[PATCH] readelf: Add some support for locviews.

[Mark Wielaard]

On Thu, 2018-03-01 at 14:55 +0100, Mark Wielaard wrote:
> This adds minimal support for locviews as output by GCC8.
> It changes readelf to keep track of loclistptrs from DW_AT_GNU_locviews
> and prints the locview pairs for those. Since there is no terminator
> we have to keep track of where the next loclist entry starts.
> The --debug-dump=loc output looks as follows:
> 
>  CU [   714] base: +0x0000000000003020 <elf_hash>
>  [    b4] view pair 1, 2
>  [    b6] range 4, 7f
>           +0x0000000000003024 <elf_hash+0x4>..
>           +0x000000000000309e <elf_hash+0x7e>
>            [ 0] reg5
>  [    d9] view pair 3, 1
>           view pair 1, 2
>  [    dd] range 4, 4c
>           +0x0000000000003024 <elf_hash+0x4>..
>           +0x000000000000306b <elf_hash+0x4b>
>            [ 0] reg5
>           range 4c, 7f
>           +0x000000000000306c <elf_hash+0x4c>..
>           +0x000000000000309e <elf_hash+0x7e>
>            [ 0] reg2
> 
> Note that in the above output the view pairs correspond to the ranges
> immediately following in the loc list. This is how GCC8 currently
> outputs the locview pairs and ranges, but this is not guaranteed and
> you'll need to look at the location and GNU_locviews attributes of the
> DIE to know which really match up together. We might want to adjust the
> output to make this more clear.
> 
> This does not yet add an locview accessor to libdw. It just recognizes
> the DW_AT_GNU_locviews attribute as a loclistptr when encoded as a
> sec_offset form.

Pushed to master.