[Vm-dev] [Pharo-project] is there a way to avoid all the #tryNamedPrimitive:with: * in ProtoObject

stephane ducasse stephane.ducasse at gmail.com
Wed Jan 25 21:32:14 UTC 2012


for the record mariano, VW implementation of method wrapper had a template of method one for each number of possible args 
and they reserved space in the compiled method to be able to binding the class name (from memory) so installing one was copy of the right template + homeClass + selector (not sure anymore) so it was quite fast and simple to read.

Stef

On Jan 25, 2012, at 7:36 PM, Mariano Martinez Peck wrote:

> 
> 
> Ok. I will try to give it a try to this approach as well. 
> But what happened with the version I attached in the previous email that uses a template method and just change the arguments number?
> 
> That would be fine.  I didn't look.
>  
> 
> Since I am quite newbie here and the change can be quite important, I would really appreciate if someone can take a look to the .cs so that I feel confident to commit it :) 
>  
>  
> but I get lost to get this working...the previous solution seems easier.
> 
> Do you want to build Trabants or BMWs?  
> 
> I didn't understand. Which solution which be each car?
> 
> Compiling from source each time = trabant.  Synthesizing directly = vw.   Using a template method = bmw.  
> 
> (vw = VisualWorks ;) )
> 
> 
> :):):):)
> 
> Nice because it means that we found a fast solution yet quite understandable :)
>  
>  
>  
> Documentation helps.
>  
> 
> I didn't understand either. If you refer to the fact I didn't put comments in the .cs I attached, I explicitly said in my previous email "If you agree, I can put a nice comment and commit.". It already took me the whole morning (yes, I am completly noob here) to do the version of changing the argument count, so I was waiting the confirmation in the solution before documenting it and make it better. 
> 
> I mean in general if one builds good quality code that is "clever" then that code needs to be documented.  Sometimes simple doesn't cut it (look at the complexity involved in making a VM fast).  So if simple doesn't cut it one must document.
> 
> Agree. Once someone gives me the OK for my .cs, I will add comments and commit.
> 
> Thanks Eliot. 
>  
> 
>  
>  
> 
> Thanks!
> 
> 
>  
> 
> On Tue, Jan 24, 2012 at 11:01 PM, Mariano Martinez Peck <marianopeck at gmail.com> wrote:
> 
> 
> Analogously, one needs a way of invoking named primitives in the debugger, and using tryNamedPrimitive[:with:with:...] et al has exactly the same weaknesses as tryPrimitiveN above.  So introducing a primitive to run named primitives is in keeping with tryPrimitive:withArgs:.  Using the VisualWorks approach is feasible but violates Occam's razor.
> 
> What what about temporally (to be removed in the future) just when we are using older VMs?
> 
> If temporary, then fine.  But its all work :)
> 
> 
> Well...writing papers can be boring ;)
> Please, could you take a look to the attached .cs?  I tried to do what I had in mind. Since this part of the system is new for me, I have not sure it is correct, nor how to test it. So far what I did for testing it is to take the  #tryNamedPrimitiveIn: aCompiledMethod for: aReceiver withArgs: arguments
> and (temporally) remove the <primitive: 218 error: ec> and define 'ec' as a temporal variable. Since it will be nil, the following code will be executed.
> Then I put a halt in #open: fileName forWrite: writeMode   from StandardFileStream and then I do it:
> FileDirectory default forceNewFileNamed: 'xxxxx'.
> Once in the debugger, I went to:
> 
> StandardFileStream retryWithGC:[self primOpen: f writable: writeMode] 
>                     until:[:id| id notNil] 
>                     forFileNamed: fileName.
> 
> did a "through" in the close, and be sure I could do "into" and "step" for #self primOpen: f writable: writeMode  (which is a named primitive).
> 
> is this ok?
> 
> Thanks Eliot!
> 
>   
>  
>  
> 
> Why do we need them in ProtoObject?
> 
> Once tryNamedPrimitiveIn:for:withArgs: is implemented in all relevant virtual machines we don't need them.  You'll notice that there is no trace of the tryPrimitiveN methods anymore, even though they're in Smalltalk-80.
>  
> Because I'm not sure that adding primitive to VM is always a good solution.
> 
> Agreed.  But it is in keeping with the primitive for invoking numbered primitives,  tryPrimitive:withArgs:.
> 
> 
> HTH
> Eliot
> 
> 
> Stef
> 
> > On Mon, Jan 23, 2012 at 8:52 AM, Mariano Martinez Peck <marianopeck at gmail.com> wrote:
> > Hi guys. I usually like to take a look to ProtoObject and see what is really needed for the minimal object. But having 30% of the methods being  #tryNamedPrimitive:with: *  is not fun.
> > So...I wonder, do you think there could be another way so that to avoid having all those methods in ProtoObject ?
> >
> > Yes there is.  I implemented primitive 218 in Cog, primitiveDoNamedPrimitiveWithArgs, which is accessed via
> >
> >
> >               tryNamedPrimitiveIn: aCompiledMethod for: aReceiver withArgs: arguments
> >                       | selector theMethod spec receiverClass |
> >                       <primitive: 218 error: ec>
> >                       ec ifNotNil:
> >                               ["If ec is an integer other than -1 there was a problem with primitive 218,
> >                                 not with the external primitive itself.  -1 indicates a generic failure (where
> >                                 ec should be nil) but ec = nil means primitive 218 is not implemented.  So
> >                                 interpret -1 to mean the external primitive failed with a nil error code."
> >                                ec isInteger ifTrue:
> >                                       [ec = -1
> >                                               ifTrue: [ec := nil]
> >                                               ifFalse: [self primitiveFailed]].
> >                               ^{PrimitiveFailToken. ec}].
> >                       "Assume a nil error code implies the primitive is not implemented and fall back on the old code."
> >                       "Hack. Attempt to execute the named primitive from the given compiled method"
> >                       arguments size > 8 ifTrue:
> >                               [^{PrimitiveFailToken. nil}].
> >                       selector := #(
> >                               tryNamedPrimitive
> >                               tryNamedPrimitive:
> >                               tryNamedPrimitive:with:
> >                               tryNamedPrimitive:with:with:
> >                               tryNamedPrimitive:with:with:with:
> >                               tryNamedPrimitive:with:with:with:with:
> >                               tryNamedPrimitive:with:with:with:with:with:
> >                               tryNamedPrimitive:with:with:with:with:with:with:
> >                               tryNamedPrimitive:with:with:with:with:with:with:with:) at: arguments size+1.
> >                       receiverClass := self objectClass: aReceiver.
> >                       theMethod := receiverClass lookupSelector: selector.
> >                       theMethod == nil ifTrue:
> >                               [^{PrimitiveFailToken. nil}].
> >                       spec := theMethod literalAt: 1.
> >                       spec replaceFrom: 1 to: spec size with: (aCompiledMethod literalAt: 1) startingAt: 1.
> >                       Smalltalk unbindExternalPrimitives.
> >                       ^self object: aReceiver perform: selector withArguments: arguments inClass: receiverClass
> >
> > (cf tryPrimitive: withArgs:) and used in
> >
> >
> >               doPrimitive: primitiveIndex method: meth receiver: receiver args: arguments
> >                       "Simulate a primitive method whose index is primitiveIndex.  The simulated receiver
> >                        and arguments are given as arguments to this message. Any primitive which provokes
> >                        execution needs to be intercepted and simulated to avoid execution running away."
> >
> >                       | value |
> >                       "If successful, push result and return resuming context, else ^ { PrimitiveFailToken. errorCode }"
> >                       (primitiveIndex = 19) ifTrue:
> >                               [ToolSet
> >                                       debugContext: self
> >                                       label:'Code simulation error'
> >                                       contents: nil].
> >
> >                       "ContextPart>>blockCopy:; simulated to get startpc right"
> >                       (primitiveIndex = 80 and: [(self objectClass: receiver) includesBehavior: ContextPart])
> >                               ifTrue: [^self push: ((BlockContext newForMethod: receiver method)
> >                                                               home: receiver home
> >                                                               startpc: pc + 2
> >                                                               nargs: (arguments at: 1))].
> >                       (primitiveIndex = 81 and: [(self objectClass: receiver) == BlockContext]) "BlockContext>>value[:value:...]"
> >                               ifTrue: [^receiver pushArgs: arguments from: self].
> >                       (primitiveIndex = 82 and: [(self objectClass: receiver) == BlockContext]) "BlockContext>>valueWithArguments:"
> >                               ifTrue: [^receiver pushArgs: arguments first from: self].
> >                       primitiveIndex = 83 "afr 9/11/1998 19:50" "Object>>perform:[with:...]"
> >                               ifTrue: [^self send: arguments first
> >                                                       to: receiver
> >                                                       with: arguments allButFirst
> >                                                       super: false].
> >                       primitiveIndex = 84 "afr 9/11/1998 19:50 & eem 8/18/2009 17:04" "Object>>perform:withArguments:"
> >                               ifTrue: [^self send: arguments first
> >                                                       to: receiver
> >                                                       with: (arguments at: 2)
> >                                                       startClass: nil].
> >                       primitiveIndex = 100 "eem 8/18/2009 16:57" "Object>>perform:withArguments:inSuperclass:"
> >                               ifTrue: [^self send: arguments first
> >                                                       to: receiver
> >                                                       with: (arguments at: 2)
> >                                                       startClass: (arguments at: 3)].
> >
> >                       "Mutex>>primitiveEnterCriticalSection
> >                        Mutex>>primitiveTestAndSetOwnershipOfCriticalSection"
> >                       (primitiveIndex = 186 or: [primitiveIndex = 187]) ifTrue:
> >                               [| active effective |
> >                                active := Processor activeProcess.
> >                                effective := active effectiveProcess.
> >                                "active == effective"
> >                                value := primitiveIndex = 186
> >                                                       ifTrue: [receiver primitiveEnterCriticalSectionOnBehalfOf: effective]
> >                                                       ifFalse: [receiver primitiveTestAndSetOwnershipOfCriticalSectionOnBehalfOf: effective].
> >                                ^(value isArray
> >                                   and: [value size = 2
> >                                   and: [value first == PrimitiveFailToken]])
> >                                       ifTrue: [value]
> >                                       ifFalse: [self push: value]].
> >
> >                       primitiveIndex = 188 ifTrue: "eem 5/27/2008 11:10 Object>>withArgs:executeMethod:"
> >                               [^MethodContext
> >                                       sender: self
> >                                       receiver: receiver
> >                                       method: (arguments at: 2)
> >                                       arguments: (arguments at: 1)].
> >
> >                       "Closure primitives"
> >                       (primitiveIndex = 200 and: [self == receiver]) ifTrue:
> >                               "ContextPart>>closureCopy:copiedValues:; simulated to get startpc right"
> >                               [^self push: (BlockClosure
> >                                                               outerContext: receiver
> >                                                               startpc: pc + 2
> >                                                               numArgs: arguments first
> >                                                               copiedValues: arguments last)].
> >                       ((primitiveIndex between: 201 and: 205)                  "BlockClosure>>value[:value:...]"
> >                       or: [primitiveIndex between: 221 and: 222]) ifTrue: "BlockClosure>>valueNoContextSwitch[:]"
> >                               [^receiver simulateValueWithArguments: arguments caller: self].
> >                       primitiveIndex = 206 ifTrue:                                            "BlockClosure>>valueWithArguments:"
> >                               [^receiver simulateValueWithArguments: arguments first caller: self].
> >
> >                       primitiveIndex = 118 ifTrue: "tryPrimitive:withArgs:; avoid recursing in the VM"
> >                               [(arguments size = 2
> >                                and: [arguments first isInteger
> >                                and: [arguments last class == Array]]) ifFalse:
> >                                       [^ContextPart primitiveFailTokenFor: nil].
> >                                ^self doPrimitive: arguments first method: meth receiver: receiver args: arguments last].
> >
> >                       value := primitiveIndex = 120 "FFI method"
> >                                               ifTrue: [(meth literalAt: 1) tryInvokeWithArguments: arguments]
> >                                               ifFalse:
> >                                                       [primitiveIndex = 117 "named primitives"
> >                                                               ifTrue: [self tryNamedPrimitiveIn: meth for: receiver withArgs: arguments]
> >                                                               ifFalse:
> >                                                                       [receiver tryPrimitive: primitiveIndex withArgs: arguments]].
> >                       ^(value isArray
> >                           and: [value size = 2
> >                           and: [value first == PrimitiveFailToken]])
> >                               ifTrue: [value]
> >                               ifFalse: [self push: value]
> >
> > (find attached).  But these need implementing in the standard VM before they can be used in Pharo, Squeak, etc.
> >
> >
> > Thanks
> >
> > --
> > Mariano
> > http://marianopeck.wordpress.com
> >
> >
> >
> >
> > --
> > best,
> > Eliot
> >
> 
> 
> 
> 
> 
> -- 
> best,
> Eliot
> 
> 
> 
> 
> 
> -- 
> Mariano
> http://marianopeck.wordpress.com
> 
> 
> 
> 
> 
> -- 
> best,
> Eliot
> 
> 
> 
> 
> 
> -- 
> Mariano
> http://marianopeck.wordpress.com
> 
> 
> 
> 
> -- 
> Mariano
> http://marianopeck.wordpress.com
> 
> 
> 
> 
> 
> -- 
> best,
> Eliot
> 
> 
> 
> 
> 
> -- 
> Mariano
> http://marianopeck.wordpress.com
> 
> 
> 
> 
> 
> -- 
> best,
> Eliot
> 
> 
> 
> 
> 
> -- 
> Mariano
> http://marianopeck.wordpress.com
> 
> 
> 
> 
> 
> -- 
> best,
> Eliot
> 
> 
> 
> 
> 
> -- 
> Mariano
> http://marianopeck.wordpress.com
> 



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