[Vm-dev] VM Maker: VMMaker.oscog-eem.2006.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.2006.mcz

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

Name: VMMaker.oscog-eem.2006
Author: eem
Time: 25 November 2016, 7:19:10.023637 pm
UUID: cad39d34-1c14-416f-aeae-5b9fc776a3fc
Ancestors: VMMaker.oscog-eem.2005

RegisterAllocatingCogit:
methodOrBlockNumTemps must not be reset to the actual value ignoring the initial pushNils.  Doing so wrecks spilling.

scanMethod must add an extra fixup for conditional branches since, if preceded by a special selector send, there may be two fixups created, one for each target, the target of the jump and the fall-through after the non-inlined send (see e.g. the two ensureFixupAt: sends in genBinaryInlineComparison:opFalse:destReg:).

This gets execution as far as the send of #<= in the loop in Interval>>#collect: which ends up passing nil as the second argument.  It maybe time to tackle inlining of special selector comparisons.

=============== Diff against VMMaker.oscog-eem.2005 ===============

Item was changed:
  ----- Method: StackToRegisterMappingCogit>>compileBlockFrameBuild: (in category 'compile abstract instructions') -----
  compileBlockFrameBuild: blockStart
  	"Build a frame for a block activation.  See CoInterpreter class>>initializeFrameIndices.
  	 Override to push the register receiver and register arguments, if any, and to correctly
  	 initialize the explicitly nilled/pushed temp entries (they are /not/ of type constant nil)."
  	super compileBlockFrameBuild: blockStart.
  	methodOrBlockNumTemps := blockStart numArgs + blockStart numCopied + blockStart numInitialNils.
  	self initSimStackForFramefulMethod: blockStart startpc.
  	blockStart numInitialNils > 0 ifTrue:
  		[blockStart numInitialNils > 1
  			ifTrue:
  				[self genMoveNilR: TempReg.
  				 1 to: blockStart numInitialNils do:
  					[:ign| self PushR: TempReg]]
  			ifFalse:
+ 				[self genPushConstant: objectMemory nilObject]]!
- 				[self genPushConstant: objectMemory nilObject].
- 		 methodOrBlockNumTemps := blockStart numArgs + blockStart numCopied]!

Item was changed:
  ----- Method: StackToRegisterMappingCogit>>scanMethod (in category 'compile abstract instructions') -----
  scanMethod
  	"Scan the method (and all embedded blocks) to determine
  		- what the last bytecode is; extra bytes at the end of a method are used to encode things like source pointers or temp names
  		- if the method needs a frame or not
  		- what are the targets of any backward branches.
  		- how many blocks it creates
  	 Answer the block count or on error a negative error code"
  	| latestContinuation nExts descriptor pc numBlocks distance targetPC framelessStackDelta seenInstVarStore |
  	<var: #descriptor type: #'BytecodeDescriptor *'>
  	needsFrame := useTwoPaths := seenInstVarStore := false.
  	LowcodeVM ifTrue: [ hasNativeFrame := false ].
  	self maybeInitNumFixups.
  	self maybeInitNumCounters.
  	prevBCDescriptor := nil.
  	NewspeakVM ifTrue:
  		[numIRCs := 0].
  	(primitiveIndex > 0
  	 and: [coInterpreter isQuickPrimitiveIndex: primitiveIndex]) ifTrue:
  		[^0].
  	pc := latestContinuation := initialPC.
  	numBlocks := framelessStackDelta := nExts := extA := extB := 0.
  	[pc <= endPC] whileTrue:
  		[byte0 := (objectMemory fetchByte: pc ofObject: methodObj) + bytecodeSetOffset.
  		 descriptor := self generatorAt: byte0.
  		 descriptor isExtension ifTrue:
  			[descriptor opcode = Nop ifTrue: "unknown bytecode tag; see Cogit class>>#generatorTableFrom:"
  				[^EncounteredUnknownBytecode].
  			 self loadSubsequentBytesForDescriptor: descriptor at: pc.
  			 self perform: descriptor generator].
  		 (descriptor isReturn
  		  and: [pc >= latestContinuation]) ifTrue:
  			[endPC := pc].
  
  		  needsFrame ifFalse:
  			[(descriptor needsFrameFunction isNil
  			  or: [self perform: descriptor needsFrameFunction with: framelessStackDelta])
  					ifTrue:
  						["With immutability we win simply by avoiding a frame build if the receiver is young and not immutable."
  						 self cppIf: IMMUTABILITY
  							ifTrue: [descriptor is1ByteInstVarStore
  									ifTrue: [useTwoPaths := true]
  									ifFalse: [needsFrame := true. useTwoPaths := false]]
  							ifFalse: [needsFrame := true. useTwoPaths := false]]
  					ifFalse:
  						[framelessStackDelta := framelessStackDelta + descriptor stackDelta.
  						 "Without immutability we win if there are two or more stores and the receiver is new."
  						 self cppIf: IMMUTABILITY
  							ifTrue: []
  							ifFalse:
  								[descriptor is1ByteInstVarStore ifTrue:
  									[seenInstVarStore
  										ifTrue: [useTwoPaths := true]
  										ifFalse: [seenInstVarStore := true]]]]].
  
  		 descriptor isBranch ifTrue:
  			[distance := self spanFor: descriptor at: pc exts: nExts in: methodObj.
  			 targetPC := pc + descriptor numBytes + distance.
  			 (self isBackwardBranch: descriptor at: pc exts: nExts in: methodObj)
  				ifTrue: [self initializeFixupAt: targetPC - initialPC]
  				ifFalse:
  					[latestContinuation := latestContinuation max: targetPC.
+ 					 (descriptor isBranchTrue or: [descriptor isBranchFalse]) ifTrue:
+ 						[self maybeCountFixup].
  					 self maybeCountFixup.
  					 self maybeCountCounter]].
  		 descriptor isBlockCreation ifTrue:
  			[numBlocks := numBlocks + 1.
  			 distance := self spanFor: descriptor at: pc exts: nExts in: methodObj.
  			 targetPC := pc + descriptor numBytes + distance.
  			 latestContinuation := latestContinuation max: targetPC.
  			 self maybeCountFixup].
  
  		 NewspeakVM ifTrue:
+ 			[descriptor hasIRC ifTrue: [numIRCs := numIRCs + 1]].
- 			[descriptor hasIRC ifTrue:
- 				[numIRCs := numIRCs + 1]].
  		 pc := pc + descriptor numBytes.
+ 		 nExts := descriptor isExtension ifTrue: [nExts + 1] ifFalse: [extA := extB := 0].
- 		 descriptor isExtension
- 			ifTrue: [nExts := nExts + 1]
- 			ifFalse: [nExts := extA := extB := 0].
  		 prevBCDescriptor := descriptor].
  	^numBlocks!