runtime compiled method optimizations

>
> That's it, the backward jumps use jumpFalse: and jumpTrue:.  It rings a
> bell.
>
> I am trying to transform these jumps to equivalent msg sends, only when
> the
> receiver is not the expected type.  This way, the normal fast transform
> works most of the time and when it is the wrong receiver we get a msg send
> in the image that I can intercept.  The best of both worlds.
> Unfortunately
> it more than doubles the bytecodes for these composite constructs, so I'd
> love to figure out the most compact forms.
>
> Perhaps the way to go is to define bytecodes for all combinations like
>     jumpFalseForIfTrue:
>     jumpFalseForIfFalse:
>     jumpFalseForIfTrueIfFalse:
>     jumpFalseForWhileFalse:
>     jumpTrueForWhileTrue:
>     jumpFalseForToDo:
> and so on.  Then I would need to figure out how to capture the blocks.
>
> Rob
>
> ----- Original Message -----
> From: "nicolas cellier" <[hidden email]>
> To: <[hidden email]>
> Sent: Friday, October 19, 2007 12:17 PM
> Subject: Re: runtime compiled method optimizations
>
>
> > You will also have backward jumps generated by loops (to:do: whileTrue:
> > whileFalse:)...
> >
> > Though you might be able to transform all these jumps in equivalent
> > message send (See Decompiler), that's might be impracticle to do that at
> > interpreter level.
> >
> >
> > Rob Withers a écrit :
> >>
> >> ----- Original Message ----- From: "Igor Stasenko" <[hidden email]>
> >> To: "The general-purpose Squeak developers list"
> >> <[hidden email]>
> >> Sent: Thursday, October 18, 2007 11:58 PM
> >> Subject: Re: runtime compiled method optimizations
> >>
> >>
> >>> On 19/10/2007, Rob Withers <[hidden email]> wrote:
> >>>> Igor, I'm afraid you've lost me.  What would the bytecodes look like
> >>>> in
> >>>> your
> >>>> proposal?  From what you've said, wouldn't the #jumpFalse need to
> >>>> know
> >>>> what
> >>>> the literal to send is?  I also don't understand how it would extract
> >>>> the
> >>>> block contents.
> >>>
> >>> You don't need to change bytecode. Just by analysing that jump
> >>> bytecode jumps over a block. Then you can assume that bytes between
> >>> jump bytecode and byte where it points to is the block body.
> >>> So, you can do the trick by changing implementation of #jumpFalse.
> >>> By sending #IfTrue: message to receiver and checking the result.
> >>
> >> I'm still not getting it.  I am all about getting this functionality in
> >> the most compact form.  Are you saying that I should stick to the
> >> following bytecodes?
> >>
> >> 17 <10> pushTemp: 0
> >> 18 <9B> jumpFalse: 23
> >> 19 <10> pushTemp: 0
> >> 20 <20> pushConstant: 4
> >> 21 <B0> send: +
> >> 22 <7C> returnTop
> >> 23 <78> returnSelf
> >>
> >> Then if I am reading you right, the block is defined as
> >>    PC start of block := the PC of the jumpFalse: + 1
> >>    PC end of block := the PC of the arg to the jumpBlock - 1
> >> but I don't see where you setup and send the #blockCopy:
> >>
> >> I believe, but I am not sure, the #jumpFalse: is not only used for
> >> #ifTrue:, ifFalse:. ifTrue:ifFalse: and #ifFalse:ifTrue:, plus I want
> >> to
> >> be able to distinguish between these 4 methods.  Unless they all get
> >> transformed to #ifTrue:ifFalse: with appropriate nil blocks...
> >>
> >> Still, I am having a hard time understanding how #jumpFalse: suddenly
> >> knows to test for boolean (better than the testLocalReference), then if
> >> it is not boolean, instead of sending mustBeBoolean, do a couple of
> >> block
> >> copies and send #ifTrue:ifFalse:.  Can it do all that?  Can we have it
> >> scan the bytecodes of the current method to make decisions about the
> >> boundaries of the block copies?  Are we sure it should always send
> >> #ifTrue:ifFalse:?  You raise some interesting questions.
> >>
> >> Rob
> >>
> >>>
> >>>>
> >>>> thanks,
> >>>> Rob
> >>>>
> >>>>
> >>>> ----- Original Message -----
> >>>> From: "Igor Stasenko" <[hidden email]>
> >>>> To: "The general-purpose Squeak developers list"
> >>>> <[hidden email]>
> >>>> Sent: Thursday, October 18, 2007 3:06 PM
> >>>> Subject: Re: runtime compiled method optimizations
> >>>>
> >>>>
> >>>> > No, i think you'd better change the implementation of #jumpFalse
> >>>> > bytecode.
> >>>> > If you see that receiver is non-local , then simply do message
> >>>> > send.
> >>>> > And, i think you can safely use info from jump bytecode to extract
> >>>> > block contents
> >>>> > (bytes 19 - 22 is the block body).
> >>>> >
> >>>> > On 19/10/2007, Robert Withers <[hidden email]> wrote:
> >>>> >> Hi all,
> >>>> >>
> >>>> >> I have a simple method containing an ifTrue: message.  I have
> >>>> >> compiled it normally, which uses macro transformations:
> >>>> >>
> >>>> >> 17 <10> pushTemp: 0
> >>>> >> 18 <9B> jumpFalse: 23
> >>>> >> 19 <10> pushTemp: 0
> >>>> >> 20 <20> pushConstant: 4
> >>>> >> 21 <B0> send: +
> >>>> >> 22 <7C> returnTop
> >>>> >> 23 <78> returnSelf
> >>>> >>
> >>>> >> and I have compiled it using Klaus Witzel's nifty compiler changes
> >>>> >> to
> >>>> >> remove macro transformations and the result is an explicit message
> >>>> >> send of #ifTrue:
> >>>> >>
> >>>> >> 21 <10> pushTemp: 0
> >>>> >> 22 <89> pushThisContext:
> >>>> >> 23 <75> pushConstant: 0
> >>>> >> 24 <C8> send: blockCopy:
> >>>> >> 25 <A4 04> jumpTo: 31
> >>>> >> 27 <10> pushTemp: 0
> >>>> >> 28 <21> pushConstant: 4
> >>>> >> 29 <B0> send: +
> >>>> >> 30 <7C> returnTop
> >>>> >> 31 <E0> send: ifTrue:
> >>>> >> 32 <87> pop
> >>>> >> 33 <78> returnSelf
> >>>> >>
> >>>> >> I would like to check the receiver of the ifTrue:, the 1st method
> >>>> >> arg
> >>>> >> in this case (Temp: 0), to see if a certain situation exists (is
> >>>> >> it
> >>>> >> a
> >>>> >> local reference to an object?).  If it is true, I would like to
> >>>> >> run
> >>>> >> the optimal code from the first example, instead of the longer
> >>>> >> second
> >>>> >> example.   How could we do that?  Something like this?  Could it
> >>>> >> be
> >>>> >> done entirely by the compiler, given the existence of the bytecode
> >>>> >> routine for #testLocalReference?
> >>>> >>
> >>>> >> 21 <10> pushTemp: 0
> >>>> >> 22 <??> testLocalReference
> >>>> >> 23 <??> jumpFalse: 30
> >>>> >> 24 <10> pushTemp: 0
> >>>> >> 25 <??> jumpFalse: 40
> >>>> >> 26 <10> pushTemp: 0
> >>>> >> 27 <20> pushConstant: 4
> >>>> >> 28 <B0> send: +
> >>>> >> 29 <7C> returnTop
> >>>> >> 30 <89> pushThisContext:
> >>>> >> 31 <75> pushConstant: 0
> >>>> >> 32 <C8> send: blockCopy:
> >>>> >> 33 <?? ??> jumpTo: 38
> >>>> >> 34 <10> pushTemp: 0
> >>>> >> 35 <21> pushConstant: 4
> >>>> >> 36 <B0> send: +
> >>>> >> 37 <7C> returnTop
> >>>> >> 38 <E0> send: ifTrue:
> >>>> >> 39 <87> pop
> >>>> >> 40 <78> returnSelf
> >>>> >>
> >>>> >>
> >>>> >> Thanks!
> >>>> >> Rob
> >>>> >>
> >>>> >>
> >>>> >>
> >>>> >
> >>>> >
> >>>> > --
> >>>> > Best regards,
> >>>> > Igor Stasenko AKA sig.
> >>>> >
> >>>> >
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>> --
> >>> Best regards,
> >>> Igor Stasenko AKA sig.
> >>>
> >>>
> >>
> >>
> >>
> >
> >
> >
>
>