[Vm-dev] VM Maker: VMMaker.oscog-eem.3091.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.3091.mcz

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

Name: VMMaker.oscog-eem.3091
Author: eem
Time: 15 October 2021, 7:16:26.376829 pm
UUID: 264f2183-0530-4514-8a64-3e03a75335fa
Ancestors: VMMaker.oscog-eem.3090

ARMv8 8.1: fix generateLowLevelTryLock: so that it answers if vmOwner is set to the desired value (i.e. if already set to the desired value, still answer true).

Comment the cack-handed hack in withProcessorHaltedDo: and have the code not destroy a break pc within ceTryLockVMOwner.

firstMappedPCFor: needs a guard.

Fix a couple of comments.

=============== Diff against VMMaker.oscog-eem.3090 ===============

Item was changed:
  ----- Method: CogARMCompiler>>hasDoublePrecisionFloatingPointSupport (in category 'testing') -----
  hasDoublePrecisionFloatingPointSupport
- 	"might be true, but is for the forseeable future disabled"
  	^true!

Item was changed:
  ----- Method: CogARMv8Compiler>>generateLowLevelTryLock: (in category 'multi-threading') -----
  generateLowLevelTryLock: vmOwnerLockAddress
  	"Generate a function that attempts to lock the vmOwnerLock to the argument and answers if it succeeded."
  	<inline: true>
  	| lockValueReg vmOwnerLockAddressReg br statusReg ldaxr |
  	vmOwnerLockAddress = 0 ifTrue:
  		[cogit
  			MoveCq: 1 R: ABIResultReg;
  			RetN: 0.
  		 ^self].
  
  	"spiffy 8.1 version using CASAL..."
  	lockValueReg := CArg1Reg. "Holds the value of lock if unlocked (zero), receives the existing value of the lock"
  	vmOwnerLockAddressReg := CArg2Reg.
  	self hasAtomicInstructions ifTrue:
  		[cogit
  			MoveCq: 0 R: lockValueReg;
  			MoveCq: vmOwnerLockAddress R: vmOwnerLockAddressReg;
+ 			gen: CASAL operand: lockValueReg operand: CArg0Reg operand: vmOwnerLockAddressReg.
+ br :=	cogit gen: CBNZ operand: 0 operand: lockValueReg.
+ 		cogit
+ 			MoveCq: 1 R: ABIResultReg;
- 			gen: CASAL operand: lockValueReg operand: CArg0Reg operand: vmOwnerLockAddressReg;
- 			CmpCq: 0 R: lockValueReg;
- 			gen: CCMPNE operand: ABIResultReg operand: lockValueReg operand: 0 "nzcv all false"; "i.e. if NE to 0, then is it already set to the argument?"
- 			gen: CSET operand: ABIResultReg operand: EQ;
  			RetN: 0.
+ br jmpTarget: (cogit CmpR: ABIResultReg R: lockValueReg).
+ 		cogit
+ 			gen: CSET operand: ABIResultReg operand: EQ; "i.e. if NE to 0, then is it already set to the argument?"
+ 			RetN: 0.
  		 ^self].
  
  	"frumpy 8.0 version using LDAXR/STLXR"
  				cogit MoveCq: vmOwnerLockAddress R: vmOwnerLockAddressReg.
  				cogit MoveCq: 0 R: (statusReg := CArg3Reg). "STLXR sets a word status register; clearing the top bits means it's a non-issue"
  	ldaxr :=	cogit gen: LDAXR operand: lockValueReg operand: vmOwnerLockAddressReg.
  	br :=		cogit gen: CBNZ operand: 0 operand: lockValueReg.
  				cogit gen: STLXR operand: CArg0Reg operand: vmOwnerLockAddressReg operand: statusReg.
  				cogit gen: CBNZ operand: ldaxr asUnsignedInteger operand: statusReg.
  				"Since CArg0Reg is never zero, merely returning answers true"
  				cogit RetN: 0.
  	br jmpTarget: (cogit gen: CLREX).
  				cogit CmpR: ABIResultReg R: lockValueReg.
  				cogit gen: CSET operand: ABIResultReg operand: EQ. "i.e. if NE to 0, then is it already set to the argument?"
  				cogit RetN: 0.
  	 ^self!

Item was changed:
  ----- Method: CogIA32Compiler>>generateLowLevelTryLock: (in category 'multi-threading') -----
  generateLowLevelTryLock: vmOwnerLockAddress
+ 	"Generate a function that attempts to lock the vmOwnerLock and answers if it succeeded."
- 	"Generate a function that attempts to lock the vmOwnerLock and answers
- 	 true if it succeeded."
  	<inline: true>
  	| valueReg |
  	vmOwnerLockAddress = 0 ifTrue:
  		[cogit
  			MoveCq: 1 R: ABIResultReg;
  			RetN: 0.
  		 ^self].
  	valueReg := cogit availableRegisterOrNoneIn: (ABICallerSavedRegisterMask bitClear: 1 << EAX).
  	cogit
  		MoveMw: 4 r: ESP R: valueReg;
  		MoveCq: 0 R: EAX;
  		gen: LOCK;
  		gen: CMPXCHGRAw operand: valueReg operand: vmOwnerLockAddress;
  		gen: SETE operand: ABIResultReg; "a.k.a. EAX"
  		RetN: 0!

Item was changed:
  ----- Method: Cogit>>firstMappedPCFor: (in category 'method map') -----
  firstMappedPCFor: cogMethod
  	<var: #cogMethod type: #'CogMethod *'>
  	<inline: true>
+ 	^(cogMethod cmType < CMClosedPIC and: [cogMethod cmIsFullBlock])
- 	^cogMethod cmIsFullBlock
  		ifTrue: [cogMethod asUnsignedInteger + cbNoSwitchEntryOffset]
  		ifFalse: [cogMethod asUnsignedInteger + cmNoCheckEntryOffset]!

Item was changed:
  ----- Method: Cogit>>withProcessorHaltedDo: (in category 'simulation processor access') -----
  withProcessorHaltedDo: aBlock
  	^processorLock critical:
+ 		["This is a kack-handed attempt at stopping all other threads while this routine is running.
+ 		  Anyway, don't set breakPC to true if trying to break within ceTryLockVMOwner"
+ 		| oldBreakPC oldSingleStep |
- 		[| oldBreakPC oldSingleStep |
  		 oldBreakPC := breakPC.
  		 oldSingleStep := singleStep.
+ 		 singleStep := true.
+ 		 (breakPC isInteger and: [breakPC between: ceTryLockVMOwner and: ceGetFP - 1]) ifFalse:
+ 			[breakPC := true].
- 		 breakPC := singleStep := true.
  		 aBlock ensure:
  			[singleStep := oldSingleStep.
  			 breakPC := oldBreakPC]]!