[Vm-dev] VM Maker: VMMaker.oscog-nice.1843.mcz

commits at source.squeak.org commits at source.squeak.org
Mon Apr 25 19:23:45 UTC 2016


Nicolas Cellier uploaded a new version of VMMaker to project VM Maker:
http://source.squeak.org/VMMaker/VMMaker.oscog-nice.1843.mcz

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

Name: VMMaker.oscog-nice.1843
Author: nice
Time: 25 April 2016, 8:24:03.731 pm
UUID: 9ef5d374-ae5e-437a-9116-cde9d708c0d7
Ancestors: VMMaker.oscog-cb.1842

Fix my recent bug for signed 32bit long access (introduced beginning of April).

One symptom is:
  (Alien newGC: 4)
	signedLongAt: 1 put: -16r7287E552;
	signedLongAt: 1

I incorrecly used the signed value (integerValue) in one branch, and the magnitude (value) in the other branch...
This is an incorrect copy/paste from maybeInlinePositive32BitIntegerFor: in my ultimate #if SPURVM refactoring.

While at it, avoid the confusion by using a better variable name (magnitude), and eliminate UB related to computing opposite of INT_MIN by explicitely using unsigned type.

=============== Diff against VMMaker.oscog-cb.1842 ===============

Item was changed:
  ----- Method: StackInterpreter>>noInlineSigned32BitIntegerFor: (in category 'primitive support') -----
  noInlineSigned32BitIntegerFor: integerValue
  	"Answer a full 32 bit integer object for the given integer value."
  	<notOption: #Spur64BitMemoryManager>
+ 	| newLargeInteger magnitude largeClass |
- 	| newLargeInteger value largeClass |
  	<inline: false>
+ 	<var: 'magnitude' type: 'unsigned int'>
  	(objectMemory isIntegerValue: integerValue) ifTrue:
  		[^objectMemory integerObjectOf: integerValue].
  	self deny: objectMemory hasSixtyFourBitImmediates.
  	 integerValue < 0
  		ifTrue: [largeClass := ClassLargeNegativeIntegerCompactIndex.
+ 				magnitude := 0 asUnsignedInteger - integerValue]
- 				value := 0 - integerValue]
  		ifFalse: [largeClass := ClassLargePositiveIntegerCompactIndex.
+ 				magnitude := integerValue].
- 				value := integerValue].
  	newLargeInteger := objectMemory
  							eeInstantiateSmallClassIndex: largeClass
  							format: (objectMemory byteFormatForNumBytes: 4)
  							numSlots: 1.
  	self cppIf: SPURVM
  		ifTrue:
  			["Memory is 8 byte aligned in Spur, make sure that oversized bytes are set to zero"
+ 			objectMemory storeLong32: 0 ofObject: newLargeInteger withValue: (objectMemory byteSwapped32IfBigEndian: magnitude).
- 			objectMemory storeLong32: 0 ofObject: newLargeInteger withValue: (objectMemory byteSwapped32IfBigEndian: integerValue).
  			objectMemory storeLong32: 1 ofObject: newLargeInteger withValue: 0]
  		ifFalse: 
+ 			[objectMemory storeLong32: 0 ofObject: newLargeInteger withValue: (objectMemory byteSwapped32IfBigEndian: magnitude)].
- 			[objectMemory storeLong32: 0 ofObject: newLargeInteger withValue: (objectMemory byteSwapped32IfBigEndian: value)].
  	^newLargeInteger!



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