[squeak-dev] Decompiling with temps
Bert Freudenberg
bert at freudenbergs.de
Thu Jan 13 10:29:50 UTC 2011
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?
- 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
More information about the Squeak-dev
mailing list
|