Re: [PATCH] dwarf2: Fix dwarf stack fetch array view size mismatch

[Denis Lukianov <denis@voxelsoft.com>]

On Sat, 2022-08-20 at 02:38 +0100, Denis Lukianov wrote:
> 
> I know nothing about gdb internals, just reading code in the file:
> 
> copy (value_contents_all (val).slice (subobj_offset, len),
>                   value_contents_raw (retval));
> 
> We know val is allocated to be the length of subobj_type.
> We know retval is allocated to be the length of subobj_type.
> We know len is the length of subobj_type.
> We know slice only gives a view same size or smaller.
> 
> So, the source array_view length must be len - subobj_offset.
> 
> Therefore source array_view size will be of the length of subobj_type
> and match the destination only in the event that subobj_offset
> happens
> to be zero. The line above does not guarantee it:
> 
> subobj_offset += n - max;
> 
> So it looks broken for big endian systems. And maybe any subtype that
> is not the first element of a type on the others.
> 

My bad, val is allocated to be length of type.

So I'm wrong about all this and the code is fine :)