[Pkg] The Trunk: Compiler-eem.251.mcz
commits at source.squeak.org
commits at source.squeak.org
Mon Feb 11 21:12:19 UTC 2013
Eliot Miranda uploaded a new version of Compiler to project The Trunk:
http://source.squeak.org/trunk/Compiler-eem.251.mcz
==================== Summary ====================
Name: Compiler-eem.251
Author: eem
Time: 11 February 2013, 1:11:53.981 pm
UUID: caeb538b-aaa9-46a5-b43c-51dec9220273
Ancestors: Compiler-eem.250
Yet another fix for decompilation of to:do: loops compiled
with Compiler-nice.224 or later. If the stack is non-empty
when convertDoDoLoop is invoked, the stack must be left
non-empty. This fixes decompilation of e.g.
^nil to: 3 do: [:i| i class]
=============== Diff against Compiler-eem.250 ===============
Item was changed:
----- Method: Decompiler>>convertToDoLoop (in category 'private') -----
convertToDoLoop
"If statements contains the pattern
var := startExpr.
[var <= limit] whileTrue: [...statements... var := var + incConst]
then replace this by
startExpr to: limit by: incConst do: [:var | ...statements...]"
+ | leaveOnStack initStmt toDoStmt limitStmt |
+ leaveOnStack := false.
- | initStmt toDoStmt limitStmt |
(stack notEmpty
and: [stack last isAssignmentNode])
ifTrue:
[initStmt := stack last.
(toDoStmt := statements last toDoFromWhileWithInit: initStmt) ifNil:
[^self].
stack removeLast.
+ statements removeLast; addLast: toDoStmt.
+ leaveOnStack := true]
- statements removeLast; addLast: toDoStmt]
ifFalse:
[statements size < 2 ifTrue:
[^self].
initStmt := statements at: statements size-1.
(toDoStmt := statements last toDoFromWhileWithInit: initStmt) ifNil:
[^self].
statements removeLast; removeLast; addLast: toDoStmt].
initStmt variable scope: -1. "Flag arg as block temp"
"Attempt further conversion of the pattern
limitVar := limitExpr.
startExpr to: limitVar by: incConst do: [:var | ...statements...]
to
startExpr to: limitExpr by: incConst do: [:var | ...statements...].
The complication here is that limitVar := limitExpr's value may be used, in which case it'll
be statements last, or may not be used, in which case it'll be statements nextToLast."
+ statements size < 2 ifTrue:
+ [^self].
- statements size < 2 ifTrue: [^ self].
limitStmt := statements last.
((limitStmt isMemberOf: AssignmentNode)
and: [limitStmt variable isTemp
and: [limitStmt variable == toDoStmt arguments first]]) ifFalse:
[limitStmt := statements at: statements size-1.
((limitStmt isMemberOf: AssignmentNode)
and: [limitStmt variable isTemp
and: [limitStmt variable == toDoStmt arguments first]]) ifFalse:
+ [leaveOnStack ifTrue:
+ [stack addLast: statements removeLast].
+ ^self]].
- [^self]].
(self blockScopeRefersOnlyOnceToTemp: limitStmt variable fieldOffset) ifFalse:
[^self].
toDoStmt arguments at: 1 put: limitStmt value.
limitStmt variable scope: -2. "Flag limit var so it won't print"
statements last == limitStmt
ifTrue: [statements removeLast]
ifFalse: [statements removeLast; removeLast; addLast: toDoStmt]!
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