[Vm-dev] VM Maker: VMMaker.oscog-eem.792.mcz

[commits at source.squeak.org]

Eliot Miranda uploaded a new version of VMMaker to project VM Maker:
http://source.squeak.org/VMMaker/VMMaker.oscog-eem.792.mcz

==================== Summary ====================

Name: VMMaker.oscog-eem.792
Author: eem
Time: 1 July 2014, 8:08:46.954 pm
UUID: 9d8d23c8-c855-48a6-8bdd-402765c01a99
Ancestors: VMMaker.oscog-eem.791

Fix potential liveness of ReceiverResultReg across counting
jumps by reloading ReceiverResultReg before returning from
the trampoline through which ceCounterTripped: is called.

=============== Diff against VMMaker.oscog-eem.791 ===============

Item was changed:
  ----- Method: SistaStackToRegisterMappingCogit>>genMustBeBooleanTrampolineFor:called: (in category 'initialization') -----
  genMustBeBooleanTrampolineFor: boolean called: trampolineName
  	"This can be entered in one of two states, depending on SendNumArgsReg. See
  	 e.g. genJumpIf:to:.  If SendNumArgsReg is non-zero then this has been entered via
  	 the initial test of the counter in the jump executed count (i.e. the counter has
  	 tripped).  In this case TempReg contains the boolean to be tested and should not
  	 be offset, and ceCounterTripped should be invoked with the unoffset TempReg.
  	 If SendNumArgsReg is zero then this has been entered for must-be-boolean
  	 processing. TempReg has been offset by boolean and must be corrected and
  	 ceSendMustBeBoolean: invoked with the corrected value."
  	<var: #trampolineName type: #'char *'>
  	| jumpMBB |
  	<var: #jumpMBB type: #'AbstractInstruction *'>
  	<inline: false>
  	opcodeIndex := 0.
  	self CmpCq: 0 R: SendNumArgsReg.
  	jumpMBB := self JumpZero: 0.
+ 	"Open-code self compileTrampolineFor: #ceCounterTripped: numArgs: 1 arg: TempReg ...
+ 	 so we can restore ResultReceiverReg."
+ 	backEnd hasLinkRegister ifTrue:
+ 		[self PushR: LinkReg].
+ 	self genSmalltalkToCStackSwitch.
+ 	self
+ 		compileCallFor: #ceCounterTripped:
- 	self compileTrampolineFor: #ceCounterTripped:
  		numArgs: 1
  		arg: TempReg
  		arg: nil
  		arg: nil
  		arg: nil
+ 		resultReg: TempReg "(*)"
+ 		saveRegs: false.
+ 	"(*) For the case where the ceCounterTripped: call returns (e.g. because there's no callback selector
- 		saveRegs: false
- 		pushLinkReg: true
- 		resultReg: nil.
- 	"For the case where the ceCounterTripped: call returns (e.g. because there's no callback selector
  	 installed), the call to the ceSendMustBeBooleanAddTrue/FalseTrampoline is followed by a jump
  	 back to the start of the counter/condition test sequence.  For this case copy the C result to
  	 TempReg (the register that is tested), to reload it with the boolean to be tested."
+ 	backEnd genLoadStackPointers.
+ 	backEnd hasLinkRegister ifTrue:
+ 		[self PopR: LinkReg].
+ 	"To keep ResultReceiverReg live if optStatus thiught it was, simply reload it
+ 	 from the frame pointer.  This avoids having to reload it in the common case
+ 	 (counter does not trip) if it was live."
+ 	self MoveMw: FoxMFReceiver r: FPReg R: ReceiverResultReg.
+ 	self RetN: 0.
- 	backEnd cResultRegister ~= TempReg ifTrue:
- 		[self MoveR: backEnd cResultRegister R: TempReg].
  	"If the objectRepresentation does want true & false to be mobile then we need to record these addresses."
  	self assert: (objectRepresentation shouldAnnotateObjectReference: boolean) not.
  	jumpMBB jmpTarget: (self AddCq: boolean R: TempReg).
  	^self genTrampolineFor: #ceSendMustBeBoolean:
  		called: trampolineName
  		numArgs: 1
  		arg: TempReg
  		arg: nil
  		arg: nil
  		arg: nil
  		saveRegs: false
  		pushLinkReg: true
  		resultReg: nil
  		appendOpcodes: true!