Tracking method in and out with MetaLinks
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Tracking method in and out with MetaLinks
 
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Hi,
I stumbled upon another MetaLink scenario that I am unsure how to implement. I want to track method invocations, with receiver, arguments, selector, and return value (maybe even signaled exception). I can track the method input with a MetaLink installed on an RBMethodNode like this: MetaLink new metaObject: [ :c | Transcript show: c receiver; show: c method selector; show: c arguments; cr ]; selector: #value:; arguments: #(context). and for returns with a MetaLink on RBReturnNodes like this: MetaLink new metaObject: [ :v | Transcript show: v; cr ]; selector: #value:; arguments: #(value) The problem is though, that not all methods have explicit returns, and some mix explicit returns and self returns. I tried installed an #after MetaLink on a RBMethodNode, but this fails in many cases. Is there any way that I can instrument a method and track receiver, selector, arguments, and returned value (even if self) at the same time? Cheers, Manuel |
Re: Tracking method in and out with MetaLinks
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> On 23 Nov 2018, at 13:40, Manuel Leuenberger <[hidden email]> wrote: > > Hi, > > I stumbled upon another MetaLink scenario that I am unsure how to implement. I want to track method invocations, with receiver, arguments, selector, and return value (maybe even signaled exception). I can track the method input with a MetaLink installed on an RBMethodNode like this: > > MetaLink new > metaObject: [ :c | Transcript show: c receiver; show: c method selector; show: c arguments; cr ]; > selector: #value:; > arguments: #(context). > > and for returns with a MetaLink on RBReturnNodes like this: > > MetaLink new > metaObject: [ :v | Transcript show: v; cr ]; > selector: #value:; > arguments: #(value) > > The problem is though, that not all methods have explicit returns, and some mix explicit returns and self returns. I tried installed an #after MetaLink on a RBMethodNode, but this fails in many cases. Is there any way that I can instrument a method and track receiver, selector, arguments, and returned value (even if self) at the same time? > I am working now on making the #after work so that one can get with #value the return of the method… I now have a version where it works for Message Sends correctly *and* were #after on Method works better (the compilation errors should be fixed). But #value for #after on Method needs some more work… soon! I will commit this intermediate step now. Marcus |
Re: Tracking method in and out with MetaLinks
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Awesome! I am looking forward to it.
Cheers, Manuel
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Re: Tracking method in and out with MetaLinks
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In reply to this post by Marcus Denker-4
> On 23 Nov 2018, at 14:59, Marcus Denker <[hidden email]> wrote: > > > >> On 23 Nov 2018, at 13:40, Manuel Leuenberger <[hidden email]> wrote: >> >> Hi, >> >> I stumbled upon another MetaLink scenario that I am unsure how to implement. I want to track method invocations, with receiver, arguments, selector, and return value (maybe even signaled exception). I can track the method input with a MetaLink installed on an RBMethodNode like this: >> >> MetaLink new >> metaObject: [ :c | Transcript show: c receiver; show: c method selector; show: c arguments; cr ]; >> selector: #value:; >> arguments: #(context). >> >> and for returns with a MetaLink on RBReturnNodes like this: >> >> MetaLink new >> metaObject: [ :v | Transcript show: v; cr ]; >> selector: #value:; >> arguments: #(value) >> >> The problem is though, that not all methods have explicit returns, and some mix explicit returns and self returns. I tried installed an #after MetaLink on a RBMethodNode, but this fails in many cases. Is there any way that I can instrument a method and track receiver, selector, arguments, and returned value (even if self) at the same time? >> > > I am working now on making the #after work so that one can get with #value the return of the method… > > I now have a version where it works for Message Sends correctly *and* were #after on Method works better (the compilation errors should be fixed). > > But #value for #after on Method needs some more work… soon! > > I will commit this intermediate step now. > Here is the first step: https://github.com/pharo-project/pharo/pull/2011 • #operation for send after • #operation and value for {} arrays • #after hooks: preamble now executed before the operation • #after hooks: added concept of postamble, executed just before hook Next I need to look into #value for #after on methods. This got broken because we wrap the whole method in an exception handler (as #after should be called even if an exception happens). But this adds too much complexity… especially how it is done now. I think I will simplify that in a next step. Marcus |
Re: Tracking method in and out with MetaLinks
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#value for methods should now work with this PR loaded: This is implemented by compiling a wrapped method for #after (just as we do for primitives). Marcus |
Re: Tracking method in and out with MetaLinks
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In reply to this post by Marcus Denker-4
>>>
tests are green, so I merged it…
>>> I am working now on making the #after work so that one can get with #value the return of the method… >>> >>> I now have a version where it works for Message Sends correctly *and* were #after on Method works better (the compilation errors should be fixed). >>> >>> But #value for #after on Method needs some more work… soon! >>> > > #value for methods should now work with this PR loaded: > > https://github.com/pharo-project/pharo/pull/2012 > > This is implemented by compiling a wrapped method for #after (just as we do for primitives). > But I keep https://pharo.fogbugz.com/f/cases/22681/Metalink-on-message-may-break-compilation open for now: TODO for that issue: - test if the use case shown in this issue now works - write a test with the meta link from this issue to make sure this will not break in the future (the test should just apply it to an example, not a whole package, though. For speed) Marcus |
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