Re: [PATCH v3 1/2] gdb: dwarf2 generic implementation for caching function data

[Torbjorn SVENSSON <torbjorn.svensson@foss.st.com>]

On 2023-01-20 18:43, Simon Marchi wrote:
>> Maybe not a solution for now, but can't we use something like the trad-frame structs to cache
>> values/locations of registers for a given frame?
> 
> It's true that it's very similar, but I don't immediately see how I
> would use it in this case.  The trad-frame stuff saves the info in its
> own format, whereas here it would be nice to cache struct values
> directly.  And it wouldn't be optimal for trad-frame to cache values,
> because we would end up allocating values that might not be needed in
> the end.
> 
> However, I see that trad-frame uses an array of size
> gdbarch_num_cooked_regs.  It would make sense to use that here too,
> instead of a hash table, it makes the lookups O(1).
> 
> Simon

I think this is something that can be looked at later (GDB14?).

My first impression is that an array of pointers to struct value might 
work. If the pointer is nullptr, then there is no cached value, 
otherwise the pointer could be returned directly. But lest think of this 
after GDB13.