[Vm-dev] Re: [Vm-beginners] how can I check which selector is the VM executing?

[Yoshiki Ohshima]

At Thu, 28 Apr 2011 12:22:33 +0200,
Mariano Martinez Peck wrote:
> 
> Hi. Suppose I am doing something in #commonSend:
> 
> commonSend
>     "Send a message, starting lookup with the receiver's class."
>     "Assume: messageSelector and argumentCount have been set, and that
> the receiver and arguments have been pushed onto the stack,"
> "Note: This method is inlined into the interpreter dispatch loop."
> <sharedCodeNamed: 'commonSend' inCase: 131>
> self internalFindNewMethod.
> self internalExecuteNewMethod.
> self fetchNextBytecode
> 
> and somewhere there I want to do something like this:
> 
> (messageSelector = '#foo') ifTrue: [ self print: 'the message foo was called'; cr ].
> 
> messageSelector is the instVar of Interpreter and it is already in the stack.
> 
> Of course, the part that doesn't work is (messageSelector = '#foo')
> I tried several things but I don't find how to do it.

  Perhaps something along the line of:

  (self cCode: 'stSizeOf(messageSelector) == sizeOf('foo') && (strncmp(firstIndexableField(messageSelector), 'foo',
     sizeOf('foo')) == 0)) ifTrue: [self print: 'the message foo was called': cr].

  (Not tested this particualr one, but have done similar thing
before.  This assumes that messageSelector is always a Symbol, which
may not be the case for you...)

-- Yoshiki