Re: Commit: readelf: Improve display of RELR relocations

[Nick Clifton <nickc@redhat.com>]

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Hi Fangrui Song,


> Relocation section '.relr.dyn' at offset 0x1f4 contains 2 entries:
> 
> Considering REL/RELA output, users might misinterpret "entries" as
> "relocation entries" instead of referring to RELR words.
> Overall, the number of relocation entries seems more valuable than the
> number of RELR words (users can infer the number from the section
> size, or the new "Index:" column).

A fair point.


>>    The patch also checks for malformed RELR entries (such as an entry
>>   with a value of just 1).
> 
> Trailing 1 can be utilized by linkers to avoid convergence issues
> (https://reviews.llvm.org/D67164):

Interesting.  I had not realised that that could happen.

So how about the attached patch ?  It changes the start of the RELR
section display so that it looks something like this:

   Relocation section '.relr.dyn' at offset 0x1a0 contains 3 entries which relocate 27 locations:

It also removes the warning about an no-op bitmap entry.

The patch is inefficient in that the section data is loaded twice, once
to count the entries and a second time to display them.  But this can
always be fixed up later if it proves to be a significant overhead.
In my testing I did not encounter any delays because of the double
load...

Cheers
   Nick


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