Re: [Wala-wala] JSR 308 "Type Annotations" Support

[Julian D. <do...@us...>]

Martin,

  That all sounds good.  I guess I should have read the code more carefully
before commenting; the integration with annotations looks very nice.

	-- Julian



From:	Martin Hecker <mar...@ki...>
To:	wal...@li...
Date:	11/28/2016 11:22 AM
Subject:	Re: [Wala-wala] JSR 308 "Type Annotations" Support



On 11/28/2016 04:41 PM, Julian Dolby wrote:
> This looks very nice, and I would definitely be in favour of having it as
part of WALA core!

Great! I will eventually provide a pull-request then - once I've
incorporated any suggestions that come up here in this
thread.


> 1) Maybe we can minimize the space cost of the bytecode index mapping
arrays by using the existing mapping. Since that
> is an array from instruction index to bytecode offset, we ought to be
able to use binary search on that array for a
> reverse mapping. Logarithmic time should be fine, given that the bytecode
size is limited anyway.

That's a great idea, I will look into implementing this and report back!


> We can do that if the bytecode order is always sorted; it should be since
I think Shrike only ever messes with the order
> of bytecodes when JSRs are used, and they are not allowed in newer code
anyway.

So do you reckon one would use such a "fast" implementation whenever no
JSRs are present, and fall back to some slower
search when JSRs are present?


> 2) It looks from JSR 308 that there is a lot of sharing of formats
between the new type annotations and the previous
> annotations of Java 7. It would be great if that commonality could be
reflected as much as possible in the code of the
> AnnotationsReader and the TypeAnnotationReader.
 >
 > For instance, the type_annotation structure in JSR308 appears to be an
extension of the annotation structure from
 > previous versions of Java.

Currently, this is reflected in TypeAnnotationReader in so far as that

   Pair<TypeAnnotationAttribute, Integer>
TypeAnnotationReader.getTypeAttributeAndSize(int begin)

calls the existing method

   Pair<    AnnotationAttribute, Integer>
AnnotationsReader.getAttributeAndSize(int begin)

in order to parse the part of the type annotation that is shared with
"normal" annotations as specified in


https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.7.16



> It might aid ultimate integration into the WALA IR annotation structures,
if that could be
> reflected somehow in the Shrike structures, that would be great.

With regard to the WALA (as opposed to: Shrike) structures, the
TypeAnnotation class is composed from the the existing
WALA Annotation class like this:

public class TypeAnnotation {

   private final Annotation annotation;
                 ^^^^^^^^^^

   private final List<Pair<TypePathKind, Integer>> typePath;
   private final TypeAnnotationTarget typeAnnotationTarget;
   private final TargetType targetType;

   ...
}


Greetings,

Martin


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