Eliot Miranda uploaded a new version of Tools to project The Trunk: http://source.squeak.org/trunk/Tools-eem.633.mcz
==================== Summary ====================
Name: Tools-eem.633 Author: eem Time: 17 September 2015, 1:18:07.129 pm UUID: 2a5a8395-fa44-4d48-b6ed-a920c18dbc02 Ancestors: Tools-mt.632
Fix hard VM crash when defining quick methods from MNUs in the debugger. The bug is that the sender context (Message>>sentTo:) is doing a perform:withArguments:[inSuperclass:] but the receiver and arguments have already been removed from the context, so simply backing up to the point of send and proceeding will have disastrous consequences; there must be a receiver and arguments on the stack. So if the arguments are unavailable we simply restart the context inmstead of backing up to the point of send.
To reproduce: 0. make sure e.g. Object>>#zork is unimplemented 1. evaluate "nil zork" 2. in the debugger examine the doesNotUnderstand: context and then hit proceed. 3. click the Create button and define Object>>#zork ^nil 4. (the debugger sets the active context to Message>>sentTo:) hit proceed
Before the VM woudl crash. Now the debugger sets the pc to the start of the Message>>sentTo: method.
=============== Diff against Tools-mt.632 ===============
Item was changed: ----- Method: Debugger>>contents:notifying: (in category 'accessing') ----- contents: aText notifying: aController "The retrieved information has changed and its source must now be updated. In this case, the retrieved information is the method of the selected context." | result selector classOfMethod category h ctxt newMethod | contextStackIndex = 0 ifTrue: [^false]. self selectedContext isExecutingBlock ifTrue: [h := self selectedContext activeHome. h ifNil: [self inform: 'Method for block not found on stack, can''t edit and continue'. ^false]. (self confirm: 'I will have to revert to the method from\which this block originated. Is that OK?' withCRs) ifFalse: [^false]. self resetContext: h changeContents: false. "N.B. Only reset the contents if the compilation succeeds. If contents are reset when compilation fails both compiler error message and modifications are lost." (result := self contents: aText notifying: aController) ifTrue: [self contentsChanged]. ^result].
classOfMethod := self selectedClass. category := self selectedMessageCategoryName. selector := self selectedClass newParser parseSelector: aText. (selector == self selectedMessageName or: [(self selectedMessageName beginsWith: 'DoIt') and: [selector numArgs = self selectedMessageName numArgs]]) ifFalse: [self inform: 'can''t change selector'. ^false]. selector := classOfMethod compile: aText classified: category notifying: aController. selector ifNil: [^false]. "compile cancelled" contents := aText. newMethod := classOfMethod compiledMethodAt: selector. newMethod isQuick ifTrue: + [self cutBackExecutionToSenderContext]. - [self down. - self selectedContext jump: (self selectedContext previousPc - self selectedContext pc)]. ctxt := interruptedProcess popTo: self selectedContext. ctxt == self selectedContext ifFalse: [self inform: 'Method saved, but current context unchanged\because of unwind error. Click OK to see error' withCRs] ifTrue: [newMethod isQuick ifFalse: [interruptedProcess restartTopWith: newMethod; stepToSendOrReturn]. contextVariablesInspector object: nil]. self resetContext: ctxt. Smalltalk isMorphic ifTrue: [World addAlarm: #changed: withArguments: #(contentsSelection) for: self at: (Time millisecondClockValue + 200)]. ^true!
Item was added: + ----- Method: Debugger>>cutBackExecutionToSenderContext (in category 'private') ----- + cutBackExecutionToSenderContext + "When accepting a new version of a method which can't be simulated (i.e. a quick method) we + must cut back to the sender. But this is non-trivial. If the quick method has been reached via + a perform: (as it is when one uses Create toi implement a method from an MNU) then the relevant + arguments won't be on the stack and we can't simply proceed without crashing the VM." + | oldContext context sel | + oldContext := self selectedContext. + self down. + context := self selectedContext. + context jump: (context previousPc - context pc). + sel := context selectorToSendOrSelf. + sel numArgs = oldContext method numArgs + ifTrue: + [context push: oldContext receiver. + oldContext arguments do: + [:arg| context push: arg]] + ifFalse: + [context privRefresh; stepToSendOrReturn]!