Re: [PATCH] [gdb/symtab] Add assert in free_cached_comp_units constructor

[Tom de Vries <tdevries@suse.de>]

On 5/30/26 2:52 PM, Tom de Vries wrote:
> On 5/28/26 6:43 PM, Tom Tromey wrote:
>>>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:
>>
>> Tom> Detect this situation using an assert in the free_cached_comp_units
>> Tom> constructor.
>>
>> Seems fine to me.
> 
> Thanks for the review.
> 
> I committed this, but afterwards ran into trouble on x86_64-linux with 
> test-cases gdb.ada/uninitialized-variable-record.exp and gdb.ada/ 
> uninitialized_vars.exp on x86_64-linux, so I've reverted this.
> 

I've investigated this, and found that this is due to calls to load_cu 
in places other than dw2_do_instantiate_symtab.

For test-case gdb.ada/uninitialized_vars.exp, it's 
dwarf2_fetch_die_loc_cu_off.

I do wonder if ~free_cached_comp_units is a bit overeager, and should 
refrain from deleting cached comp units that were present at 
construction time.

Anyway, the assert detected the use-after-free I created, but just 
doesn't hold in general.

Thanks,
- Tom

> Thanks,
> - Tom
> 
>>
>> Approved-By: Tom Tromey <tom@tromey.com>
>>
>> Tom
>