Thu, Jan 13, 2011 at 9:33 AM, Eliot Miranda <eliot.miranda at gmail.com>wrote:

>
>
> On Thu, Jan 13, 2011 at 2:29 AM, Bert Freudenberg <bert at freudenbergs.de>wrote:
>
>> Here's another decompiler problem that I actually ran into in production
>> code. When decompiling this method, either the block-local temp should
>> remain block-local, or one of the vars needs to be renamed:
>>
>> blockLocalsAndArgs
>>        | product |
>>        product := 1.
>>        1 to: 2 do: [:i |
>>                i = 1
>>                        ifTrue: [ | factor | factor := 6.
>>                                product := product * factor ]
>>                        ifFalse: [ #(9) do: [:factor |
>>                                product := product * factor ] ] ].
>>        ^ product = 13r42
>>
>> This works fine if decompiled without temps but the standard in Squeak is
>> to use the actual temp names - just accept this as a method and switch to
>> decompiled view.
>>
>> The best fix might be if the decompiler always declared the variables in
>> the inner-most block possible. Maybe moving the declarations is not even
>> that hard to do as a post-process on the AST?
>>
>
> Right.  And there's now a visitor method for determining that scope,
> TempScopeEditor>>#blockNode:isEnclosingScopeFor:.  But I've been too
> lazy^H^H^H^Hbusy to apply it in the context of the decompiler.  Feel free to
> feel motivated...
>

No, no, no, no, no, no, no.  The visitor is VariableScopeFinder and the
method is ofVariable: so aParseNode accept: (VariableScopeFinder new
ofVariable: var) answers nil or the smallest enclosing scope for var in
aParseNode.  See Parser>>declareUndeclaredTemps.


> best
> Eliot
>
>
>>
>> - Bert -
>>
>> On 13.01.2011, at 00:51, Nicolas Cellier wrote:
>>
>> > Follow up on unused temps :
>> >
>> > Wanna play with temps ? Try this :
>> >
>> > testUnusedVariable
>> >       self
>> >               compiling: 'griffle | goo | ^nil'
>> >               shouldRaise: UnusedVariable;
>> >               compiling: 'griffle | | ^[ | goo | ]'
>> >               shouldRaise: UnusedVariable;
>> >               compiling: 'griffle | | [ | goo | goo := nil. goo]
>> yourself. ^[ | goo | ]'
>> >               shouldRaise: UnusedVariable;
>> >               compiling: 'griffle | | [ | goo | ] yourself. ^[ | goo |
>> goo := nil. goo]'
>> >               shouldRaise: UnusedVariable
>> >
>> > What happens is that Parser.scopeTable has a single entry for 'goo'.
>> > Consequently, the last registered goo wins.
>> > In the 3rd case, the last goo is unused, so hasRef = false, so
>> > UnusedVariable is raised.
>> > In the 4th case, the last goo nowHasRef, and we don't get any
>> UnusedVariable.
>> >
>> > Until we get a scopeTable mapping each temp of each block, we gonna
>> > live in trouble.
>> >
>> > Nicolas
>>
>>
>>
>>
>
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