Re: [aspectj-dev] Getting source code positions for advice

[Andy Clement <andrew.clement@xxxxxxxxx>]

On 20 June 2011 13:23, Yoav A. <yoav_@xxxxxxxxxxx> wrote:
> What packages should I compile? I notice that getModel returns
> IStructureModel which is an interface  with no methods (at least in AJ 165).

You should treat the IStructureModel object as an AsmManager instance,
IStructureModel is a completely unfinished abstraction (empty - as you
noticed!).

> I am trying to modify weaver back end code to collect this info during weave
> time (BcelWeaver.weave).
> I will try to look into the running the parser. However, won't this mean
> that I compile every source file twice?

Parse it twice, not necessarily compile it twice.  I don't know what
you are up to so don't know if this is a problem for you.

> Then I will have to somehow match
> the BcelAdvice I have with the AST.

If you went down this route, yes you will need to match them up.
Advice has a robust name based on advice type, occurrence in the
aspect and hashcode of the pointcut text.

> I did consider using the LineNumberTable, it is already available at this
> stage using this code:
>
> BcelMethod method = (BcelMethod) adv.getSignature();
> LineNumberTable lnTable = method.getMethod().getLineNumberTable();
>
> Then I try to fetch the last line using:
>
> int length = lnTable.getLineNumberTable().length;
> int elnr = lnTable.getLineNumberTable()[length-1].getLineNumber()+1;
>
> However this does not work for advice that does not call return explicitly.
> The compiler adds a return instruction at the end of the method and adds it
> to the line number table at the last line. Now elnr is one line after the
> actual end of the advice.

I don't know what you want to do with the positions but working with
bytecode line number tables can be hit and miss.  If you need the
position of the closing curly brace you will always be out of luck
(you can guess relatively to the last instruction in the method but it
won't always be right).  And for the line where the actual declaration
is, well we added the methoddeclarationlinenumber attribute to the
advice methods so we know the declaration line rather than the line
with the first instruction on.  We've never added the same thing for
the end line, we haven't needed it.

I'd say use the structuremodel if you can, but it will only come out
if you drive compilation, not for pure weaving.

Andy

> -----Original Message----- From: Andy Clement
> Sent: Monday, June 20, 2011 10:01 PM
> To: AspectJ developer discussions
> Subject: Re: [aspectj-dev] Getting source code positions for advice
>
> If doing a full compile you can specify the option -emacssym and it
> will be created inside the World object and accessible through
> world.getModel().  If binary weaving (loadtime weaving), probably not,
> as the compiler creates a lot of the up front pieces of the structure
> - I'm not sure how you are operating the weaver in order to access the
> internals.
>
> You could look at the AJDT wiki article that talks about using the
> parser standalone:
>
> http://wiki.eclipse.org/Developer%27s_guide_to_building_tools_on_top_of_AJDT_and_AspectJ
>
> (obviously an ast for the file would give you accurate positions).
>
> Or you could access the bytecode and look at the line number table for
> the advice method, the last entry will give you an indication of where
> the last bit of code is in the advice.
>
> cheers
> Andy
>
> On 20 June 2011 11:42, Yoav A. <yoav_@xxxxxxxxxxx> wrote:
>>
>> is there some way to access this structure model from the weaver code?
>>
>>
>> -----Original Message----- From: Andy Clement
>> Sent: Monday, June 20, 2011 9:41 PM
>> To: AspectJ developer discussions
>> Subject: Re: [aspectj-dev] Getting source code positions for advice
>>
>> Hi,
>>
>> I doubt you are doing anything wrong.  We just never use the endline
>> (from BcelAdvice) for anything (as I recall) and so don't really
>> guarantee it is correct.  The structure model produced alongside the
>> compile is more likely to have correct information in it, as that is
>> used by AJDT.  Feel free to raise a bugzilla to sort out the
>> BcelAdvice end line if you like.
>>
>> cheers
>> Andy
>>
>> On 20 June 2011 11:25, Yoav A. <yoav_@xxxxxxxxxxx> wrote:
>>>
>>> I'm trying to extract source file information during the weaving process.
>>> I
>>> wrote the following code to fetch the beginning and end of an advice:
>>>
>>> public String getAdviceFormatString(BcelAdvice adv)
>>> {
>>>  ISourceLocation pos = adv.getSourceLocation(); int startLine =
>>> pos.getLine();
>>>  int endLine = pos.getEndLine(); // do the rest
>>> }
>>>
>>>
>>> I always get that startLine == endLine which correspond to the first line
>>> of
>>> the advice declaration. What am I doing wrong here?
>>>
>>>
>>>
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