> I'm working on a tool that trace the excecution of the block (I need to know
> all the objects and methods touched by the block and the methodes inside
> these
> methods). With something like this :
>
> [ blablabla ] trace.
>
> So I want to mark the context with a flag to know if the current context is
> traced or not and in the method send_message I simply look at the flag in the
> current context and store the result or not.
>
> I've looked at the VM code and it seems that the contexts are allocated with
> the method alloc_stack_context. So in this method I initialise the trace
> variable with 0.
Have you checked that using DebugTools is too slow?
Initialization of the new context is done in activate_new_context,
that's probably a better place.
Also, alternatively you can use the checks that are already in place for
the profiler, so that you don't introduce more ifs on a very hpt path.
Alternatively, what about instrumenting the methods and replacing them
dynamically? That is, rewrite something like:
self abc.
self def: 3.
to
Tracer current on: self perform: #abc.
Tracer current on: self perform: #def: with: 3.
Inside the tracer object, you keep a mapping between untraced methods
and traced methods, and do something like:
on: receiver perform: aSymbol
| method |
"Make this a primitive if it is too slow."
method := receiver class lookupSelector: aSymbol.
method isNil ifTrue: [ ... handle doesNotUnderstand ... ].
self on: receiver trace: method.
^receiver perform: (self tracingMethodAt: method)
Right now there is no instruction stream class (it's all in STCompiler
in the Parser package), but maybe you have already written one? :-)
Paolo
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