Fixed issue where abstract_orgin is DW_FORM_ref_addr instead of DW_FORM_ref4

[calebh]

This fixes issue #589 (see that issue for more information on this pull request)

I'm not sure if the resolve_abstract_origin function should be further abstracted to resolve references that are not only abstract_origin.

[ltfish]

LGTM. @rhelmot ?

[rhelmot]

lgtm, but can we throw an error if the form is not something we've explicitly got a case to handle?

[calebh]

lgtm, but can we throw an error if the form is not something we've explicitly got a case to handle?

Sure, we can do that. As I've been going through the DWARF code, I've been finding tons of places where it's assumed that a ref4 relative reference is used. I might end up changing all of these to account for the possibility of an absolute reference.

[calebh]

@rhelmot I have pushed another commit that further abstract the reference resolving to work with any reference attribute. I went ahead and changed all the functions that previously had hard coded relative offset calculations to use the new functions.

References of unsupported form will now throw a ValueError. According to the DWARF specs, the specific forms that are still unsupported are DW_FORM_ref_sig8, DW_FORM_ref_sup4, and DW_FORM_ref_sup8. I don't happen to have any binaries handy with these specific reference forms, so I'm not sure how to implement and test them.

[rhelmot]

This diff looks good, can you please address the formatting issues by running pre-commit?

[calebh]

I was able to further simplify the code by making use of the get_DIE_from_attribute method available from a DIE object. Using this method means that we now support all the different types of references used by the elftools DWARF library. I also made sure that the lines are under the character limit as the last pre-commit pointed out.

[rhelmot]

I'm sorry I failed to follow up on this - you are still having some issues with our lint and autoformatter. Can you please run pip install pre-commit && pre-commit run, or allow us to push to your fork so I can do it for you?