[Vm-dev] VM Maker: VMMaker.oscog-eem.2904.mcz

commits at source.squeak.org commits at source.squeak.org
Mon Nov 30 20:09:15 UTC 2020

Eliot Miranda uploaded a new version of VMMaker to project VM Maker:

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

Name: VMMaker.oscog-eem.2904
Author: eem
Time: 30 November 2020, 12:09:05.818551 pm
UUID: 8569e47f-67b4-4e80-9af6-303a01f7c2c3
Ancestors: VMMaker.oscog-eem.2903

MTVM: fix preemptDisowningThread; marryFrame:SP: expects top-of-stack to be the Smalltalk top-of-stack, not a pushed instructionPointer.

=============== Diff against VMMaker.oscog-eem.2903 ===============

Item was changed:
  ----- Method: CoInterpreterMT>>preemptDisowningThread (in category 'vm scheduling') -----
  	"Set the relevant state for disowningVMThread so that it can resume after
  	 being preempted and set disowningVMThread to nil to indicate preemption.
  	 N.B.  This should only be sent from checkPreemptionOfDisowningThread.
  	 There are essentially four things to do.
  	 a)	save the VM's notion of the current C stack pointers; these are pointers
  		into a thread's stack and must be saved and restored in thread switch.
  	 b)	save the VM's notion of the current Smalltalk execution point.  This is
  		simply the suspend half of a process switch that saves the current context
  		in the current process.
  	 c)	add the process to the thread's set of AWOL processes so that the scheduler
  		won't try to run the process while the thread has disowned the VM.
  	 d)	save the in-primitive VM state, newMethod and argumentCount
  	 ownVM: will restore the VM context as of disownVM: from the above when it
  	 finds it has been preempted."
  	| activeProc activeContext preemptedThread |
  	<var: #preemptedThread type: #'CogVMThread *'>
  	<inline: false>
  	self assert: disowningVMThread notNil.
  	self assert: (disowningVMThread state = CTMUnavailable
  				or: [disowningVMThread state = CTMWantingOwnership]).
  	self assertCStackPointersBelongToDisowningThread.
  	cogit recordEventTrace ifTrue:
  		[self recordTrace: TracePreemptDisowningThread
  			thing: (objectMemory integerObjectOf: disowningVMThread index)
  			source: 0].
  	disowningVMThread cStackPointer: CStackPointer.
  	disowningVMThread cFramePointer: CFramePointer.
  	activeProc := self activeProcess.
  	self assert: (objectMemory fetchPointer: MyListIndex ofObject: activeProc) = objectMemory nilObject.
  		storePointer: MyListIndex
  		ofObject: activeProc
  		withValue: (objectMemory splObj: ProcessInExternalCodeTag).
+ 	activeContext := self ensureFrameIsMarried: framePointer SP: stackPointer.
+ 	objectMemory
+ 		storePointer: SuspendedContextIndex
+ 		ofObject: activeProc
+ 		withValue: activeContext.
  	"The instructionPointer must be pushed because the convention for inactive stack pages is that the
  	 instructionPointer is top of stack.  We need to know if this primitive is called from machine code
  	 because the invariant that the return pc of an interpreter callee calling a machine code caller is
  	 ceReturnToInterpreterPC must be maintained."
  	self push: instructionPointer.
  	self externalWriteBackHeadFramePointers.
- 	activeContext := self ensureFrameIsMarried: framePointer SP: stackPointer.
- 	objectMemory
- 		storePointer: SuspendedContextIndex
- 		ofObject: activeProc
- 		withValue: activeContext.
  	"Since pushing the awol process may realloc disowningVMThread we need to reassign.
  	 But since we're going to nil disowningVMThread anyway we can assign to a local."
  	preemptedThread := cogThreadManager pushAWOLProcess: activeProc on: disowningVMThread.
  	disowningVMThread := nil.
  	preemptedThread priority: (self quickFetchInteger: PriorityIndex ofObject: activeProc).
  	(self ownerIndexOfProcess: activeProc) = 0
  		ifTrue: [self setOwnerIndexOfProcess: activeProc to: preemptedThread index bind: false]
  		ifFalse: [self assert: (self ownerIndexOfProcess: activeProc) = preemptedThread index].
  		newMethodOrNull: newMethod;
  		argumentCount: argumentCount;
  		primitiveFunctionPointer: primitiveFunctionPointer;
  		inMachineCode: instructionPointer asUnsignedInteger <= objectMemory startOfMemory!

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