[Vm-dev] VM Maker: VMMaker.oscog-cb.2105.mcz

[Clément Bera]

On Thu, Jan 19, 2017 at 2:31 PM, Ronie Salgado <roniesalg at gmail.com> wrote:

>
> Hi Clement,
>
> Something is fishy in debugStackPointers in the SistaVM. It fails multiple
>> assertion. I believe it's related tobranchIfInstanceOf bytecodes
>
> I think that the problem is in  stackDeltaForPrimitive:in:. An unary
> inline primitive has a stack delta of zero (Consumes one value and produce
> another value: -1 + 1 = 0). A binary inline primitive has a stack delta of
> -1 (Consumes 2 value, produce one value: -2 + 1 = -1) . A ternary inline
> primitive has a stack delta of -2. (Consume three values, produce one
> value: -3 + 1 = -2).
>
> I think that this is the correct definition for the method:
>
> stackDeltaForPrimitive: primitiveIndex in: method
> "Answer the stack delta for the callPrimitive: bytecode (see my class
> comment).
> There is no delta for non-inlined primitives (its implicitly 0 - method
> numArgs).
> Inlined primitives are grouped by the thousand by argument count, 32 args
> max ;-)."
> | prim primSet |
> ^primitiveIndex < 32678
> ifTrue: [0]
> ifFalse: [
> primSet := (primitiveIndex - 32768) >> 13 bitAnd: 3.
> prim := (primitiveIndex - 32768) bitAnd: 8191.
> 1 - (prim // 1000)
> ]
>

Right.

Currently the StackDepthFinder implements both callPrimitive: and
callInlinePrimitive:, the dispatch being done in the instructionStream
based on the higher bit.

I think there are problems for your set because your set index is non zero,
but my set index is 0 and StackDepthFinder>>#callInlinePrimitive: compute,
as far as I understand it, the correct value.

Maybe we change the InstructionStream to call only callPrimitive, or we
change callInlinedPrimitive code to make this work with Lowcode.


> Best regards,
> Ronie
>
> 2017-01-19 8:19 GMT-03:00 <commits at source.squeak.org>:
>
>>
>> ClementBera uploaded a new version of VMMaker to project VM Maker:
>> http://source.squeak.org/VMMaker/VMMaker.oscog-cb.2105.mcz
>>
>> ==================== Summary ====================
>>
>> Name: VMMaker.oscog-cb.2105
>> Author: cb
>> Time: 19 January 2017, 12:19:42.246677 pm
>> UUID: 1f5ef635-cb7b-48c2-be74-4345d39c620f
>> Ancestors: VMMaker.oscog-cb.2104
>>
>> Set deadCode to true in trap bytecode to avoid generating merge machne
>> code that is never reached.
>>
>> Something is fishy in debugStackPointers in the SistaVM. It fails
>> multiple assertion. I believe it's related tobranchIfInstanceOf bytecodes
>>
>> =============== Diff against VMMaker.oscog-cb.2104 ===============
>>
>> Item was changed:
>>   ----- Method: SistaCogit>>genUnconditionalTrapBytecode (in category
>> 'bytecode generators') -----
>>   genUnconditionalTrapBytecode
>>         "SistaV1: *     217             Trap"
>>         self ssFlushTo: simStackPtr.
>>         self CallRT: ceTrapTrampoline.
>>         self annotateBytecode: self Label.
>> +       deadCode := true.
>>         ^0!
>>
>>
>
>
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